Laurie Barclay, MD
Charles P. Vega, MD
From Medscape Medical News
July 27, 2009 — Modestly reducing salt intake is associated with significant decreases in blood pressure in blacks, Asians and whites, according to the results of a randomized, double-blind, crossover trial reported online in the July 20 issue of Hypertension. Most previous trials were in whites, with few in blacks and Asians.
"A lower salt intake, in the long-term, could play an important role in the prevention of cardiovascular disease, renal disease and osteoporosis," lead author Feng J. He, PhD, from St. George's, University of London, United Kingdom, said in a news release. "Our study provides further support for the current public health recommendations to reduce salt intake to less than 6 grams per day."
In this crossover trial, 71 whites, 69 blacks, and 29 Asians with untreated, mildly raised blood pressure underwent salt restriction with slow sodium or placebo, each for 6 weeks. Reduction in urinary sodium levels from slow sodium to placebo was from 165 ± 58 mmol/24 hours to 110 ± 49 mmol/24 hours (9.7 - 6.5 g/day salt).
This reduction in salt intake was associated with reductions in the following measures:
•blood pressure from 146 ± 13/91 ± 8 mm Hg to 141 ± 12/88 ± 9 mm Hg (P < .001),
•urinary albumin from 10.2 (interquartile range [IQR], 6.8 - 18.9) mg/24 hours to 9.1 (IQR, 6.6 - 14.0) mg/24 hours (P < .001),
•albumin/creatinine ratio from 0.81 (IQR, 0.47 - 1.43) mg/mmol to 0.66 (IQR, 0.44 - 1.22) mg/mmol (P < .001), and
•carotid-femoral pulse wave velocity from 11.5 ± 2.3 meters/second to 11.1 ± 1.9 meters/second (P < .01).
All 3 ethnic groups had significant decreases in blood pressure and urinary albumin/creatinine ratio with salt restriction, according to subgroup analysis. However, only blacks had a significant decrease in pulse wave velocity.
Based on the findings, the investigators concluded that a modest reduction in salt intake, comparable with the current public health recommendations, could cause significant reduction in blood pressure and urinary albumin levels in all 3 ethnic groups and could improve large-artery compliance.
"About 80 percent of salt intake in developed countries comes from sodium added by the food industry," said senior author Graham A. MacGregor, MD, also from St. George. "The best strategy to reduce salt intake in the population is to persuade the food industry to make a gradual and sustained reduction in the amount of salt added to food in a structured program across the whole of the food industry. This is now happening in the United Kingdom and the average salt intake has already fallen from 9.5 to 8.6 grams per day, and will continue to fall as more salt is taken out of all foods, with the saving of many lives."
Limitations of this study include relatively small sample size, particularly regarding Asians.
"Even a small reduction in blood pressure in the whole population would have a large impact on reducing the number of people suffering and/or dying from strokes, heart attacks and heart failure," Dr. MacGregor concluded.
•The World Health Organization recommends a daily salt intake of less than 5 g/day among adults.
•The current study finds that reduced salt intake improves blood pressure and urinary albumin excretion among whites, blacks, and Asians.
Saturday, August 8, 2009
FDA Approves Hydrocortisone/Acyclovir Cream for Treating Cold Sores
From Medscape Medical News
Yael Waknine
August 6, 2009 — The US Food and Drug Administration (FDA) has approved a hydrocortisone plus acyclovir cream (Lipsovir, Medivir AB) for the early treatment of recurrent herpes labialis — cold sores — to reduce the likelihood of ulcerative cold sores and to shorten the lesion healing time. Treatment is approved for adults and children aged 12 years and older.
The approval was based on data from a clinical phase 3 program showing that 42% of patients using hydrocortisone/acyclovir cream did not develop cold sores with blisters, ulcers, and crusting compared with 26% of those receiving placebo.
For those patients who developed cold sores, healing time was significantly decreased, being lowered by 1.5 days in the active treatment group vs in the placebo group.
"No product currently marketed for the treatment of cold sores has a corresponding label or has been shown to prevent an outbreak with early treatment," the company noted in a news release.
Yael Waknine
August 6, 2009 — The US Food and Drug Administration (FDA) has approved a hydrocortisone plus acyclovir cream (Lipsovir, Medivir AB) for the early treatment of recurrent herpes labialis — cold sores — to reduce the likelihood of ulcerative cold sores and to shorten the lesion healing time. Treatment is approved for adults and children aged 12 years and older.
The approval was based on data from a clinical phase 3 program showing that 42% of patients using hydrocortisone/acyclovir cream did not develop cold sores with blisters, ulcers, and crusting compared with 26% of those receiving placebo.
For those patients who developed cold sores, healing time was significantly decreased, being lowered by 1.5 days in the active treatment group vs in the placebo group.
"No product currently marketed for the treatment of cold sores has a corresponding label or has been shown to prevent an outbreak with early treatment," the company noted in a news release.
Penicillin Allergy Skin Testing Practical in ED;
Many Who Say They Have Allergy Don't
From Reuters Health Information
NEW YORK (Reuters Health) Aug 05 - Penicillin skin prick and cutaneous testing provides prompt results in emergency department patients with self-reported allergy. In most cases, that gives doctors more treatment options, according to researchers, because many of those who believe they are allergic to the antibiotic actually are not.
"It is feasible to determine if patients are truly allergic to penicillin in an emergency department setting," senior investigator Dr. Joseph J. Moellman told Reuters Health.
"Many patients that say they have an allergy," he added, "in actuality really do not when formally tested."
As reported in the July issue of the Annals of Emergency Medicine, Dr. Moellman of the University of Cincinnati College of Medicine, Ohio, and colleagues studied 150 patients with self-reported penicillin allergy.
Either of two physicians initially conducted skin tests in the patients, and if negative, intracutaneous testing was then employed. Total testing time was about 30 minutes.
The penicillin skin test result was negative in 137 of the patients, giving a false-positive rate for self-reported penicillin allergy of 91.3%. There were no adverse reactions associated with the testing.
"The clinical ramification of this study," continued Dr. Moellman, "is that many of these patients who might require penicillin to treat a specific infection would be able to receive penicillin if they tested negative to this skin test."
"This," he concluded, "would allow clinicians to avoid more costly alternative antibiotics and ultimately decrease drug resistance."
Ann Emerg Med 2009;54:72-77.
From Reuters Health Information
NEW YORK (Reuters Health) Aug 05 - Penicillin skin prick and cutaneous testing provides prompt results in emergency department patients with self-reported allergy. In most cases, that gives doctors more treatment options, according to researchers, because many of those who believe they are allergic to the antibiotic actually are not.
"It is feasible to determine if patients are truly allergic to penicillin in an emergency department setting," senior investigator Dr. Joseph J. Moellman told Reuters Health.
"Many patients that say they have an allergy," he added, "in actuality really do not when formally tested."
As reported in the July issue of the Annals of Emergency Medicine, Dr. Moellman of the University of Cincinnati College of Medicine, Ohio, and colleagues studied 150 patients with self-reported penicillin allergy.
Either of two physicians initially conducted skin tests in the patients, and if negative, intracutaneous testing was then employed. Total testing time was about 30 minutes.
The penicillin skin test result was negative in 137 of the patients, giving a false-positive rate for self-reported penicillin allergy of 91.3%. There were no adverse reactions associated with the testing.
"The clinical ramification of this study," continued Dr. Moellman, "is that many of these patients who might require penicillin to treat a specific infection would be able to receive penicillin if they tested negative to this skin test."
"This," he concluded, "would allow clinicians to avoid more costly alternative antibiotics and ultimately decrease drug resistance."
Ann Emerg Med 2009;54:72-77.
Thursday, August 6, 2009
A(H1N1) flu: Updates on 10 FAQs
Thursday August 6, 2009
by Dr David KL Quek
1) Can we distinguish between regular and H1N1 flu, without a lab test?
No, the flu is the flu, but there are variations in presentation. Some symptoms such as cough, runny nose, fever, body aches, fatigue, vomiting, diarrhoea occur more or less in every flu patient, but may present differently by different people. Some infected people have very mild symptoms, some in between, and a small minority, probably less than 10 per cent, have severe features including the dangerous pneumonia.
However, from sentinel testing and surveillance by the Ministry of Health the last few weeks have shown that almost 95 per cent of all flu-like illness are now caused by the H1N1 virus. Earlier some months ago, seasonal flu variants caused by the B and other A virus were the main causes, the bug causing most flu these few days is the A(H1N1). This appears to be the case also in neighbouring countries, meaning that the new virus is causing more havoc and symptomatic illness than previous types of flu (which are still in the community).
Because almost every flu-like illness (influenza-like illness or ILI) is due to H1N1, the MOH is now recommending that no testing to confirm this H1N1 will now be offered.
Treat as if this is H1N1 for ILI — symptom relief for mild symptoms (paracetamol, hydration, cough medicines, etc) and self-quarantine, social distancing, be alert for complications.
Most (70 per cent) do not need any anti-viral medications such as Tamiflu or Relenza. Only severe cases need to be referred to hospital for further treatment.
2) How should doctors decide if a person be given further specific treatment for H1N1?
If after 2-3 days, fever and cough symptoms do not improve, a recheck with the doctor is recommended, especially if there are features of difficulty breathing, severe weakness and giddiness, or, if the following risk factors are present:
1. obesity (fatter patients seem to have poorer outcome and more complications)
2. those with underlying diabetes, heart disease
3. those with asthma, or chronic lung disease
4. pregnant women
5. those with reduced immunity, cancer patients, etc
6. those with obvious pneumonia features
3) Many anxious people with flu-like symptoms want to be tested or treated for suspected H1N1, but are kept waiting or sent home, without being tested. Is this practice right?
There is no right or wrong practice as this outbreak is extensive and is stretching our resources to the limit. This is also the case not just here in Malaysia, but also elsewhere around the entire world!
The recommendation is now not to spend too much time and effort trying to get tested at designated hospitals or clinics — there is probably no need to do so. I have been informed that as many as 1,000 patients queue anxiously at Sungai Buloh Hospital for testing, due to fear of the H1N1 flu.
So the message must be made clear: Most flu illness do not require confirmatory testing, and are mild and self-limiting. More than 90 per cent will get better on their own, with symptomatic treatment — just watch out for possible complications, and risk factors as mentioned above.
Our resources are limited especially for testing. This is not just for Malaysia, but globally as well. The global demand for test kits and reagents for the H1N1 (PCR) is overextended and are rationed due to this extreme demand.
Some 200 million test kits have been deployed worldwide, but this supply is critically short because of excessive demand, so most countries have to ration testing to confirm only the worst cases, so as to monitor the pandemic better.
4) Are doctors confused as to what to do in this outbreak, especially when they do not have ready access to confirmatory lab tests?
Not really. Earlier on there was some confusion as to what to do next and who to test or who to refer for further testing and admission. Now the rules are clearer.
There is no need to do any testing to confirm the H1N1 virus for any ILI — just assume that this is the case in the majority of cases. Treat symptomatically when symptoms are mild, reassure the patients and ensure that these infected patients practice good personal hygiene, impose self-quarantine and social distancing, wear masks if their coughing or sneezing become troublesome, and keep a watchful eye on whether the infection is getting better or worse.
If there is difficulty breathing and gross weakness, then patients should quickly present themselves for admission. Understandably this phase of worsening is not always clear or easily understood by everyone... But there is not much more that we can do — otherwise we will be admitting too many patients and this will totally overwhelm our health services.
But prudent caution would help to determine which seriously ill patients need more attention and more intensive care. Unfortunately however, there will be that odd patient who will progress unusually quickly and collapse even before anything can be planned — hopefully these will be few and far between.
A more important note is that all doctors and nursing personnel should be very aware that they too have to take precautions, and employ barrier contact practices, if there are patients with cough and cold during this period of H1N1 outbreak, which is expected to last a year or two. Carelessness can result in the physician or nurse or nurse-aide becoming infected!
5) Are there sufficient guidelines from the Ministry of Health to address this situation?
I think there are sufficient guidelines from the MOH. Although some politicians have blamed the MOH and the minister for being inept at handling this pandemic — in truth this is not the case.
It is useful to remember that this is an entirely new or novel virus, which no one previously had encountered before — thus its infectivity and contagiousness is quite high and almost no one is immune to this virus.
Perhaps, there will come a time when all the resources from both public and private sectors can be put to more efficient use. Some logistic problems will invariably occur, because human beings differ in their capacity to understand or follow directives, whatever the source or authority.
Also patient demands have been extraordinarily high and at times very difficult to meet — every patient necessarily feels that his flu is potentially the worst possible type and therefore requires the most stringent measures and testing...
Doctors are also unsure as to the seriousness or severity of this new ailment — and we are only now beginning to understand this better — so our less than reassuring style when encountering this new H1N1 flu is sometimes detected by an equally anxious patient and/or their relatives.
But there is only so much that we can do under such a pressure cooker of an outbreak which is spreading like wildfire! But nevertheless we should not panic, and remember that most (more than 90 per cent) of infected people will recover with very little after-effects. Possibly only one in 10 patients develop more serious problems which necessitate hospitalisation.
6) Is limiting H1N1 testing only to those who have been admitted to hospital justifiable?
I have explained the worldwide shortage of such testing kits and reagents. Also it is near impossible to test everyone, the world over. Besides, knowing now that almost all the flu-like illness in the country is due to H1N1 makes it a moot point to want to test for this, especially when most are mild.
The rationale for testing only those who need hospitalisation is to ensure that we are dealing with the true virus, and also help to isolate possible changes or mutations to this viral strain. The MOH is also constantly doing sentinel surveillance (random spot-testing at various sites around the country to determine more accurately the various virus types and spread that are causing ILI).
7) Are we short of anti-virul drugs (Tamiflu, Relenza)? Should I take Tamiflu?
These antiviral drugs were available to most doctors during the earlier scare of the bird flu virus, but now are severely restricted, although some orders are still entertained from individual doctors, clinics or hospitals. Remember that these have been block-booked by more than 167 countries which have been shown to have been penetrated by the H1N1 flu bug.
Our MOH has actually stockpiled some two million doses of the Tamiflu or its generic form. In the last inter-ministerial pandemic influenza task force meeting, this stockpile will be bumped up to 5.5 million doses to cover some possible 20 per cent of the population.
Right now there is no shortage in the country. It is just that it is not readily available on demand for anyone just yet. The MOH is still of the opinion that this antiviral drug be used prudently and would like to register every patient given this drug.
The private sector on the other hand would like to have a looser control over the use of this drug — but we acknowledge that we should be meticulously prudent in its use. There is a genuine fear that resistant strains to this drug may develop with indiscriminate and unnecessary use — then we will all be in trouble with a drug-resistant H1N1 virus run amok!
Drug-resistant strains have been detected in Mexico, border-towns in the US, Vietnam, Britain, Australia even. So we have to be vigilant and closely monitor the situation. Right now, the very limited usage of Tamiflu gives us good reason to be optimistic.
However, because of some unusual patterns of seemingly well people dying or having very critical infections, some people and doctors are wondering if these new strains have already reached our shores... or have we been too late in instituting proper treatment...?
The rising number of deaths to 14 now is quite worrisome, but our health authorities are watching this development very closely and are also checking the virus strain to see if this has mutated. We can only hope that this is not the case, for now.
8) What are some of the problems faced by doctors in dealing with the H1N1 problem?
It would be good if every medical practitioner keeps a close tab on the H1N1 pandemic, and remain fully aware of the developments and changes, which are evolving daily. Every doctor has to be learning on the trot, so to speak, to keep up with the progress of this outbreak and its management, so that we can serve our patients better.
Logging in to the Internet regularly for more updated information will certainly help, instead of lamenting that not enough is being disseminated via the media thus far... Every doctor has to be more proactive and practice more responsible and cautious medicine during this trying period which is expected to run into at least one to two years. Importantly, look out for lung complications, and the above stated higher risk profiles, and refer these patients quickly for further care.
Easier access to antiviral drugs and their responsible use and monitoring would help allay public fears of delay in treatment, but this should be tempered with care and not over-exuberance to dish out to one and all, the precious antiviral drug, just for prevention — this may be a very bad move which can inadvertently create a worse outcome of drug-resistant bugs.
However, in the light of the very quick deterioration of some young patients who have died, it might be prudent to use antiviral treatment earlier and more aggressively.
We look forward to the specific H1N1 vaccine, when it does come our way, probably towards the end of the year. In the meantime, encouraging those in the front-line, heart or lung patients and frequent travellers to have the seasonal flu vaccination is a useful adjunct to help stem the usual problems from other flu types.
9) Are we doing everything that should or needs to be done?
Yes, if you check what other nations are doing, we are doing relatively well. We are not overstating the dangers and we have been quite transparent on the possibilities of this pandemic. Earlier, many agencies and even the public and doctors have accused us of exaggerating the pandemic, and our response was dismissed as being too much, even over the top! Unfortunately, it was only when some deaths occur that many are now decrying that we have done too little!
Also if you are quite honest about it, just compare with the countries globally, and you will notice that no one health or government authority has got this right, spot on.
We are all learning about this novel flu pandemic, and each country's response is coloured by its past experiences. In Hong Kong, China, Vietnam, Singapore and Malaysia we have had the SARS outbreak, so we are necessarily more paranoid! Also here the experience is that flu does not usually cause death in our community, unlike the west where seasonal flu kills some hundreds of thousands every year!
So the fear factor for this H1N1 flu is not nearly as great in the West, although it is slowly sinking in that its contagiousness and infectivity is far greater, and fears of its reassortment to a more virulent mutant form are growing, into the so-called second and/or third wave of this pandemic, but we will not know until a year or so down the line.
10) Is the public in general doing enough to help in controlling the outbreak?
I think the public is now reasonably well-informed as to this H1N1 pandemic. Perhaps, they are too well-informed, that they have a fearful approach to this virus. But the proper thing is not too over-react and to panic, although I know this does sound easier said than done.
It is almost a certainty that this flu will spread within the community — in schools, universities, academies, factories, work places, offices, etc. WHO has projected that possibly some 20-30 per cent of the population worldwide will become infected by this novel flu bug, after studying various models of spread of past infections — the huge and very rapid spread worldwide is mainly due to air travel. While older flu pandemics took six months to extend to so many countries, this H1N1 flu did so in less than six weeks!
In the worst-case scenarios of course, this outbreak will be alarming — hospitalisations may be required for 100,000 up to 500,000 Malaysians, with perhaps as many as 5,000 to 27,000 infected patients (depending on the case fatality rate or either 0.1 to 0.5 per cent) succumbing to this illness.
But because we have been monitoring closely and containing the outbreak thus far, with heightened awareness and greater social responsibility, it is possible to ameliorate the infectivity, spread and fatality that will unfortunately accompany this pandemic... Just how successful we will be in limiting these adverse outcomes remains to be seen, but we can be hopeful.
How can the public help? First learn and acquire good personal hygiene. If sick, please be responsible and stay at home, even in your own room where possible, wear a face mask (a cheap three-ply surgical mask will do, because large droplet spread is the main danger). Do not go out, practice what is now known as social distancing (about three metres from anyone), and be socially responsible, don't go to public places and infect others — for young people this would be hard, but absolutely necessary — the spread is most rampant in this age group between 16 and 25 years.
When the illness does not go away after a few days or when you are deteriorating, get to the nearest hospital. Most importantly, be very aware and responsible!
Finally, keep abreast of all new developments, because these are evolving all the time. With keen awareness, prudent care, early detection and social responsibility, correct and prompt use of antiviral and other support medical care, and later mass specific vaccination, we can overcome this novel H1N1 flu! But it will take time, patience, public cooperation, much concerted effort and consume great resources.
Dr David KL Quek is president the Malaysian Medical Association.
by Dr David KL Quek
1) Can we distinguish between regular and H1N1 flu, without a lab test?
No, the flu is the flu, but there are variations in presentation. Some symptoms such as cough, runny nose, fever, body aches, fatigue, vomiting, diarrhoea occur more or less in every flu patient, but may present differently by different people. Some infected people have very mild symptoms, some in between, and a small minority, probably less than 10 per cent, have severe features including the dangerous pneumonia.
However, from sentinel testing and surveillance by the Ministry of Health the last few weeks have shown that almost 95 per cent of all flu-like illness are now caused by the H1N1 virus. Earlier some months ago, seasonal flu variants caused by the B and other A virus were the main causes, the bug causing most flu these few days is the A(H1N1). This appears to be the case also in neighbouring countries, meaning that the new virus is causing more havoc and symptomatic illness than previous types of flu (which are still in the community).
Because almost every flu-like illness (influenza-like illness or ILI) is due to H1N1, the MOH is now recommending that no testing to confirm this H1N1 will now be offered.
Treat as if this is H1N1 for ILI — symptom relief for mild symptoms (paracetamol, hydration, cough medicines, etc) and self-quarantine, social distancing, be alert for complications.
Most (70 per cent) do not need any anti-viral medications such as Tamiflu or Relenza. Only severe cases need to be referred to hospital for further treatment.
2) How should doctors decide if a person be given further specific treatment for H1N1?
If after 2-3 days, fever and cough symptoms do not improve, a recheck with the doctor is recommended, especially if there are features of difficulty breathing, severe weakness and giddiness, or, if the following risk factors are present:
1. obesity (fatter patients seem to have poorer outcome and more complications)
2. those with underlying diabetes, heart disease
3. those with asthma, or chronic lung disease
4. pregnant women
5. those with reduced immunity, cancer patients, etc
6. those with obvious pneumonia features
3) Many anxious people with flu-like symptoms want to be tested or treated for suspected H1N1, but are kept waiting or sent home, without being tested. Is this practice right?
There is no right or wrong practice as this outbreak is extensive and is stretching our resources to the limit. This is also the case not just here in Malaysia, but also elsewhere around the entire world!
The recommendation is now not to spend too much time and effort trying to get tested at designated hospitals or clinics — there is probably no need to do so. I have been informed that as many as 1,000 patients queue anxiously at Sungai Buloh Hospital for testing, due to fear of the H1N1 flu.
So the message must be made clear: Most flu illness do not require confirmatory testing, and are mild and self-limiting. More than 90 per cent will get better on their own, with symptomatic treatment — just watch out for possible complications, and risk factors as mentioned above.
Our resources are limited especially for testing. This is not just for Malaysia, but globally as well. The global demand for test kits and reagents for the H1N1 (PCR) is overextended and are rationed due to this extreme demand.
Some 200 million test kits have been deployed worldwide, but this supply is critically short because of excessive demand, so most countries have to ration testing to confirm only the worst cases, so as to monitor the pandemic better.
4) Are doctors confused as to what to do in this outbreak, especially when they do not have ready access to confirmatory lab tests?
Not really. Earlier on there was some confusion as to what to do next and who to test or who to refer for further testing and admission. Now the rules are clearer.
There is no need to do any testing to confirm the H1N1 virus for any ILI — just assume that this is the case in the majority of cases. Treat symptomatically when symptoms are mild, reassure the patients and ensure that these infected patients practice good personal hygiene, impose self-quarantine and social distancing, wear masks if their coughing or sneezing become troublesome, and keep a watchful eye on whether the infection is getting better or worse.
If there is difficulty breathing and gross weakness, then patients should quickly present themselves for admission. Understandably this phase of worsening is not always clear or easily understood by everyone... But there is not much more that we can do — otherwise we will be admitting too many patients and this will totally overwhelm our health services.
But prudent caution would help to determine which seriously ill patients need more attention and more intensive care. Unfortunately however, there will be that odd patient who will progress unusually quickly and collapse even before anything can be planned — hopefully these will be few and far between.
A more important note is that all doctors and nursing personnel should be very aware that they too have to take precautions, and employ barrier contact practices, if there are patients with cough and cold during this period of H1N1 outbreak, which is expected to last a year or two. Carelessness can result in the physician or nurse or nurse-aide becoming infected!
5) Are there sufficient guidelines from the Ministry of Health to address this situation?
I think there are sufficient guidelines from the MOH. Although some politicians have blamed the MOH and the minister for being inept at handling this pandemic — in truth this is not the case.
It is useful to remember that this is an entirely new or novel virus, which no one previously had encountered before — thus its infectivity and contagiousness is quite high and almost no one is immune to this virus.
Perhaps, there will come a time when all the resources from both public and private sectors can be put to more efficient use. Some logistic problems will invariably occur, because human beings differ in their capacity to understand or follow directives, whatever the source or authority.
Also patient demands have been extraordinarily high and at times very difficult to meet — every patient necessarily feels that his flu is potentially the worst possible type and therefore requires the most stringent measures and testing...
Doctors are also unsure as to the seriousness or severity of this new ailment — and we are only now beginning to understand this better — so our less than reassuring style when encountering this new H1N1 flu is sometimes detected by an equally anxious patient and/or their relatives.
But there is only so much that we can do under such a pressure cooker of an outbreak which is spreading like wildfire! But nevertheless we should not panic, and remember that most (more than 90 per cent) of infected people will recover with very little after-effects. Possibly only one in 10 patients develop more serious problems which necessitate hospitalisation.
6) Is limiting H1N1 testing only to those who have been admitted to hospital justifiable?
I have explained the worldwide shortage of such testing kits and reagents. Also it is near impossible to test everyone, the world over. Besides, knowing now that almost all the flu-like illness in the country is due to H1N1 makes it a moot point to want to test for this, especially when most are mild.
The rationale for testing only those who need hospitalisation is to ensure that we are dealing with the true virus, and also help to isolate possible changes or mutations to this viral strain. The MOH is also constantly doing sentinel surveillance (random spot-testing at various sites around the country to determine more accurately the various virus types and spread that are causing ILI).
7) Are we short of anti-virul drugs (Tamiflu, Relenza)? Should I take Tamiflu?
These antiviral drugs were available to most doctors during the earlier scare of the bird flu virus, but now are severely restricted, although some orders are still entertained from individual doctors, clinics or hospitals. Remember that these have been block-booked by more than 167 countries which have been shown to have been penetrated by the H1N1 flu bug.
Our MOH has actually stockpiled some two million doses of the Tamiflu or its generic form. In the last inter-ministerial pandemic influenza task force meeting, this stockpile will be bumped up to 5.5 million doses to cover some possible 20 per cent of the population.
Right now there is no shortage in the country. It is just that it is not readily available on demand for anyone just yet. The MOH is still of the opinion that this antiviral drug be used prudently and would like to register every patient given this drug.
The private sector on the other hand would like to have a looser control over the use of this drug — but we acknowledge that we should be meticulously prudent in its use. There is a genuine fear that resistant strains to this drug may develop with indiscriminate and unnecessary use — then we will all be in trouble with a drug-resistant H1N1 virus run amok!
Drug-resistant strains have been detected in Mexico, border-towns in the US, Vietnam, Britain, Australia even. So we have to be vigilant and closely monitor the situation. Right now, the very limited usage of Tamiflu gives us good reason to be optimistic.
However, because of some unusual patterns of seemingly well people dying or having very critical infections, some people and doctors are wondering if these new strains have already reached our shores... or have we been too late in instituting proper treatment...?
The rising number of deaths to 14 now is quite worrisome, but our health authorities are watching this development very closely and are also checking the virus strain to see if this has mutated. We can only hope that this is not the case, for now.
8) What are some of the problems faced by doctors in dealing with the H1N1 problem?
It would be good if every medical practitioner keeps a close tab on the H1N1 pandemic, and remain fully aware of the developments and changes, which are evolving daily. Every doctor has to be learning on the trot, so to speak, to keep up with the progress of this outbreak and its management, so that we can serve our patients better.
Logging in to the Internet regularly for more updated information will certainly help, instead of lamenting that not enough is being disseminated via the media thus far... Every doctor has to be more proactive and practice more responsible and cautious medicine during this trying period which is expected to run into at least one to two years. Importantly, look out for lung complications, and the above stated higher risk profiles, and refer these patients quickly for further care.
Easier access to antiviral drugs and their responsible use and monitoring would help allay public fears of delay in treatment, but this should be tempered with care and not over-exuberance to dish out to one and all, the precious antiviral drug, just for prevention — this may be a very bad move which can inadvertently create a worse outcome of drug-resistant bugs.
However, in the light of the very quick deterioration of some young patients who have died, it might be prudent to use antiviral treatment earlier and more aggressively.
We look forward to the specific H1N1 vaccine, when it does come our way, probably towards the end of the year. In the meantime, encouraging those in the front-line, heart or lung patients and frequent travellers to have the seasonal flu vaccination is a useful adjunct to help stem the usual problems from other flu types.
9) Are we doing everything that should or needs to be done?
Yes, if you check what other nations are doing, we are doing relatively well. We are not overstating the dangers and we have been quite transparent on the possibilities of this pandemic. Earlier, many agencies and even the public and doctors have accused us of exaggerating the pandemic, and our response was dismissed as being too much, even over the top! Unfortunately, it was only when some deaths occur that many are now decrying that we have done too little!
Also if you are quite honest about it, just compare with the countries globally, and you will notice that no one health or government authority has got this right, spot on.
We are all learning about this novel flu pandemic, and each country's response is coloured by its past experiences. In Hong Kong, China, Vietnam, Singapore and Malaysia we have had the SARS outbreak, so we are necessarily more paranoid! Also here the experience is that flu does not usually cause death in our community, unlike the west where seasonal flu kills some hundreds of thousands every year!
So the fear factor for this H1N1 flu is not nearly as great in the West, although it is slowly sinking in that its contagiousness and infectivity is far greater, and fears of its reassortment to a more virulent mutant form are growing, into the so-called second and/or third wave of this pandemic, but we will not know until a year or so down the line.
10) Is the public in general doing enough to help in controlling the outbreak?
I think the public is now reasonably well-informed as to this H1N1 pandemic. Perhaps, they are too well-informed, that they have a fearful approach to this virus. But the proper thing is not too over-react and to panic, although I know this does sound easier said than done.
It is almost a certainty that this flu will spread within the community — in schools, universities, academies, factories, work places, offices, etc. WHO has projected that possibly some 20-30 per cent of the population worldwide will become infected by this novel flu bug, after studying various models of spread of past infections — the huge and very rapid spread worldwide is mainly due to air travel. While older flu pandemics took six months to extend to so many countries, this H1N1 flu did so in less than six weeks!
In the worst-case scenarios of course, this outbreak will be alarming — hospitalisations may be required for 100,000 up to 500,000 Malaysians, with perhaps as many as 5,000 to 27,000 infected patients (depending on the case fatality rate or either 0.1 to 0.5 per cent) succumbing to this illness.
But because we have been monitoring closely and containing the outbreak thus far, with heightened awareness and greater social responsibility, it is possible to ameliorate the infectivity, spread and fatality that will unfortunately accompany this pandemic... Just how successful we will be in limiting these adverse outcomes remains to be seen, but we can be hopeful.
How can the public help? First learn and acquire good personal hygiene. If sick, please be responsible and stay at home, even in your own room where possible, wear a face mask (a cheap three-ply surgical mask will do, because large droplet spread is the main danger). Do not go out, practice what is now known as social distancing (about three metres from anyone), and be socially responsible, don't go to public places and infect others — for young people this would be hard, but absolutely necessary — the spread is most rampant in this age group between 16 and 25 years.
When the illness does not go away after a few days or when you are deteriorating, get to the nearest hospital. Most importantly, be very aware and responsible!
Finally, keep abreast of all new developments, because these are evolving all the time. With keen awareness, prudent care, early detection and social responsibility, correct and prompt use of antiviral and other support medical care, and later mass specific vaccination, we can overcome this novel H1N1 flu! But it will take time, patience, public cooperation, much concerted effort and consume great resources.
Dr David KL Quek is president the Malaysian Medical Association.
Friday, July 31, 2009
CDC Issues H1N1 Vaccination Recommendations
From Medscape Medical News
Emma Hitt, PhD
July 30, 2009 (Atlanta, Georgia) — New H1N1 influenza vaccine recommendations from the Centers for Disease Control and Prevention (CDC) suggest priority distribution among 5 groups.
Recommended Target Groups
Anne Schuchat, MD, director of the National Center for Immunization and Respiratory Diseases with the CDC, announced that the Advisory Committee of Immunization Practices recommends that 5 target groups receive the vaccine:
•Pregnant women,
•household contacts of children who are younger than 6 months of age,
•healthcare workers and emergency medical services personnel,
•children and young people between the ages of 6 months and 24 years of age, and
•nonelderly adults with underlying risk conditions or medical conditions that increase their risk for complications from influenza.
The committee also addressed the issue of what to do in the event of a vaccine shortage and how to prioritize those groups who should receive the vaccine.
"In general, under most circumstances, we really ought to promote vaccine in all of these 5 focus groups, and...picking them or prioritizing some before others would not benefit the public," Dr. Schuchat said. The CDC's estimate of the target groups totals 159 million individuals, but "there's a lot of overlap in some of the groups...[it is] probably a lower number than that," she said.
"Just in Case" Prioritization Group
However, the Advisory Committee of Immunization Practices also proposed a priority group consisting of a much smaller group, about 41 million individuals, that should be vaccinated in the event of a shortage. These include
•Pregnant women,
•household contacts of children who are younger than 6 months of age,
•healthcare workers and emergency services personnel who have direct patient contact or direct contact with infectious substances,
•children between the ages of 6 months and 4 years of age, and
•children 5 to18 years of age who have underlying risk factors that put them at greater risk for complications of influenza.
According to Dr. Schuchat, the real operating assumption is that they will "go forward with the broader group," she said.
Seasonal Influenza Vaccine Remains Important
According to the CDC, the seasonal influenza vaccine remains very important. "Our assumption is that it is very likely [that seasonal influenza and H1N1 vaccines] can be given together," Dr. Schuchat told Medscape Infectious Diseases during the briefing. "There will be more data coming out...but it is likely they can be given at the same visit," she said. According to Dr. Schuchat, 2 doses of the vaccine will probably be needed, with 15 μg antigen/dose.
"The recommendations make sense on the basis of what we know about this virus," said John Bartlett, MD, chief of the Johns Hopkins University School of Medicine, Division of Infectious Diseases, Baltimore, Maryland.
"Of interest is the observation that persons over 64 years, a high priority for seasonal flu vaccine, are not included here," he told Medscape Infectious Diseases. "That decision is based on the curious observation that the people born before 1957 appear to be relatively well protected from infection or serious disease with this strain of H1N1 virus." According to Dr. Bartlett, it appears that a similar strain circulated before 1957, accounting for this protection; other comparable viruses also have circulated more recently.
"Pregnant women and young people seem to be especially susceptible to [the H1N1] influenza strain and also to bad outcomes when infected," he said. "But the elderly should get [the] seasonal flu vaccine, since they account for the vast majority of the 36,000 deaths attributed to seasonal influenza in the average season" he added. "In fact, most people should get seasonal flu vaccine. The current indications for that vaccine apply to about 80% of the US population."
Production a Concern
Dr. Schuchat noted that the production of the H1N1 vaccine could be unpredictable. "Right now, we are to on track, expecting vaccine doses in the fall," she said, adding that "exactly how many [doses will be available] exactly when will be tough to pinpoint."
"Production is a concern, since the novel H1N1 virus does not grow well in eggs, and 2 doses are likely to be necessary," said Dr. Bartlett. If the virus thrives in the fall in the Northern hemisphere, "it will be a challenge to be ready," he said.
Emma Hitt, PhD
July 30, 2009 (Atlanta, Georgia) — New H1N1 influenza vaccine recommendations from the Centers for Disease Control and Prevention (CDC) suggest priority distribution among 5 groups.
Recommended Target Groups
Anne Schuchat, MD, director of the National Center for Immunization and Respiratory Diseases with the CDC, announced that the Advisory Committee of Immunization Practices recommends that 5 target groups receive the vaccine:
•Pregnant women,
•household contacts of children who are younger than 6 months of age,
•healthcare workers and emergency medical services personnel,
•children and young people between the ages of 6 months and 24 years of age, and
•nonelderly adults with underlying risk conditions or medical conditions that increase their risk for complications from influenza.
The committee also addressed the issue of what to do in the event of a vaccine shortage and how to prioritize those groups who should receive the vaccine.
"In general, under most circumstances, we really ought to promote vaccine in all of these 5 focus groups, and...picking them or prioritizing some before others would not benefit the public," Dr. Schuchat said. The CDC's estimate of the target groups totals 159 million individuals, but "there's a lot of overlap in some of the groups...[it is] probably a lower number than that," she said.
"Just in Case" Prioritization Group
However, the Advisory Committee of Immunization Practices also proposed a priority group consisting of a much smaller group, about 41 million individuals, that should be vaccinated in the event of a shortage. These include
•Pregnant women,
•household contacts of children who are younger than 6 months of age,
•healthcare workers and emergency services personnel who have direct patient contact or direct contact with infectious substances,
•children between the ages of 6 months and 4 years of age, and
•children 5 to18 years of age who have underlying risk factors that put them at greater risk for complications of influenza.
According to Dr. Schuchat, the real operating assumption is that they will "go forward with the broader group," she said.
Seasonal Influenza Vaccine Remains Important
According to the CDC, the seasonal influenza vaccine remains very important. "Our assumption is that it is very likely [that seasonal influenza and H1N1 vaccines] can be given together," Dr. Schuchat told Medscape Infectious Diseases during the briefing. "There will be more data coming out...but it is likely they can be given at the same visit," she said. According to Dr. Schuchat, 2 doses of the vaccine will probably be needed, with 15 μg antigen/dose.
"The recommendations make sense on the basis of what we know about this virus," said John Bartlett, MD, chief of the Johns Hopkins University School of Medicine, Division of Infectious Diseases, Baltimore, Maryland.
"Of interest is the observation that persons over 64 years, a high priority for seasonal flu vaccine, are not included here," he told Medscape Infectious Diseases. "That decision is based on the curious observation that the people born before 1957 appear to be relatively well protected from infection or serious disease with this strain of H1N1 virus." According to Dr. Bartlett, it appears that a similar strain circulated before 1957, accounting for this protection; other comparable viruses also have circulated more recently.
"Pregnant women and young people seem to be especially susceptible to [the H1N1] influenza strain and also to bad outcomes when infected," he said. "But the elderly should get [the] seasonal flu vaccine, since they account for the vast majority of the 36,000 deaths attributed to seasonal influenza in the average season" he added. "In fact, most people should get seasonal flu vaccine. The current indications for that vaccine apply to about 80% of the US population."
Production a Concern
Dr. Schuchat noted that the production of the H1N1 vaccine could be unpredictable. "Right now, we are to on track, expecting vaccine doses in the fall," she said, adding that "exactly how many [doses will be available] exactly when will be tough to pinpoint."
"Production is a concern, since the novel H1N1 virus does not grow well in eggs, and 2 doses are likely to be necessary," said Dr. Bartlett. If the virus thrives in the fall in the Northern hemisphere, "it will be a challenge to be ready," he said.
Monday, July 27, 2009
Salt a Key Player in Resistant Hypertension
by Lisa Nainggolan
From Heartwire
July 21, 2009 (Brisbane, Australia) — The first study to evaluate the effects of a low-salt diet in patients with resistant hypertension has shown that this strategy reduced blood pressure far beyond expectations, suggesting that such patients are extremely sensitive to the BP-lowering effects of sodium reduction.
The findings indicate "that in patients with resistant hypertension, a low-salt diet may be more effective than increasing the number of antihypertensive medications," lead author Dr Eduardo Pimenta (Princess Alexandra Hospital, Brisbane, Australia) told heartwire .
As a result, patients with resistant hypertension should, if possible, be counselled by a dietician, and "as 75% of sodium comes from prepared foods, restaurant meals, etc, public-health strategies are needed to reduce sodium content."
In an accompanying editorial commentary [2], Dr Lawrence J Appel (Johns Hopkins University, Baltimore, MD) congratulates Pimenta and coauthors on the implementation of a "challenging but informative and likely influential study" that demonstrated "striking" results. However, the study was small--with only 12 participants--and there was only one week per feeding period, so "replication of the study is clearly warranted," says Appel.
Nevertheless, the research indicates that a "renewed and aggressive emphasis on lifestyle modification, specifically sodium reduction, is warranted in patients with resistant hypertension and uncontrolled BP," he states.
Logistical Difficulties Overcome
Pimenta explains that resistant hypertension--defined as patients with uncontrolled BP despite taking three or more medications--is a common problem, affecting an estimated 20% to 30% of those with hypertension, and its prevalence is increasing.
The effects of reducing dietary sodium on mild-to-moderate hypertension are well documented, and have shown a small BP reduction with a low-salt diet, he adds. But according to Pimenta there have been no previous studies evaluating the role of dietary salt in those with resistant hypertension.
He and his colleagues conducted a two-period, randomized, crossover feeding study that compared two levels of sodium intake--250 mmol (5700 mg) per day versus 50 mmol (1150 mg) per day--in 12 patients with resistant hypertension referred to the University of Alabama Hypertension Clinic, where Pimenta was a postdoctoral research fellow. The aim was to determine the effects of dietary sodium restriction on office and 24-hour ambulatory BP, and each feeding period lasted one week.
At baseline, the participants–-half of whom were black and 67% of whom were female--had a mean body mass index of 32.9 kg/m2 and a mean office BP of 145.8/83.9 mm Hg on an average of 3.4 antihypertensive medications.
Results Extend the Role of Sodium Reduction to Resistant Hypertension
Compared with the higher level of sodium intake, the lower level reduced mean office systolic BP by 22.7 mm Hg and office diastolic BP by 9.1 mm Hg. Reductions in daytime, nighttime, and 24-hour ambulatory BP were virtually identical to reductions in office BP.
Importantly, says Appel, "the extent of BP reduction vastly exceeds corresponding levels of BP reduction observed in [salt-reducing] trials of hypertensive individuals not on medication," for example, the participants with untreated hypertension in the Dietary Approaches to Stop Hypertension (DASH)-sodium study.
"In the context of other human research on dietary sodium intake and BP, which has focused almost exclusively on individuals who were on no or few antihypertensive medications, these results extend the role of sodium reduction to an important but understudied population," he states.
And he admits to being "surprised by the extent of the BP reduction," which he describes as "huge . . . roughly equivalent to adding two antihypertensive medications."
HCTZ Not the Best Choice of Diuretic for Resistant Hypertension
All of the participants were taking the diuretic hydrochlorothiazide (HCTZ), and both Appel and Pimenta say that in this setting, one might have expected an attenuated effect from dietary salt reduction, given that the patients were already on volume-reducing therapy.
But the pattern of findings suggests a volume-expanded state on conventional doses of HCTZ, indicating that the diuretic type and dose recommended by general hypertension guidelines "may not be as effective in patients with resistant hypertension [as in] mild-to-moderate hypertensives," Pimenta says.
He suggests that chlorthalidone, "which reduces BP more effectively and has a longer duration of action than HCTZ," should be used in resistant hypertension patients, and Appel concurs.
A Clear Target for Intervention
"Another remarkable, perhaps expected, finding was the high baseline sodium intake" of the participants, "measured when [they] were eating food that they prepared or selected," notes Appel. The mean 24-hour dietary sodium excretion at baseline--194.7 mmol (4470 mg) per day--was nearly double the recommended upper limit of daily sodium for the general population, and nearly triple the corresponding daily limit for people with hypertension, he observes.
"Although one might be discouraged by the excessive levels of sodium intake in this high-risk population, such levels also provide a clear opportunity for intervention," he stresses. But a "critical issue" is how to accomplish this. A combination of individual-based counselling (eg, from a dietician) and public-health strategies to reduce the sodium content of the food supply at a population level are needed, he believes.
"It will be impossible to reach an intake of 50 mmol per day without a major reduction in the sodium content of commercially prepared foods. Outside the arcane environment of the feeding study, a sodium intake of around 50 mmol per day is rare in the US," where, even with intensive behavioral counselling focusing exclusively on sodium reduction, mean achieved levels of sodium intake are typically about 100 mmol (2300 mg) per day, he observes.
In the meantime, doctors managing patients with resistant hypertension should use chlorthalidone rather than HCTZ, should reinforce key messages related to the reduction of dietary sodium intake, and should refer the patient, if possible, to a dietician. In addition, physicians need to "advocate for policy changes that lead to a reduced sodium content of commercially prepared foods," Appel concludes.
From Heartwire
July 21, 2009 (Brisbane, Australia) — The first study to evaluate the effects of a low-salt diet in patients with resistant hypertension has shown that this strategy reduced blood pressure far beyond expectations, suggesting that such patients are extremely sensitive to the BP-lowering effects of sodium reduction.
The findings indicate "that in patients with resistant hypertension, a low-salt diet may be more effective than increasing the number of antihypertensive medications," lead author Dr Eduardo Pimenta (Princess Alexandra Hospital, Brisbane, Australia) told heartwire .
As a result, patients with resistant hypertension should, if possible, be counselled by a dietician, and "as 75% of sodium comes from prepared foods, restaurant meals, etc, public-health strategies are needed to reduce sodium content."
In an accompanying editorial commentary [2], Dr Lawrence J Appel (Johns Hopkins University, Baltimore, MD) congratulates Pimenta and coauthors on the implementation of a "challenging but informative and likely influential study" that demonstrated "striking" results. However, the study was small--with only 12 participants--and there was only one week per feeding period, so "replication of the study is clearly warranted," says Appel.
Nevertheless, the research indicates that a "renewed and aggressive emphasis on lifestyle modification, specifically sodium reduction, is warranted in patients with resistant hypertension and uncontrolled BP," he states.
Logistical Difficulties Overcome
Pimenta explains that resistant hypertension--defined as patients with uncontrolled BP despite taking three or more medications--is a common problem, affecting an estimated 20% to 30% of those with hypertension, and its prevalence is increasing.
The effects of reducing dietary sodium on mild-to-moderate hypertension are well documented, and have shown a small BP reduction with a low-salt diet, he adds. But according to Pimenta there have been no previous studies evaluating the role of dietary salt in those with resistant hypertension.
He and his colleagues conducted a two-period, randomized, crossover feeding study that compared two levels of sodium intake--250 mmol (5700 mg) per day versus 50 mmol (1150 mg) per day--in 12 patients with resistant hypertension referred to the University of Alabama Hypertension Clinic, where Pimenta was a postdoctoral research fellow. The aim was to determine the effects of dietary sodium restriction on office and 24-hour ambulatory BP, and each feeding period lasted one week.
At baseline, the participants–-half of whom were black and 67% of whom were female--had a mean body mass index of 32.9 kg/m2 and a mean office BP of 145.8/83.9 mm Hg on an average of 3.4 antihypertensive medications.
Results Extend the Role of Sodium Reduction to Resistant Hypertension
Compared with the higher level of sodium intake, the lower level reduced mean office systolic BP by 22.7 mm Hg and office diastolic BP by 9.1 mm Hg. Reductions in daytime, nighttime, and 24-hour ambulatory BP were virtually identical to reductions in office BP.
Importantly, says Appel, "the extent of BP reduction vastly exceeds corresponding levels of BP reduction observed in [salt-reducing] trials of hypertensive individuals not on medication," for example, the participants with untreated hypertension in the Dietary Approaches to Stop Hypertension (DASH)-sodium study.
"In the context of other human research on dietary sodium intake and BP, which has focused almost exclusively on individuals who were on no or few antihypertensive medications, these results extend the role of sodium reduction to an important but understudied population," he states.
And he admits to being "surprised by the extent of the BP reduction," which he describes as "huge . . . roughly equivalent to adding two antihypertensive medications."
HCTZ Not the Best Choice of Diuretic for Resistant Hypertension
All of the participants were taking the diuretic hydrochlorothiazide (HCTZ), and both Appel and Pimenta say that in this setting, one might have expected an attenuated effect from dietary salt reduction, given that the patients were already on volume-reducing therapy.
But the pattern of findings suggests a volume-expanded state on conventional doses of HCTZ, indicating that the diuretic type and dose recommended by general hypertension guidelines "may not be as effective in patients with resistant hypertension [as in] mild-to-moderate hypertensives," Pimenta says.
He suggests that chlorthalidone, "which reduces BP more effectively and has a longer duration of action than HCTZ," should be used in resistant hypertension patients, and Appel concurs.
A Clear Target for Intervention
"Another remarkable, perhaps expected, finding was the high baseline sodium intake" of the participants, "measured when [they] were eating food that they prepared or selected," notes Appel. The mean 24-hour dietary sodium excretion at baseline--194.7 mmol (4470 mg) per day--was nearly double the recommended upper limit of daily sodium for the general population, and nearly triple the corresponding daily limit for people with hypertension, he observes.
"Although one might be discouraged by the excessive levels of sodium intake in this high-risk population, such levels also provide a clear opportunity for intervention," he stresses. But a "critical issue" is how to accomplish this. A combination of individual-based counselling (eg, from a dietician) and public-health strategies to reduce the sodium content of the food supply at a population level are needed, he believes.
"It will be impossible to reach an intake of 50 mmol per day without a major reduction in the sodium content of commercially prepared foods. Outside the arcane environment of the feeding study, a sodium intake of around 50 mmol per day is rare in the US," where, even with intensive behavioral counselling focusing exclusively on sodium reduction, mean achieved levels of sodium intake are typically about 100 mmol (2300 mg) per day, he observes.
In the meantime, doctors managing patients with resistant hypertension should use chlorthalidone rather than HCTZ, should reinforce key messages related to the reduction of dietary sodium intake, and should refer the patient, if possible, to a dietician. In addition, physicians need to "advocate for policy changes that lead to a reduced sodium content of commercially prepared foods," Appel concludes.
Pesticide Exposure Linked to Parkinson's, Alzheimer's Disease
Pauline Anderson
From Medscape Medical News
July 23, 2009 — Two new studies have added to the growing body of evidence pointing to a link between pesticide exposure and the risk for neurological disorders.
One study linked high levels of an organochlorine pesticide called beta-hexachlorocyclohexane (beta-HCH) to an increased risk for Parkinson's disease (PD), while another showed an association between agricultural pesticide exposure and dementia, including Alzheimer's disease (AD).
The first study, published in the July issue of Archives of Neurology, included 50 patients with PD treated at the Clinical Center for Movement Disorders at the University of Texas (UT) Southwestern Medical Center at Dallas and 20 patients with AD and 43 controls from the Alzheimer's Disease Center at the UT Southwestern Medical Center.
Using blood samples, researchers tested for 16 organochlorine pesticides, including beta-HCH. The specific pesticides included in the study were chosen on the basis of how often they show up in environmental samples.
Banned During the 1970s
Used extensively across the United States beginning in the 1950s, organochlorine pesticides were banned during the 1970s because of concerns about their bioaccumulation and toxic effects. Animal studies show that these pesticides are neurotoxic, cause oxidative stress, and damage the brain's dopaminergic system.
The study, 1 of the largest of its kind to date and perhaps the first to link a particular pesticide with PD, found that 9 of the 16 pesticides tested were present in study subjects. The pesticide found most often was p.pDDE. It was detected in 100% of the AD patients, 72% of the PD patients, and 86% of the controls.
Beta-HCH was also present in elevated levels in some patients. It was detected most often in the serum of patients with PD: 38 of 50 (76%) compared with 17 of 43 (40%) in controls and 6 of 20 (30%) in patients with AD.
Compared with controls, the odds ratio for PD risk associated with beta-HCH levels was 4.39. The median level of beta-HCH was significantly higher in patients with PD (median, 0.36 ng/mL) compared with controls and patients with AD (median, 0 ng/mL for both).
This pesticide was widely used during the 1960s and 1970s, particularly on cotton plants, said Dr. Richardson. Although banned as a pesticide more than 30 years ago, traces of beta-HCH can still be found in water and soil.
Factors That Alter Risk
Researchers found beta-HCH in samples of some controls, although generally at lower levels than in patients with PD. This, said Dr. Richardson, suggests that other factors may interact with beta-HCH exposure to alter the risk for PD. While caffeine consumption and cigarette smoking have been associated with a decreased risk for PD, Dr. Richardson said it is most likely genetic factors that determine risk.
Blood samples from 18 of the PD patients taken 5 years apart showed that mean levels of beta-HCH did not change significantly over time. "This suggested that there may be some people who, because of their genetics, may not get rid of this pesticide as well as others, and these people may be the ones who are at risk for Parkinson's," said Dr. Richardson. "That's something we're very interested in trying to determine."
The authors noted that since 12 PD patients did not have detectable levels of beta-HCH, exposure to this pesticide may contribute to PD in only a subset of patients.
Exposure Through Food
Dr. Richardson speculated that most of the pesticide exposure is through food consumption. He noted that other studies have found a high rate of PD among populations that consume large quantities of fish and whale meat.
The second study, presented earlier this month at the Alzheimer's Association 2009 International Conference on Alzheimer's Disease (ICAD 2009), in Vienna, Austria, was part of a longitudinal cohort study of memory in aging among residents of Cache County, Utah, aged 65 years and older. These residents were asked detailed questions about their pesticide exposure.
Of 4012 study participants who had no dementia at baseline in 1995, 743 reported some exposure to pesticides, said Kathleen M. Hayden, PhD, assistant professor of psychiatry and behavioral sciences at Duke University, in Durham, North Carolina, who presented the findings.
Pesticides Only 1 Piece of Dementia Puzzle
Unlike patients in the first study, most of the exposure to pesticides in this analysis was likely through farming. Cache County is 1 of the primary agricultural regions in Utah, leading the state in barley production, said Dr. Hayden. Pesticide exposure of some study participants extended to 12 or more years.
Over 7 years of follow-up, 412 patients were identified with incident dementia, most with AD. Of these, 85 had reported exposure to pesticides.
After adjusting for age, sex, education, and APOE genotype, researchers determined that residents exposed to pesticides had an increased risk for dementia (OR, 1.56; 95% CI, 1.16 – 2.09). The OR for AD was 1.53 (95% CI, 1.02 – 2.26).
Although the study was not ideal (exposure classifications were less than perfect, for example), its strengths were that it had a relatively large sample size, the residents were followed for several years, and they underwent regular diagnostic assessments, said Dr. Hayden.
"It's definitely not a definitive study, but it does add to a growing body of literature linking pesticides to dementia," she said.
Pesticide exposure is likely only 1 piece of the AD puzzle. "Pesticides represent only 1 environmental factor; there are many environmental factors that may increase risk, and some that decrease risk," said Dr. Hayden. "These probably combine with genetic risk factors that we know about and others we have yet to discover."
Arch Neurol. 2009;66:870-875. Abstract
From Medscape Medical News
July 23, 2009 — Two new studies have added to the growing body of evidence pointing to a link between pesticide exposure and the risk for neurological disorders.
One study linked high levels of an organochlorine pesticide called beta-hexachlorocyclohexane (beta-HCH) to an increased risk for Parkinson's disease (PD), while another showed an association between agricultural pesticide exposure and dementia, including Alzheimer's disease (AD).
The first study, published in the July issue of Archives of Neurology, included 50 patients with PD treated at the Clinical Center for Movement Disorders at the University of Texas (UT) Southwestern Medical Center at Dallas and 20 patients with AD and 43 controls from the Alzheimer's Disease Center at the UT Southwestern Medical Center.
Using blood samples, researchers tested for 16 organochlorine pesticides, including beta-HCH. The specific pesticides included in the study were chosen on the basis of how often they show up in environmental samples.
Banned During the 1970s
Used extensively across the United States beginning in the 1950s, organochlorine pesticides were banned during the 1970s because of concerns about their bioaccumulation and toxic effects. Animal studies show that these pesticides are neurotoxic, cause oxidative stress, and damage the brain's dopaminergic system.
The study, 1 of the largest of its kind to date and perhaps the first to link a particular pesticide with PD, found that 9 of the 16 pesticides tested were present in study subjects. The pesticide found most often was p.pDDE. It was detected in 100% of the AD patients, 72% of the PD patients, and 86% of the controls.
Beta-HCH was also present in elevated levels in some patients. It was detected most often in the serum of patients with PD: 38 of 50 (76%) compared with 17 of 43 (40%) in controls and 6 of 20 (30%) in patients with AD.
Compared with controls, the odds ratio for PD risk associated with beta-HCH levels was 4.39. The median level of beta-HCH was significantly higher in patients with PD (median, 0.36 ng/mL) compared with controls and patients with AD (median, 0 ng/mL for both).
This pesticide was widely used during the 1960s and 1970s, particularly on cotton plants, said Dr. Richardson. Although banned as a pesticide more than 30 years ago, traces of beta-HCH can still be found in water and soil.
Factors That Alter Risk
Researchers found beta-HCH in samples of some controls, although generally at lower levels than in patients with PD. This, said Dr. Richardson, suggests that other factors may interact with beta-HCH exposure to alter the risk for PD. While caffeine consumption and cigarette smoking have been associated with a decreased risk for PD, Dr. Richardson said it is most likely genetic factors that determine risk.
Blood samples from 18 of the PD patients taken 5 years apart showed that mean levels of beta-HCH did not change significantly over time. "This suggested that there may be some people who, because of their genetics, may not get rid of this pesticide as well as others, and these people may be the ones who are at risk for Parkinson's," said Dr. Richardson. "That's something we're very interested in trying to determine."
The authors noted that since 12 PD patients did not have detectable levels of beta-HCH, exposure to this pesticide may contribute to PD in only a subset of patients.
Exposure Through Food
Dr. Richardson speculated that most of the pesticide exposure is through food consumption. He noted that other studies have found a high rate of PD among populations that consume large quantities of fish and whale meat.
The second study, presented earlier this month at the Alzheimer's Association 2009 International Conference on Alzheimer's Disease (ICAD 2009), in Vienna, Austria, was part of a longitudinal cohort study of memory in aging among residents of Cache County, Utah, aged 65 years and older. These residents were asked detailed questions about their pesticide exposure.
Of 4012 study participants who had no dementia at baseline in 1995, 743 reported some exposure to pesticides, said Kathleen M. Hayden, PhD, assistant professor of psychiatry and behavioral sciences at Duke University, in Durham, North Carolina, who presented the findings.
Pesticides Only 1 Piece of Dementia Puzzle
Unlike patients in the first study, most of the exposure to pesticides in this analysis was likely through farming. Cache County is 1 of the primary agricultural regions in Utah, leading the state in barley production, said Dr. Hayden. Pesticide exposure of some study participants extended to 12 or more years.
Over 7 years of follow-up, 412 patients were identified with incident dementia, most with AD. Of these, 85 had reported exposure to pesticides.
After adjusting for age, sex, education, and APOE genotype, researchers determined that residents exposed to pesticides had an increased risk for dementia (OR, 1.56; 95% CI, 1.16 – 2.09). The OR for AD was 1.53 (95% CI, 1.02 – 2.26).
Although the study was not ideal (exposure classifications were less than perfect, for example), its strengths were that it had a relatively large sample size, the residents were followed for several years, and they underwent regular diagnostic assessments, said Dr. Hayden.
"It's definitely not a definitive study, but it does add to a growing body of literature linking pesticides to dementia," she said.
Pesticide exposure is likely only 1 piece of the AD puzzle. "Pesticides represent only 1 environmental factor; there are many environmental factors that may increase risk, and some that decrease risk," said Dr. Hayden. "These probably combine with genetic risk factors that we know about and others we have yet to discover."
Arch Neurol. 2009;66:870-875. Abstract
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