From Medscape Medical News
Nancy Fowler Larson
December 20, 2010 — Eating a healthy diet, exercising, and abstaining from smoking may reduce the risk for early age-related macular degeneration (AMD), according to a study published online December 13 in the Archives of Ophthalmology.
The macula, a portion of the retina responsible for central vision, degenerates with age. The progression can result in AMD, a deterioration of the macula's photoreceptors. Treatment is limited and costly, and the cumulative cost will grow as the population ages.
Those affected by AMD experience a substantial decline in independent function.
"The loss of central vision associated with advanced AMD diminishes the ability to see and recognize other people's faces and to read fine print such as that in newspapers and on pill bottles and food packages," write Julie A. Mares, PhD, from the Departments of Ophthalmology and Visual Sciences, at the University of Wisconsin, in Madison, and colleagues.
Smoking is associated with an increased risk, and chronic conditions including cardiovascular disease, diabetes, hypertension, and obesity, all of which can be managed through diet and other lifestyle adjustments, seem more common in patients with AMD. Adopting healthier habits has been linked to a reduced incidence of AMD.
To further explore those relationships, the investigators used data from the Carotenoids in Age-Related Eye Disease Study (CAREDS), part of the 1994-1998 Women's Health Initiative Observational Study. The 1313 participants ranged in age from 55 to 74 years.
The participants' answers to a food frequency questionnaire were used to produce scores on a modified 2005 Healthy Eating Index. Requirements for a healthy daily diet included 3.5 servings of fruit and vegetables; 2.3 servings of dairy; 2.7 ounces of meat, poultry, fish, beans, or eggs; and 3.5 serving of grain, including 1 whole-grain item.
Exercise habits and lifelong smoking history were also recorded. The presence of AMD in 202 participants, 94% of whom had early-stage degeneration, was determined an average of 6 years later through stereoscopic fundus photographs.
Overall Healthier Lifestyle May Reduce AMD Risk 3-Fold
The results demonstrated a significant association between early AMD and diet, exercise, and overall healthy habits, as follows:
* With use of multivariate models, women with highest-quintile 2005 Healthy Eating Index diet scores vs those with the lowest quintile showed a 46% reduction in the odds for early AMD (multivariate-adjusted odds ratio [OR], 0.54; 95% confidence interval [CI], 0.33 - 0.88).
* Those in the highest quintile for physical activity demonstrated a 2-fold decrease in multivariate-adjusted odds for AMD (OR, 0.46; 95% CI, 0.27 - 0.78; P for trend = .002).
* Smoking for long or short intervals had only a slight positive association with AMD (P = .07).
* Nonsmokers who also ate the healthiest diets and were the most active (5% of participants) reduced their odds for AMD by 71% vs those with high-risk scores (P < .001).
"Adopting these healthy habits may markedly lower the prevalence of early AMD, the number of people who develop advanced AMD in their lifetime, and health care costs associated with treatment for this condition," the study authors write.
Several limitations to the study were noted:
* The primarily white, female population hinders the generalization of findings to men and to those of Hispanic, African, and Asian ethnicities.
* Interrelated habits were not independently evaluated.
* Consideration was not given to high-risk genotypes for AMD.
"In our study, having a family history of AMD did not modify the association of a healthy diet or lifestyle to AMD, but genotyping will better characterize a person's susceptibility for the disease and improve the ability to examine the possibility that diet and lifestyle modify genetic risk," the study authors write.
Arch Ophthalmol. Published online December 13, 2010. Abstract
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