Smoking increases risk of memory decline

Smoking Appears Linked With Risk for Poor Memory in Middle Age CME/CE

News Author: Marlene Busko
CME Author: Penny Murata, MD

June 12, 2008 — Smoking is linked to an increased risk for memory deficit and cognitive decline in middle age in an analysis based on data from Whitehall II, a large, prospective cohort study.

The findings by Séverine Sabia, MSc, at the Institut National de la Santé et de la Recherche Médicale, in Villejuif, France, and colleagues, are published in the June 9 issue of the Archives of Internal Medicine.

Compared with study participants who had never smoked, after adjustment for other confounding factors, smokers had a 37% increased risk of having scores in the lowest quintile on a memory test (they were more likely to recall less than 5 of 20 words), Ms. Sabia told Medscape Psychiatry.

Cognitive Decline in Middle Age

"This risk is quite important considering that we are only in middle-age when cognitive decline is just starting," she noted. Evidence of this association at this age could support the hypothesis that smoking is involved in the pathogenesis of preclinical cognitive deficit and decline, which is a risk factor for later dementia, she added.

With the aging population and the projected increases in older adults with dementia, it is important to identify modifiable risk factors, she noted. "Our results suggest that smoking had an adverse effect on cognitive function in midlife, [but] 10 years after smoking cessation, there was little adverse effect of smoking on cognition," she added. "Thus, public health messages should target smokers at all ages."

A recent meta-analysis concluded that smoking is a risk factor for dementia, the group writes, adding that it is problematic to study the link between smoking and cognition (thinking, learning, and memory) in older people because many study participants do not return for follow-up visits, or they die from smoking-related diseases.

At the same time, there is increasing evidence that midlife risk factors play a role in later dementia.

A meta-analysis by Anstey and colleagues in the August 15, 2007, issue of the American Journal of Epidemiology found that smoking is a risk factor for dementia. However, as noted by Kukull in the February 1, 2001, issue of Biological Psychiatry, the effects of smoking might be difficult to determine because of attrition and smoking-related mortality before the diagnosis of dementia. However, the effects of smoking on cognitive ability before the onset of dementia could be examined.

In the Whitehall II study described by Marmot and colleagues in the June 8, 1991, issue of The Lancet, civil servants were recruited in 1985 to assess the link between socioeconomic factors and health. This study uses the Whitehall II database to examine whether smoking history is associated with cognitive function in middle-aged adults and to assess the risk for death and participation in cognitive tests in those who smoke.

After adjustment for age, sex, sociodemographics, and health behaviors, middle-aged smokers vs never-smokers are more likely to have cognitive deficits in memory and decline in reasoning skills. Long-term ex-smokers vs never-smokers are less likely to have deficits in memory, vocabulary, and fluency.

Middle-aged adults who smoke have a higher risk for death or nonparticipation in cognitive tests

http://cme.medscape.com/viewarticle/575940?sssdmh=dm1.474949&src=nldne