Men That Smoke At Risk for Rapid Cognitive Decline
Smoking is a known risk factor for many health ills including dementia. But as with other conditions, there is also a difference among age of onset and level of decline based on factors such as age or gender. Men who smoke in middle age appear to suffer a more rapid cognitive decline than peers who have never smoked or who have been ex-smokers for at least 10 years.
In the Archives of General Psychiatry, Severine Sabia PhD of the University College London’s Department of Epidemiology and Public Health published findings from data collected from over 5,000 men and just over 2,000 women. The subjects were employees of the British Civil Service who had participated in the Whitehall II study which investigated social determinants of health, specifically the prevalence of cardiorespiratory disease.
Over the course of 25 years, the subjects reported on their smoking status six times and had cognitive function assessed three times at certain age ranges. The evaluation consisted of five tests of memory, vocabulary, and reasoning skills.
The team found that male smokers exhibited faster mental decline than non-smokers and that the decline was more pronounced the more cigarettes a subject smoked. Current smoking conferred the equivalent of 10 years of aging on cognition, noted Dr. Sabia. The executive function (complex thinking skills such as memory, attention, and problem solving) of the average 50-year-old male smoker, for example, was estimated to be about that of a 60-year-old man who had never smoked. Even those who smoked intermittently showed similar cognitive decline rates as those who were regular smokers.
The researchers suggest that the cause was likely due to vascular or lung damage, two health conditions linked to dementia. However, other factors could also be involved, such as the men who smoked often had greater alcohol consumption as well.
Ex-smokers, those who had ceased smoking cigarettes at least 10 years before the first assessment took place (average age 56 years) did not show a significant increase in cognitive decline. The women in the study also did not show as rapid of decline, perhaps because they tended to smoke less, hypothesized the authors, and for fewer years.
"It is increasingly recognized that age-related cognitive pathologies such as dementia result from long-term processes, perhaps beginning as long as 20 to 30 years before the clinical diagnosis of dementia. Our study illustrates the importance of examining risk factors for cognitive decline much earlier in the life course," concludes Dr. Sabia.
Sabia S, et al "Impact of smoking on cognitive decline in early old age: The Whitehall II Cohort study" Arch Gen Psychiatry 2012; DOI:10.1001/archgenpsychiatry.2011.2016.
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