| Smoking increases the rate of cognitive decline in elderly people up to five-fold compared with peers who never smoked Smoking significantly accelerates the rate of cognitive decline in the elderly, according to a large, multi-center study published in the March 23rd issue of Neurology. The rate of decline on average was five-fold was higher per year in current smokers than those who never smoked. Researchers in several European countries studied smoking habits and change in cognitive function in a group of 9,209 non-demented men and women aged 65 years and older over an average of 2.3 years. Cognitive function was screened with a series of questions and tests called the Mini-Mental State Examination. Among those who never smoked (41 percent), scores declined 0.03 points per year. The score for current smokers (22 percent) declined 0.16 points per year. Former smokers (37 percent) had a decrease that was intermediate in degree, 0.06 points per year. “On the individual level, a small difference in Mini-Mental State Examination score has little meaning,” said study author Alewijn Ott, MD. “On the group level, rates of change are more informative and show that smoking has an impact on cognitive function in the elderly.” Greater cognitive decline occurred with higher cigarette pack-year exposure, a calculation involving the number of years someone has smoked and the reported average daily number of cigarettes. This was significant mainly for former smokers and not the current smokers, perhaps due to lower numbers of current smokers in the study and greater measurement error in this group, Ott noted. On the examination, 30 points is the maximum score, representing highest cognitive function. A score of 24 points or fewer may imply an early stage of dementia, Ott said. The average score of the study group was 27.4 at baseline and 27.2 after follow-up. A family history of dementia did not influence the greater decline in scores in smokers. Smoking could affect cognitive function through various mechanisms. Chronic tobacco use causes atherosclerosis and hypertension. These, and other effects of smoking, increase the risk of stroke and small, silent brain infarctions, according to Ott. “More in-depth studies are needed to
verify if these or other factors are responsible for greater cognitive
decline in smokers,” said Ott. |