March 22, 2004
If you needed still another reason to quit smoking cigarettes, here's another: the habit appears to speed up mental decline as you age. Older men and women who smoked showed greater decline in memory than those who had never smoked, according to findings from a large study conducted at several European medical centers.
Researchers in Europe gave a popular memory test called the Mini-Mental State Exam (MMSE) to more than 9,000 seniors aged 65 and up. The test asks a series of questions that require people to recall lists of various items. A total of 30 is considered a perfect score on the MMSE, a sign of a very sharp memory. A score of 24 or below, on the other hand, suggests someone is having memory problems and may be suffering from the early stages of Alzheimer's disease. None of the seniors in the current study had Alzheimer's or other signs of dementia.
Study participants were asked about their smoking habits, and memory tests were repeated periodically for about two and a half years. Those seniors who had never smoked showed mental declines of 0.03 points per year in test performance during that time. In contrast, current smokers had five times more mental decline, or 0.16 points per year. Former smokers showed declines of about 0.06 points a year; the more packs per day they had smoked in the past, the more likely they were to show signs of accelerated mental decline. These changes in test scores are said to be "significant" because statistical tests show that they are unlikely to have occurred by chance. However, the changes themselves are small, making it difficult to know how they will affect the way people function in everyday life.
Although these numbers are small and the MMSE is an inexact test, the general trends indicate that smoking is bad for the memory as we age. In addition to lung cancer, smoking has been linked to high blood pressure, heart disease and strokes. Smoking may also damage blood vessels in the brain, which could contribute to mental decline.
Some earlier scientific reports suggested that nicotine and other substances in cigarette smoke may actually help protect against the mind-robbing ravages of Alzheimer's disease. However, other studies have linked smoking to an increased risk of dementia.
This study is one of the most rigorous to date to look at smoking in seniors who do not have Alzheimer's or memory impairment. Those who smoked, the results suggest, were more likely to do less well on memory tests than those who had never smoked or quit smoking. If you smoke, the study offers one more good reason to kick the habit.
The study appeared in the March 23, 2004 issue of Neurology, a medical journal for physicians.
A. Ott, K. Andersen, M.E. Dewey, et al: "Effect of smoking on global cognitive function in nondemented elderly." Neurology 2004;62:920-924.