Smoking Speeds UpMemory Loss in Middle Age
By Alison McCook
NEW YORK (Reuters Health) - Cigarette smokers who continue the habit through middle age may see their memory suffer as a result, according to new study findings released Wednesday.
UK researchers found that, from their 40s to their 50s, smokers showed a faster decline in their scores on tests of word memory, relative to non-smokers.
Furthermore, people who smoked in their 40s did worse on tests that measure how fast they could pick out certain letters from a page than non-smokers of the same age, the authors write in the American Journal of Public Health.
The relationship between smoking and memory loss appeared strongest in people who smoked more than 20 cigarettes each day, and persisted even when the authors controlled for the influence of socioeconomic status, gender and a range of medical conditions.
Just why smoking may speed up age-related memory loss is not yet clear, study author Dr. Marcus Richards of University College London told Reuters Health.
He said that he and his colleagues suspected that smoking may accelerate memory loss by increasing the risk of high blood pressure, which can damage the brain. However, the relationship between smoking and brain functioning may be slightly more complicated, Richards said.
"Our results for memory still held up after taking blood pressure into account, but smoking could have been causing changes in the brain's blood supply that we were not able to measure," he said.
Alternatively, chemicals in cigarette smoke could also damage the brain directly, Richards added.
Whatever the reasons for why smoking accelerates memory loss, the message from these results should be clear, Richards said.
"This is yet another reason to quit smoking," he said. "If you can't, then cut down as much as you can."
During the study, Richards and his team reviewed information collected from 5,362 people born in 1946. Study participants were contacted 21 times by the time they turned 53.
Researchers measured people's mental functioning via a series of tests. In one test, which looked at verbal memory, the investigators showed people 15 words for two seconds each, then asked them to write down as many as they could remember.
During tests of speed and concentration, people had to look for and cross out as many Ps and Ws they could find in a page of other letters within one minute.
Although smokers in their 40s performed just as well as non-smokers in the verbal memory tests, puffers' performance deteriorated much faster from their 40s to their 50s.
And people who said they smoked while in their 40s scored worse during speed tests conducted in their 40s than non-smokers.
But the findings also suggest that quitting may help, for the researchers discovered that people who stopped smoking before age 53, and especially those who stopped before age 43, tended to exhibit a slower decline in memory.
"Our results suggest that quitting may slow down the negative impact of smoking on cognitive function," Richards said.
SOURCE: American Journal of Public Health 2003;93.
Copyright © 2003 Reuters Limited. All rights reserved.
June 2003, Vol 93, No. 6 | American Journal of Public Health 994-998
© 2003 American Public Health Association
Cigarette Smoking and Cognitive Decline in Midlife: Evidence From a Prospective Birth Cohort Study
Marcus Richards, PhD, Martin J. Jarvis, DSc, Neil Thompson, BSc and Michael E. J. Wadsworth, PhD
Marcus Richards, Neil Thompson, and Michael E. J. Wadsworth are with the Medical Research Council, National Survey of Health and Development, University College London, London, England. Martin J. Jarvis is with the Cancer Research UK Health Behaviour Unit, University College London.
Correspondence: Requests for reprints should be sent to Marcus Richards, PhD, MRC National Survey of Health and Development, Royal Free and University College London Medical School, University College London, Department of Epidemiology and Public Health, 1-19 Torrington Pl, London WC1E 6BT, England (e-mail: firstname.lastname@example.org).
Objectives. The authors investigated the effects of cigarette smoking on midlife cognitive performance.
Methods. Multiple regression was used to test the association between cigarette smoking and changes in cognitive test scores among male and female members of the British 1946 birth cohort aged between 43 and 53 years.
Results. Smoking was associated with faster declines in verbal memory and with slower visual search speeds. These effects were largely accounted for by individuals who smoked more than 20 cigarettes per day and were independent of sex, socioeconomic status, previous (adolescent) cognitive ability, and a range of health indicators.
Conclusions. The present results show that heavy smoking is associated with cognitive impairment and decline in midlife. Smokers who survive into later life may be at risk of clinically significant cognitive declines.