Smoking Speeds Dementia, Alzheimer's Disease

Smokers Decline Up to Five Times Faster Than Nonsmokers

From the WebMD Archives

March 22, 2004 -- Smokers have faster mental decline in elderly years -- up to fivefold faster, a new study shows.

Only a few studies have looked at this link between smoking and mental function in elderly people who don't have dementia or Alzheimer's disease. In recent studies, researchers have found a significantly increased risk of both dementia and Alzheimer's disease among smokers.

Smoking likely puts into effect a vicious cycle of artery damage, clotting, and increased risk of stroke causing mental decline, writes researcher A. Ott, MD, a medical microbiologist with Erasmus University Medical Centre in the Netherlands.

Ott's study appears in this week's issue of the journal Neurology.

The study involves 9,200 men and women over age 65, who were interviewed in their homes about their health and lifestyle, and who took tests measuring their mental function -- these tests are standard measurement used to detect mental impairment in the elderly. They re-took the tests two years later.

Among participants:

  • 5% had a history of stroke
  • 14% had a history of heart attack
  • 93% of men smoked, compared with 71% of women
  • 84% of men had ever smoked, compared with 39% of women

When results of their mental tests scores were compared with smoking data, the results were:

  • Former smokers had 0.03 point per year greater decline in scores compared with never smokers.
  • Current smokers had 0.13 points greater decline per year in scores compared with never smokers.

The average yearly decline in mental test scores for never smokers was 0.03 points per year.


  • Higher rates of mental decline were found in men and in women -- and in persons with or without a family history of dementia or Alzheimer's disease.
  • The number of years a person smoked dramatically increased their rate of mental decline.

Although the study is quite large, there are drawbacks. Physical disability and emotional- or concentration-related problems could have made the mental function tests difficult for some, Ott points out.

Those who participated in both series of tests were likely the healthier people. Also, some people may have inaccurately reported their smoking habits, Ott explains.

Nevertheless, the study provides substantial evidence that chronic tobacco use is harmful to the brain and speeds up onset of Alzheimer's disease.

SOURCE: Ott, A. Neurology, March 23, 2004; vol 62: pp 920-924.