Dementia Associated with Heavy Smoking in Midlife

Studies of smoking and dementia risk have yielded mixed results: Some data suggest that the risk for neurodegenerative illness is reduced by smoking, whereas other data suggest a positive correlation between amount of cigarette smoking and risk for Alzheimer disease (AD). In this retrospective analysis of prospectively collected data, more than 20,000 adults completed a survey regarding smoking habits between ages 50 and 60. Approximately 20 years later, they were assessed for dementia; more than 5000 of them received diagnoses of dementia by neurologists, neuropsychologists, or internists.

Compared with nonsmokers, those who reported heavy smoking (≥2 packs of cigarettes per day) in midlife demonstrated an elevated risk for later dementia d…