Heavy smoking in middle age may more than double the risk of Alzheimer's disease later in life, according to a large population-based study.
The prospective cohort study of more than 21,000 people found that those who smoked more than two packs a day developed dementia of any kind twice as often as nonsmokers, Rachel A. Whitmer, PhD, of Kaiser Permanente in Oakland, Calif., and colleagues reported.
The brain might not see the most immediate impact of smoking -- but isn't immune to its long-term effects, Whitmer and co-authors cautioned online in the Archives of Internal Medicine.
Smokers are more likely to die of other causes but shouldn't think they've gotten off scot-free if they don't have a heart attack or get lung cancer or emphysema, Whitmer noted in an interview monitored by a Kaiser Permanente media relations employee.
"If they've made it to late life and don't have respiratory disease or vascular disease, they need to know that their brain is also at risk," Whitmer told MedPage Today. "They need to know that there are long-term consequences."
The negative public health impact of smoking has the potential to become even greater as the population worldwide ages and dementia prevalence increases, she and her colleagues warned in their paper.
Tobacco's link with neurodegenerative or cognitive damage has been somewhat controversial, with some studies even suggesting a lower risk for smokers, Whitmer's group noted.