title: Cigarette smoking and dementia: potential selection bias in the elderly.
abstract: We conducted a systematic review of published prospective studies that estimated the association between smoking and the incidence of Alzheimer disease and dementia. The relative rate for smokers versus nonsmokers ranged from 0.27 to 2.72 for Alzheimer disease (12 studies) and from 0.38 to 1.42 for dementia (6 studies). The minimum age at entry (range: 55-75 years) explained much of the between-study heterogeneity in relative rates. We conjecture that selection bias due to censoring by death may be the main explanation for the reversal of the relative rate with increasing age.
authors.affiliation: Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA. miguel_hernan@post.harvard.edu
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Hernán
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alonso
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Logroscino
mesh_terms: D000368:Aged; D003704:Dementia / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D015983:Selection Bias; D012907:Smoking / Q000009:adverse effects*