Is the risk of developing Alzheimer's disease greater for women than for men?

A large proportion of people with Alzheimer's disease (AD) are women; howev er, it is not clear whether this is due to higher risk of disease or solely to the larger number of women alive at ages when AD is common. Beginning i n 1982, two stratified random samples of people aged greater than or equal to 65 years in East Boston, Massachusetts underwent detailed, structured cl inical evaluation for prevalent (467 people) and incident (642 people from a cohort previously ascertained to be disease-free) probable AD. The preval ence sample was followed for mortality for up to 11 years (through December 1992). The age-specific incidence of AD did not differ significantly by se x (for men vs, women, odds ratio = 0.92; 95% confidence interval (CI): 0.51 , 1.67). Controlled for age, prevalence also did not differ significantly b y sex (for men vs, women, odds ratio = 1.29; 95% CI: 0.67, 2.48). The incre ase in risk of mortality due to AD did not vary by sex. The odds ratio for women with AD compared with women without AD was 2.07 (95% CI: 1.21, 3.56). For men, the odds ratio was 2.22 (95% CI: 1.02, 4.81). These findings sugg est that the excess number of women with AD is due to the longer life expec tancy of women rather than sex-specific risk factors for the disease.