Nonagenarian Women More Likely to Be Demented Than Men

Women who live into their 90s are significantly more likely to be demented than similarly aged men, according to a report in this week's issue of Neurology. The finding supports data from previous studies, in which the prevalence of dementia among centenarians was higher among surviving women.

By using in-person examination data and telephone and informant questionnaires, US investigators assessed the all-cause dementia rate among participants in the so-called 90+ Study (N = 911). Among women, the overall dementia rate was 45% (95% CI: 41.5, 49.0), versus 28% (95% CI: 21.7, 34.2) among men. Moreover, the dementia rate in women doubled every 5 years after the age of 90 (Figure). Dementia in women, but not men, correlated inversely with education. From a glass-half-full perspective, dementia was not universal in women 100 years of age or older (61%).

In an accompanying editorial, David Hogan, MD, cites limitations of the study including differing methods used for the diagnosis of dementia; the characteristics of the study population (white, relatively well educated, upper middle class); insufficient pathologic data; a high lost-to-study rate (21%); and a low absolute number of dementia cases among men 95 years of age or older (n = 23). However, Hogan supports the overall conclusion and suggests that the lack of an age-associated increase in dementia among very old men may be due to their shortened survival with the condition.