Accelerated Weight Loss and Incident Dementia in an Elderly African-American Cohort

Obesity is associated with risk of diabetes mellitus, hypertension, and cardiovascular disease, conditions related to risk of dementia. There are studies confirming that midlife obesity is a risk factor for dementia,1,2 but studies on the relationship between body mass index (BMI) measured later in life and dementia have yielded inconsistent results, with some finding participants with higher BMI measures at greater risk3 and some at lower risk,4–6 and some finding no significant association with dementia.7 There are also reports that low BMI is associated with greater risk of dementia.5 A further complication to the relationship between BMI and dementia is that several studies have shown that weight loss may precede dementia diagnosis, suggesting that the timing of BMI measures from the time of dementia onset may determine the relationship between BMI and dementia risk. Existing studies on BMI and dementia risk have not included substantial numbers of African-American participants, a group with the highest obesity rate of all ethnic groups in the United States.8 It is therefore important to assess whether changes in BMI are associated with risk of dementia in this particular population as has previously been shown in predominately white populations. Data from the Indianapolis cohort of the Indianapolis-Ibadan Dementia Project, including elderly community-dwelling African-American participants living in Indianapolis, were used. Participants completed repeated evaluations including height and weight measures, cognitive assessment, and clinical evaluation for the diagnosis of dementia or mild cognitive impairment (MCI). Analysis results on the association between repeated BMI measures and incident dementia and MCI diagnosis are reported.