2003-2013: A Decade of Body Mass Index, Alzheimer's Disease, and Dementia
The year 2013 marked a decade of observational population reports on the association between body mass index (BMI), a common measure of overweight and obesity, and late-onset dementias. In this review, we highlight all epidemiological studies published between 2003 and 2013. These studies measured BMI during midlife (to age 60 years) and BMI measured during late life (after age 65 years) in association with dementia. Epidemiological studies represented countries across 3 continents - Europe, USA, and Asia. Studies investigating the association between midlife BMI and risk for dementia demonstrated generally an increased risk among overweight and obese adults. When measured in late-life, elevated BMI has been associated with lower risk. In addition, being underweight and/or having a decrease in BMI in late-life are associated with higher dementia risk compared to BMI in the normal range or stable BMI. These observations provide a strong base for addressing biological mechanisms underlying this complex association.
Studies investigating the association between midlife (to age 60 years) BMI and risk for dementia show generally an increased risk of dementia among overweight and obese adults. In late-life (after age 65 years), elevated BMI has been associated with lower dementia risk. In addition, being underweight and/or having a decrease in BMI in late-life are associated with higher dementia risk compared to BMI in the normal range or stable BMI.