Does Higher Body Mass Index Lower Cognitive Functioning at Old-Age?

Bo Macinnis, University of Michigan

Cognitive performance declines with age, and impaired cognition is a major health problem with substantial economic costs. Old-age obesity is prevalent and increasing. While the physical health effects of obesity have been well-documented and consistently found to be adverse, the consequences of obesity on cognitive health at old-age are less well understood with widely varied results and conflicting evidence. Some studies show obesity is harmful to cognition; some report obesity is protective, while others find no relationship. The inconclusiveness of the literature may result from differences in study samples, measures of cognitive domains, and methodology. We contribute to the literature by using the Health and Retirement Study and measures of multiple cognitive domains, and importantly, an econometric analysis that models unobserved individual permanent heterogeneity, and the potential endogeneity of obesity. We demonstrate the importance of these econometric issues and how the difference in estimation methods yields different (opposite direction) results.