Long-Term Weight History Reveals Substantial Dementia Burden Attributable to Obesity

Background: The association between obesity and dementia has historically been inconsistent, partly because studies often rely on body mass index (BMI) measured late in life, when preclinical neurodegenerative disease may cause weight loss and obscure causal relationships. Objective: To assess the risk of dementia associated with obesity by examining maximum BMI over 10 years of weight history using data from the U.S. Health and Retirement Study. Design: Cohort study. Participants: The cohort included 3734 adults aged 50 to 79 years followed for up to 16 years, during which 395 incident dementia cases occurred. Methods: Participants were categorized by their highest BMI during the weight-history window rather than by baseline BMI alone. Multivariable Cox regression models were used to estimate dementia risk while adjusting for demographic and lifestyle factors. Results: Compared with individuals whose maximum BMI remained in the normal range (18.5 to 24.9 kg/m 2 ), dementia risk incr more...