Weight loss and risk of dementia in individuals with versus without obesity

Abstract

INTRODUCTION: Using nationwide cohort data, we aimed to elucidate whether baseline obesity altered the relationship between loss in body mass index (BMI) or waist circumference (WC) and risk of dementia. METHODS: Among 9689 participants whose BMIs and WCs were repeatedly measured over 1 year, 1:1 propensity score matching was conducted between participants with and without obesity (n = 2976 per group, mean age 70.9). For each group, we explored the association between loss in BMI, or WC, and incidence of dementia during an approximately 4-year follow-up period. RESULTS: BMI loss was associated with an increased risk of all-cause dementia and Alzheimer's disease in participants without obesity; however, this association was absent in participants with obesity. WC loss was associated with decreased Alzheimer's disease risk only in participants with obesity. DISCUSSION: Only unfavorable loss (loss from non-obese state) in BMI, not WC, can be a metabolic biomarker of prodromal dementia.