Neurology
Association of obesity with dementia over 24 years of weight history in the Framingham Heart Study Phillip Hwang* Phillip Hwang Rafeya Raquib Hanfei Xu Rhoda Au M. Maria Glymour Andrew Stokes
Background: Many studies of the association between obesity and dementia rely on weight status at a single point in time, making it difficult to adequately address bias associated with reverse causality. The objective of this analysis was to examine the association between maximum body mass index (BMI) and all-cause dementia without the consequences of reverse causality.
Methods: Longitudinal cohort study from the Framingham Heart Study. The follow-up period started from baseline Exam 13 (1972-1976) for the Original cohort and from baseline Exam 5 (1991-1995) for the Offspring cohort, and ended December 31, 2021. Maximum BMI (kilograms/meters2) over 24 years of objectively measured weight history before the beginning of follow-up for dementia. All-cause dementia was based on expert consensus using standard diagnostic criteria. Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between maximum BMI and dementia, with individuals in the normal BMI range (BMI 18.5-24) as the reference group, and adjusting for baseline age, sex, cohort, smoking, alcohol intake, education, and duration between exam of reaching maximum BMI and baseline exam.
Results: Among 6067 participants (mean [SD] age at baseline=62.4 [8.8] years; 55.5% female), 1303 (21.5%) developed dementia during the follow-up. A monotonic association was observed between maximum BMI and dementia, with obese II (BMI 35-39) significantly associated with increased risk of dementia (HR=1.35; 95% CI=1.07-1.71). A significant association was not observed for the overweight (BMI 25-29; HR=1.05; 95% CI=0.91-1.21) or obese I (BMI 30-34; HR=1.16; 95% CI=0.98-1.37) categories.
Conclusions: A monotonic association was found between maximum BMI over 24 years of weight history and subsequent all-cause dementia. Maximum BMI in the normal weight range was associated with the lowest risk of dementia in the sample, highlighting the importance of obesity prevention.