Variability in body weight and body composition and cognitive trajectories in older adults in the United States.

Abstract

This study examined the associations of variability and patterns in BMI, body weight (BW), and waist circumference (WC) with cognitive decline. A total of 4304 participants (aged ≥65 years) from the National Health and Aging Trends Study between 2011 around 2021 were analyzed. Adjusted mixed-effect models assessed BW and body composition variability metrics linked to cognitive function z scores over 11 years, including standard deviation (SD), coefficient of variation (CV), root mean square error, last-to-first assessment change groups, and overall pattern over the follow-up. Participants in the highest SD variability quartile had the fastest cognitive decline (β = -0.036 [95% CI: -0.044 to -0.028] z scores per year) compared with the lowest variability BMI quartile (β = -0.019 [95% CI: -0.027 to -0.010] z scores per year, p values for interaction, < 0.001). Similar trends were observed for BMI CV and root mean square error, BW SD and CV, and WC CV. Compared with the stable or gain group, participants with ≥5% loss in BMI and BW had the fastest cognitive decline (both p values for interaction, < 0.0002). The cognitive decline rates among the stable, loss, gain and cycling patterns in BMI, BW, or WC were not significantly different. Greater variability and loss in BW and body composition were linked to accelerated cognitive decline in older adults.