Association of changes in predicted body composition with subsequent risk of dementia

Abstract

Objective: The effect of body composition change on the risk of dementia is not clear. This study analyzed the associations of changes in predicted lean body mass index (pLBMI), predicted appendicular skeletal muscle mass index (pASMI), and predicted body fat mass index (pBFMI) with the risk of dementia. Methods: In this nationwide cohort study, data were obtained from the Korean National Health Insurance Service database. The exposure was defined as changes in pLBMI, pASMI, and pBFMI derived from validated prediction equations. The outcome was dementia, defined based on the dementia diagnosis with prescription of anti-dementia medication. Cox proportional hazards regression analyses were performed to obtain the hazard ratio with a 95% confidence interval for risk of dementia according to changes in predicted body composition. Results: A total of 13,215,208 individuals with no prior record of dementia who underwent health screenings twice between 2009–2010 and 2011–2012 were included. A 1-kg/m2 increase in pLBMI and pASMI had an association with reduced risk of dementia (aHR: 0.85, 95% CI 0.84–0.87; aHR: 0.70, 95% CI 0.69–0.72, respectively for men, and aHR: 0.69, 95% CI 0.67–0.71; aHR: 0.59, 95% CI 0.57–0.61, respectively for women). A 1-kg/m2 increase in pBFMI had an association with a raised risk of dementia (aHR: 1.19, 95% CI 1.17–1.21 for men and aHR: 1.53, 95% CI 1.48–1.57 for women). These results remained consistent regardless of sex or weight change. Interpretation: Increase in pLBMI or pASMI, or reduction in pBFMI was linked to lower risk of dementia.