Long-term weight change and its temporal relation to later-life dementia in the Health and Retirement Study.

BACKGROUND: Weight loss among middle and older adults has been associated with a higher risk of subsequent dementia. However, most of studies have limited follow-up time or suboptimal control for the potential influence of physical frailty (PF).

OBJECTIVES: Our study aimed to investigate the long-term and temporal relation of weight change to risk of dementia among U.S. middle-aged and older adults.

METHODS: A total of 5985 participants aged 50 years and older were included from the Health and Retirement Study (HRS). History of long-term weight change was calculated using nine repeated BMI measurements from 1992-2008. We then followed their dementia status from 2008 to 2018. Multivariable cox proportional hazard models were used.

RESULTS: During the study follow-up (mean = 7.54 years), a total of 682 (11.39%) dementia cases were documented. After controlling for basic demographic and lifestyle, participants with weight loss (median: -0.23 kg/m 2 per year) were at a significantly higher risk of dementia (HR = 1.60, 95% CI, 1.33, 1.92), compared with the stable-weight group (median: 0.11 kg/m 2 per year). This association was attenuated but remained strong and significant after further adjustment for PF (HR = 1.57, 95% CI, 1.30, 1.89). The significant association was observed for weight loss assessed approximately 14-18 years preceding dementia diagnosis (HR = 1.30, 95% CI, 1.07, 1.58), and was consistent for that closer to diagnosis.

CONCLUSIONS: Both recent and remote weight loss were associated with a higher risk of later-life dementia among middle-aged and older adults independent of the status of physical frailty.