Association Between Weight Status and Rate of Cognitive Decline: China Health and Nutrition Survey 1997-2018

Background There is a close relationship between weight status and cognitive impairment in older adults. This study examined the association between weight status and the trajectory of cognitive decline over time in a population-based cohort of older adults in China. Methods We used data from adults aged >= 55 years participating in the China health and nutrition survey (1997-2018). Underweight (body mass index [BMI] <= 18.5 kg/m(2)), normal weight (18.5-23 kg/m(2)), overweight (23-27.5 kg/m(2)), and obesity (BMI >= 27.5 kg/m(2)) were defined using the World Health Organization Asian cutpoints. Global cognition was estimated every 2-4 years through a face-to-face interview using a modified telephone interview for cognitive status (scores 0-27). The association between BMI and the rate of global cognitive decline, using a restricted cubic spline for age and age category, was examined with linear mixed-effects models accounting for correlation within communities and individuals. Results We included 5 992 adults (53% female participants, mean age of 62 at baseline). We found differences in the adjusted rate of global cognitive decline by weight status (p = .01 in the cubic spline model). Models were adjusted for sex, marital status, current employment status, income, region, urbanization, education status, birth cohort, leisure activity, smoking status, and self-reported diagnosis of hypertension, diabetes, or Myocardial Infarction (MI)/stroke. In addition, significant declines by age in global cognitive function were found for all weight status categories except individuals with obesity. Conclusions In a cohort of adults in China, cognitive decline trajectory differed by weight status. A slower rate of change was observed in participants classified as having obesity.

Automated summary

This study examined the association between weight status and trajectory of cognitive decline in older adults in China. The results showed that weight status was related to the rate of global cognitive decline, with slower decline observed in individuals classified as having obesity.