The relationship between changes in body weight and cognitive function in the elderly

Cognitive function is a major concern in aging society. Current studies on the impact of body weight changes on cognitive abilities present conflicting results. This study explored the relationship between weight changes during adulthood and cognitive function in later life. Data were obtained from the National Health and Nutrition Examination Survey (NHANES) and a total of 5097 participants aged 60 years or older with recalled weight at young and middle adulthood were included. Absolute weight change was categorized into five groups: weight loss of at least 2.5 kg, weight change within 2.5 kg (reference group), weight gain of at least 2.5 kg but less than 10.0 kg, weight gain of at least 10 kg but less than 20.0 kg, and weight gain of at least 20.0 kg. Cognitive function was assessed using the Digit Symbol Substitution Test (DSST). Logistic regression models adjusted for covariates were used to compute the odds ratios (ORs) and 95% confidence intervals (CIs) for the association between weight changes and cognitive function. From age 25 to 10 years before survey, participants with small to moderate weight gain (increase of ≥2.5 kg and ≤15.0 kg) showed a significant decline in cognitive function compared to those who maintained stable weight or experienced weight loss. Conversely, participants with large weight gain (>20.0 kg) did not show a significant association with cognitive decline. These findings suggest that weight changes during adulthood may have a more pronounced impact on cognitive function in later life, particularly for individuals with small to moderate weight gain. The results of this study highlight the importance of considering body weight as a potential risk factor for cognitive decline in older adults.