Variability in body weight precedes diagnosis in dementia: A nationwide cohort study.

BACKGROUND: While there have been disagreements concerning whether obesity and increase in body weight elevate the risk of dementia, variability in body weight has been recently recognized as a new biometric associated with a high risk for a number of diseases. This nationwide, population-based cohort study examined the association between body weight variability and dementia. METHODS: A total of 2,812,245 adults (mean age, 51.7 years; standard deviation, 8.6) without a history of dementia who underwent at least three health examinations between 2005 and 2012 in a nationwide cohort were followed-up until the date of dementia diagnosis (based on prescribed drugs and disease code) or until 2016 (median follow-up duration, 5.38 years; interquartile range, 5.16-5.61). Cox regression models were used to evaluate the risk of Alzheimer's disease and vascular dementia according to body weight variability. RESULTS: The hazard ratios (95% confidence intervals) of the highest quartiles of variability were 1.42 (1.35-1.49) for Alzheimer's disease and 1.47 (1.32-1.63) for vascular dementia compared to the lowest quartile group as a reference. This association was consistent in various subgroup analyses and sensitivity analyses. CONCLUSIONS: Body weight variability could predict Alzheimer's disease and vascular dementia, which may provide new insights into the prevention and management of dementia.