Abstract
There is increasing attention on the associations between body weight and several neurological and psychiatric disorders. Using a total of 438,483 participants from the UK Biobank, we aimed to understand the effects of body mass index (BMI), BMI change and BMI-metabolic health status on the incidence of common neurological and psychiatric disorders. Associations of body weight with six disorders (stroke, dementia, Parkinson’s disease, anxiety, depression and sleep disorders) were analysed by Cox regression models. We performed linear regression models and mediation analysis to explore the underlying mechanisms. Overweight or obesity group had a higher risk of stroke, anxiety, depression and sleep disorders. Metabolically healthy obesity demonstrated a higher risk of depression and sleep disorders. The differing effects of metabolically healthy versus unhealthy obesity on brain structure, dietary intake and inflammatory markers provided clues to the underlying associations. Hence, weight management should be recommended for individuals with obesity irrespective of their metabolic health status.