Associations between metabolic obesity phenotypes and incident cardiovascular disease in middle-aged and elderly Chinese individuals

Although the relationship between cardiovascular disease (CVD) and body weight and metabolic health is well established, limited research has comprehensively examined how combined metabolic status and obesity phenotypes—defined using body mass index (BMI) and waist circumference (WC)—influence CVD risk. This study investigates the associations between metabolic obesity phenotypes and CVD in a middle-aged and older Chinese population. The study utilized longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS). Weighted logistic regression, Poisson regression and restricted cubic spline (RCS) models were conducted to evaluate associations between metabolic obesity phenotypes and CVD. Incident CVD differed significantly across metabolic obesity phenotypes (p<0.001). Using metabolically healthy normal-weight (MHN) individuals as the reference group, all other phenotypes were associated with increased CVD risk following BMI criteria RR (95% CI): metabolically healthy overweight (MHOW): 1.65 (1.04-2.64); metabolically healthy obesity (MHO): 3.89 (2.02-7.50); metabolically unhealthy normal weight (MUN): 1.60 (1.22-2.10); metabolically unhealthy overweight (MUOW): 1.86 (1.41-2.46); metabolically unhealthy obesity (MUO): 2.64 (1.96-3.55). Using WC criteria also revealed elevated risks MHO: 1.84 (1.23-2.77); MUN: 1.58 (1.14-2.20); MUO: 2.22 (1.63-3.04). BMI exhibited a linear relationship with CVD risk in metabolically healthy individuals and a non-linear relationship in those with metabolic abnormalities. Increasing WC was consistently associated with higher CVD risk across all metabolic subgroups. Distinct metabolic obesity phenotypes demonstrate varying degrees of association with CVD. Notably, obesity independently predicted elevated CVD risk across all metabolic categories. These findings emphasize the importance of comprehensive weight management strategies for all individuals, including those currently classified as metabolically healthy, to mitigate potential cardiovascular complications.