Abstract
BACKGROUND: Prospective longitudinal studies have shown inconsistent effects of obesity phenotypes on the risk of cardiovascular disease (CVD) mortality. Also, longitudinal evidence from Chinese populations remained scarce. We aimed to investigate the association of obesity phenotypes assessed by body mass index (BMI) and metabolic syndrome (MetS) with risk of CVD mortality, leveraging the unique adiposity patterns and metabolic vulnerability of Asian populations. METHODS: A subset of 26,884 participants (aged 49.30 ± 10.37 years, 39.23% men) from Taizhou longitudinal study were followed up to 8 years. Obesity phenotypes were categorized into 4 groups including metabolically healthy non-obese (MHNO), metabolically healthy obese (MHO), metabolically unhealthy non-obese (MUNO) and metabolically unhealthy obese (MUO), using BMI categories from Chinese criteria (obesity: ≥28.0 kg/m²) and MetS defined by International Diabetes Federation (IDF) consensus. The death caused by CVD were identified based on international classification of diseases-10th Revision (ICD-10). Data were analyzed using the Cox regression models and Laplace regression models. RESULTS: Of 26,884 participants, 15,462 (57.5%), 1,702 (6.3%), 3,656 (13.6%) and 2,064 (7.7%) subjects were classified into the MHNO, MHO, MUNO and MUO group, respectively. At the end of the follow-up, 113 (0.39%) participants died because of CVD. Compared with the MHNO group, the hazards ratios (HRs) and 95% confidence intervals (CIs) of CVD mortality were 1.73 (1.03–2.91) and 1.97 (1.11–3.52) respectively in MUNO and MUO group. The multi-adjusted 50th percentile differences (50th PDs) (95% CIs) of time at incident CVD mortality in MUNO and MUO group were 0.97 (0.00-1.93) and 1.35 (0.31–2.39) years earlier respectively than those in MHNO group. MHO group showed no significant risk elevation (HR = 1.21, 0.68–2.17) despite the earlier 50th percentile differences of CVD mortality years (50th PD = 0.94, 95%CI: 0.38–2.25). CONCLUSIONS: Metabolic abnormalities increased the risk of CVD mortality especially in participants with obesity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-025-23628-w.