Metabolically healthy obesity increases the prevalence of stroke in adults aged 40 years or older: Result from the China National Stroke Screening survey

Debate over the cardio-cerebrovascular risk associated with metabolically healthy obesity (MHO) continues. In this study we investigated the association of MHO with the risk of stroke among 221,114 individuals aged 40 years or older based on data from the China National Stroke Screening and Prevention Project (CNSSPP), a nationally representative cross-sectional study, during 2014 to 2015. Different metabolic health and obesity phenotypes were defined according to the Adult Treatment Panel III (ATP III) criteria, where obesity was defined as a body mass index (BMI) ≥28 kg/m2. Logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for stroke risk associated with different metabolically healthy phenotypes. BMI was used to estimate the mediation effect for metabolic abnormalities to stroke. Compared with the metabolically healthy non-obesity (MHNO) group, individuals with MHO (adjusted OR: 1.21, 95% CI: 1.10,1.33), metabolically unhealthy non-obesity (MUNO) (adjusted OR:1.41, 95% CI: 1.36,1.46), or metabolically unhealthy obesity (MUO) (adjusted OR: 1.70, 95% CI: 1.61,1.80) were found to have an increased risk of stroke. The findings were confirmed robustly by various sensitivity analyses and subgroup analyses. Furthermore, obesity and metabolic abnormalities had an additive interaction for stroke risk with an attributable proportion (AP) of 14.0% in females. BMI played a partial mediating role with the proportion of the effect (PE) at 11.1% in the relationship between metabolic abnormalities and stroke. This study strengthens the evidence that management and interventions in the MHO population may contribute to the primary prevention of stroke.