All Cause and Cardiovascular Mortality Risk in Metabolically Healthy and Unhealthy Obesity: Results From NHANES 1999-2018

Background Metabolically healthy obese (MHO) is not static; it can transform into Metabolically Unhealthy Obesity (MUO) over time. Whether MHO individuals at the baseline, who appear to defy the expected health consequences of obesity, indeed experience a lower risk of mortality when compared to their counterparts with MUO. Methods In a cohort study using data from the National Health and Nutrition Examination Survey (NHANES) thorough 1999–2018, metabolic health and obesity status were assessed at baseline. Participants were followed up for 112-months follow-up to ascertain cardiovascular and all-cause mortality events. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) adjusting for potential confounders. Stratified analyses and sensitivity analyses were performed. Results In a cohort of 18,869 participants, with a median 112-month follow-up, 2581 all-cause deaths and 842 cardiovascular deaths were observed. MHO individuals had significantly higher survival rates for both all-cause and cardiovascular mortality compared to MUO participants (p < 0.05). Adjusted multivariable models consistently showed that MHO individuals had lower rates of all-cause mortality (HR 0.85; 95% CI 0.76, 0.95) and cardiovascular mortality (HR 0.85; 95% CI 0.76, 0.94). There were no significant interactions between MHO and these factors except for a slight decrease in the association strength among older participants, drinkers, former smokers, and those with self-reported hypertension. Sensitivity analyses, including the exclusion of shorter follow-up times and baseline cardiovascular disease cases, consistently supported the protective effect of MHO against both all-cause mortality (HR, 0.84 to 0.92) and cardiovascular mortality (HR, 0.86 to 0.92) compared to MUO. Conclusion our extensive analysis of a large cohort spanning nearly a decade highlights that individuals with MHO consistently exhibit significantly lower rates of all-cause and cardiovascular mortality compared to their MUO counterparts. These findings emphasize the critical role of metabolic health in evaluating mortality risk among obese individuals and underscore the potential for more personalized healthcare strategies and public health policies to address obesity-related health outcomes.