Body Mass Index (BMI) categories alone do not necessarily predict negative outcomes. We examined if further stratification based on metabolic syndrome (MetS) provides additional value in predicting mortality. We analyzed population-based data from adults in the National Health and Nutrition Examination Survey from 1999-2010. BMI categories (in kg/m2) were: normal (18.5-25), overweight (25-30) and obese (>30). Normal BMI participants without MetS served as the reference group. After initial unadjusted analyses we performed Cox proportional hazards models controlling for age, gender, race-ethnicity, education, income and smoking. We included 12,048 participants. Unadjusted mortality curves (Figure) show that the normal MetS group had the highest mortality rate, followed by overweight MetS, which in turn is significantly higher than obese MetS. All the no MetS groups had significantly lower mortality than their MetS counterparts. Adjusted Cox regression showed that only the normal MetS (HR 1.7, CI 1.2-2.4) and obese MetS group (HR 1.3, CI 1.1-1.6) had higher hazard rates than the reference group. Metabolic syndrome and obesity categories provide significant additional prediction of mortality. Normal weight subjects with MetS have the highest mortality, in contrast to previous studies. Treatment strategies should incorporate MetS and obesity.
T. Shi: None. S. Natarajan: None.