Prevalence of metabolically healthy obesity and its impacts on incidences of hypertension, diabetes and the metabolic syndrome in Taiwan

Obesity is an epidemic health problem related to morbidity and mortality of metabolic and cardiovascular diseases. However, little is known regarding the development of cardiometabolic diseases in an obese subgroup with a healthy metabolic risk profile. This study examined the prevalence of baseline metabolically healthy obese subjects and its impacts on the incidences of cardiometabolic diseases using a nation-wide population cohort. Metabolically healthy obese were prevalent in 8.2% of the baseline population and 28.5% of the obese subjects. Subjects included were 1,547 men and women (age range, 18-59 years), who were free of components of the metabolic syndrome except waist criteria. During an average 5.4-year follow-up, the cumulative incidences of hypertension, type 2 diabetes and the metabolic syndrome were 7.8%, 1.2% and 5.6%, respectively. The hazard ratios (95% CIs) for the metabolic syndrome incidence were significantly higher at BMI levels of ≥23.0 kg/m² [4.68 (2.22-9.86)] for BMI of 23-24.9 kg/m²; 8.82 (4.01-19.4) for BMI of 25-26.9 kg/m²; and 24.4 (12.3-48.4) for BMI of ≥27 kg/m²). The hazard ratios for diabetes or hypertension incidence were significantly higher at BMI levels of ≥25.0 kg/m². Each kg/m² of BMI gained was associated with an 18% increase in the risk of developing hypertension and a 26% increase in risk for the metabolic syndrome. We conclude that metabolically healthy obese individuals are at higher risk to develop hypertension, type 2 diabetes and the metabolic syndrome than their nonobese counterparts. Our data provide further evidence that opposes the notion of metabolically healthy obese as harmless conditions.