Prevalence and determinants of metabolically healthy obesity in Spain

Background and aims: Obesity is a heterogeneous disorder, so some obese individuals do not have cardiometabolic abnormalities (CA) which mediate the association between obesity and coronary heart disease. This study assessed the prevalence of metabolically healthy obesity and its determinants in Spain. Methods: The data were taken from a cross-sectional study conducted in 2008-2010 among 11,520 individuals representative of the population of Spain aged ≥18 years. Normal-weight was defined as body mass index (BMI) <25kg/m2, and obesity as BMI ≥30kg/m2. Six CA were considered: elevated blood pressure, low high-density lipoprotein cholesterol, and elevated levels of triglycerides, fasting glucose, homeostasis model assessment of insulin resistance value, and C-reactive protein. Then, two phenotypes were defined: healthy (0-1 CA) and abnormal (≥2 CA). Results: The prevalence of metabolically healthy obesity was 6.5% overall (95% confidence interval:6.0-7.1), and corresponds to 28.9% of obese individuals. Lower age, being female, current smoking, moderate alcohol consumption, and high level of physical activity were independently associated with the healthy phenotype among the obese. The prevalence of normal weight with a metabolically abnormal phenotype was 6.4% overall (95% confidence interval: 5.8-6.9) and corresponds to 16.8% of normal-weight subjects. Factors associated with this phenotype in normal-weight persons were higher age, being male, never smoking, no alcohol consumption and larger waist circumference. Conclusion: Metabolically healthy obesity represents almost one-third of the obese population in Spain. Since this was a cross-sectional study, the association of metabolic healthy obesity with smoking consumption, alcohol intake and physical activity warrants more research.