The impact of educational attainment on cardiorespiratory fitness and metabolic syndrome in Korean adults

The aim of this study was to evaluate the relationship between educational attainment and cardiorespiratory fitness (CRF) as a predictor of metabolic syndrome in a Korean population.In this single-center, retrospective cross-sectional study, 988 healthy adults (601 men and 387 women) who underwent regular health check-up in Seoul St. Mary's Hospital were analyzed. Educational attainment was categorized into 3 groups according to their final grade of educational course: middle or high school (≤12 years of education), college or university (12-16 years of education), and postgraduate (≥16 years of education). CRF was assessed by cardiopulmonary exercise testing, biceps strength, hand grip strength, bioelectrical impedance analysis, and echocardiography. Metabolic syndrome was diagnosed according to the 3rd report of the National Cholesterol Education Program.Among the subjects, 357 (36.1%) had metabolic syndrome. The postgraduate group had significantly higher peak oxygen consumption (VO2), biceps strength, hand grip strength, and peak expiratory flow than other groups (all P < .001). This group showed better left ventricular diastolic function, in terms of deceleration time of mitral inflow, maximal tricuspid valve regurgitation velocity, and left atrial volume index than other groups. Peak VO2 (%) was significantly correlated with all the parameters of metabolic syndrome, including insulin resistance (r = -0.106, P = .002), waist circumference (r = -0.387, P < .001), triglyceride (r = -0.109, P = .001), high density lipoprotein-cholesterol (r = 0.219, P < .001), systolic blood pressure (r = -0.143, P < .001), and diastolic blood pressure (r = -0.177, P < .001). And Peak VO2 (%) was found to be a predictor of metabolic syndrome (adjusted β = .988, P < .001). However, the level of education was not able to predict metabolic syndrome (postgraduate group; β = .955, P = .801).Although the postgraduate group had better CRF than other groups, the educational attainment could not exclusively predict metabolic syndrome in this study. Further research is needed to reveal the socioeconomic mechanism of developing metabolic syndrome.