Plain language summary
Lower socioeconomic status is associated with worse health outcomes, and in particular with cardiovascular disease and metabolic syndrome. This association is thought to be mediated through lifestyle factors such as physical activity, diet and smoking. Level of education is commonly used as an indicator for socioeconomic status. This Korean cross-sectional study, involving 988 healthy adults, evaluated the association between level of education (<12 years, 12-16 years, >16 years), cardiorespiratory fitness (CRF) and metabolic syndrome. People in the highest education group were more likely to be younger and male. There was no difference in the prevalence of metabolic syndrome, hypertension or diabetes mellitus between the three educational attainment groups, 36.1% overall had metabolic syndrome. There was also no difference in dyslipidaemia, physical activity or smoking status. Whilst BMI was similar in all groups, the higher the level of education, the lower the body fat and the higher lean mass and CRF were. Although education was not associated with metabolic syndrome, better CRF was associated with lower rates of metabolic syndrome. Limitations of the study as pointed out by the authors include the retrospective design and a potentially non-representative sample.
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.