The Relationship between Lung Function and Metabolic Syndrome in Obese and Non-Obese Korean Adult Males

BACKGROUND The existence of an association between lung function and metabolic syndrome (MetS) has been debated in cases involving non-obese subjects. To address this debate, we performed a cross-sectional study to investigate the association between lung function and MetS in both obese and non-obese populations. METHODS The present study consisted of a total of 1,951 Korean male subjects. In this study group, we investigated relationships between lung function and MetS risk factors such as fasting serum glucose, systolic blood pressure (SBP), insulin resistance index, waist circumference (WC), and hemoglobin A(1C) level. RESULTS Forced vital capacity (FVC) values were significantly lower in the MetS group compared with those of the non-MetS group. In both non-obese (body mass index [BMI] < 25 kg/m(2)) and obese subjects (BMI ≥ 25 kg/m(2)), fasting serum glucose, hemoglobin A(1C) level, insulin resistance index, SBP, WC, and the prevalences of diabetes and MetS were significantly higher in subjects in the lowest FVC quartile compared with those in the highest FVC quartile. Odds ratios for the presence of MetS risk factors, after adjusting for age and height, ranged from 1.21 to 1.39 (P < 0.01) for a one standard deviation decrease in FVC. CONCLUSION The results of our study suggest that decreased vital capacity in Korean adult male subjects is associated with MetS, irrespective of obesity.