Sex differences in the relationship between metabolic syndrome and pulmonary function: the 2007 Korean National Health and Nutrition Examination Survey.

Pulmonary function impairment has a connection with abdominal obesity, type 2 diabetes, and insulin resistance. Sex differences in lifestyle factors, and pulmonary structure and function may affect pulmonary function in different manners. This study focused on sex differences in the relationship of MetS and its component with pulmonary function. Among 2,614 Korean adults (1,059 men; 1,555 women), pulmonary function was measured by the percentage of predicted forced vital capacity (FVC (%)) and a ratio between forced expiratory volume in 1 second (FEV(1))/FVC. FVC (%) and FEV(1)/FVC were compared according to the presence of MetS and its components. Multiple linear regression analysis was conducted to assess the association between FVC (%), FEV(1)/FVC and clinical variables. We found sex differences in the relationship of MetS and its components with pulmonary function. FVC (%) was significantly lower in subjects with MetS than in those without MetS in both men and women, and FEV(1)/FVC was lower in subjects with MetS only in women. Among components of MetS, waist circumference, blood pressure and fasting plasma glucose, and HDL-cholesterol were independently related to FVC (%) in men, whereas waist circumference was significantly associated with FVC (%) in women. Blood pressure was found to be an independent factor of FEV(1)/FVC in men, whereas blood pressure, fasting plasma glucose and HDL-cholesterol independently determined FEV(1)/FVC in women. These findings suggest that sex-specific association between MetS and lung function measures should be considered in clinical practice.