Lung function and metabolic syndrome: Findings of National Health and Nutrition Examination Survey 2007-2010

Background: Considerable uncertainty remains about obstructive lung function (OLF) in adults with metabolic syndrome (MetS). The aim of the present study was to examine pulmonary function status in adults with and without MetS. Methods: We used data from 3109 participants aged >= 20 years of the National Health and Nutrition Examination Survey 2007-2010. Subjects' MetS status was established on the basis of the 2009 harmonizing definition. Participants received spirometry. Results: After age adjustment, 79.3% (SE 1.1) of participants with MetS had normal lung function, 8.7% (0.9) had restrictive lung function (RLF), 7.1% (0.8) had mild OLF, and 4.8% (0.6) had moderate OLF or worse. Among participants without MetS, these estimates were 78.7% (1.2), 3.9% (0.6), 10.9% (1.1), and 6.4% (0.8), respectively. After multiple adjustment, participants with MetS were more likely to have RLF (adjusted prevalence ratio [ aPR] 2.20; 95% confidence interval [ CI] 1.67, 2.90) and less likely to have any OLF (aPR 0.73; 95% CI 0.62, 0.86) than those without MetS. Furthermore, participants with MetS had lower mean levels of forced expiratory volume in one second (FEV1), FEV1 % predicted, forced vital capacity (FVC), and FVC % predicted, but a higher FEV1/FVC ratio than participants without MetS. Mean levels of FEV1, FEV1 % predicted, FVC, and FVC % predicted declined significantly, but not the FEV1 /FVC ratio, as the number of components increased. Conclusions: Compared with adults without MetS, spirometry is more likely to show a restrictive pattern and less likely to show an obstructive pattern among adults with MetS.