Objectives
Impaired lung function(ILF) and sasang constitution(SC) is associated with metabolic syndrome(MS). However, the relationship between ILF and SC is unclear. So, we assessed the relationship between ILF and MS according to SC, and examined whether SC is an independent risk factor for ILF.

Methods
This study included 1,148 subjects 40years and older who were performed the health examination at Kyung Hee University Hospital in Korea between December 2011 and February 2013. We defined ILF if FVC or FEV1 value were less than lower limit of normal(LLN), and classified ventilatory patterns as obstructive pattern and restrictive pattern. MS was assessed according to AHA/NHLBI criteria. We used multivariate logistic regression to analyze the association of ILF with MS respective to SC types, and to identify the risk of SC types for ILF. Odds ratio(OR) was calculated by adjusting for age, sex, smoking status, drinking, physical activity, and BMI.

Results
In whole subjects, ILF was associated with MS [OR (95%CI), 1.69 (1.24-2.31) for FVC, 1.70 (1.22-2.36) for FEV1]. And in Taeeum type(TE type) and Soeum type(SE type), ILF was associated with MS [1.65 (1.11-2.43) for FVC, 1.53 (1.01-2.31) for FEV1 in TE type; 7.01 (1.16-42.34) for FVC in SE type], while in Soyang type(SY type), it wasn’t. The restrictive pattern was associated with MS in TE type and SE type, while in SY type, it wasn’t. Furthermore, TE type and SY type had more risk for ILF than SE type [1.75 (1.15-2.65) for SY type, 1.99 (1.26-3.14) for TE type in FVC; 2.09 (1.28-3.40) for TE type in FEV1; 1.90 (1.24-2.91) for SY type, 2.22 (1.38-3.56) for TE type in Restrictive pattern].

Conclusions
These results show that SC is an independent risk factor for ILF, especially TE type and SY type than SE type, and the prevalence of MS is an independent risk factor for ILF in TE type.

Key words
Sasang Constitution, Metabolic Syndrome, Impaired Lung Function, Risk Factor