Association between serum 25-hydroxyvitamin D levels and pulmonary function, among Korean adults, during 2010-2014, by sex, age, and body mass index

Abstract

BACKGROUND: This study examined the association between serum 25-hydroxyvitamin D (25(OH)D) and pulmonary function, among Korean adults, from 2010 to 2014. METHODS: The data were obtained from the fifth Korea National Health and Nutrition Examination Survey (KNHANES 5), and the first and second year (2013-2014) of KNHANES 6. The study population comprised 14,378 individuals. The variable of interest was serum 25(OH)D, and the dependent variable, pulmonary function. RESULTS: All people with vitamin D levels below 30ng/ml had lower lung functions, which was significant in lower forced expiratory volume in the first second (FEV1) (serum 25(OH)D<10ng/ml, 20 to <30ng/ml: P=.001, 10 to <20ng/ml: P=0) and forced vital capacity (FVC) (serum 25(OH)D level <10ng/ml: P=.01, 10 to<20ng/ml: P=.001, 20 to <30ng/ml: P=.008). The lower the serum 25(OH)D, the lower the levels of FEV1 in men and this was significant. (serum 25(OH)D<10ng/ml: P=.007, 10 to <20ng/ml: P=.002, 20 to <30ng/ml: P=.007). The values of FEV1 and FVC were lower in people aged 50-69 years when vitamin D was lower than 30ng/ml which were all significant. Among participants with BMI values<23kg/m(2), lower vitamin D levels were significantly associated with lower pulmonary function. CONCLUSIONS: We found a significant association between serum 25(OH)D and pulmonary function, and this was related to sex, age and body mass index.