Low 25-hydroxyvitamin D levels are associated with decreased vital capacity of lung

Abstract

Background : Many studies suggest a role for vitamin D in respiratory diseases, but the effect of vitamin D on pulmonary function has not been studied extensively.Objective : We investigated whether serum vitamin D concentration might be associated with lung function.Methods : This study was based on the data acquired in the second year (2008) of the fourth National Health and Nutrition Examination Survey, a cross-sectional survey that was conducted from 2007 to 2009. The analysis included 2205 subjects who were older than 40 years and had complete data from both pulmonary function tests and serum 25-hydroxyvitamin D (25(OH)D) concentrations. Participants were divided into quartile categories of serum 25(OH)D concentration.Results : Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were positively associated with increasing serum concentrations of 25(OH)D after adjustment with age, gender, smoking status, cigarette pack-years smoked, height, body weight, daily energy intake, intake of vitamin supplements, regions, occupations and physical activity. However, the FEV1/FVC ratio was not significantly associated with serum 25(OH)D levels.Conclusions : The results suggest that low vitamin D level are associated with deficits in lung function by not airway obstruction but decreased vital capacity.