The role that vitamin D plays in pulmonary function remains uncertain. Epidemiological studies reported mixed findings for serum 25-hydroxyvitamin D (25(OH)D)-pulmonary function association. We conducted the largest cross-sectional meta-analysis of the 25(OH)D-pulmonary function association to date, based on nine European ancestry (EA) cohorts (n 22 838) and five African ancestry (AA) cohorts (n 4290) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Data were analysed using linear models by cohort and ancestry. Effect modification by smoking status (current/former/never) was tested. Results were combined using fixed-effects meta-analysis. Mean serum 25(OH)D was 68 (sd 29) nmol/l for EA and 49 (sd 21) nmol/l for AA. For each 1 nmol/l higher 25(OH)D, forced expiratory volume in the 1st second (FEV1) was higher by 1·1 ml in EA (95 % CI 0·9, 1·3; P<0·0001) and 1·8 ml (95 % CI 1·1, 2·5; P<0·0001) in AA (P race difference=0·06), and forced vital capacity (FVC) was higher by 1·3 ml in EA (95 % CI 1·0, 1·6; P<0·0001) and 1·5 ml (95 % CI 0·8, 2·3; P=0·0001) in AA (P race difference=0·56). Among EA, the 25(OH)D-FVC association was stronger in smokers: per 1 nmol/l higher 25(OH)D, FVC was higher by 1·7 ml (95 % CI 1·1, 2·3) for current smokers and 1·7 ml (95 % CI 1·2, 2·1) for former smokers, compared with 0·8 ml (95 % CI 0·4, 1·2) for never smokers. In summary, the 25(OH)D associations with FEV1 and FVC were positive in both ancestries. In EA, a stronger association was observed for smokers compared with never smokers, which supports the importance of vitamin D in vulnerable populations.
Keywords: 1; 25(OH)D 25-hydroxyvitamin D; AA African ancestry; AGES Age; ARIC Atherosclerosis Risk in Communities Study; Aging; CARDIA Coronary Artery Risk Development in Young Adults Study; CHARGE Cohorts for Heart and Aging Research in Genomic Epidemiology; CHS Cardiovascular Health Study; COPD chronic obstructive pulmonary disease; EA European ancestry; Environment; FEV1 forced expiratory volume in the 1st second; FHS (Gen3) Framingham Heart Study – Generation 3 Cohort; FHS (Offspring) Framingham Heart Study –Offspring Cohort; FVC forced vital capacity; Gene; HABC Health; Iceland; MESA Multi-Ethnic Study of Atherosclerosis; PFT pulmonary function test; RIA radioimmunoassay; Susceptibility Study − Reykjavik; and Body Composition Study; 25-(OH)2D 1; 25-dihydroxyvitamin D; African Americans; Forced expiratory volume; Respiratory function tests; Smoking; Vital capacity; Vitamin D; Whites.