Large Meta-Analysis Provides Evidence For An Association Of Serum Vitamin D With Pulmonary Function

Background: Epidemiological studies have reported mixed cross-sectional findings for the association of serum 25-hydroxyvitamin D [25(OH)D] and pulmonary function in the general population. We conducted the largest meta-analysis of the serum 25(OH)D-pulmonary function association to date. Methods: Data on 25(OH)D and pulmonary function from nine European ancestry (EA) cohorts (N=22,838) and five African ancestry (AA) cohorts (N=4,290) in the CHARGE Consortium was analyzed using linear models by cohort and ancestry group. Interaction terms tested effect modification of the 25(OH)D-pulmonary function association by smoking status (current/former/never). Results were combined using inverse variance weighted fixed-effects meta-analysis. Findings: Mean (SD) serum 25(OH)D was 68 (29) nmol/L for EAs and 49 (21) nmol/L for AAs. For each 10 nmol/L higher 25(OH)D (~0.5 SD), forced expiratory volume in 1 second (FEV 1 ) was higher by 11.1 mL (P=2.5×10 -21 ) in EAs and 17.9 mL (P=1.6×10 -7 ) in AAs. Forced vital capacity (FVC) was higher by 12.9 mL (P=1.1×10 -20 ) in EAs and 15.4 mL (P=1.2×10 -4 ) in AAs. The 25(OH)D-FEV 1 /FVC associations were negligible. Among EAs, the magnitude of the 25(OH)D-FVC association was stronger in smokers, as evidenced by association estimates of 17.3 mL for current smokers, 16.6 mL for former smokers, compared to 7.8 mL for never smokers, per 10 nmol/L higher 25(OH)D. Interpretation: The 25(OH)D associations with FEV 1 and FVC were consistently positive in both EAs and AAs, and the stronger magnitudes of the 25(OH)D-pulmonary function association among smokers support the importance of vitamin D in vulnerable populations. Funding: U.S. NIH R21HL125574 among others.