Aims: There is growing interest in the association between vitamin D and chronic lung diseases including asthma and COPD. We have in vivo experimental data suggesting that early life vitamin D deficiency has a strong impact on lung development. The aim of this study was to determine whether there is an association between maternal vitamin D status and post-natal lung function in children.

Methods: We conducted a sub-analysis of data collected as part of the West Australian Pregnancy (Raine) Cohort. Serum levels of 25(OH)D were measured at the time of recruitment (16–18 weeks gestation) and measured by immunoassay. Lung function was measured by spirometry at 6 and 14 years of age in children according to ATS guidelines at the time of collection. Linear regression was used to assess the association between maternal serum 25(OH)D and lung function (Z-scores; GLI reference equations). Logistic regression was used to assess associations between maternal vitamin D status and categorical outcomes (wheeze, asthma and atopy). Analyses were adjusted for relevant confounders (e.g. maternal asthma, SES, foetal growth).

Results: Maternal serum 25(OH)D was associated with 1) FVC Z-score (β[95% CI], 0.007[0.001, 0.013]; p = 0.02) in both sexes at 6 years of age, 2) FEV1 Z-score (β[95% CI], 0.007[0.001, 0.013]; p = 0.02) in females at 6 years of age and, 3) FEV1/FVC Z-score (β[95% CI], 0.012[0.000, 0.023]; p = 0.05) in females at 14 years of age. Maternal vitamin D deficiency was also associated with asthma (OR[95% CI], 3.03[1.02, 9.02]; p = 0.04) in males at 6 years of age.

Conclusions: Our analysis of data from a prospective community based cohort show sex specific associations between maternal vitamin D status and lung outcomes in children. These data support the notion that maternal vitamin D is an important determinant of early lung development.