(P30-026-25) Vitamin D Status in Pregnancy and Its Association With Offspring Lung Function and Asthma at Age 12: An Odense Child Cohort Study

Objectives: Vitamin D deficiency (serum 25-hydroxyvitamin D₂₊₃ (s-25(OH)D)) < 25nmol/L in pregnancy can impair embryonic lung and immune system development, potentially affecting the children's lung function and the risk of childhood asthma. We aimed to assess whether s-25(OH)D levels in pregnancy were associated with offspring lung function and asthma at age 12-years.

Methods: This population-based prospective cohort study, nested in a case-control study in Odense Child Cohort, included children with (n=87) or without (n=163) questionnaire-based suspicion of asthma and available spirometry at 12 years of age and s-25(OH)D from early pregnancy, late pregnancy or cord blood. The diagnoses of current and/or cumulated childhood asthma were validated through a structured interview incl. symptoms, medications and previous physician diagnosis, and clinical examinations. Multiple regression and two-stage mixed models adjusted for relevant covariates were used to examine associations.

Results: Acceptable/usable spirometry were obtained in 250 children (FVC n=240, FEV₁ n=245) and and early, late pregnancy and cord blood s-25(OH)D was available in 180, 222 and 250 children, respectively. 35 children had validated current asthma, and 78 children had validated cumulated asthma. The mean (SD) s-25(OH)D in early pregnancy, late pregnancy, and cord blood was 64.9 (18.9)nmol/L, 78.5 (26.1)nmol/L, and 47.9 (21.4)nmol/L respectively. The mean (SD) Z-score for FVC was -0.44 (0.82), FEV₁ -0.48 (0.85), and FEV₁/FVC -0.05 (1.03). The odds ratio (95%CI) for validated cumulated childhood asthma was 17.281 (1.002;298.1), P=0.050 for early pregnancy s-25(OH)D < 25 (n=3) vs. 50-74.9nmol/L. S-25(OH)D did not associate with FEV₁, FVC, FEV₁/FVC or current asthma.

Conclusions: Marginal associations between low early pregnancy s-25(OH)D and the risk of cumulated childhood asthma was detected, however, no associations between s-25(OH)D and lung function or current asthma at age 12 were found. Cohorts with more prevalent maternal vitamin D deficiency should be studied.

Funding Sources: This research was funded by Børnelungefonden (spirometry), Odense University Hospitals Undergraduate fund (salary to CCL Rosenørn) and Frimodt-Heineke Foundation (expenses related to publication and presentation of the results).