Association of vitamin D pathway gene polymorphisms with vitamin D level during pregnancy was modified by season and vitamin D supplement.

BACKGROUND & AIMS: This study aims to explore the associations of vitamin D (VD) metabolic pathway gene with 25(OH)D level in pregnant women and the interactions of SNP with season and VD supplement.

METHODS

A total of 2658 pregnant women were selected from Zhoushan Pregnant Women Cohort study. Gestational 25(OH)D level and single nucleotide polymorphism (SNP) of VD metabolic pathway gene were detected. Multilinear regression models were used to estimate associations of SNPs with gestational 25(OH)D levels. Stratified analyses were performed to test the interactions of SNP with season and VD supplements.

RESULTS

The mutations of rs2298849 and rs7041 on the GC gene were respectively associated with higher 25(OH)D in the first and third trimester; the mutations of seven SNPs (rs1155563, rs16846876, rs17467825, rs2282679, rs2298850, rs3755967, and rs4588) on the GC gene were respectively associated with lower 25(OH)D both in the first and third trimester, and lower changes in 25(OH)D during late pregnancy. The mutations of above seven SNPs, except for rs1155563, were also respectively associated with lower 25(OH)D in the second trimester, but to a lesser extent; Besides, pregnant women with mutation on CYP24A1-rs2209314 had a higher increment in 25(OH)D than their counterparts in the second trimester. The increasing dose effect of Gc isoform on 25(OH)D was observed. The associations of GC and LRP2 genes with 25(OH)D modified by season and VD supplements.

CONCLUSIONS

The polymorphisms of VD metabolic pathway gene were associated with gestational 25(OH)D, and the associations differ by seasons and VD supplements. Gc isoform exerted a profound influence on gestational 25(OH)D.