Association between Vitamin D-Related Gene Polymorphisms and Serum 25-Hydroxyvitamin D Levels: A Prospective Cohort Study in West Sumatra, Indonesia

Background: Several candidate genes in vitamin D synthesis and metabolism have reported a significant association with 25-hydroxyvitamin D (25(OH)D) in Caucasians and African Americans. Few studies have indicated this relationship among Asian, especially in West Sumatran pregnant women, Indonesia. Methods: The study was conducted among 186 singleton pregnant mothers of West Sumatran Vitamin D Pregnant Mother (VDPM) cohort study, were recruited and followed from the first trimester ((T1) to delivery process (~9 months). Serum 25(OH)D obtained during T1 and T3. Genetic risk scores (GRS) were created based on six vitamin D–related SNPs and their association with 25(OH) D levels were tested. Information on demographics, lifestyle, pregnancy profile, dietary intake, and physical activity was collected using a questionnaire. Results: Mean serum 25(OH)D levels in T1 and T3 levels were 14.00 ± 6.98 and 21.21 ± 10.41 ng/mL, respectively. Vitamin D-GRS has significantly associated with serum 25(OH)D levels in the third trimester (P = 0.004) and changes 25(OH)D levels during pregnancy (P = 0.018), but not in the first trimester. However, synthesis-GRS and metabolism-GRS group of vitamin D genetic variants pathway had no effect in 25(OH)D levels and changes 25(OH)D levels during pregnancy (P > 0.05). High prevalence of low maternal vitamin D status during pregnancy commonly found in the first trimester. Conclusion: We observed an association between vitamin D-GRS and 25(OH)D levels during pregnancy. Our results provide additional support for a possible role of genetic variation in vitamin D-related genes on vitamin D status during pregnancy. Further replication studies utilizing larger sample sizes are needed to confirm our findings.