Influence of a single nucleotide polymorphism (rs12785878) on vitamin D deficiency in pregnant women near delivery : a logistic regression analysis

Abstract

Background: Vitamin D deficiency is common among pregnant women in Switzerland. A deficiency has serious consequences for both the mother and the foetus. Genetic variants, such as single nucleotide polymorphisms (SNP), can influence vitamin D levels in pregnant women. This thesis investigates the effect of the SNP rs12785878 in gene 7-dehydrocholesterol reductase (DHCR7) on vitamin D deficiency in Swiss pregnant women in the third trimester. Methods: This thesis uses data from a Swiss cross-sectional study that took place between 2014 and 2016. The target group included pregnant women shortly before delivery at the Zurich University Hospital (n=138). Socio-demographic and vitamin D related information were collected by a questionnaire and blood samples. A multivariate logistic regression is used to answer the research question. Results: 52.17% of the sample is vitamin D deficient. The logistic model is adjusted for current BMI, supplementation of vitamin D, country of origin and skin type. The probability of vitamin D deficiency decreases with the presence of at least one T allele in the SNP rs12785878 [OR: 0.39, 95%-CI: 0.14 - 1.02]. Conclusion: The findings of this thesis indicate a link between a T allele in rs12785878 and a lower risk of vitamin D deficiency in pregnant women in Switzerland. Although not statistically significant, rs12785878 may play a role in vitamin D status. Future studies should focus on larger cohorts, regional differences, and additional predictors such as cholesterol metabolism. Standardised thresholds for defining vitamin D deficiency would improve comparability across studies and lead to more robust findings.