Influence of vitamin D binding protein polymorphism, demographics and lifestyle factors on vitamin D status in healthy Malaysian pregnant women

Abstract

Background Vitamin D deficiency (VDD) has been related to vitamin D binding protein (GC) gene polymorphism, demographics and lifestyle factors in different populations. However, previous studies examining the factors associated with VDD during pregnancy were restricted to the study of only demographics and lifestyle factors or genetic factors alone. Thus, this study assesses the associations of GC gene polymorphism, environmental and lifestyle factors with VDD in Malaysian pregnant women. Method: Information on demographics, dietary vitamin D intake from supplement and food, time spent outdoors, skin type and clothing were collected by questionnaire. Plasma total 25-hydroxyvitamin D (25OHD) levels were measured using Ultra-High-Performance Chromatography (UHPLC). Maternal GC single nucleotide polymorphisms (SNPs) (rs4588 and rs7041) were determined using restriction fragment length polymorphism (RFLP). Results Results showed that 50.2% of pregnant women were vitamin D deficient (25OHD < 30 nmol/L). VDD (25OHD < 30 nmol/L) were significantly associated with age, veiled clothing, maternal vitamin D intakes, both from food and supplement, and GC rs7041(and GC diplotypes). In contrast to previous studies in non-pregnant population, this study found that CC genotype for SNP GC rs7041, GC 1 s-1 s and GC If-2 were significantly associated with increased risk of VDD (25OHD < 30 nmol/L). Conclusions The high prevalence of maternal VDD reported in the present study suggests the need for urgent development and implementation of vitamin D supplementation or fortification strategies to reduce VDD among pregnant women. The discrepancy in the association of GC rs7041 with VDD reflects the differential in the factors associated with vitamin D deficiency in pregnancy compared to non-pregnant state