Investigation of genetic variation and lifestyle determinants in vitamin D levels in Arab individuals

• Published in: Journal of translational medicine Vol. 16; no. 1; pp. 20 - 6
• Main Authors: Mezzavilla, Massimo, Tomei, Sara, Alkayal, Fadi, Melhem, Motasem, Ali, Maisa M., Al-Arouj, Monira, Bennakhi, Abdullah, Alsmadi, Osama, Elkum, Naser
• Format: Journal Article
• Language: English
• Published: London BioMed Central 30.01.2018; BioMed Central Ltd; BMC
• Subjects: Arab population; Arabs; Biomedical and Life Sciences; Biomedicine; Computational Modelling and Epidemiology; GC gene; Genetic aspects; Medicine/Public Health; Physiological aspects; Recursive partitioning analysis; Single nucleotide polymorphisms; Vitamin D; Qatar; Arab population; Recursive partitioning analysis; GC gene; Vitamin D
• ISSN: 1479-5876; 1479-5876
• DOI: 10.1186/s12967-018-1396-8

Background Differences in the concentrations of circulating 25-hydroxyvitamin D [25(OH)D] are associated with a wide range of health outcomes; however, most studies on genetic variants that impact 25(OH)D levels have been conducted in European populations. Here we aimed to identify common genetic variants that affect vitamin D concentrations in individuals of self-reported Arab ethnicity. Methods The study included 1151 Arab subjects living in Kuwait. Common variants of single-nucleotide polymorphisms and genes previously associated with vitamin D levels, such as GC, PDE3B, CYP2R1, and NADSYN1, were genotyped. Raw vitamin D level data were corrected for age, body mass index, and sex and then normalized. Regression tree analyses were performed to identify the impact of genetic variants on vitamin D levels. Results Compared with other gene variants, the GC gene variants exhibited the greatest impact on vitamin D levels in our study population, of which rs2298850 had the lowest p value (0.003). Individuals homozygous for the derived allele C had lower vitamin D levels. Analyses of the interaction between the number of years for which the subjects had lived in Kuwait and genetic variation in the GC gene showed that those with the CC genotype of rs2298850 who had lived in Kuwait for < 51 years had a mean 25(OH)D level of 10 ng/ml, whereas those who were homozygous for the ancestral allele had a mean 25(OH)D level of 17 ng/ml. Furthermore, subjects who had lived in Kuwait for > 51 years had higher vitamin D levels (mean 28 ng/ml) regardless of the genotype of their GC gene. Conclusions The GC gene may play a major role in determining vitamin D levels in Arab populations.