Document Type
Article
Publication Date
1-1-2017
Abstract
Background: The vitamin D receptor (VDR) gene is expressed abundantly in different tissues; including adipocytes and pancreatic beta cells. The rs1544410 or BsmI single nucleotide polymorphism (SNP) in the intronic region of the VDR gene has been previously associated with vitamin D levels, obesity and insulin resistance. Aims: This study was aimed to examine the association between BsmI polymorphism and risk of vitamin D deficiency, obesity and insulin resistance in adolescents living in a tropical country. Methods: Thirteen-year-old adolescents were recruited via multistage sampling from twenty-three randomly selected schools across the city of Kuala Lumpur, Malaysia (n = 941). Anthropometric measurements were obtained. Obesity was defined as body mass index higher than the 95th percentile of the WHO chart. Levels of fasting serum vitamin D (25-hydroxyvitamin D (25(OH)D)), glucose and insulin were measured. HOMA-IR was calculated as an indicator for insulin resistance. Genotyping was performed using the Sequenom MassARRAY platform (n = 807). The associations between BsmI and vitamin D, anthropometric parameters and HOMA-IR were examined using analysis of covariance and logistic regression. Result: Those with AA genotype of BsmI had significantly lower levels of 25(OH)D (p = 0.001) compared to other genotypes. No significant differences was found across genotypes for obesity parameters. The AA genotype was associated with higher risk of vitamin D deficiency (p = 0.03) and insulin resistance (p = 0.03) compared to GG. The A allele was significantly associated with increased risk of vitamin D deficiency compared to G allele (adjusted odds ratio (OR) = 1.63 (95% Confidence Interval (CI) 1.03–2.59, p = 0.04). In those with concurrent vitamin D deficiency, having an A allele significantly increased their risk of having insulin resistance compared to G allele (adjusted OR = 2.66 (95% CI 1.36–5.19, p = 0.004). Conclusion: VDR BsmI polymorphism was significantly associated with vitamin D deficiency and insulin resistance, but not with obesity in this population.
Keywords
Adolescent, Anthropometry, Female, Genetic Association Studies, Genetic Predisposition to Disease, Humans, Insulin Resistance, Malaysia, Male, Obesity, Polymorphism, Single Nucleotide, Receptors, Calcitriol, Vitamin D Deficiency
Divisions
fac_med
Funders
High Impact Research, Ministry of Higher Education Grant, Malaysia (HIR H00021-00-E000082),University Malaya Research Grant (RG310-11HTM)
Publication Title
PLoS ONE
Volume
12
Issue
6
Publisher
Public Library of Science