Rahmadhani Rayinda, Zaharan Nur Lisa, Mohamed Zahurin, Moy Foong Ming, Jalaludin Muhammad Yazid
Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Julius Centre University of Malaya, Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
PLoS One. 2017 Jun 15;12(6):e0178695. doi: 10.1371/journal.pone.0178695. eCollection 2017.
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.
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.
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.
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).
VDR BsmI polymorphism was significantly associated with vitamin D deficiency and insulin resistance, but not with obesity in this population.
维生素D受体（VDR）基因在不同组织中大量表达，包括脂肪细胞和胰岛β细胞。VDR基因内含子区域的rs1544410或BsmI单核苷酸多态性（SNP）先前已与维生素D水平、肥胖和胰岛素抵抗相关。
本研究旨在探讨BsmI多态性与生活在热带国家的青少年维生素D缺乏、肥胖和胰岛素抵抗风险之间的关联。
通过多阶段抽样从马来西亚吉隆坡市随机选取的23所学校招募13岁青少年（n = 941）。进行人体测量。肥胖定义为体重指数高于世界卫生组织图表的第95百分位数。测量空腹血清维生素D（25-羟基维生素D（25(OH)D））、血糖和胰岛素水平。计算HOMA-IR作为胰岛素抵抗指标。使用Sequenom MassARRAY平台进行基因分型（n = 807）。采用协方差分析和逻辑回归检验BsmI与维生素D、人体测量参数和HOMA-IR之间的关联。
与其他基因型相比，BsmI的AA基因型者的25(OH)D水平显著更低（p = 0.001）。各基因型在肥胖参数方面未发现显著差异。与GG基因型相比，AA基因型与维生素D缺乏风险更高（p = 0.03）和胰岛素抵抗风险更高（p = 0.03）相关。与G等位基因相比，A等位基因与维生素D缺乏风险增加显著相关（调整比值比（OR）= 1.63（95%置信区间（CI）1.03 - 2.59，p = 0.04）。在同时存在维生素D缺乏的人群中，与G等位基因相比，携带A等位基因显著增加其胰岛素抵抗风险（调整OR = 2.66（95% CI 1.36 - 5.19，p = 0.004）。
在该人群中，VDR BsmI多态性与维生素D缺乏和胰岛素抵抗显著相关，但与肥胖无关。
