Association of vitamin D receptor gene polymorphisms with susceptibility to childhood asthma: A meta-analysis

BackgroundAs for the association of vitamin D receptor (VDR) gene polymorphisms with susceptibility to pediatric asthma, results of published studies yielded conflicts. A systematic review was conducted on the relationship between childhood asthma and VDR gene polymorphisms, including ApaI (rs7975232), BsmI (rs1544410), FokI (rs2228570), and TaqI (rs731236). MethodsPubMed, Web of Science, CBM (Chinese Biomedical Database), CNKI (China National Knowledge Infrastructure), and Wanfang (Chinese) database were searched for relevant studies. Pooled odds ratios (OR) with 95% confidence interval (CI) were calculated. ResultsOverall results suggested that there was a statistically significant association between ApaI polymorphism and childhood asthma in homozygote model (OR=1.674, 95%CI=1.269-2.208, P<0.001) and allele model (OR=1.221, 95%CI=1.084-1.375, P=0.001). Stratification by ethnicity revealed a statistical association in Asians (OR=1.389, 95%CI=1.178-1.638, P<0.001). There was some evidence of an association between BsmI polymorphism and childhood asthma in the homozygote (OR=1.462, 95%CI=1.016-2.105, P=0.041) and allele models (OR=1.181, 95%CI=1.006-1.386, P=0.042). This association reached significance only in the Caucasian group (OR=1.236, 95%CI=1.029-1.485, P=0.023). For FokI, a statistical association was detected in dominant model (OR=1.281, 95%CI=1.055-1.555, P=0.012); this association was significant in allele model (OR=1.591, 95%CI=1.052-2.405, P=0.028) in Caucasian. ConclusionApaI polymorphism plays a particular role in childhood asthma in Asians. FokI polymorphism may be connected with pediatric asthma in Caucasian population. And BsmI polymorphism marginally contributes to childhood asthma susceptibility, while there might be no association between TaqI polymorphism and childhood asthma risk. Pediatr Pulmonol. 2017;52:423-429. (c) 2016 Wiley Periodicals, Inc.