1.
Associations between vitamin D receptor polymorphisms and susceptibility to ulcerative colitis and Crohn's disease: a meta-analysis.
Xue, LN, Xu, KQ, Zhang, W, Wang, Q, Wu, J, Wang, XY
Inflammatory bowel diseases. 2013;(1):54-60
Abstract
BACKGROUND Several polymorphisms have been identified in the vitamin D receptor (VDR) gene, while their roles in the incidence of ulcerative colitis (UC) and Crohn's disease (CD) are conflicting. This meta-analysis was designed to clarify the impact of these polymorphisms on UC and CD risk. METHODS The PubMed, Embase, and Cochrane electronic databases were searched from February 1995 to August 2011 for studies on the four VDR polymorphisms: TaqI, BsmI, FokI, and ApaI. Data were extracted and pooled odd ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. RESULTS Nine studies were included. In Asians, the ff genotype of FokI was associated with increased UC risk (OR = 1.65; 95% CI, 1.11- 2.45). The "a" allele carrier status of ApaI appeared to be a protective factor for CD (OR = 0.81; 95% CI, 0.67-0.97). The tt genotype increased the risk of CD in Europeans (OR = 1.23; 95% CI, 1.02-1.49). Moreover, the tt genotype of TaqI in males had a moderate elevated risk of UC (OR = 1.56; 95% CI, 1.02-2.39) and CD (OR = 1.84; 95% CI, 1.19-2.83). CONCLUSIONS The meta-analysis reveals a significant increase in CD risk for Europeans carrying TaqI tt genotype and a significant decrease in CD risk for all carriers of the Apal "a" allele. For Asians, the VDR FokI polymorphism appears to confer susceptibility to UC. For males, the TaqI tt genotype is associated with susceptibilities to both UC and CD. Our study explored the genetic risk prediction in UC and CD, and may provide valuable insights into IBD therapy.
2.
Quantitative assessment of the associations between four polymorphisms (FokI, ApaI, BsmI, TaqI) of vitamin D receptor gene and risk of diabetes mellitus.
Wang, Q, Xi, B, Reilly, KH, Liu, M, Fu, M
Molecular biology reports. 2012;(10):9405-14
Abstract
The vitamin D receptor (VDR) gene polymorphisms have been suggested to be involved in the development of diabetes mellitus, including type 1 diabetes (T1DM) and type 2 diabetes (T2DM). However, the results have been inconsistent. In this study, we performed a meta-analysis to investigate the associations. Literature was retrieved from PubMed, ISI Web of Science and Chinese databases. Pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated using a random or fixed effect model. 79 studies (FokI: 22 studies; BsmI: 25 studies; ApaI: 17 studies; TaqI: 15 studies) on T1DM and 44 studies (FokI: 10 studies; BsmI: 10 studies; ApaI: 14 studies; TaqI: 10 studies) on T2DM were included. The results indicated that BsmI polymorphism was associated with an increased risk of T1DM (B vs. b: OR 1.31, 95 % CI 1.10-1.55, P = 0.002), especially in East Asians (B vs. b: OR 2.57, 95 % CI: 1.55-4.24, P < 0.001); FokI polymorphism was associated with an increased risk of T2DM (f vs. F: OR 1.30, 95 % CI: 1.17-1.45, P < 0.001), especially in East Asians (f vs. F: OR 1.36, 95 % CI: 1.21-1.54, P < 0.001). However, no significant association was observed between ApaI or TaqI polymorphism and diabetes risk with the exception of significant association between ApaI polymorphism and T1DM risk in East Asians. Thus, the authors found BsmI polymorphism in the VDR gene may increase the risk of T1DM in East Asians and the FokI polymorphism may increase the risk of T2DM in East Asians.