Numerous original studies and 4 published meta-analyses have reported the association between the Vitamin D receptor (
VDR
) BsmI, FokI, ApaI, and TaqI polymorphisms and type 2 diabetes mellitus (T2DM) risk. However, the results were inconsistent. Therefore, an updated meta-analysis was performed to further explore these issues.
To further explore the association between the
VDR
BsmI, FokI, ApaI, and TaqI polymorphisms and T2DM risk.
PubMed, EMBASE, Scopus, and Wanfang databases were searched. The following search strategy were used: (
VDR
OR vitamin D receptor) AND (polymorphism OR variant OR mutation) AND (diabetes OR mellitus OR diabetes mellitus). Pooled crude odds ratios with 95% confidence intervals were applied to evaluate the strength of association in 5 genetic models. Statistical heterogeneity, the test of publication bias, and sensitivity analysis were carried out using the STATA software (Version 12.0). To evaluate the credibility of statistically significant associations, we applied the false-positive report probabilities (FPRP) and Bayesian false discovery probability (BFDP) test.
Overall, the
VDR
BsmI polymorphism was associated with a significantly decreased T2DM risk in Asians; the
VDR
FokI polymorphism was associated with a significantly decreased T2DM risk in Asians, African countries, and Asian countries; the
VDR
ApaI polymorphism was associated with a significantly decreased T2DM risk in Caucasians and North American countries.
On the
VDR
ApaI polymorphism, a significantly increased T2DM risk was found in a mixed population. However, when we further performed a sensitivity analysis, FPRP, and BFDP test, less-credible positive results were identified (all FPRP > 0.2 and BFDP > 0.8) in any significant association.
In summary, this study strongly indicates that all significant associations were less credible positive results, rather than from true associations.