Association between vascular endothelial growth factor gene polymorphisms and the risk of osteonecrosis of the femoral head: Systematic review.

Emerging evidence has shown that vascular endothelial growth factor (VEGF) gene polymorphisms are the key initiators that regulate the expression of the VEGF protein, which has a vital role in osteonecrosis of the femoral head (ONFH). The aim of the present study was to investigate whether polymorphisms of the VEGF genes are associated with the occurrence of ONFH. A comprehensive search was performed on MEDLINE, Embase, Web of Science and China National Knowledge Infrastructure databases before June 2015. Meta-analyses were carried out for the VEGF gene -634G/C polymorphisms (single-nucleotide polymorphism with 3 eligible studies). The pooled odds ratios with 95% confidence intervals (CIs) were used to evaluate the strength of the association. All the eligible studies, involving 1,564 individuals, were identified. According to the inclusion criteria, 3 case-control studies were finally included in the meta-analysis. The present meta-analysis indicates that the VEGF gene -634G/C polymorphism [CC+GC vs. GG: Response rate (RR)=0.79; 95% CI, 0.67-0.92; GG vs. GC: RR=0.83; 95% CI, 0.72-0.97; GG vs. CC: RR=0.82; 95% CI, 0.72-0.93] is associated with the occurrence of ONFH, and the association with the male subgroup (RR=0.78; 95% CI, 0.65-0.94; P=0.009) is more evident. In conclusion, the present meta-analysis suggests that the VEGF gene -634G/C polymorphism has a significant association with ONFH occurrence among the investigated patients (P<0.01).