Association of estrogen receptor α gene polymorphisms with bone mineral density in Chinese women:: a meta-analysis

Introduction and hypothesis A large number studies have examined the association between estrogen receptor alpha (ESR-alpha) gene polymorphisms and bone mineral density (BMD) in the Chinese population. We conducted a meta-analysis to assess their pooled effects. Methods We searched for all published articles indexed in MEDLINE, the Chinese Biomedical Database, and the Chinese Journal Full-text Database from January 1994 to April 2006. Any cross-sectional study that tested the association between ESR-alpha PvuII or XbaI genotypes and BMD at the femoral neck or spine in Chinese women was included in the review. Data were extracted independently by two reviewers using a standardized data extraction form. Sixteen eligible studies involving 4,297 Chinese women were identified. Results The overall frequencies of X and P alleles were 28% and 40%, respectively. The PvuII polymorphism was statistically significantly associated with BMD at the femoral neck (P = 0.038 for PP = Pp = pp) but not at the lumbar spine in all women. The BMD difference for the contrasts of PP versus Pp/pp genotypes was -0.0105 (95%CI, -0.0202 similar to -0.0008) g/cm(2) (P = 0.036). The XbaI polymorphism was not associated with BMD at the femoral neck or lumbar spine. Conclusion The PvuII polymorphism had a very weak association with femoral neck BMD whereas XbaI polymorphism was unlikely to be a predictor of femoral neck or spine BMD in Chinese women.