Association between polymorphisms in the estrogen receptor alpha gene and osteoarthritis susceptibility: a meta-analysis

BACKGROUND Osteoarthritis (OA) is a common chronic disease of the joints. Genetic factors may play a role in its development, and polymorphisms in the estrogen receptor alpha gene (ERα) have been associated with OA. However, previous studies into this relationship have reported inconsistent results, so we aimed to systematically review the association between ERα polymorphisms and OA susceptibility. METHODS We conducted a comprehensive literature search of Ovid MEDLINE, EMBASE, CBM, and PubMed databases, and Google scholar, and identified 11 eligible studies that examined the association between ERα polymorphisms and OA susceptibility. We carried out a meta-analysis of these studies based on ERα XbaI (rs9340799) and PvuII (rs2234693) genotypes. RESULTS Seventeen comparisons involving 10 European and seven Asian populations of 5,325 OA patients and 10,834 controls were included in the study. The ERα XbaI polymorphism were significantly associated with OA in Europeans (AA vs. AG + GG: OR = 1.17, 95% confidence interval (CI) = 1.02-1.34, P = 0.03; AG vs. AA + GG: OR = 0.86, 95% CI = 0.75-0.99, P = 0.04) but not in Asian populations. No association was found between OA and the ERα PvuII polymorphism in any population (C vs. T, OR = 0.98, 95% CI = 0.93-1.03, P = 0.37; CC vs. TT + CT, OR = 0.97, 95% CI = 0.89-1.06, P = 0.55; CT vs. CC + TT, OR = 0.99, 95% CI = 0.92-1.06, P = 0.75; TT vs. CC + CT, OR = 1.01, 95% CI =0.92-1.12, P = 0.79). CONCLUSIONS This study suggested that there may be a weak relationship between the ERα XbaI polymorphism and OA in Europeans but not Asians, and that the ERα PvuII polymorphism was not associated with OA in either population. However, large well-designed studies are necessary to confirm these results in more homogeneous populations.