MMP8 polymorphism is associated with susceptibility to osteonecrosis of the femoral head in a Chinese Han population

Osteonecrosis of the femoral head (ONFH) is an orthopedic refractory disease that adversely affects quality of life. Matrix metalloproteinase-8 (MMP-8) produced by the bone marrow has been implicated in the degradation of collagen during bone development. We assessed whether MMP8 polymorphisms are associated with ONFH. In a case-control study, using χ(2) tests and genetic model analyses, we genotyped 5 MMP8 single-nucleotide polymorphisms (SNPs) in 585 ONFH patients and 507 healthy control subjects in a Chinese Han population. The MMP8 rs11225394 SNP was associated with an increased risk of ONFH in an allele model (OR=1.34; 95% CI, 1.003-1.786, P=0.047). In addition, rs11225394 was associated with an increased risk of ONFH in a dominant model (OR =1.39, 95% CI, 1.02–1.89, P=0.036), over-dominant model (OR=1.39, 95% CI, 1.02–1.89, P=0.038), and log-additive model (OR =1.36, 95% CI, 1.01–1.84, P=0.039). After adjusting for age and gender, rs11225394 was associated with ONFH in a dominant (OR =1.44, 95% CI, 1.05–1.96, P=0.023), over-dominant (OR =1.44, 95% CI, 1.05–1.98, P=0.022), and log-additive model (OR =1.40, 95% CI, 1.04–1.90, P=0.027). These results provide the first evidence that MMP8 SNP at the rs11225394 locus is associated with the increased risk of ONFH in Chinese Han population.