Strong association of the polymorphisms in PBEF1 and knee OA risk: a two-stage populationbased study in China

The association of Pre-B cell colony enhancing factor 1 (PBEF1) with obesity, together with its pro-inflammatory properties suggests that PBEF1 might be another crucial mediator that links inflammation with obesity and primary osteoarthritis (OA). We hypothesized that polymorphisms in PBEF1 may modify the risk of developing OA. Thus we systematically screened 4 tagging polymorphisms (rs4730153, rs2058540, rs3801267 and rs16872158) in PBEF1 and evaluated the association between the genetic variants and OA risk in a two-stage case-control study including 196 cases and 442 controls in the first stage and 143 cases and 238 controls in the second stage. In the first stage, two SNPs (rs4730153 and rs16872158) were found to be potentially associated with OA risk (P < 0.05), which were further confirmed in the second stage with similar effects. After combining the two stages, we found that rs4730153 was significantly associated with decreased risk of OA in an additive genetic model (P < 0.05), while rs16872158 showed increased risk of developing OA (P < 0.05). Combined analysis of these 2 SNPs showed a significant allele-dosage association between the number of risk alleles and OA risk (P-trend = 5.25 x 10(-5)). These findings indicate that genetic variants in PBEF1 gene may modify individual susceptibility to OA in the Chinese population.