Abstract
ObjectivesThis study was aimed to investigate the association of the single nucleotide polymorphism of tumor necrosis factor receptor associated factor 6 (TRAF6), rs540386, with low bone mineral density (BMD) among patients with rheumatoid arthritis (RA).MethodsTRAF6 rs540386 genotyping was performed by mutagenically separated PCR in a cohort of 188 (23 men, 165 women, median age, 56.2years) adult RA patients and 224 age and gender-matched controls. BMD was measured using dual-energy X-ray absorptiometry (DXA) (Lunar Prodigy advance scans, GE Healthcare, USA).ResultsAmong the RA patients, 64 (55 women, 9 men) had low BMD comprising of 57 patients with osteoporosis and 7 with osteopenia. Whereas TRAF6 rs540386 was not associated with RA susceptibility, it was however found to be a risk factor for reduced lumbar spine Z-score in the recessive model (OR=3.34, 95% CI=(1.01-11.00), p=0.038). This association was confirmed further in the multivariate logistic regression analysis taking into account several potential confounding factors (OR=3.34 (1.01-11.00), p=0.048). In addition, mean total femur Z-score was found to be reduced in TT patients when compared to CC + CT patients (-1.301.32 versus -0.60 +/- 1.05, p=0.034). No association between TRAF6 rs540386 and localbone damage was observed.Conclusions This study for the first time ever demonstrated an association between a genetic variant of TRAF6 and low BMD among patients with RA. Further investigations are needed to elucidate the exact role of this variant.