Rheumatoid arthritis (RA) is complex autoimmune system disease and significant impact on the health of population in our world. Numerous studies confirmed that genetic factors play a crucial role in the pathogenesis of RA. In this current study, we aimed to investigate IL-6 polymorphisms and RA risk in Chinese Han population.
508 RA patients and 494 age- and gender- matched healthy controls were recruited, all subjects were genotyped with an Agena MassARRAY platform. Subsequently, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression after adjusting for age and gender.
Our results suggested that IL-6 rs2243289 allele and genotype frequencies were associated with reduced RA risk under all genetic models (all p < 0.05). Stratification analysis revealed that IL-6 rs2243289 polymorphism was significant associated with decreased the risk of RA in the old groups (age > 54) (all p < 0.05). However, IL-6 rs2069837 and rs1800796 polymorphisms were associated with increased risk of RA among the young groups (age ≤ 54) (all p < 0.05). In addition, subgroup analysis by gender suggested that IL-6 rs2069837 and rs1800796 polymorphism were interacted with increased the risk of RA in males (all p < 0.05). Besides, IL-6 rs2243289 was associated with reduced RA risk in females.
In conclusion, our results demonstrated the correlation between IL and 6 polymorphisms and RA susceptibility and confirmed for the first time that the relationship was restricted to age and gender in Chinese Han population.