Risk Factors Of Rheumatoid Arthritis Development Among Females In North-West Of Iran: A Case-Control Study

Background: Given the high prevalence of rheumatoid arthritis (RA) in females of reproductive ages, it seems that hormonal factors might be important in RA pathogenesis.Objectives: The current study aimed to investigate the association between females' reproductive factors occurring prior to the onset of rheumatoid arthritis and the risk of RA development.Methods: This case-control study was conducted on 231 patients with RA and 238 controls among females aged 26-64 years old from the North-West of Iran. The adjusted risk of RA was assessed using multivariate logistic regression models.Results: Females >= 14 years old at menarche, were more likely to be at risk of RA (OR = 1.69; 95% CI: 1.08 - 2.64). Advanced maternal age at first delivery (OR = 1.91; 95% CI: 1.21 - 3.26) and having abortion (OR = 1.97; 95% CI: 1.23 - 2.99) significantly increased the risk of RA. Post-menopausal status increased the risk of developing RA (OR = 2.97; 95% CI: 1.98 - 4.46). Longer duration of breast-feeding was determined as significant protective variable for RA (P < 0.05). Subjects with oral contraceptives (OCs) use (OR = 0.36; 95% CI: 0.20 - 0.64), parity (OR = 0.20; 95% CI: 0.06 - 0.70) or large number of children tended to show rather more reduced risk of RA.Conclusions: The risk of RA increased with delayed menarche, advanced maternal age at first delivery and early age at menopause. However, longer duration of breast-feeding, parity, large number of children and consumption of OCs were found as protective independent variables against RA.