Background RA preferentially affects women, with peak incidence coinciding with the menopausal years; however, the contribution of hormonal exposure prior to disease onset remains unclear.
Objectives To assess whether early age at menopause (EM, defined as age at menopause < 45) as compared to a usual age at menopause (UM, defined as age at menopause of 45 or older) affects disease presentation in post-menopausal (PM) women presenting with new onset early RA.
Methods PM women from the Canadian early ArThritis CoHort (CATCH)under age 65 at time of enrollment were included. The Wilcoxon rank sum test was applied to continuous variables and Chi-square test to categorical variables. Multivariate logistic regression analysis was used to select significant variables associated with EM and adjust for confounders, including smoking due to its association with both EM and seropositvity.
Results 534 women met inclusion criteria with 93 reporting EM and 441 reporting UM. The mean age (SD) at study entry was 55.5 (5.3) and did not differ between the two groups. The mean ages (SD) at menopause in the EM group and UM group were 38.5 (6.5) and 51.7 (3.5) (p<0.001). The mean DAS-28 score was 5.0 (1.5) and did not differ significantly between EM and UM groups. Compared to the UM group, the EM group was less likely to have completed high school (33.3% vs. 52.8%) (p<0.001) and was more likely to be current smokers (33.3% vs. 20.9%) (p<0.01). The EM group was more likely to report current use of hormone replacement therapy (HRT) (21.1% vs. 8.4%) (p<0.001). The EM group reported higher mean (SD) patient global scores (6.6 (2.9) vs. 5.8 (2.8)) (p<0.01) and pain scores (6.5 (2.7) vs. 5.6 (2.6)) (p<0.002). The EM group was more likely to meet 1987 criteria for RA (75.0% vs. 63.0%) (p<0.03) and have positive serologies for RF (71.6% vs. 55.0%) (p<0.01) and CCP (60.7% vs. 46.5%) (p<0.05). There was a non-significant trend for women to have more erosions in the EM group (31.0% vs. 23.6%) (p=0.19). The EM and UM groups did not differ in ESR/CRP, number of tender or swollen joints, fatigue, function (HAQ), physician global, symptom duration, or fulfillment of 2010 criteria for RA. Multivariate logistic regression analysis confirmed that women in the EM group were more likely to be current users of HRT and be RF positive, even after adjusting for smoking status (see Table 1).
Conclusions These data suggest that EM compared to UM is associated with different features at disease presentation in women with early RA. Further research is needed and ongoing to understand how changes in hormonal status and duration of menopause and estrogen exposure may affect autoimmunity and inflammation.
Disclosure of Interest L. Wong: None Declared, J. Xiong: None Declared, G. Boire: None Declared, B. Haraoui: None Declared, J. Pope: None Declared, J. Thorne: None Declared, C. Hitchon: None Declared, D. Tin: None Declared, E. Keystone: None Declared, V. Bykerk Grant/research support from: The CATCH study was designed and implemented by the investigators and financially supported initially by Amgen Canada Inc. and Pfizer Canada Inc. via an unrestricted research grant since inception of CATCH. As of 2011, further support was provided by Hoffmann-La Roche Ltd., United Chemicals of Belgium (UCB) Canada Inc., Bristol-Myers Squibb Canada Co., Abbvie Inc., and Janssen Biotech Inc. (a wholly owned subsidiary of Johnson & Johnson Inc).