Oral and Poster Presentation 45th Annual ARA NSW-ACT Branch Meeting 2023

Smoking, obesity and use of hormone replacement therapy are associated with rheumatoid arthritis in Australian women (#26)

Louise Koller-Smith 1 , Ahmed Mehdi 2 , Lyn March 3 , Leigh Tooth 4 , Gita D Mishra 5 , Ranjeny Thomas 1
  1. The University of Queensland Frazer Institute, Woolloongabba, Queensland
  2. Queensland Cyber Infrastructure Foundation Ltd, Facility for Advanced Bioinformatics,, Brisbane, Queensland
  3. Florance and Cope Professorial Department of Rheumatology, Royal North Shore Hospital, Sydney, New South Wales
  4. School of Public Health, The University of Queensland, Brisbane, Queensland
  5. University of Queensland, School of Public Health, University of Queensland, Brisbane, Queensland

Background: Up to 40% of rheumatoid arthritis (RA) cases are attributable to potentially modifiable factors, representing a valuable opportunity for prevention if such factors can be recognised and reduced. While some factors, particularly smoking/particulate inhalation, obesity, low levels of physical activity, periodontitis, sugar sweetened soda consumption and low levels of breastfeeding, have been identified in US and European cohorts, many remain unstudied, and evidence is lacking on such factors in the Australian context. The data on the impact of hormone replacement therapy (HRT) are mixed between studies. To provide the first risk factor estimates for RA in Australia, we studied RA cases and controls identified in the nationally representative Australian Longitudinal Study on Women’s Health (ALSWH), a prospective cohort of 41,638 women across Australia, ongoing since 1996, and using linked administrative data from the Pharmaceutical Benefits Scheme (PBS), Medicare Benefits Schedule (MBS) and hospital/emergency department (ED) data.

 

Aim: To provide estimates of association between RA and smoking, HRT use, obesity, and alcohol use in ALSWH participants.

 

Methods: ALSWH participants were identified from dispensed medications for RA from linked PBS data (2002 onward) (Treated RA, tRA) and hospital and ED episodes coded for RA (2005 onward) (Documented RA, dRA). Autoantibody status was not available. Data on HRT use, BMI, alcohol intake and smoking were extracted from the ALSWH surveys and PBS data and compared between RA cases and all non-RA survey participants using Chi square tests, and odds ratios (OR) and 95% confidence intervals were calculated.

 

Results: Of 40,393 included ALSWH participants, 745 met treated RA criteria and 292 met documented RA criteria. Risk factors significantly associated with RA were ever smoking [ORs tRA 1.43, (1.15-1.78), dRA 1.35 (1.00-1.87)], current HRT use [ORs tRA 1.45 (1.09-1.93), dRA 1.84 (1.23-2.76)], ever HRT use [ORs tRA 1.40 (1.05-1.88), dRA 1.98 (1.32-3.02)] and obesity [ORs tRA 1.41 (1.08-1.84), dRA 1.67 (1.15-2.41)]. Drinking ³1 standard drink/week was not associated with RA.

 

Conclusion: These univariate estimates show positive associations between smoking, HRT use and obesity but not alcohol consumption and RA. Future research will clarify these associations with multivariate analyses and in incident RA cases.