OP0113 FEMALE REPRODUCTIVE FACTORS AND RISK OF JOINT REPLACEMENT ARTHROPLASTY OF KNEE AND HIP DUE TO OSTEOARTHRITIS IN POSTMENOPAUSAL WOMEN: A NATIONWIDE COHORT STUDY OF 1.36 MILLION WOMEN

Background:Previous studies on the link between female reproductive factors and osteoarthritis (OA) have shown conflicting results.Objectives:This study attempted to explore the association between reproductive factors and joint replacement arthroplasty of knee (TKRA) and hip (THRA) in a large nationwide population-based cohort of postmenopausal women.Methods:1,218,257 subjects who participated in national health examination in 2009 were included in the study. The study outcomes is incident THRA or TKRA due to severe hip or knee OA. The association of reproductive factors and THRA or TKRA was evaluated using a multivariate-adjusted proportional hazards model.Results:During the mean follow-up duration of 8.2 years, 1,733 incident THRA cases and 65,108 incident TKRA cases were observed. Later age at menarche (aHR 1.12 in 13-14 years; aHR 1.24 in 15-16 years; aHR 1.32 in ≥ 17 years), longer breastfeeding (aHR 1.24 in < 6 months; aHR 1.24 in 6-12 months; aHR 1.50 in ≥ 12 months), HRT (aHR 1.06 in < 2 years; aHR 1.11 in 2-5 years; aHR 1.21 ≥ 5 years) and OC use (aHR 1.11 in < 1 year; aHR 1.17 ≥ 1 year) was associated with increased risk of TKRA for severe knee OA, while later age at menopause (aHR 0.93 in 45-49 years; aHR 0.89 in 50-54 years), longer reproductive span (aHR 0.91 in 30-34 years; aHR 0.87 in 35-39 years; aHR 0.91 in ≥ 40 years) was associated with decreased risk. With regard to THRA for severe hip OA, later menarche (aHR 1.21 ≥ 17 years), longer breastfeeding (aHR 1.39 in < 6 months; aHR 1.31 in ≥ 12 months), and HRT more than 5 years (aHR 1.49) were associated with higher risk. The association between reproductive factors and severe OA was more pronounced in underweight and younger subjects.Conclusion:Our study found that shorter estrogen exposure was associated with higher risk of joint replacement therapy due to severe OA, and such association was more pronounced in underweight and younger subjects.Disclosure of Interests:None declared