A I Hellevik1, L Nordsletten2, M B Johnsen3, A M Fenstad4, O Furnes5, K Storheim6, J A Zwart7, G Flugsrud8, A Langhammer9. 1. The HUNT Research Centre, Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Levanger, Norway; Division of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway. Electronic address: alf.hellevik@ntnu.no. 2. Division of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Norway. Electronic address: lars.nordsletten@medisin.uio.no. 3. Faculty of Medicine, University of Oslo, Norway; Research and Communication Unit for Musculoskeletal Health, Division of Clinical Neuroscience, Oslo University Hospital, Oslo, Norway. Electronic address: m.b.johnsen@medisin.uio.no. 4. The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway. Electronic address: anne.marie.fenstad@helse-bergen.no. 5. The Norwegian Arthroplasty Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, Institute of Medicine and Dentistry, University of Bergen, Bergen, Norway. Electronic address: ove.furnes@helse-bergen.no. 6. Faculty of Medicine, University of Oslo, Norway; Research and Communication Unit for Musculoskeletal Health, Division of Clinical Neuroscience, Oslo University Hospital, Oslo, Norway. Electronic address: kjersti.storheim@medisin.uio.no. 7. Faculty of Medicine, University of Oslo, Norway; Research and Communication Unit for Musculoskeletal Health, Division of Clinical Neuroscience, Oslo University Hospital, Oslo, Norway. Electronic address: j.a.zwart@medisin.uio.no. 8. Division of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway. Electronic address: gbflugsrud@gmail.com. 9. The HUNT Research Centre, Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Levanger, Norway. Electronic address: arnulf.langhammer@ntnu.no.
Abstract
OBJECTIVE: To investigate whether parity, age at menarche, menopausal status, age at menopause, use of oral contraceptives (OC) or use of hormone replacement therapy (HRT) were associated with total knee replacement (TKR) or total hip replacement (THR) due to primary osteoarthritis. METHOD: In a prospective cohort study of 30,289 women from the second and third surveys of the Nord-Trøndelag Health Study, data were linked to the Norwegian Arthroplasty Register (NAR) in order to identify TKR or THR due to primary osteoarthritis. Cox proportional hazards models were used to estimate the hazard ratios (HRs). RESULTS: We observed 430 TKRs and 675 THRs during a mean follow-up time of 8.3 years. Increasing age at menarche was inversely associated with the risk of TKR (P-trend < 0.001). Past users and users of systemic HRT were at higher risk of TKR compared to never users (HR 1.42 (95% confidence interval (CI) 1.06-1.90) and HR 1.40 (95% CI 1.03-1.90), respectively). No association was found between parity, age at menarche, menopausal status, age at menopause, oral contraceptive use or HRT use and THR. CONCLUSION: We found that increasing age at menarche reduced the risk of TKR. Past users and users of systemic HRT were at higher risk of TKR compared to never users. Parity did not increase the risk of THR or TKR.
OBJECTIVE: To investigate whether parity, age at menarche, menopausal status, age at menopause, use of oral contraceptives (OC) or use of hormone replacement therapy (HRT) were associated with total knee replacement (TKR) or total hip replacement (THR) due to primary osteoarthritis. METHOD: In a prospective cohort study of 30,289 women from the second and third surveys of the Nord-Trøndelag Health Study, data were linked to the Norwegian Arthroplasty Register (NAR) in order to identify TKR or THR due to primary osteoarthritis. Cox proportional hazards models were used to estimate the hazard ratios (HRs). RESULTS: We observed 430 TKRs and 675 THRs during a mean follow-up time of 8.3 years. Increasing age at menarche was inversely associated with the risk of TKR (P-trend < 0.001). Past users and users of systemic HRT were at higher risk of TKR compared to never users (HR 1.42 (95% confidence interval (CI) 1.06-1.90) and HR 1.40 (95% CI 1.03-1.90), respectively). No association was found between parity, age at menarche, menopausal status, age at menopause, oral contraceptive use or HRT use and THR. CONCLUSION: We found that increasing age at menarche reduced the risk of TKR. Past users and users of systemic HRT were at higher risk of TKR compared to never users. Parity did not increase the risk of THR or TKR.