The Association Between Knee Osteoarthritis and Fracture Risk in Women Aged 50 and Older: A Population-Based Cohort Study

초록

Objective: Osteoarthritis (OA) and osteoporosis are prevalent disorders in elderly women, sharing common risk factors such as menopause and aging. Research on the relationship between these conditions showed variable associations depending on the specific site of osteoarthritis. Previous studies on knee OA‒the most common form of OA‒ showed higher bone mineral density compared to those without. However, the relationship between knee OA and fracture risk still controversial; these inconsistent results may be due to differences in the demographic and clinical characteristics of the study populations. Our study aims to address this gap by focusing on Asian women aged 50 and above. Material and methods: We used cohort data from the National Health Insurance Service of Korea between 2010 and 2018. Women aged 50 and older, without prior OA before 2010, or conditions such as cancer, rheumatoid arthritis, and with available body mass index (BMI) data, were included. Patients with knee OA were matched at a 1:2 ratio with non-knee OA participants based on age, BMI, and the index year using propensity score matching. Results: 49,198 patients with knee OA were compared with 98,396 non-knee OA controls. The mean age of the study population was 61.9 ± 9.6 years, and the mean BMI was 23.4 ± 2.8 kg/m2. During an average of 9.1 years follow-up, knee OA groups had a 21% higher fracture risk compared to the non-knee OA group, with a significantly higher risk in the first two years after diagnosis. Walking exercise, the use of osteoporosis medication, and calcium or vitamin D supplements were associated with a reduced risk of fractures than the non-use groups (p for interaction < 0.05). Conclusion: Knee OA was associated with an increased risk of fractures in women aged 50 and over, particularly shortly after diagnosis. Walking exercise and the use of osteoporosis medications might be beneficial. Further research is needed, but early management of osteoporosis in knee OA patients could be beneficial.