Relationship between Sleep Duration and Osteoarthritis in Middle-Aged and Older Women: A Nationwide Population-Based Study

(1) Background: Both long and short sleep durations have been associated with negative health outcomes, particularly in middle-aged and older adults. To date, there has been little research on the association between sleep and osteoarthritis. This study aimed to evaluate the relationship between sleep duration and radiographically confirmed osteoarthritis in middle-aged and older women. (2) Methods: This study included 5268 women aged ≥50 years from the Korea National Health and Nutrition Examination Survey. Sleep duration was categorized into four groups (≤5 h, 6 h, 7⁻8 h, and ≥9 h) using responses from a self-reported questionnaire, and 7⁻8 h was set as an appropriate sleep duration. Osteoarthritis was defined as Kellgren⁻Lawrence grade ≥2 in the knee or hip area in radiographic images with knee or hip joint pain. The odds ratios (ORs) and 95% confidence intervals (CIs) of osteoarthritis according to sleep duration were calculated using multiple logistic regression analyses. (3) Results: The prevalence of osteoarthritis according to sleep duration showed a U-shaped curve, with the nadir in the appropriate sleep category (7⁻8 h). Compared with the 7⁻8 h sleep duration, the ORs (95% CIs) of osteoarthritis in the short sleep duration (≤5 h/day) and long sleep duration (≥9 h/day) were 1.343 (1.072⁻1.682) and 1.388 (1.020⁻1.889), respectively, after adjusting for age, body mass index, current smoking, alcohol consumption, regular exercise, occupation, residential area, hypertension, type 2 diabetes, cardiovascular disease, and stroke. (4) Conclusions: Short and long sleep duration were positively associated with osteoarthritis in middle-aged and older women.