Association between sleep duration and osteoarthritis and their prevalence in Koreans: A cross-sectional study

OBJECTIVE: To determine the association of radiological and symptomatic osteoarthritis with sleep duration in a representative sample of the Korean population. METHODS: Using data from the national cross-sectional fifth Korea National Health and Nutrition Examination Survey 2010–2012. Of the 16,528 participants in KNHANES-V, 8,918 were adults aged≥ 50 years who had completed the survey questions on sleep duration and osteoarthritis, and had diagnostic X-ray results. We evaluated the association between sleep duration as the primary predictor for osteoarthritis involving the hip, knee, and spinal joints. A complex sample logistic regression analysis was performed to adjust for the covariates. RESULTS: Proportions of participants with total daily sleep duration of ≤6 hours, 7–8 hours, and ≥9 hours were 47.1%, 45.2, and 7.7%, respectively. The rate of osteoarthritis diagnoses in the ≤6 hours, 7–8 hours, and ≥9 hours of sleep duration groups was 24.1%, 17.6%, and 21.8%, respectively (p <0.0001). The odds ratios (OR) were significantly higher in the ≤6 hours of sleep group than in the 7–8 hours of sleep group (OR, 1.20; 95% confidence interval [CI], 1.03–1.39; p = 0.02), but no significant difference in the ≥9 hours of sleep group was found after adjusting the confounding variables. When we compared knee joint pain (Numeric Rating Scale 0 versus 1–10) in participants with grade 2–4 Kellgren-Lawrence (KL) classification after adjusting these same confounding variables, the ≤6 hours of sleep group (OR, 1.32; 95% CI, 1.10–1.58) and the ≥9 hours of sleep group (OR, 1.41; 95% CI, 1.03–1.95) showed significantly higher ORs. CONCLUSION: This study confirmed the significant association between sleep duration and osteoarthritis in adults aged ≥50 years. Participants’ positive for both radiological (KL grade ≥2) and symptomatic osteoarthritis showed a strong association between knee joint pain and not enough sleep duration.