The interactive influences of sleep duration and activities of daily living on low back pain: Insights from CHARLS

OBJECTIVES: To quantify interactions between sleep duration and activities of daily living (ADL) limitations on low back pain (LBP) in Chinese adults ≥45 years using China Health and Retirement Longitudinal Study (CHARLS) data. METHODS: This study presents a cross-sectional analysis of CHARLS data collected between 2011 and 2015. Participants self-reported their sleep duration and LBP experiences. ADL limitations were assessed using a 12-item scale. Logistic regression analysis was used to evaluate the interaction effects of sleep duration and ADL limitations on LBP. RESULTS: Short sleep (OR = 1.50, 95 % CI 1.32, 1.70), basic activities of daily living (BADL) limitation (OR = 2.22, 95 % CI 1.68, 2.95), and instrumental activities of daily living (IADL) limitation (OR = 2.01, 95 % CI 1.72, 2.36) were independently associated with LBP. Multiplicative interactions were significant for short sleep with BADL (OR = 3.03, 95 % CI 1.97, 4.67) and IADL (OR = 1.94, 95 % CI 1.53, 2.45), and for long sleep with BADL (OR = 2.54, 95 % CI 1.41, 4.56) and IADL (OR = 1.62, 95 % CI 1.20, 2.18). Additive synergy was found in adults ≥60 years with short sleep and BADL (RERI = 2.81, AP = 0.56, S = 3.32), while long sleep and IADL showed antagonism (RERI = -1.30, AP = -0.68, S = 0.41). CONCLUSION: In adults ≥60 years, short sleep combined with BADL limitation exhibits an additive interaction on LBP, while long sleep combined with IADL limitation shows antagonism. Therefore, longitudinal studies are needed for causality and targeted interventions.