Dual-Site Pain in the Low Back and Knee as a Risk Factor for Dementia: A Population-Based Cohort Study

Purpose: Chronic pain is a major public health concern and has been linked to cognitive decline. However, the effect of pain occurring simultaneously in two musculoskeletal sites on dementia risk remains unclear. In this study, we aimed to examine whether dual-site pain (DSP; in this study defined as cooccurring chronic low back and knee pain) is associated with an increased risk of dementia in community-dwelling older adults. Patients and Methods: We analyzed data from 2060 participants aged ≥ 65 years in the Locomotive Syndrome and Health Outcomes in the Aizu Cohort Study. DSP was defined as the presence of both chronic low back and knee pain lasting > 3 months. Participants without DSP served as the reference group. Incident dementia was identified from long-term care insurance certification records, and Cox proportional hazards models were used to estimate hazard ratios (HRs) adjusting for demographic and vascular risk factors, depressive symptoms, and physical activity. Results: Over 6 years, 197 participants (9.6%) developed dementia. The incidence was higher in the DSP group (16.5%, 26/158) than in the control group (9.0%, 171/1902). After adjustment, DSP remained significantly associated with dementia (HR = 1.57, 95% CI: 1.02– 2.42). Conclusion: Dual-site pain involving the low back and knee is a significant risk factor for dementia among older adults. Early identification and management of DSP may help preserve cognitive health, highlighting the need for integrated strategies addressing both musculoskeletal and cognitive well-being. Keywords: dual-site pain, dementia, epidemiology, cohort study