Abstract / Summary
Abstract Background Multisite pain is common among older adults and may reflect broader health vulnerability beyond pain at a single anatomical site. However, longitudinal evidence on the associations of pain-site distribution with subsequent functional and psychological outcomes among older Chinese adults remains limited. We examined whether the anatomical extent of baseline pain was associated with incident activities of daily living (ADL) limitation and depressive symptoms over two years. Methods We analyzed data from the 2018 and 2020 waves of the China Health and Retirement Longitudinal Study, including 9,728 adults aged ≥ 60 years in the overall longitudinal cohort. Pain-site count was categorized as 0, 1–2, or ≥ 3 painful sites. Incident ADL limitation was assessed among 7,389 participants without baseline ADL limitation. For incident depressive symptoms, baseline and follow-up CESD-10 scores were handled using multiple imputation, resulting in analytic samples of 5,991–6,044 participants across 50 imputed datasets. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Restricted cubic spline analyses were used to assess potential nonlinear associations. Results Compared with participants without pain, those with pain at 1–2 sites had higher odds of incident ADL limitation (OR 1.40, 95% CI 1.18–1.65) and incident depressive symptoms (OR 1.35, 95% CI 1.14–1.59). Stronger associations were observed among participants with pain at ≥ 3 sites, with ORs of 2.56 (95% CI 2.23–2.95) for incident ADL limitation and 2.06 (95% CI 1.77–2.40) for incident depressive symptoms. Graded associations were observed across pain categories for both outcomes (both P for trend < 0.001). Restricted cubic spline analyses showed significant overall associations with both outcomes (both P for overall association < 0.001), with evidence of nonlinearity for incident ADL limitation ( P = 0.007) and incident depressive symptoms ( P < 0.001). Conclusions Greater anatomical involvement of pain was associated with higher odds of incident ADL limitation and depressive symptoms among older Chinese adults. Pain-site count may provide complementary information regarding subsequent functional and psychological vulnerability, although it should be interpreted as a marker of anatomical pain extent rather than a diagnostic or prognostic threshold. Given the observational design, these findings do not establish causal relationships.