Circadian syndrome as a multisystem risk factor for pain in older adults: Evidence from a cross-sectional and...

Circadian syndrome and pain are prevalent in aging populations, yet their relationship remains underexplored. This study investigates the cross-sectional and longitudinal associations between circadian syndrome and pain among older adults.

Data were drawn from three prospective cohorts: the China Health and Retirement Longitudinal Study, the English Longitudinal Study of Aging, and the US Health and Retirement Study. Pain severity was self-reported as mild, moderate, or severe. Multivariable logistic regression assessed cross-sectional associations, while generalized linear mixed models examined longitudinal relationships between baseline circadian syndrome and incident pain during follow-up. Subgroup and sensitivity analyses were conducted to confirm the reliability of the findings.

At baseline, 18,719 participants were included, comprising 7219 from the China Health and Retirement Longitudinal Study, 6063 from the English Longitudinal Study of Aging, and 5437 from the Health and Retirement Study. Cross-sectionally, individuals with circadian syndrome had significantly higher odds of prevalent pain than those without: the odds ratios were 1.68 (95% confidence interval 1.51-1.88) in the Chinese cohort, 2.24 (95% confidence interval 1.95-2.58) in the English cohort, and 1.71 (95% confidence interval 1.52-1.93) in the US cohort, suggesting a positive association between circadian syndrome and prevalent pain. In longitudinal analyses, baseline circadian syndrome predicted an increased risk of new-onset pain, with odds ratios of 1.26 (95% confidence interval 1.11-1.44) in the Chinese cohort, 1.62 (95% confidence interval 1.26-2.09) in the English cohort, and 1.22 (95% confidence interval 1.05-1.42) in the US cohort, providing stronger evidence for prospective prediction. Results remained robust across subgroup and sensitivity analyses.

This large-scale multinational study establishes circadian syndrome as a significant correlate of both prevalent and incident pain in older adults, highlighting the importance of multisystem circadian health in pain risk assessment.