Circadian Syndrome Linked to Higher Risk of Multisite Pain in Chinese Adults

A large longitudinal study of middle-aged and older adults in China has found that people with circadian syndrome—a cluster combining short sleep duration, depressive symptoms, and metabolic abnormalities—were significantly more likely to develop multisite pain over the following years. The research, published in BMC Public Health, drew on baseline data from 2011 in the China Health and Retirement Longitudinal Study (CHARLS), with pain assessments in 2013 and 2015 providing up to four years of follow-up.

Among 6,124 participants who were initially free of multisite pain, 1,514—or 24.7 percent—went on to develop multisite pain during follow-up. In the fully adjusted primary analysis, using modified Poisson regression with robust standard errors, circadian syndrome was associated with a higher risk of new multisite pain, with a risk ratio of 1.19 (95 percent confidence interval: 1.09 to 1.30). The association held up in a 2015-only analysis (risk ratio 1.16, 95 percent CI: 1.04 to 1.30) and in a stricter analysis that excluded anyone with any baseline pain, including single-site pain (risk ratio 1.18, 95 percent CI: 1.07 to 1.31).

Circadian syndrome was defined as the presence of at least four of seven components, spanning short sleep, depressive symptoms measured with the 10-item Center for Epidemiologic Studies Depression Scale, and metabolic abnormalities. Because the study team wanted to know whether the composite definition itself carried information beyond its individual parts, they examined each component separately and ran leave-one-component-out analyses, in which the syndrome was redefined each time with one component removed. Depressive symptoms showed the strongest component association with incident multisite pain, with a risk ratio of 1.86, followed by short sleep at a risk ratio of 1.41.

The leave-one-out results proved revealing. When depressive symptoms were removed from the circadian syndrome definition, the association with incident multisite pain largely disappeared, attenuating to a risk ratio of 1.04 (95 percent CI: 0.95 to 1.13)—a range that includes no effect. This suggests that depressive symptoms accounted for much of the apparent association between the composite syndrome and future multisite pain, with short sleep contributing as well.

The researchers also tested whether circadian syndrome improved prediction beyond conventional risk factors. Adding the syndrome to a conventional model changed the tenfold cross-validated area under the receiver operating characteristic curve only modestly, from 0.669 to 0.672—a small gain in discrimination. Supplementary analyses strengthened the robustness of the work: Cox models were used because pain onset was interval-censored, and the team additionally applied inverse-probability-of-selection weighting, survey-weighted estimates, alternative thresholds for the syndrome definition, a flexible score model, a discrete-time model, and extended confounder adjustment.

The authors conclude that baseline circadian syndrome was associated with incident multisite pain among adults initially free of multisite pain—though not necessarily free of all pain, since those with single-site pain were retained in the main cohort. However, the component and leave-one-component-out analyses indicate that depressive symptoms and short sleep drove much of the association, and the composite added little predictive discrimination beyond conventional factors. They therefore caution that circadian syndrome should be interpreted as a marker of co-occurring vulnerabilities rather than as evidence of an independent integrated mechanism behind multisite pain.

Subject of Research: The prospective association between circadian syndrome and incident multisite pain among middle-aged and older Chinese adults in CHARLS.

Article Title: Circadian syndrome and incident multisite pain among middle-aged and older Chinese adults: component-specific and longitudinal analyses from CHARLS

Article References: Deng, Q. (2026). Circadian syndrome and incident multisite pain among middle-aged and older Chinese adults: component-specific and longitudinal analyses from CHARLS. BMC Public Health. https://doi.org/10.1186/s12889-026-30026-3

Image Credits: AI Generated

DOI: 10.1186/s12889-026-30026-3

Keywords: circadian syndrome, multisite pain, CHARLS, depressive symptoms, short sleep, metabolic abnormalities, risk ratio, longitudinal study, middle-aged adults, older adults, China, BMC Public Health