IL-6, sTNF-R2, and CRP in the context of sleep, circadian preference, and health in adolescents with eveningness chronotype: Cross-sectional and longitudinal treatment effects.

Background: Inflammation-related processes have emerged as a biological pathway related to adolescent development. This study examined cross-sectional and longitudinal associations of baseline inflammatory markers with sleep, circadian preference, and health at baseline and following treatment.

Methods: Participants included 165 adolescents (58.2% female, mean age 14.7 years, 42.4% taking medication) "at-risk" in at least one domain (emotional, cognitive, behavioral, social, and physical health) who received a sleep-based intervention. Self-reported eveningness as well as total sleep time (TST) and bedtime from sleep diary were assessed at baseline and following treatment. Baseline soluble tumor necrosis factor receptor-2 (sTNF-R2) and interleukin (IL)-6 were assayed from oral mucosal transudate. Baseline C-reactive protein (CRP) was assayed from saliva.

Results: At baseline, shorter TST was associated with more emotional risk among adolescents with higher CRP (b = -0.014, p = 0.007). Greater eveningness was related to more behavioral risk in the context of lower IL-6 (b = -0.142, p = 0.005). Following treatment, lower baseline IL-6 was associated with reduced behavioral risk (Χ = 8.06, p = 0.045) and lower baseline CRP was related to reduced physical health risk (Χ = 9.34, p = 0.025). Baseline inflammatory markers were not significantly associated with sleep, circadian, or other health domain change following treatment.

Conclusions: There was cross-sectional evidence that sleep and circadian dysfunction differentially relate to emotional and behavioral health risk for high and low levels of inflammatory markers. Longitudinal analyses indicated that lower levels of baseline inflammatory markers may be related to better treatment response to a sleep-based intervention.