Blunted rest-activity rhythm is associated with increased white blood-cell-based inflammatory markers in adults: an...

Circadian rhythm disruption is associated with immune system disturbance and has been observed in many health problems where chronic-inflammation acts as a major contributor. We aim to examine whether rest-activity circadian rhythm is associated with chronic inflammation using white blood-cell-based inflammatory indices including white blood cell (WBC) count, neutrophil count, neutrophil-to-lymphocyte ratio (NLR) and systemic immune-inflammation index (SII). We analyzed the data from 8089 adults (age≥20) with at least 4 days of validated accelerometer recordings and a valid WBC count from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Non-parametric rest-activity circadian rhythm parameters were derived from the accelerometer recordings. In the models adjusting multiple covariates, a one-quantile increase in relative amplitude (i.e. more robust circadian rhythm) was associated with 1 × 10⁸ cells/L decrease in WBC number (95% CI: 5 × 10⁷ to 1.5 × 10⁸, P < .001), 7 × 10⁷ cells/L decrease in neutrophils (95% CI: 3 × 10⁷ to 1.1 × 10⁸, P = .003) and 15.2 × 10⁹ /L decrease in SII (95% CI: 6 × 10⁹ /L to 20 × 10⁹/L, P = .019). Consistent results were also observed for the association of M10 value and L5 value with these inflammatory indices. Our results indicated that blunted rest-activity circadian rhythm is associated with increased white blood-cell-based inflammatory indices in adults, suggesting interventions aiming at enhancing circadian rhythm by lifestyle programs may be a novel approach to improve the general health.