Diurnal Variation of Circulating Interleukin-6 in Humans: A Meta-Analysis
2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 11, e0165799Article in journal (Refereed) Published
The pleiotropic cytokine interleukin-6 (IL-6) has been proposed to contribute to circadian regulation of sleepiness by increasing in the blood at night. Earlier studies have reported diurnal variation of IL-6, but phase estimates are conflicting. We have therefore performed a meta-analysis on the diurnal variation of circulating IL-6. Studies were included if they reported IL-6 in plasma or serum recorded at least twice within 24 hours in the same individual. A systematic search resulted in the inclusion of 43 studies with 56 datasets, for a total of 1100 participants. Individual participant data were available from 4 datasets with a total of 56 participants. Mixed-effects meta-regression modelling confirmed that IL-6 varied across the day, the most conspicuous effect being a trough in the morning. These results stand in contrast to earlier findings of a peak in the evening or night, and suggest that diurnal variation should be taken into account in order to avoid confounding by time of day in studies of IL-6 in plasma or serum.
Place, publisher, year, edition, pages
2016. Vol. 11, no 11, e0165799
Environmental Health and Occupational Health Clinical Laboratory Medicine
IdentifiersURN: urn:nbn:se:su:diva-135822DOI: 10.1371/journal.pone.0165799ISI: 000387725000035PubMedID: 27832117Local ID: P-3377OAI: oai:DiVA.org:su-135822DiVA: diva2:1049342