Long Sleep Duration is Associated with Increased High-Sensitivity C-Reactive Protein: A Nationwide Study on Chinese...

High-sensitivity C-reactive protein (hs-CRP) has been shown as an important predictor of cardiovascular risk, and sleep duration is an important factor influencing health outcomes. However, the association between hs-CRP and sleep duration among Chinese adults remained unknown and controversial. We aimed to explore the associations between sleep duration and hs-CRP levels among Chinese adults, and the differences in sex and geographical regions.

This cross-sectional study was based on nationally representative Chinese samples from the 2009 China Health and Nutrition Survey, which employed multistage, random cluster designs. Habitual sleep duration was self-reported with short and long sleep duration defined as ≤6h and ≥9h per day, respectively. Participants were divided into 4 groups based on the categories of self-reported sleep duration (≤6h, 7h, 8h, ≥9h per day), excluding hs-CRP levels ≥10 mg/L. Subset samples were stratified by sex and geographical regions.

A total of 8170 Chinese adults with a mean age of 50.0±14.9 years and 4369 (53.5%) men were included. Participants sleeping eight hours had the lowest hs-CRP levels. Long sleep duration (≥9h) was significantly associated with elevated hs-CRP levels after adjusting for multiple covariates in full samples (β=0.0356; 95% CI: 0.0050-0.0663; P=0.0228), but the associations of short sleep duration (≤ 6h) were limited to the unadjusted model. Long sleep duration was associated with elevated hs-CRP levels in women (β= 0.0512; 95% CI: 0.0097-0.0927; P=0.0155) and in the northern region of China (β=0.0699; 95% CI: 0.0210-0.1187; P=0.0051), but not in men or the southern region.

Long but not short sleep duration was positively associated with elevated hs-CRP levels, independent from traditional risk factors among Chinese adults, and sex and geographical differences were observed. Our findings imply that modifications of long sleep duration might be added to behavioral therapy to reduce cardiovascular risk in Chinese adults.