Growing evidence links extremes of self-reported sleep duration with higher circulating markers of inflammatory disease risk, although not all findings are consistent. Extremes of sleep duration also associate with activation… Click to show full abstract
Growing evidence links extremes of self-reported sleep duration with higher circulating markers of inflammatory disease risk, although not all findings are consistent. Extremes of sleep duration also associate with activation of the hypothalamic-pituitary-adrenocortical (HPA) system and the peripheral release of cortisol, a glucocorticoid (GC) important in downregulating transcription of pro-inflammatory molecules. Polymorphic variation in the gene encoding the GC receptor (GR; NR3C1) modulates cellular sensitivity to GC-mediated anti-inflammatory signaling, thereby affecting levels of pro-inflammatory molecules. Thus, we hypothesized that extremes of self-reported sleep duration may covary with circulating levels of inflammatory markers as a function of allelic variation in NR3C1. Specifically, we examine the possibility that a single nucleotide polymorphism of the GR gene-(rs6198), the minor (G) allele of which confers reduced GR sensitivity-moderates an association of sleep duration with interleukin (IL)-6 and C-reactive protein (CRP) among a large sample (IL-6: N = 857; CRP: N = 929) of midlife community volunteers of European ancestry. Findings showed that sleep duration varied inversely with IL-6 (β = -0.087, p = .012), and this association was stronger among individuals homozygous for the rs6198 G-allele compared to alternate genotypes (β = -0.071, p = .039). We also found that sleep duration showed a U-shaped association with CRP (polynomial term: β = 0.093, p = .006), which was not moderated by rs6198 genotype. In conclusion, we show that a common genetic variant in the GR moderates an inverse association of self-reported sleep duration with circulating IL-6, possibly contributing to the increased disease risk observed among some short sleepers.
               
Click one of the above tabs to view related content.