Sleep duration, selected circulating biomarkers, and colorectal cancer risk

Sleep duration has been proposed to influence the risk of colorectal cancer (CRC). An involvement of inflammation, metabolic disorders, and gut permeability has been suggested. We investigated the relationship between sleep duration and CRC risk and examined whether sleep duration was associated with selected inflammatory and metabolic markers, and markers of gut permeability and bacterial translocation from the intestine to bloodstream. We used data from an Italian case-control study including 212 subjects (71 CRC cases and 141 tumor-free subjects). Sleep habits were collected through a questionnaire, including information on the average hours of sleep per night. We measured serum C-reactive protein (CRP) and glycemia by the ILab System, lipopolysaccharide-binding protein and zonulin by ELISA kit, and blood bacterial 16S rRNA gene copies by quantitative PCR and sequencing. We derived the odds ratios (OR) and corresponding 95% confidence intervals (CI) of CRC according to sleep duration from multiple logistic regression models. There was a positive association between long sleep duration and CRC risk, OR, 3.36 (95% CI, 1.08-10.53) for ≥ 9 compared to 7-8 h. For ≤ 6 h, the OR was 1.62 (95% CI, 0.84-3.29). BMI, circulating levels of CRP and glycemia, and a species of Streptococcus appeared to be higher in subjects reporting ≥9 vs. 7-8 h of sleep. Our data show a positive relationship between long sleep on CRC risk and suggest possible insights on inflammation, metabolic disorders, and possibly gut barrier dysfunction explaining this association.