Sleep Duration and Cancer in the NIH-AARP Diet and Health Study Cohort

BACKGROUND Very few studies have examined sleep duration in relation to cancer incidence with the exception of breast cancer. METHODS We assessed the associations between sleep duration and incidences of total and 18 site-specific cancers in the NIH-AARP Health and Diet Study cohort, with 173,327 men and 123,858 women aged 51-72 years at baseline. Self-reported sleep duration categories were assessed via questionnaire. We used multivariable Cox proportional hazards regression to estimate hazard ratios (HR) and 95% confidence intervals (CI), using 7-8 hours/night as the reference. RESULTS We observed a significantly increased risk of stomach cancer among male short sleepers (multivariable HR5-6 vs. 7-8 hours = 1.29; 95%CI: 1.05, 1.59; Ptrend = 0.03). We also observed suggestive associations in either short or long sleepers, which did not reach overall significance (Ptrend >0.05), including increased risks in male short sleepers for cancers of head and neck (HR<5vs.7-8 hours = 1.39; 95%CI:1.00-1.95), bladder (HR5-6vs.7-8 hours = 1.10; 95%CI:1.00-1.20), thyroid (HR<5 vs. 7-8 hours = 2.30; 95%CI:1.06, 5.02), Non-Hodgkin Lymphoma (NHL) (HR5-6vs.7-8 hours = 1.17; 95%CI:1.02-1.33), and myeloma (HR<5vs.7-8 hours = 2.06; 95%CI:1.20-3.51). In women, the suggestive associations include a decreased total cancer risk (HR<5vs.7-8 hours = 0.9; 95%CI:0.83-0.99) and breast cancer risk (HR<5vs.7-8 hours = 0.84; 95%CI:0.71-0.98) among short sleepers. A decreased ovarian cancer risk (HR≥ 9 vs. 7-8 hours = 0.50; 95%CI:0.26-0.97) and an increased NHL risk (HR≥ 9 vs. 7-8 hours = 1.45; 95%CI:1.00-2.11) were observed among long sleepers. CONCLUSION In an older population, we observed an increased stomach cancer risk in male short sleepers and suggestive associations with short or long sleep duration for many cancer risks in both genders.