Sleep Duration and Cancer Risk: a Systematic Review and Meta-analysis of Prospective Studies

Abstract

To assess the risk of cancers associated with sleep duration using meta-analysis of published cohort studies, we performed a comprehensive search using PubMed, Embase and Web of Science through October 2013. We combined hazard ratios (HRs) from individual studies using meta-analysis approaches. A random effect dose-response analysis was used to evaluate the relationship between sleep duration and cancer risk. Subgroup analyses and sensitivity analyses were also performed. Publication bias was evaluated using Funnel plots and Begg's test. A total of 13 cohorts from 12 studies were included in this meta-analysis, which included 723, 337 participants with 15, 156 reported cancer outcomes during a follow-up period ranging from 7.5 to 22 years. The pooled adjusted HRs were 1.06 (95% CI: 0.92, 1.23; P for heterogeneity =0.003) for short sleep duration, 0.91 (95% CI: 0.78, 1.07; P for heterogeneity <0.0001) for long sleep duration. In subgroup analyses stratified by cancer type, long duration of sleep showed an inverse relation with hormone-related cancer (HR=0.79; 95% CI: 0.65, 0.97; P for heterogeneity =0.009) and a greater risk of colorectal cancer (HR=1.29; 95% CI: 1.09, 1.52; P for heterogeneity =0.346). Further meta-analysis on dose-response relationships showed that the relative risks of cancer were 1.00 (95% CI: 0.99, 1.01; P for linear trend=0.9151) for one hour of sleep increment per day, and 1.00 (95% CI: 0.98, 1.01; P for linear trend=0.7749) for one hour of sleep increment per night. No significant dose-response relationship between sleep duration and cancer was found on non-linearity testing (P=0.5053). Our meta-analysis suggests a positive association between long sleep duration and colorectal cancer, and an inverse association with incidence of hormone related cancers like those in the breast. Studies with larger sample size, longer follow-up times, more cancer types and detailed measure of sleep duration are warranted to confirm these results.

Associations among rotating night shift work, sleep and skin cancer in Nurses' Health Study II participants

“…22 A meta-analysis investigating the association between sleep duration and cancer risk (skin cancer was not included) found a positive association for colorectal cancer and a negative association for hormone-related cancers such as those of the breast. 23 However, a recent study found no clear relationship between sleep duration and melanoma. 6 In the current study, we controlled for menopausal status and hormone use.…”

Sleep duration and cancer risk in women

“…This interest has been fueled by the fact that over a third of the U.S. population reports insufficient sleep [4] and mounting scientific evidence that sleep disturbances are associated with increased risks of a number of chronic health conditions, including cardiovascular disease, diabetes, and cancer [5-13]. To date, the limited number of published studies on sleep duration and cancer risk have yielded provocative, yet highly inconsistent results, reporting elevated risks associated with both short and long sleep durations as well as no associations for a variety of cancer sites [14-31].…”

“…To date, the limited number of published studies on sleep duration and cancer risk have yielded provocative, yet highly inconsistent results, reporting elevated risks associated with both short and long sleep durations as well as no associations for a variety of cancer sites [14-31]. These inconsistencies may partially be a reflection of different mechanistic pathways operating for different cancer sites [13]. The objective of the current study was to conduct an analysis of sleep duration and risk of all cancer sites combined, as well as for the five most commonly-diagnosed cancer sites among a large, prospective cohort of California women.…”

Association between sleep-disordered breathing, obstructive sleep apnea, and cancer incidence: a systematic review and meta-analysis

“…Although two systematic reviews have supported an association between duration of sleep and risk of cancer [13,14], a review by Lu et al refuted an overall association [15], not excluding the existence of a positive association in specific cancer subtypes. Although most studies that assessed the association between SDB and cancer supported a positive association [16][17][18][19][20], evidence contrary to this also exists [21].…”