Sleep duration and breast cancer risk among black and white women

Abstract

Background Sleep has been suggested to influence breast cancer risk, however the evidence is mixed. Black women have higher prevalence of both short (<6 hr) and long (≥9 hr) sleep duration and are more likely to develop more aggressive, hormone receptor negative breast cancer. No study has examined the relationship between sleep and breast cancer in blacks. We focused on race-specific associations among the blacks. Methods In the Southern Community Cohort Study (SCCS), a prospective study of which 2/3 of the population were black, we prospectively investigated self-reported sleep duration in relation to overall breast cancer risk and by estrogen (ER) and progesterone receptor (PR) status in all women and in black women alone. Results Sleep duration was not associated with risk of total or hormone receptor positive breast cancer. However, we found a suggestion of an inverse relationship between sleep duration and risk of ER− and PR− breast cancer among all women and black women. Compared to the reference group (8 hr), black women who reported shorter sleep had an increased risk of ER−PR− breast cancer (odds ratios (95% confidence intervals): 2.13 (1.15, 3.93), 1.66 (0.92, 3.02) and 2.22 (1.19, 4.12) for <6, 6 and 7 hr, respectively, p for trend, 0.04). Conclusion Short sleep may be a risk factor for hormone receptor negative breast cancer among black women.

Female Breast Cancer: Socio-Demographic, Lifestyle, and Clinical Risk Factors - A Hospital-Based Study in Two Egyptian Governorates

“…Finally, we illustrated that sleep duration <6 hour/day was insignificant risk factor for FBC (OR=1.26). It shown that short sleep duration might be a risk factor for hormone receptor-negative FBC [66]. The present study illustrated that high consumption of fat rich foods represented a significant risk factor for FBC (OR=2.48).…”

“…Further, it is expected that the cumulative incidence of FBC in the developed areas would be lowered by more than one half, from 6.3% to 2.7% by age 70, if females had the mean number of births and lifetime duration of breast-feeding that have been found in the developing areas till recently. Breast-feeding could account for almost 66.0% of the expected lowered in FBC incidence [10]. Trends in lifestyle factors vary greatly between different settings.…”

Do Older Adults Need Sleep? A Review of Neuroimaging, Sleep, and Aging Studies

“…Sleep loss increases susceptibility to the common cold [21], alters gene expression [22], and affects metabolism [23]. Moreover, in epidemiological studies, sleep disturbances are associated with cardiovascular conditions [24], cancer [25], Type II diabetes [26], and Alzheimer’s disease [27]. Because these conditions are more prevalent with advancing age, sleep alterations might explain many deleterious effects generally attributed to aging (hereafter, the preserved-sleep-need view).…”

Sleep quality, duration, and breast cancer aggressiveness

“…Particularly, African Americans have a higher rates of both long (>9 hours) and short sleep (<5 hours) compared to whites [12]. A recent study showed that black women with shorter sleep duration had a higher risk of ER-negative and PR-negative breast cancer [13]. Also, the higher incidence of aggressive breast tumors in African Americans and the potential for varying risk factors according to tumor type drives the current study.…”