Sleep duration and the risk of prostate cancer: the Ohsaki Cohort Study

Abstract

In a prospective study of prostate cancer incidence (127 cases), among 22 320 Japanese men, sleep duration was associated with lower risk; the multivariate hazard ratio of men who slept X9 h per day compared with those who slept less was 0.48 (95% confidence interval: 0.29 -0.79, P for trend ¼ 0.02). Pinheiro et al, 2006). Melatonin, which is secreted mainly from the pineal gland and plays a role in sleep duration, is suggested as one of the candidates responsible for the association in breast cancer (Brzezinski, 1997;Schernhammer and Schulmeister, 2004) as it influences the synthesis and secretion of sex hormones by promoting the release of gonadotropin-releasing hormone (Martin and Klein, 1976;Aleandri et al, 1996).In relation to melatonin, there have been several observational studies of night work, shift work or visual impairment, and sex hormone-related cancers such as prostate or breast (Feychting et al, 1998;Verkasalo et al, 1999;Kliukiene et al, 2001;Megdal et al, 2005;Kubo et al, 2006;Conlon et al, 2007;Schwartzbaum et al, 2007). However, there has been no study of sleep duration and prostate cancer risk, even though prostate cancer, like breast cancer, is also a sex hormone-related cancer.We therefore examined the association between sleep duration and prostate cancer risk in a population of Japanese men, in whom the mortality of prostate cancer is increasing (Statistics and Information Department, Minister's Secretariat, Ministry of Health Labour and Welfare of Japan, 2007). MATERIALS AND METHODSDetails of the Ohsaki National Health Insurance (NHI) Cohort Study have been described previously (Tsuji et al, 1998;Kuriyama et al, 2006). Briefly, this prospective cohort study was started in 1994 and included 26 481 men aged 40 -79 years living in the 14 municipalities of Miyagi Prefecture, northeastern Japan. The response rate was 94.0% (N ¼ 24 895) for the questionnaire that was self-administered and included items about sleep duration and other health-related lifestyle factors. The study protocol was reviewed and approved by the ethics committee of Tohoku University School of Medicine.After exclusion of subjects who had withdrawn from the NHI before follow-up, those who had a history of cancer, those who had omitted responses for sleep duration, and those who had reported sleep duration of less than 4 h or more than 12 h, 22 320 subjects remained. To follow-up participants for mortality and migration, we reviewed the NHI withdrawal history files for 1995 -2001. Through the Miyagi Prefectural Cancer Registry, we identified 127 incident cases of prostate cancer. During the study period, there had been no mass screening programme for prostate cancer in this area. Clinical stage was classified according to the TNM system as localised (T1 -T2), advanced (T3 -T4), metastatic (N þ and/or M þ ), or unknown.With regard to the sleep duration, participants answered the mean integer number of hours of sleep per day during the last year. Because of the small number who slept for less than 7 h and more than 8 h, we c...

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

“…Finally, 12 articles fulfilling the inclusion criteria were included in the meta-analysis. Among these 12 articles, five studies reported breast cancer (Verkasalo et al, 2005;Pinheiro et al, 2006;Kakizaki et al, 2008b;Vogtmann et al, 2013;Wu et al, 2013), two studies on colorectal cancer (Jiao et al, 2013;Zhang et al, 2013), one each study on prostate cancer (Kakizaki et al, 2008a), endometrial cancer (Sturgeon et al, 2012), epithelial ovarian cancer (Weiderpass et al, 2012), thyroid cancer (Luo et al, 2013), and all type cancers (von Ruesten et al, 2012).…”

“…The study samples ranged from 12, 222 to 142, 933, and the median of the follow-up durations is 11.3 years. Nine studies focused on the cancer of women, one only on men (Kakizaki et al, 2008a), one on men and women combined (von Ruesten et al, 2012), and one reporting men and women separately according to different cohorts (Zhang et al, 2013). Most of studies reported the sleep duration of 24 hours period, while four studies investigated typical night sleep duration (Sturgeon et al, 2012;Jiao et al, 2013;Luo et al, 2013;Vogtmann et al, 2013).…”

Sleep duration and cancer risk: time to use a “sleep-years” index?

“…Dr. Sturgeon et al [4] now provide the sixth study on the issues concerned and report mixed results. Overall, with regard to how long one sleeps, first [4][5][6][7][8]-but not all [9]-epidemiological evidence could be viewed in line with increased cancer risks in those who sleep less than others [2].…”

Cancer incidence vs. population average sleep duration on spring mattresses

“…See Table III for an example with calculations explained. Figure 5 graphs the relationship between sleep duration and breast cancer in Japan and Singapore [10,14], as well as prostate cancer in Japan [11].In order to test the hypothesis, that incident and reflected waves of horizontally polarized radiation cancel each other close to a metal structure and might add as standing waves further up from it, we measured the electric fields of FM-radio signals above beds with and without a metal spring mattress. A horizontal monopole antenna (0.5 metre) was connected to spectrum analyser (GW Instek, GSP 827, Taiwan).…”

“…Despite increasing screening and lifestyle changes, there is no conclusive explanation for this rather sudden increase in breast cancer incidence after 1955, which was also noted for skin melanoma and some other cancers. In 2002, it was hypothesized that body-resonant broadcast radiation might act as a threat to the immune system of people who tended to sleep for years in resonance with an FM radio main transmitter [2] If a person sleeps on a metal spring mattress, reflected and standing waves could also explain the fact that the left side of the body in general is more prone to breast cancer [11][12][13][14] and melanoma [1] than the right side of the body. This can be explained by the fact that people tend to sleep for longer times on the right side than on the left side, so that the right side is closer to the field attenuating metal than the left side is [3].…”