liveonearth (liveonearth) wrote,

More Sleep-->Less Cancer (Prostate, Breast)

2 studies using data from the Ohsaki Cohort support this correlation

Ohsaki Cohort
large Japanese study started in 1994
The Ohsaki National Health Insurance Cohort Study
population-based, prospective cohort study
n = 40,530 Japanese adults aged 40 to 79 years w/o hx of stroke, coronary heart dz or CA
pts followed for up to 11 years (1995-2005) for all-cause mortality
and followed for up to 7 years (1995-2001) for cause-specific mortality

one study from this data that's not about sleep
Kuriyama S, Shimazu T, Ohmori K, Kikuchi N, Nakaya N, Nishino Y, Tsubono Y, Tsuji I. Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study. JAMA. 2006 Sep 13;296(10):1255-65.

Kakizaki looked at sleep and cancer from same data
two papers published in 2008 in the British Journal of Cancer
papers: one on prostate cancer and one on breast cancer risk (vs sleep)
both studies find that inadequate sleep-->increased cancer risk
prostate study published July 2008
there were 3 prior studies linking sleep duration with breast cancer risk
theory: melatonin from pineal gland is cancer preventative
melatonin from pineal-->GNRH from anterior pituitary-->synthesis and secretion of sex hormones
melatonin theory supported by observational studies
that show night work, shift work and visual impairment incr risk of sex-hormone-related CA
ie breast and prostate CA
there are studies on increased risk caused by outdoor lighting at night

Of 22,320 Ohsaki men, 127 developed prostate cancer
9 hour was cutoff: correlation with sleeping this long and getting less prostate cancer
not many people in the US today get 9 hours sleep a night, but like to if I can
Kakizaki M, Inoue K, Kuriyama S, Sone T, Matsuda-Ohmori K, Nakaya N, Fukudo S, Tsuji I; Ohsaki Cohort Study. Sleep duration and the risk of prostate cancer: the Ohsaki Cohort Study. Br J Cancer. 2008 Jul 8;99(1):176-8. Epub 2008 Jun 10.

Of 23,995 women, 143 developed breast cancer
divided along lines of 7+ hours a day, or six or less
stronger correlation than with the men for less sleep-->more cancer
women who sleep 6 hours are 1.5x more likely to get breast CA than those who sleep 7 hours
women sleeping 9+ hrs/nt get ~25% less CA than the 7 hour sleepers
Kakizaki M, Kuriyama S, Sone T, Ohmori-Matsuda K, Hozawa A, Nakaya N, Fukudo S, Tsuji I. Sleep duration and the risk of breast cancer: the Ohsaki Cohort Study. Br J Cancer. 2008 Nov 4;99(9):1502-5.

Jacob Schor Articles Articles on Melatonin:
and breast cancer:
light at night and breast cancer:
and blue light:

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Tags: breast, cancer, hormones, melatonin, prostate, sleep, tea, women

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