Men who reported sleep disorders or ongoing sleeping problems, including difficulty falling asleep and staying asleep, had up to a twofold increased risk for prostate cancer, according to data published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

Sleep can often be a barometer of your overall health for both men and women. In many cases, people in good health tend to sleep well, whereas those suffering from repeated sleeping might have an underlying medical or mental health problem. An estimated 10% to 15% of the general population report frequent sleep disturbances. These issues are often associated with situational stress, illness or aging.

Increased risk for cancer
“Sleep problems are very common in modern society and can have adverse health consequences,” noted Lara G. Sigurdard?ttir, M.D., at the University of Iceland in Reykjavik. ?Women with sleep disruption have consistently been reported to be at an increased risk for breast cancer, but less is known about the potential role of sleep problems in prostate cancer.?

Previous studies have generated conflicting results for an association between sleep disruption from working night shifts and the risk for prostate cancer. Sigurdard?ttir and her colleagues, therefore, investigated the role of sleep in influencing prostate cancer risk.


The researchers followed 2,102 men from the prospective Age, Gene/Environment Susceptibility-Reykjavik study, called AGES-Reykjavik, which involved an established, population-based cohort of 2,425 men aged 67 to 96. Upon enrollment into the study, the participants answered four questions about sleep disruption: whether they took medications to sleep, had trouble falling asleep, woke up during nights with difficulty going back to sleep or woke up early in the morning with difficulty going back to sleep.[2]

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AGES-Reykjavik was initiated in 2002 and designed to examine risk factors, including genetic susceptibility and gene/environment interaction, in relation to disease and disability in old age. The multidisciplinary study provided detailed phenotypes related to the cardiovascular, neurocognitive (sensory), and musculoskeletal systems, and to body composition and metabolic regulation. Relevant quantitative traits, subclinical indicators of disease, and medical diagnoses were identified using known biomarkers, imaging, and other physiologic indicators.[2]

Among the participants, 8.7% and 5.7% reported severe and very severe sleep problems, respectively. None of the participants had prostate cancer at study entry. The researchers followed the participants for five years, and during this period, 6.4% were diagnosed with prostate cancer.

Risk increased proportionately
After the researchers adjusted for age, they found that compared with men who reported no problems with sleeping, the risk for prostate cancer increased proportionately with reported severity of problems falling and staying asleep, from 1.6-fold to 2.1-fold. Further, the association was stronger for advanced prostate cancer than for overall prostate cancer, with more than a threefold increase in risk for advanced prostate cancer associated with very severe sleep problems.

To rule out the possibility that the problems with sleeping were because of undiagnosed prostate cancer or an enlarged prostate, the researchers reanalyzed the data after excluding men with symptoms of sleep disturbance that might be indicative of nocturia (waking up during the night to urinate). The results remained unchanged.

Further studies
According to Sigurdard?ttir, these data should be confirmed with a larger cohort with longer observation times. ?Prostate cancer is one of the leading public health concerns for men and sleep problems are quite common,? she said. ?If our results are confirmed with further studies, sleep may become a potential target for intervention to reduce the risk for prostate cancer.?

For more information:
[1] Sigurdard?ttir LG, Valdimarsdottir UA, Mucci LA, Fall K, Rider JR, Schernhammer E, Czeisler CA, et al. Sleep Disruption Among Older Men and Risk of Prostate Cancer. Cancer Epidemiol Biomarkers Prev May 2013 22; 872. doi: 10.1158/1055-9965.EPI-12-1227-T [Abstract]
[2] Harris TB, Launer LJ, Eiriksdottir G, Kjartansson O, Jonsson PV, Sigurdsson G, Thorgeirsson G. et al. Age, Gene/Environment Susceptibility ? Reykjavik Study: Multidisciplinary Applied Phenomics. Am J Epidemiol. 2007 May 1; 165(9): 1076?1087. [Full Article]

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