Insomnia can double the risk of prostate cancer in older men, a study suggests. The risk rises proportionately with the severity of sleep problems, increasing from 1.6 to 2.1 times the usual level.
The reason is not known. But a link has also been seen between insomnia and breast cancer in women.
"Sleep problems are very common in modern society and can have adverse health consequences," said the study leader Dr Lara Sigurdardottir, from the University of Iceland in Reykjavik. She presented the report at the Genito-urinary Cancers Symposium in San Francisco. "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."
More than 2,000 men aged 67 to 96 were questioned about their sleeping habits. They were asked if they took sleeping pills, had trouble falling asleep, found it difficult to get back to sleep after waking in the night, or woke early and stayed awake.
The project showed 6.4 per cent of the men were diagnosed with prostate cancer during its five-year period. Compared with men who had no problems sleeping, those suffering from insomnia were significantly more likely to develop prostate cancer.