Lack of sleep linked to breast cancer

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Women who regularly sleep for 6 hours or less a night are at higher risk of getting breast cancer, according to new research.

The study in Japan tracked nearly 24,000 women over 8 years and discovered that those who got by on 6 hours or less sleep a night were 62% more likely to have breast cancer compared with those sleeping 7 hours.

During the study, 143 women were diagnosed with breast cancer.

Scientists believe disrupted sleep interferes with the production of a hormone called melatonin which protects against cancer.

Melatonin is believed to help regulate the body's internal clock and keep down the amount of oestrogen released. The development of a large number of breast cancer cases is known to be down to oestrogen levels.

Prostate cancer risk

The same study also reported that men with 9 hours' sleep a night cut their risk of prostate cancer in half, compared with those who slept less.

Cancer Research UK said that a 'growing number of studies' had noticed a link between lack of sleep and cancer.

But a professor in sleep medicine at Loughborough University, Jim Horne, criticised the study, saying: 'Most women have nothing to worry about and there is no good evidence that sleeping for longer helps to prevent breast cancer.'