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A GOOD night鈥檚 sleep may not only keep you beautiful, it could also protect
you from cancer.

Two separate studies have found an association between working night shifts
and an increased risk of developing breast cancer. One, from the Fred Hutchinson
Research Center in Seattle, reports that working at night, or sleeping in a
brightly lit bedroom, increases the risk of breast cancer by up to 60 per cent.
Another, from Brigham and Women鈥檚 Hospital in Boston, shows that the risk
increased by 36 per cent for nurses who鈥檝e been working night shifts for more
than 30 years.

Those might sound like frightening figures, but Eva Schernhammer, a member of
the Boston team, says the risk is actually low. 鈥淔or a 50-year-old woman in
America, what we found may translate to maybe one or two added cancer cases per
100,000,鈥� she says.

The take-home message from both studies is the same, says Eva Singletary of
the MD Anderson Cancer Center in Houston. 鈥淚 don鈥檛 think a woman should be
overly alarmed,鈥� she says. 鈥淭hat said, there are things a woman could do if
concerned,鈥� she says, like interrupting night shifts for periods of time.

The reasons for the increased risk are still unclear, but both teams think it
involves melatonin, a hormone whose levels peak at night. In people exposed to
light at night, melatonin levels stay low. Less melatonin could mean more
oestrogen is produced, which would affect breast growth. Alternatively,
melatonin might directly affect the development of tumours.