Researchers have warned that the women who work night shifts are at a higher risk of breast cancer.
According to a report published in the Daily Mail, working at night increases the chances of the disease by 40 per cent.
The reports suggest that the women working more than two night shifts a week have double the risk of those on day shifts.
The Daily Mail report states that a hormone in the body that potentially suppresses tumours may be disrupted by constant exposure to light during night-time hours.
The night shift work was linked with a 40 per cent increased risk of breast cancer compared with no night shifts. But women who had worked night shifts at least three times a week for at least six years were more than twice as likely to have contracted the disease as those who had not.
Those working this shift pattern for this length of time were even more likely to develop breast cancer if they were ‘morning’ types, says a report in the journal Occupational and Environmental Medicine, the report said.
Exposure to light at night inhibits production of melatonin, which is produced by the pineal gland in the brain between the hours of 9pm and 8am. Melatonin, a hormone which dictates the natural cycles that govern sleep patterns, helps suppress tumours.
Research suggests that unusually low levels of melatonin, which are seen in people exposed to light during the night, may promote tumour growth.