Working night shifts is unlikely to increase the risk of breast cancer, British researchers have claimed, clarifying a previous study on the effect of night shifts on women.

The new research, funded by the British Health and Safety Executive (HSE), Cancer Research U.K. and the U.K. Medical Research Council, was published in the Journal of the National Cancer Institute. It followed 1.4 million women in ten studies and analyzed data from studies in the United States, China, Sweden and the Netherlands.

“We found that women who had worked night shifts, including long-term night shifts, were not more likely to develop breast cancer,” Ruth Travis, lead author and cancer scientist at the Cancer Epidemiology Unit at the University of Oxford, told Xinhua.  Professor Andrew Curran, chief scientific adviser for the HSE, however, warned that there are a number of other known risks with working night shifts.
A study by the International Agency for Research on Cancer in 2007 had said that working night shifts is a probable cause of cancer, including breast cancer, as it disrupts an individual’s ‘body clock.’ Referring to new updated research, scientists now say that the 2007 review was mainly based on studies of animals and lab records.