A new study has found that working night shifts had little to no effect on the risks of breast cancer.
This research follows a review by International Agency for Research on Cancer (IARC) in 2007, which suggested that the probable cause of cancer might be the disrupted body clock caused by shift work.
The new research analysed data of 1.4 million women to determine whether night shift work increased women’s breast cancer risk.
The researchers made comparisons between women who had never worked night shifts, those who have and others who had worked night shifts for over 20 years.
Lead author Dr Ruth Travis, said: “We found that women who had worked night shifts, including long-term night shifts, were not more likely to develop breast cancer.”
The results showed that the occurrence of breast cancer was the same whether someone did no night shift work at all or did night shift work for several decades.
According to Huffington Post, the combined relative risks were 0.99 for any night shift work, 1.01 for 20 or more years of night shift work, and 1.00 for 30 or more years night shift work.
Chief scientific adviser for the Health and Safety Executive (HSE), which commissioned the study Professor Andrew Curran, said: “Breast cancer is the most common cancer in women so it was vital for us to fund work in this area to establish if there is a link to night work.”
“However, there are a number of other known risks with shift work that employers must take into consideration when protecting their workers’ health and safety.”
Cancer Research UK’s health information manager, Sarah Williams said: “Research over the past years suggesting there was a link has made big headlines, and we hope that today’s news reassures women who work night shifts.”
“Women can reduce their risk of breast cancer by keeping a healthy weight, drinking less alcohol and being active,” Williams concluded.