Charity publishes new research dispelling shift work and cancer myth

Working night shifts is not linked to an increased risk of breast cancer, research for a charity has revealed.

For decades, it has been suggested that night shift work may increase a woman’s breast cancer risk, with research concluding in 2007 that shift work disrupting the body’s sleep-wake cycle was probably carcinogenic.

However, new research funded by Breast Cancer Now suggests there may be no impact on breast cancer risk after all.

In a ten-year study of more than 100,000 women researchers examined extensive details of women’s night shift work, finding those who worked night shifts were no more likely to develop breast cancer than those who had not.

Breast cancer is the UK’s most common cancer, with around 55,000 women and 350 men being diagnosed each year.

Delyth Morgan, chief executive at Breast Cancer Care and Breast Cancer Now, said: “We hope these findings will help reassure the hundreds of thousands of women working night shifts that it’s unlikely their job patterns are increasing their risk of breast cancer.

“This question has been widely debated in recent decades and has understandably caused concern, and it’s encouraging that the evidence now suggests night shift work has no impact on breast cancer risk.”

Previously it was suspected that shift work and an increased breast cancer risk could be explained by exposure to light at night disrupting the body’s internal clock, which could cause suppression of the sleep hormone melatonin and raise oestrogen levels in the body.