A study conducted in France among 1,232 women diagnosed with breast cancer between 2005 and 2007 show that working at night exposes women to breast cancer.
A study published in the International Journal of Cancer, the INSERM-led team said an association between night work with breast cancer “was mainly observed in women working during overnight shifts, those who worked at night for 4.5 or more years and less than three nights per week on average.
“The association was stronger in women who worked at night before their first full-term pregnancy than in women who started working at night later in life.”
The scientists said more study was needed to determine the reasons.
Hypotheses include disruption of “body clock” genes, internal desynchronisation and sleep deprivation altering the immune system.