Morning People '40% Less Likely To Develop Breast Cancer' Than Night Owls

But changing your habits might not change your risk.

Women who are “larks” and at their best early in the morning are less likely to develop breast cancer than those who are night owls, according to a new study.

Researchers from the University of Bristol compared data on more than 400,000 women and found those who classed themselves as “morning people” were 40 - 48 per cent less likely to be diagnosed with breast cancer than others. The research also suggested that for women who slept longer than the recommended seven to eight hours per night, the risk of being diagnosed increased by 20 per cent per additional hour slept.

“We would like to do further work to investigate the mechanisms underpinning these results, as the estimates obtained are based on questions related to morning or evening preference rather than actually whether people get up earlier or later in the day,” said lead scientist Dr Rebecca Richmond, from the University of Bristol.

Dr Richmond continued: “In other words, it may not be the case that changing your habits changes your risk of breast cancer, it may be more complex than that.

“However, the findings of a protective effect of morning preference on breast cancer risk in our study are consistent with previous research highlighting a role for night shift work and exposure to ‘light-at-night’ as risk factors for breast cancer.”

The findings were presented at the 2018 NCRI (National Cancer Research Institute) conference in Glasgow.

However Dr Richard Berks, senior research communications officer at the charity Breast Cancer Now, said it’s too early to make any recommendations to women about their sleeping patterns based on this research.

“These intriguing results add to the growing body of evidence that there is some overlap between the genetics of when we’d prefer to sleep and our breast cancer risk, but more research is required to unravel the specifics of this relationship,” he said.

“What we can be certain of is that all women – larks and owls – can reduce their risk of breast cancer by exercising regularly, maintaining a healthy weight and reducing their alcohol intake.”