Study: Women who love a lie-in have a higher risk of developing breast cancer

Women who love a lie-in have a higher risk of developing breast cancer, a new study has warned.

Researchers from the University of Bristol have analysed the link between sleeping patterns and breast cancer in women.

Their findings suggest that ‘larks’ - women who function better at the beginning of the day than the end - have a lower risk of developing breast cancer than those who love to lie-in.

In the study, the researchers looked at data from 409,166 women - some who have had breast cancer, and some without the disease.

Dr Rebecca Richmond, who led the study, said: “Using genetic variants associated with people's preference for morning or evening, sleep duration and insomnia, which had previously been identified by three recent UK Biobank genome-wide association studies, we investigated whether these sleep traits have a causal contribution to the risk of developing breast cancer.

Their analysis revealed that women with a preference for mornings reduced the risk of breast cancer by 40%, compared with being an evening type.

It also found that women who slept longer than seven to eight hours a night had a 20 percent increased risk of the disease per additional hour slept.

Dr Richmond said: "These findings have potential policy implications for influencing sleep habits of the general population in order to improve health and reduce risk of breast cancer among women.”

The team now plans to investigate the mechanisms underlying the effects further.

Dr Richmond added: “We would like to use genetic data from large populations to further understand how disrupting the body's natural body clock can contribute to breast cancer risk.”