Researchers at the University of Bristol, founds a causal link between sleeping for longer and breast cancer.
A study on several women, which was investigating whether the way people sleep, can contribute to the development of breast cancer, also found some evidence for a causal link between sleeping for longer and breast cancer. The research was presented at the 2018 NCRI Cancer Conference.
Researchers found that a preference for mornings reduced the risk of breast cancer by 40 to 48 percent compared with being an evening type (an ‘owl’). It also found that women who slept longer than the recommended seven to eight hours had a 20 percent increased risk of the disease per additional hour slept.
Dr Rebecca Richmond of the University of Bristol , who lead the research team said “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,” .
“We also found some evidence for a causal effect of increased sleep duration and sleep fragmentation on breast cancer, assessed using objective measurements of sleep obtained from movement monitors worn by participants,” she added.
The researchers believe their findings have implications for policy-makers and employers. Dr Richmond said: “These findings have potential policy implications for influencing sleep habits of the general population in order to improve health and reduce the risk of breast cancer among women.”