by Dr. Eowyn
HealthDay News reports (via MedicineNet) that a new study found that women who are early risers are less likely to develop breast cancer.
British researchers analyzed two data banks on more than 409,000 women and found that:
- Compared to night owls, women who are early risers had a 40% lower risk of breast cancer.
- Women who slept longer than the recommended 7 to 8 hours a night had a 20% increased risk of breast cancer for each additional hour slept.
The study was presented on November 6, 2018, at the U.K.’s National Cancer Research Institute (NCRI) annual cancer conference, in Glasgow, Scotland. Research presented at meetings is considered preliminary until published in a peer-reviewed journal.
Rebecca Richmond, a research fellow in the Cancer Research U.K. Integrative Cancer Epidemiology Program at the University of Bristol, said:
“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. 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…. We also found some evidence for a causal effect of increased sleep duration and sleep fragmentation on breast cancer.”
Although this discovery of a correlation between early riser and breast cancer does not establish a causal connection, there is enough data on the deleterious health effects of people who work night shifts to suggest causation.
Cliona Clare Kirwan, a member of the NCRI Breast Clinical Studies Group who was not involved in the UK research, said:
“These are interesting findings that provide further evidence of how our body clock and our natural sleep preference is implicated in the onset of breast cancer. We know already that night shift work is associated with worse mental and physical health. This study provides further evidence to suggest disrupted sleep patterns may have a role in cancer development.”