A new scientific study suggests that early-risers are less likely to develop breast cancer than others. We detail its main results.
This is probably a study that will delight young parents who get up early every morning! According to a very serious study presented at a conference of the British Cancer Institute (NCRI) in Glasgow, women who are in the morning would have a 40% reduced risk of breast cancer compared to women in the evening, who get up late.
Led by researchers at the University of Bristol, the study suggests that our internal clock, or circadian rhythm, may play a role in our likelihood of having breast cancer. Note that this circadian rhythm, which follows a cycle of about 24 hours, is specific to everyone and varies throughout life: for example, children are more likely to get up early than teenagers, and so on.
Here, the research team used a method called "Mendelian Randomization" to carry out this work: it involves identifying and using genetic variants related to potential risk factors, here the circadian rhythm, to determine whether or not there is a correlation between the latter and a disease, here breast cancer. This method is considered more reliable than other observation methods.
The study was based on data from 180,215 women enrolled in the British Biobank project and 228,951 women who participated in a global-genome breast cancer association study conducted by the international consortium BCAC (Breast Cancer Association Consortium). In all, 314 circadian rhythm variants were analyzed.
"Early bird" women better off than "night owls" for breast cancer
Verdict: The risk of breast cancer was 40% lower in patients with "early bird" genetic variants than in more evening females in BCAC data. Each additional hour of sleep beyond the recommended 8 hours was also associated with a 20% increase in breast cancer risk.
The data showed that over an eight-year period, about two in every 100 "late-onset" women will be diagnosed with breast cancer, compared with only one "early bird" woman out of 100.
"We would like to continue our work to study the mechanisms underlying these results, since the estimates obtained are based on questions related to morning or evening preferences, and not to the question of whether people get up earlier or later in the day. In other words, changing your habits may not change your risk of breast cancer, it can be more complex than that, "said Rebecca Richmond, lead author of the study.
"However, the results of our study on the protective effect of morning preference on breast cancer risk are in line with previous research highlighting the role played by night work and exposure to 'night light' as risk factors for breast cancer, "concluded the researcher.
Source: University of Bristol