In a previous study, cancer risks associated with the person's body clock and sleep patterns were reported, and UK researchers wanted to investigate the sleep characteristics in more detail and investigate the underlying genetic factors.
Self-reported preferences for mornings or evenings Dr. More than 180,000 women led by Rebecca Richmond, the UK, worked as a research assistant at the UK Integrative Cancer Epidemiology Program of Cancer Research and Epidemiology Unit at the University of Bristol and presented on Tuesday at the NCRI Cancer Conference in Glasgow. .
Richmond's team also analyzed genetic variants linked to whether someone was in the morning or in the night. More than 220,000 women to find out if they can help provide a causal link to breast cancer.
This type of statistical model, called Mendelian randomization, has shown that people with a higher probability of early promoters to develop breast cancer are less likely to develop breast cancer. As seen in the study 220,000 participants, up to 48%.
The second analysis showed a similar trend in early-onset women with a 40% lower breast cancer risk by using the self-reported data from sleep at 180,000 participants. Variation stems from technical differences, Richmond.
According to his team's Mendelian randomization analysis, women who reported self-reported sleep more than seven to eight hours per night, had a slightly higher risk of breast cancer and had slept 20% per hour.
However, the team indicates that many factors are involved in a person who has breast cancer and these numbers are not an absolute risk. Moreover, the findings do not apply across the population as the majority of women are European ancestors.
"Sleep is a major risk factor for breast cancer, but it is not as big as other well-known risk factors like BMI or alcohol," said Richmond.
”We know sleep is important for health, Richmond said Richmond. "These findings have potential policy effects to influence the sleep patterns of the general population to improve health and reduce the risk of breast cancer among women."
Our circadian rhythms or body clocks control bodily functions such as sleep patterns, blood pressure and metabolism, and can increase the risk of cancers and other diseases when disturbed.
Richmond's team carried out their genetic analysis in the hope of digging on the possible causes and consequences of this connection. However, experts warn that more research is needed and current findings cannot be applied on a wider scale.
"The statistical method called Mendelian randomization used in this study does not always allow the emergence of causality," said Dipender Gill, a specialist in clinical research training at Imperial College London. "For example, genetic determinants of sleep may also affect other neuronal mechanisms that affect breast cancer risk independent of sleep patterns. In such a scenario, sleep patterns may be related to breast cancer risk, but not directly."
Stephen Burgess, a postdoctoral fellow at Cambridge University, added that a mechanism for explaining the connection was not known or understood.
"The authors do not show any biological mechanism in which the preference for sleep timing may affect the risk of breast cancer. Another limitation is that the chronotype is reported on its own and that the research does not specifically take individuals with different sleep patterns. Night shift workers," Burgess wrote in the comments of the study.
The study has not yet been published in a medical journal. Gill added that peers have not yet been evaluated by other experts in the field.
Not as big as other factors
Richmond emphasized that a lower risk of 48% is defined as "extreme" cases, that people define themselves as a "definite" morning community from the five categories in which they can choose themselves – more in the morning, in the morning than in the morning, in the evening, in the morning .
”Sleep is an important risk factor for breast cancer,“ he said. However, weight and alcohol consumption are not as great as a risk factor, as well as other well-known, Richmond added.
Richmond said night birds shouldn't worry about the findings. "I don't support women should get up early to reduce the risk of breast cancer."
There are theories around the causes of the effects of sleep on cancer, such as the idea that artificial light causes hormonal deterioration at night.
The senior policy analyst in the epidemiology of the PHG Foundation, which was not involved in the research. Sowmiya Moorthie added that the great power of the study was the use of multiple approaches to study the relationship between sleep characteristics and breast cancer. to show consistency in their findings.
"For the results of the study, it supports existing evidence that sleep patterns affect cancer risk, but it remains unclear how individual preferences interact with actual sleep behaviors for early or late promotion," Moorthie said.