Women, who follow the good habit to get up early in the morning, are less vulnerable to breast cancer risk as compared to those female folk who sleep for longer hours, revealed a study.
The finding has come to fore after researchers analysed databases of more than four lakh women from two studies — UK Biobank study and Breast Cancer Association Consortium (BCAC) study
Using a technique called Mendelian randomisation, they analysed genetic variants associated with three particular sleep traits — morning or evening preference (chronotype), sleep duration, and insomnia.
In observational analysis of UK Biobank data, morning preference was associated with a slightly lower risk of breast cancer (one less woman per 100) than evening preference, whereas there was little evidence for an association with sleep duration and insomnia symptoms.
Analysis from BCAC also supported a protective effect of morning preference, and showed a potential harmful effect of longer sleep duration (more than the recommended 7-8 hours) on breast cancer, whereas evidence for insomnia symptoms was inconsistent.
Eva Schernhammer from the University of Vienna in Austria said these findings, published in the journal BMJ, identify a need for future research exploring how the stresses on our biological clock can be reduced.