New UK research presented at the 2018 NCRI Cancer Conference suggests that women who are “larks”, performing better at the beginning of the day rather than the end of the day, may have a lower risk of breast cancer.
Led by Dr. Rebecca Richmond at the University of Bristol, UK, along with the University of Manchester, the University of Exeter, and US and Norwegian researchers, the large-scale study looked at data from taken from 409,166 women to investigate how a person’s preference for mornings or evenings as well as their sleep habits may contribute to the development of breast cancer.
The participants included 180,215 women enrolled with the UK Biobank project – a large long-term study which includes genomic data on about half a million people – and 228,951 women who had been part of a study on breast cancer carried out by the international Breast Cancer Association Consortium (BCAC), which has the largest collection of genetic data on women with breast cancer in the world.
The team used a method called Mendelian randomisation, which uses genetic variants associated with possible risk factors for breast cancer, such as sleep characteristics, to see whether they are involved in causing disease. This type of analysis gives more reliable results, so if an association is found it is more likely to suggest a direct relationship.
The data from the BCAC group of participants showed that women who were morning types, also known as “larks,” had a 40% reduced risk of breast cancer compared with those who were evening types, or “owls”.