You might feel tired if you don't sleep well, but the good news is that women who are poor sleepers are no more likely to be diagnosed with breast cancer than sleeping beauties, according to a Western Australian study published in the United States.
There is evidence to suggest that people may be getting between 13 and 36 minutes less sleep per night than they were in the 1980s. Some international studies have suggested that a reduction in the number of hours and quality of sleep in modern times might be causing an increase in breast cancer cases. However, recent research from WA does not support this claim.
"It's nice to be able to reassure women who don't sleep well because they're waking in the night to children, doing shift work, or simply burning the candle at both ends, that their sleeping habits have no association with breast cancer," said one of the authors, Jennifer Girschik.
"A lot of previous studies, conducted overseas, have reported an association between lack of sleep and breast cancer, but these were studies that only asked a single question about sleep duration, while our study looked at a number of aspects of sleep duration and sleep quality as well as a combination of the two," Ms Girschik said.
The study, "Self-reported Sleep Duration, Sleep Quality, and Breast Cancer Risk in a Population-based Case-Control Study" was carried out by Perkin's Epidemiology Group, headed by Professor Lin Fritschi. It has been published online in the American Journal of Epidemiology.
The researchers investigated the relationship between breast cancer, sleep duration and sleep quality in Western Australian women aged between 18 and 80, obtaining data from a population-based case-control study conducted from 2009 to 2011.
Participants were female patients with a first incident invasive breast cancer reported to the Western Australian Cancer Registry and a control group who were randomly selected from the electoral roll. They were matched to the expected distribution of breast cancer cases by 5-year age group.
The women completed a postal questionnaire that included questions on how well they slept as well as questions about their demographic, reproductive and lifestyle factors.