Unhealthy Sleep Patterns May Be Linked to Higher Breast Cancer Risk - Study

Staying up late and maintaining unhealthy sleep patterns may be associated with a higher risk of breast cancer, according to a study published in BMC Cancer. Researchers analysed sleep patterns and breast cancer risk among 159,452 women from the UK Biobank. During the follow-up period, 7,291 participants developed breast cancer. After accounting for demographic and lifestyle factors, women with unhealthy sleep patterns were found to have a 10% higher breast cancer risk than those with healthier sleep patterns. Researchers also identified biological signals involving immune regulation and inflammation, suggesting that disrupted sleep and circadian rhythms could influence processes involved in the body’s cancer defence.

The body’s circadian rhythm acts as an internal 24-hour clock that regulates sleep, hormone release and immune activity. Repeated disruption of the normal light-dark cycle may affect immune surveillance, while exposure to light at night can suppress melatonin and delay sleep. Late-night phone use, television viewing and bright indoor lighting may therefore contribute to sleep disruption. However, the study did not directly measure artificial light exposure at night and cannot establish that staying up late or using a phone causes breast cancer. Researchers also found that genetic susceptibility could influence the risk, with the highest risk observed among women who had both higher genetic risk and unhealthy sleep patterns. The findings do not suggest that occasional late nights cause cancer, but highlight the importance of maintaining regular and healthy sleep patterns over time.