Regularly getting too little sleep could increase the risk of aggressive breast cancer, according to a new study.
Getting six or fewer hours of sleep each night seemed to increase the risk of cancer recurring among post-menopausal breast cancer patients, found researchers from the University Hospitals Case Medical Center’s Seidman Cancer Center and the Case Comprehensive Cancer Center at Case Western Reserve University.
"Effective intervention to increase duration of sleep and improve quality of sleep could be an under-appreciated avenue for reducing the risk of developing more aggressive breast cancers and recurrence," study researcher Dr. Li Li, M.D., Ph.D., said in a statement.
The study, published in the journal Breast Cancer Research and Treatment, included 412 breast cancer patients who were all post-menopausal. They were all tested with Oncotype DX, which is a tool doctors use to predict whether cancer will recur. They were also surveyed about their sleep habits for the past two years.
The researchers found an association between a higher score on the Oncotype DX test and decreased sleep.
The findings suggest "that lack of sufficient sleep may cause more aggressive tumors, but more research will need to be done to verify this finding and understand the causes of this association," study researcher Cheryl Thompson, Ph.D. said in the statement.
However, researchers said they didn't find a link between aggressive breast cancer and pre-menopausal breast cancer patients, which suggests that cancers among pre-menopausal women and post-menopausal women may work differently.
Recently, a study presented at the American Thoracic Society 2012 International Conference also suggested a link between sleep problems and cancer risk. That research, conducted by scientists at the University of Wisconsin School of Medicine and Public Health, showed a link between severe sleep-disordered breathing -- seen in obstructive sleep apnea -- and a five times increased risk of dying from cancer, compared with people without the sleep condition.