Hyperthyroidism increases risk of breast cancer

Hyperthyroidism increases risk of breast cancerA link has been found between overactive thyroid and breast cancer whereby women who have hyperthyroidism have been found to have an increased risk of breast cancer. According to researchers, the risk is 11 percent higher, compared to women with normal functioning thyroids.

Although hyperthyroidism was associated with an increased risk of breast cancer, hypothyroidism – an underactive thyroid – was found to decrease the risk of breast cancer by six percent.


The findings come from a 36-year review that identified nearly 80,000 Danish women with hyperthyroidism and over 61,000 women with hypothyroidism. All the women were cancer free at the beginning of the study.

Lead author Dr. Jens Otto Lunde Jorgensen said, “Women with thyroid disease are more likely to see their doctor and to undergo examinations, including mammography. Women with overactive thyroid disease also are predisposed to other diseases, such as breast cancer, but it is not the overactive thyroid by itself. Thyroid hormones may contribute to development of breast cancer. [And] treatment of overactive thyroid disease increases the risk of breast cancer. These are all possibilities, but the bottom line is that we do not know for sure.”
Although the findings reveal an association between the two conditions, they do not reveal cause and effect, and Dr. Jorgensen does not believe that doctors need to increase the screening for thyroid disorders as a means to lower breast cancer risk.

The findings were published in the European Journal of Endocrinology.

Also read: Grave’s disease, increased risk of hyperthyroidism and goiters


Author Bio

Devon Andre has been involved in the health and dietary supplement industry for a number of years. Devon has written extensively for Bel Marra Health. He has a Bachelor of Forensic Science from the University of Windsor, and went on to complete a Juris Doctor from the University of Pittsburgh. Devon is keenly aware of trends and new developments in the area of health and wellness. He embraces an active lifestyle combining diet, exercise and healthy choices. By working to inform readers of the options available to them, he hopes to improve their health and quality of life.