Breast cancer. Relationship to thyroid supplements for hypothyroidism.

This study was undertaken to determine the relationship between thyroid supplements and breast cancer. The incidence of breast cancer among the patients who received thyroid supplements was 12.13%, while in the control group it was 6.2%. The incidence rate of breast cancer was 10%, 9.42%, and 19.48% among patients who received thyroid supplements for one to five, 5 to 15, and for more than 15 years, respectively. The incidence of breast cancer among nulliparous women who received thyroid supplements was 33%, while in the nulliparous women without thyroid supplements the incidence was only 9.25%. Even in a specific age group, the incidence rate of breast cancer was higher among patients receiving thyroid supplements, when compared to the control patients in the same age group.