Mammary Gland Dysplasia in Iodine Deficiency

Abstract

Epidemiological studies suggest that persons living in areas of normal iodine availability show less breast cancer than those living in iodine-deficient areas.^1,2World Health Organization investigations, recently published,³have revealed that a large segment of the population in the United States and other parts of the world lives in areas of limited iodine availability. In addition, there appears to be statistical evidence of an increased incidence of breast malignancy in hypothyroidism.^4-6Our results imply that iodine deficiency may be involved in these thyroid-breast relationships. The breasts of chronically iodine-deficient female rats treated with testosterone were observed to be considerably larger than their normally fed, testosterone-injected litter-mate controls. No reports directly pertaining to this observation were found in the literature. Therefore, we decided to carry out a systematic investigation of the influence of iodine deficiency on the resting and sex-hormone-treated breasts of female rats. The changes seen were