Alison Mondul

-

NCI

-

PLCO (Learn more about this study)

2012-0027

Apr 27, 2012

Thyroid Hormones, Thyroid Status, and Risk of Prostate Cancer

Despite laboratory evidence that thyroid hormones may be pro-carcinogenic, few observational studies have examined the relationship between thyroid hormone concentrations and risk of prostate cancer. Our research group recently conducted an analysis that found men whose thyroid hormone levels indicated they were clinically or sub-clinically hypothyroid were at a significantly decreased risk of prostate cancer compared to euthyroid men (OR=0.48, 95% CI=0.28-0.81, p=0.006). This finding supported the one previous study of the hypothesis which similarly found men who were hyperthyroid were at a two-fold increased risk of prostate cancer. These associations are quite striking and warrant replication in a larger sample size where hypo- and hyperthyroid states can be prospectively examined simultaneously in one cohort. We propose to examine the association between serum thyroxine (T4), thyroid-stimulating hormone (TSH), and thyroid binding globulin (TBG), as well as calculated free T4 and risk of prostate cancer in the PLCO cohort. Further, we will use the laboratory measured thyroid hormone levels to categorize men as being in a hypothyroid, euthyroid, or hyperthyroid state, based on recent endocrinological guidelines. We will then examine the association between a hypo- or hyperthyroid state and risk of prostate cancer. Understanding the associations between thyroid hormones, thyroid status, and risk of prostate cancer will contribute to our understanding of prostate cancer etiology, and may have implications for the clinical management of thyroid status.