Thyroid hormone levels can be measured in the blood by a simple lab test. Thyroxine (T4) is the major hormone produced by the thyroid gland and it can be measured as free T4 in the blood. There have been studies suggesting that higher levels of free T4 in the blood may be associated with an increased risk of developing a solid cancers (for example, lung, breast, prostate, gastrointestinal (GI) cancers). Other studies have not agreed with this finding. This study looks at a large group of people to determine whether T4, even within the normal range, may increase the risk of developing any solid cancer.
THE FULL ARTICLE TITLE:
Khan SR et al. Thyroid function and cancer risk: the Rotterdam Study. J Clin Endocrinol Metab. September 20, 2016 [Epub ahead of print].
SUMMARY OF THE STUDY
The study included a group of middle to older aged subjects from the Rotterdam Study in the Netherlands which investigated a variety of medical conditions in older people. Using this population, the authors were able to include 10,318 participants who all had thyroid hormone blood tests (TSH, FT4), who did not have a history of cancer, and who they could follow from 1990 to 2012 or death to determine if the subject developed a solid cancer.