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Colorectal cancer incidence tied to TSH levels
The incidence of colorectal cancer may be increased in older men with elevated thyroid-stimulating hormone levels, study data show.
Bu B. Yeap, PhD, MBBS, FRACP, professor in the school of medicine and pharmacology at the University of Western Australia in Perth, and colleagues evaluated data from 3,836 men (mean age, 77 years) living in Perth between 2001 and 2004 whose thyroid hormone levels were recorded to determine the relationships between TSH and free thyroxine with cancer incidence, including all cancers, prostate, colorectal and lung cancer. Participants were followed by electronic linkage until June 20, 2013.
Compared with participants who did not develop cancer, participants who developed colorectal cancer had higher TSH levels, and participants who developed lung cancer had higher free T4 levels.
During a median follow-up of 9 years, 864 participants were diagnosed with cancer; 340 with prostate, 136 with colorectal and 119 with lung cancer. The incidence of all cancers or prostate cancer was not associated with TSH. The increased incidence of colorectal cancer was tied to higher log TSH in the fully adjusted analysis (P = .048), and the relationship remained significant after the first year of follow-up was excluded (P = .028). In the univariate analysis, log TSH was inversely related to lung cancer incidence (P = .02); however, this was no longer significant in the fully adjusted analysis. An association was also found between higher free T4 and a higher incidence of lung cancer (P = .014); however, this did not remain significant after adjustments.
Cancer-related deaths were not associated with log TSH or free T4 in the fully adjusted analysis.
“In older men, higher TSH is associated with incidence of colorectal cancer,” Yeap told Endocrine Today. “Further research is needed to determine whether higher TSH is a marker for or might contribute to the risk of colorectal cancer.” – by Amber Cox
For more information:
Bu B. Yeap, PhD, MBBS, FRACP, can be reached at bu.yeap@uwa.edu.au.
Disclosure: The researchers report no relevant financial disclosures.