NEW YORK (Reuters Health) Women with long-standing hypothyroidism are at increased risk of hepatocellular carcinoma, the results of a case-control study suggest. By contrast, hypothyroidism is not significantly associated with this malignancy in men.

Thyroid hormones are known to be involved in lipid metabolism and fatty acid oxidation and there is evidence linking hypothyroidism with nonalcoholic steatohepatitis, according to the report in the May issue of Hepatology. However, whether thyroid disorders are associated with liver cancer has been unclear.

To answer this question, Dr. Manal M. Hassan, from the University of Texas M. D. Anderson Cancer Center, Houston, and colleagues compared the occurrence and nature of thyroid disease in 420 subjects with hepatocellular carcinoma and in 1104 healthy controls.

After accounting for demographic factors, alcohol use, family history of cancer, and other possible confounders, women with hypothyroidism for longer than 10 years were 2.9-times more likely to develop hepatocellular cancer than their peers without thyroid disease. In the presence of diabetes and chronic hepatitis virus infection, the odds ratios increased to 9.4 and 31.2, respectively.

As noted, hypothyroidism did not affect the risk of liver cancer in men. Hyperthyroidism had no impact on the risk in either sex.

“Further studies among different populations are warranted to confirm the association between hypothyroidism and hepatocellular carcinoma and to identify the underlying biological mechanisms and the genetic predisposition factors that may contribute to susceptibility to hepatocellular carcinoma development in the presence of thyroid disorders,” the authors conclude.

Hepatology 2009;49:1563-1570.