Low thyroid output tied to heart attacks in women

NEW YORK (Reuters Health) - Women with a slightly underactive thyroid gland appear to be at increased risk for death from heart attacks and other types of heart disease, according to findings from a Norwegian study reported in the Archives of Internal Medicine.

Emerging evidence suggests that as thyroid function drops, blood pressure and cholesterol levels rise as does the risk of heart problems, note Dr. Bjorn O. Asvold at Trondheim University Hospital and colleagues.

Asvold's group investigated the association in a study of 17,311 female and 8002 male participants in the Nord-Trondelag Health Study who were free of heart disease, thyroid disease, and diabetes when the study began. Subjects were over 40 years old between 1995 and 1997, when levels of thyrotropin, a hormone that gauges thyroid function, were measured.

During follow-up through 2004, 192 women and 164 men died of heart disease who appeared to have normal thyroid function. That is, none of the patients had any signs or symptoms of an underactive or overactive thyroid gland.

Among subjects with seemingly normal thyroid function, women with the least active glands were 69 percent more likely to die from heart disease than women with more active glands.

No similar association was seen in men.

"To our knowledge, no clinical trial has tested whether (treatment with thyroid hormone) could protect against heart disease," the authors note. However, there is evidence that such treatment can reduce high blood pressure, cholesterol levels, and body weight, they add.

SOURCE: Archives of Internal Medicine, April 28, 2008.