Underactive Thyroid Increases Risk of Coronary Heart Disease

Like people who have hypothyroidism, those who have no symptoms of an underactive thyroid also have an increased risk of coronary heart disease. In a recent meta study combining the results of 14 observational studies, researchers at the University of Lausanne, Switzerland found:

• Subjects with an underactive thyroid without symptoms, also referred to as subclinical hypothyroidism, had a 65 percent increased risk of coronary heart disease.
• Nine studies included a comparison group without hypothyroidism, matched to the hypothyroid group for age and demographic factors — those with subclinical hypothyroidism had an increased risk of 81 percent for heart disease.
• In studies that accounted for the potential influence of the presence of cardiovascular risk factors, the heart disease risk in subjects with subclinical hypothyroidism was more than doubled.

Hypothyroidism can cause a number of various complications including higher levels of LDL cholesterol and heart abnormalities. Despite this, the study concludes that not enough evidence exists to promote the screening of asymptomatic adults for thyroid function.

Dr. Nicolas Rodondi:

Before recommending screening, clinical trials are needed to assess whether thyroxine treatment reduces the risk of coronary heart disease in subjects with subclinical hypothyroidism.

Reuters, July 28, 2006