Thyroid problems linked to risk of sudden cardiac death

Story highlights

  • Higher-than-normal thyroid hormone levels might raise risk of sudden cardiac death
  • Thyroid hormones can offer benefits to treat heart disease if the right dose is given, experts say

(CNN)You owe a lot to your thyroid.

The small butterfly-shaped gland in your neck produces the hormones thyroxine and triiodothyronine, which help control many activities in your body, from how quickly you burn calories to how fast your heart beats.
    However, when the gland is underactive (a condition called hypothyroidism, associated with too little thyroxine) or overactive (a condition called hyperthyroidism, associated with too much thyroxine), it can wreak havoc on your body.
      Scientists have long known that thyroid problems that stem from an imbalance of its hormones may be associated with subsequent heart problems, from an irregular heartbeat to cardiovascular disease.
      Now, they've added sudden cardiac death to that list of potential heart problem connections, according to a new study published in the journal Circulation on Tuesday.
      "Our study suggests that persons with higher thyroid hormone levels, even within what we consider the normal range of thyroid function, have a four-fold increased risk of sudden cardiac death compared to persons with lower thyroid hormone levels," said Dr. Layal Chaker, research fellow in endocrinology and epidemiology at Erasmus University Medical Center Rotterdam in the Netherlands, lead author of the study.
      "The risk factors that were known for sudden cardiac death were mainly the 'traditional' cardiovascular risk factors, including high cholesterol and high blood pressure. However, it was not known that higher thyroid hormone levels could also be a risk factor for sudden cardiac death," she added. "Our study shows that thyroid function at the high end of normal is a risk factor."

      Sudden death risk?

      The current study involved health data on 10,318 adults, ages 45 and older, from Rotterdam. The data, which included information on each person's thyroid and heart health, were collected from 1990 to 1993, 2000 to 2001, and 2006 to 2008.
      After controlling for age, sex and various heart disease risk factors, such as smoking or high cholesterol, the researchers analyzed the data. They compared levels of thyroxine in blood samples of the adults with how many of them died of sudden cardiac death.