How does thyroid disease affect my cholesterol level?
One of the observed side effects of hypothyroidism is an elevation of LDL cholesterol, the “bad cholesterol.” Elevated LDL levels have been associated with heart disease, particularly coronary artery disease, and peripheral vascular disease. Elevated triglycerides also pose a serious medical problem. However, only in the most severe cases of hypothyroidism does the disease cause a marked elevation in triglyceride levels.
The “good cholesterol” is called HDL cholesterol. Scientific studies are inconclusive about the effects of hypothyroidism on HDL levels. Some have shown a decrease; others have shown no change; and a few have shown a minimal increase.
All patients with hypercholesterolemia (high cholesterol) should have tests of their thyroid function since a small percentage of these patients will have hypothyroidism contributing to their cholesterol problem. Treatment with thyroid hormone will lower cholesterol levels in those patients with an abnormal cholesterol from hypothyroidism.
The overall effect of hypothyroidism is a significant increase in the bad cholesterol. Long-standing, untreated hypothyroidism can lead to permanent damage to the coronary arteries and other blood vessels. Therefore, it is important to treat hypothyroidism and monitor cholesterol levels closely.