High levels of triglycerides — a type of fat that circulates in your bloodstream — can signal an increased risk of heart disease, but not always. It depends on why they are elevated in the first place, said Dr. James A. Underberg, a clinical assistant professor of medicine at NYU Langone Medical Center and the director of the Bellevue Hospital Lipid Clinic.
The American Heart Association sets the normal threshold for triglycerides at 150 milligrams per deciliter of blood. Some people have a genetic disorder that causes their levels to climb above 1,000, which puts them at risk for complications like pancreatitis, “but they don’t seem at risk for heart disease,” Dr. Underberg said.
Triglycerides can also rise as a side effect of certain medications, as well as from obesity and increased alcohol consumption.
Many people with Type 2 diabetes or at risk for it have a syndrome called “diabetic dyslipidemia” characterized by high triglycerides and a low concentration of “protective” HDL cholesterol. Levels of LDL, or “bad” cholesterol, may be normal in these people, but often they have a plethora of small, dense LDL particles that contribute to inflammation and raise heart disease risk.
While some studies cite high triglycerides as an independent risk factor for heart disease, others suggest it is hard to separate the impact of triglycerides from other factors. In a large analysis of studies published in Circulation in 2007, for example, researchers found a strong association between high triglycerides and coronary heart disease. But taking into account factors like HDL levels weakened the association between triglycerides and cardiovascular risk.
“What I tell my patients is that triglycerides themselves probably don’t cause heart disease,” Dr. Underberg said. “But for many people they can be a marker of increased risk — a warning sign that you need to look for things like small, dense LDL particles, low HDL, hypertension and diabetes.”