NEW ORLEANS, Nov.11, 1996 -- Triglyceride, a type of blood fat, must be considered more seriously as a risk factor for heart disease, especially at levels that today are thought to be safe, according to a new study. In an 18-year follow-up of 460 adults, the researchers found that people with triglyceride levels as low as 100 milligrams per deciliter (mg/dl) were more than twice as likely to suffer from future heart disease than those with less triglyceride. Today, levels below 200 mg/dl are thought to be desirable.
³Previously, nobody thought triglyceride was a major risk factor at these low levels,² says Michael Miller, M.D., director of Preventive Cardiology at the University of Maryland Medical Center in Baltimore and an assistant professor of medicine at the University of Maryland School of Medicine. ³We were surprised that in our study, it turned out to be such an important predictor of future heart disease, including heart attack and requiring bypass surgery or angioplasty,² says Dr. Miller, who will present the findings today at the American Heart Association¹s 69th Scientific Sessions.
In the study, Dr. Miller and his colleagues followed 460 men and women age 30 to 80 who had been evaluated for coronary artery disease in 1977-78. They contacted them to see how many had experienced a heart attack, had required a procedure to open up blocked heart vessels, or had died from heart disease.
After adjusting for other risk factors such as smoking, hypertension, diabetes, lack of physical activity, low levels of HDL (the ³good² cholesterol) and high levels of LDL (the ³bad² cholesterol), the researchers found that triglyceride was an independent risk factor for heart disease, even at lower levels.
³It turns out from our study that people with triglyceride levels in the low 100¹s had about the same risk for heart disease as those with diabetes. In light of that, we may need to re-evaluate current guidelines,² says Dr. Miller.
He adds that in the study, the risk did not go up with increasing levels of triglyceride. It remained a significant predictor of heart disease at 200 mg/dl, at 150 mg/dl, and at 100 mg/dl, the lowest level that the researchers evaluated.
According to current guidelines by the National Cholesterol Education Program, a blood triglyceride level of less than 200 mg/dl is considered safe.
Triglyceride is a type of fat that is always circulating in the blood, especially after a meal high in saturated fat. These fat particles are normally broken down by enzymes. When that process is not working efficiently, the triglycerides that are only partially broken down can cause fatty deposits in blood vessels, leading to atherosclerosis, known as hardening of the arteries.
Dr. Miller says we can enhance the breakdown of these fats by doing regular exercise, eating a diet low in saturated fat, and eating foods that are high in omega 3 fatty acids. Those include fresh fish, such as salmon, herring, mackerel, and sardines and tuna that is either fresh or packed in water, not oil.
Dr. Miller¹s co-authors were Azita Moalemi, M.D., Alexander Seidler, Ph.D., and Naghmeh Tebyanian, M.D., from the University of Maryland Medical Center in Baltimore and Thomas A. Pearson, M.D., Ph.D., from the Mary Imogene Bassett Hospital in Cooperstown, N.Y.