DALLAS, Oct. 21 -- Physicians may need to pay closer attention to an individual's triglyerceride levels, according to researchers who say the blood fat is a "strong gauge" of a person's risk of heart attack. The findings appear in today's Circulation, a journal of the American Heart Association.
Triglycerides are compounds in the blood made up of fatty acids and glycerol that bind to proteins and form low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL). LDL and VLDL contain large amounts of cholesterol and triglycerides that can adhere to the arteries in the form of fatty plaque. HDL is the "good" cholesterol because it transports cholesterol and other fats from the bloodstream.
Physicians often combine LDL and HDL, as a cholesterol ratio, to predict a person's risk of heart disease. However, it has been unclear whether triglyceride levels were as strongly tied to heart attack risk, according to J. Michael Gaziano, M.D., director of cardiovascular epidemiology at Brigham and Women's Hospital in Boston.
"The ratio of triglycerides to HDL was the strongest predictor of a heart attack, even more accurate than the LDL/HDL ratio," says Gaziano. Compared with the lowest triglyceride/HDL ratios, those with the highest had a 16-fold greater risk of a heart attack.
"If the new findings that triglycerides are a strong marker for heart disease are confirmed by other studies, clinical trials to develop new treatments to reduce triglyceride levels might be worthwhile," says Gaziano. "Ultimately, screening and treatment guidelines may require modification to allow greater attention to be paid to fasting triglycerides."
Gaziano and colleagues compared triglyceride and cholesterol levels in 340 heart attack survivors and an equal number of healthy individuals. High triglyceride levels were strongly associated with heart attack risk. By combining the triglyceride level measurement with the cholesterol in a ratio provided an even stronger gauge of heart attack risk.
The metabolic relationship between triglycerides and cholesterol remains unclear, according to Gaziano, however, the findings suggest that a high ratio of triglycerides to HDL could prove to be a valuable marker for abnormal triglyceride metabolism, as well as heart attack risk.
Triglyceride levels are elevated when enzymes responsible for breaking down fats in the bloodstream are less active. Their decreased activity results in higher VLDL and lower HDL levels, both of which are strongly associated with cardiovascular disease and heart attacks. Decreased activity might also result in longer circulation of harmful VLDL and smaller, dense LDL particles.