Published December 3 in The Lancet, the study found that adults under age 45 who had high levels of bad cholesterol and at least two other cardiovascular risk factors (such as high blood pressure and smoking) were more likely to have a heart attack or stroke by age 75 compared with adults age 60 and over with the same characteristics. Study authors suggest that younger adults with bad cholesterol levels may face these higher odds of heart trouble because of longer exposure to harmful fats or fat-like substances in the blood. “A doubling in non-HDL cholesterol is associated with a three- to fourfold increased risk of heart disease events. This is seen in men and women and evident at young ages,” says an author of the study, James de Lemos, MD, a professor of internal medicine in the division of cardiology at UT Southwestern Medical Center in Dallas. “Non-HDL is a simple measurement that contains essentially all the lipid particles that put us at risk for atherosclerosis,” he says. “The study highlights the powerful predictive value of non-HDL cholesterol for future cardiovascular risk.”
How Cholesterol Affects the Likelihood of Heart Disease
Dr. de Lemos and his collaborators based their analysis on medical data from almost 400,000 people in 19 countries who were followed for up to 43.5 years (an average of 13.5 years) between 1970 to 2013. During follow-up, there were 54,542 fatal or nonfatal cases of heart disease and stroke. Researchers observed that women who were younger than 45 years old who had high non-HDL cholesterol (between 3.7 and 4.8 millimoles per liter) and at least two additional cardiovascular risk factors had a 16 percent probability of experiencing a heart disease event by age 75. For women age 60 or over with the same characteristics, the estimated risk was 12 percent. For men, the risk was 29 percent for those under 45 and 21 percent for those 60 and over. RELATED: Heart Attacks Increasingly Strike Those Under 40 On the other hand, scientists calculated that the women under 45 who halved their non-HDL cholesterol levels could cut their heart-trouble risk from 16 percent to 4 percent. In men under 45 who did the same, heart risk could drop from 29 to 6 percent. “The results reflect the newer thinking that earlier intervention in reducing cholesterol will prevent events at older ages,” says Eleanor Levin, MD, a cardiologist at Stanford Health Care in Palo Alto, California, who did not work on this research.
Why Not Just Look at LDL Levels?
In a common blood test, a lipid panel will show levels of good cholesterol (HDL, or high-density lipoprotein) and bad cholesterol (LDL, or low-density lipoprotein). Although high LDL is an indicator for an increased risk of heart disease, some people with low LDL still have heart attacks and strokes. Some researchers now believe that measuring non-HDL is a much more accurate predictor of heart disease risk. “Non-HDL cholesterol includes other atherogenic particles [which promote fatty plaques in the arteries] besides LDL, so the measure gives us a clearer indication of somebody’s risk versus simply using LDL cholesterol,” says Sarah Samaan, MD, a cardiologist with Baylor Scott & White Legacy Heart Center in Plano, Texas, who was not involved in the study. “It is also an easy and inexpensive way to assess apolipoprotein B, which is strongly associated with cardiovascular disease.”
How to Build Healthier Cholesterol Levels
On the basis of these study results, Dr. de Lemos advises all adults to pay attention to their non-HDL number in addition to LDL. “Diet, exercise, and if necessary medications like statins are all effective ways to lower non-HDL,” he says. Dr. Levin says that individuals need to pay attention to their weight, quit smoking, and manage their stress as well to maintain optimal heart health. For advice on developing a healthy lifestyle, check out these recommendations from the American Heart Association. If non-HDL levels remain high even with a healthy lifestyle, Levin suggests that statins may help. “I often do recommend that young adults with high cholesterol on a good diet consider medication,” says Levin. “This is especially important with a family history of heart disease. I remind young women that statins are dangerous to the fetus in pregnancy, and to stop immediately if pregnant or planning pregnancy.” Levin notes that as an observational retrospective study, the research was limited compared with a randomized controlled investigation. De Lemos indicates that future research may explore how drug and lifestyle interventions influence cholesterol levels. According to Levin, research is already underway to find new treatments for high triglycerides (a type of fat in the blood) and newer treatments for high LDL.
