Doctors have long used tests of low-density lipoprotein (LDL) cholesterol ( the “bad” cholesterol that can lead to blood clots and heart attacks) to assess heart disease risk.
For the new study, researchers wanted to see if testing for two additional things — a type of fat in the bloodstream known as lipoprotein(a) and a marker of inflammation called C-reactive protein — might provide a more accurate picture of long-term heart health.
To find out, researchers collected blood samples and detailed medical information from about 28,000 women when they were in their mid-fifties, then followed them for 30 years. During the study period, over 3,500 participants had a heart attack, stroke, surgery to restore circulation, or died of cardiovascular-related causes.
Women with the highest levels of LDL cholesterol were 36 percent more likely to experience these cardiovascular events than participants with the lowest LDL levels. Similarly, the risk of these events was increased by 33 percent for women with the highest lipoprotein(a) levels.
Most dramatically, women with the highest C-reactive protein levels saw their risk of heart disease increase by 70 percent compared with women with the lowest levels.
In addition, women with the highest levels on all three lab tests were almost 3 times more likely to develop heart disease and about 1.5 times more likely to experience a stroke than participants with the lowest results on these three tests.
Doctors Can Screen for All 3 Risk Factors With a Blood Test
“We need universal screening for all three,” says lead study author Paul Ridker, MD, a professor at Harvard Medical School and director of the Center for Cardiovascular Disease Prevention at Brigham and Women’s Hospital in Boston. “LDL cholesterol is very important and we have universal screening for it which is great, but cholesterol only tells us one part of the problem and there are many individuals whose problem is related to inflammation.”
Testing for all three shouldn’t be hard for patients to do, because these tests are simple, widely available, and possible to do with a single blood draw, Dr. Ridker says. They’re also widely covered by insurance.
The study does have some limitations. The vast majority of participants were white women, making it possible that results might differ for men or for people from other racial or ethnic groups. In addition, the lab tests were only done once, and it’s possible that changes in participants’ health over time might have influenced the connection between the test results and heart disease risk.
Lifestyle Changes Can Reduce Risk if a Blood Test Signals Danger
The results suggest that it may make sense for people to consider getting all three tests in their fifties, when they’re still young enough to make meaningful changes if their levels of LDL cholesterol, lipoprotein(a), or C-reactive protein are too high, says Roger Blumenthal, MD, a cardiology professor and director of the Ciccarone Center for the Prevention of Cardiovascular Disease at Johns Hopkins Medicine in Baltimore.
“With long term follow-up, these simple blood tests can be helpful for identifying when lifestyle changes are needed to reduce cardiovascular risk,” says Dr. Blumenthal, who wasn’t involved in the new study.
That’s because when the tests come back high, indicating an increased heart disease risk, it’s absolutely possible to get those levels down and reduce the risk with targeted lifestyle interventions, Blumenthal says.
Anyone who smokes should make quitting a top priority to reduce their risk, Blumenthal says. Adopting a Mediterranean style diet, rich in whole fruits and veggies, fish, and lean protein, can also help. So can aiming for 20 to 30 minutes of exercise every day, whether it’s a brisk walk, a bike ride, or going to the gym.
“The cornerstone of prevention is emphasizing lifestyle habits,” Blumenthal says. “Meaningful lifestyle changes can make a difference in three to six months, and medication can also be considered at that point if the lab tests are still too high.”
