Blood Markers May Foretell Heart Disease; Lifestyle Can Forestall It
New study hints that biomarkers are predictive, but the key to prevention is healthful living
Who wouldn't like to make a dent in the heart disease problem? Despite years of improving mortality rates, it's still the leading cause of death for both sexes nationwide. Some fear that death rates may start rising again because of the increased prevalence of obesity. And so the hunt is on for tools to fight it.
One tactic, illustrated by a study published this week, is to attempt to sort out the individuals at greatest risk of the disease. The current Framingham risk score, based on factors like age and cholesterol measures, does a pretty good job of estimating risk on a population basis—say, figuring out that of 100 people with a set of given risk factors, 30 will get heart disease. The trouble is, it can't pinpoint who will be among the 30. Researchers in Sweden reported in the New England Journal of Medicine that among a uniform population—that is, Swedish men who were an average of 71 years old—looking for the presence of four biomarkers in the blood may help that risk stratification process. "Hopefully it's an important step," says study author Johan Arnlöv, a researcher at Uppsala University in Uppsala, emphasizing that his team's finding needs confirmation and further study to see if the biomarkers are ultimately useful tools.
Biomarkers that might signal hidden or impending disease are a hot topic now, as researchers hope to use them to predict cancer and other diseases in addition to heart disease. (U.S. News's Michelle Andrews recently wrote about a controversial blood test that can screen for a host of biomarkers.) But researchers say that while the discovery of novel biomarkers may eventually help doctors to predict who is at risk of disease, the immediate key to reducing heart disease among the general population is far simpler: Aggressively encourage everyone to make their lifestyle healthier.
"We don't have a heart disease epidemic because we don't know who's at risk but because we don't do a good job at reducing those risk factors," says Rita Redberg, director of women's cardiovascular services at the University of California-San Francisco. That means figuring out—and then funding—the best ways to promote a few basics that we know work: eating less and opting for healthier food, getting more exercise, and avoiding tobacco.
You might rather know whether you're really at risk before resigning yourself to eating veggies on the off chance that you are. But really, lifestyle improvement is good for you regardless of your odds of developing heart disease. After all, obesity, lack of exercise, and smoking put you at risk for a host of other diseases and problems. And drugs like statins and low-dose aspirin (the likely medical recommendation if you are at substantial risk) cannot always make up for those problems. A study published earlier this week in the Archives of Internal Medicine showed that obesity is associated with thicker carotid artery walls and other potential precursors of heart problems, even when people take preventive drugs. "We were looking to see if there's an additional amount of risk that cannot be explained by [traditional] risk factors," says study author Gregory Burke, director of the division of public health sciences at the Wake Forest University School of Medicine in Winston-Salem, N.C.
But while the traditional set of risk factors like blood pressure may tell only part of the story, your doctor can "do some thinking" and estimate whether you're at higher risk even without the help of new biomarkers, says Donald Lloyd-Jones, a cardiologist in the department of preventive medicine at the Feinberg School of Medicine at Northwestern University in Chicago and coauthor of an editorial accompanying the NEJM study. "You can look for extra features, like a strong family history or a physical exam finding," he says.
That more detailed assessment may or may not lead your doctor to add a prescription on top of lifestyle advice, since, for example, statins' risks sometimes outweigh their benefits. If a new biomarker is ever developed that truly helps inform that risk-benefit calculation, it will be valuable for those patients in the middle, both to determine whether they need medication and to motivate them to change their own habits, says Burke. But for now, there are bigger problems to tackle: Doctors aren't using the basic predictors of risk that they've got, says Lloyd-Jones, and Americans continue to gain weight and eschew exercise. "We are losing a battle we were poised to win," he says. Addressing those factors should be the priority, says Redberg. "We could stop right now doing any work on biomarkers and put our money into healthy lifestyle research," she says, to reap far bigger health gains.
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