Hypertension, high cholesterol, diabetes, and smoking are traditionally considered the main risk factors of heart disease, the leading cause of death for both men and women. But a new study suggests that women may still be at risk for cardiovascular disease, even in the absence of any of these classic contributors.
The research, published in August in the European Heart Journal, found that inflammation—as measured by blood levels of high-sensitivity C-reactive protein (hsCRP)—was strongly associated with heart attack and other cardiovascular events in women who had none of the usual warning signs.
While it’s long been clear that inflammation elevates heart attack risk, prior studies have looked at it alongside other risk factors, explained study author Paul Ridker, MD, MPH, director of the Center for Cardiovascular Disease Prevention at Harvard University. “The people in this study had none of those, and thus would be totally missed by the risk algorithms doctors routinely use,” he told Health.
Ridker and his colleagues wanted to understand the role inflammation might play in the “substantial proportion” of heart disease cases involving people with no standard modifiable risk factors, also known as SMuRFs. They focused on women, not men, because women are often underdiagnosed and undertreated for heart disease.
First, researchers measured high-sensitivity C-reactive protein in 12,530 healthy American women with none of the classic SMuRFs—hypertension, high cholesterol, diabetes, and smoking.
A high hsCRP could indicate chronic inflammation, the type that can result from long-term health problems and eventually lead to heart issues, Harlan Krumholz, MD, SM, a professor of Cardiology at Yale School of Medicine, told Health.
The team then analyzed how frequently these women died from heart issues or developed major adverse cardiovascular events like heart attack, coronary revascularization, or ischemic stroke over the course of 30 years.
Despite lacking standard risk factors, women with high levels of hsCRP were significantly more likely to experience adverse cardiovascular events than those with lower levels. “Inflammation, measured by the hsCRP blood test, is at least, if not more, predictive of future heart attack and stroke than is cholesterol,” Ridker said.
According to Joy Gelbman, MD, a cardiologist at Weill Cornell Medicine, these results aren’t necessarily surprising. “We know that inflammation is a key driver of nearly every step in the continuum, from plaque formation to plaque rupture, cancause dysfunction of the vessel walls, promote lipid buildup, and cause cholesterol plaque to become unstable,” she told Health.
While the study didn’t include men, Ridker noted that inflammation drives heart disease risk in everyone—suggesting the findings may apply more broadly.
Ridker said the study highlights a big concern: Women with high inflammation but no standard risks may be more likely to fall through the cracks of screening—especially if physicians aren’t looking at inflammation levels as a predictor of cardiovascular disease. “Doctors will not treat what they don’t measure,” he noted.
So is this a call to get your hsCRP levels checked on a regular basis? It depends whom you ask.
Krumholz said there’s no reason for every woman to now beeline to the doctor’s office. “Elevated hsCRP can cause worry, and many people with high hsCRP will never develop heart disease,” he said. “The vast majority of cardiovascular disease is still explained by the traditional risk factors.”
For some patients, other tools—like a coronary calcium scan, which can directly show whether there’s silent plaque in the arteries—may be more useful.
But Gelbman said the test could help catch an elevated risk that might otherwise be missed for women without red flags like high cholesterol and smoking. She suggests avoiding checking hsCRP levels during an acute illness, though, since they may be unusually high at that time.
Fortunately, whether you check your hsCRP levels or not, lifestyle habits can help bring them into a heart-healthy range. “Many of the same lifestyle habits we already recommend for heart health—exercise, healthy eating, adequate sleep, avoiding smoking—also help lower hsCRP,” Krumholz said.
