Skip to main content

Screening for heart disease by measuring levels of C-reactive protein does not provide enough useful information to make the highly touted screening test worthwhile, a new study concludes.

In fact, people with high levels of CRP -- a protein released by the liver that points to inflammation of blood vessels -- invariably are either smokers, obese, have high blood pressure or elevated cholesterol levels, so the additional test is redundant, said Michael Miller, director of preventive cardiology at the University of Maryland Medical Center in Baltimore.

"We believe that high C-reactive protein is truly related to the company it keeps," he said.

Story continues below advertisement

The research, published in today's edition of the Archives of Internal Medicine, found that one in four people tested had elevated CRP.

But three-quarters of the 15,000 participants whose records were analyzed had traditional risk factors for heart disease.

"If you exercise, don't smoke, have normal levels of blood pressure, cholesterol and glucose, and are not overweight, the likelihood of a high CRP is only one in 2,000," Dr. Miller said.

If anything, the CRP blood test provides a false sense of security to those at high risk of heart attack but whose livers are not producing the protein, the researcher said.

Overall, 25.7 per cent of people in the study had elevated CRP, including 8.7 per cent who had no other risk factors.

The analysis found a high CRP level in 78 per cent of men and 67 per cent of women who had at least one other risk factor for cardiovascular disease.

Dr. Miller said the money spent on CRP testing would be better used on programs to help people quit smoking and lose weight.

Story continues below advertisement

The CRP test became popular in the early 1990s, when it was believed that only half of heart attacks could be explained by traditional risk factors such as poor nutrition, a sedentary lifestyle, stress and the changes in blood pressure and cholesterol they produce.

But, Dr. Miller said, that "turned out to be one of the greatest myths of cardiovascular disease" and, in fact, more than 90 per cent of heart attacks could be attributed to traditional risk factors.

Many researchers have cautioned that there is no evidence that CRP causes heart disease. Others argue that CRP is as important a measure as cholesterol.

Both high cholesterol and high CRP are treated with heart drugs called statins.

While there is good evidence that this is beneficial for patients with a history of heart disease, the jury is still out on whether lowering CRP and/or cholesterol is beneficial for healthy people.

What the new research suggests is that CRP is, at best, a marker, in the same way that grey hair is a marker of aging.

Story continues below advertisement

Regardless, the best way to lower CRP -- and blood pressure and cholesterol for that matter -- is to lose weight, be active, and not smoke.

"Let's work more intensively to reduce the known culprits," Dr. Miller said.

Cardiovascular disease is the leading cause of death in Canada. According to Statistics Canada, 74,600 people died of heart disease in 2002, the most recent year for which data are available.

Report an error Editorial code of conduct
Comments

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff. Non-subscribers can read and sort comments but will not be able to engage with them in any way. Click here to subscribe.

If you would like to write a letter to the editor, please forward it to letters@globeandmail.com. Readers can also interact with The Globe on Facebook and Twitter .

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff. Non-subscribers can read and sort comments but will not be able to engage with them in any way. Click here to subscribe.

If you would like to write a letter to the editor, please forward it to letters@globeandmail.com. Readers can also interact with The Globe on Facebook and Twitter .

Welcome to The Globe and Mail’s comment community. This is a space where subscribers can engage with each other and Globe staff.

We aim to create a safe and valuable space for discussion and debate. That means:

  • All comments will be reviewed by one or more moderators before being posted to the site. This should only take a few moments.
  • Treat others as you wish to be treated
  • Criticize ideas, not people
  • Stay on topic
  • Avoid the use of toxic and offensive language
  • Flag bad behaviour

Comments that violate our community guidelines will be removed. Commenters who repeatedly violate community guidelines may be suspended, causing them to temporarily lose their ability to engage with comments.

Read our community guidelines here

Discussion loading ...

Due to technical reasons, we have temporarily removed commenting from our articles. We hope to have this fixed soon. Thank you for your patience. If you are looking to give feedback on our new site, please send it along to feedback@globeandmail.com. If you want to write a letter to the editor, please forward to letters@globeandmail.com.
Cannabis pro newsletter