Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


C-reactive proteins do not predict early osteoarthritis


C-reactive proteins, which are released into the bloodstream as a result of inflammation, may not be an accurate early predictive marker for chronic diseases such as osteoarthritis, according to a new study by Duke University Medical Center researchers. The finding calls into question the clinical usefulness of the proteins as an indicator of disease.

Instead, the researchers found, levels of C-reactive proteins circulating in the blood are more an indicator of a patient’s weight that can be influenced by gender and ethnicity. While not the elusive predictor for osteoarthritis that many rheumatologists have been seeking, C-reactive protein levels could serve as a useful indicator of an osteoarthritis patient’s response to therapy, according to the Duke researchers.

C-reactive proteins are produced by the liver in response to inflammation or infections, and their levels in the blood can rise dramatically in many chronic disease states. While previous studies by other researchers have suggested that elevated levels of C-reactive protein may be a predictive marker for disease, they did not take into account the role of weight or ethnicity, the Duke researchers said.

The results of the Duke study were presented March 7, 2004, at the 50th annual scientific meeting of the Orthopedic Research Society.

"Contrary to previous reports, the level of C-reactive protein in the blood is not a useful indicator of osteoarthritis because of its strong association with body mass index (BMI), the commonly used measure of obesity," said Duke’s Virginia Kraus, M.D., lead investigator for the study. "Additionally, C-reactive protein levels are higher in African-Americans and women in general, so gender and ethnicity must also be taken in account when interpreting C-reactive protein levels in diagnosing common chronic diseases."

To date, the gold standard for diagnosing osteoarthritis has been the X-ray. However, since this radiographic approach can only image bone and not cartilage, it has not been a useful tool for diagnosing early-stage disease. Clinicians had hoped that C-reactive protein levels, as measured in the blood, could provide this early predictor of osteoarthritis, said Kraus.

For her analysis, Kraus wanted to discover if there was a correlation between the levels of C-reactive proteins with the degree of osteoarthritis as measured by X-rays. She analyzed clinical data and blood samples collected by Joanne Jordan, M.D., of the University of North Carolina at Chapel Hill. Jordan directs the Johnston County, N.C., Osteoarthritis Project, an ethnically diverse sample of patients with osteoarthritis.

After ruling out patients with other disorders such as rheumatoid arthritis, Kraus had a sample of 670 patients. The sample was 49 percent African-American, 41.5 percent male, with an average age of 62.

Unlike previous studies, Kraus included BMI as one of the patient characteristics to be studied. The BMI is intended to take into account the relationship of weight and height, and it is calculated by dividing weight in kilograms by height in meters squared. The average BMI for the study was 30, with a range of 18.5 to 25 being considered normal.

"The levels of C-reactive protein were higher in African-Americans and women, and were strongly associated with BMI," Kraus said. "C-reactive protein levels were also strongly positively associated with all definitions of osteoarthritis based on radiographic status, with the levels increasing as the severity of the disease increased.

"However, after the statistical analysis, all these associations between C-reactive protein levels and degree of osteoarthritis were explained entirely by BMI differences," she concluded. "For that reason, we do not think that C-reactive protein levels can be a useful predictor of osteoarthritis."

It is known that the immune system molecule known as interleukin-6 (IL-6) is the primary activator of the C-reactive protein gene in the liver. Interestingly, according to Kraus, fat tissue, especially the "bad" fat that collects around the waist, is the major source of IL-6.

"This is what probably accounts for the strong relationship between C-reactive protein and BMI," she said. "We know that exercise has the ability to decrease levels of C-reactive proteins. For this reason, measuring C-reactive protein levels in our osteoarthritis patients who are prescribed exercise may give us useful information about how patients are responding to therapy."

Osteoarthritis is a growing national health issue, with more than 40 million Americans suffering from the disorder, known as the "wear-and-tear" form of arthritis. The other major form, rheumatoid arthritis, occurs when the body’s immune system attacks the linings of joints.

It is estimated that more than 70 percent of Americans over the age of 65 show some signs of osteoarthritis, which is characterized by the slow degeneration of the buffering layer of cartilage within joints. It occurs most commonly in knees, hips, hands, neck and the lower back.

The research was funded by a National Institutes of Aging Claude D. Pepper grant, the Centers for Disease Control/Association of Schools of Public Health, and the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Other members of the team included Duke’s Thomas Stabler, as well as G. Luta, J.B. Renner and A.D. Dragomir, University of North Carolina at Chapel Hill.

Richard Merritt | dukemed news
Further information:

More articles from Health and Medicine:

nachricht NIH scientists describe potential antibody treatment for multidrug-resistant K. pneumoniae
14.03.2018 | NIH/National Institute of Allergy and Infectious Diseases

nachricht Researchers identify key step in viral replication
13.03.2018 | University of Pittsburgh Schools of the Health Sciences

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Earlier flowering of modern winter wheat cultivars

20.03.2018 | Agricultural and Forestry Science

Smithsonian researchers name new ocean zone: The rariphotic

20.03.2018 | Life Sciences

Molecular doorstop could be key to new tuberculosis drugs

20.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>