Revealing Inflammation

You may have read about the “new” C-reactive protein (CRP) blood test that can help predict heart disease risk. CRP’s use as a marker for cardiovascular problems may be relatively new, but scientists have known the value of CRP for indicating the presence of inflammation for more than 60 years.

Now a new study shows that a CRP test may also be a good indicator of risk for a very common type of cancer – and it’s a cancer that’s more successfully treated when caught early.
Getting a clue

As I’ve told you in previous e-Alerts, C-reactive protein is produced by the liver in response to inflammation. Over the years, researchers have found high levels of CRP to be associated with various chronic health problems, including stroke and diabetes. Recently, a team headed by researchers at the Johns Hopkins Bloomberg School of Public Health, reported on a population-based study designed to see if there’s a link between elevated CRP levels and colorectal cancer.

Researchers used data collected from a study called CLUE II (named for a campaign called “Give Us a Clue to Cancer and Heart Disease”), conducted in Maryland. The records of nearly 23,000 adults included blood tests and health questionnaires. Additional data was gathered on the subjects for more than 10 years.

The Hopkins team identified 172 cases of colorectal cancer, and compared the data for these cases against 342 control subjects who were cancer-free, but matched the cancer subjects by age, sex and race.

The results showed that CRP levels were about the same among those with rectal cancer and subjects in the control group. But researchers determined that CRP levels were significantly higher among those with colon cancer. Overall, the highest levels of CRP indicated double the risk of developing colorectal cancer and two and a half times the risk of colon cancer, compared with subjects with the lowest CRP levels.

Writing in a recent issue of the Journal of the American Medical Association, Thomas P. Erlinger, M.D. (lead author of the study), noted that although elevated CRP was clearly linked to colorectal and colon cancer risk in this study, further research is needed in order to define exactly how CRP measurements might be used in screening and prevention of the diseases.

Inside peek

Because CRP levels can be measured with a simple blood test, this inflammation marker is quickly becoming one of the most critical tools in assessing risk of chronic health problems. So the next time you have a physical exam, ask your doctor to check your CRP. If it’s elevated, and if you also have a family history of colorectal cancer, your doctor will probably suggest that you have a colonoscopy exam – especially if you’re over the age of 50.

The importance of managing the development of colon polyps can’t be overstated. An estimated 10% of all cancer deaths in the U.S. are the result of colorectal cancer, and the key to prevention of the disease is colonoscopy, which not only looks for cancer polyps, but also removes them. When precancerous polyps are removed, the risk of developing colorectal cancer is sharply reduced.


Beyond CRP and colonoscopy

In three previous e-Alerts I examined studies that reveal simple steps you can take to help prevent colorectal and colon cancer.

In the e-Alert “Mass Communication” (1/13/04), I told you about a study of more than 3,000 subjects, aged 50 to 75 years, who were screened for colon cancer. Using dietary questionnaires, researchers found a clear association between vitamin D intake of more than 645 IU per day and a reduced risk of colon cancer. Those who had the greatest protection also used multivitamins, exercised regularly, and had diets with high fiber content. Moderate sun exposure, wild salmon and cod liver oil supplements are excellent sources of vitamin D.

Multivitamin use was also examined in a 2003 study conducted by the American Cancer Society. More than 145,000 subjects participated in the study that ran between 1992 and 1997. Researchers found that among subjects who began taking multivitamins just prior to the 1992 enrollment, there was no association with a reduced risk of colorectal cancer. But the participants who had reported regular multivitamin use (4 or more times per week) in the early 80s, fared much better: their group had a 30 percent reduced risk of the cancer.

And in the e-Alert “Invoking the 25th” (7/11/02), I told you about a University of Minnesota study of more than 1,700 subjects that showed how a diet containing ample amounts of fruits and vegetables may be a significant factor in preventing precancerous polyps from developing into cancer. Results also showed that women who drank the most fruit juice reduced their risk of developing polyps by half. The researchers speculate that the high folate intake from orange juice probably contributed to this resistance to polyp development. Why this “juice effect” didn’t hold true for men couldn’t be answered by the study.

Exactly how CRP levels may be affected by dietary factors, multivitamin use and vitamin D remains to be seen. In the meanwhile, it appears that the growing importance of CRP now includes a novel way to help predict colorectal cancer.

To Your Good Health,

Jenny Thompson
Health Sciences Institute

Sources:
“C-Reactive Protein and the Risk of Incident Colorectal Cancer” Journal of the American Medical Association, Vol. 291, No. 5, jama.ama-assn.org
“Inflammation Marker Predicts Colon Cancer” Johns Hopkins Medical Institutions Press Release, 2/5/04, sciencedaily.com
“Risk Factors for Advanced Colonic Neoplasia and Hyperplastic Polyps in Asymtomatic Individuals” Journal of the American Medical Association, vol. 290, no. 22, 12/10/03, ncbi.nlm.nih.gov
“Vitamin D Reduces Colon Cancer” Dr. Joseph Mercola, 1/3/04, mercola.com
“Fruits, Vegetables, and Adenomatous Polyps – The Minnesota Cancer Prevention Research Unit Case-Control Study” American Journal of Epidemiology, Vol. 155, 2002, aje.oupjournals.org

- See more at: http://hsionline.com/2004/03/22/c-reactive-protein-blood-test/#sthash.Q7kjNDnK.dpuf