That's what researchers from the Veterans Administration Medical Center in Portland wanted to find out.
The researchers write that since 1985, colon cancer rates have dipped 20% to 25% for whites, while rates have gone up for African-American men and stayed the same for African-American women.
They add some startling figures: that African-Americans are 38% to 43% more likely to die from colon cancer than are whites.
For this study, researchers looked at where polyps (larger than 9 millimeters) were located in African-Americans and whites who were screened but had no symptoms. They also compared how prevalent those polyps were in both races.
Information came from colonoscopy screenings of 5,464 African-Americans and 80,061 whites from 67 screening centers around the United States.
The authors write that "asymptomatic black men and women undergoing colonoscopy screening are more likely to have one or more polyps sized more than 9 mm compared with white individuals. The differences were especially striking among women. These findings emphasize the importance of encouraging all black men and women to be screened."
Colon Cancer and Race
Nearly 8% of African-American patients had one or more polyps larger than 9 mm.
6% of whites had one or more polyps larger than 9 mm.
African-American women had a 62% greater risk of having such a polyp in the colon when compared with white women.
African-American men had a 16% greater chance of having large polyps when compared with white men.
Researchers write that these differences cut across all ages in both women and men.
The study was carried out and led by David Lieberman, MD, of Portland VA Medical Center.
The findings were adjusted for age, sex, and whether the participants had a family history of colon cancer. Increased risk for large polyps was seen in people over 50 and went up with age but seemed to level off after 80 years of age.
The researchers also found that there was a significant increase in prevalence of large polyps found in the proximal colon (beginning part of the colon) for African-American patients over 60 years old compared with white patients over 60.
The results are published in the Sept. 24 issue of The Journal of the American Medical Association.