In America, it’s well known that race and ethnicity affect who gets colon cancer screenings. But now it appears that where people live also determines whether or not they’ll get screened, according to a study published in the journal Cancer and reported in a news release from the University of California Davis Health System.

Colon cancer (a.k.a. colorectal cancer) is the fourth most common cancer in men and women.

For the study, researchers analyzed data of 53,990 people on Medicare, ages 69 to 79, from 11 regions in the United States. With the exception of Asian-Pacific Islanders in Hawaii, scientists found that whites were more likely than non-whites to have regular colorectal screenings. (This means they had a colonoscopy or sigmoidoscopy—currently the gold standard tests for colon cancer—within the past five years or a fecal occult blood test within the past year.)

Asian-Pacific Islanders had the highest screening rates with more than half recently screened for colon cancer compared with 38 percent of whites.

Asian-Pacific Islanders are very aware of the importance of screenings because gastrointestinal cancer is common among Hawaii’s Japanese population, said Thomas Semrad, MD, the study’s lead researcher.

As for the low rates of screenings among other ethnicities in the United States, Semrad suggested that these people may be visiting medical practices that don’t offer colorectal cancer screenings.

Researchers need to look at different geographic areas to see what the screening determinants are for minorities, Semrad said. “Are these culturally based? Are there problems with how health care systems are set up? What are the barriers? If we can figure this out, we would have a target to improve some of these disparities.”

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