Getting a colonoscopy dramatically reduced the risk, the results showed.
The findings, published in JAMA Network Open, suggest that colonoscopies are particularly important for people with diabetes. People diagnosed with diabetes within the past 5 years have the greatest colorectal cancer risk, the study found, suggesting screening should be part of a person’s health care after they’re diagnosed with diabetes.
Researchers analyzed data for 54,597 people who contributed at least 2 years of health data as part of a study that recruited people from 12 Southeastern states between 2002 and 2009. The people self-reported their diabetes status, and although researchers tried to only include people with type 2 diabetes, it’s possible that some people in the study had type 1 diabetes. The average age of those in the study was 51 years old; 64% were women; more than half of them had an income of less than $15,000 per year; and 66% of them were African American.
Among the people in the study who had diabetes, the risk of having colorectal cancer was not strongly impacted by their race or ethnicity, gender, weight, or income level, the study showed.
While race didn’t predict whether people with diabetes would get colorectal cancer, the findings are particularly important because most of the people in the study were African American. Diabetes and colorectal cancer disproportionately affect African American people, the authors noted. Medical research studies often struggle to recruit people of color, resulting in a lack of data to help guide health care priorities and decision-making.
The study also provided important guidance for people newly diagnosed with diabetes. People who were diagnosed with diabetes within the past 5 years were at a particularly increased risk of getting colorectal cancer, compared to people who had been diagnosed for 5-10 years.
The authors concluded that increased referrals for colonoscopies among people with diabetes, particularly among those newly diagnosed, could greatly reduce the impact of colorectal cancer. Current guidelines suggest most people should begin colorectal cancer screenings at age 45, according to the Centers for Disease Control and Prevention.
The study was supported by the National Cancer Institute and the University of Wisconsin, Madison. The study authors reported no relevant conflicts of interest.
A version of this article first appeared on WebMD.com.