Colorectal Cancer More Common Among Diabetics

There's more evidence that people with Diabetes have a significantly higher risk of developing Colorectal cancer, investigators reported here.

In a cross-sectional analysis of 226,953 participants who participated in the National Health Interview Survey (NHIS) during 1997 to 2003, 13,399 (5.9%) reported a history of Diabetes, according to Donald Garrow, M.D., of the Medical University of South Carolina in Charleston and colleagues.

After controlling by multiple logistic regression for obesity, gender, race, and smoking status - all associated with both Diabetes and Colorectal cancer - respondents with Diabetes were significantly more likely to develop Colorectal cancer (OR = 1.39, 95% CI = 1.15-1.67), they reported at the American College of Gastroenterology meeting here.

Among the respondents, the rate of Colorectal cancer among those with Diabetes was 1.39%. For those without Diabetes, the rate was 0.47%.

The colon and rectum are part of the large intestine (large bowel). Colon and rectum cancers, which are sometimes referred to together as "colorectal cancer," arise from the lining of the large intestine. (When cancer arises from the lining of an organ like the large intestine, it is called a carcinoma.)

Other types of colon cancer are rare, and include lymphoma, carcinoid tumors, melanoma, and sarcomas. Use of the term "colon cancer" for the rest of this article refers to colon "carcinoma" and not the other, rare types of colon cancer.

Causes, incidence, and risk factors

There are over 130,000 cases of colorectal cancer diagnosed in the United States each year, and over 50,000 deaths. Colorectal cancer is the second leading cause of cancer deaths. In almost all cases, however, this disease is entirely treatable if caught early by colonoscopy.

"Earlier studies had looked at this question but they had been difficult to replicate because they were small or limited to one center," said Dr. Garrow.

Additionally, in vitro studies had shown that hyperinsulinemia and hyperglycemia promote the growth of Colorectal cancer, and that both insulin and insulin-like growth factor-1 (IGF-1) receptors had been associated with such malignancies. Further, high levels of circulating IGF-1 had been linked to both certain benign polyps and to cancer, he added.

Not surprisingly, people who were older than 50 were nearly 14 more times as likely to get Colorectal cancer. However, white respondents were 40% more likely to get , and obese respondents had a slightly lower risk, approximately 20%. Smoking and alcohol use were also associated with a slight elevation in risk, 43% and 10% respectively.