Elevated plasma C-peptide levels are typically associated with a condition called hyperinsulinemia, in which insulin in the body can rise to damaging levels. Plasma C-peptide levels are higher among individuals who are overweight, less physically active and follow a Western dietary pattern, characterized by high consumption of red meat, high-fat dairy products and refined grains. This study suggests that this elevated level of insulin, which could be attributed to several behaviors including a Western diet, sedentary lifestyle and being overweight, contribute significantly to colorectal cancer risk.
According to study's lead researcher, Jing Ma, MD, PhD of BWH, "This study supports our hypothesis that men with long-term elevated insulin production, as a result of long-term exposure to Western dietary and lifestyle risk factors, are at a much higher risk of developing colorectal cancer in their lifetimes. This information, in conjunction with the growing awareness of the severe health risks associated with poor diet and exercise, can help physicians best manage disease risk in their patients."
Ma and her colleagues looked at the histories of 22,071 men who were enrolled in the Physicians' Health study and were followed for 13 years. Among these healthy US physicians, 14,916 provided blood samples at the time of study enrollment. Within this group, Ma and her colleagues compared plasma C-peptide levels among 176 men who were diagnosed with colorectal cancer with 294 who were cancer-free. They found that men who have an elevated plasma C-peptide level had a three-times higher risk of developing colorectal cancer. An elevated plasma C-peptide is defined as levels in the top 20 percent of the distribution of the 294 cancer-free men, compared with C-peptide levels in the lowest 20 percent.
According to Ma, "By reducing risk factors associated with high insulin production, specifically through modifying dietary behaviors and exercising more, individuals can take their health into their own hands and significantly lower risks associated with this deadly disease."
Colorectal cancer (which includes cancer of the colon, rectum, anus, and appendix) is the second-leading cause of cancer-related deaths in the United States. This year, nearly 131, 000 Americans will be diagnosed with colorectal cancer and 56,000 will die.