High Blood Sugar Puts Women at Increased Risk for Colon Cancer
People with high blood sugar levels and Type 2 diabetes are at a greater risk for many health problems, including certain types of cancers. Often, diabetics carry excess weight and body fat which increase the risk of cancer as well. A new study of postmenopausal women link elevated blood sugar levels and an increased risk of colorectal cancer, one of the leading causes of cancer-related deaths in the United States.
Researchers with Albert Einstein College of Medicine of Yeshiva University observed 4,902 non-diabetic postmenopausal women aged 50 to 79 enrolled in the National Institutes of Health’s Women’s Health Initiative study. Fasting blood sugar and insulin levels were measured at baseline and then several more times over the next 12 years. By the end of the study period, 81 of the women had developed colorectal cancer – cancer that starts in the large intestine or the rectum.
The women with the highest blood glucose levels at baseline were found to have nearly twice the risk of developing colorectal cancer as those with the lowest levels, regardless of BMI (body mass index, or level of obesity). The results were similar when the researchers looked at the repeated glucose measurements over the 12-year study timeframe.
Because obesity often accompanies Type 2 diabetes, and elevated insulin levels are also a factor, scientists have often believed that the increase in risk in cancer for diabetic patients was primarily due to high levels of circulating insulin. However, there was no association found between insulin levels and risk for colorectal cancer in this study, leaving the researchers the challenge of finding the mechanism by which chronically high levels of blood glucose increase the risk for cancer.
Dr. Geoffrey Kabat PhD, a senior epidemiologist and lead study author, said, “It’s possible that elevated glucose leads to, or is correlated with, increased blood levels of growth factors and inflammatory factors that spur the growth of intestinal polyps, some of which later develop into cancer.”
The American Cancer Society notes that colorectal cancer is the third most commonly diagnosed cancer and the third leading cause of cancer death for US men and women.
A previous study conducted at the University of California, Berkeley suggests that people with diabetes begin screening for colorectal cancer at an earlier age than non-diabetics.
Kabat G PhD, Kim M ScD, Strickler H MD, Rohan TE MD PhD. “A Longitudinal Study of Serum Insulin and Glucose Levels in Relation to Colorectal Cancer Risk among Postmenopausal Women.” Published in the November 29 online edition of the British Journal of Cancer.