A study conducted over a ten-year period followed almost 90,000 women between the ages of 40 and 59. In that period of time, 527 women developed colon cancer. Statistics from this study revealed that obese pre-menopausal women had twice the risk of developing the disease as women of normal weight. For post-menopausal women, the risk among those that were obese and those of normal weight was about equal.



Previous studies had determined that obese men have about forty percent higher risk for malignant large bowel tumors than men of normal weight. Until recently, these risk data had not been available for women.

While the data show some definite relationships between obesity and cancer, research has not actually established that obesity is a cause. Clearly, the puzzling discrepancy between data on menopausal and pre-menopausal women is enough to cast doubt upon any casual conclusion.

One thing is clear: human tissues are subject to an enormous number of hereditary, environmental and random factors, and the human body is an incredibly complex system. But medical researchers know that obesity complicates the effects of factors such as metabolism and hormones and the data cannot be ignored.

While one cannot conclude that obesity alone is the cause of bowel carcinomas, diets low in fiber and high in saturated fats have long been suspected as playing a role. Ongoing research is geared towards determining the true impact of diet and/or obesity on the development of this form of cancer.

In the case of colorectal cancer, body mass index (BMI) has been a less reliable measure of risk than fat distribution. The waist-to-hip ratio is used to measure fat distribution. This ratio establishes "abdominal adiposity," or the amount of fat on the abdomen. In women, the distribution of fat over the hips, thighs and buttocks is less likely to increase risk than fat concentrated on the abdomen.

One of the effects of obesity is resistance to insulin, which leads to chronically high levels of insulin in the blood. New research indicates a clearer connection between abdominal adiposity, insulin resistance, and colon cancer. The study results, published in the Journal of the National Cancer Institute, showed that those with the highest levels of blood insulin following an oral glucose test also had the highest risk for developing the disease.

The American Cancer Society reports that:

Colorectal? Colon? Bowel? You will find several terms to describe carcinomas of the large intestine. Some prefer the term "large bowel" while others use the term "colorectal" to include both the colon and rectum. The terms used often depend on whether the research has been conducted in the U.S. or the U.K., and on the types studied.

Many people have no symptoms at all until the tumors have reached advanced stages. This is why people in high-risk groups should get regular colonoscopies. If you notice any of these symptoms, make an appointment to visit your doctor as soon as possible:

More information is available at Colon Cancer Symptoms.