Today we explore weight and colon cancer.

“If you concentrate on small, manageable steps you can cross unimaginable distances.”
― Shaun Hick

EXCESS WEIGHT HAS A GREATER IMPACT on colorectal cancer risk than suggested by previous studies that did not consider cumulative lifetime exposure. That is the conclusion of a recent study from Heidelberg University (Germany).

We have long known that excess weight is a risk factor for colon and rectal cancer (as well as numerous other cancers), but risk estimates have historically been based on weight determined at a single time.

Today we look at a lifetime approach to understanding the relationship between excess weight and colorectal cancer.

Colorectal cancer risk factors

Here are some factors that may increase your risk of colon or rectal cancer, according to the Mayo Clinic (USA):

• Older age. While colorectal cancer can develop at virtually any age, most with the disease are over 50. Please note, however, that the rates of colorectal cancer among younger people are rising.
• African-American race.
• A personal history of colorectal polyps or cancer.
• Inflammatory intestinal conditions. Chronic inflammatory diseases of the colon (for example, ulcerative colitis and Crohn’s disease) can increase colon cancer risk.
• Inherited syndromes. Some inherited genetic mutations can increase your risk of colon cancer. Still, a small proportion of colorectal cancer is attributible to inherited genes. Common inherited syndromes that increase colorectal cancer risk include familial adenomatous polyposis (FAP) and Lynch syndrome (hereditary nonpolyposis colorectal cancer (HNPCC)).
• Family history of colon cancer. The risk increases with an increasing number of affected relatives.
• Low-fiber, high-fat diet. I think there is an association between a Western diet and colorectal cancer, but no high-level evidence of causality.
• A sedentary lifestyle. Sedentary individuals are more likely to develop colon cancer.
• Diabetes. Those with insulin resistance or diabetes have an increased risk of colon cancer.
• Obesity. Being obese increases colon cancer incidence and mortality.
• Smoking.
• Alcohol.
• Radiation therapy for cancer. Radiation therapy directed at the abdomen [or pelvis] to treat previous cancers can increase colorectal cancer risk.

Lifetime excess weight and colorectal cancer

The German study included over 10,000 individuals, over half with colorectal cancer. The subjects had a median age of 68 years. The researchers gathered information from an ongoing population-based control study from 2003.

Here are the results:

Analysis showed an association between the number of years being overweight or obese and colorectal cancer risk. The odds increased to over 2.5-times in the highest weight category when comparing the first and fourth quartiles of weight.

This research illustrates the value of metrics that characterize chronic exposures. I hope researchers use this approach to analyze the effects of excessive weight on other health outcomes and cancer.

Lifestyle changes to reduce your risk of colon cancer

Here are the steps I take to try to drop my risk of ever getting (or dying from) colorectal cancer:

• I don’t drink alcohol (if I did, I would do so in moderation: No more than one standard drink daily for women; two for men is thought best).
• I eat a mix of fruits, vegetables, and whole grains.
• I avoid tobacco.
• I exercise most days of the week. Somedays, the activity is vigorous; on others, I aim for a minimum of 30 minutes of walking.
• I maintain a healthy weight. Weight loss for adults (particularly those who are overweight or obese) may reduce their risk of developing a polyp type that can lead to colon or rectal cancer. That is according to a new study led by researchers at the University of Maryland School of Medicine (UMSOM) recently published here: JNCI Cancer Spectrum.
• I get colorectal screening as recommended.

Thank you for joining me for this look at weight and colon cancer risk.

The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider if you seek medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.