Colorectal cancer rates could be reduced by nearly one-quarter if people adopted some lifestyle changes which include watching diet, smoking habits, exercise, alcohol consumption and waist size, Danish researchers wrote in an article published in the BMJ (British Medical Journal). 16,250 people die of colorectal cancer each year in the UK and 38,600 new diagnoses are made annually. Colorectal cancer is the second biggest cancer killer in the UK; it is also the third most common cancer in the country.

According to the American Cancer Society, colorectal cancer is the third most commonly diagnosed cancer in the USA. 49,470 men and 53,430 women are diagnosed with colon cancer every year in the USA, and 22,620 males and 17,050 females are diagnosed with rectal cancer.

Any cancerous growth, lump or tumor of the colon and rectum is a type of colorectal cancer, also known as bowel cancer. According to the World Health Organization, colorectal cancer is the second most common cancer globally after lung cancer. Although it mainly affects older adults, a US study found that rates among younger adults is increasing. Some of the signs and symptoms of bowel cancer may include going to the toilet more frequently, diarrhea, constipation, a lump in the back passage or tummy felt by the doctor, bloating in the abdomen, a feeling that you still need to do more after going to the toilet, blood in stools, a feeling of fullness in the abdomen (even when you have not eaten), vomiting, unexplained weight loss, and fatigue.

The authors explain that there is mounting and compelling evidence linking lifestyle factors, such as diet, alcohol consumption, smoking, and waist size to colorectal cancer risk.

The researchers set out to determine what impact lifestyle and lifestyle advice might have on colorectal cancer risk for middle-aged individuals. They also wanted to see whether bowel cancer (colorectal cancer) risk rose when people did not comply with the advice.

In this study, the investigators examined data on 55,487 individuals aged between 50 and 64 who had no history of cancer. They were monitored for over a decade until 2006. They selected that age group because younger people, especially those under 40 have an extremely low risk of developing colorectal cancer.

They were given a questionnaire to complete which included questions on their general state of health, reproductive factors and lifestyle habits. They were also given a food-frequency questionnaire in order to assess their nutritional habits over a twelve-month period.

The investigators created a lifestyle index with the help of health recommendations from Nordic Nutrition, World Cancer Research Fund and the World Health Organization, which included 30 minutes or more per day of physical activity, consuming no more than 7 alcohol drinks for women and 14 for men per week, not smoking, eating a healthy and balanced diet, and having a waistline of no more than 88cm for women and 102 for men.

678 individuals were diagnosed with colorectal cancer during the follow-up period.

After assessing participants’ compliance with each of the five lifestyle recommendations, the researchers worked out that if everyone, except for the healthiest participants, had adhered to just one additional recommendation the number of colorectal cancer cases would have been 13% lower. There would have been a 23% rate reduction if everyone had complied with all five recommendations, the scientists added.

The authors concluded:

Our study reveals the useful public health message that even modest differences in lifestyle might have a substantial impact on colorectal cancer risk and emphasizes the importance of continuing vigorous efforts to convince people to follow the lifestyle recommendations.

Another study, also published in the BMJ found that individuals with low levels of education who used a decision aid when contemplating whether to be screened for cancer were less likely to have one done, even though they were more informed. However, they authors stressed that the decision aid helped people with low education make an informed choice regarding screening.

“Association of adherence to lifestyle recommendations and risk of colorectal cancer: a prospective Danish cohort study”
Helene Kirkegaard, Nina Føns Johnsen, Jane Christensen, Kirsten Frederiksen, Kim Overvad, Anne Tjønneland
BMJ 2010; 341:c5504 doi: 10.1136/bmj.c550

Written by Christian Nrodqvist