Getting people to eat a healthy diet, not smoke, cut down on alcohol and exercise more could prevent almost a quarter of the some 1.2 million cases of colon cancer diagnosed each year, scientists said on Wednesday.

Researchers from Denmark found that following recommendations on physical activity, waist circumference, smoking, alcohol intake and diet could reduce the risk of developing bowel cancer by as much as 23 percent.

“Our study reveals the useful public health message that even modest differences in lifestyle might have a substantial impact on colorectal cancer risk,” said Anne Tjonneland of the Institute of Cancer Epidemiology at the Danish Cancer Society, who led the study.

Colorectal cancer, often referred to as bowel or colon cancer, kills around half a million people each year worldwide.

The disease was diagnosed in 1.23 million people in 2008, according to the International Agency for Research on Cancer.

Tjonneland and colleagues studied data on 55,487 men and women aged between 50 and 64 who had not previously been diagnosed with cancer and followed them for almost 10 years.

Participants filled in lifestyle and diet questionnaires and the researchers created a healthy lifestyle index using health recommendations from the World Health Organization, World Cancer Research Fund and the Nordic Nutrition Recommendations.

These included not smoking, doing at least 30 minutes a day of physical activity, having no more than seven drinks a week for women and 14 drinks a week for men, having a waist circumference below 88 cm (35 inches) for women and 102 cm (40 inches) for men, and eating a healthy diet.

The results, published in the British Medical Journal, showed that during the follow-up period, 678 people were diagnosed with bowel cancer.

After analyzing how well the participants had kept to the five lifestyle tips, the researchers calculated that if all of them had followed even one extra guideline, around 13 percent of colon cancer cases could have been prevented. If all of them had followed all five, 23 percent of cases could have been avoided.

Previous studies have identified 14 gene variations that each increase the risk of developing colorectal cancer by between 1.5 and 2 times, and a study published last month found how a single variant in a person’s genetic code can lead to the development of the disease.

But experts say a having good diet and healthy lifestyle are likely to play a far greater role in a person’s colon cancer risk. Tjonneland said the findings emphasized the importance of continuing “vigorous efforts to convince people to follow the lifestyle recommendations.”

SOURCE:  BMJ, online October 26, 2010.