Researchers affiliated with the Nurses’ Health Study have reported that women with a high risk factor profile for developing colon cancer can reduce risk by a healthier lifestyle. The details of this study appeared in the October 2009 issue of the American Journal of Epidemiology.[1]

Most studies have shown that an increased intake of red and processed meats is associated with an increased incidence of colorectal cancer. Increased dietary fiber has been more controversial, with both positive and negative studies reported. Fat intake does not seem to be an adverse risk factor, but obesity is clearly a risk factor. There has been very little convincing data that vitamin supplementation affects colorectal cancer, and there is the suspicion that natural foods are more preventive than artificial vitamins. Exercise also appears to be an important factor in preventing colorectal cancer. Researchers from Australia have recently reported that exercise, diet, and lifestyle choices are key factors in preventing colon cancer.

In the current study, researchers developed a model of colon cancer incidence based on 701 cases among 83,767 participants in the Nurses’ Health Study that occurred between 1980 and 2004.

The following factors increased the risk of colon cancer:

• A positive family history of colon or rectal cancer = +55%
• 10 or more years pack-years of smoking before age 30 years = +16%
• Tallness, 67 inches versus 61 inches = +19%

The following factors decreased the risk of colon cancer:

• Current postmenopausal hormone use = -23%
• Physically active: 21 metabolic equivalent hours/week versus 2 metabolic equivalent hours/week = -49%
• Taking aspirin, 7 tablets/week versus none = -29%
• Colorectal screening = -24%

They also reported: “Women who smoked, had a consistently high relative weight, had low physical activity, consumed red or processed meat daily, were never screened, and consumed low daily amounts of folate had a 4-fold increased risk of colon cancer by age 70 years.”

They also suggested that women with a high risk profile can lower their risk of colon cancer by adopting a healthier lifestyle.

Comments: Although there is nothing new in this study, it provides very useful estimates about the impact of various risk factors in colon cancer development. This study also emphasizes the importance of behavior modification and screening in lowering the risk of developing colon cancer.

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