Subjects with a family history of colon cancer and whose average alcohol intake was 30 or more grams a day — about 2 1/2 typical drinks by U.S. standards — had an increase in their risk of colon cancer, according to findings from the Nurses' Health Study and Health Professionals Follow-up Study.

There was no significant association between alcohol consumption and colon cancer among study subjects without a positive family history.

The study involved more than 87,000 women from the Nurses' Health Study and 47,000 men from the Health Professionals Follow-up Study. The researchers found 1,801 cases of colon cancer during follow-up from 1980 onward.

In addition to the links with family history and alcohol intake, those at greatest risk also ate the most red meat, smoked the most and had the lowest intake of folate, suggesting they ate fewer green vegetables and cereals. Hence the highest-risk study subjects had the most unhealthy lifestyles in general.

Study reviewers noted that the pattern of drinking (including frequency and binge drinking) was not assessed, and there was not a consistent increase in the risk of cancer with greater reported alcohol intake. Also, adequate folate was found to lower risk, indicating the importance of other lifestyle factors such as a healthy diet.

The authors also noted changes in the guidelines for colon cancer screening and other preventive measures for people with a family history of the disease, increasing the difficulty of drawing conclusions about 30-year-old data for colon cancer. At least some cases could have been prevented if managed according to current guidelines, and such measures could modify the effects of all risk factors for colon cancer in future analyses.

The study appears in the February issue of the American Journal of Clinical Nutrition. To read a summary and access it via subscription or purchase, visit http://bit.ly/yXyAlc.