By Bruce Sylvester

WASHINGTON, DC — May 22, 2007 — Lifelong vegetarianism is strongly correlated to a reduced risk of colon cancer, researchers reported here at Digestive Diseases Week (DDW).

"This large study adds new proof to the concept that lifelong vegetarianism can protect against colorectal cancer, possibly even prevent it," said investigator and presenter Yogesh Shastri, MD, clinical fellow, Johann Wolfgang Goethe University Hospital, Frankfurt, Germany.

Dr. Shastri reported the finding here at a press briefing on May 21st. He led the study while affiliated with Tata Memorial Hospital, Mumbai, India.

The investigators prospectively developed a database of 8,877 patients managed in a clinical nutrition service from January 1, 2000 through December 31, 2005. They analysed the data for an association of lifelong vegetarianism with incidence of colorectal cancer. The investigators obtained a history of vegetarianism (due to religious reasons) from all subjects. Subjects with already diagnosed colorectal cancer (n = 796) made up the primary patient cohort for the study.

The researchers created 3 groups of controls out of the same database and used them for separate comparisons with the colorectal cancer cohort. These included subjects with noncolorectal cancers (control group 1, n = 7,273), patients with noncolorectal cancer and tobacco-related cancers (control group 2, n = 1,844), and patients with benign disorders (control group 3, n = 74).

Twenty-seven percent of subjects (2,092 patients) from the control cohort were lifelong vegetarians and 22.4% (178 patients) of subjects already diagnosed with colon cancer were vegetarians.

The researchers also performed multivariate analysis of data on 7,641 patients to adjust findings for age, gender, body mass index, and economic status.

The investigators found that lifelong vegetarianism was significantly associated with age over 65 years, male gender, body mass index (BMI) of less than 20 kg/m2, and economic deprivation.

Colorectal cancer was positively associated with old age and male gender.

Colorectal cancer was significantly and inversely associated with vegetarian diet, low BMI, and economic deprivation.

Most notably, the inverse association of colorectal cancer and lifelong vegetarianism was observed in all 3 control groups.

"Use of diseased controls is a limitation of this study," the authors noted.

[Presentation title: Life Long Vegetarian Diet Reduces the Risk of Colorectal Cancer. Abstract 155]