1. ¹Division of Nutritional Epidemiology, The National Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-17177 Stockholm, Sweden
2. ²Departments of Nutrition and Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA
3. ³Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA
4. ⁴Department of Surgery and Centre for Clinical Research, Central Hospital, SE-72189 Västerås, Sweden

Correspondence: Dr SC Larsson, E-mail: susanna.larsson@imm.ki.se

Received 12 January 2005; Revised 25 February 2005; Accepted 25 February 2005; Published online 12 April 2005.

Abstract

We examined prospectively the association between whole grain consumption and colorectal cancer risk in the population-based Swedish Mammography Cohort. A total of 61 433 women completed a food-frequency questionnaire at baseline (1987–1990) and, through linkage with the Swedish Cancer Registry, 805 incident cases of colorectal cancer were identified during a mean follow-up of 14.8 years. High consumption of whole grains was associated with a lower risk of colon cancer, but not of rectal cancer. The multivariate rate ratio (RR) of colon cancer for the top category of whole grain consumption (4.5 servings day^-1) compared with the bottom category (<1.5 servings day^-1) was 0.67 (95% confidence interval (CI), 0.47–0.96; P-value for trend=0.06). The corresponding RR after excluding cases occurring within the first 2 years of follow-up was 0.65 (95% CI, 0.45–0.94; P-value for trend=0.04). Our findings suggest that high consumption of whole grains may decrease the risk of colon cancer in women.