Do low-fat foods alter risk of colorectal cancer from processed meat?

We investigated potential causes of the high incidence rate of colorectal cancer (CRC) in New Zealand.

A national population-based case-control study of 806 cases and 1025 controls was conducted to determine the risk factors for CRC in this population.

Information about family history of CRC, ethnicity, diet, school milk consumption, exercise, and height and weight at age 20 years were collected by a self-administered questionnaire from cases and controls.

Response rates were 84% for cases and 65% for controls. Increasing preference for low-fat food alternatives was associated with reducing odds ratios (OR) for CRC (P_trend<0.001) with a considerably reduced OR of always versus never choosing low-fat food alternatives (OR = 0.39, 95% confidence interval = 0.26, 0.58). Increased consumption of dairy products or milk was associated with reduced risk of CRC. Belonging to the male gender, having a first degree relative with CRC, and increasing consumption of processed meat, lamb, pork, and bread were associated with elevated risks of CRC. The increased risk from consumption of processed meat was not evident in subjects who regularly or always preferred low-fat food.

A preference for low-fat food may ameliorate an increased risk of CRC from the consumption of processed meat.