Strawberries in a bowl

July 28, 2017

HONOLULU – A high-quality diet was related to a lower risk of colorectal cancer as well as other chronic diseases by University of Hawaiʻi Cancer Center researchers using data from the Multiethnic Cohort (MEC) Study.

A high-quality diet was assessed by scores computed for four key diet quality indexes (DQIs), which measure compliance with dietary guidelines that have been issued to the United States population.

Dietary data scores consist of adequacy components

  1. Foods to eat more of, such as fruit, vegetables, whole grains, nuts, and legumes: higher score for higher intake and moderation components
  2. Foods to eat less of, such as red and processed meat, alcohol, refined grains, sodium, and sugar-sweetened beverages (e.g., sodas): higher score for lower intake

The MEC is a prospective epidemiological study in which 215,000 residents of Hawaiʻi and Los Angeles, aged 45-75 at recruitment in 1993-1996, completed a questionnaire about their dietary habits. The participants are being followed for occurrence of cancer and other chronic diseases.

"After an average follow-up of 16 years, participants with the highest scores for the four indexes experienced a lower risk of colorectal cancer, compared with those with the lowest scores," said Dr. Song Yi Park, the lead author of the study.

The study also shows that improvement in diet quality between middle age and late adulthood was associated with a lower risk of colorectal cancer in most racial/ethnic subgroups. High-quality diet was related to a colorectal cancer risk reduction of:

  1. 16 to 31 percent in men
  2. 4 to 18 percent in women
  3. 22 to 30 percent in Native Hawaiians
  4. 6 to 24 percent in Japanese Americans
  5. 17 to 31 percent in Whites

Colorectal cancer in Hawaiʻi

  1. Colorectal cancer is the 3rd most frequently diagnosed cancer in Hawaiʻi
  2. There are 722 new cases and 224 deaths annually.
  3. Colorectal cancer mortality is highest among Native Hawaiians.

"The study is one of the first to investigate how overall diet quality is in relation to colorectal cancer risk. We are seeking to find the best approach to achieving a health promoting diet in Hawaiʻi and across the nation," said Dr. Loic Le Marchand, study lead and professor in the UH Cancer Center's Cancer Epidemiology Program.

The analysis was performed as part of the Dietary Patterns Methods Project, which is led and supported by the National Cancer Institute.

Publication

High-Quality Diets Associate With Reduced Risk of Colorectal Cancer: Analyses of Diet Quality Indexes in the Multiethnic Cohort