Dietary patterns and their impacts on colorectal cancer in Newfoundland and Labrador

Abstract

Dietary habits have long been regarded as an important environmental factor which may contribute to or prevent chronic health conditions, such as colorectal cancer (CRC). This thesis aims to derive the major dietary patterns and explore the association with CRC in the Newfoundland and Labrador (NL) population using two existing databases. It is presented in a manuscript format that includes three complementary papers focusing on the topic of dietary patterns and CRC. The first paper examines the dietary patterns in the general NL population and the assessment of whether these patterns vary according to demographic characteristics. The second paper relates the derived dietary patterns with CRC risk in this population. The third paper assesses the reliability of the identified dietary patterns by comparing them with those from another study several years later using identical methods in the NL population. Overall, findings from this thesis suggest a four-factor dietary pattern (i.e., Meat pattern, Vegetables/Fruits pattern, Fish pattern, Grain pattern). Further, results suggest that the Meat-diet and the Sugary-diet increased the risk of CRC with corresponding odds ratios (ORs) of 1.84 (95% CI: 1.19-2.86) and 2.26 (95% CI: 1.39-3.66) for people in the highest intake quintile compared to those in the lowest. Whereas plant-based diet pattern decreased the risk of CRC with a corresponding OR of 0.55 (95% CI: 0.35-0.87). The reliability study suggests that the identified NL dietary patterns are reasonably stable overtime and across studies. This thesis provides more evidence to support healthy eating for the primary prevention of CRC in the NL population.