Comprehensive Assessment of Diet Quality and Risk of Precursors of Early-Onset Colorectal Cancer

Abstract

Background: The role of poor diet quality in the rising incidence of colorectal cancer (CRC) diagnosed younger than age 50 years has not been explored. Based on molecular features of early-onset CRC, early-onset adenomas are emerging surrogate endpoints.

Methods: In a prospective cohort study (Nurses' Health Study II), we evaluated 2 empirical dietary patterns (Western and prudent) and 3 recommendation-based indexes (Dietary Approaches to Stop Hypertension [DASH], Alternative Mediterranean Diet [AMED], and Alternative Healthy Eating Index [AHEI]-2010) with risk of early-onset adenoma overall and by malignant potential (high-risk: ≥1 cm, tubulovillous or villous histology, high-grade dysplasia, or ≥3 adenomas), among 29 474 women with 1 or more lower endoscopy before age 50 years (1991-2011). Multivariable logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

Results: We documented 1157 early-onset adenomas with 375 at high risk. Western diet was positively associated, whereas prudent diet, DASH, AMED, and AHEI-2010 were inversely associated with risk of early-onset adenoma. The associations were largely confined to high-risk adenomas (the highest vs lowest quintile: Western, OR = 1.67, 95% CI = 1.18 to 2.37; prudent, OR = 0.69, 95% CI = 0.48 to 0.98; DASH, OR = 0.65, 95% CI = 0.45 to 0.93; AMED, OR = 0.55, 95% CI = 0.38 to 0.79; AHEI-2010, OR = 0.71, 95% CI = 0.51 to 1.01; all Ptrend ≤ .03), driven by those identified in the distal colon and rectum (all Ptrend ≤ .04, except AMED: Ptrend = .14).

Conclusion: Poor diet quality was associated with an increased risk of early-onset distal and rectal adenomas of high malignant potential. These findings provide preliminary but strong support to the role of diet in early-onset CRC.

© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Figures

Figure 1.

Diet quality and risk of early-onset (aged younger than 50 years) adenoma according to size (A) and histology (B), Nurses’ Health Study II, 1991-2011. AHEI = Alternative Healthy Eating Index; AMED = Alternative Mediterranean Diet; CI = confidence interval; DASH = Dietary Approaches to Stop Hypertension; OR = odds ratio; Q1 = lowest quintile; Q5 = highest quintile. Odds ratio was adjusted for the covariates denoted in Table 2. Ptrend was calculated using the median of each quintile as a continuous variable.