Abstract
Background
The role of poor diet quality in the rising incidence of colorectal cancer (CRC) diagnosed under age 50 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 two empirical dietary patterns (Western and prudent) and three 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/villous histology, high-grade dysplasia, or ≥ 3 adenomas), among 29474 women with ≥1 lower endoscopy before age 50 (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 of high-risk. Western diet was positively, 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 (OR [95% CI] for the highest versus lowest quintile: Western = 1.67 [1.18 to 2.37]; prudent = 0.69 [0.48 to 0.98]; DASH = 0.65 [0.45 to 0.93]; AMED = 0.55 [0.38 to 0.79]; AHEI-2010 = 0.71 [0.51 to 1.01]; all P trend≤.03), driven by those identified in the distal colon and rectum (all P trend≤.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.
Time Lapse to Colorectal Cancer: Telomere Dynamics Define the Malignant Potential of Polyps