Supplementary Table 1 – Patterns of colorectal cancer diagnosis among younger adults in a real-world, population-based cohort

Supplementary Table 1. Patterns of colorectal cancer diagnosis among younger adults in a real-world, population-based cohort Demographics and health behaviors of different health zones within Alberta according to Canadian Community Health Survey Abstract: Objective: To review the patterns of early onset (Methods: This is a retrospective, population-based study based on Alberta administrative databases. Income level was identified through linkage with dissemination area income information from Canadian census 2006. Patients with colorectal adenocarcinoma diagnosed from 2004-2018 were included in the current analysis. Frequency analyses were used to examine the percentage of early-onset colorectal cancer cases across the study duration among different subgroups. Multivariable logistic regression analysis was used to examine factors associated with the development of early-onset colorectal cancer. Results: A total of 24912 patients were included in the current study; including 2096 patients (8.4%) who were diagnosed at an age younger than 50 years and 22816 patients (91.6%) who were diagnosed at an age of > 50 years. The percentage of patients diagnosed at an age younger than 50 years increased over time (10.2% in 2018 versus 7.9% in 2004; PConclusion: Proportion of patients with early-onset colorectal cancer has increased in Alberta (out of the overall colorectal cancer population) throughout the study duration (particularly left-sided colorectal cancer). There is a need to reassess the current age limits of colorectal cancer screening in Canada in view of these findings.