Risk models were identified
via synthesis of 4 previous systematic reviews
5–8 and a supplemental PubMed search covering January 2023 to October 2024 (
Figure 1B). Briefly, we included models developed in screening populations that incorporated sociodemographic and environmental risk factors assessed by questionnaires, and predicted colorectal cancer or advanced adenomas confirmed by colonoscopy and pathology; detailed inclusion and exclusion criteria are provided in the
Supplementary material. Basic characteristics and model information are presented in
Tables S4–S6. Among the 17 models, approximately one-third were developed in Chinese populations, whereas the remainder originated predominantly from Europe and East Asia. Most models were developed in case–control settings, although 2 were derived from cohort studies. Across models, the predictor variables ranged from 3 to 9, and typically included age, sex, body mass index (BMI), smoking, alcohol consumption, and family history. The main characteristics of the validation cohort are shown in
Table S1. The missing rates of questionnaire-based covariates were very low (0.0%–3.29%). Therefore, missing values were not imputed; each covariate was treated as an exposure, and analyses were conducted on available data. Standardized mean difference analyses showed no statistically significant differences in demographic characteristics or lifestyle factors between FIT-positive individuals and the overall screening population (
Table S2), or between colonoscopy attendees and non-attendees among the FIT-positive participants (
Table S3), indicating that the validation cohort remained representative. Although development AUCs varied (0.60–0.74), validation outside the derivation populations was limited, heterogeneity in predictor definitions and model structure underscored the need for comparative validation using a standardized population and outcome definition.