Dietary patterns and subsequent risk of colorectal cancer (CRC)/colorectal adenoma among Japanese adults aged 60 and older

This study aims to explore the risk factors for colorectal cancer (CRC) and colorectal adenoma in Japanese adults aged ≥ 60, focusing on dietary patterns. The data utilized in the analysis were obtained from St. Luke’s International Hospital between 2015 and 2018. The numbers of patients with CRC ( n = 12,845) and colorectal adenomas ( n = 10,896) were assessed as the outcome. Dietary patterns were identified using principal component analysis (PCA), and their associations with the incidence of CRC and colorectal adenoma were evaluated using Cox proportional hazards models. In the CRC study, no statistical associations were observed regardless of any dietary patterns ( p > 0.05). In the case of colorectal adenomas, significant associations were identified, with a negative association for the “good meal timing” pattern and a positive association for the “fast eating and frequent dining out” pattern. The observed heterogeneity in associations highlights the complexity of dietary influences on colorectal neoplasia. Given the inherent limitations of a self-reported questionnaire in health check-ups, further research is warranted to refine dietary assessments and account for variations in intake methods, ultimately enhancing our understanding of diet-related colorectal carcinogenesis.