Association between Low-Dose Aspirin Use and Colorectal Cancer Incidence using Japanese Large-scale Health Insurance Claims Data
Menée à partir de données 2005-2021 de l'Assurance maladie japonaise portant sur 69 492 témoins et 17 373 patients atteints d'un cancer colorectal, cette étude analyse l'association entre une utilisation de faibles doses d'aspirine et le risque de développer la maladie
Background: While experimental studies suggest low-dose aspirin has chemopreventive effects against colorectal cancer, clinical evidence remains inconsistent, and studies on Japanese populations are limited. This study aimed to evaluate the relation between low-dose aspirin and colorectal cancer using a large-scale Japanese database.
Methods: A nested case-control study was conducted using a health insurance claims database (2005–2021). Cases were defined as patients with a diagnosis of colorectal cancer during the study period, with the month of the first diagnosis as the index month, and were matched 1:4 risk-set sampling with population controls based on age and sex. Exposure was defined as the use of low-dose aspirin prior to the index month. We further analyzed recency and duration. Recency was categorized as recent use (< 3 months before the index month) and past use (≥ 3 months before the index month). Duration was classified into two groups: < 2 years and ≥ 2 years.
Results: In total, 17,373 cases and 69,492 controls were included. Conditional logistic regression analysis, adjusted for patient background, showed that low-dose aspirin use may reduce the risk of colorectal cancer (adjusted odds ratio: 0.87, 95% confidence interval: 0.79–0.97). For recency and duration, the risk of colorectal cancer was significantly reduced by recent use and ≥ 2 years compared to never use.
Conclusions: Low-dose aspirin use may be associated with a reduced risk of colorectal cancer.
Impact: These findings contribute to the clinical evidence regarding colorectal cancer prevention in Asian populations.
Cancer Epidemiology, Biomarkers & Prevention , article en libre accès, 2026