Low-Dose Aspirin and Prevention of Colorectal Cancer: Evidence From a Nationwide Registry-Based Cohort in Norway

Q: What is the primary research question of the study?

The study examines the association between low-dose aspirin use and the risk of colorectal cancer (CRC).

Q: How was the nationwide cohort study conducted?

Individuals aged 50 or older residing in Norway for at least 6 months during 2004–2018 were identified and linked to national registers for prescriptions, cancer occurrence, and sociodemographic factors. Multivariable Cox regression estimated the association with CRC risk.

Q: What did the study find about CRC risk and aspirin use?

Current low-dose aspirin use was associated with a lower CRC risk versus never use (HR 0.87). The association was more pronounced for metastatic CRC and showed a significant trend with increasing duration of current use.

Sep 21, 2026

Uploaded by Maeve

Nationwide cohort evidence evaluates how low-dose aspirin use relates to colorectal cancer (CRC) risk. Participants aged 50+ living in Norway for at least 6 months during 2004–2018 were followed using national registers for drug prescriptions, cancer occurrence, and sociodemographic factors. Multivariable Cox regression quantified CRC risk and estimated CRC cases potentially averted. Results show lower CRC risk for current users versus never users, with stronger effects for metastatic CRC and a duration-related trend.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Introduction

Methods

Results

Discussion

Keywords

1402 ARTICLE COLON Low-Dose Aspirin and Prevention of Colorectal Cancer: Evidence From a Nationwide Registry-Based Cohort in Norway Sara Nafisi, MSc1 ,2, Nathalie C. Støer, PhD1, Marit B. Veierød, PhD2, Kristin R. Randel, PhD3, Geir Hoff, PhD3 ,4 ,5, Lukas Lfling, PhD 1 , Cristina Bosetti, PhD6 and Edoardo Botteri, PhD 1 ,3 INTRODUCTION: To examine the association between low-dose aspirin use and risk of colorectal cancer (CRC) . METHODS: In this nationwide cohort study, we identified individuals aged 50 years or older residing for 6 months or more in Norway in 2004–2018 and obtained data from national registers on drug prescriptions, cancer occurrence, and sociodemographic factors. Multivariable Cox regression models were used to estimate the association between low-dose aspirin use and CRC risk. In addition, we calculated the number of CRC potentially averted by low-dose aspirin use. 1Department of Research, Cancer Registry of Norway, National Institute of Public Health, Oslo, Norway; 2Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway; 3Section for Colorectal Cancer Screening, Cancer Registry of Norway, National Institute of Public Health, Oslo, Norway; 4Department of Research and Development, Telemark Hospital Trust, Skien, Norway; 5 Institute of Clinical Medicine, University of Oslo, Oslo, Norway; 6Department of Medical Epidemiology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy. Correspondence: Edoardo Botteri, PhD. E-mail: [edoardo.botteri@kreftregisteret. no](edoardo.botteri@kreftregisteret. no). Received July 21, 2023; accepted January 24, 2024; published online February 1, 2024 The American Journal of GASTROENTEROLOGY VOLUME 119 | JULY 2024 [www.amjgastro.com](www.amjgastro.com) Low-Dose Aspirin and Prevention of CRC RESULTS: We included 2,186,390 individuals. During the median follow-up of 10.9 years, 579,196 (26.5%) used low-dose aspirin, and38,577(1.8%)were diagnosed with CRC. Current use of aspirin vs never use was associated with lower CRC risk (hazard ratio [HR] 0 .87, 95% confidence interval [CI] 0 .84–0.90) . The association was more pronounced for metastatic CRC (HR 0.79; 95% CI 0.74–0.84) than regionally advanced(HR0.89;95%CI0.85–0.92)and localized CRC(HR0.93;95%CI0.87–1.00; P heterogeneity 5 0.001) . A significant trend was found between duration of current use and CRC risk: HR 0.91 (95% CI 0.86–0.95) for <3 years, HR 0.85 (0.80–0.91) for ‡3 and <5 years, and HR 0.84 (0.80–0.88) for ‡5 years of use vs never use (P trend < 0.001) . For past use, HR were 0.89 (95% CI 0.84–0.94) for <3 years, 0.90 (0.83–0.99) for ‡3 and <5 years, and 0.98 (0.91–1.06) for ‡5 years since last use vs never use(P-trend < 0.001). We estimated that aspirin use averted1,073cases ofCRC (95% CI 818–1,338) in the study period. DISCUSSION: In this nationwide cohort, use of low-dose aspirin was associated with a lower risk of CRC. KEYWORDS: aspirin; incidence; colorectal cancer; cohort study SUPPLEMENTARY MATERIAL accompanies this paper at [http://links.lww.com/AJG/D194](http://links.lww.com/AJG/D194) , [http://links.lww.com/AJG/D195](http://links.lww.com/AJG/D195) , and [http://links.lww.com/AJG/D196](http://links.lww.com/AJG/D196) Am J Gastroenterol 2024;119:1402–1411. [https://doi.org/10.14309/ajg.0000000000002695](https://doi.org/10.14309/ajg.0000000000002695) INTRODUCTION In 2020, colorectal cancer (CRC) had the third highest incidence rate and second highest mortality rate of all cancers worldwide, imposing substantial burden on individuals and health systems (1) . Public health strategies aiming to ease this burden include developing screening programs for prevention and early detection ofCRC(2,3)and raising awareness about harmful lifestyle habits that increase CRC risk, including physical inactivity, overweight and obesity, alcohol consumption, cigarette smoking, and poor diet (4

FAQs

What is the primary research question of the study?

The study examines the association between low-dose aspirin use and the risk of colorectal cancer (CRC).

How was the nationwide cohort study conducted?

Individuals aged 50 or older residing in Norway for at least 6 months during 2004–2018 were identified and linked to national registers for prescriptions, cancer occurrence, and sociodemographic factors. Multivariable Cox regression estimated the association with CRC risk.

What did the study find about CRC risk and aspirin use?

Current low-dose aspirin use was associated with a lower CRC risk versus never use (HR 0.87). The association was more pronounced for metastatic CRC and showed a significant trend with increasing duration of current use.

Sep 21, 2026

Uploaded by Maeve