ASPIRIN may help reduce the risk of colorectal cancer (CRC) among individuals with unhealthy lifestyles, according to recent research conducted at Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA, and collaborating institutions.
Followed for nearly four decades, the research involved over 107,000 participants from two major cohort studies: the Nurses’ Health Study (1980–2018) and the Health Professionals Follow-Up Study (1986–2018). The aim of the study was to determine whether the benefits of regular aspirin use for CRC prevention vary based on lifestyle factors.
The team used a healthy lifestyle score, which accounted for BMI, alcohol intake, physical activity, diet, and smoking, with scores ranging from 0–5 (with higher values corresponding to healthier lifestyles). Regular aspirin use was defined as consuming two or more standard aspirin tablets (325 mg) per week. The primary outcome was the incidence of CRC over a 10-year period, adjusted for various factors.
Results showed a significant reduction in CRC risk among regular aspirin users. The 10-year cumulative incidence of CRC was 1.98% among aspirin users compared to 2.95% among non-users, corresponding to an absolute risk reduction (ARR) of 0.97%. Notably, the greatest benefit was observed in individuals with the least healthy lifestyles. For those with the unhealthiest lifestyle scores (0–1), the ARR was 1.28%, while it dropped to 0.11% for those with the healthiest scores (4 to 5). The 10-year number of people needed to treat to prevent one case of CRC varied from 78 in lifestyle groups 0–1, to 909 in groups 4–5.
These findings suggest that aspirin’s protective effects against CRC are most pronounced in individuals with less healthy lifestyles, including higher BMI, higher alcohol intake, regular tobacco use, lower levels of physical activity, and poor diet. These lifestyle risk factors may be useful to identify individuals with a more favourable risk-benefit profile for CRC prevention with aspirin.
Ada Enesco, EMJ
Reference
Sikavi DR et al. Aspirin use and incidence of colorectal cancer according to lifestyle risk. JAMA Oncol. 2024; DOI:10.1001/jamaoncol.2024.2503.
