Aspirin More Effective in Reducing CRC Risk Among People With Less Healthy Lifestyles

A prospective cohort study of 107,655 men and women who took the equivalent of 2 or more standard aspirin tablets (325 mg) per week found that those with the most unhealthy lifestyle factors saw the greatest reduction in the risk of developing colorectal cancer (CRC).

Investigators analyzed data from 63,957 women who participated in the Nurses’ Health Study (1980-2018) and 43,698 men in the Health Professionals Follow-Up Study (1986-2018). They calculated healthy lifestyle scores ranging from 0 to 5, which higher values associated with a healthier lifestyle, based on body mass index, alcohol intake, physical activity, diet, and smoking.

“Outcomes included multivariable-adjusted 10-year cumulative incidence of CRC, absolute risk reduction (ARR), and number needed to treat associated with regular aspirin use by lifestyle score and multivariable-adjusted hazard ratios for incident CRC across lifestyle scores,” the researchers wrote in JAMA Oncology. “During 3,038,215 person-years of follow-up, 2544 incident cases of CRC were documented. The 10-year cumulative CRC incidence was 1.98% (95% CI, 1.44%-2.51%) among participants who regularly used aspirin compared with 2.95% (95% CI, 2.31%-3.58%) among those who did not use aspirin, corresponding to an ARR of 0.97%.”

The study revealed that the 10-year ARR for the unhealthiest lifestyle scores (0 to 1) was 1.28%, while the 10-year ARR for lifestyle scores 4 to 5 was 0.11%. The number needed to treat with aspirin over 10 years was 78 for those with lifestyle scores 0 to 1; 164 for those scoring 2; 154 for score 3; and 909 for participants with the healthiest scores of 4 to 5. “

“Among the components of the healthy lifestyle score, the greatest differences in ARR associated with aspirin use were observed for body mass index and smoking,” the authors wrote, adding “the findings of the study suggest that lifestyle risk factors may be useful to identify individuals who may have a more favorable risk-benefit profile for cancer prevention with aspirin.”

Reference:

Sikavi DR, Wang K, Ma W, et al. Aspirin use and incidence of colorectal cancer according to lifestyle risk. JAMA Oncol. Published online August 1, 2024. doi:10.1001/jamaoncol.2024.2503