Aspirin associated with colorectal cancer risk reduction in those with less healthy lifestyles
The least healthy patients had a 1.28% 10-year absolute risk reduction in colorectal cancer with aspirin use compared to only 0.11% among the healthiest patients who took aspirin, according to retrospective data from nurses and health professionals.
Regular aspirin use is associated with a greater absolute risk reduction of colorectal cancer (CRC) among adults with less healthy versus healthier lifestyles, a recent study found.
The study included 63,957 women from the Nurses' Health Study and 43,698 men from the Health Professionals Follow-Up Study who were followed for three decades. All participants completed biennial questionnaires on lifestyle factors, disease outcomes, and medication use. Participants' average age at baseline was 49.4 years. Each participant's healthy lifestyle score was calculated based on body mass index (BMI), alcohol intake, physical activity, diet, and smoking, with higher values indicating a healthier lifestyle. Investigators defined regular aspirin use as two or more 325-mg tablets per week or six or more 81-mg tablets per week. Findings of the prospective cohort study were published by JAMA Oncology on Aug. 1.
A total of 2,544 incident cases of CRC were documented during 3,038,215 person-years of follow-up. Ten-year cumulative CRC incidence was 1.98% (95% CI, 1.44% to 2.51%) in regular aspirin users versus 2.95% (95% CI, 2.31% to 3.58%) in nonusers (absolute risk reduction [ARR], 0.97%; number needed to treat [NNT], 103). Data showed the ARR with aspirin use was greatest among participants with unhealthy lifestyles and steadily decreased as lifestyle scores increased (P<0.001). The participants with the least healthy lifestyles (lifestyle scores of 0 to 1) had a 10-year ARR of 1.28% (NNT, 78), compared with 0.11% (NNT, 909) among the participants with the healthiest lifestyles (lifestyle scores of 4 to 5). Of the factors included in the lifestyle score, the greatest differences in ARR associated with aspirin use were found with BMI and smoking status.
One limitation to the study is that it only included health professionals and they were predominantly White. Exposure data were also self-reported, and researchers did not systematically assess adverse outcomes potentially related to aspirin use.
Overall, “these results support the use of lifestyle risk factors to identify individuals who may have a more favorable risk-benefit profile for cancer prevention with aspirin,” the researchers concluded.