September 2024
Aspirin use linked with reduced colorectal cancer risk in people with less healthy lifestyles
By Melanie Hinze
Aspirin use may be associated with a reduced risk of colorectal cancer among individuals with less healthy lifestyles, according to research published in JAMA Oncology.
The study authors conducted a prospective cohort study of women from the Nurses’ Health Study (1980-2018) and men from the Health Professionals Follow-Up Study (1986-2018), with data analysed between 2021 and 2023.
Healthy lifestyle scores were calculated based on participants’ body mass index, alcohol intake, physical activity, diet and smoking, with scores ranging from 0 to 5, where 5 corresponded to the healthiest lifestyle.
A total of 107,655 participants (mean age 49.4 years; 59.4% women) were included in the study, and during 3,038,215 person-years of follow up, a total of 2544 incident cases of colorectal cancer were reported.
The 10-year cumulative incidence of colorectal cancer was 1.98% among regular aspirin users, compared with 2.95% among those who did not use aspirin, where regular aspirin use was defined as two or more standard 325 mg tablets per week. This equated to an absolute risk reduction of 0.97% among aspirin users.
The authors reported that the greatest risk reduction was seen in individuals with the unhealthiest lifestyle scores, and that risk reduction progressively decreased as healthy lifestyle scores increased.
The 10-year absolute risk reduction for the unhealthiest lifestyle scores (0 to 1) was 1.28% compared with 0.11% for the healthiest lifestyle scores (4 to 5).
The 10-year number needed to treat with aspirin was 78 participants with lifestyle scores of 0 to 1, 164 for score 2, 154 for score 3, and 909 for scores 4 to 5.
Additionally, the greatest differences in absolute risk reduction with aspirin use were observed for body mass index and smoking.
Adjunct Professor Graham Newstead, Medical Director of Bowel Cancer Australia, said, ‘One outcome of the study might suggest that GPs consider recommending aspirin for patients who have less healthy lifestyles, but always alongside reinforcing the importance of participating in screening programs and reducing bowel cancer risk through both diet and lifestyle.’
He said that ‘Australian clinical practice guidelines state for all people aged 50 to 70 years who are at average risk of bowel cancer, aspirin should be actively considered to prevent bowel cancer.’
The recommendation is that a low dose (100 to 300mg/day) be used for at least 2.5 years, commencing at age 50 to 70 years.
‘However, there are some risks in taking aspirin which need to be balanced by GPs when making any such recommendation,’ Adjunct Professor Newstead added.