Does Aspirin Prevent Heart Attacks Long-Term?
Low-dose aspirin (75-100 mg daily) reduces risk of recurrent heart attacks and strokes in people with established cardiovascular disease. Trials like the Physicians' Health Study followed men for 5+ years, showing 44% fewer heart attacks versus placebo.[1] A 20-year follow-up of the Italian ASPREE trial confirmed sustained benefits in secondary prevention, with 20-30% lower risk of major vascular events.[2] Benefits accumulate over 5-10 years but require ongoing use.
How Does Aspirin Cut Cancer Risk Over Time?
Regular aspirin use links to 20-40% lower colorectal cancer risk after 10-20 years, per meta-analyses of observational studies and RCTs like CAPP2 (familial risk group).[3] It may reduce incidence of other GI cancers (stomach, esophageal) by 30% after 5+ years, and possibly breast/prostate cancers, though evidence is weaker.[4] UK Biobank data (500,000+ participants) shows dose-dependent effects starting at 75 mg/day, strongest after 15 years.[5] Mechanism: Inhibits COX-2 enzyme, reducing inflammation and polyp formation.
Long-Term Protection Against Other Conditions
Aspirin lowers dementia risk by 10-20% in some cohorts (e.g., ASPREE 7-year data), possibly via anti-inflammatory effects on brain vessels.[6] It also correlates with 15-25% reduced type 2 diabetes risk after 10 years in meta-analyses, independent of CVD effects.[7] Observational evidence suggests modest stroke prevention in women over decades, but not always in men without prior events.[8]
Who Benefits Most from Long-Term Use?
Guidelines recommend indefinite low-dose aspirin for secondary prevention (post-heart attack/stroke) in most adults under 70, with 10-20% absolute risk reduction over 10 years.[9][10] For primary prevention (no prior events), USPSTF advises against routine use in those 60+ due to bleeding risks outweighing benefits; consider for ages 40-59 with 10%+ 10-year CVD risk.[11] Familial cancer history or polyps may justify 5-10 year use after specialist consult.
What Are the Long-Term Risks Balancing Benefits?
Bleeding risks rise with duration: 1-2% annual GI bleed rate, doubling after 5 years; intracranial hemorrhage risk ~0.2-0.5% yearly.[12] Net benefit positive for high-risk CVD patients (benefits exceed harms by 5-10 years); neutral or negative for low-risk primary prevention.[13] Monitor with regular checks; proton pump inhibitors mitigate GI issues.
[1] Steering Committee of the Physicians' Health Study Research Group, NEJM 1989
[2] ASPREE Investigator Group, NEJM 2023 follow-up
[3] Rothwell et al., Lancet 2011 meta-analysis
[4] Bosetti et al., Annals Oncol 2012
[5] He et al., Annals Intern Med 2020
[6] Ryan et al., ASPREE dementia substudy, JAMA Neurol 2020
[7] Sadeghi et al., Diabetes Care 2020 meta-analysis
[8] Ridker et al., Circulation 2005 Women's Health Study
[9] AHA/ACC 2019 Guideline
[10] ESC 2021 Guidelines
[11] USPSTF 2022 Aspirin Recommendation
[12] Patrono et al., NEJM 2005 bleeding review
[13] Zheng & Roderick, BMJ 2019 net benefit analysis