A Prospective Study of Aspirin Use and the Risk for Colorectal Adenoma
- Andrew T. Chan, MD;
- Edward L. Giovannucci, MD, ScD;
- Eva S. Schernhammer, MD, DrPH;
- Graham A. Colditz, MD, DrPH;
- David J. Hunter, MD, ScD;
- Walter C. Willett, MD, DrPH; and
- Charles S. Fuchs, MD, MPH
- From Massachusetts General Hospital, Brigham and Women's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, and Harvard School of Public Health, Boston, Massachusetts.
Abstract
Background: Randomized, double-blind, placebo-controlled trials have established that regular aspirin use reduces the risk for recurrent colorectal adenoma. However, the effect of dose and duration of use, particularly in an average-risk population, is not well understood.
Objective: To examine the influence of dose and duration of aspirin use in the primary prevention of colorectal adenoma.
Design: Prospective cohort study.
Setting: Nurses' Health Study.
Participants: 27 077 women, 34 to 77 years of age, without a history of adenoma, cancer, inflammatory bowel disease, or familial polyposis, who underwent lower endoscopy between 1980 and 1998.
Measurements: 1368 cases of confirmed distal colorectal adenoma were diagnosed between 1980 and 1998. Self-reported data on aspirin use were collected from biennial questionnaires.
Results: After other risk factors for adenoma were adjusted, women who regularly used aspirin (≥ 2 standard aspirin tablets/wk) had a multivariate relative risk for adenoma of 0.75 (95% CI, 0.66 to 0.84) compared with nonregular users. Compared with women who denied any aspirin use, the multivariate relative risks for adenoma were 0.80 (CI, 0.70 to 0.93) for women who used 0.5 to 1.5 standard tablets per week, 0.74 (CI, 0.62 to 0.88) for those who used 2 to 5 tablets per week, 0.72 (CI, 0.61 to 0.85) for those who used 6 to 14 tablets per week, and 0.49 (CI, 0.36 to 0.65) for those who used more than 14 tablets per week (P < 0.001 for trend). Similar dose–response relationships were found among regular short-term users (≤ 5 years; P < 0.001) and long-term users (>5 years; P < 0.001). In contrast, after adjustments were made for dose, increasing duration of aspirin use did not confer greater risk reduction (P > 0.2).
Conclusions: Regular, short-term use of aspirin is inversely associated with risk for colorectal adenoma. However, the greatest protective effect is evident at substantially higher doses (>14 tablets/wk) than those recommended for the prevention of cardiovascular disease. Before aspirin can be recommended for chemoprevention in the general adult population, these results suggest the need for a more thorough evaluation of the risks and benefits of routine aspirin use at doses not previously considered.
Article and Author Information
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Presented in part at the American Gastroenterological Association's Digestive Disease Week, May 2003, Orlando, Florida.
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Acknowledgments: The authors acknowledge the continued dedication of the participants in the Nurses' Health Study and Gideon Aweh, MS, Karen Corsano, MA, and Barbara Egan for assistance.
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Grant Support: By grants HL 34594, CA 87969, and CA 55075 from the National Institutes of Health. Dr. Chan is also supported by grant T32DK07191 from the National Institutes of Health.
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Potential Financial Conflicts of Interest: None disclosed.
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Requests for Single Reprints: Andrew T. Chan, MD, Gastrointestinal Unit, Massachusetts General Hospital, 55 Fruit Street, GRJ-722, Boston, MA 02114.
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Current Author Addresses: Dr. Chan: Gastrointestinal Unit, Massachusetts General Hospital, 55 Fruit Street, GRJ-722, Boston, MA 02114.
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Drs. Giovannucci and Willett: Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115.
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Drs. Schernhammer, Colditz, and Hunter: Channing Laboratory, 181 Longwood Avenue, Boston, MA 02115.
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Dr. Fuchs: Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115.
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Author Contributions: Conception and design: A.T. Chan, E.L. Giovannucci, E.S. Schernhammer, C.S. Fuchs.
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Analysis and interpretation of the data: A.T. Chan, E.L. Giovannucci, E.S. Schernhammer, D.J. Hunter, W.C. Willett, C.S. Fuchs.
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Drafting of the article: A.T. Chan, E.S. Schernhammer, G.A. Colditz, W.C. Willett, C.S. Fuchs.
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Critical revision of the article for important intellectual content: A.T. Chan, E.L. Giovannucci, G.A. Colditz, D.J. Hunter, W.C. Willett, C.S. Fuchs.
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Final approval of the article: A.T. Chan, E.L. Giovannucci, G.A. Colditz, D.J. Hunter, W.C. Willett, C.S. Fuchs.
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Provision of study materials or patients: G.A. Colditz, W.C. Willett, C.S. Fuchs.
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Statistical expertise: A.T. Chan, E.L. Giovannucci, D.J. Hunter, W.C. Willett, C.S. Fuchs.
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Obtaining of funding: E.L. Giovannucci, G.A. Colditz, W.C. Willett, C.S. Fuchs.
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Administrative, technical, or logistic support: C.S. Fuchs.
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Collection and assembly of data: A.T. Chan, E.L. Giovannucci, G.A. Colditz, W.C. Willett, C.S. Fuchs.
- Copyright ©2004 by the American College of Physicians
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