A prospective study of aspirin use and the risk of pancreatic cancer in women.
BACKGROUND
In vitro experiments and limited animal studies suggest that aspirin and nonsteroidal anti-inflammatory drugs may inhibit pancreatic carcinogenesis. Because few studies have examined the association between aspirin use and pancreatic cancer in humans and the results have been inconsistent, we examined the relationship between aspirin use and the development of pancreatic cancer in the Nurses' Health Study.


METHODS
Among 88 378 women without cancer at baseline, we documented 161 cases of pancreatic cancer during 18 years of follow-up. Aspirin use was first assessed at baseline in 1980 and updated biennially thereafter. All statistical tests were two-sided.


RESULTS
Participants were classified according to history of aspirin use. In a multivariable analysis, the risk of pancreatic cancer was not associated with current regular aspirin use (defined as two or more standard tablets per week; relative risk [RR] = 1.20, 95% confidence interval [CI] = 0.87 to 1.65), compared with use of fewer than two tablets per week. Increasing duration of regular aspirin use, compared with non-use, was associated with a statistically significant increase in risk: Women who reported more than 20 years of regular aspirin use had an increased risk of pancreatic cancer (RR = 1.58, 95% CI = 1.03 to 2.43; P(trend) =.01). Among women who reported aspirin use on at least two of three consecutive biennial questionnaires compared with consistent non-users of aspirin, the risk increased with dose (one to three tablets per week: RR = 1.11, 95% CI = 0.70 to 1.76; four to six tablets per week: RR = 1.29, 95% CI = 0.70 to 2.40; seven to 13 tablets per week: RR = 1.41, 95% CI = 0.76 to 2.61; and > or = 14 tablets per week: RR = 1.86, 95% CI = 1.03 to 3.35) (P(trend) =.02).


CONCLUSIONS
Extended periods of regular aspirin use appear to be associated with a statistically significantly increased risk of pancreatic cancer among women.
Schernhammer
Eva S
ES
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA. eva.schernhammer@channing.harvard.edu
Kang
Jae-Hee
JH
Chan
Andrew T
AT
Michaud
Dominique S
DS
Skinner
Halcyon G
HG
Giovannucci
Edward
E
Colditz
Graham A
GA
Fuchs
Charles S
CS
D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000009:adverse effects*; D001241:Aspirin / Q000008:administration & dosage / Q000009:adverse effects*; D004363:Drug Utilization / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D009726:Nurses / Q000706:statistics & numerical data; D016017:Odds Ratio; D010190:Pancreatic Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D011446:Prospective Studies; D012107:Research Design; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D014481:United States / Q000453:epidemiology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin