Aspirin and Decreased Adult-Onset Asthma


RATIONALE: In an observational cohort study, women who self-selected for frequent aspirin use developed less newly diagnosed asthma than women who did not take aspirin.

OBJECTIVE: To explore whether low-dose aspirin decreased the risk of newly diagnosed asthma in a randomized double-blind, placebo-controlled trial.

METHODS: The Physicians' Health Study randomized 22,071 apparently healthy male physicians, age 40-84 years at baseline and tolerant of aspirin over an 18-week run-in period, to 325mg aspirin or placebo on alternate days. The aspirin component was terminated after 4.9 years due principally to the emergence of a statistically extreme 44% reduction in risk of first myocardial infarction among those randomly assigned to aspirin.

RESULTS: Among 22,040 physicians without reported asthma at randomization, there were 113 new asthma diagnoses in the aspirin and 145 in the placebo group. The hazard ratio was 0.78 (95% confidence interval, 0.61 to 1.00; P=0.045). This apparent 22% lower risk of newly diagnosed asthma among those assigned to aspirin was not modified by baseline characteristics including smoking, body mass index, or age.

CONCLUSIONS: Aspirin reduced the risk of newly diagnosed adult-onset asthma in a large randomized clinical trial of apparently healthy, aspirin-tolerant men. This result requires replication in randomized trials designed a priori to test this hypothesis; it does not imply that aspirin improves symptoms in patients with asthma.