Aspirin may reduce the risk of newly diagnosed adult-onset asthma

A post-hoc analysis of the large, randomized, double-blind, placebo-controlled Physicians' Health Study found that the use of low-dose aspirin (ASA) on alternating days reduced the risk of adult-onset asthma by a statistically significant 22%.

These results were published in the American Journal of Respiratory and Critical Care Medicine.

The Physicians' Health Study was a 2×2 factorial trial of 325 mg ASA and 50 mg beta-carotene for the primary prevention of cardiovascular disease and cancer among 22,071 male physicians aged 40 to 84 years. Participants were excluded from the trial if they had a previous diagnosis of myocardial infarction, stroke, transient ischemic attack, cancer, current renal or liver disease, peptic ulcer, or gout, or if they reported the current use of ASA, vitamin A, or beta-carotene supplements. The trial was terminated early after an average of 4.9 years of follow-up due to a demonstrated 44% reduction in the risk of a first myocardial infarction in participants receiving ASA. A change in the risk for asthma was not an a priori end point of the trial.

The authors suggested that ASA likely reduced the risk of developing asthma through its inhibition of various products of the arachidonic acid pathway known to cause airway hyper-responsiveness and pulmonary inflammation.

These results from the Physicians' Health Study are consistent with prior findings from the Nurses' Health Study, which examined a large group of female registered nurses who frequently used ASA for pain control and were found to have a lower incidence of newly diagnosed asthma compared with those who never used aspirin (P=.03).

The authors said the design of the Physicians' Health Study, the likelihood of accurately reported new diagnoses of asthma, and the levels of follow-up and compliance were among the study's assets. In addition, they noted that their trial had adequate size to detect a small-to-moderate benefit of ASA on newly diagnosed adult-onset asthma even though this trial was not originally designed to test this hypothesis. Although the trial suggested that ASA might reduce the risk of asthma in adults by 22% compared with placebo, the authors emphasized that additional randomized trials would help to validate their research.

SOURCES Barr RG, Kurth T, Stampfer MJ, Buring JE, Hennekens CH, Gaziano JM. Aspirin and decreased adult-onset asthma: Randomized comparisons from the Physicians' Health Study. Am J Resp Crit Care Med. 2007;175:120–125.

Barr RG, Wentowski CC, Curhan GC, et al. Prospective study of acetaminophen use and newly diagnosed asthma among women. Am J Resp Crit Care Med. 2004;169:836–841.