In a systematic review of the literature and meta-analysis, researchers found that acetaminophen use is associated with an increased risk of asthma and wheezing in both children and adults.
A study reported in the November 2009 issue of Chest assessed the effect of acetaminophen use on asthma diagnosis. The researchers searched for articles from MEDLINE and EMBASE and ultimately assessed 13 cross-sectional studies, 4 cohort studies, and 2 case-control studies involving a total of 425,140 patients. Nine of the studies assessed the risk of asthma in both children and adults, 6 assessed wheezing in children, and 5 evaluated prenatal exposure to acetaminophen and its association with wheezing in children. Across the studies, the odds ratio (OR) for asthma among all acetaminophen users was 1.63 (95% confidence interval [CI], 1.46-1.77). Among children, the OR for asthma was 1.60 (95% CI, 1.48-1.74) for those who used acetaminophen in the year before asthma diagnosis and 1.47 (95% CI, 1.36-1.56) for those treated with acetaminophen during the first year of life. The OR for wheezing in children was 1.97 (95% CI, 1.51-2.56) for those who used acetaminophen in the year before diagnosis and 1.51 (95% CI, 1.24-1.83) for those treated with acetaminophen during the first year of life. Additionally, prenatal acetaminophen use was associated with an OR of 1.28 (95% CI, 1.13-1.39) for asthma and 1.50 (95% CI, 1.10-2.05) for wheezing. In the 1 study that assessed high-dose acetaminophen use in children, this treatment was associated with an OR of 3.23 for asthma (95% CI, 2.9-3.6).
Considering the widespread use of acetaminophen, the authors suggested that further studies should be carried out to more closely examine this potential association between acetaminophen and asthma.