Investigations conducted by the International Study of Allergy and Asthma in Childhood over the past 30 years document a strong relationship between acetaminophen use and the development of asthma in children, in addition to a possible association with allergic rhinoconjunctivitis and eczema.
The relationship was so strong, in fact, that the epidemic of emerging childhood asthma cases affecting the world’s most developed countries is now thought to be a result of increased acetaminophen use in the countries affected. Although the causal association acetaminophen is still hotly debated among many medical professionals, the well-established link between the drug and asthma occurrences has resulted in a significant shift in thought among general practitioners. Instead of acetaminophen, doctors are now instructing parents to use alternatives like ibuprofen to treat fevers and pain in their children, if they have to use a drug at all.
When the human body metabolizes acetaminophen, a reaction occurs that leads to a depletion in airway mucosal glutathione, an important antioxidant. Dr. John T. McBride, MD at the Department of Pediatrics, Northeast Ohio University, and at the Department of Pediatrics, Akron Children’s Hospital, believes that this depletion may also be a contributing factor in oxidative stress – the same oxidative stress that studies have linked with Atherosclerosis, Parkinson’s Disease, myocardial infarction, heart failure, Alzheimer’s disease, fragile X syndrome, and chronic fatigue syndrome. Whether this depletion is also the key ingredient that leads to childhood asthma is still in question, but the relationship is strongly suspected.
No matter the specific component of causation, study results outline a very clear relationship between using acetaminophen and developing asthma. One such double-blind comparison study comparing ibuprofen to acetaminophen showed no link with ibuprofen, whereas acetaminophen was found to increase the risk for asthma 1.61-fold in children ages 6-7 who took it more than once per year, and 3.23-fold if they took it least once per month (95% confidence for both studies). It is interesting to note that in nearly all of the studies performed, acetaminophen was singled out as the cause regardless of age, race, gender, geographic location, or economic station.
In addition to noting the increase in childhood asthma cases, investigators have determined that if acetaminophen use was discontinued altogether, there would be a 38% reduction in asthma related symptoms relating to acetaminophen in the entire population of 6-7 year-old children. By the same measure, current wheezing would be lessened by 41% in 13-14 year-olds, and severe asthma symptoms would be reduced by 43%.
Just over a decade ago, the same relationship was established between acetaminophen use and asthma in adults. A large number of studies were also conducted to make this determination, many of which were verified to be using extremely strict controls to ensure accuracy of the results. These studies showed an average of a 1.71-fold increase in asthma in adults using acetaminophen, including a 2.87-fold increase in adults using acetaminophen at least once per week – this association was not found in any of the other analgesics studied by these investigators.
An analysis of the third National Health and Nutrition Examination Survey conducted in the United States also showed a dose-response relationship between acetaminophen and Chronic Obstructive Pulmonary Disease and asthma in adults, in addition to decreased lung function directly proportional to increased acetaminophen dosage. However, it should be noted that some significantly smaller studies (less than 100 participants) showed a similar association for non-steroidal anti-inflammatory drugs.
Although acetaminophen is still free of all charges as a direct cause of childhood asthma – this conviction will likely require many years of further study, in addition to fighting the “muddying” of the waters that so often occurs when prevalently used consumer products are concerned – it is certainly a very strong suspect. Strong enough to warrant Pediatric specialists like Dr. McBride steering patients away from the popular drug.
If you have ever struggled with lung problems such as asthma, chronic obstructive pulmonary disease, or decreased lung function – or if you know someone with any of these problems – the safe move would certainly be to switch to an alternative like ibuprofen if possible, or even stop taking analgesics altogether where circumstances allow. Consult your doctor regarding prescription alternatives that don’t contain acetaminophen, and never remove yourself from a current prescription without first seeking professional medical advice.
Official Journal of the American Acadamy of Pediatrics: The Association of Acetaminophen and Asthma Prevalence and Severity
American Journal of Respiratory and Critical Care Medicine