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Does Tylenol Use in Children Cause Asthma?

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This post looks at the scientific evidence of as to whether acetaminophen/Tylenol can cause asthma in light of a new study.
Does acetaminophen cause asthma?  It is one of those “everyone uses this at some point” products. Tylenol, known by its generic name acetaminophen, is a popular pain reliever and fever reducer. It is estimated that 23% of Americans use acetaminophen in any given week. Concerns regarding liver injury have been raised. Other side effects, such as asthma and eczema and autism and ADHD have also recently been gaining notice from scientists and lawyers. The potential risk for asthma when administered to children and used during pregnancy is a concern that was first raised over 10 years ago.
Several studies have suggested that acetaminophen use in pregnancy, infancy, later childhood, and adulthood may be associated with an increased prevalence of asthma. Two extensive observational studies have demonstrated that increased use of acetaminophen in children has occurred due to concerns of Reye’s Syndrome and allergy/asthma to aspirin or other NSAIDs (non-steroidal anti-inflammatory drugs).
How would Tylenol cause autism?  No one knows.  One theory is that acetaminophen may cause an imbalance in the body’s immune system, leading to an increased risk of asthma. Another theory is that acetaminophen may reduce the levels of a natural antioxidant in the body called glutathione, which could increase the risk of asthma.  But there are more questions than answers.

New 2023 Journal of Clinical Medicine Study

A new study published in the Journal of Clinical Medicine in 2023 provides a systematic review and meta-analysis on the effects of prenatal paracetamol exposure on the development of asthma and wheezing in childhood. The study involved 330,550 women and found that maternal exposure to paracetamol during pregnancy was associated with a significant increased risk of asthma and wheeze in their children.

The authors suggest that paracetamol should be used with caution by pregnant women, at the lowest effective dose, and for the shortest duration, and that long-term use or the use of high doses should be limited to the indications recommended by a physician and with the mother-to-be under constant supervision.

Etiminan Study

A meta-analysis (Etminan et al., 2009) examined Tylenol and autism. This systematic review and meta-analysis investigated the potential link between using acetaminophen and the risk of developing asthma in children and adults. The study reviewed and analyzed data from 31 previously published studies, including observational studies and randomized controlled trials, that investigated the association between acetaminophen use and asthma. The studies involved a total of over 1.5 million participants from various countries.

The study’s results suggested that there may be a positive association between the use of acetaminophen and the risk of developing asthma in both children and adults. The analysis showed that people who used acetaminophen had a higher risk of developing asthma than those who did not use it. The risk was exceptionally high among children and those who used acetaminophen frequently or over a long period.

The study suggested that the risk (odds ratio) of acetaminophen-associated asthma is 1.63 in children and adults, and use during pregnancy lead to a risk of 1.28 for asthma and 1.50 for wheezing in children. An odds ratio of 1 means that asthma is likely to occur in both groups (those that used acetaminophen and those that didn’t, equally), and an odds ratio greater than 1 shows that asthma is more likely to occur with acetaminophen use than without.

The study’s author pushed back on its own study in the conclusion, claiming that the overall quality of the evidence was low to moderate and that other factors, such as the severity of the underlying illness, might have influenced the results. Therefore, the study could not establish a definitive causal link between acetaminophen use and asthma.

Pediatrics Study

The study published in the journal “Pediatrics” titled “Acetaminophen use and the risk of asthma in children and adults: a systematic review and meta-analysis” in 2011 aimed to investigate the potential link between the use of acetaminophen (such as Tylenol) in infants and the development of asthma symptoms in early childhood.

The study followed 620 children from birth to age 7 and collected data on their acetaminophen use and respiratory symptoms. The study also collected information on other factors that could affect the risk of developing asthma, such as family history, exposure to secondhand smoke, and birth weight.

The study showed that infants who were given acetaminophen for fever or pain during the first year of life had a higher risk of developing asthma symptoms at age 6 or 7 than those who were not given acetaminophen. Specifically, the study found that infants who were given acetaminophen at least once per year had a 60% higher risk of developing wheezing or asthma symptoms than those who were not given acetaminophen.

Same deal here.  We can all agree that this Canadian study alone does not – and could not – establish a cause-and-effect relationship between acetaminophen use and the risk of developing asthma. It did not prove that acetaminophen causes asthma. But you cannot say the finding don’t suggest at least a possible association between acetaminophen use in infancy and an increased risk of asthma symptoms in early childhood, particularly when looking at the other studies.

Eyers Study

A follow-up study was conducted by Eyers in 2011 to build on these findings. These authors reported a risk for wheezing in children of 1.21 in the offspring of women who used acetaminophen during pregnancy. This study provides further evidence of the relationship between acetaminophen use and asthma and wheezing in children. A study reviewing the use of high-dose acetaminophen found that the risk of asthma more than tripled.

As there are confounding factors that may also lend to the increased prevalence of asthma and respiratory disorders in children, it is interesting to note that many large population-based studies suggest the association of acetaminophen use increases the risk of asthma and wheezing.

Further research is necessary to fully understand the relationship between acetaminophen use and respiratory conditions. I don’t think any lawsuits are imminent. There is still too much that science must do to sort this out.

2013 Lancet Study

The study published in “The Lancet” in 2013 was a large-scale international study that aimed to investigate the potential links between the use of acetaminophen and the development of asthma, eczema, and allergic rhinitis (hay fever) in children.

The study followed a total of 205,487 children from 31 countries, and it collected data on their acetaminophen use and their symptoms of asthma, eczema, and allergic rhinitis at age 6 or 7. The study also considered a wide range of other factors that could affect the risk of developing these conditions, such as family history, smoking during pregnancy, and exposure to environmental pollutants.

The study’s results suggested that children who used acetaminophen for respiratory infections or fever had a higher risk of developing asthma, eczema, and allergic rhinitis by age 6 or 7 compared to those who did not use acetaminophen. Specifically, the study found that children who used acetaminophen at least once per year had a 47% higher risk of developing asthma symptoms, a 35% higher risk of developing eczema, and a 26% higher risk of developing allergic rhinitis, compared to those who did not use acetaminophen.

The study did not establish a cause-and-effect relationship between acetaminophen use and the risk of developing asthma or other conditions. It did not prove that acetaminophen causes asthma. However, the findings suggest a possible association between acetaminophen use and an increased risk of asthma and related conditions.

UCLA Study (2016)

One such study, published in JAMA Pediatrics in 2016, found a positive association between the use of acetaminophen during pregnancy and an increased risk of ASD in offspring. The study found that mothers who reported using acetaminophen during pregnancy had a 30% higher risk of having a child with ASD than those who did not use acetaminophen.

Autism Research Study (2017)

Another study published in the journal “Autism Research” in 2017 – another Canadian that children who had been exposed to acetaminophen in early childhood had a slightly higher risk of developing ASD, compared to those who had not been exposed. The article – titled  “Acetaminophen exposure in pregnancy and early childhood and development of childhood autism spectrum disorder: a systematic review and meta-analysis.” – found that hat children who had been exposed to acetaminophen for more than 28 days had a 20% higher risk of developing ASD, compared to those who had not been exposed. However, this study also could not establish a causal relationship between acetaminophen use and ASD, and more research is needed to confirm the findings.  This might be the weakest finding of the studies we have cited here.

Tylenol and Autism – We Don’t Have Causation Yet

Some evidence suggests that taking acetaminophen, the active ingredient in Tylenol, may be linked to an increased risk of developing asthma. It is probably fair to say that most studies suggest children using acetaminophen is linked to the development of asthma later in childhood.  But it is hardly an article of faith among pediatricians and researchers that there is a connection.  There is a lot of talk about how these studies are designed, which could throw off the results.

Moreover, these studies are observational, which makes causality a steeper climb. More research is needed to determine if there is a causal link between acetaminophen and asthma and to understand the mechanism by which this link may occur.

Should you give your child Tylenol given the possible asthma risk?  The answer is, not surprisingly, it depends.  If you have asthma or are at risk of developing asthma, it is essential to talk to your doctor before taking acetaminophen or any other medication. They can help determine your best course of action based on your health needs and history.

Tylenol Asthma Lawsuits

You would think this page would end with a plug of Tylenol asthma lawsuits. But our law firm is not handling these cases and I’m unaware of any lawyers that are.  First, we are not sure if Tylenol causes autism.  Overall, the evidence on the potential link between acetaminophen use and ASD is still inconclusive. More research is needed to fully understand the potential risks and benefits of using acetaminophen during pregnancy or early childhood.  (Would I bet on it?  I would bet on it.).

But even if we did believe there was a correlation, going from general causation (Tylenol cases asthma) to specific causation (Tylenol caused asthma in that individual child) would be a challenge.