Rich DiPentima spent over 30 years in public health including Assistant Director of Public Health and Chief of communicable disease Epidemiology for the NH Division of Public Health Services, Deputy Public health Officer and chief of Environmental Health for the Manchester Health Department, Director of Health for the Northeast District Dept. of Health (CT) and a Public Health Officer for the Air Force and NH Air National Guard.  He also was a part-time instructor of Epidemiology and Community Medicine and Health Care Policy at the University of NH.

By RICH DiPENTIMA

The Trump administration is now claiming that there is a link between taking acetaminophen during pregnancy and autism spectrum disorder (ASD). Mr. Trump is now advising women not to take acetaminophen during pregnancy. 

Acetaminophen was introduced in the U.S. in the 1950s, sold under various brand names.  It is a very commonly used non-steroid anti-inflammatory (NSAID) and analgesic over-the-counter medication.  In the U.S. approximately 52 million American adults, or 23% of the adult population, including pregnant women use an acetaminophen-containing medicine every week.  Acetaminophen is also the most commonly used over-the-counter medication for pain and fever in children worldwide. It is widely available and used by parents to treat mild to moderate symptoms. 

Autism was first identified by Leo Kanner, an Austrian American psychiatrist in 1943. Kanner described a group of children with similar symptoms, including social withdrawal, communication difficulties, and repetitive behaviors. He coined the term “early infantile autism” to describe these children.

Since first recognized, the prevalence rate for ASD has remained fairly constant at 1 per 1,000 children.  However, since 1995 the prevalence rate has steadily increased to the current rate of 1 in 36 children. 

 Why the large increase? Since the use of acetaminophen has not changed significantly over the years, we would expect that if acetaminophen was the underlying exposure causing ASD we should have seen the increase in the prevalence rate of ASD much earlier.  There are other non-exposure factors that can explain the large increase in ASD prevalence. For example, changes in the case definition for ASD have significantly contributed to the increase in its reported prevalence.

  As diagnostic criteria have broadened, more conditions that were counted separately are now included in the ASD diagnosis.  The changes in the diagnostic criteria have greatly increased the number of individuals diagnosed with ASD.   Since 1980 there have been 4 major changes to the Diagnostic and Statistical Manual of Mental Disorders (DSM) all of which expanded what is considered an individual with ASD.  So what appears on the surface to be a large increase in the number of cases of ASD can be largely explained by the change in the case definition, better understanding and diagnosis by clinicians, and greater public awareness of the condition.

  Another major problem is that the findings reported here are based on what is called an ecological or observational study in epidemiology.  These studies are designed to examine relationships between group-level common exposures and health outcomes.   In this case people with ASD and acetaminophen exposure.  However, such studies are very limited by what is called the ecological fallacy, which prevents them from drawing conclusions about individuals, which is exactly what this supposed relationship between acetaminophen study attempts to do.  

While ASD is a serious problem that impacts the lives of millions, we need to base public health policy on good science.  The most reliable science related to the cause of ASD strongly suggests a genetic relationship. However, interestingly, this new culprit for causing ASD, acetaminophen, is not the vaccines as Mr. Kennedy and Mr. Trump claimed, but a common drug that has been used for over 70 years.  

All drugs including acetaminophen have potential side effects and should be used with caution, especially during pregnancy.  However, considering the limitations of this study and other confounding factors such as the expansion of the case definition, and increased diagnostic awareness, additional studies must be conducted to determine if a causal association between taking acetaminophen during pregnancy and ASD is collaborated by further research before we draw hasty conclusions..  Hopefully, science and not politics will guide future public health policy on this and other matters. 

Rich DiPentima
Portsmouth, NH