Several key studies have examined autism rates in Amish communities. One early study in Pennsylvania by a research group from Johns Hopkins University found only 3 cases of autism out of almost 10,000 Amish children surveyed. This suggested an autism rate of only around 1 in 3,000, compared to around 1 in 150 for the general US population at the time.
A follow-up study by the same group looked at almost 16,000 Amish children in Indiana and found only 11 cases of autism. This suggested a rate of around 1 in 1,500, still far below the broader population.
There are limitations to these studies. They relied on educational and medical records rather than direct clinical assessments. Some milder cases may have been missed. Plus, the cultural attitudes of the Amish may mean a reluctance to seek a diagnosis.
More recent studies have attempted to directly screen and diagnose Amish children. A 2016 study assessed almost 300 Amish children in Ohio and found 4 cases of autism – a rate of around 1 in 75. This suggests the rates may not be as low as initially thought, but still below the general population.
Who are the Amish?
The Amish are a traditional Christian group that largely shuns modern technology and lives a simple, rural lifestyle. There are several settlements of Amish communities, mostly located in Pennsylvania, Ohio, and Indiana. The Amish have limited contact with mainstream American culture and avoid many features of modern life, such as electricity, cars, and television. This separation provides a unique opportunity for researchers to study potential links between autism and modern societal factors.
Autism Prevalence
Autism spectrum disorder (ASD) refers to a range of conditions characterized by challenges with social skills, repetitive behaviors, speech, and nonverbal communication. In recent decades, autism diagnoses have increased dramatically in many countries around the world. For example, data from the Centers for Disease Control and Prevention (CDC) indicates that around 1 in 44 children has been identified with ASD as of 2020.
There are several potential reasons proposed for the rise in autism rates:
- Expanded diagnostic criteria – The definition and diagnostic criteria for autism have evolved to include a broader range of symptoms and presentations. As a result, more individuals qualify for a diagnosis today.
- Increased awareness and screening – There is a greater public understanding of autism, leading to more children being evaluated and identified. Pediatricians are also screening for autism more frequently.
- Diagnostic substitution – Some of the increase may be due to children who would previously have been diagnosed with intellectual disability or other conditions now being classified under autism spectrum disorder instead.
- Unknown environmental factors – Some experts believe unknown environmental influences could play a role in rising autism rates, but no specific factors have been definitively identified. More research is needed in this area.
While the increase in autism diagnoses is well documented, there is debate about how much of this reflects a true increase versus improved identification and awareness. Determining the actual prevalence continues to be an active area of study.
The Amish Community
The Amish are a group of traditionalist Christians that form closed communities across North America but are concentrated mostly in Pennsylvania, Ohio, and Indiana. There are about 350,000 Amish living in these communities in the United States and Canada.
The Amish live a simple life disconnected from modern conveniences and technology. They dress plainly, usually in dark colors. The men wear beards and pants with buttons instead of zippers. The women wear bonnets and long dresses. The Amish speak Pennsylvania Dutch, a dialect of German, among themselves.
The Amish follow a strict code of conduct called the Ordnung that governs everything in their daily lives, including prohibitions on using electricity, automobiles, telephones, and more. They rely on horse-drawn buggies for transportation. Their homes lack modern amenities like electricity. Most Amish do not attend high school, feeling that their traditional education is sufficient. The Amish value rural life, manual labor, and humility, shunning many aspects of modern life.
This separation from mainstream culture and limited use of technology means the Amish live much differently than most 21st-century Americans. Their isolated, low-tech lifestyle provides an interesting contrast to examine factors that may influence rates of autism.
Potential Factors in Autism
Autism is a complex neurodevelopmental condition with many contributing factors. Researchers have proposed numerous genetic and environmental influences that may lead to autism spectrum disorder (ASD).
Some of the main genetic factors believed to play a role include:
- Rare mutations and copy number variations – Changes or deletions in certain genes and chromosomes have been associated with increased autism risk. However, most genetic changes linked to autism are unique or rare.
- Common genetic variants – Certain common gene variants may slightly increase autism susceptibility, especially when combined. Autism likely involves a complex combination of many common genetic differences rather than one single cause.
- Heritability – Identical twins have a higher concordance rate of autism than fraternal twins, indicating strong genetic components. If one identical twin has autism, the other has a 70-90% chance of also being affected.
Some key environmental factors that have been hypothesized to contribute to autism include:
- Advanced parental age – Children born to older parents may have increased autism risk, perhaps due to greater chances of genetic mutations.
- Prenatal/perinatal complications – Certain pregnancy and birth complications have been associated with higher autism rates, such as maternal infections, prematurity, fetal distress, or chemical exposures.
- Environmental toxins – Exposure to pollutants like air pollution, pesticides, or heavy metals may potentially impact autism risk, especially during critical developmental windows.
- Lifestyle factors – Various social, dietary, chemical, and behavioral factors may interact with genetic susceptibilities to influence autism development.
However, most cases of autism likely result from a complex interplay between genetic predispositions and environmental influences. More research is needed to fully understand the contributions of different factors to autism spectrum disorders.
Explanations for Lower Autism Rates
Several potential factors may contribute to lower autism rates among Amish children compared to the general population:
- Genetic isolation – The Amish population descended from a small group of founders and has remained genetically isolated. This isolation and smaller founding gene pool means certain genetic mutations linked to autism may be less common.
- Lifestyle differences – The traditional Amish lifestyle lacks many features of modern life that some believe may be risk factors for autism, like advanced paternal age, prenatal medication use, and exposure to pollutants. The Amish also have large families and a rural upbringing, which could provide increased socialization.
- Underdiagnosis – Autism may be underdiagnosed among Amish children due to less access to healthcare services, a lack of awareness of autism, and cultural stigma around disabilities and mental health issues. Some milder cases of autism may go undetected.
- Reporting differences – Most autism prevalence estimates for the general population rely on education and medical records. These formal reporting channels capture fewer Amish children, so comparing them to general population rates may not be accurate.
More research is needed to fully explain the lower observed autism rates among the Amish. However their genetic history and traditional lifestyle offer clues about factors that may contribute to autism risk. Understanding these potential protective factors could provide important insights.
Modern Lifestyle Factors
While the Amish community lives a more traditional lifestyle, the modern world has introduced various factors that may increase autism risk. Some key aspects of modern life potentially linked to higher autism rates include:
- Increased exposure to chemicals and pollutants – Studies show links between environmental toxins and autism, with evidence that chemicals can impact brain development. The modern world has introduced more man-made chemicals into our environment.
- Higher maternal and paternal age – Research indicates increased autism risk in children born to older parents. Modern trends like delayed parenthood may play a role.
- Diet and nutrition – Diets high in processed foods and lacking key nutrients may negatively impact brain development. The modern food system differs greatly from traditional diets.
- Reduced gut microbiome diversity – The “Western diet” and overuse of antibiotics may deplete healthy gut bacteria tied to brain health. Traditional diets maintain more microbial diversity.
- Increased use of infant formula – Breastfeeding supports healthy gut flora, immune function, and brain development. Formula feeding is now common, while extended breastfeeding was the norm.
- More prenatal and perinatal complications – Issues like preeclampsia and low birth weight are associated with higher autism rates and are more common today.
- Higher rates of cesarean sections – C-sections impact microbiome development and may increase autism risk. Cesarean rates are much higher now than in past eras.
- Less natural childbirth and bonding – Interventions in the birthing process potentially disrupt bonding hormones and brain development. The modern experience often lacks traditional birthing practices.
The Amish Lifestyle and Autism
The Amish traditional lifestyle and culture may limit exposure to some factors associated with increased autism risk. Here are some key ways the Amish lifestyle differs from modern mainstream culture:
- Less exposure to air pollution – The Amish have limited vehicle use and industrial exposure. Air pollution has been linked to increased autism risk.
- Natural diet – The Amish eat homegrown and homemade foods, avoiding processed items. Their diet is rich in immune-boosting and anti-inflammatory foods. Diet and nutrition impact brain development.
- Tight-knit community – The Amish live communally with strong social connections. Social interaction shapes early brain development. Isolation is a risk factor.
- Natural childbirth – Amish women often give birth at home without drugs. Interventions in childbirth may alter development.
- Farm life – Amish children grow up exposed to microbes from animals and soil. This helps build immunity and gut health. The “hygiene hypothesis” links low microbial exposure to immune dysfunction.
- No vaccines – The Amish vaccinate less often. Though evidence does not support vaccines causing autism, some argue that reduced vaccination avoids neuroimmune risks in sensitive children.
While more research is needed, these lifestyle factors likely contribute to the lower observed autism rates among the Amish. Their traditional lifestyle avoids many modern exposures associated with impaired neurological development.
