The cause of autism spectrum disorders (ASD) is a mystery. Research has shown that it is, in part, genetic. But genetics alone doesn’t explain who gets autism. It is believed that genetics make some people more at risk of developing ASD but that environmental factors also play a role. When scientists use the term environmental factors, they refer to anything non-genetic. This can be exposure to toxins such as pollutants and chemicals or could be the age of the parents at conception, birth complications or having an infection during pregnancy. All of these factors have been shown to have a link to the risk of developing ASD.
A number of studies have focused on pollutants and chemicals, such as pesticides. Although a link has been shown between these types of environmental factors, many experts believe a child must be predisposed, through genetics, to ASD. This combination, then, would be the cause. A new study, released in March, 2014, claims to strengthen this link. According to the study, prenatal exposure to pollutants significantly increased the risk of autism.
Scientists looked at over 100 million insurance claims from around the country. They found that ASD and other intellectual disabilities occurred more significantly in some areas of the country than in others. They found that this disparity could be found even in different counties. In order to compare the rates of autism to the level of pollutants in the area, the researchers looked at male genital malformations or birth defects. According to the researchers, “accumulating evidence suggests that the rate of birth malformations (of the reproductive system)…could serve as an indicator of parental exposure to toxins.”
The researchers found a direct correlation to the number of genital birth defects and the rate of autism. The study found that for each percent increase of genital birth defects, there was a 283 percent increase in autism diagnoses. The authors conclude that the study supports the theory that exposure to pollutants during pregnancy contributes to developing ASD.
The results of this study were reported by many different news organizations, including Time.com. However, not everyone agrees with the results. Emily Willingham, a contributor for Forbes Magazine, has several concerns with the study. A few of her concerns are:
- Male genital malformations and birth defects are not an adequate measure of environmental pollutants and toxins. She explains that these birth defects can be caused by numerous factors, including low birth weight, premature birth, intra-uterine growth restriction and genetics. The presence of these birth defects alone cannot be enough to indicate there are environmental toxins.
- Insurance claims along don’t give a full picture of the health of an area, including the incidence of diseases and conditions. Those with health insurance have more access to health care and also are more financially stable than those without health insurance. These factors skew the results, giving a picture of those who are more likely to have their child diagnosed because of access.
- Risk factors for male genital malformations include low birth weight and premature birth. These are also considered risk factors for ASD.
- The research study found that male children with autism are more likely to have a congenital genital malformation, which when together would point to a genetic cause rather than an environmental one.
According to Willingham, the common denominator isn’t pollutants or toxins, it is genetics.
Published On: March 24, 2014