Monthly Archives: January 2016

Air Pollution and Autism

Air Pollution Exposure during Pregnancy and Childhood Autistic Traits in Four European Population-Based Cohorts Studies: The ESCAPE Project

Environ Health Perspect;  Guxen et al. 2016 January Issue 1. DOI:10.1289/ehp.1408483

Dr. Kathy’s review of the recent publication.

Air quality is of great concern for many reasons. Poor air quality, for example has been associated with an increased incidence of heart attacks, asthma exacerbations and autism spectrum disorders (especially in children living close to a large highways).

The study listed above was recently published in Environmental Health Perspectives and is free and available on line for our review (See link below).

This study lends controversy to some of the thoughts on air pollution and it’s effect on neurodevelopment.

In this study 8,079 children were included. Maternal exposure to air pollution was determined by nitrogen oxide levels and particulate matter absorbance in four European countries (Sweden, Italy, Spain and Netherlands)

Levels were extrapolated to the exact time of pregnancy and children between the ages of 4-10 years of age were assessed for autistic traits or true clinical autism based on four different autism testing scales.

Interestingly, the highest rates of autism and autistic traits were found mostly in boys with a higher proportion of moms with low education levels and who smoked compared to children without autistic traits.

There was no statistical difference in rates of autism or autism traits in relation to airborne particle matter and nitrogen oxide levels in this European study.

In comparison, several studies performed in Los Angeles California showed a positive association between air pollution levels and autism spectrum disorders during the prenatal time period.

Why the difference? Many possibilities exist including the following; the age range of children in the California studies was 2-6 years old as opposed to 4-10 years old, the air pollution levels including particulate matter and the nitrogen oxide levels were also higher in California than the European study. Finally we could be dealing with many other confounding environmental and perhaps genetic variables that are contributing to this finding.

What is the take home point? According to the article, there have been studies published that strongly demonstrate that animals exposed to urban pollutants have an increase in brain toxicity.

The increased incidence of autism is seen not just in the United States where the rates are 1 in 68 but also in Europe, where in 2007 the rates were 1 in 86. In the United States data, there is a strong association between autism and air pollution. Further investigation comparing differences between the European and United States studies would be of benefit to explain the opposing outcomes.

Prudence tells us to keep our environment clean, as this study reiterates, avoid smoking during pregnancy and limit toxic exposures. The study presented in this article is conflicting but the obvious elephant in the room is that the prevalence of autism is increasing and will be an ever-larger burden on our society if preventative and investigative measures are not taken.

The true cause of autism is not known, however, it is felt to be a combination of genetic propensity combined with environmental factors, such as diet, toxic exposures, infections and perhaps air pollution. I encourage you to read the article below.