Who are the stellar authors?
Anna Oudin, Kasper Frondelius, Nils Haglun, Karin Källén, Bertil Forsberg, Peik Gustafsson, Ebba Malmqvist,
What is the study about?
This study investigates the possible correlation between exposure to air pollution during pregnancy and the likelihood of developing autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD).
The research analyzed data from an epidemiological database in Southern Sweden that included over 48,000 children born between 1999 and 2009.
Findings showed that even exposure to air pollution levels below the current WHO guidelines was associated with a higher risk of developing ASD, but not ADHD. This study adds to the mounting evidence linking air pollution exposure to ASD and calls for additional research in this field.
What previous research is there on this topic?
According to the latest research, there are ten studies from the USA that have found a link between air pollution and an increased risk of autism. Similar findings have been reported by one study each in Israel and Taiwan.
However, one study conducted in Stockholm, Sweden, did not find an effect when using clinical diagnoses. Additionally, one cohort study from the Netherlands found no evidence of a connection between air pollution exposure and ASD. A study from Denmark also reported no significant association between air pollution exposure during pregnancy and ASD or ADHD.
What methods were used in this study?
The study investigated the impact of air pollution exposure on the risk of autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD) using data from a large Swedish epidemiological database called MAPSS. The database covered 99% of all children born between 1999 and 2009 in the study area in southern Sweden.
The study focused on nitrogen oxides (NOx), a common traffic-related air pollutant, and used a computer model to estimate exposure levels based on factors like vehicle type, speed, and traffic volume, as well as other sources of NOx.
The researchers mapped the NOx concentration levels at the homes of study participants by using their residential address and divided the levels into quartiles for analysis. It’s worth noting that the study only examined NOx exposure at home and did not account for exposure during other activities such as commuting or work.
The findings contribute to the growing body of evidence linking air pollution exposure during pregnancy to an increased risk of ASD.

What were the findings?
The study provides evidence of a potential link between prenatal exposure to air pollution and Autism Spectrum Disorder (ASD) development. According to the findings, prenatal air pollution exposure was positively associated with an increased risk of developing ASD.
However, there was no such correlation found between air pollution and Attention-Deficit/Hyperactivity Disorder (ADHD) risk.
These findings add to the mounting evidence that even air pollution exposure below current WHO guidelines may contribute to ASD development. Nonetheless, further research is necessary to fully comprehend the effect of air pollution on ADHD development.
What were the limitations of the study?
The study has several limitations to consider. Firstly, the study only measured exposure to air pollution at each participant’s home residence, without considering exposure during commuting or at work. This limitation may affect the accuracy of the air pollution exposure estimates.

Secondly, the study’s findings may not be generalizable to other areas in Sweden or other countries with different sources of air pollution, due to the limited geographical region and environmental database used.
Thirdly, maternal behavior during pregnancy and socioeconomic status could be possible confounders that were not fully accounted for in the analyses.
Fourthly, the study relied on diagnostic measures for ASD and ADHD, which might not fully capture the range of symptoms and impairments in children with these disorders.
Lastly, the study did not consider other environmental factors that the children may have been exposed to, such as pesticides or chemical pollutants, that could be involved in the development of ADHD or ASD.
What other areas of research does this study connect to?
Numerous studies have shown a link between air pollution exposure and neuro-inflammation. One study revealed that pregnant women exposed to air pollution had increased systemic and neuro-inflammation.
Neuro-inflammation can contribute to neurological disorders, including autism spectrum disorder (ASD). Additionally, air pollution exposure has been linked to imbalances in brain function and the breakdown of the blood-brain barrier in children.
These findings suggest that air pollution may affect the central nervous system through neuro-inflammation and neurotoxicity, leading to developmental neurotoxicity and ASD.
Can I read the full study somewhere?
Of course you can beautiful. Right here.