Air pollution and autism in Denmark

Abstract

Background: Previous autism spectrum disorder (ASD) and air pollution studies focused on pregnancy exposures, but another vulnerable period is immediate postnatally. Here, we examined early life exposures to air pollution from the pre- to the postnatal period and ASD/ASD subtypes in the Danish population. Methods: With Danish registers, we conducted a nationwide case-control study of 15,387 children with ASD born 1989–2013 and 68,139 population controls matched by birth year and sex identified from the birth registry. We generated air dispersion model (AirGIS) estimates for NO2, SO2, PM2.5 and PM10 at mothers’ home from 9 months before to 9 months after pregnancy and calculated odds ratios (OR) and 95% confidence intervals (CI), adjusting for parental age, neighborhood socio-economic indicators, and maternal smoking using conditional logistic regression. Results: In models that included all exposure periods, we estimated adjusted ORs for ASD per interquartile range (IQR) increase for 9 month after pregnancy with NO2 of 1.08 (95% CI: 1.01, 1.15) and with PM2.5 of 1.06 (95% CI: 1.01, 1.11); associations were smaller for PM10 (1.04; 95% CI: 1.00, 1.09) and strongest for SO2 (1.21; 95% CI: 1.13, 1.29). Also, associations for pollutants were stronger in more recent years (2000–2013) and in larger cities compared with provincial towns/rural counties. For particles and NO2, associations were only specific to autism and Asperger diagnoses. Conclusion: Our data suggest that air pollutant exposure in early infancy but not during pregnancy increases the risk of being diagnosed with autism and Asperger among children born in Denmark.

The association between particulate matter 2.5 exposure and children with autism spectrum disorder

“…One study indicated that both prenatal and postnatal exposures to PM 2.5 are associated with increased risk of ASD (Talbott et al, 2015), while another study found that higher maternal exposure to PM 2.5 during pregnancy, particularly the third trimester, was associated with greater odds of a child having ASD (Raz et al, 2015). On the contrary, one study suggested that air pollutant exposure in early infancy but not during pregnancy increases the risk of being diagnosed with autism and Asperger among children born in Denmark (Ritz et al, 2018). In this study, we found that elevated exposures to PM 2.5 during the first three years of life were associated with the increased risk of ASD and severe ASD in a Chinese cohort.…”

Ambient Air Pollution Increases the Risk of Cerebrovascular and Neuropsychiatric Disorders through Induction of Inflammation and Oxidative Stress

“…Increased risk of autism spectrum disorders in response to maternal exposure to air pollution was also found in a recent study in Sweden indicating an OR of 1.40 (95% CI 1.02–1.93) with increased NO x exposure (top quartile), whereas no substantial associations were found for the risk of developing attention deficit hyperactivity disorder [ 99 ]. Moreover, there are data from Denmark showing that air pollution exposure in early infancy but not during pregnancy increases the risk of being diagnosed with autism and spectrum disorder [ 100 ]. This was confirmed by an Israeli study resulting in higher odds for postnatal exposure to NO 2 and autism risk than for prenatal exposure [ 101 ].…”

Impact of Environmental Injustice on Children’s Health—Interaction between Air Pollution and Socioeconomic Status

“…Air pollution might also affect children’s mental health. Exposure to air pollution during infancy [ 36 ] and prenatal stages [ 37 ] has been associated with autism spectrum disorder (ASD) and long-term exposure to air pollution during childhood has been associated with an increased risk of developing attention-deficit/hyperactivity disorder (ADHD) [ 38 , 39 ] and depression [ 8 ].…”