Table 4.
Studies investigating the association between exposure to SO2 and ASD development.
Authors and Year | Study Design | Sample Size/Country | ASD Outcome Assessment | Exposure Assessment | Method of Analysis | Adjustment Variables | Time Window of Exposure | Main Findings |
---|---|---|---|---|---|---|---|---|
Ritz et al., 2018 [26] |
Case-control | 15,387 ASD cases and 68,139 controls from Denmark | ASD diagnosis according to International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) | Exposures estimates provided by the dispersion models (AirGIS) for the detected pollutants (NO2, SO2, PM2.5 and PM10) in relation to the maternal residence during the examined periods | Conditional logistic regression | -parental age -neighborhood -socio-economic indicators -maternal smoking |
-pregnancy -9 months after pregnancy |
The authors estimated an OR of 1.21 (95%CI: 1.13, 1.29) for ASD onset per each increase of 2.8 μg/m3 SO2 in IQR value, 9 months after pregnancy |
Yousefian et al., 2018 [36] |
Case-Control | 134 ASD cases and 388 controls from Tehran, Iran | The diagnosis of ASD was based on the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-R) | Land-use regression models were used to estimate their annual mean exposure to ambient PM10 | Logistic regression | -maternal age at birth -maternal education -paternal education -cousin marriage -maternal smoking during pregnancy -birth order -gestational age (weeks) -multiple births -maternal disease -paternal disease |
-pregnancy | No significant association between SO2 and ASD |
Jung et al., 2013 [39] |
Case-Control | 49,073 children from Taiwan | ASD diagnosis according to International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). | Inverse distance weighting method was used to form exposure parameter for PM10 | Cox proportional hazards (PH) model | -age -anxiety -gender -intellectual disabilities -preterm -SES |
-postnatal | The researchers highlighted a 17% increased risk for ASD per each increase of 1 ppb in SO2 levels (95%CI 1.09–1.27) |