Table 1.
Description of the participating birth cohort studies.
| Cohort study | Setting | Air pollution | Autistic traits | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Location | Pregnancy period | Pollutants | % of birth addresses in urban areas | Test | Age (years) | Evaluator | na | n (%) within borderline or clinical range | n (%) within clinical range only | |
| CATSS | Stockolm (Sweden) | 1992–2000 | NO2, NOx, PM, traffic intensity, traffic load | 45.7 | ASD module (A-TAC) | 10 | Parents | 2,437 | 78 (3.2) | 27 (1.1) |
| Generation R | Rotterdam (the Netherlands) | 2001–2005 | NO2, NOx, PM, traffic intensity, traffic load | 100.0 | PDP subscale (CBCL½–5) | 6 | Parents | 3,955 | 336 (8.5) | 143 (3.6) |
| Adapted 18‑item version of SRS | 6 | Parents | 3,231 | NAb | NAb | |||||
| GASPII | Rome (Italy) | 2003–2004 | NO2, NOx, PM, traffic intensity, traffic load | 100.0 | PDP subscale (CBCL½–5) | 4 | Parents | 514 | 63 (12.3) | 15 (2.9) |
| INMA | Gipuzkoa (Spain) | 2006–2008 | NO2, NOx | 89.1 | CAST | 4 | Psychologist | 357 | 17 (4.8) | 3 (0.8) |
| Sabadell (Spain) | 2004–2006 | NO2, NOx, PM, traffic load | 100.0 | CAST | 4 | Psychologist | 295 | 10 (3.4) | 2 (0.7) | |
| Valencia (Spain) | 2004–2005 | NO2, NOx, traffic load | 92.7 | CAST | 5 | Psychologist | 521 | 37 (7.1) | 10 (1.9) | |
| Abbreviations: ASD, autism spectrum disorder; A-TAC, Autism–Tics, Attention Deficit and Hyperactivity Disorders, and Other Comorbidities Inventory; CBCL, Child Behavior Checklist; CAST, Childhood Autism Spectrum Test; NO2, nitrogen dioxide; NOx, nitrogen oxides; PDP, pervasive developmental problems; PM, PM ≤ 10 μm (PM10), PM ≤ 2.5 μm (PM2.5), PM between 2.5 and 10 μm (PMcoarse), PM2.5absorbance (reflectance of PM2.5 filters); SRS, Social Responsiveness Scale; Traffic intensity, traffic intensity on the nearest road; Traffic load, total traffic load (intensity × length) on all major roads within 100-m buffer. aNumber of children with air pollution, autistic traits, and potential confounders variables available. bNA, not applicable because the cut-off points for autistic traits within the borderline/clinical range and within the clinical range have not been defined for the 18-item version of the SRS; score evaluated only as a continuous quantitative outcome. | ||||||||||