1. Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden
2. Centre for Epidemiology and Community Medicine, Stockholm County Council, Stockholm, Sweden
3. Department of Epidemiology and Biostatistics, Drexel University Dornsife School of Public Health, Philadelphia, Pennsylvania
4. A. J. Drexel Autism Institute, Philadelphia, Pennsylvania
5. Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden