Possible Association between Parental Socioeconomic Status and Development of Autistic Traits among Children Screened 36 Months after Birth in the Norwegian Mother and Child Cohort Study

............................................................................................. .........3 Introduction..................................................................................................3 Previous studies on the possible link between socioeconomic status and autism....... 4 Aims of the study.......................................................................................... 5 Materials and Methods................................................................................... 5 MoBa and the ABC study............................................................................... 5 The screening algorithm and the Social Communication Questionnaire – SCQ......... 6 Diagnostic evaluation....................................................................................7 Exposure and outcome variables..................................................................... 8 Statistical analyses....................................................................................... 9 Possible selection bias in our study..................................................................10 Results........................................................................................................ 10 SCQ-33 >=12 as outcome variable.................................................................. 12 ASD-ST as outcome variable.......................................................................... 18 ASD as outcome variable...............................................................................20 Investigation of possible selection bias..............................................................21 Discussion....................................................................................................25 Main results.................................................................................................25 Strengths and weaknesses.............................................................................26 Conclusion..................................................................................................27 References....................................................................................................28