To calculate odds ratios (ORs) for ASD associated with exposure to specific pollutants, we fit separate logistic regression models with ASD case status as the dependent variable and quintiles of each pollutant as the independent variable, both adjusted for child's sex and stratified by sex.
For example, a selection bias may arise when factors distinguish the ASD case group from the underlying population above and beyond having symptoms of ASD, such as race, socioeconomic position, or access to health services.
Regions of the corresponding slide in the matched ASD case where t fell below the lower fence were identified as possible dysplasias.
Clinicians determine whether the ASD case definition is met by reviewing a compiled record of all relevant abstracted data.
Since the initial recruitment, 416 new children including one ASD case have participated in the study and are included in the data used in this report.
However in a separate study, it was found that even if African-American children, particularly with comorbid ID, met the ASD case definition, it was not necessarily recorded in their case notes [5].
