Differences in the Behavioral Phenotype of Autism Spectrum Disorder in a Population Sample of Somali, White, Non-Somali Black, and Hispanic Children in Minneapolis

Background: Previous research suggests that immigrant families from countries with a low human resource index are at increased risk for autism spectrum disorder (ASD) and have greater levels of impairment than other children with ASD (e.g., Barnevik-Olsson et al. 2008; Keen et al. 2010; Magnusson et al. 2012).

Objectives: Results are presented from a public health surveillance project in Minneapolis designed to determine if more Somali children had ASD than non-Somali children. A secondary goal was to identify differences in the behavioral phenotype of ASD across racial and ethnic groups; this is the focus of the present study.

Methods:  A multi-step records review process was used to identify cases of ASD from educational and medical records of Minneapolis children who were 7-9 years old in 2010. Data documenting DSM-IV-TR autism symptoms, intellectual ability, and related behavioral and medical concerns were collected and used to characterize behavioral phenotype. Frequencies and percentages were used to describe DSM-IV-TR symptoms and associated features and were compared across Somali, white, non-Somali black, and Hispanic children with ASD. Categorical differences in ASD symptoms, cognitive level, and associated features across racial/ethnic groups were assessed with chi-square analyses for nominal data, and odds ratios with confidence intervals of 95% were used to estimate effect size. Differences in number of symptoms and features documented across racial/ethnic groups were compared using ANOVA as a metric of symptom severity.

Results: Somali children with ASD were far more likely to have intellectual disability (ID) than children with ASD in all other racial and ethnic groups. 100% of Somali children with cognitive data in their records had IQ ≤ 70 compared with 32.6% for the total sample. Regarding DSM-IV-based symptoms, Somali children were more likely than all other racial/ethnic groups to have lack of pretend play documented in their records and more likely than white and Hispanic children to have deficits in seeking to share enjoyment. Regarding restricted/repetitive behaviors, Somali children were more likely than Hispanic children to have preoccupations with parts of objects. Fixated interests were noted more frequently for white children than Hispanic children. White and Somali children were documented more often than Hispanic children with repetitive motor mannerisms. Somali and white children had a greater number of DSM-IV repetitive behavior symptoms documented in their records than Hispanic children, and Somali children were more likely to have co-occurring concerns of abnormalities in eating and drinking patterns than white and non-Somali Black children. In all cases, differences were no longer significant when the sample was limited to those with ASD+ID.

Conclusions: Results indicate a striking difference in the presence of ID in Somali children with ASD compared with other children. These results are consistent with previous research that found immigrants from low human resource index countries, and Somali children in particular, had higher rates of ASD+ID than other groups. Potential reasons for these findings and implications for practitioners will be discussed.