Brief Report
Demographic profile of families and children in the Study to Explore Early Development (SEED): Case-control study of autism spectrum disorder

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Abstract

Background

The Study to Explore Early Development (SEED) is designed to enhance knowledge of autism spectrum disorder characteristics and etiologies.

Objective

This paper describes the demographic profile of enrolled families and examines sociodemographic differences between children with autism spectrum disorder and children with other developmental problems or who are typically developing.

Methods

This multi-site case-control study used health, education, and birth certificate records to identify and enroll children aged 2–5 years into one of three groups: 1) cases (children with autism spectrum disorder), 2) developmental delay or disorder controls, or 3) general population controls. Study group classification was based on sampling source, prior diagnoses, and study screening tests and developmental evaluations. The child's primary caregiver provided demographic characteristics through a telephone (or occasionally face-to-face) interview. Groups were compared using ANOVA, chi-squared test, or multinomial logistic regression as appropriate.

Results

Of 2768 study children, sizeable proportions were born to mothers of non-White race (31.7%), Hispanic ethnicity (11.4%), and foreign birth (17.6%); 33.0% of households had incomes below the US median. The autism spectrum disorder and population control groups differed significantly on nearly all sociodemographic parameters. In contrast, the autism spectrum disorder and developmental delay or disorder groups had generally similar sociodemographic characteristics.

Conclusions

SEED enrolled a sociodemographically diverse sample, which will allow further, in-depth exploration of sociodemographic differences between study groups and provide novel opportunities to explore sociodemographic influences on etiologic risk factor associations with autism spectrum disorder and phenotypic subtypes.

Section snippets

Methods

SEED is a multi-site, case-control study, the methods for which have been described previously.19 Cases (ASD group) comprise children with ASD verified by clinical evaluation. The two comparison groups include a general Population group and a Developmental Delays/Disorders group. Eligible children were born between September 1, 2003 and August 31, 2006 in a study catchment area, resided there at first study contact, and lived with a family member or other caregiver aged ≥18 years, who had

Results

Of 3769 children enrolled between December 2007 and September 2011, the caregivers of 3048 (80.9%) children were interviewed. There were 2768 children whose caregivers were interviewed and who received a final classification, including 697 (25.2%) in the ASD group, 1084 (39.2%) in the Developmental Delays/Disorders group (305 [11.0%] with and 779 [28.1%] without ASD characteristics), and 987 (35.7%) in the Population group. Most caregiver respondents (99.0%) were biological mothers; .6% were

Discussion

Through the use of a broad diagnostic net, involving both clinical and educational recruitment sources, SEED successfully enrolled a highly diverse sample of participants, including minorities and low socioeconomic status families, with distributions comparable to the racial and ethnic diversity in the United States.30 While a number of large, population-based studies of ASD using surveillance or administrative data have been conducted in North America, (e.g. Refs. 1, 31, 32, 33) SEED improves

Conclusion

The primary goal of SEED is to test important hypotheses related to ASD phenotype and etiology, through collection of in-depth data that will enable the testing of multiple different, but potentially interrelated, hypotheses. The current report demonstrates that SEED methods yielded a well-defined and socioeconomically diverse study sample that will provide novel opportunities to explore the influence of socioeconomic characteristics on etiologic risk factor associations with ASD and ASD

Acknowledgments

Patrick Thompson made important contributions to data selection, management and cleaning for this paper. The investigators gratefully acknowledge the project staff and the enrolled families. A preliminary version of these results was presented at the International Meeting for Autism Research, Toronto, Canada, on May 18, 2012.

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  • Cited by (0)

    Conflict of interest statement: None of the authors report any conflicts of interest.

    Disclosures: This project was supported by Centers for Disease Control and Prevention (CDC) Cooperative Agreements announced under the following RFAs: 01086, 02199, DD11-002, DD06-003, DD04-001, and DD09-002. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

    1

    Current address: Centers for American Indian and Alaska Native Health, Campus Box F800, Nighthorse Campbell Native Health Building, 13055 E 17th Avenue, Aurora, CO 80045, USA.

    2

    Current address: Centers for Disease Control and Prevention, 1600 Clifton Road NE, Mailstop E-86, Atlanta, GA 30329-4027, USA.

    3

    Current address: Department of Epidemiology, CB #7435, University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC 27599-7435, USA.

    4

    Current address: ASPIRE Program, El Camino Hospital, Behavioral Health Services, 2500 Grant Rd, Mountain View, CA 94040-4378, USA.

    5

    Current address: Department of Public Health, Institute of Epidemiology and Social Medicine, Aarhus University, Bartholins Allé 2, Bldg 1260, DK-8000 Aarhus C, Denmark.

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