Autism in Glasgow: cumulative incidence and the effects of referral age, deprivation and geographical location

Mapping the genetic and environmental aetiology of autistic traits in Sweden and the United Kingdom

Background

Autistic traits are influenced by both genetic and environmental factors, and are known to vary geographically in prevalence. But to what extent does their aetiology also vary from place to place?

Methods

We applied a novel spatial approach to data on autistic traits from two large twin studies, the Child and Adolescent Twin Study in Sweden (CATSS; N = 16,677, including 8307 twin pairs) and the Twins Early Development Study in the UK (TEDS; N = 11,594, including 5796 twin pairs), to explore how the influence of nature and nurture on autistic traits varies from place to place.

Results

We present maps of gene‐ and environment‐ by geography interactions in Sweden and the United Kingdom (UK), showing geographical variation in both genetic and environmental influences across the two countries. In Sweden genetic influences appear higher in the far south and in a band running across the centre of the country. Environmental influences appear greatest in the south and north, with reduced environmental influence across the central band. In the UK genetic influences appear greater in the south, particularly in more central southern areas and the southeast, the Midlands and the north of England. Environmental influences appear greatest in the south and east of the UK, with less influence in the north and the west.

Conclusions

We hope this systematic approach to identifying aetiological interactions will inspire research to examine a wider range of previously unknown environmental influences on the aetiology of autistic traits. By doing so, we will gain greater understanding of how these environments draw out or mask genetic predisposition and interact with other environmental influences in the development of autistic traits.

Family Experiences with the Diagnosis of Autism Spectrum Disorder: System Barriers and Facilitators of Efficient Diagnosis

This paper examines family experiences with the efficiency of ASD diagnosis. Children were age 8 or younger with ASD (n = 450). Outcomes were delay from first parent concern to diagnosis, shifting diagnoses, and being told child did not have ASD. Predictors were screening, travel distance, and problems finding providers. Logit models were used to examine associations. Screening was associated with reduced delay in diagnosis; problems finding providers were associated with greater delay. Screening, travel distance, and delay in diagnosis were associated with shifting diagnoses and being told child did not have ASD. Physician and parent training in communication and addressing mental health professional shortages and maldistribution may improve the diagnosis experiences of families of children with ASD.

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

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.