摘要：Objectives. We estimated the effect of community and school district resources on the identification of children with autistic disorder. Methods. Latent growth curve regression models were applied to school district–level data from one large state. Results. The rate of identification of autistic disorder increased on average by 1.0 child per 10000 per year ( P <.001), with statistically significant district variation. After adjustment for district and community characteristics, each increase in decile of school revenue was associated with an increase of 0.16 per 10000 children identified with autistic disorder. The proportion of economically disadvantaged children per district was inversely associated with autistic disorder cases. Conclusions. District revenue was associated with higher proportions of children identified with autistic disorder at baseline and increasing rates of identification when measured longitudinally. Economically disadvantaged communities may need assistance to identify children with autistic spectrum disorders and other developmental delays that require attention. Autistic spectrum disorders (ASDs) are a disabling continuum of disorders affecting 2 to 4 of every 1000 live births. 1, 2 The core set of defining features includes deficits in verbal and nonverbal communication and restricted and repetitive patterns of behavior. 3, 4 The prevalence of ASD appears to be greater than previously thought, at least in part owing to improved ascertainment. 5 The etiology of ASDs is uncertain. As yet, the disorders can be defined only by a set of specific behaviors. 6 Twin studies have provided evidence of a strong genetic component, and multiple genetic loci have been identified, but no association with specific phenotypes has been established. 7 Specific environmental factors, such as maternal rubella, also have been associated with ASDs. 8 Other potential causes of ASDs, such as diet, 9– 11 gastrointestinal pathology, 12 chemical imbalance, 13 and vaccines, 14– 19 have been posited but remain controversial. Evidence for a dysfunction of the neuroimmune complex is mounting, but it requires more investigation into specific mechanisms. 20– 24 The association between ASDs and parenting practices 25 has been completely discredited, and the association with socioeconomic status 26– 30 is largely viewed as spurious. Successful behavioral interventions have been developed that improve language and socialization skills and decrease stereotyped and self-injurious behavior among children with ASDs. 31 In part to ensure that they receive these services, but primarily to ensure that they receive the “free, appropriate education” to which they are entitled, children with ASDs are eligible for special education services through the Individuals With Disabilities Education Act. 32 ASDs were identified as a separate disabling condition qualifying children for special education in 1990. 33 Special education services, available for children from birth to age 21, can include participation in specialized classrooms, one-on-one instruction, and intensive behavioral interventions. 3, 34– 36 Despite the fact that ASDs can be identified in children as young as 18 months, 37 a large majority of these children are not identified until they are of school age. 38– 40 Unless parents exhibit distress or proactively discuss their concerns with pediatricians, physicians are often slow to recognize disorders in children or miss them altogether, even when signs and symptoms are apparent. 41– 44 Even when parents do express concern, recognition and referral are often delayed. For example, Howlin and Moore found that although the average age of diagnosis was 6 years, parents generally expressed concern about related problems much earlier. 39 Glascoe found that the identification of developmental disorders is usually delayed to the point that the school system—as opposed to the health system—identifies 70% of children with developmental delays. 38 Palfrey and colleagues found that when identification of more polymorphous phenotypes such as ASDs was delayed, the proportion identified by the school system was closer to 80%. 43 In their large-scale prevalence study of ASDs, Yeargin-Allsopp and colleagues found that more than 75% of children with ASDs were identified through the school system. 2 Clearly, schools play an important role in identifying children with developmental disorders such as ASDs; however, their methods of identification are suboptimal. For example, Yeargin-Allsopp found that in one metropolitan area, 18% of children who qualified for a diagnosis of ASDs according to study criteria were receiving special education services but had not been recognized as having ASDs by the school. 2 There is little research, however, on the characteristics of schools and school systems that are associated with timely recognition and provision of services for children with ASDs. In their study of all 50 states, Lester and Kelman found that state policies were highly predictive of rates of identified learning disabilities, whereas state sociodemographic characteristics were not. 45 They acknowledged, however, that it is difficult to summarize the sociodemographic characteristics of an entire state, a factor that may have influenced their results. They also pointed to the need for more fine-grained analysis. One possibility is that school districts with greater resources are more effective at identifying and providing services to children with ASDs. Services for children with ASDs are often costly and can represent a considerable drain on related resources. 46, 47 The US Department of Education reports that there are considerable inequities in both revenues and special education spending by district across the United States. 48 To our knowledge, there is no research that examines how these district characteristics influence the recognition of and provision of services to children with special needs. The current study used data from one large state to examine differences in the proportion of children identified with autistic disorder and the rate at which they were identified, as a function of school district resources. We focused on autistic disorder rather than the spectrum of disorders because autistic disorder represents the most severe and phenotypically distinct end of the spectrum, 49 and is therefore the most reliably and validly diagnosed. 50, 51
