Matthew J. Maenner

Timing of Identification Among Children With an Autism Spectrum Disorder: Findings From a Population-Based Surveillance Study

OBJECTIVE At what age are children with an autism spectrum disorder (ASD) identified by community providers? What factors influence the timing of when children are identified with ASDs? This study examined the timing of when children with ASDs are identified. METHOD Data came from 13 sites participating in the Centers for Disease Control and Preventions 2002 multisite ongoing autism surveillance program, the Autism and Developmental Disabilities Monitoring Network. Survival analysis was used to examine factors that influence the timing of community-based identification and diagnosis. RESULT Data from health and education records reveal that the median age of identification was 5.7 years (SE 0.08 years). Parametric survival models revealed that several factors were associated with a younger age of identification: being male, having an IQ of 70 or lower, and having experienced developmental regression. Significant differences in the age of identification among the 13 sites were also discovered. CONCLUSIONS The large gap between the age at which children can be identified and when they actually are identified suggests a critical need for further research, innovation, and improvement in this area of clinical practice.

Advanced Parental Age and the Risk of Autism Spectrum Disorder

This study evaluated independent effects of maternal and paternal age on risk of autism spectrum disorder. A case-cohort design was implemented using data from 10 US study sites participating in the Centers for Disease Control and Preventions Autism and Developmental Disabilities Monitoring Network. The 1994 birth cohort included 253,347 study-site births with complete parental age information. Cases included 1,251 children aged 8 years with complete parental age information from the same birth cohort and identified as having an autism spectrum disorder based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria. After adjustment for the other parents age, birth order, maternal education, and other covariates, both maternal and paternal age were independently associated with autism (adjusted odds ratio for maternal age ≥35 vs. 25–29 years = 1.3, 95% confidence interval: 1.1, 1.6; adjusted odds ratio for paternal age ≥40 years vs. 25–29 years = 1.4, 95% confidence interval: 1.1, 1.8). Firstborn offspring of 2 older parents were 3 times more likely to develop autism than were third- or later-born offspring of mothers aged 20–34 years and fathers aged <40 years (odds ratio = 3.1, 95% confidence interval: 2.0, 4.7). The increase in autism risk with both maternal and paternal age has potential implications for public health planning and investigations of autism etiology.

Socioeconomic inequality in the prevalence of autism spectrum disorder: evidence from a U.S. cross-sectional study.

Background This study was designed to evaluate the hypothesis that the prevalence of autism spectrum disorder (ASD) among children in the United States is positively associated with socioeconomic status (SES). Methods A cross-sectional study was implemented with data from the Autism and Developmental Disabilities Monitoring Network, a multiple source surveillance system that incorporates data from educational and health care sources to determine the number of 8-year-old children with ASD among defined populations. For the years 2002 and 2004, there were 3,680 children with ASD among a population of 557 689 8-year-old children. Area-level census SES indicators were used to compute ASD prevalence by SES tertiles of the population. Results Prevalence increased with increasing SES in a dose-response manner, with prevalence ratios relative to medium SES of 0.70 (95% confidence interval [CI] 0.64, 0.76) for low SES, and of 1.25 (95% CI 1.16, 1.35) for high SES, (P<0.001). Significant SES gradients were observed for children with and without a pre-existing ASD diagnosis, and in analyses stratified by gender, race/ethnicity, and surveillance data source. The SES gradient was significantly stronger in children with a pre-existing diagnosis than in those meeting criteria for ASD but with no previous record of an ASD diagnosis (p<0.001), and was not present in children with co-occurring ASD and intellectual disability. Conclusions The stronger SES gradient in ASD prevalence in children with versus without a pre-existing ASD diagnosis points to potential ascertainment or diagnostic bias and to the possibility of SES disparity in access to services for children with autism. Further research is needed to confirm and understand the sources of this disparity so that policy implications can be drawn. Consideration should also be given to the possibility that there may be causal mechanisms or confounding factors associated with both high SES and vulnerability to ASD.

Prevalence and functioning of children with cerebral palsy in four areas of the United States in 2006: a report from the Autism and Developmental Disabilities Monitoring Network.

AIM To estimate the prevalence of cerebral palsy (CP) and the frequency of co-occurring developmental disabilities (DDs), gross motor function (GMF), and walking ability using the largest surveillance DD database in the US. METHODS We conducted population-based surveillance of 8-year-old children in 2006 (N=142,338), in areas of Alabama, Georgia, Wisconsin, and Missouri. This multi-site collaboration involved retrospective record review at multiple sources. We reported CP subtype, co-occurring DDs, Gross Motor Function Classification System (GMFCS) level, and walking ability as well as CP period prevalence by race/ethnicity and sex. RESULTS CP prevalence was 3.3 (95% confidence interval [CI]: 3.1-3.7) per 1000 and varied by site, ranging from 2.9 (Wisconsin) to 3.8 (Georgia) per 1000, 8-year olds (p<0.02). Approximately 81% had spastic CP. Among children with CP, 8% had an autism spectrum disorder and 35% had epilepsy. Using the GMFCS, 38.1% functioned at the highest level (I), with 17.1% at the lowest level (V). Fifty-six percent were able to walk independently and 33% had limited or no walking ability. INTERPRETATION Surveillance data are enhanced when factors such as functioning and co-occurring conditions known to affect clinical service needs, quality of life, and health care are also considered.

Services for adults with an autism spectrum disorder.

The need for useful evidence about services is increasing as larger numbers of children identified with an autism spectrum disorder (ASD) age toward adulthood. The objective of this review was to characterize the topical and methodological aspects of research on services for supporting success in work, education, and social participation among adults with an ASD and to propose recommendations for moving this area of research forward. We reviewed the literature published in English from 2000 to 2010 and found that the evidence base about services for adults with an ASD is underdeveloped and can be considered a field of inquiry that is relatively unformed. Extant research does not reflect the demographic or impairment heterogeneity of the population, the range of services that adults with autism require to function with purposeful lives in the community, and the need for coordination across service systems and sectors. Future studies must examine issues related to cost and efficiency, given the broader sociopolitical and economic context of service provision. Further, future research needs to consider how demographic and impairment heterogeneity have implications for building an evidence base that will have greater external validity.

Prevalence of cerebral palsy, co‐occurring autism spectrum disorders, and motor functioning – Autism and Developmental Disabilities Monitoring Network, USA, 2008

The aim of this study was to report the prevalence and characteristics of children with cerebral palsy (CP).

Prevalence of CGG Expansions of the FMR1 Gene in a US Population-Based Sample

The primary goal of this study was to calculate the prevalence of the premutation of the FMR1 gene and of the “gray zone” using a population‐based sample of older adults in Wisconsin (n = 6,747 samples screened). Compared with past research, prevalence was relatively high (1 in 151 females and 1 in 468 males for the premutation and 1 in 35 females and 1 in 42 males for the gray zone as defined by 45–54 CGG repeats). A secondary study goal was to describe characteristics of individuals found to have the premutation (n = 30, 7 males and 23 females). We found that premutation carriers had a significantly higher rate of divorce than controls, as well as higher rates of symptoms that might be indicative of fragile X‐associated tremor ataxia syndrome (FXTAS; numbness, dizziness/faintness) and fragile X primary ovarian insufficiency (FXPOI; age at last menstrual period). Although not statistically significant, premutation carriers were twice as likely to have a child with disability.

Developmental Trajectories in Adolescents and Adults With Autism: The Case of Daily Living Skills

OBJECTIVE This study aimed to investigate the longitudinal course of daily living skills in a large, community-based sample of adolescents and adults with autism spectrum disorders (ASD) over a 10-year period. METHOD Adolescents and adults with ASD (n = 397) were drawn from an ongoing, longitudinal study of individuals with ASD and their families. A comparison group of 167 individuals with Down syndrome (DS) were drawn from a linked longitudinal study. The Waisman Activities of Daily Living Scale was administered four times over a 10-year period. RESULTS We used latent growth curve modeling to examine change in daily living skills. Daily living skills improved for the individuals with ASD during adolescence and their early 20s, but plateaued during their late 20s. Having an intellectual disability was associated with lower initial levels of daily living skills and a slower change over time. Individuals with DS likewise gained daily living skills over time, but there was no significant curvature in the change. CONCLUSIONS Future research should explore what environmental factors and interventions may be associated with continued gains in daily living skills for adults with ASD.

Potential Impact of DSM-5 Criteria on Autism Spectrum Disorder Prevalence Estimates

IMPORTANCE The DSM-5 contains revised diagnostic criteria for autism spectrum disorder (ASD) from the DSM-IV-TR. Potential impacts of the new criteria on ASD prevalence are unclear. OBJECTIVE To assess potential effects of the DSM-5 ASD criteria on ASD prevalence estimation by retrospectively applying the new criteria to population-based surveillance data collected for previous ASD prevalence estimation. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional, population-based ASD surveillance based on clinician review of coded behaviors documented in childrens medical and educational evaluations from 14 geographically defined areas in the United States participating in the Autism and Developmental Disabilities Monitoring (ADDM) Network in 2006 and 2008. This study included 8-year-old children living in ADDM Network study areas in 2006 or 2008, including 644 883 children under surveillance, of whom 6577 met surveillance ASD case status based on the DSM-IV-TR. MAIN OUTCOMES AND MEASURES Proportion of children meeting ADDM Network ASD criteria based on the DSM-IV-TR who also met DSM-5 criteria; overall prevalence of ASD using DSM-5 criteria. RESULTS Among the 6577 children classified by the ADDM Network as having ASD based on the DSM-IV-TR, 5339 (81.2%) met DSM-5 ASD criteria. This percentage was similar for boys and girls but higher for those with than without intellectual disability (86.6% and 72.5%, respectively; P < .001). A total of 304 children met DSM-5 ASD criteria but not current ADDM Network ASD case status. Based on these findings, ASD prevalence per 1000 for 2008 would have been 10.0 (95% CI, 9.6-10.3) using DSM-5 criteria compared with the reported prevalence based on DSM-IV-TR criteria of 11.3 (95% CI, 11.0-11.7). CONCLUSIONS AND RELEVANCE Autism spectrum disorder prevalence estimates will likely be lower under DSM-5 than under DSM-IV-TR diagnostic criteria, although this effect could be tempered by future adaptation of diagnostic practices and documentation of behaviors to fit the new criteria.

Child disability screening, nutrition, and early learning in 18 countries with low and middle incomes: data from the third round of UNICEF's Multiple Indicator Cluster Survey (2005-06).

BACKGROUND Child disability is an emerging global health priority. To address the need for internationally comparable information about the frequency and situation of children with disabilities, UNICEF has recommended that countries include the Ten Questions screen for disability in the Multiple Indicator Cluster Survey (MICS) programme. We examined child disability screening and its association with nutrition and early learning in countries with low and middle incomes. METHODS Cross-sectional data for the percentage of children screening positive for or at risk of disability were obtained for 191 199 children aged 2-9 years in 18 countries participating in the third round of MICS in 2005-06. Screening results were descriptively analysed according to sociodemographic, nutritional, early-learning, and schooling variables. We constructed a weighted analysis to account for the sampling design in every country and tested for differences within countries using chi(2) analyses. FINDINGS A median 23% (range 3-48) of children aged 2-9 years screened positive for disability in the 18 participating countries. For children aged 2-4 years, screening positive for disability was significantly more likely in children who were not breastfed versus those who were (median 36% [9-56] vs 26% [4-51]) in eight of 18 countries, in children who had not received vitamin A supplementation versus those who had (36% [7-53] vs 29% [4-50]) in five of ten countries assessed, in children who met criteria for stunting (26% [6-54]) or being underweight (36% [3-61]) versus those who did not (25% [3-42] and 26% [4-43], respectively) in five of 15 countries assessed for stunting and in seven of 15 countries assessed for being underweight, and in those who participated in few early-learning activities versus others (31% [7-54] vs 24% [4-51]) in eight of 18 countries. Children aged 6-9 years who did not attend school screened positive for disability more often than did children attending school (29% [2-83] vs 22% [3-47]) in eight of 18 countries. INTERPRETATION Our results draw attention to the need for improved global capacity to assess and provide services for children at risk of disability. Further research is needed in countries with low and middle incomes to understand and address the role of nutritional deficiencies and restricted access to learning opportunities as both potential antecedents of childhood disability and consequences of discrimination. FUNDING UNICEF; Department of Population Health Sciences, University of Wisconsin-Madison, USA.