32181
Title: Sex-Based Differences in the Diagnosis and Expression of Autism Spectrum Disorder (ASD) Among Preschool-Age Children: Findings from Population-Based Surveillance in New Jersey
There are few studies of ASD in the preschool period based on detailed information derived from active surveillance of large, population-based, cohorts. While Autism Spectrum Disorder (ASD) prevalence estimates have increased from 6.5 per 1,000 in 2000 to 1.7 per 1,000 in 2014, one finding has remained consistent overtime, the male to female ratio. Males are four times more likely than females to be diagnosed with ASD.
Objectives:
The purpose of this study is to identify sex-based differences in the diagnosis and expression of autism among preschool age children in a large, multi-cohort, population-based sample.
Methods:
Children with ASD born in 2006, 2008 and 2010 and residing in Essex and Union counties New Jersey in 2010, 2012 and 2014, respectively, were identified from successive cycles of active (multiple source) surveillance, using a Centers for Disease Control and Prevention (CDC), ascertainment method, based on retrospective review and analysis of information contained in health and education records. Information on the expression of ASD according to DSM criteria, associated features, level of cognitive functioning, previous ASD diagnosis and ASD tests provided, as well as demographic information was systematically abstracted and analyzed. Group differences were compared using Pearson Chi-Square and Fisher’s Exact Tests.
Results:
A total of 1,270 four-year-old children with ASD were confirmed across three cycles of surveillance. Boys with ASD outnumbered girls with ASD 4 to 1 (boys = 1,012, 80%; girls = 258, 20%). Boys and girls with ASD had similar proportions of cognitive impairment (boys = 39%; girls = 34%). Overall, 57% had a previous ASD diagnosis from a community-based provider and the proportion of ASD-diagnosed children did not differ by sex. Boys were more likely to be administered an Autism test than girls (37% vs 31%, p<0.05). Boys and girls with ASD manifested differently. With regard to DSM criteria, boys were more likely to exhibit deficits in nonverbal communication, such as eye contact, than girls (90% vs 85%, p<0.01). In addition, boys were also more likely to exhibit restricted patterns of interest (48% vs 34%, p<0.001) and inflexible adherence to nonfunctional routines (78% vs 70%, p<0.1). Boys demonstrated sensory processing deficits more frequently (47% vs 37%, p<.01) than girls and boys were more likely to exhibit the associated features: aggression, opposition and hyperactivity than girls (p<0.05).
Conclusions:
The expression of ASD in preschool age boys with ASD is more likely to include deficits in non-verbal communication, as well as to show restricted patterns of interest and non-functional routines than girls with ASD. In addition, young boys with ASD are more likely to express a number of additional, salient, associated features such as hyperactive, oppositional and/or aggressive behavior. Satisfying DSM-5 ASD criteria requires key social communication deficits including deficits in nonverbal communication, presence of restricted and/or repetitive behaviors and/or sensory processing deficits that are manifest in young boys more frequently than girls with ASD, thereby raising the possibility that preschool age girls with ASD will be diagnosed later than boys in the DSM-5 era.