How Does Child Sex Play a Role in Early Detection of ASD? Evidence for Sex Disparities in Timely Screening Access

Background: Females appear to experience delayed diagnosis of autism spectrum disorders relative to males. Existing research indicates that age of first parental concern does not differ by sex (Ramsey et al., 2018); however, a greater delay was observed for females in receiving an ASD diagnosis (Begeer et al., 2013). The ABCD Early Screening Project, a multi-stage screening protocol embedded within Early Intervention (EI) agencies, provides a platform to study how sex disparities may emerge during the early ASD detection process.

Objectives: We examined how child sex predicts movement through a three-stage, ASD screening and assessment protocol, considering sex differences in retention versus drop-out between stages, time between stages, and child age at each stage. Secondly, we assessed whether symptomatology and demographic factors predicted sex differences in rates of retention or in time elapsed between stages.

Methods: Participants were 1,590 males and 859 females screened through the ABCD Project; eligible children were aged 14-36 months and enrolled in EI programs. At Stage 1, parents completed the Brief Infant-Toddler Social Emotional Assessment (BITSEA) and Parents’ Observation of Social Interaction (POSI); those screening at-risk for ASD (scores above cut-points) were referred to Stage 2, a brief play-based observational screener (the Screening Tool for Autism in Toddlers; STAT). Those with at-risk STAT scores were referred for a comprehensive diagnostic assessment (Stage 3).

Results: Among those screening positive for ASD risk at Stage 1, males (65.2%) were more likely than females (56.6%) to proceed to Stage 2, X²(1,566)=5.22, p<0.05, indicating an initial disparity in screening follow-through; see Figure 1. Within these screen-positive children at Stage 1, females had higher parent-reported ASD-related competencies, t(356.79)=-2.36, p<.05 but similar parent-reported ASD-related problems t(353.29)=1.36, ns, on the BITSEA. Demographic factors (child race, language, SES) did not contribute to the differential drop-out. At Stage 2, among those screening positive on the STAT, males (83.5%) and females (76.5%) were similarly likely to proceed to Stage 3, X² (1,N=391)=2.66, ns, suggesting that the initial follow-through disparity is not further exacerbated at Stage 3. In terms of ASD symptomatology among screen-positive children at each stage, Stage 2 STAT scores [t(138.337)=1.89, ns] and Stage 3 ADOS scores [t(77.663) = 1.11, ns] did not differ by sex. In terms of age at screening, males and females did not differ, resulting in mean diagnostic ages of 28.1 months for both males and females; see Figure 2.

Conclusions: Among children screening positive for ASD risk, females were less likely than males to proceed with subsequent screening and assessment. Within those screening positive, females also had higher ASD-related competencies than males, perhaps reducing urgency among parents and EI providers to pursue further screening. Of interest, there were no sex differences in observed ASD behaviors among boys and girls on the STAT or ADOS-2.