Distribution of Autistic Traits in a Taiwanese Population of Children Aged 6-8 Years

Background: It is well accepted that Autism Spectrum Disorders (ASDs) represent one end of a larger spectrum of quantitative impairment that is continuously distributed in the general population. The Social Responsiveness Scale (SRS) is an instrument that characterizes quantitative impairments in social awareness, cognition, communication, motivation, and repetitive behavior/restricted interests that define ASD, and provides a more subtle characterization of individual symptoms than using traditional classification systems. This tool is particularly feasible for assessing autistic traits in large, population-based studies because it can quantify the spectrum of dimensional impairments of ASD.  Implementing the SRS in a large population will allow it to be standardized across different settings and against different norms and subgroups such as gender, age, or racial/ethnical background.

Objectives: To examine the distribution of dimensional autistic traits in a large Taiwanese population of children aged 6-8 years.

Methods: Caregiver-reported SRS data were collected by an epidemiologic autism study recently conducted in PingTung Taiwan.  Raw scores of the total SRS and five subscales (social awareness, social cognition, social communication, social motivation, and autistic mannerisms) were compared between male and female children.  As recommended in the literature, a raw score of >=70 in males and >=65 in females is a cut-point that provides evidence for the presence of an ASD.  Based on these cut-points, we defined clinical vs. non-clinical groups separately for males and females.  Comparison of social demographic characteristics between groups was examined by calculating Odds Ratios (OR) and 95% Confidence Intervals (CI).

Results: This study includes participants who completed the SRS and whose child’s sex is known.  As a result, 1384 males and 1507 females are included in the analysis.  Of those, 172 males and 185 females met the recommended clinical cut-off.  SRS total scores, social awareness, social communication and autistic mannerisms are significantly higher in males than females with p-values all <0.0001.  While social cognition is higher in males than females (p<0.05), no significant difference in social motivation.  The male clinical group (SRS>=70), as compared to the male non-clinical group, is 3.11 times (95%CI: 1.87-5.18) more likely to have father’s education <=middle school, and 4.52 times (95%CI: 2.62-7.79) more likely to have mother’s education <=middle school.  Similar association patterns are observed in females where the odds of having father’s education <=middle school is more than 5 times (OR=5.29, 95%CI: 3.14-8.92) higher, and having mother’s education <=middle school 4 times (OR= 4.43, 95%CI: 2.64-7.45) higher, in the female clinical group (SRS>=65) than the female non-clinical group.  Additionally, males in the clinical group are almost 3 times (OR=2.82, 95%CI: 1.71-4.66) more likely than males in the non-clinical group to be born preterm.

Conclusions:  Parental education level is highly associated with SRS clinical status, as children who met the SRS clinical cut-point are more likely to have their parents’ education <=middle school.  It is not clear how parental education is associated with SRS measured behaviors.  Further investigation on how psychometrics of the Chinese mandarin SRS, and potential cultural expectations, may have affected reporting on child behaviors will be discussed.