Investigating the Correlation Between Parental Age at Birth and a Diagnosis of Autism Spectrum Disorder in a Sample of Children with Developmental Delays

Background: Past findings have shown that older ages of both the mother and father are correlated with a child receiving a diagnosis of an autism spectrum disorder (ASD) (Lampi, et al. 2013). Previous research focuses primarily on comparison of ASD children to a typically developing population (Gardener, Spiegelman, & Buka, 2009).

Objectives: The main objective of this study was to examine the relation between parental ages for children with an ASD and for children who have other developmental disorders. 

Methods: 213 children evaluated for ASD through the UAB Civitan-Sparks Clinics were included in these retrospective analyses. Demographic information was obtained from intake and referral documents and ADOS severity scores, IQ and language scores were gathered as measures of disorder severity. The dataset was split into a Non-ASD final diagnosis group (n= 95) and an ASD-final-diagnosis group (n= 118). The control group of children in the Non-ASD group was unique from those seen in many similar studies in that they received other developmental diagnoses. 

Results: Groups were not different on variables of gender, ethnicity, age in months (Non-ASD group: M= 62.67, SD= 28.26; ASD group M= 56.01, SD= 27.20), maternal age in years (Non-ASD group M=30.13, SD= 6.35; ASD group M= 32.018, SD= 5.99), paternal age in years (Non-ASD group M= 33.22, SD= 7.47; ASD group M= 33.48, SD= 5.86), overall IQ score, and non-verbal IQ score (all p’s = ns). Children with ASD obtained poorer language scores across measures. ADOS severity scores were also found to be significantly different between the two groups, t(211)= -9.39, p < 0.01, as would be expected.

            In the Non-ASD group, a positive correlation was found between receptive language score and maternal age, r(56)= 0.264, p < 0.05, no such correlation was found in the ASD group (p = ns), or for paternal age in either group (p = ns). A positive correlation was also found between maternal age and overall IQ in the ASD group: r(39)= 0.473, p < 0.01, no such correlation was seen in the Non-ASD group (p = ns), or for paternal age in either group (p = ns).

            There was found to be an overall significant positive correlation between final diagnosis and maternal age, r(203)= 0.15, p < 0.05. This showed that older maternal age is associated with an ASD. No such correlation was found between final diagnosis and paternal age, r(178)= 0.04, p = ns. 

Conclusions: As seen in this sample of ASD versus non-ASD developmentally delayed children, the trend is that for the children with an ASD, the older the mother, the higher the IQ of the child and greater likelihood of ASD diagnosis. This trend was not observed in the non-ASD group. There was also found to be a significant positive correlation between receptive language scores and maternal age in the Non-ASD group that was not observed in the ASD group. Further studies need to be done to examine these relationships and their potential causes in more detail. Further implications will be presented in the poster presentation.