20596
Risk Factors for Autism Spectrum Disorder and Intellectual Disability
Objectives: 1.To explore the association between ART use and ASD 2. To explore the association between ART use and ID in individuals with ASD and their unaffected siblings 3. To explore the perinatal risk factors and other variables that may influence the development of ASD and ID
Methods: We used an online self-reported parental survey administered by Interactive Autism Network (IAN) to review the history of ART exposure in probands with ASD and their unaffected siblings. The sample size consisted of 1792 probands (mean age= 9.5 years, SD= 3.7, 82% male). Among them there were 1046 probands (58%) with ASD and 746 probands (42%) siblings without ASD (mean age= 8.7 years, SD= 4.4, 49% male).
Results: The prevalence of ASD was 64% among probands conceived through ART. Fisher’s exact test showed no statistically significant difference in these proportions. In order to explore what variables affect the prevalence of ASD, a series of logistic regression analyses with backward Wald deletion was conducted. The child’s gender and induced birth showed statistically significant effects on the prevalence of ASD. Males were 5.3 times more likely than females to show ASD (B=1.71, p<0.001) when several variables were controlled for. The children born with induced birth were 1.9 times more likely than those without induced birth to show ASD (B=0.662, p<0.05). Father’s age at birth had an insignificant but a positive effect on the prevalence of ASD; if the father’s age was older, the child was more likely to have ASD. In order to test whether or not the same variables used in the previous test had effects on intelligence quotient (IQ) score a series of logistical regressions were conducted. Babies conceived through ART were 8.5 times more likely to have low IQ (B=2.142, p<0.05). The children’s higher birth rate had a positive effect on lower IQ score (B=0.045, p< 0.05). The babies with lower birth weight were significantly more likely to have a lower IQ. The babies who had respiratory problems in the newborn period were 200 times more likely to have a lower IQ (B=5.302, p< 0.05). Girls were 14 times more likely to show lower IQ (B=-2.639, p< 0.05). Finally, older mothers were more likely to have a child with lower IQ (B=0.244, p<0.05).
Conclusions: There was no evidence that ART significantly increases the risk for ASD. ASD risk was significantly increased in males and in children who were born with induced birth and was also positively affected by the advanced paternal age. The risk for intellectual disability in both individuals with ASD and in their unaffected siblings was significantly increased by ART and by lower birth weight, prematurity, neonatal respiratory problems, female gender and older maternal age.