In total, 40.6 % of invited mothers consented to participate.The cohort comprises 114,500 children and 95,200 mothers.
to establish an overall measure for presence of autistic-like behavior.
The ASD sample in the present study does not reflect the true national prevalence rate of ASD, as the present study due to the fact that not all children in Norway participated, and that all children with missing responses on the M-CHAT were excluded.
At the same time, new cases of ASD will be diagnosed with increasing age and subsequently listed in NPR (Súren et al. Children in the current sample were born between 20 and at the linkage to NPR, autumn 2014, the youngest children in the sample were still only 5 years of age.
) suggested ASD could be considered an extreme expression of normal male, compared to female, phenotypic profiles.
In this paper, sex-specific M-CHAT scores from N = 53,728 18-month-old toddlers, including n = 185 (32 females) with ASD, were examined.