Age at autism diagnosis in the Norwegian Mother, Father and Child Cohort Study (MoBa): exploring the association with family wellbeing.

For many autistic individuals, close family members represent a crucial source of support throughout their lifetime. Early diagnosis of autism is thought to benefit to both autistic individuals and their family members by facilitating early access to services and information. However, little research has empirically studied the relationship between age at diagnosis and wellbeing among individuals with autism and their family members. In this study, we examined predictors of age at autism diagnosis and its relationship with family wellbeing using the population-based Norwegian Mother, Father, and Child cohort study (MoBa). We found that the most important factors associated with a later age at diagnosis were fewer social communication difficulties at age 3, fewer maternal concerns about development in early childhood, the absence of a co-occurring intellectual disability diagnosis, female sex, and having older siblings . We also found that a later age at diagnosis is associated with higher wellbeing for mothers and children during childhood, whereas it is associated with lower wellbeing for children during adolescence. Importantly, all associations were substantially attenuated after adjustment for a range of clinical, demographic, and genetic factors – reflecting the complex patterns of confounding that influence observed relationships between age at diagnosis and family wellbeing. We argue that future research should aim to leverage public awareness campaigns, screening programmes, or changes in clinical practice to understand the causal mechanisms underlying these relationships.