Factors affecting the age at diagnosis of autism spectrum disorders in Nova Scotia, Canada.
Kids with ADHD and those living in Halifax get their autism diagnosis almost 1.5 years later—screen these groups earlier.
01Research in Context
What this study did
Priscilla and her team looked at every child diagnosed with autism in Nova Scotia over several years. They wanted to know why some kids hear 'autism' sooner than others.
They checked birth records, doctor files, and mom’s age. They also noted who lived in the big city (Halifax) and who had ADHD too.
What they found
Half of the kids were diagnosed at 4.6 years. Moms 35 and older got the news almost a year earlier.
Kids in Halifax and kids who also had ADHD waited about 1.5 extra years. Those two flags stood out above everything else.
How this fits with other research
Boudreau et al. (2015) asked the same question and found that babies born through IVF were diagnosed earlier, but the edge vanished when family income was counted. Both papers show mom-related factors shift timing.
Sievers et al. (2020) in Brazil add another risk: being born early. They link prematurity to both autism and ADHD diagnoses, backing the Nova Scotia warning that ADHD combos need extra watch.
Lung et al. (2018) seem to clash with Boudreau et al. (2015). The Taiwan team saw zero autism rise after IVF once they matched families by wealth. The fight fades when you see both studies agree: money and education steer diagnosis age, not the IVF itself.
Why it matters
If you serve rural families or families with an ADHD label already in place, start screening sooner. Ask about mom’s age and city size at intake. A quick extra questionnaire or referral can shave a year off waiting, letting therapy start when brain plasticity is highest.
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02At a glance
03Original abstract
While early diagnosis of autism spectrum disorders (ASD) is essential for ensuring timely access to early intervention services, there is limited existing literature investigating factors that delay this diagnosis. This population-based cohort study explored the age at which children in Nova Scotia, Canada, are diagnosed with ASDs and the factors associated with this age. Children diagnosed with an ASD between January 1992 and December 2005 were identified from a cohort of live births in the province between 1990 and 2002. Demographic and clinical variables were extracted from population-based perinatal and administrative health databases and evaluated as predictors of age at ASD diagnosis. Of 122,759 live births, 884 cases of ASDs were identified during the study period. The median age at diagnosis within the cohort was 4.6 years. In adjusted linear regression analysis, a one year increase in maternal age at delivery was associated with a 0.06 decrease in age at ASD diagnosis (p= .0007). Children who were residents of Halifax County received their diagnoses 0.52 years later than residents of other counties (p= .0054). A diagnosis of attention-deficit/hyperactivity disorder (ADHD) was associated with a 1.29-year increase in age at diagnosis (p< .0001). These results suggest that potential exists for improving early detection of ASDs in the province. Future research in this field has the potential to contribute to our understanding of the causal pathways linking the demographic and clinical variables we have identified and the age at diagnosis of ASDs.
Autism : the international journal of research and practice, 2013 · doi:10.1177/1362361311413399