Media release

From: University of Otago

Greater mortality risk highlights urgent need for intervention – study

Young people with neurodevelopmental conditions face substantial and preventable health inequalities, a University of Otago – Ōtākou Whakaihu Waka-led study has found.

The project brought together a multidisciplinary team from universities and research organisations across the country, with significant leadership from disability researchers with neurodevelopmental conditions, ensuring lived experience was embedded throughout the research.

The Aotearoa New Zealand-first study found young people with a neurodevelopmental condition, such as autism, ADHD and intellectual disability, were nearly five times more likely to die before age 25 than those without a neurodevelopmental condition.

Lead author Dr Nick Bowden, of the Department of Paediatrics and Child Health, says while the relative risk is high, it is important to remember that deaths in this group remain rare, and the vast majority will lead long and healthy lives.

“This study provides an important foundation for shaping policies, services, and community actions that ensure all children and young people, regardless of neurodevelopmental condition, can live long, healthy, and fulfilling lives,” he says.

“What these findings highlight is the urgent need for targeted healthcare interventions, improved access to medical and mental health services, and systemic changes to address the social and structural barriers which contribute to health inequities.”

Published in high-profile journal JAMA Pediatrics, the study analysed the mortality risk among all people born in Aotearoa between 1995 and 2009.

It examined how risks varied by type of condition, sex, and cause of death, and what this might mean for health and disability services.

Using data managed by Stats NZ, it followed a total of 888,975 young people – until the end of 2019.  About 40,000 of them, or 4.5 per cent, had a neurodevelopmental condition. They were identified via hospital records, specialist mental health services, disability support databases, or through prescriptions.

Six main groups were studied: ADHD; autism; intellectual disability; specific learning and motor disorders; communication and language disorders; and fetal alcohol spectrum disorder.

The research team looked at recorded deaths and grouped them into three categories: medical causes (such as infections or chronic diseases), injuries (including accidents), and suicide.

Advanced statistical models were used to compare the risk of death between youth with and without neurodevelopmental conditions.

While mortality is still a rare outcome among young people, along with finding those with neurodevelopmental conditions were five times more likely to die before age 25, the study found the mortality risk was especially high among females, who were almost ten times more likely to die than females without neurodevelopmental conditions.

Risk also varied greatly by condition with those with specific learning and motor disorders having 8.5 times higher mortality; intellectual disability 8 times higher; communication and language disorders 6 times higher; autism 2.5 times higher; and ADHD about 2 times higher.

The causes of death also differed. For youth with any neurodevelopmental condition medical causes posed the greatest risk — about 12 times higher than for those without neurodevelopmental conditions, while injury-related deaths and suicide were almost twice as high.

Developmental paediatrician and co-author Dr Colette Muir says the higher risk of medical-related deaths points to challenges in managing co-occurring health problems – such as respiratory, neurological, and gastrointestinal conditions.

“There is opportunity for better identification and treatment for conditions that may reduce preventable deaths.”.

She describes the elevated rates of suicide and injury-related deaths as concerning, especially given New Zealand has one of the highest youth suicide rates among high-income countries.

Autistic Researcher and co-author Joanne Dacombe, also of Otago’s Department of Paediatrics and Child Health, says the findings call for better, targeted well-being, mental health, and crisis-support services, stronger suicide-prevention initiatives, and greater focus on environmental safety across all facets of life for young people with neurodevelopmental conditions.

“The study highlights the urgent need for improvements across all aspects of diagnosis and care for young people with neurodevelopmental conditions and further research to support this change,” she says

This includes early identification and intervention, especially in early childhood; integrated, multidisciplinary care across health, education, and disability services; equitable access to health and mental health support, particularly for groups facing structural barriers; training for clinicians and educators to improve awareness of neurodevelopmental conditions and reduce diagnostic overshadowing; community-led and culturally grounded approaches that recognise neurodiversity as part of human diversity.