Research also uncovers an overlap with ultra-processed foods, sugary drinks, mental health, screen time, smoking and alcohol.
New research just out shows that almost half (45.6%) of Australian teens are living with chronic diseases or developmental conditions like attention deficient hyperactivity disorder (ADHD) or autism (ASD). The study has linked the conditions to unhealthy lifestyles, diets, and poor mental health, prompting calls for further research and government action.
The study, published in the Australian and New Zealand Journal of Public Health on 2 April, 2025 involved a survey of over 5,000 Australian adolescents.
It is the first study of its kind in Australia to examine six unhealthy behaviours and mental health, while examining their overlap with common and emerging health conditions in teens such as irritable bowel syndrome (IBS), asthma, eczema, chronic fatigue, hay fever, food allergies, type 1 / type 2 diabetes, ADHD and ASD.
Lead author Dr Bridie Osman from the Matilda Centre for Research in Mental Health and Substance Use at the University of Sydney, says that the issue of chronic disease and developmental conditions in teenagers is often overlooked as a serious public health concern.
“Alarmingly this study shows that one in two Australian teenagers are living with a chronic disease or developmental condition,” Dr Osman said.
“These conditions can have a profound impact. They can hinder a teenager’s ability to attend school or sports and can have social and developmental implications. Some of these chronic health conditions can also cause ongoing damage to the immune system and contribute to more severe diseases in later life.
This finding is a wake-up call that we need to do more to prioritise the health of young people.
Researchers found that the most common chronic diseases in teenagers were hay fever (23%) and asthma (15%), whilst the most common developmental condition was ADHD, affecting 9% of participants.
The study found that overall, teenagers who were female, consumed more ultra-processed foods, sugar sweetened beverages, alcohol, spent more time on screens or had a mental health condition were more likely to have at least one chronic disease or developmental condition.
But that doesn’t mean males aren’t at risk. It was teenage males who had a disproportionally higher risk of having disease when they had a mental health condition, when compared with females who had the same mental health conditions.
Dr Osman pointed out that whilst the study could not demonstrate that diseases and conditions were caused by unhealthy lifestyles, there was a clear link that is important and requires further investigation.
“When looking at each of the diseases and conditions individually, we found that consuming more ultra-processed food, alcohol and smoking tobacco and having poorer mental health was linked to every one of the different diseases and conditions we measured.
“While previous research has proven the cause of some of these relationships, we need to do more long-term research to get a clearer understanding of the causes behind all these common and emerging diseases and development conditions in teenagers so we can prevent them.
In the meantime, we need to ensure a whole-of-lifestyle approach when preventing and treating these diseases.
“What we do know is that all teenagers’ immune health will benefit from healthy diets, exercise, sleep, reducing screen time and good mental health.”
Adjunct Professor Terry Slevin, CEO, Public Health Association of Australia said that this was a significant study with important findings, particularly when it comes to warnings around the increasing deterioration of young people’s diets.
“This large study offers a warning of the health impacts of unhealthy diets. The intake of ultra-processed foods amongst teens is at an all-time high and obesity has recently overtaken tobacco as Australia’s biggest cause of preventable disease.”
“We need to do more to help all Australians, particularly teenagers, choose the right foods to set them up for good physical and mental health.”
“We also need to stop children from being bombarded with unhealthy food advertising, mandate health star ratings on packaged foods, and increase awareness of the benefits of a good healthy diet.”
SOURCE: Australian and New Zealand Journal of Public Health/Public Health Association of Australia
