Individuals with autism may die up to 30 years earlier than those without the disorder, new research finds.
Autism spectrum disorder (ASD) is a developmental condition characterized by repetitive behaviors and problems with social interaction and communication. Other symptoms of ASD include learning difficulties, a short attention span, aggression and hyperactivity.
In the US, around 1 in 68 children are diagnosed with ASD, with the condition around five times more common among boys than girls.
Previous research has found a link between ASD and increased risk of premature death, but the study researchers - including Prof. Sven Bölte, head of the Centre of Neurodevelopmental Disorders at Karolinska - note that such studies have been too small to effectively compare mortality between individuals with low- and high-functioning ASD.
"Thus, the potentially moderating effect of intellectual disability in mortality and causes of death in ASD remain unclear, and it has not been possible to determine whether ASD per se carries an increased mortality," they note.
Premature death risk 2.5 times higher for people with autism
To investigate further, the team analyzed data from two Swedish population-based registers, which included 27,122 people with ASD - of whom around 6,400 had intellectual disability - and more than 2.6 million controls, who were matched for age, gender and county of residence.
The researchers assessed the rate of all-cause and cause-specific mortality among all individuals.
They found that, on average, individuals with ASD have a 2.5 times higher risk of premature death than the general population.
In detail, the team found that individuals with autism die an average of 18 years earlier than those without the condition, while those with autism and intellectual disability die around 30 years earlier, with epilepsy identified as the leading cause of death among this group.
For individuals with autism with no intellectual disability, suicide was found to be the leading cause of death.
UK-based charity Autistica have created a report largely based on the team's findings, in which they say the study "confirms the true scale of the hidden mortality crisis in autism."
Commenting on the results, Jon Spiers, chief executive of Autistica, says:
"The inequality in outcomes for autistic people shown in this data is shameful. We cannot accept a situation where many autistic people will never see their 40th birthday.
Everyone involved in supporting people on the autism spectrum from the Government right down to local care providers has a responsibility to step up and start saving lives as soon as possible."
While the study researchers are unable to pinpoint exactly why people with autism are at greater risk for premature death, they and the authors of the Autistica report hypothesize that it may be down to lifestyle, social and psychological factors.
For example, individuals with autism can have a more restricted diet, reduced access to exercise and be subject to social isolation and bullying. They are also at greater risk for anxiety and depression and may experience problems accessing health care.
The researchers note that future studies should focus on identifying the underlying factors that drive premature death for people with autism.
Earlier this year, Medical News Today reported on a study linking maternal obesity and diabetes to increased risk of autism in offspring.