Research out of Sweden reveals that adults diagnosed with autism spectrum disorder die 16 years earlier than their counterparts. Suicide is one major cause.

When Wendy Fournier first saw the numbers, she said it was a “real kick in the gut.”

A study out of Sweden completed late last year revealed that people with autism died an average of 16 years earlier than those without the condition.

It also revealed that the leading causes of death in people with autism were heart disease, suicide, and epilepsy.

Fournier is president of the National Autism Association and also has a 16-year-old daughter with severe autism.

The results of the study stunned her. “It really rocks you,” Fournier told Healthline. “It was startling to see all that in print.”

Fournier said the information has motivated her organization and other groups to push for more research on the effects and treatment of autism.

“We need to dig deeper,” she said. “We need to treat autism as a whole body disorder.”

Read more: Brain Chemical Doesn’t Do Its Job in People with Autism »

The study findings were recently published in the British Journal of Psychiatry.

It’s the first time definitive research has been done on the mortality rate of people with autism.

Fournier said that’s because until two decades ago autism diagnosis was uncommon and it was considered a disorder that only affected children.

Now, researchers have the opportunity to follow a significant number of adults with autism. “It lets us see what happens to [people with autism] as they get older,” said Fournier.

Between 1987 and 2009 scientists from the Karolinska Institute looked at more than 27,000 people in Sweden diagnosed with autism spectrum disorder (ASD).

This group was compared with a group of 2.6 million people without ASD.

During that time, less than 1 percent of the general population died. The mortality rate for the group with ASD was 2.5 percent.

What the researchers also discovered was that average life expectancy for the general population was about 70 years old. In the ASD group, the average age was about 54.

Perhaps more startling, people with ASD that also had cognitive disabilities had an average life expectancy just under 40 years old.

Read more: Does an ADHD Diagnosis Camouflage Autism? »

The researchers reported suicide was one of the leading causes of early death among people with ASD.

In fact, the researchers concluded suicide rates of people with ASD who had no cognitive disability were nine times higher than the general population.

Previous studies had shown that 30 percent to 50 percent of people with ASD have considered suicide, according to a report issued last week by the nonprofit organization Autistica.

The suicide rate is higher among girls with ASD and people with milder forms of the condition.

The experts said that’s because this group are more aware of their condition and possible difficulties assimilating.

In addition, bullying can be a daily occurrence for people with ASD. Anxiety and depression are common responses to such treatment. Both of those mental health stresses are leading factors in suicide.

“This is the emotional cost of being excluded from society,” Steve Silberman, the author of “NeuroTribes: The Legacy of Autism and the Future of Neurodiversity,” told Healthline.

The Swedish researchers also noted that epilepsy is common among people with ASD and the likelihood of developing it increases with age.

The researchers estimated 20 to 40 percent of people with ASD also have epilepsy compared with 1 percent of the general population.

People with ASD and cognitive disabilities, the researchers added, are 40 times more likely than the general population to die prematurely from a neurological condition.

In their report, Autistica officials recommended more research be done to establish the relationship between autism and epilepsy.

Read more: Using Antidepressants During Pregnancy Increases Autism Risk »

The general population, according to the Autistica report, also tends to have better overall health than people with ASD.

People with ASD may experience a variety of medical problems, such as gastrointestinal disorders. However, one of the most common is heart disease.

There’s no scientific evidence to explain why this condition is so common with autism, but Fournier says stress may have a lot to do with it.

Bullying may lead to feelings of alienation. Other people with ASD may experience sensory overload and sensitivity to noise and bright light.

The stress of engaging with other people or going on a job interview may also be overwhelming.

“For many, normal social situations are an acting job,” Dr. Janet Lintala, the author of “The Un-Prescription for Autism” and the mother of a 21-year-old son diagnosed with autism, told Healthline.

Fournier said this daily burden of social awkwardness and physical ailments takes a toll mentally and physically.

“They suffer from lifelong stress and anxiety,” she said.

“It’s almost like this perfect storm that follows them,” added Lintala. “They’re wired into a constant state of flight or fight.”

That, both women said, can lead to physical ailments, including heart disease, brain inflammation, strokes, and diabetes.

Read more: Boy with Autism Improves on Antibiotics, Connecting Gut Bacteria to ASD »

The report has prompted autism activists to urge those in the medical community, as well as the general population, to change how they view and treat ASD.

“The report is a very definitive indictment of how we treat autistic people and their families,” said Silberman.

Autistica officials have started a fundraising campaign to raise money for awareness, research, and treatment.

“The inequality in outcomes for autistic people shown by this data is shameful, but we must not forget the real individuals and families behind these statistics,” Jon Spiers, chief executive of Autistica, wrote in his organization’s report.

The crusade would impact a lot of people. Autism now affects 1 in every 68 children in the United States and that percentage is growing rapidly, according to the National Autism Association’s website.

Fournier would like to see the focus of research and treatment shifted to treating the entire spectrum of challenges autism brings as well as the effects in adulthood.

“A lot of symptoms are completely ignored,” she said, “and that leads to a lifetime of pain.”

Silberman agrees. He would like to see some emphasis shifted away from trying to find the causes of autism and put more energy toward helping people already diagnosed.

“We’re not going to find a magic bullet on what produces autism,” he said. “We need to look at what we can do to improve the quality of life for people with autism. The cost of not doing so is death.”