A recent epidemiological study investigates the link between autism and mortality.

Autism spectrum disorders (ASD) are characterized by a difficulty with social interactions, communication problems, and repetitive behaviors. They are estimated to affect around 1 in 68 children.

Above and beyond the symptoms of ASD, individuals with a diagnosis have substantially shorter lives; they die, on average, 36 years earlier than the general population at an average age of 36, compared with 72.

Although the reduced lifespan of individuals with ASD has previously been noted, little research has specifically investigated data regarding injury mortality.

A group of researchers from Columbia University Mailman School of Public Health in New York undertook an epidemiological study to fill this gap in our understanding. Led by Dr. Guohua Li, a professor of epidemiology, the team delved into data from the United States National Vital Statistics System. In all, they screened 32 million death certificates.

Autism epidemiology data

They identified 1,367 individuals with an ASD diagnosis who died between 1999 and 2014, comprising 1,043 males and 324 females.

The data showed that the annual number of deaths for people with an ASD diagnosis had risen nearly sevenfold in the 15 years from 1999 to 2014.

Dr. Li, who is the founding director of the Center for Injury Epidemiology and Prevention at Columbia, said of the results: "Despite the marked increase in the annual number of deaths occurring, autism-related deaths still may be severely underreported, particularly deaths from intentional injury such as assaults, homicide, and suicide."

Of the registered deaths, 28 percent were due to injury, the most common of which was suffocation. This was followed by asphyxiation, then drowning. In fact, those three causes accounted for almost 80 percent of total injury mortality in children with ASD. More than 40 percent of these incidents occurred at home or in residential institutions.

The study's findings, published this week in the American Journal of Public Health, are worrying:

"Our analysis reveals that children with autism are 160 times as likely to die from drowning as the general pediatric population. Given the exceptionally heightened risk of drowning for children with autism, swimming classes should be the intervention of top priority."  Dr. Guohua Li

Drowning and autism

When asked why drowning should be such a common cause of death for individuals with ASD, Dr. Li says: "With impaired communication and social skills, autistic kids tend to seek relief of their heightened anxiety from the serenity of water bodies. Unfortunately, this behavior too often leads to tragedies."

Children are often diagnosed with ASD at the age of 2 or 3. At this point, Dr. Li says that "pediatricians and parents should immediately help enroll the child in swimming classes, before any behavioral therapy, speech therapy, or occupational therapy." He continues: "Swimming ability for kids with autism is an imperative survival skill."

Although the research used a great deal of data, there are some gaps in the results. Joseph Guan, the lead author and a student in epidemiology at Columbia University Mailman School of Public Health, says: "Our study was limited to death certificate data. While the numbers are startling, autism as a contributing cause of death is likely undercounted because [...] the accuracy of information on death certificates filed by coroners varies."

Despite the shortfalls in the study's data, the findings and conclusions are likely to influence recommendations for the parents of children with ASD. Something as simple as swimming lessons really could be a life-saver for some children.