Life expectancy lags for autistic people in United Kingdom

Autistic people without intellectual disability live about six years less, on average, than non-autistic people do, according to a study in the United Kingdom.

The findings confirm past research linking autism to early death but suggest that the life expectancy gap may be smaller than previously thought.

“The reason we wanted to look at life expectancy was that there is a widely quoted statistic that autistic people live 16 years less on average, which was quite frightening,” says lead investigator Joshua Stott, professor of aging and clinical psychology at University College London.

That statistic comes from a 2018 Swedish study that compared the average age at death for more than 27,000 autistic people and 2.6 million gender- and age-matched non-autistic people, using data from the country’s National Patient Register and Cause of Death Register. But that approach may have underestimated autistic people’s lifespan, because many elderly adults are undiagnosed, Stott says.

Instead, he and his colleagues used electronic primary care health records from January 1989 to January 2019 to identify 17,130 thousand autistic adults without intellectual disability and 6,450 autistic adults with intellectual disability. They matched each autistic person with 10 non-autistic people of the same age and sex, and with comparable intellectual abilities, from the same primary care practice. They then estimated overall life expectancy at age 18, based on mortality rates they calculated for both biological sexes across every single year of age.

 

 

Autistic men and women without intellectual disability live to an average age of about 75 and 77, respectively, the estimates suggest. By contrast, non-autistic men and women live to about age 81 and 83.

Life expectancy lags even further for autistic people with intellectual disability: Autistic men in this group live to about age 72, which is 7 years less than non-autistic men with intellectual disability. And autistic women in this group live to age 70, which is 14 years less than non-autistic women with intellectual disability.

But because women have historically been underdiagnosed with autism and the study included only 1,600 autistic women with intellectual disability, their estimated life expectancy should be interpreted with caution, Stott says.

T

he study and the statistics are neatly done, says Jack Underwood, a clinical research fellow at Cardiff University. But the findings may not be representative of all autistic people, because recent evidence suggests that most autistic people in England lack a formal diagnosis, he adds.

And bias could skew the results in either direction, according to the study: Those who have an autism diagnosis could have more autism traits than those who don’t, in which case the findings could overestimate the life expectancy gap. On the other hand, those with a diagnosis could have more access to medical care, leading to an underestimate of the life expectancy gap.

Either way, the study shouldn’t be interpreted as providing a definitive estimate of autistic people’s life expectancy, says Jessica Eccles, reader in brain-body medicine at Brighton and Sussex Medical School. “But this is the best we’ve got at the moment.”

The source of the life expectancy gap remains unclear, but it’s not necessarily the autism itself, she adds. Autistic people are more likely than non-autistic people to experience other health issues, including immune, gastrointestinal, sleep and mental health conditions. “Being autistic per se is a risk factor for health inequalities,” she says.

And although the life expectancy gaps in the new study are smaller than those in previous reports, it is still worrying, Stott says. “Even if it’s a small proportion, it’s still a proportion. Six years is a long time.”