Premature mortality in a population-based cohort of autistic adults in Canada

Research from different countries suggests that autistic adults are more likely to die prematurely than non-autistic adults, but these studies do not always investigate male and female individuals separately and do not consider whether this pattern is unique to autistic people or is also an issue for people with other developmental disabilities. We examined premature mortality in autistic males and females (assigned at birth) in a population-based cohort, compared to males and females with and without other developmental disabilities. Using linked administrative health and social services population data from Ontario, Canada, age-matched males and females aged 19-65 years were followed between 2010 and 2016, and causes of death were determined. Over the 6-year observation period, 330 of 42,607 persons (0.77%) in the group without developmental disabilities had died compared to 259 of 10,646 persons (2.43%) in the autism group and 419 of 10,615 persons (3.95%) in the other developmental disabilities group. Autistic males and females were more likely to die than non-autistic males (adjusted risk ratio, RR 3.13, 95%CI 2.58-3.79) and non-autistic females (adjusted RR 3.12, 95%CI 2.35-4.13) without developmental disabilities, but were less likely to die than adults with other developmental disabilities (males: adjusted RR 0.66, 95%CI 0.55-0.79; females: adjusted RR 0.55, 95%CI 0.43-0.71). Most common causes of death varied depending on a person's sex and diagnosis. Given the greater likelihood of premature mortality in adults with developmental disabilities including autism, greater attention and resources directed toward their health and social care are needed, tailored to their sex and diagnosis-informed needs. Lay Summary This study looked at how many autistic men and women died over 6 years (2010-2016), along with how they died, and compared this to adults who did not have autism living in Ontario, Canada. It found that autistic men and women were more than three times as likely to die as people of the same age who did not have a developmental disability. However, adults with other developmental disabilities besides autism were even more likely to die than autistic adults. This means that we have to pay more attention and invest in better social and health care for autistic people, along with people who have other types of developmental disabilities.