Exploring the life expectancy of autistic individuals in the U.K.

By Dr. Priyom Bose, Ph.D.Reviewed by Benedette Cuffari, M.Sc.Nov 29 2023

A recent The Lancet Regional Health - Europe study estimates the life expectancy of autistic people living in the United Kingdom.

Study: Estimating life expectancy and years of life lost for autistic people in the UK: A matched cohort study. Image Credit: SewCreamStudio / Shutterstock.com

Diagnostic services and support for autism

Autism is an incurable neurodevelopmental condition that affects an individual’s communication skills and interactions. Moreover, an autistic person often finds it difficult to understand the feelings or thoughts of another person.

Some of the common diagnostic criteria for autism include restricted and repetitive patterns of behaviors, activities, and interests. The lack of social communication and interactive capacity are two other vital determining traits of autism.

As compared to the general population, people diagnosed with autism are more likely to experience co-occurring neurodevelopmental challenges, such as attention deficit hyperactivity disorder (ADHD), epilepsy, intellectual disability (ID), and cerebral palsy, as well as hearing and visual impairments. A higher prevalence rate of poor physical and mental health conditions has also been recorded in the autistic population.

Autism is referred to as a spectrum condition where varying degrees of support are needed by affected individuals. Typically, younger people receive a higher autism diagnosis than older people, which is due to the greater amount of diagnostic services that have been provided to children and younger people over the past several years. Nevertheless, one survey revealed that autism prevails across all age groups at similar rates; therefore, many adults remain undiagnosed.

In the U.K., autism diagnostic assessment services for adults remains poor. A recent report indicated that approximately nine out of 10 autistic individuals over 50 years of age in England remain undiagnosed.

Adults who receive a diagnosis of autism are often middle-aged, older, and require support. On average, the amount of support required for diagnosed autistic people is higher than for those who are undiagnosed.

Life expectancy of autistic people in the U.K.

Previous studies have shown that people diagnosed with autism are more likely to die prematurely. However, this observation has been based on the average death for a small proportion of autistic and control group samples.

The U.K. Office for National Statistics (ONS) has adopted a superior methodology known as the life table method to estimate the life expectancy of autistic people as compared to the non-autistic population. This methodology involves estimating the mortality rate of each year of age based on the number of deaths in each age group. The age-specific rates are used to calculate life expectancy.

In the current study, the life expectancy of the autistic population was estimated using the U.K. primary care electronic health records from IQVIA Medical Research Data (IMRD). IMRD comprises 794 U.K. primary care practices that constitute over 18 million individuals, which is considered a true representation of the U.K. population. Typically, diagnoses made in secondary care, including autism, are communicated through a primary care practitioner (GP).

The current study involved two cohorts including autistic people with ID and autistic people without ID. An exposure density sampling method was used to identify matched comparison candidates who were selected based on age, sex, and without autism.

A total of 17,130 participants diagnosed with autism without ID were selected and matched with 171,300 participants. Likewise, 6,450 participants diagnosed with autism and ID were included and the study and matched with 64,500 healthy participants. 

Unlike previous studies that indicated around sixteen years of less survival time due to autism, the current study estimated the years of life lost due to autism without ID to be approximately six years. However, the approximate years of life lost in women and men diagnosed with both autism and ID were 15 and seven years, respectively. Since only a small number of people were diagnosed with autism in the study cohort, most of whom were young, it led to a reflection of a smaller number of deaths.

Based on these estimates and previous epidemiological studies, a higher life expectancy prevails in autistic people without ID. Only one in 10 people who fit the current diagnostic criteria were actually diagnosed with autism.

The study findings highlight that autism diagnostic records were absent from the database due to the lack of an autism diagnosis. This observation indicates that autistic adults who require less support and work in the community are often left undiagnosed.

Conclusions

The life expectancy deficit for autistic people without ID was significantly lower than the previous estimation of 16 years of less survival. Based on the support required, co-occurring neurodevelopmental issues, physical and mental health conditions, those who have better contact with autistic services are more likely to receive proper diagnosis.