Assessing autism prevalence

Autism spectrum disorder has a global prevalence of 1% to 2% of the population. Very little research has been done in the non-White population, which could have an impact in planning a variety of services. An investigation in JAMA Pediatrics looked at the prevalence of autism spectrum disorder in the English state school population.¹

The investigators performed a case-control prevalence cohort study, which used the Spring School Census 2017 from the Pupil Level Annual Schools Census of the National Pupil Database. This data encompasses all children, teenagers, and young adults aged 2 to 21 years who are in state-funded education. There are 2 levels of support that a child may receive: SEND support, which are school-specific learning programs given to pupils and Education, Health and Care Plans, which were introduced as part of the Children and Families Act 2014.

The population included a total of 7,047,238 pupils. In this cohort, there were 119,821 pupils with autism spectrum disorder, of which 21,660 had learning difficulties. The investigators found that the standardized prevalence of autism spectrum disorder was 1.76% (95% CI, 1.75%-1.77%), with female pupils having a prevalence of 0.65% (95% CI, 0.64%-0.66%) and male pupils having a prevalence of 2.81% (95% CI, 2.79%-2.83%), creating a male-to-female ratio (MFR) of 4.32:1. Black pupils had the highest standard prevalence (2.11% [95% CI, 2.06%-2.16%]; MFR, 4.68:1). Pupils who had autism spectrum disorder were more likely to speak English as an additional language (adjusted prevalence ratio, 0.64; 95% CI, 0.63-0.65) as well as face social disadvantages (adjusted prevalence ratio, 1.61; 95% CI, 1.59-1.63).

The investigators concluded that there were significant differences in autism spectrum disorder prevalence across not only racial/ethnic groups, but geographic areas and local districts. These findings are in line with research that found higher rates of autism spectrum disorder in immigrants with foreign-born mothers in United States, but contrast with other studies that indicate lower rates in the Black community and people with a lower socioeconomic status. The investigators believe that their results highlight the need to have a better understanding of who gets a diagnosis, when they get it, what support is offered, and how much social determinants of health impact autism spectrum disorder status.

Reference

1. Roman-Urrestarazu A, van Kessel R, Allison C, Matthews F, Brayne C, Baron-Cohen S. Association of race/ethnicity and social disadvantage with autism prevalence in 7 million school children in England. JAMA Pediatr. 2021;175(6):e210054. doi:10.1001/jamapediatrics.2021.0054