Trends in Autism Spectrum Disorders Incidence Among Children Born in Israel during 1992-2009: A Total Population Study

Background: The reported prevalence and incidence of autism spectrum disorders (ASD) are increasing worldwide. Diagnosis shifts, earlier age at diagnosis and clinical criteria, as well as environmental factors were suggested as explanations for this increase. Ascertainment of ASD is most probably influenced to a great extent by socio-demographic and cultural factors. These conditions limit the ability to conclude whether a real increase in incidence exists.

Objectives: Describe the incidence of ASD and its time trends in the total population of Israeli children born 1992-2009 by population group, and the prevalence of ASD in Israel by age 8 years.

Methods: We analyzed data from the records of the Israeli National Insurance Institute, a governmental welfare organization which tracks all Israeli residents. Case status was based on confirmation of unique child disability benefit due to ASD. The study population for incidence purposes consisted of all children born in Israel 1992-2009.

Results: Overall, 9,109 ASD cases among 2,431,649 children were included in the study.  By 2011, ASD prevalence at age 8 was 0.49% (one in 203 children), but differed substantially by population group, with Israeli Arabs having 0.10%, Ultra-orthodox Jews with 0.30% and the general population with 0.76% (1.27% in boys, 0.23% in girls). There was a steep and consistent increase in ASD incidence with advancing birth cohorts born 1992-2004, stabilizing among those born 2005-2009. ASD cumulative incidence by age 8 years increased 10-fold during 1992-2003, from 0.049% to 0.49%. The trend for Israeli Arabs was different, with a later rise in incidence, only for birth cohorts born 2001-2009.

Conclusions: ASD incidence in Israel is rising, in accordance with worldwide trends. The segregation of rising incidence time trends by ethnic groups in Israel is compatible with a gradual process of increased awareness of medical staff, educational staff and the general public.