Is Autism More Common Now than Ten Years Ago?

Abstract

A total population study of children, aged 13 years and under, suggested that there has been an apparent rise in the frequency of autistic disorder and autistic-like conditions (excluding Asperger's syndrome) in one area of western Sweden over the last ten years. The frequency was 4.0/100,000 in 1980, 7.5/10,000 in 1984 and 11.6/10,000 in 1988 in the city of Göteborg. Even though the prevalence rates refer to slightly different age cohorts, it was concluded that the apparent increase is in part due to better detection, but also to new cases born to immigrant parents. Typical cases of autistic disorder accounted for 75% of cases, and 20% had normal or near-normal IQs.

CHARGE association in Sweden: Malformations and functional deficits

“…The speech difficulties could be explained by severe hearing impairment, tracheostomy and cleft palate, and learning disability and autism also affected the ability to communicate. The rate of autism in the general population is about 1-2 in 1000 [Bryson et al, 1988;Gillberg et al, 1991;Gillberg and Wing, 1999;Wing and Potter, 2002]. Our data suggest that autism/atypical autism is much more common in CA than in the general population given that 40% of our comprehensively examined subjects met the criteria for autism/atypical autism.…”

Advancing paternal age and risk of autism: new evidence from a population-based study and a meta-analysis of epidemiological studies

“…Two epidemiological surveys of autism prevalence that applied robust case-ascertainment methods were conducted in western Sweden during the early and late years of the birth-cohort (37,38). The prevalence rates reported in those surveys (5.6 and 9.1 per 10,000, respectively) are similar to those in the national register, supporting the registry's representativeness.…”

Epidemiological trends in rates of autism

“…11 The same applies to the third approach, which compared rates estimated in repeat surveys in the same geographical area. 12 A fourth approach tested the hypothesis of a secular increase in comparing rates in successive birth cohorts surveyed with rigorously comparable methods, but no statistical difference in rates was found. 13 Finally, the fifth approach is represented by two recent incidence studies 14,15 which both showed increased incidence rates in the early 1990s.…”