CoChat
Sign Up
Cited by 399Autism Spectrum Disorder ResearchVaccine Coverage and HesitancyVirology and Viral Diseases

Pervasive Developmental Disorders in Montreal, Quebec, Canada: Prevalence and Links With Immunizations

Fombonne, Eric, Zakarian, Rita, Bennett, Andrew, Meng, Linyan, McLean-Heywood, Diane·2006·Pediatrics
DOI 10.1542/peds.2005-2993
Open this paper in CoChat — free account

Abstract

BACKGROUND. The prevalence of pervasive developmental disorders has increased in recent years. Links with the measles component of the measles-mumps-rubella vaccine and the cumulative exposure to thimerosal through other vaccines have been postulated. OBJECTIVES. The purpose of this work was to estimate the pervasive developmental disorder prevalence in Montreal, Canada, in cohorts born from 1987 to 1998 and evaluate the relationship of trends in pervasive developmental disorder rates with: (1) changes in cumulative exposure to ethylmercury (thimerosal) occurring through modifications in the immunization schedule of young children and (2) trends in measles-mumps-rubella vaccination use rates and the introduction of a 2–measles-mumps-rubella dosing schedule during the study period. METHODS. We surveyed 27749 children born from 1987 to 1998 attending 55 schools from the largest Anglophone school board. Children with pervasive developmental disorders were identified by a special needs team. The cumulative exposure by age 2 years to thimerosal was calculated for 1987–1998 birth cohorts. Ethylmercury exposure ranged from medium (100–125 μg) from 1987 to 1991 to high (200–225 μg) from 1992 to 1995 to nil from 1996 onwards when thimerosal was entirely discontinued. Measles-mumps-rubella coverage for each birth cohort was estimated through surveys of vaccination rates. The immunization schedule included a measles-mumps-rubella single dose at 12 months of age up to 1995, and a second measles-mumps-rubella dose at 18 months of age was added on after 1996. RESULTS. We found 180 children (82.8% males) with a pervasive developmental disorder diagnosis who attended the surveyed schools, yielding a prevalence for pervasive developmental disorder of 64.9 per 10000. The prevalence for specific pervasive developmental disorder subtypes were, for autistic disorder: 21.6 of 10000; for pervasive developmental disorder not otherwise specified: 32.8 of 10000; and for Asperger syndrome: 10.1 of 10000. A statistically significant linear increase in pervasive developmental disorder prevalence was noted during the study period. The prevalence of pervasive developmental disorder in thimerosal-free birth cohorts was significantly higher than that in thimerosal-exposed cohorts (82.7 of 10000 vs 59.5 of 10000). Using logistic regression models of the prevalence data, we found no significant effect of thimerosal exposure used either as a continuous or a categorical variable. Thus, thimerosal exposure was unrelated to the increasing trend in pervasive developmental disorder prevalence. These results were robust when additional analyses were performed to address possible limitations because of the ecological nature of the data and to evaluate potential effects of misclassification on exposure or diagnosis. Measles-mumps-rubella vaccination coverage averaged 93% during the study interval with a statistically significant decreasing trend from 96.1% in the older birth cohorts (1988–89) to ∼92.4% in younger birth cohorts (1996–1998). Thus, pervasive developmental disorder rates significantly increased when measles-mumps-rubella vaccination uptake rates significantly decreased. In addition, pervasive developmental disorder prevalence increased at the same rate before and after the introduction in 1996 of the second measles-mumps-rubella dose, suggesting no increased risk of pervasive developmental disorder associated with a 2–measles-mumps-rubella dosing schedule before age 2 years. Results held true when additional analyses were performed to test for the potential effects of misclassification on exposure or diagnostic status. Thus, no relationship was found between pervasive developmental disorder rates and 1- or 2-dose measles-mumps-rubella immunization schedule. CONCLUSIONS. The prevalence of pervasive developmental disorder in Montreal was high, increasing in recent birth cohorts as found in most countries. Factors accounting for the increase include a broadening of diagnostic concepts and criteria, increased awareness and, therefore, better identification of children with pervasive developmental disorders in communities and epidemiologic surveys, and improved access to services. The findings ruled out an association between pervasive developmental disorder and either high levels of ethylmercury exposure comparable with those experienced in the United States in the 1990s or 1- or 2-dose measles-mumps-rubella vaccinations.

Integrity signals

Registry

Crossref · 10.1542/peds.2005-2993

Cites

58 of 58 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

This paper’s full text isn’t openly available, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • No statistically significant difference was detected in the rate of increase in pervasive developmental disorder prevalence between the one-dose and two-dose MMR periods.

    “By comparing the rate of increase in PDDs prevalence between the one-dose and two-dose period, no statistically significant differences were detected.”

    From Vaccines for measles, mumps and rubella in children (2012) · cites this paper as Fombonne 2006

  • In the Montreal school-board cohorts born 1987 to 1998, MMR uptake significantly decreased while rates of pervasive developmental disorders significantly increased (OR 1.10; 95% CI 1.05 to 1.16; P < 0.001).

    “The authors reported that while a significant trend toward a decrease in MMR uptake through birth cohorts from 1988 to 1998 (X 2 for trend = 80.7; df = 1; P < 0.001) could be assessed, a significant increase in rates of PDDs from 1987 to 1998 was found (OR 1.10; 95% CI 1.05 to 1.16; P < 0.001).”

    From Vaccines for measles, mumps and rubella in children (2012) · cites this paper as Fombonne 2006

  • For more than a decade, a multitude of large-scale epidemiological studies have provided evidence refuting the notion that MMR vaccination causes ASD, including the role of vaccinations containing thiomersal in ASD etiology.

    “For more than a decade, a multitude of large-scale epidemiological studies have provided evidence refuting this notion [179, 180] including the role of vaccinations containing thiomersal in the ASD etiology [181].”

    From The contribution of environmental exposure to the etiology of autism spectrum disorder (2019) · cites this paper as [180]

Cites

1 retracted

Flagged first, then by citations

Cited by

Sorted by citations

Related

Authors
Fombonne, E., Zakarian, R., Bennett, A., Meng, L., & McLean-Heywood, D.
Affiliations
  • Montreal Children's Hospital (CA)
  • Lester B. Pearson School Board, Montreal, Quebec, Canada
Corresponding author
Fombonne, Eric
ORCID
Fombonne, Eric
Venue
Pediatrics
Publisher
American Academy of Pediatrics (AAP)
Published
2006-07-01
Volume
118
Issue
1
Pages
e139-e150
ISSN
  • 0031-4005 (ISSN-L)
  • 1098-4275
DOI
10.1542/peds.2005-2993
OpenAlex
W2140996251
Cited by
399
References
58
Citations by year
2026: 3 · 2025: 7 · 2024: 1 · 2023: 27 · 2022: 8 · 2021: 9 · 2020: 10 · 2019: 13 · 2018: 10 · 2017: 17 · 2016: 11 · 2015: 21 · 2014: 21 · 2013: 26 · 2012: 28
FWCI
18.61
Type
journal article
Language
en
Open access
closed
Locations
  • PEDIATRICS (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • McGill University
  • Canada Research Chairs
  • Canadian Institutes of Health Research
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Autism Spectrum Disorder Research
  • Social Sciences › Health › Vaccine Coverage and Hesitancy
  • Health Sciences › Medicine › Epidemiology › Virology and Viral Diseases
Keywords
pervasive developmental disorders, autism spectrum disorder, Asperger syndrome, pervasive developmental disorder not otherwise specified, thimerosal, MMR vaccine, measles vaccine, vaccination schedule, vaccine safety, Montreal, birth cohort, school-based screening, special needs services
MeSH terms
Adolescent, Autistic Disorder, Child, Child Development Disorders, Pervasive, Child, Preschool, Ethylmercuric Chloride, Female, Humans, Immunization, Immunization Schedule, Male, Quebec, Thimerosal, Prevalence, Logistic Models, Age Distribution, Sex Distribution, Asperger Syndrome, Measles-Mumps-Rubella Vaccine

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review