Mayo Clinic study suggests no link between autism and immunizations

Over the past 20 years, there has been speculation about a connection between immunizations and an increase in autism. However, a study by Mayo Clinic researchers published in the January issue of Archives of Pediatrics and Adolescent Medicine suggests the increase may be due to improved awareness, changes in diagnostic criteria and availability of services, not environmental factors or immunizations.

“This study is the first to measure the incidence — the occurrence of new cases — of autism by applying consistent, contemporary criteria for autism to a specific population over a long period of time,” says William Barbaresi, M.D., a Mayo Clinic developmental pediatrician and one of the study authors. “In doing so, the study accounts for improvements in the diagnostic criteria for autism, the medical community’s improved understanding of this disease and changes in federal special education laws.”

The study found that the increase in the incidence of autism in Olmsted County, Minn. coincided with broadening of the diagnostic criteria for autism and new federal special education laws including autism as a disability category. Both events occurred many years after immunizations were mandated for school entry. Broader, more precise diagnostic criteria for autism were introduced in 1987. Prior to these new criteria, children with autism may have been given less precise diagnoses such as “developmental delay” or “mental retardation,” and children with milder symptoms of autism may not have been identified at all. The 1991 federal special education laws improved the availability of educational services for children with autism.

The study used data from the Rochester Epidemiology Project, a database of all inpatient and outpatient records in Olmsted County, Minn. The database diagnoses are indexed for computerized retrieval, allowing researchers to identify subjects with any developmental disorder. Researchers found 3,000 children with at least one of 80 diagnoses related to autism. Of the 3,000 children, 124 actually met the current diagnostic criteria for autism. Reviewing the medical and school history of this group showed that the incidence of autism was stable until 1988-1991, then increased after new laws and new diagnostic criteria were implemented.

Other authors of the report in the January issue of Archives of Pediatrics and Adolescent Medicine are: Slavica Katusic, M.D., Robert Colligan, Ph.D., Amy Weaver, M.S., and Steven Jacobsen, M.D., Ph.D. The full article is available by contacting Archives of Pediatrics and Adolescent Medicine at 312-464-5262. It is also available at http://pubs.ama-assn.org/media/.

Media Contact

Lee Aase EurekAlert!

All latest news from the category: Health and Medicine

This subject area encompasses research and studies in the field of human medicine.

Among the wide-ranging list of topics covered here are anesthesiology, anatomy, surgery, human genetics, hygiene and environmental medicine, internal medicine, neurology, pharmacology, physiology, urology and dental medicine.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors