Is Autism More Likely to Occur With Highly Educated Parents?
A study published this week by the University of California at Davis reveals the discovery of clusters of autism in places where the parents are older, Caucasian, and have higher than average levels of education.
Researchers at UC Davis MIND Institute found ten clusters in California among children born between 1996 and 2000, primarily in San Diego, Los Angeles, San Francisco and the Central Valley. A cluster is defined as any geographic distribution in which there is markedly higher incidence of the diagnosis.
The findings, published online in Autism Research, raise the question of a correlation between advanced education levels and likelihood of seeking a diagnosis. "There is mounting evidence that at least some of this clustering results from the greater access and utilization of services by those with more years of schooling." It is not known if there are other correlating factors, including exposure to household chemicals in homes where education and income is higher. Children within the clusters were found to be more than twice as likely to have a diagnosis of autism than children in surrounding areas.
The study did not find any environmental factors which would account for the higher incidence of diagnosis.
According to Karla C. Van Meter, lead author of the study, "In the U.S., the children of older, white and highly educated parents are more likely to receive a diagnosis of autism or autism spectrum disorder. For this reason, the clusters we found are probably not a result of a common environmental exposure. Instead, the differences in education, age and ethnicity of parents comparing births in the cluster were striking enough to explain the clusters."
From the article, the clusters occur in the following areas:
1. The Westside Regional Center, headquartered in Culver City, Calif., which serves the communities of western Los Angeles County, including the cities of Culver City, Inglewood and Santa Monica;
2. The Harbor Regional Center, headquartered in Torrance, Calif., which serves southern Los Angeles County, including the cities of Bellflower, Harbor, Long Beach and Torrance;
3. The North Los Angeles County Regional Center, headquartered in Van Nuys, Calif., which serves the San Fernando and Antelope valleys — two clusters were located in this regional center’s service zone.
4. The South Central Los Angeles Regional Center, headquartered in Los Angeles, which serves the communities of Compton and Gardena;
5. The Regional Center of Orange County, headquartered in Santa Ana, Calif., which serves the residents of Orange County; and
6. The Regional Center of San Diego County, headquartered in San Diego, which serves people living in Imperial and San Diego counties.
7. The Golden Gate Regional Center, headquartered in San Francisco, which serves Marin and San Mateo counties and the City and County of San Francisco. Two clusters were located within the Golden Gate Regional Center’s service zone; and
8. The San Andreas Regional Center, headquartered in Campbell, Calif., which serves Santa Clara, Santa Cruz, Monterey and San Benito counties.
9. The Central Valley Regional Center, headquartered in Fresno, Calif., which serves Fresno, Kings, Madera, Mariposa, Merced and Tulare counties; and
10. The Valley Mountain Regional Center, headquartered in Stockton, Calif., which serves Amador, Calaveras, San Joaquin, Stanislaus and Tuolumne counties.
The research comes on the heels of recent findings indicating that one in a hundred eight-year-olds now has the diagnosis. The CDC in December called the rise of the disorder "an urgent public health concern." The CDC found the incidence of autism diagnosis to be significantly higher in boys than girls, 1 in 70 compared to 1 in 315.
On the Web:
UC Davis Researchers Identify Autism Clusters in California - UC Davis MIND Institute
Prevalence of Autism Spectrum Disorders - CDC (December 18, 2009 Morbidity and Mortality Report)