By Margarita Nahapetyan
According to a new study, published in the current issue of the journal Epidemiology, environmental factors and not genetics might be the cause of autism. The M.I.N.D. Institute, a leading autism research facility is presently conducting a study to look at the possible effects of metals, pesticides, household chemical products and infectious agents on neurodevelopment. "It's time to start looking for the environmental culprits responsible for the remarkable increase in the rate of autism in California," Irva Hertz-Picciotto, Ph.D., M.P.H., chief of the division of environmental and occupational health at the University of California, Davis, said in a news release.
Autism is the most common condition in a group of developmental disorders known as Autism Spectrum Disorders (ASD). There are several main factors in behavior that characterize the disorder: people with autism have trouble with verbal and nonverbal communication, they have problems with social interaction, they often play with toys in unusual ways and have repetitive patterns of behavior, and sometimes very limited activities and interests. The symptoms usually are evident by the time the child is a toddler and parents are usually the first to notice symptoms of autism in their child. As early as infancy, a baby with autism avoids straight eye contact, he(she) may be unresponsive to people, or focus intently on one item.
The number of autism cases in the United States has increased dramatically in the past fifteen years, but no state has seen as large an increase as California. According to statistics, more than 3.000 new cases of autism were reported in California in 2006 while only 205 cases were reported in 1990. In 1990, 6.2 in 10,000 children born in the state were diagnosed with autism by the age of five. In 2001 already 42.5 in 10.000 were diagnosed autistic by the age of five. The numbers have been continuously rising since then.
Many scientists have believed that the dramatic and continuous increase in cases of autism over the last 15 years, particularly the huge increase seen in California, isn't natural. For years, most of them have suspected that the trend is artificial-due to changes in diagnoses or migration to the state of the families with autistic children, patterns rather than a real rise in the disease. Hertz-Picciotto and her co-author, Lora Delwiche of the UC Davis Department of Public Health Sciences, analyzed 16 years of records (from 1990 till 2006) and excluded children that were not born in California, they also eliminated migration as a possible cause for the increase. The census data was used to calculate the rate of autism over time and the age of a child at diagnosis. The data was collected by the state of California Department of Developmental Services (DDS) as well as the United States Census Bureau and state of California Department of Public Health Office of Vital Records, which compiles and maintains birth statistics.
There is also another opinion and belief that childhood vaccination might be the cause of autism in children. The vaccines contain thimerosal, a mercury compound used as preservative. But there is a controversy as thimerosal had been removed from the vaccines since 1999 but the autism rates are still climbing up with a drastic speed.
Says Hertz-Picciotto, "We're looking at the possible effects of metals, pesticides and infectious agents on neurodevelopment. If we're going to stop the rise of autism in California, we need to keep these studies going and expand them to the extent possible." "Right now, about 10 to 20 times more research dollars are spent on studies of the genetic causes of autism than on environmental ones. We need to even out the funding." The other very important question that public-health officials really need to take into consideration according to Hertz-Picciotto is that they should prepare to offer services to the increasing number of autistic children who are now entering their late teen years. "These children are now moving toward adulthood, and a sizeable percentage of them have not developed the life skills that would allow them to adapt to live independently," she said. "What happens to them when their parents cannot take care of them?"
Dr. Bernard Weiss, a professor of environmental medicine and pediatrics at the University of Rochester Medical Center who was not involved in the new study, said the rate of autism cases reported in the research "seems astonishing." He also strongly suggested that environmental factors should be getting more attention. "The advances in molecular genetics have tended to obscure the principle that genes are always acting in and on a particular environment," he said. "This article, I think, will restore some balance to our thinking."
So could the environment play a bigger role than was previously thought and be considered as a reason causing autism? Are vaccinations still to be blamed? There is still no answer to these questions. There is no cure for this mysterious disease, but the study shows that diagnosis at an early stage and treatment can greatly improve a child's development. At present, there are no tests that exist to diagnose this disorder, but the latest research suggests better ways to diagnose autism may be on the horizon.
The Hertz-Picciotto research was funded by grants from the National Institute of Environmental Health Sciences (NIEHS) and by the M.I.N.D. Institute.