Autism rates have changed significantly since my son was diagnosed 10 years ago. At that time it was common to read estimates ranging from 1 in 500 to 1 in 1000. But the estimates started changing to 1 in 250, then 1 in 166 and now 1 in 150. In the UK the figure currently used is 1 in 100. There are many today who believe that changes in the definition of autism introduced in the DSM-IV combined with diagnostic substitution explain the dramatic increases in autism disorder diagnoses. But the advocates of this theory really have no solid studies providing precise measurements to substantiate the belief that the autism increases are all largely changes in how we view autism rather than actual increases in incidents of autism.
The definition change believers seem to be on solid ground to the extent that they argue that such change is a substantial contributing factor to the increases in autism diagnoses. They seem to stretch their belief beyond reason though when they assert dogmatically that the increases are due entirely to these social factors and rule out any environmental increases. The well known identical twins studies show that, in some cases, one identical twin will receive an autism diagnosis but the other will not, suggesting a role for environmental factors in autism causation.
In Neurodevelopmental Disorders in ChildrenAutism and ADHD Mona Sethi Gupta, Ph.D. examines environmental factors that may disrupt neurological development including lead, mercury, PCBs, dioxins, arsenic and toluene. Dr. Gupta discusses some studies suggesting environmental contributors to increasing neurodevelopment problems among children who are more sensitive to environmental toxins than adults and reminds us of the thalidomide tragedy. Dr. Gupta notes emphasizes the importance of taking action to protect children from environmental toxins:
"The impact of environmental toxins on children’s health has become a major focus in the federal government resulting in establishment of eight new research centers in children’s environmental health with joint funding from EPA and the National Institute of Environmental Health Sciences (NIEHS). "The brains of our children are our most precious economic resource, and we haven't recognized how vulnerable they are," says Philippe Grandjean, adjunct professor at Harvard School of Public Health and the lead author of the study published in The Lancet . "We must make protection of the young brain a paramount goal of public health protection. You have only one chance to develop a brain.""
There are those who argue dogmatically that environmental factors are not involved in causing autism and that the startling autism increases are due entirely to definition change and diagnostic substitution. They may honestly believe their assertions or they may be tied to promotion of book royalties or blog site advertising but modern history, thalidomide, tobacco and cancer, suggest greater caution in ruling out all environmental contributors to autism and other developmental disorders. Our children deserve better than for society to rely on the faith and belief of dogmatists on such important issues.
1. An arrogantly assertive person.
2. One who expresses or sets forth dogma.
|dogmatist - a stubborn person of arbitrary or arrogant opinions