Entry By: Dr. Esther Hess
I just reviewed the following article by Sallie Bernard which gives her thoughts on a recent conference on autism. The debate over genetic and/or environmental causes of autism rages on….Esther Hess, Ph.D.
Click here to read the article: “Feeling exposed? Insights from a new meeting on environmental impacts in autism“ by Sallie Bernard, Autism Speaks’ Board Member, co-founder and Executive Director of Safe Minds
Given the historic inattention of the scientific establishment to the environmental contributions to autism, it was nice to see a day-long conference on the topic held this week by a major research center. “Exploring the Environmental Causes of Autism and Learning Disabilities” was put together by the Children’s Center for Environmental Health at the Mount Sinai School of Medicine in New York City. The center is run by Dr. Phil Landrigan, who has been a prominent researcher on the harmful effects of environmental toxicants for decades. He told the incredible story of the harms of lead exposure on children’s cognition and behavior, and how the successful effort to remove leaded gasoline from the market in the 1970s resulted in rising IQ scores and economic gain to the country. I hope this same massive effort will be applied to autism and the chemicals which underlie the increase in its prevalence.
Also of note was the presence at the meeting of Linda Birnbaum. Dr. Birnbaum is the director of the National Institute of Environmental Health Sciences (NIEHS) which holds the autism/environment portfolio at NIH. The Mt. Sinai meeting follows on a workshop held at NIEHS several months ago which explored the role of the environment in autism. Large scientific initiatives in the field fall to the NIH, so without its support, gains will be painfully slow. Hopefully Dr. Birnbaum’s personal involvement signals a heightened interest at NIEHS to look at autism. Although Dr. Birnbaum stated at the conference that her institute spends $30 million on children’s environmental health, at a Senate hearing earlier this year, it was shown that just $8 million of this is for autism specifically.
A few interesting bits of information came out of the conference. One was the definition of “environment” that the insiders use. It covers synthetic chemicals like pesticides, flame retardants and plasticizers; heavy metals like arsenic, lead and mercury; combustion and industrial by-products; diet and nutrients; medications, medical interventions, and substance abuse; infections; the microbiome; heat and radiation; and lifestyle factors. Some may be harmful; others protective. They may operate before conception, during pregnancy or in early life, and some may alter gene expression through epigenetic modifications to chemicals surrounding our genes. Craig Newshaffer, who runs the EARLI study to look at environmental factors among younger autism siblings, referred to the concept of the “exposome”, that is, everything we are exposed to and its effects on health. Dr. Birnbaum’ made the point that health does not equal medicine, and prevention through reduction in chemical exposures is of equal importance to health. Colleen Boyle from the CDC stated that the next prevalence report will be issued in April 2011. We will see if the 1 in 110 number from last year’s report has changed. New research from Korea was unable to confirm increased risk of autism due to parental age or low birth weight, which have been identified as risk factors in Western studies.
The most informative talk was by Dr. Irva Hertz-Picciotto from UC-Davis. She explained how changes in diagnosis do not account for most of the increase in autism rates, and how recent research by their group on mercury and flame retardant blood levels do not address whether these substances are causative for autism because the blood samples were taken years after the autism diagnosis. A paper out this week from UC-Davis found that proximity to traffic air pollution during pregnancy almost doubles the risk of autism. Another paper just accepted by a journal has found higher antibodies to cerebellar tissue in children with autism relative to controls, highlighting the immune component in autism.
Other than these interesting items, the conference covered minimal new ground as far as the science goes. Rather, the points of the meeting seemed to be to make the case that environmental factors research in autism must now be considered mainstream science and to showcase the work being done or about to be done to investigate the issue. Dr. Landrigan made the case for an environmental role by noting that the rate of autism has increased too much to be solely genetic, and that at most, genetics alone will end up explaining 40% of autism cases with the likely percentage much lower.