January 8, 2008
California Autism Cases Continue to Grow
Thimerosal, a Mercury-based preservative once used in routine childhood vaccines, may not be a cause of autism as previously believed. After the preservative's removal from shots in 2001, cases of Autism in California are still climbing. Over 5,000 claims have been lodged with the federal government blaming thimerosal for the impaired social interaction characteristic of autism; however this line of blame is being proven implausible.
During a 12 year study the California Department of Public Health has seen the autism rate in children rise continuously. If there were a risk due to this particular preservative, the rate of autism would have dropped significantly between 2004 and 2006. Dr. Eric Fombonne, an autism researcher at Montreal Children's Hospital who was not involved in the study said that there was "no evidence of mercury poisoning in autism".
State public health officials calculated the autism rate by analyzing a database of state funded centers that care for autism and other neurological disorders. During the study period, autism in children ages 3 to 12 dramatically increased. By age 3, .3 out of every 1000 babies born in 1993 had autism. This number is surprisingly small compared to a latter statistic; out of the babies born 10 years later, in 2003, by age 3, 1.3 out of every 1000 had autism. These upward trends can be seen in other age groups as well. These numbers are inconsistent with the hypothesis that thimerosal exposure is a primary cause of autism in California.
The chief science officer for an autism advocacy group, Autism Speaks, thinks that all possible causes for autism should be explored aggressively, and agrees that the study done by the California Department of Public health was a very important one. "The bulk of the evidence thus far suggests that mercury is not involved, but I think parents still have many questions," Dawson claims. "I think until parents are satisfied, we need to continue to examine the question."
Many other Doctors, including Dr. Daniel Geschwind, a neurologist at the David Geffen School of Medicine at the University of California in Los Angeles, think that genetic links should be the focus of future studies. He states, "Something else must be at play and we need to know what that is if we're really serious about preventing autism."