A Positive Association
found between Autism Prevalence and Childhood Vaccination uptake across the U.S.
Population.
Delong G.
J Toxicol Environ Health A. 2011 Jan;74(14):903-16.
pdf here
The reason for the rapid rise of autism in the United States that began in the
1990s is a mystery. Although individuals probably have a genetic predisposition
to develop autism, researchers suspect that one or more environmental triggers
are also needed. One of those triggers might be the battery of vaccinations that
young children receive. Using regression analysis and controlling for family
income and ethnicity, the relationship between the proportion of children who
received the recommended vaccines by age 2 years and the prevalence of autism (AUT)
or speech or language impairment (SLI) in each U.S. state from 2001 and 2007 was
determined. A positive and statistically significant relationship was found: The
higher the proportion of children receiving recommended vaccinations, the higher
was the prevalence of AUT or SLI. A 1% increase in vaccination was associated
with an additional 680 children having AUT or SLI. Neither parental behavior nor
access to care affected the results, since vaccination proportions were not
significantly related (statistically) to any other disability or to the number
of pediatricians in a U.S. state. The results suggest that although mercury has
been removed from many vaccines, other culprits may link vaccines to autism.
Further study into the relationship between vaccines and autism is warranted.