Recent trends suggest that autism rates are rising across the U.S. That is alarming, in and of itself. But new statistics show that the disorder appears to be more prevalent in certain communities. A few studies out of California may shed some light on these baffling questions.

A recent study conducted at Columbia University identified an area including West Hollywood and Beverly Hills that accounts for 3 percent of the state's new cases of autism from 1993 to 2001, even though it accounts for only 1 percent of the population. A similar study, this one out of the University of California-Davis, also found high rates of autism in children born around Los Angeles, as well as nine other California locations.  

Both of these California-based studies suggest that the location itself — whether it's because of environmental or sociological factors — is the cause of the high autism-diagnosis rates. California isn't the only state to see these unusual spikes. Metropolitan Phoenix, for example, has twice the prevalence of autism as northern Alabama. These latest findings support the notion that childhood vaccinations are not to blame for the condition. If they were, advocates say, these autism diagnoses would be more evenly dispersed around the state.

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