The recent rise in the rates of autism has often been explained as a result of better diagnosis and an increased awareness of the condition. However, a review of data from the California Department of Development Services has found that there could be an increase in the actual incidence of the condition. The cumulative incidence of autism per 10,000 births climbed from 6.2 in 1990 to 42.5 in 2001. A change in the age at diagnosis could explain 12% of the increase, while the inclusion of milder cases could explain 56% but the researchers - from the University of California, Davis - concluded that "the possibility of a true increase in incidence deserves serious consideration."
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