Hispanic kids are less likely than their non-Hispanic white counterparts to be diagnosed with autism, and socioeconomic factors don't seem to explain the difference, according to a new study in Texas schoolchildren.
"These findings raise questions: Is autism under diagnosed among Hispanics? Are there protective factors associated with Hispanic ethnicity?" Dr. Raymond F. Palmer of the University of Texas Health Science Center in San Antonio and his colleagues write in the American Journal of Public Health.
Other research has shown a lower risk of autism among Hispanic individuals, while one study found that Hispanics with autism were typically diagnosed later than autistic children of other ethnic backgrounds. Autism could be under diagnosed among Hispanics, Palmer and his team note, given that these children are less likely to have health insurance and more likely to have trouble accessing medical care.
To investigate the factors behind the difference in prevalence, the researchers looked at data on 1,184 schools in 254 Texas counties, calculating the number of children in kindergarten through 12th grade in each district who had been diagnosed with autism.
For every 10 percent increase in Hispanic schoolchildren in a given district, the researchers found, the prevalence of autism decreased by 11 percent, while the prevalence of kids with intellectual disabilities or learning disabilities increased by 8 percent and 2 percent, respectively.
The reverse was seen as the percentage of non-Hispanic white children in a district increased, with the prevalence of autism rising by 9 percent and the prevalence of intellectual and learning disabilities falling by 11 percent and 2 percent.
The observed relationships remained for Hispanic children after the researchers accounted for key socioeconomic and health care provider factors, although "urbanicity" of a district, median household income, and number of health care professionals did explain the increased percentage of autism among districts with more non-Hispanic white kids -- a finding the researchers call "curious."
Whether lower autism prevalence in Hispanics is attributable to other, still-unexamined socioeconomic, health care delivery or biological factors "remains a crucial area for further research," Palmer and colleagues conclude.
SOURCE: American Journal of Public Health, December 2009.
