The Minnesota Department of Health has confirmed what Minneapolis school officials have long suspected: that there's a "significantly higher" proportion of Somalis than others in the city's preschool programs for autism.
But it still doesn't know why.
In a report released Tuesday, the Health Department said that the findings raise more questions than answers and that they are "not proof that Somali children have more autism than other children."
The investigators said they were not able to determine whether the numbers are merely a statistical blip or reflect a deeper problem.
"We recognize this study is only the first step on a very long journey," said Dr. Sanne Magnan, the commissioner of health, in a letter accompanying the report. She said the study showed that the concerns raised by parents "were important and legitimate," and that much more research will be needed to find the answers.
The Health Department launched its investigation last fall, after Minneapolis school officials and parents raised concerns about the disproportionate number of Somali children in the city's early-childhood autism program. Those reports made headlines around the country, in part because such a cluster could help scientists shed light on the causes of autism.
In this case, health investigators said they could not compare autism rates among Somali and non-Somali children, because no precise medical data exist. So they focused instead on the school data used to identify children for special education.
The investigation found that, among 3- and 4-year-olds in Minneapolis, Somali children were two to seven times likelier than others to be in special classes for autism, a brain disorder linked to behavior problems.