The CDC found a 236% increased risk of autism in African-American boys associated with the MMR vaccine
Table 3 shows results for the entire cohort excluding African American children. As can be observed, there is no statistically significant effect for any of the subclasses in either gender or age cut-off for MMR uptake. This shows that the effect observed overall is due to the very strong "signal" seen exclusively in African American boys. In other words, the strong, statistically significant relationship between younger first MMR age and higher autism incidence in African American males may be skewing the results for larger, more general populations that include African American males (e.g., all boys and all African Americans) to show a "relationship" that is actually only in African American males.