The fact that the confidence interval range includes 1 means that the finding was not statistically significant.
The population for those two specific diagnoses were low in the study. Diagnostic patterns change over time for these type of disorders. Considering neurodevelopmental outcomes as a group may add more color.
You are correct that the study failed to disprove a link between aluminum and aspergers. But the study did prove a that if there is a link it does not result in a moderate to large increase in aspergers risk.
The population for those two specific diagnoses were low in the study. Diagnostic patterns change over time for these type of disorders. Considering neurodevelopmental outcomes as a group may add more color.
You are correct that the study failed to disprove a link between aluminum and aspergers. But the study did prove a that if there is a link it does not result in a moderate to large increase in aspergers risk.