I have the overall age-specific incidence of a disease in a country, as well as disease cases and crude incidence in regions. According to these, how can I estimate the age-specific incidence in the regions?
If I understand you correctly you can simply sort your data output by a specific variable, in this case your variable that displaces incidences in regions. Depending on which program you use you will have to adjust your settings accordingly.
After that the statistical analysis of your incidences by age will be automatically sorted by regions.