I need information on the disease frequency distribution among age groups for an Android app I'm building... Hopefully I've come to the right place. Is there a good data source for this? Like a bioinformatics database?
You may need to study each disease individually or do a literature review. The Online Mendelian Inheritance in Man website may be a good starting point http://www.omim.org/ The Centers for Disease Control and Prevention lists several diseases with a variety of different statistics here: http://www.cdc.gov/DiseasesConditions/