Calculation of the mean duration and age of onset of a chronic disease   and application to dementia in Germany
  This paper descibes a new method of calculating the mean duration and mean age of onset of a chronic disease from incidence and mortality rates. It is based on an ordinary differential equation resulting from a simple compartment model. Applicability of the method is demonstrated in data about dementia in Germany. 
Ralph Brinks
q-bio.QM q-bio.PE stat.AP stat.ME