A new method for deriving incidence rates from prevalence data and its   application to dementia in Germany
  This paper descibes a new method for deriving incidence rates of a chronic disease from prevalence data. It is based on a new ordinary differential equation, which relates the change in the age-specific prevalence to the agespecific incidence and mortality rates. The method allows the extraction of longtudinal information from cross-sectional studies. Applicability of the method is tested in the prevalence of dementia in Germany. The derived age-specific incidence is in good agreement with published values. 
Ralph Brinks
q-bio.QM q-bio.PE stat.ME