<prompt> Which of the following will cause an increase in the prevalence of disease?Immigration of healthy personsIncreased cure rate of diseaseLonger duration of diseaseIncreased death rate in disease  <response>: Prevalence depends upon 2 factors, the incidence I and duration of illness D. Given the assumption that the population is stable, and incidence and duration are unchanging, the relationship between incidence and prevalence is, P I D Incidence mean duration Therefore when duration increases prevalence also increases. Ref: Parks Textbook of Preventive and Social Medicine, By K. Park, 19th Edition, Page 57; How to Repo Statistics in Medicine By Thomas Allen Lang, 2nd Edition, Pages 165-6 