Which of the following will cause an increase in the prevalence of disease?
Immigration of healthy persons
Increased cure rate of disease
Longer duration of disease
Increased death rate in disease
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: Park's 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