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Question 685
Statistics → Epidemiology
Classification
Question
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Statistics
Question Stem
Which statement best defines the prevalence of a disease?
Options
A
The number of newly diagnosed cases during a specified period
B
The proportion of the population with the disease at a specified point in time
C
The proportion of unaffected individuals who subsequently develop the disease
D
The number of deaths attributable to the disease during a specified period
E
The proportion of positive screening tests that are true positives
Explanation
Prevalence describes the proportion of people in the entire population who have a disease at a specified point in time or within a defined interval. It measures existing or current cases rather than newly diagnosed cases. that prevalence can be estimated from a cross-sectional study and can help determine the health needs of a community. It is influenced by both the incidence and the duration of the disease.
Option Validity
A) Newly diagnosed cases over a specified period describe incidence.
C) This describes subsequent occurrence of disease rather than existing disease burden.
D) Disease-specific mortality is not prevalence.
E) This describes positive predictive value.
Further Reading
Saxena - MRCOG-1 Basic Sciences, Chapter 10: Epidemiology/Statistics, Printed p.287.