It is arrived at by comparing the number of people found to have the condition with the total number of people studied, and is usually expressed as a fraction, as a percentage, or as the number of cases per 10,000 or ratio and proportion pdf pearson,000 people. Prevalence estimates are used by epidemiologists, health care providers, government agencies, toxicologists, and insurers. The difference between prevalence and incidence can be summarized thus: prevalence answers “How many people have this disease right now?
How many people have had this disease during this time period? How many people per year newly acquire this disease? For example, the prevalence of obesity among American adults in 2001 was estimated by the U. It could describe how many people in a population had a cold over the cold season in 2006, for example. Point prevalence is akin to a flashlit photograph: what is happening at this instant frozen in time. It is like a snap shot of the disease in time.