Anesu Gavhera

Incidence vs Prevalence

In epidemiology, incidence and prevalence are two fundamental measures that describe the occurrence of diseases or health conditions in a population. They provide distinct perspectives on the burden of a disease and are used to answer different questions:

1. Incidence: Incidence refers to the rate at which new cases of a specific disease or health condition develop within a population during a defined period of time. It focuses on the occurrence of new or "incident" cases. Incidence measures are typically expressed as a rate or a proportion.
2. Incidence is often used to study the risk of developing a disease and can help identify factors associated with the onset of the condition. It is useful for assessing disease trends, planning interventions, and understanding the causes of diseases.

• Incidence rate = (Number of new cases during a specific time period) / (Population at risk during the same time period) × 1,000 or 100,000 (to express as cases per 1,000 or 100,000 people)

1. Prevalence: Prevalence, on the other hand, refers to the total number of cases (both new and existing) of a disease or health condition present in a population at a specific point in time or over a defined period. Prevalence provides a snapshot of the overall burden of the disease within a population.
2. Prevalence is often used to describe the overall impact of a disease on a population and to estimate the total number of people affected. It is valuable for healthcare planning, resource allocation, and understanding the long-term effects of a disease.

• Prevalence = (Number of cases at a specific time) / (Total population at that specific time) × 100 or 1,000 (to express as a percentage or per 1,000 people)

"In epidemiology, prevalence tells us how widespread a health condition is in a population at a specific point in time, while incidence measures how many new cases of the condition occur during a defined time period."

Video Example

The following video explains the difference between Incidence and Prevalence:

Selected Article on Prevalence vs Incidence

The following link directs you to a research paper conducted by Majid Mobasseri. In this paper titled "Prevalence and incidence of type 1 diabetes in the world: a systematic review and meta-analysis", Mobasseri conducts a comprehensive review and meta-analysis of existing research to determine the prevalence and incidence rates of type 1 diabetes worldwide.

Link to the Paper

The study found that the global prevalence of T1D was 9.5% (95% CI: 0.07 to 0.12) in 2019. The prevalence was highest in Northern Europe (12.5%) and lowest in Africa (4.1%). The global incidence of T1D was 15 per 100,000 people (95% CI: 13 to 17) in 2019. The incidence was highest in Finland (33 per 100,000 people) and lowest in Australia (10 per 100,000 people).

The study also found that the prevalence and incidence of T1D are increasing worldwide. The authors suggest that this is due to a combination of genetic and environmental factors.