ESC5114 Epidemiology

1. Cumulative incidence is best described as:

• The number of new cases of a disease in a population during a specific time period divided by the average population at risk.

• The total number of cases of a disease in a population at a specific point in time.

• The proportion of a population that develops a condition over a specified time period.

• The proportion of a population that develops a condition over a specified time period.

Which of the following is true about incidence rate?

• It is also known as the risk of disease.

• It accounts for the time each individual is at risk in the study.

• It is synonymous with cumulative incidence.

• It includes both new and existing cases of a disease.

What is the key difference between incidence rate and cumulative incidence?

• Incidence rate measures prevalence, while cumulative incidence measures incidence.

• Incidence rate accounts for time, while cumulative incidence does not.

• Incidence rate includes both new and old cases, while cumulative incidence includes only new cases.

• Cumulative incidence is expressed as a rate, while incidence rate is expressed as a proportion.

Point prevalence measures:

• The number of new cases of a disease over a defined time period.

• The proportion of a population affected by a disease at a single point in time.

• The number of cases per unit time per person at risk.

• The lifetime risk of a disease.

Period prevalence refers to:

• The number of new cases over a specific time frame.

• The proportion of individuals with a disease at any time during a specified period.

• The incidence rate adjusted for seasonal variation.

• The population at risk during a specific time period.

If 10 out of 100 people develop a disease in one year, the cumulative incidence is:

• 0.1 per year.

• 10%.

• 100 per 1,000 person-years.

• Both 0.1 per year and 10%

A population has 1,000 individuals at the beginning of a study. Over two years, 100 develop a disease. What is the cumulative incidence?

• 10 per 1,000 person-years.

• 5%.

• 10%.

• Cannot be calculated from this data.

Which statement best describes the relationship between point prevalence and incidence?

• Point prevalence equals incidence divided by the population at risk.

• Point prevalence includes all cases, while incidence only includes new cases.

• Point prevalence cannot be measured if incidence is known.

• Incidence measures risk, while point prevalence measures the duration of disease.

A study finds that 20 individuals in a population of 500 have diabetes at a single time point. What is the point prevalence?

• 4%.

• 20%.

• 5 cases per 1,000 person-years.

• 10%.

Period prevalence differs from cumulative incidence because:

• Period prevalence includes only new cases during the period.

• Period prevalence includes all cases (new and existing) during the period.

• Cumulative incidence includes existing cases at the start of the period.

• Period prevalence accounts for the duration of disease.