On March 1, 2022, a survey was conducted with 330 Chicago public school students. Forty of them reported ever being diagnosed as having asthma. This measure is an example of:
A. Lifetime prevalence
B. Cause-specific mortality
C. An adjusted prevalence rate
D. Point prevalence
The correct answer and explanation is:
The correct answer is A. Lifetime prevalence.
Lifetime prevalence refers to the proportion of individuals in a population who have ever been diagnosed with a specific condition or disease at any point in their lifetime up until the time of the survey. In this case, the survey asked about students who have ever been diagnosed with asthma, meaning it tracks whether the condition has occurred at any point in the participants’ lives, not just at a specific moment in time.
In the context of this survey, 40 out of 330 students reported being diagnosed with asthma, indicating that these individuals had received an asthma diagnosis at some point in their lives. Since the survey does not focus on current or past diagnoses at a particular time (like a recent survey), but rather on the lifetime occurrence of the condition, this data is best categorized as lifetime prevalence.
Here’s how the other options differ:
- Cause-specific mortality refers to the number of deaths in a population due to a specific cause, such as asthma-related deaths, which is not relevant in this scenario.
- An adjusted prevalence rate is a measure of prevalence that accounts for variables such as age or gender to allow comparisons across different populations. This measure is not being used here, as no adjustments for demographics are mentioned.
- Point prevalence refers to the proportion of individuals who have a specific condition at a single point in time (e.g., on the date the survey was conducted), which is different from asking about whether someone has ever been diagnosed with the condition.
Therefore, since the survey is asking about students who have ever been diagnosed with asthma in their lifetime, it falls under the category of lifetime prevalence.