Over 12 months, the prevalence of a non-infectious disease will increase in a population if: A - HSC - SSCE Biology - Question 17 - 2020 - Paper 1

To understand why the prevalence of a non-infectious disease increases when the survival time of individuals with the disease increases, we must look at the definitions and relationships in epidemiology.

Prevalence is defined as the total number of cases of a disease in a population at a given time. If individuals with a non-infectious disease are living longer due to increased survival time, they remain part of the overall population, thereby increasing the number of cases.

In contrast, other options either do not directly affect prevalence or suggest a decrease in cases:

• Option A may increase prevalence due to a larger population, but it is not a guaranteed effect without considering disease dynamics.
• Option B suggesting reduced recovery time implies that individuals would be returning to a healthy state more quickly, which would likely decrease prevalence.
• Option C indicates a decrease in incidence, leading to fewer new cases and ultimately lowering prevalence.

Thus, the correct answer is option D, as an increase in survival time directly correlates with an increase in the number of individuals living with the disease, thereby raising overall prevalence.