Which of the following best describes the scope of epidemiology's focus?

• A. All health problems in populations
• B. Only infectious diseases
• C. Only chronic diseases
• D. Only hospital-acquired infections

Answer: (A)

Epidemiology looks at how health problems are distributed in populations and what determines those patterns, and it applies this across all health outcomes, not just one type. This broad view includes infectious diseases, chronic diseases, injuries, and health issues in various settings, from communities to hospitals, so the methods and questions fit the full spectrum of population health.

That breadth is why the description of epidemiology as focusing on all health problems in populations fits best. The other options are too narrow, naming only infectious diseases, only chronic diseases, or only hospital-acquired infections, which misses the wide range of health issues epidemiology covers.