Which of the following is a function of epidemiology?

• A. To describe clinical case reports in isolation
• B. To discover agent, host, and environmental factors that affect health to prevent disease
• C. To determine the best surgical techniques
• D. To develop personal treatment plans for individuals

Answer: (D)

Epidemiology focuses on how diseases affect populations by identifying the factors related to agents, hosts, and the environment, and using that knowledge to prevent disease and protect public health. The statement about discovering agent, host, and environmental factors to prevent disease captures this population-level, preventive aim. The other ideas are rooted in individual patient care—describing clinical cases in isolation, focusing on surgical techniques, or creating personal treatment plans—which are clinical or case-based rather than epidemiology-driven. So the function of epidemiology is best described as identifying determinants that inform disease prevention at the population level.