Which statements represent the two fundamental assumptions of epidemiology?

• A. Disease occurs randomly and determinants cannot be identified
• B. Disease does not occur at random and determinants can be identified
• C. Disease is solely genetic
• D. Disease occurs randomly but determinants are identifiable

Answer: (B)

In epidemiology, disease does not occur at random and there are identifiable factors that influence who gets sick. This means that the patterns we see—who is affected and how often—are shaped by exposures and conditions in the population, such as behavior, environment, genetics, and social factors, not by pure chance alone. Importantly, we can identify and measure these determinants through studies, which lets us understand risk factors, predict where disease may spread, and design prevention and control measures. For example, smoking is a determinant for lung cancer, and its presence helps explain why some groups have higher rates than others.

Other statements imply either that disease happens by chance without any identifiable factors, or that disease is purely genetic, or that randomness and identifiable factors can coexist in a way the fundamental view of epidemiology does not support. The best statement captures both ideas: disease does not occur at random and determinants can be identified.