Which theory is described as making causal inference harder for chronic diseases due to multiple exposures over time?

• A. Miasma Theory
• B. Germ Theory
• C. Theory of Multiple Causality
• D. Koch Postulates

Answer: (C)

Chronic diseases often arise from a network of factors that accumulate and interact over time. The Theory of Multiple Causality holds that diseases result from several component causes acting together, with different combinations producing disease in different people. Because exposures accumulate, interact, and vary across individuals and time, pinpointing a single cause becomes much harder, which is exactly what this theory describes.

In contrast, Miasma theory attributes disease to bad air, Germ Theory pins disease to a specific pathogen, and Koch Postulates focus on proving a particular microbe causes a disease—perspectives that don’t account for the complex, time-dependent, multifactorial inputs typical of chronic illnesses.