Which causation criterion requires that exposure precedes disease?

• A. Temporality
• B. Dose-response
• C. Strength
• D. Consistency

Answer: (A)

Exposure must occur before the disease in time. This time-order sequence is essential for inferring causation because only if the exposure comes first can we argue it contributed to the development of the disease, not the other way around. If the disease occurs before or at the same time as the exposure, the exposure cannot be the cause. This requirement is what links an exposure to the subsequent disease. Dose-response looks at whether higher exposure leads to higher risk, strength describes the magnitude of the association, and consistency concerns replication across studies. These aspects are important for building causal confidence, but they don’t establish that the exposure happened before the disease, which is the key element here.