Studies in medicine are designed to identify cause of disease. The ultimate goal of such studies is to alter the frequency or severity of these diseases. All of the following are considerations in the determination of causality EXCEPT: (AIIMS Nov 10)
|A||Temporal sequence – causative agents must precede their consequences|
|B||Biological gradient – dose response curve|
|C||Concurrency – cause and effect are found at the same time|
|D||Strength of association|
Determination of the presence of a cause and its effect at the same time, such as on a cross-sectional survey, does not support causality. The cause must be shown to precede the effect in time. In some cases, the cause may be present for years in the past, such as with radiation exposure and thyroid cancer. In this case, these events would not be apparent at the same time, yet the relationship would be causal.