Question

The following quotation comes from a review of research on diet in relation to levels of serum lipids: Many studies were limited by having a small number of participants. Diet studies quoted to this day as authoritative had as few as five subjects. If any enduring truth has emerged about human beings and diet, it is that everyone is remarkably different, and studies that don’t involve dozens if not hundreds of participants are of extremely limited value.

1. How is it possible for an epidemiologic study (of any question) that involves fewer than dozens or hundreds of participants to be more than limited valued?

Answer 1

Of course, when associations are not so strong, perhaps in the case of diet in relation to serum lipids _studies of dozens if not hundreds (if not more) participants are needed to document their presence or size.

Epidemiological studies are typically observational in nature, meaning that that the investigator has limited control over the exposure that study participants experience. Epidemiological studies are typically concerned about the health of populations, while clinical medicine is concerned with the health of individual persons.

In epidemiology, the term “exposure” can be method applied to any factor that may be associated with an outcome of interest. When using observational data sources, researchers often rely on readily available (existing) data elements to identify whether individuals have been exposed to a factor of interest.