Dilemma of cohort study-A concept of early disease markers for measured risk factors.

Cohort studies use a research design that clarifies the risk fac-tors for certain diseases. Cohort studies include prospective research that follows a population, in a forward direction for a certain period of time, in which the endpoint of interest to the researcher has not occurred and retrospective research that follows, in a backward di-rection, a population that includes some part of the population who has experienced the endpoint of interest, for a certain period of time. The endpoints of interest to researchers specializing in prosthodon-tics include life prognosis (death), weight loss (nutritional deficiency), development of aspiration pneumonia, decline in cognitive func-tion, development of dementia, and appearance of gastrointestinal tract symptoms. Normally, at the start of a study, it is unclear whether there is a relationship between a risk factor and the endpoint, and researchers conduct cohort studies to clarify these causal relation-ships. Therefore, cohort studies are academically recognized as re-search methods that provide causal relationships, and several have been published in this journal.