Cohort Studies

Running head: COHORT STUDIES

Cohort Studies

Natalie E. McIntosh

Kaplan University

HS310

Professor Digirolamo

April 13, 2010

A prospective cohort study focuses on the current time, while retrospective cohort studies a historical occurrence through the use of information already in existence (Jekel, et.al., 2007). Prospective cohort studies require determining what will be studied, assembling a research group, gathering participants and acquiring funding for the project. In contrast a retrospective cohort study will take something such as past hospital records and examines them in order to determine something such as a certain risk group.

A prospective cohort study by Hui et.al.(1988) followed 521 women over a 6-1/2 year time period. Bone mass was measured each year and the incidents of fractures was measured by bone mass and age. All of the subjects in the study were volunteers, including persons residing in retirement homes. Any subject that had a life-threatening illness was disqualified from participating in the survey. It was determined that the rate of fracture increased with age and decreased bone density (Hui, et.al. 1988). The external validation is proof positive that as women age care needs to be taken with bone health which was the goal of the work.

Sojat et. al. (2001) performed a retrospective cohort study of mandibular fractures. The researchers utilized 5-1/2 years of records from a Toronto hospital in the quantitative research. Examined were the age, sex, drug use, alcohol use, trauma and surrounding factors that resulted in fractures of the mandible. This was the use of internal validity according to Leedy (2005). The study ultimately determined that a male, under the influence of alcohol was more likely to be in an assault situation resulting in breaking of the mandible. This type of outcome could be called external validation, or generalization to the populace (Leedy, 2005).

Both studies are effective in their own...