Cohort Study

Describe the characteristics and design of a cohort study. Based on a disease or health
condition identified from the “2020 LHI Topics” on the Healthy People 2020 website, or an
article from the GCU library, discuss a real example of a cohort study (include the link to
the article in your post to the forum). Include the participants, exposures or treatment
groups, timeframe, and outcomes that were measured. Why is a cohort study described as
an “observational” study rather than an “experimental” study design?

Characteristics of a Cohort Study

According to Gerritsen (2014), the characteristic features that describe a cohort study
include the identification of subjects at a point when they do not possess the outcome of interest
and the comparison of the incidence of the outcome results among groups of exposed and
unexposed subjects. The process begins with a group of people (a cohort) who do not portray the
signs and symptoms of the specific disease under study. Subsequently, these individuals are
grouped based on whether or not they are exposed to potential causes or risk factors of the
disease. Additionally, the cohort is closely monitored to determine whether there are differences
between the new cases of the disease (additional outcome) and the groups found with or without
exposure (Gerritsen, 2014). Most fundamentally, the identification of these cohorts and the
differences between them occurs retrospectively or prospectively, and in each case, the
establishment of the outcome status is carried out twice.
An instance of a cohort study entails one that aimed at determining the relationship
between dietary patterns and the risk of developing type-2 diabetes. The information for the

research was obtained from seven previous studies conducted between 2004 and 2013, including
six randomized controlled trials, and one prospective cohort study. The participants in the
random control trials ranged between 82 and 1,224 individuals while those in the prospective
cohort studies were 41, 387. The exposures or treatments included the association between the
adherence to a dietary pattern and the incidence of type 2 diabetes (Office of Disease Prevention
and Health Promotion, 2019). Moreover, the time frame for the cohort study was two years,
while that of the RCTs lasted for six weeks to a median of 4 years. Consequently, the outcomes
measured included the indication that healthy dietary patterns with a high rate of different
vegetables, various fruits, and whole grains, as well as those lower in red and processed meat
significantly reduced the risk of developing type-2 diabetes. These were coupled with dietary
patterns with refined grains, sweetened beverages, and dairy products with high levels of fat.
Besides, a cohort study is described as an observational study as opposed to experimental
study design because it focuses on closely monitoring and following people from the point of
exposure to the occurrence of a particular disease (Gerritsen, 2014). This way, the calculation of
the cumulative incidences is made possible through the examination of various outcomes brought
about by one exposure.



Gerritsen, A. (2014, May 7). Cohort and Case-Control Studies: Pro’s and Con’s.