What Is A Cohort Study?

A cohort study refers to medical research for investigating the cause of disease and to develop a connection between risk elements and health results. The term cohort means a group of individuals.

The name cohort suggests that this study deals with a large group of people. The groups may be prospective or retrospective. 

The researchers plan prospective studies, and they conduct the study after some time.

On the other hand, the retrospective study analyzes the existing data or information and attempts to identify risk elements for specific conditions. Explanations are limited as the researchers cannot revert to the previous stage and collect the missing information. This study is long-term and known as a longitudinal study.

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Important Facts About Cohort Studies

• Generally, a cohort study monitors a large group of people, note their exposure to particular risk elements and figure out all the hints to determine the cause of disease.
• The Nurse Health Study is an example regarding the large cohort research. It has developed several significant connections between health and lifestyles through observation of hundreds of thousands of females in North America.
• The research is also useful to recognize social elements that impact the health of an individual.

In the medical field, the cohort study is the optimal available scientific approach that measures the outcomes of risks. Through prospective cohort research, the researchers come up with a question and develop a hypothesis about the causes of disease.

Subsequently, they monitor a group of individuals called a cohort for a particular time. It can take many years.

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Researchers gather the information that can be pertinent to the illness. In that regard, their objective is to find out any change in health, which is related to the possible identified risk elements.

For instance, scientists may require participants to observe and note the particular lifestyle events during the study. Also, they may examine any probable link between lifestyle elements and the disease.

Comparison with Other Studies

In the medical research world, the researchers consider Randomized Controlled Trials RCT as the most authentic because it is the most complicated way of analyzing new interventional medicine.

However, one cannot use this study to investigate the causes of disease. Unlike RCT, a cohort study is observational. The experts monitor the events without any intervention.

In experimental research, for example, RCTs, scientists use intervention techniques. They give participants a new medicine to assess the outcomes. When someone is investigating the causes of disease, it is not ethical to knowingly expose the participant to a possible risk, which is the case during RCT.

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Nevertheless, a prospective cohort study base on observation instead of interventions. To test medicines, RCTs are the right option. The researchers use humans to test how safe and beneficial the treatment is. Thus, they end up putting humans at risk.

Notably, the disadvantages of treatment are more than benefits. This type of testing is viable when the drug has already undergone the testing phase several times. Plus, the researchers are certain that it is entirely safe to try.

Additionally, sometimes participants show a willingness to become part of the trial because they have some symptoms. And, there is a likelihood that the drug would work well on their health, and their condition will improve.

Another type of observational research is Case-Control study. It also aims to analyze the causes of disease. Yet, cohort studies are more effective than case-control research as they are generally perspective, while the case studies have a limited scope. Typically, case-studies are retrospective and do not include a large group of people.

Examples

A few cohort studies have been quite extensive and lasted a long time. Importantly, they produced relevant data that proved to be beneficial for researchers working in various fields.

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Nurses’ Health Study

It is one of the popular examples of cohort research. This was the long-term analysis of women’s health. The researchers initiated the study in 1976. The objective was to analyze the long-term implications of oral contraceptives.

The study enrolled its large second-generation group known as the Nurses’ Health Study II in 1989. Later, this study recruited its 3rd generation nurses’ cohort from different parts of the U.S. and Canada in 2010.

The nurses who were the part of the first cohort, they all were married aged 30-55 years. The purpose of cohort II and cohort III was to analyze the diversified group of women aged 20-46 years.

The scientists and researchers have succeeded in gaining essential details with the help of the Nurses’ Health Study. The Harvard School of Public Health oversaw the study. Another important stakeholder in the research was Brigham and Women’s Hospital, both the institutes are in Boston, MA.

The Nurses’ Health Study came up with a question about the lifestyle of the participant. The study has provided a great deal of information about the pros and cons of numerous elements that include a particular type of diet.

Cohort studies are valuable in determining a connection between health and environmental aspects, for example, a chemical in the air.

Framingham Heart Study

This is another notable study that included more than 5,200 men and women in the year 1948 from the region of Framingham, MA. Indeed, it is a source of data for cardiovascular risks.

The researchers employed the next cohort in 1971, while the third one in 2002. This study generated significant findings for understanding the health of the heart. Now, the researchers are working on analyzing as to how the gene can affect cardiovascular risk.

Limitations

Although a cohort study proves to be effective in analyzing the causes of disease, it has some limitations.

• Cohort studies are not suitable to find evidence for rare diseases. The case-controlled research is useful in identifying a case of disease first and then investigates the exposure to risk.
• They are not useful to identify the reasons for a sudden outbreak of diseases.

Final Word

A Cohort Study means medical research aims to investigate the cause of disease through the observational method. It recruits a large number of people and continues for an extended period of time. However, this approach is not useful to determine the cause of the sudden outbreak of disease.