Observational study designs for examining smoking and lung cancer

¶ … Smoking and Lung Cancer

Cohort, cross sectional, and case-control studies are together known as observational studies. These studies are frequently the only feasible manner of analyzing certain problems (Mann, 2003). In this particular case, the observational studies shall concentrate on smoking together with lung cancer.

COHORT STUDY

This is the most appropriate manner of establishing the condition's prevalence and natural history.

Conducting Study

A group of individuals that do not have the desired outcome shall be selected. Several variables, which may be significant to the condition's development shall then be measured by the researcher. The individuals in the selected sample are monitored over a length of time to observe if they develop the desired outcome (lung cancer). For the two cohorts utilized, one group shall have actually been exposed to or been smoking while the other has not, thus serving as an external control (Mann, 2003; Chen et al., 2010).

Advantages and Disadvantages

Advantages

1. Given that potential causes are assessed by cohort studies prior to the occurrence of the outcome, the study is able to show that these "causes" come first before the outcome, thus evading the dispute regarding which is the cause and which is the effect (Mann, 2003).

2. Several outcome variables could be assessed by one study (Mann, 2003).

Disadvantages

1. Where a particular outcome is unusual, then a potential cohort study is not efficient.

2. There is loss of various subjects to follow up.

3. In cases whereby there is comparison of two cohorts, one shall have been exposed to the agent of interest while one is not. The incapability of controlling all other aspects, which may vary between the two groups is the main disadvantage (Mann, 2003).

CROSS SECTIONAL STUDY

This is majorly utilized to determine incidence. Incidence corresponds to the quantity of cases in a given population at a given time (Mann, 2003).

CASE-CONTROL STUDY

Unlike the other two types of studies, this type of study is normally retrospective. Individuals having the desired outcome are matched with a group that does not have the desired outcomes. The investigator then retrospectively establishes the individuals that were exposed to the cause or treatment or incidence of a variable in all the sample groups (Mann, 2003).

Conducting Study

The investigator comes up with a hypothesis about smoking and lung cancer and later chooses what shall be determined and how it shall be determined. The investigator shall identify the study group's traits and then determine how to come up with a suitable control group and then make a comparison of the two groups to all the variables (Mann, 2003; Brenner et al., 2010).

Advantages and Disadvantages

Advantages

1. In case of rare conditions, case control studies produce a lot of data from somewhat a small number of subjects.

2. More resources are available for research given that comparatively few subjects are needed (Mann, 2003).

Disadvantages

The main disadvantage is bias, which might take two forms:

1. Observation and Recall Bias: As the research retrospectively evaluates predictor variables, there is immense likelihood for a biased evaluation of their existence and importance by the researcher or patient, or even both.

2. Sampling Bias: The patients having the disease or the control might be biased (Mann, 2003).