Research Questions and Study Design
Q1: What was the exposure or intervention?
This exploratory research study by Rastogi and his co-authors has the prime focus of evaluating the effect of regular and diligent physical activity regime on the reduction of risk factors the coronary heart disorders of the susceptible population (Rastogi et al., 2004). In this research study the case subjects were selected on the basis of having a previous history of having myocardial infarction and the control subjects were selected randomly (Rastogi et al., 2004). Now the exposure for this research study has been a leisure-time activity that is equivalent to 36 minutes of brisk walking. The researchers have attempted to judge the effect of this exposure on the risk factor of coronary heart diseases on the susceptible population selected as the subjects for the assignment (Rastogi et al., 2004).
Q2: What was the outcome?
As mentioned above, the prime focus of this study has been to judge the efficacy of physical exercise as a part of the daily regimen in reducing the risk factor of a common public health concern like coronary heart complications. The outcome of this study has been to determine the whether the leisure time activity comparable to 36 minutes of brisk walking everyday can be a protective factor resisting the occurrence or onset of coronary heart disorders in contrast to the sedentary lifestyle acting as strong contributing factors to this particular disease (Rastogi et al., 2004). The importance behind selecting this particular outcome for this study is the fact that proper data for CHD care in India is highly lacking and and lack of health promotional campaigning in Indian market is also a major reason behind the emergence of the common public health concerns in abundance in the Indian population. Out of all the control cases selected for this particular research study, 48% research participants were engaged in different levels of physical exercise and the impact of this exposure was judged on the test subjects rest whereas the rest of the 38% of the total cases were kept on a sedentary lifestyle. The distinct outcome was characterized to be a reduced relative risk indexes to 0.45 in the study subjects that were engaged in different levels of physical exercise as compared to the non exercisers or on a more elaborative note, the test subjects on sedentary lifestyle with relative risk index of 1.88 (Rastogi et al., 2004).
Q3: What was the study design?
The research article by Rastogi and his co-authors, has used a hospital based case control study to evaluate the association of regular physical exercise to the risk for coronary heart diseases in the Indian population setting. The study design has been an exploratory one, in which the impact of leisure time physical activity on the risk factor to heart complications in the susceptible population has been evaluated and standardized with contrast to non-work sedentary lifestyle (Rastogi et al., 2004).
Study Population and Main Findings
Q4: What was the study population?
The research study was aimed at determining the impact of non pharmacological intervention techniques like leisure time physical activity on reducing and managing the risk to coronary heart diseases in the susceptible population of the Indian metropolitan city (Rastogi et al., 2004). Hence the study population chosen for this particular research was selected from the hospitals from Bangalore and New Delhi, 350 test subjects were selected on the basis of having a prior medical history of acute myocardial infarction that were contrasted with 700 control subjects that chosen on the basis of their similarity to the case subject on the basis of gender, age and other confounding factors from hospitals in Bangalore and New Delhi (Rastogi et al., 2004).
Q5: What were the main findings?
In the research study under consideration in this assignment, case and control subjects were chosen on the basis of a previous history of heart disorders. As mentioned above 48 % of the research participants were involved in a leisure time activity that was equivalent to 35 to 40 minutes of brisk walking and the impact of this exposure was judged in contrast to the rest 38 % of the total cases that were kept on a sedentary lifestyle (Rastogi et al., 2004). The main findings of this research study has been clearly articulated after the sex and age adjusted analyses, the exposure to leisure time regular exercises everyday could reduce the relative risk index to 0.45 in the test subjects ((95% CI: 0.31, 0.66) in contrast to a much higher relative risk index to coronary heart diseases in the non exercising test subjects. Moreover the study could also discover that more than 3.6 hours of sedentary activities such as watching television could accumulate the relative risk of 1.88 units as compared to 70 minutes of the same per day (Rastogi et al., 2004).
Q1: Are the results likely to be affected by selection and/or measurement bias?
This particular research study has been a qualitative exploratory study that has judged a dose response between pre standardized exposure and its impact as the outcome of this epidemiological study. As this research has incorporated human subjects the outcome will be different for different individuals, and the measurement and analysis procedure will be affected by different external and internal factors that are generally associated with the research studies involving human subjects belonging to different demographics (Rastogi et al., 2004).
Measurement bias is an unavoidable consequence of any qualitative study design, and as the study design for this research article has been qualitative involving human subjects, the chances for measurement bias is high for this study. Moreover it should not escape notice that in this research carried out by Rastogi and his co-authors, the impact of the exposure was judged across levels of intensity to arrive at a more reasonable and accurate results, and hence the measurement bias can significantly be present in this situation as the outcome variable has been judged across different levels or dimensions (Rastogi et al., 2004).
Bias, Confounding, and Chance Variation
Q2: Are the results likely to be affected by confounding?
Confounders or confounding factors, as a more abundantly used term in epidemiological studies, can be defined as the external and internal factors associated with either the exposure or the study design that has the potential to alter or affect the outcome of the research study. In the article under criticism for this assignment, the exposure had been the regular leisure time activity and its impact on the relative risk to coronary heart diseases in the susceptible subjects (Rastogi et al., 2004). However there are other confounding factors like smoking, drinking, unhealthy eating habits, stress and sleeping patterns that are contributing factors to accumulation of diseases like coronary heart complication. In order to standardize the outcome verdict, some of the confounding factors have been taken into consideration in this study; however, some have escaped the notice of the researchers. Hence, the outcome of this research study can be affected by confounding factors (Rastogi et al., 2004).
Q3: Are the results likely to be affected by chance variation?
The outcome of a exploratory research study is affected by chance variation when there is a significant difference in between the expected and derived outcome. However in this particular study the researchers have gone to extreme lengths to ensure accuracy and transferability of the study, and all the data have been statistically analysis. Hence the possibility of the verdict of this study to be affected by a chance variation is low (Rastogi et al., 2004).
Q1: Is there a temporal relationship between exposure and outcome?
It has to be understood in the context of this epidemiological research, the relationship between exposure and outcome is heavily dependent on time frame. Undoubtedly the intensity of the exposure and the characteristics of the subject population being studies have a profound impact on the outcome, the time frame for which the subject population has been exposed to the intervention technique also has a altering role on the outcome generated. Hence for this particular research study there is a temporal relationship between the exposure and the outcome generated (Rastogi et al., 2004).
Q2: Is there a strong relationship between the exposure and the outcome?
The research design and execution of the research process is surely commendable, with the statistically analysed accurate data, the relationship between the exposure and the outcome has a conspicuously strong relationship. From the results and discussion section of the article under criticism in the assignment, the differential exposure to regular leisure time activity has clearly facilitated a significant reduction in the relative risk factor in the susceptible population (Rastogi et al., 2004). It must not also escape notice that many of the confounding factors like age, gender, smoking, drinking among other such activities have been carefully standardized in the statistical analysed before the verdict of the study was articulated. Hence the significant decrease in the relative risk factor to coronary heart diseases that was found in the study, i.e. 0.45 in contrast to 1.88 of the non exercising control subjects was majorly due to the exposure. Hence there is a strong relationship between the exposure and outcome which has been explained in the research in an easy to comprehend manner (Rastogi et al., 2004).
Temporal Relationship between Exposure and Outcome
Q3: Is there a dose-response relationship between exposure and the outcome?
It has to be understood that in an epidemiological study that is completely dependent on the exposure and its impact on the outcome, the relationship can easily be dose dependent. Along with that, in a research study that is completely dependent upon the impact of the exposure on the subjects the dose of the exposure selected has a profound role in outlining the outcome (Rastogi et al., 2004). Now as for this particular study, the research processes included human subjects on whom the exposure was judged across different levels of intensity to minimize the possibility of bias. Hence it can safely be concluded that as the relative risk decreased from the level for sedentary lifestyle being 1.88 to high intensity regular leisure time activity equivalent to 36 minutes of brisk walking being 0.45, the relationship between the exposure and the outcome is dose dependent (Rastogi et al., 2004).
Q4: Are the results consistent within the study?
The consistency of the result outcome due to a set exposure hints at the viability and accuracy of the research study. Now coming to the epidemiology article under criticism in this assignment, the results clearly depicted that the population set with zero leisure time activity showed signs of reduction in the risk factor, where as the subject set exposed to different levels of leisure time activity the risk factor reduced significantly. Therefore it can be safely concluded that the result of this study has been consistent and should be appreciated for the same (Rastogi et al., 2004).
Q5: Are the findings consistent with other evidence, particularly evidence from studies of similar or more powerful study design?
In any valid criticism, the verdict of the paper is judged for relatability and transferability, and these two attributes of a research paper is judged due to the fact that these two particular attributes determine the viability and validity of the study. It has to be considered Coronary heart diseases are one of the main public health concerns in this age, and the hunt for valid and viable non pharmacological interventions for reducing the risk factors for this disease (Rastogi et al., 2004). As leisure time physical activity is a very easy to implement and most effective intervention technique to facilitate healthy living in the population susceptible to diseases alike to coronary heart diseases, there can be more articles found that has similar focus.
Running is considered to one of the most effective physical exercise pursuits that can be easily implemented in the lifestyle structure of the individuals. The research article by Myers and his co-authors have devoted time and effort to determining the impact that leisure time running can bring to the mortality rates due to coronary heart diseases (Myers et al., 2015). Needless to say, this study design is very similar to the one under criticism for this assignment; however the population setting is not as alike. Moreover this article showed the benefits of 5 to 10 minutes of running at the speed of 6 mile per hour on reducing the mortality rates and facilitates easy management of this disease (Myers et al., 2015). Undoubtedly, the study design is a bit more complex and diverse than the one being criticized; the results generated are relatable to the verdict of this research study.
Another research study that can be related to the objective of the research study that is being criticized in this assignment is the exploratory metabolic study by Gielen and his co-authors. They have very clearly articulated the efficacy of physical exercise as a part of daily regimen can have on the reducing the risk top heart complications by improving the metabolic functions of the body and resisting extra cholesterol being accumulated in the body (Gielen et al., 2015). However this study has explained the data on a more molecular level rather than an epidemiological level, still the results are very similar and relatable to the article by Rastogi (Rastogi et al., 2004).
Q6: Are the results plausible in terms of a biological mechanism?
As the research study has been done on human case and control subjects, this result is absolutely plausible in term of a biological mechanism (Rastogi et al., 2004).
Q1: Can the findings be applied to the source population from which the study population was derived?
It must be mentioned that the findings of this research study is externally valid given the fact that the subject population has a history of heart complications. However this particular study is not completely generalizable as the subject population for the research study already had a prior medical history of a myocardial infarction (Rastogi et al., 2004). Although, the study can be executed on the source population on the condition of a prior medical history of heart disorders of high susceptibility to heart disorders. Hence the study can be recreated on the source population but the outcome might differ if the population or the setting is changed (Rastogi et al., 2004).
Q2: Can the study results be applied to other relevant populations?
It has to be considered that the study design for this research study has been opting out case subjects having a prior history of myocardial infarction. Hence the drawback of this research article is that the outcome cannot be applied to other relevant population setting unless the recipient population has had a prior medical history of myocardial infarction (Rastogi et al., 2004). Hence it can be concluded that the result of the research is not completely transferable as altering the population choice without considering the confounders can also alter the outcome generated (Rastogi et al., 2014)
References:
Gielen, S., Laughlin, M. H., O’Conner, C., & Duncker, D. J. (2015). Exercise training in patients with heart disease: review of beneficial effects and clinical recommendations. Progress in cardiovascular diseases, 57(4), 347-355.
Myers, J., McAuley, P., Lavie, C. J., Despres, J. P., Arena, R., & Kokkinos, P. (2015). Physical activity and cardiorespiratory fitness as major markers of cardiovascular risk: their independent and interwoven importance to health status. Progress in cardiovascular diseases, 57(4), 306-314.
Rastogi, T., Vaz, M., Spiegelman, D., Reddy, K. S., Bharathi, A. V., Stampfer, M. J., … & Ascherio, A. (2004). Physical activity and risk of coronary heart disease in India. International journal of epidemiology, 33(4), 759-767.
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