Masters of Health Science for Heart Disease- MyAssignmenthelp.com

Question: Discuss about theMasters of Health Sciencefor Coronary Heart Disease. Answer: Overview Rastogi et al., (2004) conducted a hospital based case control study to investigate the association between physical exercise, non-work sedentary lifestyle (such as watching television for greater than 3.6 hours per day) and the coronary heart disease (CHD) in India. The exposure includes leisure-time exercise, which may involve 36 minutes of brisk walking. The outcome is the low risk of CHD due to leisure-time exercise and positive association between sedentary lifestyle and risk of coronary heart disease. The study population is the patient represented in the eligible cases belongs to the age range 21-74 years. The inclusion criteria for the patients was diagnosis of incident acute myocardial infarction and in one of the 8 hospitals in urban hospitals in Bangalore and New Delhi between 1999-2000. For the study purpose data was collected from 350 cases of acute myocardial infarction. The controls comprise of 700 and were matched on gender, age, and hospital in Bangalore and New Delhi. The data collection instrument used was interview that lasted for 25 minutes. To control for the matching as well as other risk factors conditional logistic regression was used (Rastogi et al., 2004). The study findings showed that when compared with 38 % of the cases, 48% of the controls participated in some form of exercise in leisure time. In the analysis where sex and age was adjusted, the highest level of leisure time exercisers had a relative risk of 0.45 in comparison to the non-exercisers. These findings of relative risk at 95% confidence interval had value: 0.31, 0.66. The participants with high level of leisure time exercise had greter than 145 metabolic equivalents minutes per day which is equivalent to brisk walking for 36 minutes per day. The findings from the multivariate adjustment showed no alteration in the association for other risk factors. The findings showed that an elevated risk of coronary heart disease had positive association with the non-work sedentary activities. In these participants, the elevated risk of 1.88 in multivariate analysis was observed when compared to sedentary activities of less than 70 minutes per day (Rastogi et al., 2004). These finding s conclude that indulging in leisure time exercise was protective for risk of coronary heart disease, which may include as brisk walking of 35-40 minutes per day. Non-Casual Explanation of the Exposure and Outcome In the case control study the impact of the regular physical activity, sedentary activity on the patients with acute myocardial infarction was assessed. In the 350 cases matched to the 700 controls, each case chosen for trial is was compared to two consecutive controls. Those engaged in physical activity showed risk of CHD when compared to those engaged in sedentary activity. The exposure and the outcome may not be having any non-casual relationship. However, the outcome and the intensity may be effected by some confounding factors. In any qualitative study, measurement bias is common to be present (Szklo Nieto, 2014). In this study, the measurement bias is not completely eliminated by the author. The study measures the exposure at different levels. In this case it is the duration of physical activity which means that the leisure time for exercise for each participant may be different. There is a significant risk of measurement bias when a particular variable is measured on different level that consequently effects the outcome (Yin, 2013). The outcome of the study is likely to be effected by the confounders in case control study design (Dimaggio, 2013). In this study, the author has only emphasised on the physical activity such as leisure time exercise or physical activity that may be equivalent to 36 minutes of brisk walking. The researcher have adjusted the result for gender, age, and hospital in Bangalore and New Delhi. However, while studying the impact of the exposure on the coronary heart disease risk the author did not emphasise on the confounding factors such as dietary habits, smoking, and other similar activities. For instance, it may happen that a patient of acute myocardial infarction engaging in brisk walking or any other leisure time exercise may simultaneously engage in eating high calorie or fat rich food. It will consequently affect the outcome, as these are substantial risk factors of CHD. These confounders have the risk of introducing bias and where standardised to some extent in the process of data analysis. The author did not consider the genetic factors or lifestyle factors previously present in the patients of acute myocardial infarction. The results are likely to be effected by the selection of the control and different recall among cases. The selection of the participants based on hospital instead of the population based can introduce bias. It may be due to the biased view of the incidence of CHD in a hospital when compared to the selection based on entire population. The selection of the control and the cases exclusively from the hospital. The controls were suspected to have CHD but may also have other diseases. Therefore, they may have different characteristics when compared to the cases of acute myocardial infarction. The controls may engage in health promoting activity such as change in diet and lifestyle choices. Chance variation refers to difference in the expected and the observed outcome in the research study (Szklo Neto, 2014). The paper Rastogi et al., (2004) tested the hypothesis that engaging in leisure time exercise when compared to the non-work sedentary activities reduces the risk of CHD in the patients with acute myocardial infarction. In the analysis where sex and age was adjusted, the highest level of leisure time exercisers had a relative risk of 0.45 in comparison to the non-exercisers. These findings of relative risk at 95% confidence interval had value: 0.31, 0.66. The participants with high level of leisure time exercise had greter than 145 metabolic equivalents minutes per day which is equivalent to brisk walking for 36 minutes per day. Since the results were statistically significant, the hypothesis was proved. Hence, there is low risk of chance variation. If the author would have controlled more variables instead of gender and age the risk of chance variation may have be en eliminated (Szklo Nieto, 2014). Analysing Exposure and Outcome There is a temporal relationship between the exposure and outcome as the exposure precedes after the development of the disease (Yin, 2013). The exposure is given after the diagnosis of acute myocardial infarction. Therefore, the exposure influences the risk of development of the coronary heart disease. With the help of intervention say leisure time exercise the changes in the heart rate and cardiac output, changes in the blood pressure, increase in the insulin sensitivity in the can be monitored which helps establish a relationship between the exposure and outcome (Rastogi et al. 2004). In this study, a strong relationship between the exposure and outcome was found. As obtained from the data analysis, the exposure has reduced the risk of concerned outcome. In case patients with acute myocardial infarction participated in the leisure, exercise showed decreased risk of CHD. On the other hand, the participants engaged in non-work sedentary activities where found with increased risk of CHD. The study findings showed that when compared with 38 % of the cases, 48% of the controls participated in some form of exercise in leisure time. In the analysis where sex and age was adjusted, the highest level of leisure time exercisers had a relative risk of 0.45 in comparison to the non-exercisers. The participants with high level of leisure time exercise had greter than 145 metabolic equivalents minutes per day which is equivalent to brisk walking for 36 minutes per day. The findings showed that an elevated risk of coronary heart disease had positive association with the non-work sedentary activities. In these participants, the elevated risk of 1.88 in multivariate analysis was observed when compared to sedentary activities of less than 70 minutes per day (Rastogi et al., 2004). It is this difference in the outcome between the case study subject and the control indicates strong relationship between the exposure and outcome. When different level of exposure regulates the outcome, it is referred to dose respondent relationship (Calvo et al., 2016). In research, involving human subjects the outcome generated can be influenced by multiple factors. To minimise the bias introduced by the confounding factors, the leisure time exposure and its effect on reduction of risk of CHD were assessed at different durations. For instance, 10 minutes of brisk walking may not have effect similar to 30 minutes of brisk walking and its consequent impact on risk of CHD. Similarly, the sedentary activities of more than 70 minutes a day have more risk of CHD then low level of sedentary activities. These findings of relative risk at 95% confidence interval had value: 0.31, 0.66 (Rastogi et al., 2004). This is clearly indicative of dose response relationship. It can be concluded from the data analysis and the discussion supported with relevant literature that the study results were consistent in terms of the exposure and the outcomes. In the case study population there was no reduction in the risk of CHD due to leisure time exercise. With the increase in the time of participation in physical activity, the participants showed low risk of CHD. Hence, in this study there is an inverse relationship between the exposure and outcome. Therefore, the results are consistent within the study (Rastogi et al., 2004). The study findings were supported with relevant literature and other specific findings pertaining to the chosen area. The reduction in the risk of CHD due to leisure time exercise that is equivalent to 36 minutes of brisk walking was compared to the large prospective study of US women where the results showed that brisk walking for more than 3 hours a week reduces the risk of CHD by 30-40%. Similar results were obtained with large prospective study of US men by Manson et al. in the year 1999 (Rastogi et al., 2004). The results of this case control study is also consistent with the data from Israeli Ischemic Heart Disease study conducted Eaton et al. in the year 1995 (Rastogi et al., 2004). This Israel based study indicated that among middle-age men leisure-time exercise (except for work related activity), significantly reduces the risk for CHD and all cause mortality. These findings were statistically significant in regards to the inverse relationship deduced (Rastogi et al., 2004). The research by Gielen et al., (2015) who also worked on same hypothesis as Rastogi et al., (2004) indicated improvement in metabolic functions of the body due to physical exercise and reduction in the risk of heart attack. This study explained the data more on molecular level instead of the exposure- outcome relationship. In the research article by Lee et al. (2014) the positive effect of the leisure time running on CHD were clearly demonstrated. The results were similar to Rastogi et al., 2004. The running intervention was evaluated for 5 to 10 minutes of running at 6 mile per hour speed and found to reduce mortality due to CHD. However, this study design was quite different from that of Rastogi et al., 2004. In conclusion the study findings are consistent with the evidence from studies of similar study design cited in this study and more powerful study design not cited in this study. Further, the author explained the benefits of the physical activity that facilitates reduction of CHD risk such as improved endothelial function, elevation in high-density lipoprotein levels, lowering of blood pressure, improved endothelial function, reduced atherogenic cytokine production and increased insulin sensitivity. These explanation was supported by relevant literature (3 studies) pertaining to the area and other study with similar research design, exposure and outcomes. These explanation was also cited by similar other research conducted by Calvo et al. (2016) who conducted a prospective case control study to investigate the emerging risk factors and the doseresponse relationship between physical activity and lone atrial fibrillation. Therefore, this result is plausible in term of a biological mechanism. Validity of the Results The findings are valid for population diagnosed with acute myocardial infarction and susceptible to CHD. The findings are not generalisable. The selected participants in the study were already diagnosed with acute myocardial infarction. The study can be executed with people diagnosed with different heart disorders and severity where the inverse relationship between exposure and the outcome deduced by Rastogi et al., 2004 couldnt be applied to the source population from where the study population was derived. It cannot be generalised because in order to do so same exposure should be given to different population in different setting and must receive same outcome (Yin, 2013). Same exposure and outcome relationship may not be obtained if the participants are not having history of acute myocardial infarction. Similarly, the study findings are not applicable if the participants have other health disorders in addition to the myocardial infarction. The case and the control were exclusively selected from the hospital in Bangalore and New Delhi. The characteristics of the hospital patients may differ from the general population. The change in the research setting may alter the results completely. Moreover, the study is also not applicable to other relevant participants who are younger or older than the participants chosen by Rastogi et al., (2004). It can be applicable only if the characteristics of partciopants in this study is similar to other relevant population. However, it can be generalisable if the participants are chosen from the population-based study instead of the hospital-based study. References Calvo, N., Ramos, P., Montserrat, S., Guasch, E., Coll-Vinent, B., Domenech, M., ... Falces, C. (2016). Emerging risk factors and the doseresponse relationship between physical activity and lone atrial fibrillation: a prospective casecontrol study. EP Europace, 18(1), 57-63. Dimaggio, C. (2013). Introduction. In SAS for Epidemiologists (pp. 1-5). Springer New York. Gielen, S., Laughlin, M. H., OConner, 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. Lee, D. C., Pate, R. R., Lavie, C. J., Sui, X., Church, T. S., Blair, S. N. (2014). Leisure-time running reduces all-cause and cardiovascular mortality risk.Journal of the American College of Cardiology,64(5), 472-481. 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. Szklo, M., Nieto, J. (2014). Epidemiology. Jones Bartlett Publishers. Yin, R. K. (2013). Case study research: Design and methods. Sage publications.