Write about the Introduction to Epidemiology for Paper Critique.
Title of the Journal Article
The title of this journal article is brief, precise and there is no punctuation used. It is written using simple language and the intervention/exposure can be easily identified. However, the authors of this journal article have run short of naming the associated outcome as expected. There are good examples where the associated outcome have been mentioned making the title more precise and clear. For example, a journal article authored by (Li et al., 2012; Rastogi et al., 2004) has outlined both intervention and outcome, making it easier for the reader to understand the purpose the study.
The Article Abstract
The simple requirement for an abstract is to summarize the study and it should be stand alone. Therefore, the abstract in this article has met the basic elements by clearly stating the purpose of the study, objectives of the study, the main findings of the study, the study population, the study design, and the conclusion derived from the study findings have been clearly started. Moreover, the objective of this article was to determine effects of physical activity at the lower level compared to the recommended level with lowering of risk factors associated with cardiovascular and improved functional capacity as the outcome according to (Tully et al., 2007).
The introduction part of this journal article starts by associating the exposure that is active participation in physical activity to the outcome that which is clearly started as improved health of the community. Moreover, the author went ahead and identified the gap in knowledge that exists. For example, according to (Tully et al., 2007), recommendation on the promotion of structured walking scheme and the effect on low-level physical activity are not well researched and there is a lack of proper documentation. The gap in knowledge then acts as the basis for the purpose of the research, and the research problem is derived from the gap in knowledge on the study area, some of the gap in knowledge that have been pronounced by the authors include lack of research evidence to show where pedometer has been used as adjunct to other interventions and the differential effect of as a result of varying doses of the exposure. Moreover, the statement of the problem has been clearly stated in the in the introduction part of the article. For example, in order to identify research problem and formulate the research questions, the author of this journal article has cited an article that recognizes the fact that adherence to supervised programs have recorded low results, and lack of research findings based on adherence to an unsupervised walking programs according to (Tully et al., 2005; King et al., 1995) as cited by (Tully et al., 2007). The use of other past research findings as part of the introduction part is a good move, the use of literature helps the reader to understand more about the subject area and the rationale of the study. For example, the same trend has been witnessed in the other journal articles on the same subject area, according to (Soares et al., 2015; Rognmo et al., 2012; Rostagi et al., 2004), there is an established association between physical activity such taking part in 36 minutes of walking every day with reduction in the risk of developing Coronary heart disease by 55%. In this article, the authors have emphasized on the benefits of organized walking on the health of the community. At the same time, it is worth noting that at the end of the introduction part the authors of this article have articulated the aim of their study. According to (Tully et al., 2007), the aim of the study was to establish the effect of unsupervised home-based walking at lower the existing suggested level of physical activity on the risk factors related to cardiovascular disease and functional capacity on the health of an adult practicing sedentary lifestyle using the pedometers for self-monitoring. However, there are some issues that have not been addressed in the introduction part of this article. For example, the author has not highlighted the research questions or created a good theoretical ground for the formulation of hypothesis. The studies by (Anderson et al., 2016; Shiroma et al., 2010; Hashibe et al., 2009), are exemplary examples where the authors have highlighted research questions and hypothesis in order to enable the reader to understand the rationale of the study. The same concept has been witnessed in studies conducted by (Heran et al., 2011; Chow et al., 2010; Rostagi et al., 2004), in this study in the introduction part the researchers have reviewed the different literature with a view of describing both the exposure and the outcome. Furthermore, the information has helped the reader understand the subject area and help in identification of the gap in knowledge that exists. The literature used in this journal have helped in highlighting the knowledge gap that exists within the subject area. For example, a studies conducted by (Mons et al., 2014; Meisinger et al., 2007; Rostagi et al., 2004), is a good example where the authors have stated the gap in knowledge in the introduction part.
Description of Evidence
The exposure in this study was a home-based walking program.
The expected outcome of this study was improved cardiovascular risk factors and functional capacity. The study participants carried out self-monitoring to measure the outcome using pedometers. It is worth mentioning that the researchers observed certain standard procedures during the measurement of the outcome in order to reduce the chances of measurement bias from occurring. For example, the author has clearly mentioned that during the measurement of arterial blood pressure and the heart rate the study participants were allowed to rest for 3 minutes and the measurements were taken while they were seated, in addition, the measurement was obtained using a validated tool. This was a very good move by the researchers in improving the internal validity of the research by reducing measurement bias. Moreover, the researcher baseline measurement for the lipid profile test was also done by following the recommended laboratory standard procedures, in this case, the study participants were asked to fast before their blood samples were taken for determination of the lipoproteins that included low-density lipoproteins (LDL), total cholesterol, and high-density lipoproteins. Technically this is tests that require patient to fast overnight before their determination can be carried out from the blood sample, in the absence of fasting there will be a false positive result. However, despite all the efforts put in place by the researcher in eliminating the measurement bias, it is very clear after exhaustively reading the article that the researchers of this article did not state how many enumerators were involved during the outcome measurement and whether they were trained or not, the issue is of concern because it could be a source of bias in the study. I would recommend that the measurements taken by well-trained enumerator and only one person is engaged as the enumerator in taking outcome measurements to eliminate measurement bias completely leading to improved study result validity. According to (Boccia et al., 2007), the bias are defined as systemic errors that afflict the study design and therefore negatively impacting the study validity and the overall effects will be felt as the established association based on the study findings can be challenged by others.
A randomized control trial study design was used to conduct this study. The individuals who were invited to the first session were interviewed and asked to fill a questionnaire on the lifestyle and health issues. It is very important that the authors of this article have started the inclusion and exclusion criteria that were used for recruiting the study participants. One of the basic element to be considered when determining causality in any epidemiological study assess whether the study design used is appropriate, besides good sample size and elimination of systemic error that could influence the outcome of the observed association between exposure and outcome according to (Quincy and Ragan , 2017; Bowling, 2014; Sofi et al., 2008). The decision by the researcher of this study to use the random controlled trial as the study design to determine the association between unsupervised home-based walking at lower the existing suggested level of physical activity on the risk factors related to cardiovascular disease and functional capacity on the health of an adult practicing sedentary lifestyle according to (Tully et al., 2007), is highly recommendable. Random controlled trials is highly ranked as one of the epidemiological study design that has the capabilities of providing most reliable evidence to determine association between the exposure and the outcome, this is because most of the confounding factors that could have led to study participants being exposed during the study have been eliminated by randomization according to (Salmond et al., 2016; Zaccai, 2004). However, this study design is expensive as compared to case-control studies and ethical issues are also an area of concern. It is important to recognize the fact that for this study the researchers obtained signed consent from the study participants before their lifestyle and health information was obtained and ethical clearance was sought by the researchers from Queen’s University of Belfast research ethics committee as suggested by (Tully et al., 2007). However, it is worth mentioning that randomization doesn’t perfectly yield balanced groups between the exposed and the control with respect to prognostic factors and differences due to chance has seen in the exposed group according to (Stott et al., 2012; Zaccai, 2004). In this study the authors went ahead and clearly started that randomization was achieved by computer generating random numbers and the results were concealed until after the baseline measurements was complete, the aspect of reporting the process of randomization and concealment was a good move. According to (Bowling, 2014; Kepes et al., 2014; Zaccai, 2004), one source of error in reporting randomized control trials is a lack of reporting on the method used to achieve randomization and allocation of concealment. Zaccai reported that 45% of random controlled trail journal articles obtained from a medical journal that went through systematic review lacked reporting on the process of randomization.
The participants in this study were employees of Northern Ireland Civil Service (NICS) with age bracket of 40 to 61 years. The restriction of age is one way of eradicating confounding factors, hence, this was a good move by the authors to improve the internal validity of the study. However, there was no matching between the exposed group and control. According to (Boccia et al., 2007), the use of restriction and matching are effective ways to prevent confounding in any epidemiological study. Studies by (Sattelmair et al., 2011; Rastogi et al., 2004), the concept of age restriction and matching was used to eliminate the confounders. The source of the study population has an impact on the conclusion that can be drawn from the study, selection bias can be introduced into the study based on how the participants were recruited according to (Zaccai, 2004). For example, in this study the participants were recruited into the study through the media, this can be a source of selection bias in that the level of motivation and attitude towards health issues between those who voluntary to participants and non-participants. The authors of this article have done a good job by clearly starting the inclusion and exclusion criteria that were used to recruit the participants into the study, this move helped in improving the study validity. However, the reader of this article can raise fundamental issues that regarding the lack of description of socio-demographic characteristics, I would recommend that the information on socio-demographic be included to give more information on the study participants and limit confounding. Description of the study population socio-demographics helps the reader understand the possibilities of making a statistical inference based on the study findings (Salmond et al., 2016; Boccia et al., 2007; Zaccai, 2004). The generalization of this study finding to the entire population cannot be realized due to certain issues that include lack of stratification of the study participants within the group, for instance in the control group there were only 5 males and 15 females, the results obtained from this can be misleading. It is worth noting that the author of this journal article have clearly started and explained the loss of follow-up and the attrition rate has been calculated this could help the reader in understanding the conclusion drawn from the association and exposure.
Main Findings and Discussion
The researcher has recognized the importance of reporting on the response rate that was witnessed during the period of the study which was reported as 5.6%. However, it is important to point out that the registered response rate was quite low and therefore, could not be a true representative of the initial population which was estimated to be 3000, this has negatively impact on the external validity of the study findings. Therefore, the statistical inference of this study findings can be challenged by the reader. At the same time, it is recommendable that the author has reported the issue and this can be viewed as a limitation of this study. Moreover, the researchers of this article have reported an attrition rate of 11% and the reasons for the loss of the study participants have been given. Though, it was important to report the attrition rate the reader can associate it with a source of attrition bias in the study. The effect can be felt when calculating the attribute risk, hence, resulting in decrease in the strength of association between the exposure and outcome. The researchers in this study reported significant decrease in the measurable outcome of the cardiovascular risk factors such as BMI, waist circumference, hip circumference, total cholesterol to HDL ratio for both the 3and 5 day group, but the same was not recorded among the control group. Furthermore, the researchers in this study performed independent t-test to determine if the difference in a significant changes observed between the 3 and 5 day groups were due to lack of balance between the subgroups. The decision to use the t-test was a good move because this was one of the best ways of eliminating confounding factors another possible way of removing the confounding would be through stratification. The authors reported no significant difference the 3 and 5 day in terms of the distance walked and this was proved by the results producing a p of 0.81 but 3 day group recorded increased functionality with p-value results of 0.03. The authors did well by presenting the significance of the results using the p-values, they did not go further to state the confidence interval which could have validated the study results more. However, this can only be assumed to be significantly correct if there was no bias introduced in the study, but from the scrutiny of the study method there are possibilities of bias hence the validity of the results can be challenged by the reader. For example, despite all the efforts put in place by the researcher in eliminating the measurement bias during the measurement of the outcome, it is very clear after exhaustively reading the article that the researchers of this article did not state how many enumerators were involved during the outcome measurement and whether they were trained or not, the issue is of concern because it could be a source of bias in the study. It would have been my recommendation that the measurements be taken by well-trained enumerator and only one person should have been engaged as the enumerator in taking outcome measurements to enhance the study result validity. At the same time, the data on the walking program the study participants were allowed to self-report on the steps made, the level of breathlessness, and duration of walking this could be prone to bias. It is not easy to determine the strength of association between the exposure and outcome from this study findings. The authors of this research have used ANOVA and t-test for comparing the outcome between the groups and within the groups. I would have recommended the use of multivariate analysis by controlling all the Covariates, this would be best way of eliminating the confounding factors from this study. For example, a study by (Tully et al., 2004), multivariate adjusted relative risk was calculated to measure the association between the exposure and the outcome. The results reported by the authors of this study were not able to establish a temporal relationship between the exposure and the outcome. For example, the authors reported no improvement on the level lipids such as LDL which other studies have reported as a risk factor for the development of cardiovascular diseases. However, the authors reported 15% and 11% increase in 10 m SWT distance walking for 3 and 5 days respectively. Furthermore, the reported results were consistent with other studies cited by the authors which reported 8 % to 30% increase. The reported results by the author explain the dose-response relation that exists between the exposure and outcome in this study. The existence of biological plausibility can also be supported by the reported result of improved functionality function which helps in lowering the risk of cardiovascular disease, but the validity of this results can be challenged due to confounding that could have emanated from familiarization due to lack practice test. It is worth mentioning that the author did well summarizing the study results in the opening part of the discussion section and went further to cite more literature that supports the study findings this proves the consistency of the study. However the authors didn’t cite research findings that contradict the study, this would have added more value to the discussion of the subject area.
It is very important that author stated the limitation of the study by identifying issues that include small sample size, sources of the confounding. The authors went further to give the recommendations for feature studies. Furthermore, the authors of this study went ahead to provide information on the impact of the study results and the contribution of the study findings to the study area and the conclusion was basically drawn from the study findings.
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