Fundamentals of Epidemiology pdf
Added on 2021-06-17
11 Pages2991 Words65 Views
1Fundamentals of EpidemiologyNameDate of Submission
2This is a critical appraisal of an article titled, ‘Acute effects of ambient temperature andparticulate air pollution on fractional exhaled nitric oxide: A panel study among diabetic patientsin Shanghai, China’, written by Li H, Bai H, Yang C, Chen R, Wang C, Zhao Z, Kan H., andpublished in the journal of epidemiology, 27(12):584-9, in the year 2017. 1.Research questions The research question being answered in this article is concerning the mechanisms involved inthe air pollution by particulate matter in presence of ambient temperatures 1. To do this therefore,the researchers determined the association between fine and coarse particulate matter, andambient temperatures during the fractional exhalation of nitric oxide, which is a biomarker ofrespiratory inflammation 2. This research question is valid and in line with the topic because theauthors have linked the problem with previous research findings to show the existing gap. Forinstance, they acknowledge the fact that previous research has shown an existence of a linkbetween temperature variations and air pollution by particulate matter in causing respiratorymorbidities and mortalities. Since most of the respiratory tract infections are associated withinflammations, nitric oxide has been chosen as a non-invasive agent to access the mechanism ofthe association between ambient temperatures and particulate matter in respiratory tract infection3. 2.Study design This article has adopted a longitudinal panel research design among a study population of peoplesuffering from type 2 diabetes mellitus in Shanghai, China. In this case, the authors justify thereasons of selecting a population of type 2 diabetes mellitus patients. In this case, they haveargued that previous studies have indicated that these patients are highly vulnerable to the stimuliof ambient temperatures because they are in a state of high inflammation. The use of this study
3design fits to answer the research question because it involves making repeated observations onthe same variables, either for a short or long period of time 4. Moreover, bearing in mind that thisstudy involves the analysis of the effects of exposure of the type 2 diabetes mellitus patients toambient temperatures and particulate matters, the actual relationship between exposure andeffects must be presented. The longitudinal study design is most commonly used to test thecause-effect relationship between different variables. In this case, repeated measures of theassociation between ambient temperatures and particulate matter was followed up among thestudy participants throughout the study period. Moreover, this design allows the collection ofboth qualitative and quantitative data to allow for proper observation on exposure and outcomesrelationship 5. However, this method is associated with drawbacks that would affect thecompletion of the research due to increased financial costs of this design requires. There couldalso be possibilities of interruptions during the follow-up of the study subjects leading to loss offollow-up across time. 3. Selection of participants This study recruited 35 type 2 diabetes mellitus people from the urban communities in ShanghaiChina, among a population of 86,000 people. However, this study sample does not look quiterepresentative of the population. This is because from a sample of 35 people, it would not besensible enough to make a general conclusion about 86,000 people. Moreover, the authors havenot presented the method used for the sample selection. It would be better if the selection methodwas indicated, alongside the equation for estimation of the sample size so that readers canunderstand how a sample of 35 type 2 diabetes mellitus patients was arrived at, and not any otherfigure 1. The inclusion of participants who had doctor-diagnosed type 2 diabetes was to ensurethat only participants who were prone to respiratory tract infections as a result of exposure to
4ambient temperatures and particulate matter which is nitric oxide were recruited in this study.Moreover, the selection of people who had a permanent residence in the study area was tofacilitate the ease of follow-up and prevent possible loss of follow-up which would in turn affectthe final findings 6. In the selection of participants, the researchers excluded people who wereactive smokers, suffering from cardiac and pulmonary infections and alcohol drinkers. This is torule out the possible respiratory tract infections and inflammation as a result of any other agentsapart from ambient temperatures and particulate matter 7. This is because the named exclusionfeatures are also known to cause infections to the respiratory tract. 4.Error Possible errors in this study could be during sampling whereby the sample size selected was sosmall as compared to the overall population of the study area. Therefore, this sample size mightnot be a representative of the concerned population 8. Selection error could also have occurred,whereby the issues of gender and age differences have not been highlighted. 5.Bias and Confounding The effect of confounding of variables is quite clear, by considering the two variables, ambienttemperatures and particulate matter (nitric oxide). While low temperatures increase, the chancesof bacterial and viral infection in the respiratory tract, the nitric oxide also causes inflammationof the respiratory tract. Therefore, there could be a possibility that the observed associationbetween the two variables and inflammation on the respiratory tract could be due, totally or inpart to these factors. Therefore, the effects of the confounding variables cause bias whenestimating the impact of the exposures 9. This could for example indicate that there is asignificant difference in the population, when in real sense no difference actually exists. Bias inthis article could be due to loss of follow-up or the observer bias.
End of preview
Want to access all the pages? Upload your documents or become a member.
Related Documents
Health Effects of Air Pollutionlg...
|9
|1927
|79