Concept of Epidemiology : Assignment
Added on - 29 Apr 2020
Running head: EPIDEMIOLOGYEpidemiologyName of the StudentName of the UniversityAuthor note
1EPIDEMIOLOGY1) Overview of the selected paperGastroesophaeal reflux (GER) is a digestive disease that affects the lower esophagealsphincter (LES), which is a ring of muscles between the stomach and the esophagus (Cook et al.,2014). GER has been found to a one of the primary cause of the esophageal adenocarcinoma.There are several dietary food products like chocolate, mint products, dietary fatty foods, coffee,onions, tomatoes and citrus fruits that are found to be partially responsible for the GER, which isassociated with the relaxation of the lower sphincter muscles (Gibson & Shepherd, 2012).Aim of the studyThis study conducted by Terry et al., (2000), aims to prove whether the dietary foodsitems are associated with the risk of gastric cardia and adenocarcinoma. Thus, there was a clearstatement of the aims of research.Study design and study populationIn order to prove the fact that dietary factor is not associated with the development ofAdenocarcinoma, the Author Terry et al., (2000), had conducted a nation based population studyin Sweden, where 185 and 258 cases of esophageal Adenocarcinoma and gastric cardia havebeen taken. 815 were taken as control. The population study contained Swedish populationbelow the age of 80 years in between 1 December 1994 and 31 December 1997. The patientswho had been newly identified with the case of Adenocarcinoma were also considered. All thepatients with squamous cell carcinoma have been avoided, as the risk of squamous cellcarcinoma is not related to GER. All the cases have been identified anatomically and histologicalby a study pathologist. Therefore, all the cases have been classified based on the site of the tumorand the histological type. Non-participation in the cases is mainly due to poor clinical conditionsor immediate death after the diagnosis. There was also nonparticipation among the controls due
2EPIDEMIOLOGYto their unwillingness to participate. Seven subjects were removed from the study due to theirerrors in the dietary information and finally the study was conducted with 185 and 258 cases ofesophageal adenocarcinoma and cardia adenocarcinoma and 815 controls. Thus, this qualitativemethod is the right methodology for addressing this research goal.Pattern of the studyThe questionnaire for the interview contained questions related to the dietary habits. 63food items and beverages have been considered for the study and the participants were enquiredabout the food habits 20 years back to avoid any political risk factors. Questions regarding themeal timings and the average size of the meal were asked by considering the photographs of thestandard Swedish 7 common dishes. The reflux symptoms have been classified as hear burn atleast once per week. The duration, intensity and the frequency of the reflux are also considered(Gibson & Shepherd, 2012). Thus, it can be seen that all the parameters for the study had beenproperly considered in this paper. The correlation between the reflux symptoms and the foodsitems have been studied only in the control subjects. The data collection method was sufficientalthough the author might have taken up a large population to avoid the chance variation.FindingsFrom the population study, it was found that the GER symptoms were not related to thedietary factors. The dietary factors were previously associated with reduction in the mean basalpressure of the LES, but it is not related to the risks of adenocarcinoma. As per the populationstudy, the dietary factors associated with LES relaxation are not related to esophagealmalignancy in any way. As per the statistical data although, transient LES is found to be closelylinked to the disease, the dietary factors have no association with the development of cancer.
3EPIDEMIOLOGY2) Appraisal of the internal validityThe exposure of this study is the dietary factors that are being predicted to have a relationwith adenocarcinoma that is the outcome of this study.The confounding factor in this study is the dietary supplements that in real did not haveany relation with the development of malignancy. A confounder is normally a variable thatactually affects the different variables in the study that affects the actual relationship. There areseveral ways to control the different confounding factors like Restriction, matching andrandomization. In this study, the author has chosen the randomization method to eliminate theconfounding factors. It can be found from the study that the adjustments due to the confoundingfactors did not affect the age-adjusted data.Presence of chance variation in the study may lead to erroneous results. It is evident fromthe study that the response rate of this study is quite low and the sample population is also large.Chance variation in a randomized control study can be managed by the increasing the populationof the participants.The participants were subjected interviews taken by the professional interviewers fromStatistics Sweden. It should be noted that 10 dietary factors were thought to be associated withLES relaxation in the laboratory settings. An increase in prevalence of gastric cardia wasobserved due to chocolate intake (Zhang, 2013). No trends of Adenocarcinoma were observedassociated to the dietary foods (Gibson & Shepherd, 2012). The meal timing and the portion sizeof the meals were also found to be unrelated to Adenocarcinoma (Zhang, 2013). It should benoted that the individuals having a tendency of GER, normally consume less amount of thosefood that causes the symptoms, which actually weakens the association of the reflux symptoms