Discuss about the Dietary Factors associated with reflux and Risk of Adenocarcinoma of the Esophagus and Gastric Cardia.
This paper explains the relationship between dietary factors and risk of adenocarcinoma of the esophagus and gastric cardia. It is a discussion to review evidence that dietary factors have a direct influence on the risk of having adenocarcinoma esophagus and gastric cardia. Adenocarcinoma esophagus is a type of oesophageal cancer that mostly affects the white men in the United States. Gastroesophageal reflux was recorded as the most known risk factor for adenocarcinoma esophagus (Houghton, Mangnall & Read, 1990).
For those who have had the severe symptoms for a long period of time, the risk may be more than forty-fold. GER has been observed to cause an increase of risk of gastric cardia exceeding forty-fold. Various foods, including chocolates, coffee, tomatoes, dietary fats, mints, citrus fruits, and onions have been assumed to have a strong relationship with temporary reflux mostly because of relaxation of LES.
The aim of this paper was to ascertain whether it is true that the above-mentioned foods have an association with risk of gastric cardia and adenocarcinoma esophagus. The intakes of these foods and other potential dietary behaviours were studied in a population-based study that targeted the whole nation. The design used was that of case-control with an initial 185 participants with adenocarcinoma esophagus and 258 participants with gastric cardia and a control group of 815 participants.
The study was based on Sweden population that is the native Swedish people of ages below eighty years old, who were living in the country between the 1st of December 1994 and the 31st of December 1997. The people who were considered to take part in the study were the patients found to have the adenocarcinoma esophagus as well as those that had gastric cardia. A comprehensible organization including all important departments of the hospital made it possible to have a quick and credible case study.
The results were arranged anatomically and histologically which were then analyzed by the pathologist of the study. Throughout this study, control participants were selected in a random manner from the population of the ancient Sweden people while making a consideration to maintain the gender distribution as well as the age distribution as in the cases that were already selected before.
The participants who dropped out of the study were 27 participants or 12,5% of the participants who were suffering from adenocarcinoma esophagus and 51 participants or 16.3% of participants who were suffering from cardia cancer. This nonparticipation was caused mainly by 66 patients or b4.6% of the total participants having very poor clinical health or even sudden death immediately after they were diagnosed with the adenocarcinoma esophagus or cardiac cancer (Blot, Deresa, Kneller & Fraumini, 1991). Nonparticipation from the patients in the control group was 308, which was 27% of the total number of people in the control group and this was attributed to majorly the patients' not willing to take part in the study.
There were seven participants who were dropped out of the study because their total intake of energy was more than 3SDs from mean energy intake, which resulted in their dietary responses having a lot of errors. Other three more participants were excluded because they did not have information about their Body Mass Index and a further two participants were excluded from the study because they were not responding appropriately to the given questions about their diet. After all these exclusions there were 185 participants suffering from adenocarcinoma esophagus, 258 cases of cardiac cancer and 815 participants for the control group.
All the participants went through a computer-aided interview. The interviews were conducted by professional interviewers who came from the Statistics Sweden and were carried out face to face. A structured questionnaire examining food frequency, which is a modified version of food frequency questionnaire that was evaluated before, that included 63 beverages and food items, was used to examine the dietary behaviours of the interviewee for 20 years before that interview.
The period of 20 years was chosen so as to enable the examination of risk factors with an adequate time that could cover the period of time when the cancer symptoms were still not evident. The interviewers asked the number of times each food or beverage item was consumed per day, per month and even per year., the exact time the participants usually took their last meal of the day every day and the amount of food eaten per different serving throughout a day, this was aided by showing pictures of common different portions of the seven Swedish dishes.
The relationship between food items and reflux symptoms was first analyzed for the patients in the control group. The coefficient of correlation of Spearman was used to analyze the relationship between the variables in diet and the harshness of reflux in the patients who were in the control group. The regression of unconditional logistics was used in the multivariate modelling and univariate modelling (Allen, Mellow, Robinson & Orr, 1990). All the multivariate models had inclusion of gender, age, Body Mass Index (divided according to the distribution in the control group), the alcohol intake in terms of energy content of the alcohol measured in grams taken in every week, total intakes of vegetables and fruits and the smoking of cigarette, if they have smoked in the past, if currently smoking and if they have never smoked.
The median age of the patients in study groups was 67 years. The median age of the patients in the control group was 68 years. The study group was made up of 86 per cent males and 14% females. The control group was made up of 83 per cent males and 17% females. The number of participants with a history of smoking tobacco was lowest among the participants in the control group while the numbers were larger in the participants of the study group suffering from adenocarcinoma esophagus and the number of participants with a smoking history being largest in the patients with gastric cardia. There was slightly more participants who registered alcohol drinking in the study group of patients with cardiac cancer compared to the participants in the group or the group of patients suffering from adenocarcinoma esophagus.
The medians of ten dietary factors were shown to be related to LES relaxation in participants in the control group under laboratory setting were found to be same among patients who with self-supported symptoms or without these self-supported symptoms within 5 or more years prior to the time the interview took place. The levels of the mean of the factors were also same in these two groups. The severity of reflux and Spearman's correlation of the ten dietary factors among patients suffering from reflux had a very small magnitude and all the coefficients had no visible statistical differences.
The estimated relative risk for the two types of cancer when there is exposure to the various conditions was tabulated. A statistical insignificant 40% increase in the risk of gastric cardia was seen between the intake of highest tertile of chocolate and the intake of lowest tertile of chocolate. In the cases of adenocarcinoma esophagus no noticeable trends were registered, however, an insignificant decreased risk of adenocarcinoma esophagus was noticed when there was increased consumption of leeks, onions, and garlic.
The amounts of food taken per serving and the time these foods were taken on a daily basis were found to have no relationship whatsoever with risks of the two types of cancer studied in this paper. Different adjustments made in the variable did not change the results (Szarka. & Locke, 1999).
In this study of random samples of participants from the adults from Sweden population, the recurring self-supported symptoms in the participants within five or even more years before the interviews were not taken to be related to dietary behaviours of these participants that had already been associated with the low mean basal pressure of LES or dyspepsia. In addition, the said factors were not taken to be related to the risks of gastric cardia and adenocarcinoma esophagus. From the study, it is concluded that no association was registered between dietary habits and the risk of the two types of cancer.
There could be many explanations as to why these findings did not bring out an association between gastric cardia and adenocarcinoma esophagus and the dietary factors as was found in the laboratory experiments. The first explanation could be that the intake of the foods that brought about relaxed LES or the temporary GER in the experiments carried out in the laboratory might not have been in sufficient quantities or might not have been in enough frequency to bring about a significant condition of chronic reflux. IN most of these previously performed experiments, however, used moderate size portions, which was same as the portion taken as one portion in this study, to experiment the possible association between dietary habits and reflux symptoms. The second possible explanation would be that the temporary reflux that is induced by these laboratory set exposures may be very different from actual severe reflux characterized by inflammation that comes with the GER disease (Zhang, Kurtz, Yu, Sun, Gargon, 1997).
It is understood that the regurgitation caused by food is very much less harmful compared to the transient LES relaxations- associated episodes of reflux, which usually happens when there are no neutralizing agents in a person's stomach.
It is has been observed that people who are likely to have reflux take in small amounts of those foods that are speculated to be causing the reflux symptoms, therefore, making the relationship between these foods and symptoms of reflux very week. The absence or presence of GERD does not make it impossible to test the hypothesis that the intake of foods which are known for their ability to bring about LES relaxation increases the risks of adenocarcinoma esophagus because reflux that is associated with transient LES relaxers could be asymptomatic. Furthermore, the foods that are known to promote reflux, for example, citrus fruits, onions, and garlic, may have the anticarcinogenic properties that annihilate the effects of reflux.
Therefore the results did not necessarily nullify the strong relationship between the frequency of reflux as well as the severity of reflux and risk of adenocarcinoma esophagus and gastric cardia. Although the findings show that the general consumption of the foods that promote reflux should not be a concern of public health in the larger population according to the explanations done above.
Studies of the relationship between dietary habits and adenocarcinoma and gastric cardia have not been frequent or a common study. There were four studies that had already previously been done in the design of control and case studies, which studied some aspects of dietary habits and their relationship with these two cancers (Cohen & Booth, 1975). In three out of the four studies, the participants with both adenocarcinoma esophagus and gastric cardia were combined to form a single group for study and there was no separate presentation of results for adenocarcinoma esophagus patients and gastric cardia patients.
The fourth study only the patients with adenocarcinoma participated in the study and the patients with gastric cardia were not included. The mentioned differences plus differences in the number of participants in those four studies and the study recorded in this paper makes it difficult to make comparisons between the data in the four previous studies and the data from this study.
The estimated consumption of citrus fruit in this study was however similar to those recorded by Zhang and his colleagues. An uneven but statistically significant association between intake of fat and the risk of adenocarcinoma esophagus was registered in the latter study which was not observed in the study described in this paper (Kabat, Ng & Wynder., 1993). The observation by Kabat and colleagues that there was a significant and positive relationship between total intake of fat in men and risk of combined adenocarcinomas was consistent with the findings of the study in this paper but were contradictory to what both Brown and colleagues and Tzonous and colleagues observed.
The strength of this study lies in the fact that it was based on a larger population (Szarka & Locke, 1999). All recently diagnosed cases in the base of the study were identified and they were thoroughly categorized in accordance with the site of the tumor and the histological type. This relatively broad study enabled the analysis of the two different types of cancer mentioned. An extremely random sampling of the participants for the control group eliminates any doubt that there could have been a relationship between the selected subjects and the exposures therefore, eliminating any possibility of the presence of biases in the study process.
The dietary related questions captured questions about the symptoms of reflux that were experienced many years before the time the interview took place (Cranley ., Achkar . & Fleshler, 1986). This appeared to have taken into account the biologically significant measure of GER with the ability to realize a forty-fold increase in the risk of reflux symptoms in terms of their duration and harshness. This duration of time enabled acquisition of more accurate data that can influence an informed conclusion.
There was high response rate by those who participated in the study as compared to the dietary studies that had been done before to investigate the strength of the association between foods taken and adenocarcinoma esophagus and gastric cardia (Blot , Deresa S.S., Kneller & Fraumini., 1991). However, we have no reason to assume that the rates of response between the control group and the study cases were somehow related. The inability of some of the participants to accurately recall their dietary habits is also not a legible explanation as to why the results did not support the hypothesis that certain foods increased the risk of adenocarcinoma esophagus and gastric cardia (Babka & Castell, 1973).
In conclusion, it was proved that eating of foods that were associated with relaxed LES and temporary GER were practically not related to risk of gastric cardia and adenocarcinoma esophagus.
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