Critical Appraisal of an Article on Higher Regular Coffee and Tea Consumption and Reduced Endometrial Cancer Risk

Running head: INTRODUCTION TO EPIDEMIOLOGY
Introduction to Epidemiology
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1INTRODUCTION TO EPIDEMIOLOGY
Introduction- critical appraisal of an article can be described as a systematic process
which evaluates the strengths and the weakness of a study or a research article. This is done to
assess to research findings and he validity of the findings. The most important part of a critical
appraisal of a study is the proper evaluation of the research questions whether the study design is
carried in a proper way and it also takes into account of the several key methodologies that are
featured in a design. The other factors that are also considered include the applicability of the
statistical methods used and the subsequent interpretation methodology used in the study process
(Patterson & Dawson, 2017). In this study an article titled “Higher regular coffee and tea
consumption is associated with reduced endometrial cancer risk” will be critically appraised.
This critical appraisal will include the overview of the journal, appraisal of internal validity of
the findings, appraisal of the causality inference, and the appraisal of the internal validity.
Overview of the journal- The chosen article focuses on the regular higher consumption
of tea and coffee leads to the reduction of the cancer risk. As per the American Cancer Society in
the year 2007, a total of 39080 women were diagnosed with the endometrial cancer and a total of
7,400 women are found to be dying from the endometrial cancer. The risk factors established in
the case study all direct towards the hormonal aetiology. Several factors like the late menopause,
obesity, infertility and early menarche has its relations with the increased exposure to the
endogenous oestrogen. Thus, an important inference is that all these factors are related directly
with the endometrial cancer. However, it is important to note that the obesity has it direct link
with the endometrial cancer and it occurs specifically in women that is undergoing post
menopause changes. Similarly, a reduced incidence of the endometrial cancer is noticed within
the pregnant women due to the high levels of progesterone secretion and in comparison to the
oestrogen. A large number of studies are done on the effect of diet on the endometrial cancer.

2INTRODUCTION TO EPIDEMIOLOGY
However, only few studies have focussed on the consumption of tea and coffee and its impact on
the endometrial cancer. The important part is that the globally both tea and coffee are widely
consumed. The substantial sources of lignans, isoflavins, cathechins, flavonoids and the other
polyphenolic compounds. It has been shown in experimental studies that polyphenols are potent
in inhibiting the carcinogenesis through the anti-inflammatory, anti-hormonal and anti-oxidant
mechanisms. However, it is also important to mention that these beverages also contain a large
amount of caffeine which has the potential of affecting the cell processes and is both the inhibitor
and promoter of carcinogenesis (McCann et al., 2009).
Materials and methods used in the study- The study was carried out in a Roswell Park
Cancer Institute in New York and the data are collected through a Patient Epidemiologic Data
Systems (PEDS). The data were collected from the span of 1982 to 1998 and it the data
collection was approved by the International Review Board. During this time period,
questionnaires were offered to the patients. It is important to highlight that the PEDS
questionnaire is self-administered. PEDS questionnaires are used to cover the information on the
diet, vitamin usage, medication, medical histories, reproductive histories, environmental
exposures, occupational exposure, family history of cancer, alcohol and tobacco consumption.
All the statistical analysis is carried out in a SAS version 9.1 in windows. For this study only
women are selected that have the complete data on tea, decaffeinated coffee, and data on coffee.
Thus, a total of 512 control and 513 cases of were included in the study (McCann et al., 2009).
Results of the study- the results of the study indicate that with the consumption of more
than 2 cups of coffee per day, within both the heavier and the normal weight women shows a
slight reduction in the overall reduction of the endometrial cancer risk. This founding is a
analysis conducted through an stratified analysis. While in the unstratified analysis, no

3INTRODUCTION TO EPIDEMIOLOGY
relationship has been found between the consumption of the decaffeinated coffee and the
endometrial cancer. The coffee consumption has positive effects on the reduction of cancer only
in the heavier women. It has been
Discussion- the discussion section highlights that the authors have noticed an inverse
association between the consumption of tea and coffee and the endometrial cancer risks.
However, no association has been noticed in the consumption of the decaffeinated coffee.
However, it is important to mention that the caffeine has a positive role in the aetiology of the
endometrial cancer. The estimates observed with the consumption of the tea and coffee has a
very similar type of analysis found for tea alone. This suggests that tea alone is much more
effective than the coffee (McCann et al., 2009).
Appraisal of internal validity-To put it briefly, this study is robust and well-designed
analysis of hospital based case study which intends to improve on previous research performed
in the area of endometrial cancer risk. Studies have suggested that endometrial cancer risk is
related to the dietary habits of an individual (Lukic et al., 2018). According to the author of this
study, few research has been dedicated to study the effect of tea and coffee on endometrial
cancer risk. Hence, this study enhances, improves and add new value to the field and not a
derivative study. However, this study has some flaws regarding validity and reliability of the
results and data.
The data source used for this study was data collected from Roswell Park Cancer Institute
(Buffalo, New York) for the duration of 1982 and 1988. They used consumption of caffeine and
black tea as independent variable. As an independent variable, they used different measure of
caffeine and tea consumption for the study of dependent variable which is the risk of endometrial
cancer. Although, the researchers have little control over the data as it is collected from Roswell