QUT XNH355 Assignment 3 Submission on Two Journal Articles

QUT - XNH355 (2018) - Assignment 3 - Submission
Student Name:
Student number:
Research topic you focussed on:
Word count (not counting article details; strictly max. 2000):
Please do not forget to upload the PDF files of the 2 articles you have discussed
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Journal Article 1 details (first author name, journal name, year, volume, page numbers):
Jang, J., Shin, M. J., Kim, O. Y., & Park, K. (2018). Longitudinal association between egg
consumption and the risk of cardiovascular disease: interaction with type 2 diabetes
mellitus. Nutrition & diabetes, 8(20), 1-9.
What was the research question addressed in this article?
The authors assessed the longitudinal association between consumption levels of egg
and the incidence of cardiovascular diseases among Korean adults
Summary of the study design
The authors conducted a prospective cohort study that comprised of 9248 Korean
adults, who were aged 40-69 years, without cancer and cardiovascular diseases. Baseline data
was obtained from surveys that were conducted during 2001-2002, among 10030 adults
belonging to the age group 40-69 years. Following obtaining informed consent from the
participants, their dietary information was extracted that contained data on eff consumption,
with the use of semi-quantitative food frequency questionnaires (SQFFQ), at baseline and
second follow-up. Cases that pertained to cardiovascular diseases were identified, followed
by their confirmation through personal interviews. Cox proportional hazard regression helped
in calculating the hazards ratio and confidence interval.
Evaluation of assessment of the nutritional exposure
A validated semi-quantitative food frequency questionnaire (SQFFQ) was used for
retrieving dietary information from the participants. This questionnaire encompassed 106
food items. Use of this SQFFQ was an accurate step as these are regarded as the primary
method for the measurement of dietary intake, while conducting epidemiological studies
(Vioque et al., 2013). The SQFFQ is by far one of the most common food frequency
instruments that are in use. The questionnaires were used during the time period from 2001-
2002, and 2005-2006. Exhaustive information was provided on the nine response options that
were available for each food frequency. Failure of the questionnaire to determine the pattern
in which the eggs were cooked, might have added to bias in the results. Some strengths of the
assessment can be attributed to the fact that they are intended for individuals, in place of
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QUT - XNH355 (2018) - Assignment 3 - Submission
household use, which in turn facilitated the process of calculating the weighted food
frequencies of each adult. Moreover, the authors also paid consideration to the potential
confounding factors, according to the preliminary results and previous findings.
Summary of the findings
The main finding of the research was that, 570 new cases of cardiovascular
abnormalities were diagnosed among the Korean adults during the average follow-up period
of 7.3 years. Following an adjustment for the major confounding variables and risk factors,
no significant association was found between consumption levels of egg and incidence of
cardiovascular diseases e (HR: 1.14, 95% CI: 0.87–1.49, P for trend: 0.7). However, the
authors also found type 2 diabetes to exert an effect on the association. Egg intake was
significantly related to an increased risk of the disease among diabetic participants.
Furthermore, participants with highest egg intake e (4.2 ± 0.04 eggs/week) showed a 2.8
times increased risk of developing cardiovascular disease (HR: 2.81, 95% CI: 1.25–6.30, P
for trend: 0.02), upon comparison to those with low levels of egg consumption (0.1 ± 0.02
eggs/week). In addition, the authors failed to demonstrate any significant association among
participants without type 2 diabetes mellitus (HR: 1.03, 95% CI: 0.77–1.38, P for trend: 0.8).
The authors suggested that the hazards ratio and confidence interval were calculated by cox
proportional hazard regression. They also provided information on the odds ratio, to
demonstrate the association between egg intake and cardiovascular disease.
Evaluation of the level and quality of evidence
The study design was an appropriate one. The authors conducted a cohort study, the
primary aim of which is to follow a group of individuals over a period of time for
determining the rate of incidence of certain health abnormalities or risk factors that contribute
to major diseases (Woodward, 2013). The study design can be cited appropriate since the
researchers conducted a study based on prospective cohort data from previously conducted
surveys, and determined their dietary patterns to find an association between egg intake and
risks of cardiovascular disease.
Size of the study was appropriate as the researchers included 9248 Korean adults.
Presence of this large sample size provide more accurate values and smaller margin of errors.
Large number of participants also made it easier for the researchers to detect differences
between the groups. Thus, it can be stated that the large number of participants were
representative of the population.
Selection of the participants was done in an accurate way since the researchers used
data obtained from the Ansung–Ansan cohort, which were obtained from the Korean Genome
and Epidemiology Study (Shin et al., 2013). Participant selection was done in an accurate
way since the researchers collected data from the baseline and follow-up study.
However, one major limitation was related to presence of residual confounding due to
the presence of unmeasured or unknown factors in the study, in addition to the lifestyle and
dietary factor adjustments that were related with risks of cardiovascular disease. Failure to
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QUT - XNH355 (2018) - Assignment 3 - Submission
adjust such confounding variables might have exerted an extraneous influence in the design,
thereby contributing to bias (Smith, Ventura & Prince, 2013).
Further limitations can be associated with recall bias. This systematic error might
have occurred due to differences in the completeness and accuracy of the recollections of the
participants regarding their dietary intakes (Sedgwick, 2014). In addition, failure to collect
information on the pattern of egg preparation might have also produced incorrect results.
However, the overall study was a first prospective cohort analysis of the association
between egg consumption and incidence of cardiovascular disease. 95% CI indicates that
similar results are expected to be obtained on repeating the research.
Journal Article 2 details (first author name, journal name, year, volume, page numbers):
Fuller, N. R., Caterson, I. D., Sainsbury, A., Denyer, G., Fong, M., Gerofi, J., ... & Markovic,
T. P. (2015). The effect of a high-egg diet on cardiovascular risk factors in people with type 2
diabetes: the Diabetes and Egg (DIABEGG) study—a 3-mo randomized controlled
trial–. The American journal of clinical nutrition, 101(4), 705-713.
What was the research question addressed in this article?
The researchers aimed to evaluate the impact of a high- and low-egg diet, on
circulating lipid profiles (HDL cholesterol), among obese people with type 2 diabetes.
Summary of the study design
The researchers recruited 140 adult participants, diagnosed with T2D or pre-diabetes,
with BMI ≥25, followed by their randomisation to high and low egg based diets. All
participants were advised about their diet allocation and prescription for maintaining weight.
Those in the high-egg diet were asked to eat 2 eggs/day at breakfast, for 6 days/week. On the
other hand, the diet allocation in the low diet group focused on consumption of <2
eggs/week, in addition to other sources of high protein. They were advised to maintain their
activity levels. Prescribed quota of eggs were given to the participants under the high-egg
diet. On the other hand, participants with low egg-diet were given grocery voucher of
equivalent amount. Primary and secondary assessments comprised of anthropometric
measures, pathology and vital signs, 3mo and baseline measurements. Primary outcome was
related to measurement of HDL cholesterol levels. Five questionnaires were distributed to the
participants namely, the Three-Factor Eating Questionnaire-R21, the International Physical
Activity Questionnaire–short version, the Impact of Weight on Quality of Life Questionnaire-
Lite Version, The Food Acceptability Questionnaire, and a visual analog scale.
Evaluation of assessment of the nutritional exposure
The use of these questionnaires can be regarded as an appropriate step as they
measured several domains of eating behaviour that encompass uncontrolled eating, emotional
eating and cognitive restraint. The International Physical Activity Questionnaire helps in
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