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Epidemiological Research Methods PH7106 1. Badon. Am J Epidemiol (2017) Objective of the exam: To assess how well you can apply the concepts and methods presented in this course to assess the...

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Epidemiological Research Methods PH7106
1. Badon. Am J Epidemiol (2017)

Objective of the exam:
To assess how well you can apply the concepts and methods presented in this course to assess the “quality” of the epidemiological evidence as it appears in a published observational study.
Present your answer under the following sub-headings.
1. What is the research question? (2 points)
A good answer would state the research question and judge whether it is intended to be a descriptive question, a prediction question, or a causal question being posed?

2. Describe the study population.
A good answer here would consider things like, who participated in the study? How were they selected? What was the N? (4 points)
3. Describe the exposure – how was the exposure measured?
A good answer here would be as precise as possible. It would also comment on the exposure from the perspective of the consistency assumption (3 points)
4. Describe the outcome – how was the outcome measured?
A good answer here would be as precise as possible (3 points)
5. What covariates were considered? How well were they measured?
Did they draw a DAG? Is it clear if this study is a descriptive, a prediction study or a study designed to make causal inference? A good answer here would also discuss exchangeability. A good answer would distinguish confounding, mediating, time vary confounding and potential collider variables if they are relevant to the study. (6 points)
6. Describe how the analysis was done and was it appropriate?
A good answer here would name the statistical model that was used and judge whether it was appropriate for the analysis, and why it was or was not appropriate. (2 points)
7. Describe the main finding of the paper. Other findings may also be reported if relevant
A good answer here would include the size of the effect and its associated measure of precision. (4 points)
8. Are there threats to the validity of the effect estimated in this study?
A good answer here would consider the main sources bias – confounding, selection and information. A good answer may also consider the 4 key assumptions required to make causal inference from observational data (8 points)
9. Overall conclusion - your response should include one or two final paragraphs that summarize your assessment of the article and it’s quality.
A good answer here would consider how much you “trust” these findings from this single study? How “good” is the study? Does it provide strong evidence because of its design, attention to bias and appropriate analysis? (8 points)
· Your page limit is 6 pages double-spaced with normal page margins and you must use 12 point Times Roman font. Do not include references. We will not read anything beyond the 6 pages.

oup_ajepid_kwx XXXXXXXXXX ++
American Journal of Epidemiology
© The Author(s XXXXXXXXXXPublished by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of
Public Health. All rights reserved. For permissions, please e-mail: XXXXXXXXXX.
Vol. 186, No. 3
DOI: XXXXXXXXXX/aje/kwx095
Advance Access publication:
June 22, 2017
Original Contribution
Healthy Lifestyle During Early Pregnancy andRisk of Gestational Diabetes
Sylvia E. Badon*, Daniel A. Enquobahrie, Paige D.Wartko, Raymond S. Miller, ChunfangQiu,
Bizu Gelaye, Tanya K. Sorensen, andMichelle A.Williams
espondence to Sylvia E. Badon, Department of Epidemiology, School of Public Health, University of Washington, Box 357236,
F263 Health Sciences Building, 1959NEPacific Street, Seattle, WA XXXXXXXXXXe-mail: XXXXXXXXXX).
Initially submitted April 13, 2016; accepted for publication September 13, 2016.
Previous studies have found associations between individual healthy behaviors and reduced risk of gestational
diabetesmellitus (GDM); however, the association of composite healthy lifestyle during pregnancy with GDM has not
een examined. Participants in the Omega Study (n = 3,005), a pregnancy cohort study conducted in Washington
State (1996–2008), reported information on diet, physical activity, smoking, and stress during early pregnancy. Life-
style components were dichotomized into healthy/unhealthy and then combined into a total lifestyle score (range,
0–4). Regression models were used to determine relative risk of GDM (n = 140 cases) in relation to healthy lifestyle.
Twenty percent of participants had a healthy diet, 66% were physically active, 95% were nonsmokers, and 55% had
low stress. Each 1-point increase in lifestyle score was associated with a 21% lower risk of GDM (95% confidence
interval: 0.65, 0.96) after adjustment for age, race, and nulliparity. Adjustment for prepregnancy body mass index,
prepregnancy physical activity, and prepregnancy smoking attenuated the associations slightly. Associations were
similar in normal-weight and overweight/obese women. In this study, a composite measure of healthy lifestyle during
early pregnancy was associated with substantially lower GDM risk. Public health messaging and interventions pro-
motingmultiple aspects of a healthy lifestyle during early pregnancy should be considered for GDMprevention.
diabetesmellitus; diet; gestational diabetes; life stress; lifestyle; physical activity; pregnancy; smoking
eviations: AHEI-2010, Alternate Healthy Eating Index 2010; CI, confidence interval; GDM, gestational diabetes mellitus; RR,
elative risk.
Gestational diabetes mellitus (GDM) is a common preg-
nancy complication characterized by new onset of glucose
intolerance during pregnancy (1). In the United States, the
prevalence of GDM ranges between 4.6% and 9.2% (2) and
has been increasing over the last 2 decades (3). GDM has im-
portant health consequences for both mothers and children.
Women with a history of GDM are at increased risk of GDM
in subsequent pregnancies (4) and of type 2 diabetes postpar-
tum (5). Children exposed to GDM in utero are at increased
isk of macrosomia at birth (6) and of obesity and type 2 dia-
etes in childhood and adulthood (7).
Several healthy lifestyle behaviors before and during early
pregnancy have been associated with reduced risk of GDM.
Prepregnancy leisure-time physical activity is associated with
11%–86% decreased risk of GDM (8). Adherence to a healthy
prepregnancy dietary pattern is associated with 15%–63%
decreased risk of GDM (9–11). Early-pregnancy leisure-time
physical activity is associated with 9%–49% decreased risk of
GDM (8). Dietary interventions (promoting a healthy diet) dur-
ing early pregnancy are associated with 31%–81% decreased
isk of GDM (12). Studies of smoking and GDM risk have
shown inconsistent results, but there is some evidence that not
smoking before pregnancy or during early pregnancy may be
associated with decreased risk of GDM (13–15).
Public health messaging and interventions designed to pre-
vent GDM may be more successful if multiple maternal beha-
viors are targeted (16). However, most previous studies of
maternal lifestyle before and during pregnancy have focused
on individual maternal behaviors and have not examined
healthy behaviors jointly. In a previous study investigating the
326 Am J Epidemiol. 2017;186(3):326–333
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ay 2020
association of multiple maternal behaviors before pregnancy
with GDM risk, Zhang et al. (17) found that women who were
physically active, adhered to a healthy diet, maintained a
healthy weight, and did not smoke had a 52% reduced risk of
GDM. That study focused on prepregnancy behaviors and did
not consider maternal lifestyle during pregnancy. In addition,
maternal psychosocial stress, which has been associated with
increased risk of GDM (18), was not considered as a modifi-
able maternal behavior for prevention of GDM.
Healthy maternal behaviors during early pregnancy may
help mothers maintain glucose homeostasis in response to
increased insulin resistance in the later periods of pregnancy
(19). Further, early pregnancy, an important period that co-
incides with initiation of perinatal care, provides an oppor-
tunity to affect maternal behavior and subsequent health
during pregnancy. Our objective in this study was to investi-
gate the independent and joint associations of components of
a healthy maternal lifestyle, including physical activity, a
healthy diet, nonsmoking, and low stress levels, during early
pregnancy with risk of GDM.
Study setting and study population
Data used in this study were collected as part of the Omega
Study, a prospective pregnancy cohort study designed to assess
dietary risk factors for pregnancy complications. Details about
the study design have been published previously (20). Briefly,
pregnant women initiating prenatal care at clinics associated
with SwedishMedical Center and Tacoma General Hospital in
Washington State were recruited from 1996 to 2008. Women
were eligible to participate in the Omega Study if they were at
least 18 years of age, were able to speak and read English, initi-
ated prenatal care prior to 20 weeks’ gestation, and planned to
y the fetus to term and deliver at one of the 2 study hospi-
tals. A total of 5,063 eligible women were approached, and
4,602 agreed to participate (91%). The Omega Study was
approved by the institutional review boards of Swedish Medi-
cal Center and Tacoma General Hospital. All participants gave
written informed consent.
Data collection
Study participants completed an in-person structured inter-
view at an average of 15 weeks’ gestation (standard deviation,
3 weeks). Interviews were conducted by trained study inter-
viewers. Information collected during the interview included
sociodemographic characteristics, reproductive and medical
history, and lifestyle behaviors before and during pregnancy.
Participants were followed until delivery, and trained study
personnel abstracted maternal medical records for informa-
tion on pregnancy complications (including GDM) and course
of pregnancy. Prepregnancy body mass index (weight (kg)
height (m)2) was calculated using reported height and pre-
pregnancy weight and categorized according to standard cutoffs
(underweight:<18.5; normal-weight: 18.5–24.9; overweight:
25–29.9; obese:≥30) (21).
Lifestyle score components
Leisure-time physical activity. Physical activity during the
week before the study interviewwas assessed in all participants
using the following questions: 1) “Which recreational physical
activities did you participate in during the last 7 days?,” and fo
each activity reported, 2) “How many days?” and 3) “How
much time did you spend in the activity per episode?”. Partici-
pants were provided examples of leisure-time physical activity,
including walking, swimming, jogging, weight-lifting, dance
aerobics, bicycling, hiking, and yoga. Based on activity de-
scriptions, each activity reported was matched to a metabolic
equivalent value, a measure of the energy expenditure of a
physical activity (22). Activities with metabolic equivalent val-
ues greater than or equal to 3 were considered moderate/vigor-
ous activities. The total duration of each moderate/vigorous
leisure-time physical activity reported was calculated, and dura-
tions were summed to obtain total duration of moderate/vigorous
leisure-time physical activity (minutes/week). Self-reported infor-
mation on physical activity in early pregnancy, collected using
an interviewer-administered questionnaire similar to the one we
used, had moderate validity (Spearman co
elation coefficient =
0.12–0.24) and good reliability (intraclass co
elation coefficient=
0.82) comparedwith accelerometer data recorded among pregnant
women (23, 24).
Diet. Participants were asked to recall diet over the past 3
months using a self-administered semiquantitative food fre-
quency questionnaire. Diet was scored using a modified ver-
sion of the Alternate Healthy Eating
Answered Same Day Jun 03, 2021


Perla answered on Jun 10 2021
134 Votes
Running Head: Epidemiological Research methods
Title: Epidemiological Research Methods
Student Name and Id:
Course Name and Id:
Date: 10/6/2020
Author Note
The cu
ent report is presented as part of the requirements to complete the course work.
Preface:    3
Analysis and Findings:    3
Conclusion    5
References    6
Quality of the epidemiological research is the focus issue in the cu
ent article. The detailed focus of the study is on the aspects like Healthy Lifestyle during early Pregnancy and Risk of Gestational Diabetes Mellitus. The article written by Badon, Am J Epidemiol (2017) about, “Healthy life style during early pregnancy risk of Gestational Diabest Mellitus” is critically evaluated in the cu
ent discussion.
Analysis and Findings:
1. The key research question of the entire research report is to evaluate the impact of the composite healthy life style during early pregnancy with Gestational Diabetes Mellitus (GDM). Previous research in this context has examined the relationship of the healthy lifestyle with the risk of the GDM, however there is no any specific research done to evaluate the relationship with the complex healthy life styles during pregnancy with the risk of gestational diabetes Mellitus. The research question is aimed to investigate the same. The question is going to make prediction based on the statistical and systematic cohort research conducted on numerous subjects to associate their composite healthy life styles with the actual risk of Gestational Diabetes Melitus (GDM).
2. The study population in the cu
ent research question are pregnant women with age from 32 years to 35 years with standard deviation of about 4 to 5year. All these pregnant women selected for the research were altogether 3005 in number and they do make up the study population for the cu
ent case. General profile of the population is like most of the participants in the research analysis are educated white woman and also the population is not totally diversified in the socio-economic status perspectives. They are selected from medical centres of Washington area as they are attending for pregnancy and prenatal care needs between 1998 to 2006.
3. Exposure and measurement – in the cu
ent case the actual objective is to relate the composite healthy and ill-healthy life styles with the possible risk of the GDM. Healthy and ill-healthy exposure of the population is measured in terms of their life style activities (Leisure time physical activities), Diet of the individuals, smoking of the individuals and stress the people are facing there. Each of these practices are quantified based on standard scores and these scores are further employed for the sake of estimation of the actual healthy life style scores and these scores are employed as basis and criteria for the sake of estimation of their actual exposure and measurement of the same. The...

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