Fundamentals of Epidemiology Lecture Series on CCTC: For Better Study Design and Interpretation of Epidemiological Studies

ABSTRACTIntroduction: The increasing prevalence of diabetes in the world led to an increase in cases of amputation due to diabetes complications. Epidemiological studies reported more than one million amputations are performed on people with diabetes each year. Therefore, prevention and appropriate management of lesions of the foot is the most important thing. The development of wound care is growing very rapidly in the world of health.Objective: This study aimed to compare the motivation of the use of modern dressings in patients with diabetic ulcers in the Wonolopo and Kalijirak villagedistrict of Karanganyar.Methods: This study is a comparative analytical study design to compare the motivation of the use of modern dressings in patients with diabetic ulcers in the Wonolopo and Kalijirak village district of Karanganyar.Respondents: The study sample was taken from the population of people who have diabetic ulcers in the Village Kalijirak as much as 20 and as many as 20 Wonolopo village.Results: Based on the results of independent sample t test with SPSS for Windows series 18 with α = 5% (0.05), obtained p equal to 0825 which means p> 0.05 it indicates that Ha is not accepted, which means there is no difference in motivation to use modern dressings in patients with diabetes mellitus with diabetic ulcers among respondents in the Village and Village Wonolopo Kalijirak.Keywords: Motivation, Modern dressings, Wound care

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Design and implementation of observational studies to measure disease burden with a focus on stroke

International Journal of Stroke ◽

10.1177/1747493017743800 ◽

2017 ◽

Vol 13 (2) ◽

pp. 157-165

Author(s):

George Howard ◽

Virginia J Howard

Keyword(s):

Cohort Studies ◽

Study Design ◽

Observational Studies ◽

Disease Burden ◽

Epidemiological Studies ◽

Cross Sectional ◽

Surveillance Studies ◽

Design And Implementation ◽

Design Considerations ◽

Cross Sectional Studies

Observational epidemiological studies have the dual goals of measuring disease burden and assessing the association between exposures and outcomes. This report focuses on the first of these goals and provides an overview of design considerations of commonly used approaches, specifically community surveillance studies, cross-sectional studies, and longitudinal cohort studies. Each of these designs has strengths and weaknesses, with no study design being superior in all cases. Rather, these designs are complementary to achieve a better understanding of the burden of stroke.

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The swedish athletics study: design of a protocol for large-scale epidemiological studies in individual sports

British Journal of Sports Medicine ◽

10.1136/bjsm.2011.084038.124 ◽

2011 ◽

Vol 45 (4) ◽

pp. 354-354 ◽

Cited By ~ 1

Author(s):

J. Jacobsson ◽

T. Timpka ◽

J. Ekberg ◽

J. Kowalski ◽

S. Nilsson ◽

...

Keyword(s):

Study Design ◽

Large Scale ◽

Epidemiological Studies ◽

Individual Sports

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Exposure to Vitamin D Fortification Policy in Prenatal Life and the Risk of Childhood Asthma: Results From the D-Tect Study

Nutrients ◽

10.3390/nu11040924 ◽

2019 ◽

Vol 11 (4) ◽

pp. 924

Author(s):

Thorsteinsdottir ◽

Maslova ◽

Jacobsen ◽

Frederiksen ◽

Keller ◽

...

Keyword(s):

Vitamin D ◽

Study Design ◽

Childhood Asthma ◽

Proportional Hazards ◽

Epidemiological Studies ◽

Vitamin D Insufficiency ◽

Cox Proportional Hazards ◽

Small Sample ◽

Increased Risk ◽

Small Sample Sizes

Prenatal vitamin D insufficiency may be associated with an increased risk of developing childhood asthma. Results from epidemiological studies are conflicting and limited by short follow-up and small sample sizes. The objective of this study was to examine if children born to women exposed to the margarine fortification policy with a small dose of extra vitamin D during pregnancy had a reduced risk of developing asthma until age 9 years, compared to children born to unexposed women. The termination of a Danish mandatory vitamin D fortification policy constituted the basis for the study design. We compared the risk of inpatient asthma diagnoses in all Danish children born two years before (n = 106,347, exposed) and two years after (n = 115,900, unexposed) the termination of the policy. The children were followed in the register from 0–9 years of age. Data were analyzed using Cox proportional hazards regression. The Hazard Ratio for the first inpatient asthma admission among exposed versus unexposed children was 0.96 (95%CI: 0.90–1.04). When stratifying by sex and age, 0–3 years old boys exposed to vitamin D fortification showed a lower asthma risk compared to unexposed boys (HR 0.78, 95%CI: 0.67–0.92). Prenatal exposure to margarine fortification policy with extra vitamin D did not affect the overall risk of developing asthma among children aged 0–9 years but seemed to reduce the risk among 0–3 years old boys. Taking aside study design limitations, this could be explained by different sensitivity to vitamin D from different sex-related asthma phenotypes in children with early onset, and sex differences in lung development or immune responses.

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Cannabis use and misuse prevalence among people with psychosis

The British Journal of Psychiatry ◽

10.1192/bjp.187.4.306 ◽

2005 ◽

Vol 187 (4) ◽

pp. 306-313 ◽

Cited By ~ 140

Author(s):

Bob Green ◽

Ross Young ◽

David Kavanagh

Keyword(s):

Study Design ◽

Epidemiological Studies ◽

Cannabis Use ◽

Consumption Patterns ◽

Small Scale ◽

Prevalence Estimates ◽

Sample Data ◽

Low Prevalence

BackgroundIncreasing attention has been given by researchers to cannabis use in individuals with psychosis. As psychoses are relatively low-prevalence disorders, research has been mostly been restricted to small-scale studies of treatment samples. The reported prevalence estimates obtained from these studies vary widely.AimsTo provide prevalence estimates based on larger samples and to examine sources of variability in prevalence estimates across studies.MethodData from 53 studies of treatment samples and 5 epidemiological studies were analysed.ResultsBased on treatment sample data, prevalence estimates were calculated for current use (23.0%), current misuse (11.3%), 12-month use (29.2%), 12-month misuse (18.8%), lifetime use (42.1%) and lifetime misuse (22.5%). Epidemiological studies consistently reported higher cannabis use and misuse prevalence in people with psychosis.ConclusionsThe factor most consistently associated with increased odds of cannabis prevalence was specificity of diagnosis. Factors such as consumption patterns and study design merit further consideration.

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The household contact study design for genetic epidemiological studies of infectious diseases

Frontiers in Genetics ◽

10.3389/fgene.2013.00061 ◽

2013 ◽

Vol 4 ◽

Cited By ~ 14

Author(s):

Catherine M. Stein ◽

Noémi B. Hall ◽

LaShaunda L. Malone ◽

Ezekiel Mupere

Keyword(s):

Infectious Diseases ◽

Study Design ◽

Epidemiological Studies ◽

Household Contact

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Mathematical modeling of directed acyclic graphs to explore competing causal mechanisms underlying epidemiological study data

10.1101/19007922 ◽

2019 ◽

Author(s):

Joshua Havumaki ◽

Marisa C. Eisenberg

Keyword(s):

Epidemiological Study ◽

Study Design ◽

Simulated Data ◽

Population Level ◽

Obesity Paradox ◽

Epidemiological Studies ◽

Directed Acyclic Graphs ◽

Causal Mechanisms ◽

Acyclic Graphs ◽

Study Results

1AbstractAccurately estimating the effect of an exposure on an outcome requires understanding how variables relevant to a study question are causally related to each other. Directed acyclic graphs (DAGs) are used in epidemiology to understand causal processes and determine appropriate statistical approaches to obtain unbiased measures of effect. Compartmental models (CMs) are also used to represent different causal mechanisms, by depicting flows between disease states on the population level. In this paper, we extend a mapping between DAGs and CMs to show how DAG–derived CMs can be used to compare competing causal mechanisms by simulating epidemiological studies and conducting statistical analyses on the simulated data. Through this framework, we can evaluate how robust simulated epidemiological study results are to different biases in study design and underlying causal mechanisms. As a case study, we simulated a longitudinal cohort study to examine the obesity paradox: the apparent protective effect of obesity on mortality among diabetic ever-smokers, but not among diabetic never-smokers. Our simulations illustrate how study design bias (e.g., reverse causation), can lead to the obesity paradox. Ultimately, we show the utility of transforming DAGs into in silico laboratories within which researchers can systematically evaluate bias, and inform analyses and study design.

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Introduction to epidemiological study designs

Practical Psychiatric Epidemiology ◽

10.1093/med/9780198515517.003.0005 ◽

2003 ◽

pp. 85-95 ◽

Cited By ~ 1

Author(s):

Tamsin Ford

Keyword(s):

Study Design ◽

Random Error ◽

Epidemiological Studies ◽

Human Populations ◽

Key Factors ◽

Advantages And Disadvantages ◽

Prevalence Of Depression ◽

Study Designs ◽

Larger Sample ◽

Over Time

Epidemiologists must have a sound understanding of the principles of study design. Ethical considerations naturally prevent us from allocating potentially harmful exposures on an experimental basis in human populations. Observational studies are inherently more vulnerable to the effect of bias and confounding. However, these problems can be minimized by good study design. The design (and analysis) of a study aspires to maximize the precision and validity of its findings. The precision of an estimate of the prevalence of depression in a population will be reduced by sampling and measurement error. These errors are generally random, that is equally likely to deviate from the truth in either direction. Precision can be improved with larger sample sizes and more accurate measures. Confounding and bias lead to non-random error; that is the effect of the bias or confounder is systematic, tending mainly in one direction, thus reducing the validity of a finding. Choices of study design and measurement strategy are key factors in minimizing non-random error and maximizing the validity of the results. Although the conduct and analysis of epidemiological studies has become increasing sophisticated over time, there are a limited number of basic designs, each with their own advantages and disadvantages. This chapter will provide an overview of study design, illustrated with examples from psychiatric epidemiological studies, while individual types of study will be discussed in greater depth in subsequent chapters.

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The costs of an epidemiological study

Epidemiological Studies: A Practical Guide ◽

10.1093/med/9780198814726.003.0024 ◽

2018 ◽

pp. 260-270

Author(s):

Alan J. Silman ◽

Gary J. Macfarlane ◽

Tatiana Macfarlane

Keyword(s):

Epidemiological Study ◽

Study Design ◽

Epidemiological Studies ◽

Value For Money ◽

Methodological Choices ◽

Use Of Resources ◽

Reasonable Cost ◽

Large Populations ◽

Is Value

Epidemiological studies can be very expensive, especially from large populations with multicentre recruitment. The researcher will need to ensure that there are adequate resources, allowing for the fact that things will not always go to plan, but making sure that the research is value for money. What is considered a reasonable cost will also depend on how strong the rationale is for conducting the study. Although in theory the study design influences the costs, in practice the resources available will often constrain the methodological choices. Costing an epidemiological study accurately at the start is vital. There are several ways to maximize the use of resources to ensure the study is efficient.

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