Epidemiology

2017 ◽  
Author(s):  
Sadie Costello ◽  
Jennifer M. Cavallari ◽  
David H. Wegman ◽  
Marie S. O’Neill ◽  
Ellen A. Eisen
Keyword(s):  
Case Control ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Information Selection ◽  
Basic Principles ◽  
Potential Source ◽  
The Common ◽  
Key Aspects ◽  
Study Designs

This chapter describes the basic principles of epidemiology, emphasizing the aspects most relevant to studies of health effects from occupational and environmental exposures. Numerous examples are provided of how epidemiology can be used to identify and quantify the relations between recent or long-term exposure and health outcomes, such as prevalence or incidence of disease, injury, or mortality. The chapter describes the common study designs, including cohort studies, case-control studies, and cross-sectional studies, with examples of their application. Key aspects of exposure assessment and characterizing and quantifying exposure, are described. The three types of bias in epidemiology, information, selection, and confounding, are defined as well as the healthy worker effect, a potential source of bias unique in occupational studies. Study designs and analytic methods that can reduce or eliminate specific types of bias are also described. Finally, the chapter provides guidance on how to interpret the results of studies, with an eye toward causal inference.

Study designs which can demonstrate and test causation

2017 ◽  
Author(s):  
Mark Elwood
Keyword(s):  
Cohort Studies ◽  
Case Control ◽  
Control Group ◽  
Case Control Studies ◽  
Retrospective Case ◽  
Community Based ◽  
Cross Sectional ◽  
Healthcare Interventions ◽  
Intervention Trials ◽  
Study Designs

This chapter presents study designs which can test and show causation. Cohort and intervention studies compare people exposed to an agent or intervention with those unexposed or less exposed. Case-control studies compare people affected by a disease or outcome with a control group of unaffected people or representing a total population. Surveys select a sample of people, not chosen by exposure or outcome. Cohort studies may be prospective or retrospective; case-control studies are retrospective; surveys are cross-sectional in time, but retrospective or prospective aspects can be added. In part two, strengths, weaknesses and applications of these designs are shown. Intervention trials, ideally randomised, are the prime method of assessing healthcare interventions; special types include crossover trials and community-based trials. Non-randomised trials are noted. The strengths and weaknesses of cohort studies, case-control studies, and surveys are shown.

Introduction to epidemiological study designs

2020 ◽  
pp. 83-98
Author(s):  
Tamsin Ford ◽  
Jayati Das-Munshi ◽  
Martin Prince
Keyword(s):  
Mixed Methods ◽  
Data Collection ◽  
Cohort Studies ◽  
Epidemiological Study ◽  
Study Design ◽  
Case Control ◽  
Psychiatric Epidemiology ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Study Designs

This chapter provides a brief overview for each of the main types of study design commonly used in psychiatric epidemiology. The chapter begins with a discussion of the importance of study design. This is followed by a section on classifying study design, including descriptive studies, ecological studies, cross-sectional surveys, cohort studies, case–control studies, intervention studies, and qualitative and mixed methods studies. The chapter concludes with a description of the basic steps which should be observed in the conduct of studies employing quantitative methodologies (including cross-sectional, cohort, and case–control studies), as well as discussing interviews/assessments, and data collection and processing.

scholarly journals The Effect of Prophylactic HPV Vaccines on Oral and Oropharyngeal HPV Infection—A Systematic Review

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1339
Author(s):  
Kristoffer Juul Nielsen ◽  
Kathrine Kronberg Jakobsen ◽  
Jakob Schmidt Jensen ◽  
Christian Grønhøj ◽  
Christian Von Buchwald
Keyword(s):  
Cohort Study ◽  
Oropharyngeal Cancer ◽  
Hpv Infection ◽  
Case Control ◽  
Igg Antibodies ◽  
Hpv Vaccines ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Post Vaccination ◽  
Cross Sectional Studies

Human papillomavirus (HPV) imposes an increased risk of developing cervical, anal and oropharyngeal cancer. In the Western world, HPV infection is currently the major cause of oropharyngeal cancer. The effectiveness of HPV vaccines for oral or oropharyngeal HPV infection is yet to be determined. This study conducted a systematic literature search in Pubmed and Embase. Studies investigating the impact of HPV vaccines on oral or oropharyngeal HPV infection were enrolled. This review reports the relative prevention percentage (RPP), including a risk of bias assessment as well as a quality assessment study. Nine studies were included (48,777 participants): five cross-sectional studies; one randomized community trial study (RCT); one longitudinal cohort study; and two case-control studies. A significant mean RPP of 83.9% (66.6–97.8%) was calculated from the cross-sectional studies, 82.4% in the included RCT and 83% in the longitudinal cohort study. Further, two case-control studies that measured antibody response in participants immunized with HPV vaccines were included. Respectively, 100% and 93.2% of participants developed HPV-16 Immunoglobulin G (IgG) antibodies in oral fluids post-vaccination. Analysis of the studies identified a significant decrease in vaccine-type oral or oropharyngeal HPV infections in study participants immunized with HPV vaccines across study designs and heterogenous populations. Further, a significant percentage of participants developed IgG antibodies in oral fluid post-vaccination.

scholarly journals A probability model for evaluating the bias and precision of influenza vaccine effectiveness estimates from case-control studies

2014 ◽  
Vol 143 (7) ◽  
pp. 1417-1426 ◽  
Author(s):  
M. HABER ◽  
Q. AN ◽  
I. M. FOPPA ◽  
D. K. SHAY ◽  
J. M. FERDINANDS ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Medical Care ◽  
Randomized Clinical Trials ◽  
Probability Model ◽  
Control Design ◽  
Case Control ◽  
Vaccine Effectiveness ◽  
Case Control Studies ◽  
Respiratory Illnesses ◽  
Study Designs

SUMMARYAs influenza vaccination is now widely recommended, randomized clinical trials are no longer ethical in many populations. Therefore, observational studies on patients seeking medical care for acute respiratory illnesses (ARIs) are a popular option for estimating influenza vaccine effectiveness (VE). We developed a probability model for evaluating and comparing bias and precision of estimates of VE against symptomatic influenza from two commonly used case-control study designs: the test-negative design and the traditional case-control design. We show that when vaccination does not affect the probability of developing non-influenza ARI then VE estimates from test-negative design studies are unbiased even if vaccinees and non-vaccinees have different probabilities of seeking medical care against ARI, as long as the ratio of these probabilities is the same for illnesses resulting from influenza and non-influenza infections. Our numerical results suggest that in general, estimates from the test-negative design have smaller bias compared to estimates from the traditional case-control design as long as the probability of non-influenza ARI is similar among vaccinated and unvaccinated individuals. We did not find consistent differences between the standard errors of the estimates from the two study designs.

scholarly journals Subcortical ischemic vascular disease and cognition: A systematic review

2008 ◽  
Vol 2 (2) ◽  
pp. 82-90 ◽  
Author(s):  
Gilberto Sousa Alves ◽  
Carlos Eduardo de Oliveira Alves ◽  
Maria Elisa Lanna ◽  
Denise Madeira Moreira ◽  
Eliasz Engelhardt ◽  
...  
Keyword(s):  
Vascular Disease ◽  
Memory Retrieval ◽  
White Matter Lesions ◽  
Case Control ◽  
Cognitive Status ◽  
Independent Factor ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Cognitive Domains ◽  
The Relationship

Abstract Subcortical Ischemic Vascular Disease (SIVD) is underdiagnosed. This review investigates the relationship among SIVD severity, cognitive status and neuroimaging markers. Methods: Cohort, cross-sectional and case control studies were searched on ISI, Medline, Scielo, PsychoInfo and LILACS databases published between 1995 and 2006. Results: The most impaired cognitive domains were executive, attentional and memory retrieval mechanisms. These cognitive features were frequently associated to White Matter Lesions (WML). Conclusions: WML is an independent factor in cognitive decline. However, the threshold for this impact is not yet clearly established.

scholarly journals Limited Knowledge and Unsafe Practices in Usage of Pesticides and The Associated Toxicity Symptoms among Farmers in Tullo and Finchawa Rural Kebeles, Hawassa City, Sidama Regional State, Southern Ethiopia

2021 ◽  
Author(s):  
Lana MHD Jamal Alshalati
Keyword(s):  
High Risk ◽  
Mixed Methods Research ◽  
Working Hours ◽  
Southern Ethiopia ◽  
Cross Sectional ◽  
Health Related ◽  
Risk Of Exposure ◽  
The Common ◽  
Insufficient Knowledge

The insufficient knowledge regarding safe and proper pesticide handling by farmers in developing countries has led to extensive agricultural expansions at the expense of the health of farmers. The objective of this study was to assess the knowledge and field practices of farmers regarding pesticide handling, and to determine the prevalence of acute and chronic health-related problems in Finchawa and Tullo rural Kebeles of Hawassa City Administration. A cross-sectional mixed methods research design was employed to capture the fuller image of the issue. Farmers’ knowledge regarding pesticide handling and toxicity found to be on average. The odds of the knowledge concerning proper pesticide handling was positively influenced by the factor of age, access to training; and years of experience; Field practices adopted by farmers were disappointing and intentional suicide incidents among teenagers were the result of farmers’ unsafe storage. Nearly all the farmers did not use any means of PPE, and the lack of awareness about the dermal route presented a high risk of exposure. The common self-reported toxicity symptoms experienced by the participants included a headache (84.93%) and slow heartbeats (72.60%). The odds of prevalence of long-term toxicity symptoms found to be negatively correlated with the training factor while the same was positively influenced by the working hours in the farm. The study revealed that there is a high risk of exposure among farmers and their families in the study area.

scholarly journals Post-COVID-19 Syndrome: The Persistent Symptoms at the Post-viral Stage of the Disease. A Systematic Review of the Current Data

2021 ◽  
Vol 8 ◽  
Author(s):  
Francesca Salamanna ◽  
Francesca Veronesi ◽  
Lucia Martini ◽  
Maria Paola Landini ◽  
Milena Fini
Keyword(s):  
Systematic Review ◽  
Chronic Fatigue ◽  
Current Data ◽  
Assessment Tools ◽  
Current Evidence ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Persistent Symptoms ◽  
Collection Form

Whilst the entire world is battling the second wave of COVID-19, a substantial proportion of patients who have suffered from the condition in the past months are reporting symptoms that last for months after recovery, i. e., long-term COVID-19 symptoms. We aimed to assess the current evidence on the long-term symptoms in COVID-19 patients. We did a systematic review on PubMed, Web of Science, EMBASE, and Google Scholar from database inception to February 15, 2021, for studies on long-term COVID-19 symptoms. We included all type of papers that reported at least one long-term COVID-19 symptom. We screened studies using a standardized data collection form and pooled data from published studies. Cohort cross-sectional, case-report, cases-series, case-control studies, and review were graded using specific quality assessment tools. Of 11,361 publications found following our initial search we assessed 218 full-text articles, of which 145 met all selection criteria. We found that 20.70% of reports on long-term COVID-19 symptoms were on abnormal lung functions, 24.13% on neurologic complaints and olfactory dysfunctions, and 55.17% on specific widespread symptoms, mainly chronic fatigue, and pain. Despite the relatively high heterogeneity of the reviewed studies, our findings highlighted that a noteworthy proportion of patients who have suffered from SARS-CoV-2 infection present a “post-COVID syndrome.” The multifaceted understanding of all aspects of the COVID-19 pandemic, including these long-term symptoms, will allow us to respond to all the global health challenges, thus paving the way to a stronger public health.

scholarly journals The effective interventions to improve long-term physiotherapy exercise adherence among patients with lower limb osteoarthritis. A systematic review

2021 ◽  
Author(s):  
Pathmanathan Cinthuja ◽  
Nidhya Krishnamoorthy ◽  
Gamalendira Shivapatham
Keyword(s):  
Systematic Review ◽  
Lower Limb ◽  
English Language ◽  
Data Extraction ◽  
Exercise Adherence ◽  
Case Control Studies ◽  
Eligibility Criteria ◽  
Cross Sectional ◽  
Booster Sessions

Abstract Introduction: Osteoarthritis (OA) is a chronic condition that severely effects work life balance impacting psychosocial and socio-economic aspects. Physiotherapy exercise is one of the intervention methods for the management of OA. Adherence to the exercise by patients is essential for the effective management of OA. Objectives: To determine different methods used to enhance physiotherapy exercise adherence for more than 12 months among patients with osteoarthritis and to report the effective method to enhance exercise adherence among people with lower limb osteoarthritis. Design: Systematic review Methods: PubMed, Pedro, Web of Science, and EMBASE databases searched for randomized controlled trials, cohort studies, case-control studies, and cross-sectional studies published in the English language from 2000 to 2020. The date of data extraction was 04 September 2020. Two independent researchers conducted literature search, assessed eligibility, extracted data, conducted methodology quality assessment using the PEDro scale, and conducted risk of bias assessment. A narrative synthesis of key outcomes is presented; preferred Reporting Items for Systematic review was used to report the review. The study protocol was registered in the Prospero (Prospero ID: CRD42020205653). Results: The primary search strategy identified 5839 potentially relevant articles, of which 5157 remained after discarding duplicates. After screening based on title and abstract, 40 papers were potentially eligible for inclusion. Five of these papers met all predefined eligibility criteria. Introducing methods to enhance exercise adherence has caused a significant increase in exercise adherence for the short term (less than six months or 12 months). There were no significant differences, long-term adherence with different methods, reported. The results indicate that booster sessions (89.69%) and telephone-linked communication (86%) had higher percentages for the exercise adherence. Secondary outcomes such as pain, stiffness, function, show positive outcomes with increasing exercise adherence. However, there were no significant differences reported. Conclusion: The booster sessions and telephone-linked communication appear to enhance exercise adherence for more than 12 months among patients with osteoarthritis. However, a number of high-quality studies are inadequate to confirm our findings. Therefore, more studies with higher methodological quality are needed to determine the best strategies to enhance long-term exercise adherence among people with osteoarthritis. Key terms: Osteoarthritis, Long term, Exercise adherence

scholarly journals Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): Explanation and Elaboration. Translation to Russian

2021 ◽  
pp. 1-10
Author(s):  
Jan P. Vandenbroucke ◽  
Erik Von Elm ◽  
Douglas G. Altman ◽  
Peter C. Gotzsche ◽  
Cynthia D. Mulrow ◽  
...  
Keyword(s):  
Observational Studies ◽  
Empirical Studies ◽  
Observational Research ◽  
Case Control Studies ◽  
Quality Of Reporting ◽  
Cross Sectional ◽  
Useful Flow ◽  
Study Designs ◽  
Strobe Statement

Much medical research is observational. The reporting of observational studies is often of insufficient quality. Poor reporting hampers the assessment of the strengths and weaknesses of a study and the generalisability of its results. Taking into account empirical evidence and theoretical considerations, a group of methodologists, researchers, and editors developed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) recommendations to improve the quality of reporting of observational studies. The STROBE Statement consists of a checklist of 22 items, which relate to the title, abstract, introduction, methods, results and discussion sections of articles. Eighteen items are common to cohort studies, case-control studies and cross-sectional studies and four are specific to each of the three study designs. The STROBE Statement provides guidance to authors about how to improve the reporting of observational studies and facilitates critical appraisal and interpretation of studies by reviewers, journal editors and readers. This explanatory and elaboration document is intended to enhance the use, understanding, and dissemination of the STROBE Statement. The meaning and rationale for each checklist item are presented. For each item, one or several published examples and, where possible, references to relevant empirical studies and methodological literature are provided. Examples of useful flow diagrams are also included. The STROBE Statement, this document, and the associated Web site (http://www. strobe-statement.org/) should be helpful resources to improve reporting of observational research. This article is the reprint with Russian translation of the original that can be observed here: Vandenbroucke JP, von Elm E, Altman DG, Gotzsche PC, Mulrow CD, et al. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): Explanation and Elaboration. PLoS Med 2007;4(10):e297. doi:10.1371/journal.pmed.0040297

scholarly journals Epidemiological evidence relating environmental smoke to COPD in lifelong non-smokers: a systematic review

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 146 ◽  
Author(s):  
Peter N. Lee ◽  
Barbara A. Forey ◽  
Katharine J. Coombs ◽  
Jan S. Hamling ◽  
Alison J. Thornton
Keyword(s):  
Meta Analysis ◽  
Middle Eastern ◽  
Epidemiological Data ◽  
Case Control ◽  
Chronic Obstructive ◽  
Exposure Index ◽  
Bias Estimation ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Main Index

Background: Some evidence suggests environmental tobacco smoke (ETS) might cause chronic obstructive pulmonary disease (COPD). We reviewed available epidemiological data in never smokers. Methods: We identified epidemiological studies providing estimates of relative risk (RR) with 95% confidence interval (CI) for various ETS exposure indices. Confounder-adjusted RRs for COPD were extracted, or derived using standard methods. Meta-analyses were conducted for each exposure index, with tests for heterogeneity and publication bias. For the main index (spouse ever smoked or nearest equivalent), analyses investigated variation in RR by location, publication period, study type, sex, diagnosis, study size, confounder adjustment, never smoker definition, and exposure index definition. Results: Twenty-eight relevant studies were identified; nine European or Middle Eastern, nine Asian, eight American and two from multiple countries. Five were prospective, seven case-control and 16 cross-sectional. The COPD definition involved death or hospitalisation in seven studies, GOLD stage 1+ criteria in twelve, and other definitions in nine. For the main index, random-effects meta-analysis of 33 heterogeneous (p<0.001) estimates gave a RR of 1.20 (95%CI 1.08-1.34). Higher estimates for females (1.59,1.16-2.19, n=11) than males (1.29,0.94-1.76, n=7) or sexes combined (1.10,0.99-1.22, n=15 where sex-specific not available), and lower estimates for studies of 150+ cases (1.08,0.97-1.20, n=13) partly explained the heterogeneity. Estimates were higher for Asian studies (1.34,1.08-1.67, n=10), case-control studies (1.55,1.04-2.32, n=8), and COPD mortality or hospitalisation (1.40,1.12-1.74, n=11). Some increase was seen for severer COPD (1.29,1.10-1.52, n=7). Dose-response evidence was heterogeneous. Evidence for childhood (0.88,0.72-1.07, n=2) and workplace (1.12,0.77-1.64, n=4) exposure was limited, but an increase was seen for overall adulthood exposure (1.20,1.03-1.39, n=17). We discuss study weaknesses that may bias estimation of the association of COPD with ETS. Conclusions: Although the evidence suggests ETS increases COPD, study weaknesses and absence of well-designed large studies precludes reliable inference of causality. More definitive evidence is required.

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