scholarly journals A novel framework for classification of selection processes in epidemiological research

2020 ◽  
Author(s):  
Jonas Bjork ◽  
Anton Nilsson ◽  
Carl Bonander ◽  
Ulf Strömberg

Abstract Background: Selection and selection bias are terms that lack consistent definitions and have varying meaning and usage across disciplines. There is also confusion in current definitions between underlying mechanisms that lead to selection and their consequences. Consequences of selection on study validity must be judged on a case-by-case basis depending on research question, study design and analytical decisions. The overall aim of the study was to develop a simple but general framework for classifying various types of selection processes of relevance for epidemiological research. Methods: Several original articles from the epidemiological literature and from related areas of observational research were reviewed in search of examples of selection processes, used terminology and description of the underlying mechanisms. Results: We classified the identified selection processes in three dimensions: i) selection level (selection at the population level vs. study-specific selection), ii) type of mechanism (selection in exposure vs. selection in population composition), iii) timing of the selection (at exposure entry, during exposure/follow-up or post-outcome). Conclusions: Increased understanding of when, how, and why selection occur is an important step towards improved validity of epidemiological research.

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jonas Björk ◽  
Anton Nilsson ◽  
Carl Bonander ◽  
Ulf Strömberg

Abstract Background Selection and selection bias are terms that lack consistent definitions and have varying meaning and usage across disciplines. There is also confusion in current definitions between underlying mechanisms that lead to selection and their consequences. Consequences of selection on study validity must be judged on a case-by-case basis depending on research question, study design and analytical decisions. The overall aim of the study was to develop a simple but general framework for classifying various types of selection processes of relevance for epidemiological research. Methods Several original articles from the epidemiological literature and from related areas of observational research were reviewed in search of examples of selection processes, used terminology and description of the underlying mechanisms. Results We classified the identified selection processes in three dimensions: i) selection level (selection at the population level vs. study-specific selection), ii) type of mechanism (selection in exposure vs. selection in population composition), iii) timing of the selection (at exposure entry, during exposure/follow-up or post-outcome). Conclusions Increased understanding of when, how, and why selection occur is an important step towards improved validity of epidemiological research.


2020 ◽  
Author(s):  
Jonas Bjork ◽  
Anton Nilsson ◽  
Carl Bonander ◽  
Ulf Strömberg

Abstract Background: Selection and selection bias are terms that lack consistent definitions and have varying meaning and usage across disciplines. There is also confusion in current definitions between underlying mechanisms that lead to selection and their consequences. Consequences of selection on study validity must be judged on a case-by-case basis depending on research question, study design and analytical decisions. The overall aim of the study was to develop a simple but general framework for classifying various types of selection processes of relevance for epidemiological research. Methods: Several original articles from the epidemiological literature and from related areas of observational research were reviewed in search of examples of selection processes, used terminology and description of the underlying mechanisms. Results: We classified the identified selection processes in three dimensions: i) selection level (selection at the population level vs. study-specific selection), ii) type of mechanism (selection in exposure vs. selection in population composition), iii) timing of the selection (at exposure entry, during exposure or post-outcome). Conclusions: Increased understanding of when, how, and why selection occur is an important step towards improved validity of epidemiological research.


2019 ◽  
Author(s):  
Jonas Bjork ◽  
Anton Nilsson ◽  
Carl Bonander ◽  
Ulf Strömberg

Abstract Background: Non-participation, losses to follow up and other types of study-specific selection mechanisms can be serious concerns in epidemiological studies. There are also selection processes that result in non-random groupings and changes in the composition of populations. These are continuously on-going irrespectively of whether they are subject to sampling in empirical studies. Such population selections are often overlooked, but may lead to lack of comparability of exposed and unexposed populations or decrease study validity in other ways. The overall aim of this study was to develop a simple but general framework for classifying various types of selection mechanisms of relevance for epidemiological research. Methods: We classify selection mechanisms in three dimensions: i) selection at the population level vs. selection that is study-specific, ii) type of mechanism (selection causing exposure vs. selection in population at risk), iii) timing of the selection (pre-exposure, during exposure or post-outcome). Results: Examples from the epidemiological literature of selection mechanisms are discussed and classified according to the three dimensions of the proposed framework. Conclusions: Increased mechanistic understanding of when, how, and why confusion of effects can occur because of selection is an important step towards improved validity of epidemiological research.


Author(s):  
Carolin Szász-Janocha ◽  
Eva Vonderlin ◽  
Katajun Lindenberg

Zusammenfassung. Fragestellung: Das junge Störungsbild der Computerspiel- und Internetabhängigkeit hat in den vergangenen Jahren in der Forschung zunehmend an Aufmerksamkeit gewonnen. Durch die Aufnahme der „Gaming Disorder“ in die ICD-11 (International Statistical Classification of Diseases and Related Health Problems) wurde die Notwendigkeit von evidenzbasierten und wirksamen Interventionen avanciert. PROTECT+ ist ein kognitiv-verhaltenstherapeutisches Gruppentherapieprogramm für Jugendliche mit Symptomen der Computerspiel- und Internetabhängigkeit. Die vorliegende Studie zielt auf die Evaluation der mittelfristigen Effekte nach 4 Monaten ab. Methodik: N = 54 Patientinnen und Patienten im Alter von 9 bis 19 Jahren (M = 13.48; SD = 1.72) nahmen an der Frühinterventionsstudie zwischen April 2016 und Dezember 2017 in Heidelberg teil. Die Symptomschwere wurde zu Beginn, zum Abschluss der Gruppentherapie sowie nach 4 Monaten anhand von standardisierten Diagnostikinstrumenten erfasst. Ergebnisse: Mehrebenenanalysen zeigten eine signifikante Reduktion der Symptomschwere anhand der Computerspielabhängigkeitsskala (CSAS) nach 4 Monaten. Im Selbstbeurteilungsbogen zeigte sich ein kleiner Effekt (d = 0.35), im Elternurteil ein mittlerer Effekt (d = 0.77). Der Reliable Change Index, der anhand der Compulsive Internet Use Scale (CIUS) berechnet wurde, deutete auf eine starke Heterogenität im individuellen Symptomverlauf hin. Die Patientinnen und Patienten bewerteten das Programm zu beiden Follow-Up-Messzeitpunkten mit einer hohen Zufriedenheit. Schlussfolgerungen: Die vorliegende Arbeit stellt international eine der wenigen Studien dar, die eine Reduktion der Symptome von Computerspiel- und Internetabhängigkeit im Jugendalter über 4 Monate belegen konnte.


BMJ Open ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. e043010
Author(s):  
Jane Lyons ◽  
Ashley Akbari ◽  
Fatemeh Torabi ◽  
Gareth I Davies ◽  
Laura North ◽  
...  

IntroductionThe emergence of the novel respiratory SARS-CoV-2 and subsequent COVID-19 pandemic have required rapid assimilation of population-level data to understand and control the spread of infection in the general and vulnerable populations. Rapid analyses are needed to inform policy development and target interventions to at-risk groups to prevent serious health outcomes. We aim to provide an accessible research platform to determine demographic, socioeconomic and clinical risk factors for infection, morbidity and mortality of COVID-19, to measure the impact of COVID-19 on healthcare utilisation and long-term health, and to enable the evaluation of natural experiments of policy interventions.Methods and analysisTwo privacy-protecting population-level cohorts have been created and derived from multisourced demographic and healthcare data. The C20 cohort consists of 3.2 million people in Wales on the 1 January 2020 with follow-up until 31 May 2020. The complete cohort dataset will be updated monthly with some individual datasets available daily. The C16 cohort consists of 3 million people in Wales on the 1 January 2016 with follow-up to 31 December 2019. C16 is designed as a counterfactual cohort to provide contextual comparative population data on disease, health service utilisation and mortality. Study outcomes will: (a) characterise the epidemiology of COVID-19, (b) assess socioeconomic and demographic influences on infection and outcomes, (c) measure the impact of COVID-19 on short -term and longer-term population outcomes and (d) undertake studies on the transmission and spatial spread of infection.Ethics and disseminationThe Secure Anonymised Information Linkage-independent Information Governance Review Panel has approved this study. The study findings will be presented to policy groups, public meetings, national and international conferences, and published in peer-reviewed journals.


2021 ◽  
pp. 1-10
Author(s):  
Melody R. Altschuler ◽  
Robert F. Krueger

Abstract Traditional categorical approaches to classifying personality disorders are limited in important ways, leading to a shift in the field to dimensional approaches to conceptualizing personality pathology. Different areas of psychology – personality, developmental, and psychopathology – can be leveraged to understand personality pathology by examining its structure, development, and underlying mechanisms. However, an integrative model that encompasses these distinct lines of inquiry has not yet been proposed. In order to address this gap, we review the latest evidence for dimensional classification of personality disorders based on structural models of maladaptive personality traits, provide an overview of developmental theories of pathological personality, and summarize the Research Domain Criteria (RDoC) initiative, which seeks to understand underlying mechanisms of psychopathology. We conclude by proposing an integrative model of personality pathology development that aims to elucidate the developmental pathways of personality pathology and its underlying mechanisms.


BMJ Open ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. e040959
Author(s):  
Saman Khalatbari-Soltani ◽  
Pedro Marques-Vidal ◽  
Fumiaki Imamura ◽  
Nita G. Forouhi

ObjectiveThe Mediterranean diet has been promoted as a healthy dietary pattern, but whether the Mediterranean diet may help to prevent hepatic steatosis is not clear. This study aimed to evaluate the prospective association between adherence to the Mediterranean diet and risk of hepatic steatosis.DesignPopulation-based prospective cohort study.SettingThe Swiss CoLaus Study.ParticipantsWe evaluated 2288 adults (65.4% women, aged 55.8±10.0 years) without hepatic steatosis at first follow-up in 2009–2012. Adherence to the Mediterranean diet was scaled as the Mediterranean diet score (MDS) based on the Mediterranean diet pyramid ascertained with responses to Food Frequency Questionnaires.Outcome measuresNew onset of hepatic steatosis was ascertained by two indices separately: the Fatty Liver Index (FLI, ≥60 points) and the non-alcoholic fatty liver disease (NAFLD) score (≥−0.640 points). Prospective associations between adherence to the Mediterranean diet and risk of hepatic steatosis were quantified using Poisson regression.ResultsDuring a mean 5.3 years of follow-up, hepatic steatosis was ascertained in 153 (6.7%) participants by FLI criteria and in 208 (9.1%) by NAFLD score. After multivariable adjustment, higher adherence to MDS was associated with lower risk of hepatic steatosis based on FLI: risk ratio 0.84 (95% CI 0.73 to 0.96) per 1 SD of MDS; 0.85 (0.73 to 0.99) adjusted for BMI; and 0.85 (0.71 to 1.02) adjusted for both BMI and waist circumference. When using NAFLD score, no significant association was found between MDS and risk of hepatic steatosis (0.95 (0.83 to 1.09)).ConclusionA potential role of the Mediterranean diet in the prevention of hepatic steatosis is suggested by the inverse association observed between adherence to the Mediterranean diet and incidence of hepatic steatosis based on the FLI. The inconsistency of this association when hepatic steatosis was assessed by NAFLD score points to the need for accurate population-level assessment of fatty liver and its physiological markers.


Author(s):  
Katriina Heikkilä ◽  
Ellenor Mittendorfer-Rutz ◽  
Kristina Alexanderson ◽  
Marianna Virtanen

Observational research studies from various countries suggest that women’s working patterns across the life course are often fragmented compared to men’s. The aim of our investigation was to use nationwide register data from Sweden to examine the extent to which generation and time of entry to the work force explain the sex differences in work participation across the life course. Our analyses were based on individual-level data on 4,182,581 women and 4,279,571 men, who were 19–69 years old and resident in Sweden in 1995, 2000, 2005, 2010, or 2015. Data on income and number of net days on disability pension, obtained from multiple linked registers, were used to ascertain each individual’s main activity (in paid work, on disability pension, and not in paid work) each year. Years in paid work and on disability pension were calculated as the sums of years spent in either of these states from age 19 to 69 years. We used negative binomial regression to model the associations of generation and baseline year with years in paid work and years on disability pension. All models were run separately for women and men, with the duration of follow-up constrained to one, to account for the different follow-up times between individuals. Overall, the number of years in paid work across the life course was larger among men than women, and men entered into the workforce earlier. The difference between women and men was similar across generations and time periods. Adjustment for education, income, number of children aged <18 years living at home, country of birth, and the type of residential area had minimal impact on the estimates. Our findings suggest that women spend fewer years in paid work across the life course than men, highlighting the need for continued efforts to close the gender gap in work participation.


2000 ◽  
Vol 9 (3) ◽  
pp. 171-189 ◽  
Author(s):  
Mark Woodward ◽  
Jean Nursten ◽  
Paul Williams ◽  
Doug Badger

SummaryObjective – This paper reviews 28 studies on the epidemiology of homicide committed by mentally disordered people, taken from recent international academic literature. Methods – The studies included were identified as part of a wider systematic review of the epidemiology of offending combined with mental disorder. The main databases searched were Embase, Medline, HealthStar, Psyclit, Mental Health Abstracts, Applied Social Sciences Index and Abstracts, and Criminology Penology and Police Science Abstracts. A comprehensive search was made for studies published since 1990, supplemented with key studies from the 1980s identified through citation tracing and personal contacts. Results – A summary is given in tabular form of the content and quality of each study. There is then discussion of the studies in eight categories: descriptive studies, studies of trends, comparative studies amongst homicide offenders, amongst prisoners and including general populations, studies of homicide of relatives, follow-up studies, and studies of recidivism. Conclusions – There is an association of homicide with mental disorder, most particularly with certain manifestations of schizophrenia, antisocial personality disorder and drug or alcohol abuse. However, the quality of epidemiological research in this area is not adequate to answer key questions, and prediction of potential for homicide remains elusive. Further research is needed.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Dorota Reis ◽  
Alexander Hart ◽  
Dirk Lehr ◽  
Malte Friese

Abstract Background Work-related stress shows steadily increasing prevalence rates and has tangible consequences for individual workers, their organizations, and society as a whole. One mechanism that may help offset the negative outcomes of work-related stress on employees’ well-being is recovery. Recovery refers to the experience of unwinding from one's job when not at work. However, employees who experience high levels of work-related stress and are thus particularly in need of recovery tend to struggle to switch-off. Due to the detrimental effects of this prolonged and sustained mental representation of job stressors, interventions promoting recovery may contribute to improvements in employees' mental health. Methods In this randomized, waitlist controlled trial, we will investigate the effectiveness of two 6-week online training programs (cognitive behavioral and mindfulness-based). The sample will include employees working at least part-time during regular work hours. Besides the pre-post-follow-up assessments, the trial will include measurement bursts with the goal of examining the underlying mechanisms. We expect that both interventions will reduce work-related perseverative thinking (PT) compared with the waitlist control groups (primary outcome). Also, we expect that both interventions will result in similar improvements, but the underlying mechanisms will differ (process outcomes). In the cognitive-behavioral intervention group, we expect that the main mechanism responsible for lower PT levels will be an increase in recovery experiences across time. In the mindfulness-based group, we expect that the main mechanism responsible for lower PT levels will be an increase in facets of mindfulness across time. Discussion In the present study, we will investigate mechanisms underlying assumed changes in work-related PT in great detail. Besides evaluating the overall effectiveness of the two interventions in terms of pre-post-follow-up changes, we will look at the underlying processes at different levels—that is, within days, within weeks, across weeks, and between individuals. Accordingly, our study will offer a fine-grained approach to investigating potential determinants, mediators, and moderators of the processes that may, in the end, be responsible for work-related strain. From a public health perspective, if effective, the online training programs may offer valuable, low-threshold, and low-intensity interventions for a broad range of occupations. Trial registration German Clinical Trials Registration: DRKS00024933. Registered prospectively 7 April 2021. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00024933


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