George TH Ellison

George TH Ellison
University of Central Lancashire | UCLAN · School of Computing, Engineering and Physical Sciences

Professor
Public Policy; Service Evaluation; Data Innovation; Evidence-informed Policy; Health and Healthcare

About

212
Publications
29,533
Reads
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3,813
Citations
Citations since 2016
55 Research Items
1918 Citations
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Introduction
Professor of Data Science and Director of the Centre for Data Innovation at the University of Central Lancashire. Formerly: Deputy Director (Education & Training) - Leeds Institute for Data Analytics (https://lida.leeds.ac.uk/). Currently: Visiting Professor of Epidemiology at Leeds Medical School (https://medicinehealth.leeds.ac.uk/medicine). ORCID:​ ​0000-0001-8914-6812 (https://orcid.org/0000-0001-8914-6812)

Publications

Publications (212)
Article
Full-text available
In South Africa, demand for housing close to viable/sustained sources of employment has far outstripped supply; and the size of the population living in temporary structures/shacks (and in poorly serviced informal settlements) has continued to increase. While such dwellings and settlements pose a number of established risks to the health of their r...
Article
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Policies that aim to facilitate and promote non-motorised transport (NMT), and in particular cycling, have been developed by many high-income countries facing increasingly congested roads and saturated public transport systems. Such policies are also emerging in many low- and middle-income settings where high rates of urbanisation have led to simil...
Article
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The failure to reduce maternal mortality rates in high-burden countries has led to calls for a greater understanding of structural determinants of inequities in access to maternal health services. Caste is a socially constructed identity that imposes structural disadvantages on subordinate groups. Although a South Asian construct, the existence of...
Article
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Background In longitudinal data, it is common to create ‘change scores’ by subtracting measurements taken at baseline from those taken at follow-up, and then to analyse the resulting ‘change’ as the outcome variable. In observational data, this approach can produce misleading causal-effect estimates. The present article uses directed acyclic graphs...
Article
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Temporality-driven covariate classification had limited impact on: the specification of directed acyclic graphs (DAGs) by 85 novice analysts (medical undergraduates); or the risk of bias in DAG-informed multivariable models designed to generate causal inference from observational data. Only 71 students (83.5%) managed to complete the ‘Temporality-d...
Article
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The present study aimed to compare the predictive acuity of latent class regression (LCR) modelling with: standard generalised linear modelling (GLM); and GLMs that include the membership of subgroups/classes (identified through prior latent class analysis; LCA) as alternative or additional candidate predictors. Using real world demographic and cli...
Article
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Background Directed acyclic graphs (DAGs) are an increasingly popular approach for identifying confounding variables that require conditioning when estimating causal effects. This review examined the use of DAGs in applied health research to inform recommendations for improving their transparency and utility in future research. Methods Original he...
Preprint
Full-text available
The present study aimed to compare the predictive acuity of latent class regression (LCR) modelling with: standard generalised linear modelling (GLM); and GLMs that include the membership of subgroups/classes (identified through prior latent class analysis; LCA) as alternative or additional candidate predictors. Using real world demographic and cli...
Article
Objective: The present study evaluated an intervention designed to introduce University students as potential users of Johannesburg's cycle lanes. Participants: A total of 393 undergraduate and postgraduate students from the University of Johannesburg took part. Methods: Following cycling and safety training, participants undertook a 1.2 km superv...
Article
Objectives The ‘poor housing, good health’ paradox observed by De Wet et al. (2011) across eight of Johannesburg's poorest Wards (neighbourhoods), was re-examined using: a more generic measure of self-reported health; better-specified adjustment for measured confounders; household data from a range of Wards and income strata across Johannesburg and...
Article
The models used to estimate disease transmission, susceptibility and severity determine what epidemiology can (and cannot tell) us about COVID-19. These include: ‘model organisms’ chosen for their phylogenetic/aetiological similarities; multivariable statistical models to estimate the strength/direction of (potentially causal) relationships between...
Preprint
Full-text available
The models used to estimate disease transmission, susceptibility and severity determine what epidemiology can (and cannot tell) us about COVID-19. These include: ‘model organisms’ chosen for their phylogenetic/aetiological similarities; multivariable statistical models to estimate the strength/direction of (potentially causal) relationships between...
Preprint
Full-text available
Directed acyclic graphs (DAGs) might yet transform the statistical modelling of observational data for causal inference. This is because they offer a principled approach to analytical design that draws on existing contextual, empirical and theoretical knowledge, but ultimately relies on temporality alone to objectively specify probabilistic causal...
Article
Objective: The present study examined potential barriers to cycle-based transport amongst undergraduate students, to inform the design of future cycling promotion interventions at the University of Johannesburg (UJ). Participants: A total of 606 first, second and third year UJ undergraduates took part. Methods: Sociodemographic and economic determi...
Article
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Background: Intervention differential effects (IDEs) occur where changes in an outcome depend upon the initial values of that outcome. Although methods to identify IDEs are well documented, there remains a lack of understanding about the circumstances under which these methods are robust. One context that has not been explored is the identification...
Preprint
Full-text available
BACKGROUND: Directed acyclic graphs (DAGs) are an increasingly popular approach for identifying confounding variables that require adjustment when estimating causal effects. This review examined the use of DAGs in applied health research to inform recommendations for improving their transparency and utility in future research. METHODS: Original hea...
Conference Paper
Background Studies of change are a cornerstone of research in the health sciences. Robust analyses of change are however extremely challenging, especially in observational data.In simple exposure-outcome scenarios, one common approach is to create and analyse an outcome ‘change-score’ by subtracting the baseline outcome from follow-up outcome. Tens...
Conference Paper
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Background The practice of routinely weighing pregnant women to monitor their ‘weight gain’ is controversial. In the United States, the National Academy of Medicine (NAM) advises regular weighing and recommends ‘optimum’ gain targets according to pre-pregnancy body mass index (BMI). In the United Kingdom, the National Institute for Health and Care...
Preprint
Full-text available
Background: In longitudinal data, it is common to create 'change scores' by subtracting measurements taken at baseline from those taken at follow-up, and then to analyse the resulting 'change' as the outcome variable. In observational data, this approach can produce misleading causal effect estimates. The present article uses directed acyclic graph...
Article
Full-text available
While the omission of behavioural and mechanistic factors from the BBC’s “Life Expectancy Calculator” might undermine its utility as a health promotion tool, the centrality of these factors within the GBD 2016 Risk Factor Collaborators’ analyses – which only detected “important changes” in behavioural (tobacco, alcohol and diet) and mechanistic (lo...
Article
Although the studies highlighted in Kinlen and Peto’s letter describe situations they take to be “national in scope”, none of these adopted the ‘region-wide’ analysis we recommend. Rather, these studies have focussed on rural areas with small populations experiencing extreme levels of inward-migration that had been selected from larger regions/nati...
Article
Full-text available
Biological determinism is the tendency to view human social phenomena (at the individual, group, and societal level) as the products of biological causes. It can be traced back to the earliest philosophical ideas regarding the biological basis of human nature, and it has played an important role in the interpretation of scientific advances in human...
Conference Paper
Full-text available
Background Intervention differential effects (IDE) occur when change in a health outcome following an intervention depends upon the baseline value of that outcome. Oldham’s method and multilevel modelling are methods used to detect IDEs. However, the conditions under which these methods are robust are not well documented. One condition that has not...
Conference Paper
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Background Because responses to interventions can be heterogeneous, interest may lie in the extent to which any given individual’s response to an intervention relates to their baseline status (an intervention differential effect; IDE). In interventions designed to prevent excess childhood weight gain, researchers may want to investigate whether chi...
Article
BACKGROUND: Studies investigating the population-mixing hypothesis in childhood leukemia principally use two analytical approaches: (1) nonrandom selection of areas according to specific characteristics, followed by comparisons of their incidence of childhood leukemia with that expected based on the national average; and (2) regression analyses of...
Article
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‘Unexplained residuals’ (UR) models have been used within lifecourse epidemiology to model an exposure measured longitudinally at several time points in relation to a distal outcome. It has been claimed that these models have several advantages, including: the ability to estimate multiple total causal effects in a single model, and additional insig...
Conference Paper
Background Empirical researchers working with observational data have been slow to adopt modern statistical methods for causal inference, which remain poorly recognised among applied quantitative researchers. First introduced in 2010, DAGitty is a free web application (and R package) that enables empirical researchers to draw directed acyclic graph...
Conference Paper
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Advanced Modelling Strategies: Challenges and pitfalls in robust causal inference with observational data summarises the lecture notes prepared for a four-day workshop sponsored by the Society for Social Medicine and hosted by the Leeds Institute for Data Analytics (LIDA) at the University of Leeds on 17th-20th July 2017.
Chapter
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Biological determinism is the tendency to view human social phenomena (at the individual, group and societal level) as the products of biological causes. It can be traced back to the earliest philosophical ideas regarding the biological basis of human nature, and it has played an important role in the interpretation of scientific advances in human...
Article
Directed acyclic graphs (DAGs), which offer systematic representations of causal relationships, have become an established framework for the analysis of causal inference in epidemiology, often being used to determine covariate adjustment sets for minimizing confounding bias. DAGitty is a popular web application for drawing and analysing DAGs. Here...
Conference Paper
Background: The aim of the present study was to establish the desirability of developing a generic search strategy for sleep-related studies based on search strategies used by contemporary systematic reviews of sleep research. Methods: Search I searched Ovid-Medline for the expanded term "sleep*" between "2012 to present" with no language limits ap...
Conference Paper
To assess how pregnancy might influence sleeping patterns. A cross sectional study to compare eight sleep variables (sleep duration; latency; disturbance; and snoring; sleep quality; medication; and daytime sleepiness, sleep worry) amongst pregnant and non-pregnant. Logistic regression was performed to examine sleeping patterns in pregnant and n...
Article
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Background Within lifecourse epidemiology, there is substantial interest in relationships between exposures (X) measured longitudinally (e.g. at time 0, 1, 2; hence X0, X1, X2) and outcomes (Y) measured cross-sectionally once (e.g. Y2 or Y2 + t). Within a causal framework, modelling presents many challenges, such as how to account for time-invarian...
Article
Background Dietary advice plays an important role in the management of gestational diabetes (GDM), yet eating behaviours are susceptible to a range of social and environmental factors capable of undermining the utility of dietary advice. The aim of the present study was to establish the direction and strength of any associations between one such fa...
Article
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Background Sleep varies markedly within and between individuals and, as a multifactorial trait, sleep can be challenging to operationalise. The aim of the present study was to assess whether latent class analysis (LCA) might identify distinct sleeping patterns that not only capture the complexity of sleep but are meaningfully associated with key so...
Article
Background Many epidemiological studies are interested in examining whether change in a variable from its baseline (Y0) to follow-up (Y1; hence ΔY = Y1 − Y0) can be predicted by (and is therefore potentially caused by) a second variable also measured at baseline (X0). Although these analyses appear straightforward, they may incur a statistical arte...
Article
Background (Dis)agreements between self-reports of prior clinical diagnoses and objective assessments of disease status provide potentially important insights into three specific processes: (mis)communication of clinical diagnoses; (un)awareness of disease risk; and (non)modification of disease risk post-diagnosis. This study explored these process...
Article
Background Previous research exploring the link between population mixing and childhood leukaemia has generated equivocal and contradictory results. This research has adopted two principal analytical approaches: (i) selecting areas according to specific characteristics and comparing the incidence of childhood leukaemia in these areas with that expe...
Article
Background Within lifecourse epidemiology, there is substantial interest in relationships between exposures (X) that are measured longitudinally (e.g. at time 0, 1, 2; hence X0, X1, X2) and outcomes (Y) that are measured once, cross-sectionally (e.g. Y2 or Y2+t). Methods used to analyse these relationships often involve conditioning on the outcome...
Article
Background The American Academy of Sleep Medicine include ‘pregnancy-associated sleep disorder’ (PASD) in its International Classification of Sleep Disorders. PASD is indicated by: either frequent arousals and reduced sleep efficiency or a prolonged habitual sleep duration; and habitual sleep latencies of <10 min. The present study aimed to assess...
Article
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Inequitable healthcare access, experiences and outcomes across ethnic groups are of concern across many countries. Progress on this agenda appears limited in England given the apparently strong legal and policy framework. This disjuncture raises questions about how central government policy is translated into local services. Healthcare commissionin...
Conference Paper
Full-text available
P122 Sleep is associated with glycaemic control in women with gestational diabetes (GDM) http://onlinelibrary.wiley.com/doi/10.1111/dme.18_13048/epdf
Article
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Background and aim: The aim of the present study was to assess the relative importance of individual- and household-level indicators of poverty to the self-reported health of residents and recent migrants in South Africa's most urbanised province (Gauteng). Subjects and methods: The survey generated data on a representative sample of n=27,490 re...
Article
Full-text available
Inequitable healthcare access, experiences and outcomes across ethnic groups are of concern across many countries. Progress on this agenda appears limited in England given the apparently strong legal and policy framework. This disjuncture raises questions about how central government policy is translated into local services. Healthcare commissionin...
Article
Oral glucose tolerance test results are affected by prior sleep duration: a randomised control crossover trial of normoglycaemic adults - Volume 75 Issue OCE1 - G.TH. Ellison, E.M. Scott, G.R. Law
Article
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Postpartum weight retention and sleep: a systematic review - Volume 75 Issue OCE1 - L. Alrefaai, G.TH. Ellison, G.R. Law, E.M. Scott
Article
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Variation in sleep is associated with diagnosis of late-onset diabetes: a cross-sectional analysis of self-reported data from the first wave of ‘Understanding Society’ (the UK Household Longitudinal Study) - Volume 75 Issue OCE1 - R.A. Alfawaz, G.R. Law, E.M. Scott, G.TH. Ellison
Article
Relationship between sleep quality, sleep duration and glucose control in pregnant women with gestational diabetes - Volume 75 Issue OCE1 - A. Alnaji, G.TH. Ellison, G.R. Law, E.M. Scott
Article
Full-text available
Short sleep duration is associated with an increased risk of gestational diabetes: Systematic review and meta-analysis - Volume 75 Issue OCE1 - A.A. Alghamdi, N.A. Al Afif, G.R. Law, E.M. Scottand, G.TH. Ellison
Article
Full-text available
While there is substantial evidence that obesity is a risk factor for poor sleep, not least as a result of an increased risk of obstructive sleep apnoea, the possibility that sleep might play a role in energy metabolism and the development of obesity has led to much speculation and a raft of fresh research in this area. Much of the evidence to-date...
Article
Continuous glucose monitoring (CGM) is increasingly used to assess glucose control in diabetes. The objective was to examine how analysis of glucose data might improve our understanding of the role temporal glucose variation has on large-for-gestational-age (LGA) infants born to women with diabetes. Functional data analysis (FDA) was applied to 1.6...
Article
Background In epidemiological surveys, sleep quality is assessed using seven distinct criteria namely: sleep duration; latency; disturbance; coughing/snoring; perceived quality; medication and daytime sleepiness. Due to the complex functional, conceptual and mathematical interrelationships between these seven criteria epidemiologists face substanti...
Article
Background Each year numerous studies evaluate longitudinal data within a lifecourse context with later-life health status (e.g. systolic blood pressure, SBP) analysed with respect to repeated measures of early-life experiences (e.g. body mass index, BMI), using standard multiple linear regression inappropriately. We examine these problems, via sim...
Article
Background Traditional classifications of the metabolic syndrome (MetS) rely on measurements of central obesity and clinical diagnoses of diabetes, hypercholesterolaemia and hypertension – criteria that are rarely available in large-scale epidemiological surveys. The aim of the present analysis was to assess whether questionnaire-derived, self-repo...
Article
Full-text available
Background Strong observational evidence exists, from small- and medium-scale studies, linking short, disturbed and poor quality sleep with metabolic and cardiovascular disorders. However, the extent to which such evidence might be generalisable to the general population remains unclear, and to-date there have been no large-scale nationally represe...
Conference Paper
Full-text available
Directed Acyclic Graphs (DAGs) offer an innovative framework for research design and communication that is gaining in popularity, not least amongst observational epidemiologists where statistical analyses are routinely published with insufficient detail on any underlying causal theories to permit an assessment of whether these analyses include (in)...
Conference Paper
Full-text available
Background: Directed Acyclic Graphs (DAGs) are increasingly popular with researchers because they prompt an a priori theorised approach to research design, analysis and critical appraisal based on a visual portrayal of causal relationships between variables. Methods: Three different approaches to drawing DAGs were compared in third year MBChB stude...
Article
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Evidence suggests national- and community-level interventions are not reaching women living at the economic and social margins of society in Pakistan. We conducted a 10-month qualitative study (May 2010-February 2011) in a village in Punjab, Pakistan. Data were collected using 94 in-depth interviews, 11 focus group discussions, 134 observational se...
Article
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The health-care commissioning cycle is an increasingly powerful determinant of the health services on offer and the care that patients receive. This study focuses on the mobilisation and use of evidence relating to ethnic diversity and inequality. Objective To describe the patterns and determinants of evidence use relating to ethnic diversity and...
Article
Background This study explored the potential role that sleep, and sleep improvement, might play in the aetiology of obesity, using data from the first wave of the Understanding Society (USoc) cohort – a longitudinal household panel study representative of the UK population. Methods The first wave of USoc collected data on seven self-reported sleep-...
Article
Full-text available
Previous studies of the pouched mouse (Saccostomus campestris) have revealed that during reproduction there is no increase in food consumption. although resting energy demands, measured by respirometry, increase substantially. One explanation for this anomalous situation is that these mice may routinely use torpor to compensate their energy budgets...