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Mireille E Schnitzer - One of the best experts on this subject based on the ideXlab platform.
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educational note paradoxical collider effect in the analysis of non Communicable Disease epidemiological data a reproducible illustration and web application
International Journal of Epidemiology, 2019Co-Authors: Miguel Angel Luquefernandez, Michael Schomaker, Daniel Redondosanchez, Maria Jose Sanchez Perez, Anand Vaidya, Mireille E SchnitzerAbstract:Classical epidemiology has focused on the control of confounding, but it is only recently that epidemiologists have started to focus on the bias produced by colliders. A collider for a certain pair of variables (e.g. an outcome Y and an exposure A) is a third variable (C) that is caused by both. In a directed acyclic graph (DAG), a collider is the variable in the middle of an inverted fork (i.e. the variable C in A → C ← Y). Controlling for, or conditioning an analysis on a collider (i.e. through stratification or regression) can introduce a spurious association between its causes. This potentially explains many paradoxical findings in the medical literature, where established risk factors for a particular outcome appear protective. We use an example from non-Communicable Disease epidemiology to contextualize and explain the effect of conditioning on a collider. We generate a dataset with 1000 observations, and run Monte-Carlo simulations to estimate the effect of 24-h dietary sodium intake on systolic blood pressure, controlling for age, which acts as a confounder, and 24-h urinary protein excretion, which acts as a collider. We illustrate how adding a collider to a regression model introduces bias. Thus, to prevent paradoxical associations, epidemiologists estimating causal effects should be wary of conditioning on colliders. We provide R code in easy-to-read boxes throughout the manuscript, and a GitHub repository [https://github.com/migariane/ColliderApp] for the reader to reproduce our example. We also provide an educational web application allowing real-time interaction to visualize the paradoxical effect of conditioning on a collider [http://watzilei.com/shiny/collider/].
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educational note paradoxical collider effect in the analysis of non Communicable Disease epidemiological data a reproducible illustration and web application
arXiv: Methodology, 2018Co-Authors: Miguel Angel Luquefernandez, Michael Schomaker, Daniel Redondosanchez, Maria Jose Sanchez Perez, Anand Vaidya, Mireille E SchnitzerAbstract:Classical epidemiology has focused on the control of confounding but it is only recently that epidemiologists have started to focus on the bias produced by colliders. A collider for a certain pair of variables (e.g., an outcome Y and an exposure A) is a third variable (C) that is caused by both. In a directed acyclic graph (DAG), a collider is the variable in the middle of an inverted fork (i.e., the variable C in A -> C <- Y). Controlling for, or conditioning an analysis on a collider (i.e., through stratification or regression) can introduce a spurious association between its causes. This potentially explains many paradoxical findings in the medical literature, where established risk factors for a particular outcome appear protective. We use an example from non-Communicable Disease epidemiology to contextualize and explain the effect of conditioning on a collider. We generate a dataset with 1,000 observations and run Monte-Carlo simulations to estimate the effect of 24-hour dietary sodium intake on systolic blood pressure, controlling for age, which acts as a confounder, and 24-hour urinary protein excretion, which acts as a collider. We illustrate how adding a collider to a regression model introduces bias. Thus, to prevent paradoxical associations, epidemiologists estimating causal effects should be wary of conditioning on colliders. We provide R-code in easy-to-read boxes throughout the manuscript and a GitHub repository (this https URL) for the reader to reproduce our example. We also provide an educational web application allowing real-time interaction to visualize the paradoxical effect of conditioning on a collider this http URL.
Miguel Angel Luquefernandez - One of the best experts on this subject based on the ideXlab platform.
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educational note paradoxical collider effect in the analysis of non Communicable Disease epidemiological data a reproducible illustration and web application
International Journal of Epidemiology, 2019Co-Authors: Miguel Angel Luquefernandez, Michael Schomaker, Daniel Redondosanchez, Maria Jose Sanchez Perez, Anand Vaidya, Mireille E SchnitzerAbstract:Classical epidemiology has focused on the control of confounding, but it is only recently that epidemiologists have started to focus on the bias produced by colliders. A collider for a certain pair of variables (e.g. an outcome Y and an exposure A) is a third variable (C) that is caused by both. In a directed acyclic graph (DAG), a collider is the variable in the middle of an inverted fork (i.e. the variable C in A → C ← Y). Controlling for, or conditioning an analysis on a collider (i.e. through stratification or regression) can introduce a spurious association between its causes. This potentially explains many paradoxical findings in the medical literature, where established risk factors for a particular outcome appear protective. We use an example from non-Communicable Disease epidemiology to contextualize and explain the effect of conditioning on a collider. We generate a dataset with 1000 observations, and run Monte-Carlo simulations to estimate the effect of 24-h dietary sodium intake on systolic blood pressure, controlling for age, which acts as a confounder, and 24-h urinary protein excretion, which acts as a collider. We illustrate how adding a collider to a regression model introduces bias. Thus, to prevent paradoxical associations, epidemiologists estimating causal effects should be wary of conditioning on colliders. We provide R code in easy-to-read boxes throughout the manuscript, and a GitHub repository [https://github.com/migariane/ColliderApp] for the reader to reproduce our example. We also provide an educational web application allowing real-time interaction to visualize the paradoxical effect of conditioning on a collider [http://watzilei.com/shiny/collider/].
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educational note paradoxical collider effect in the analysis of non Communicable Disease epidemiological data a reproducible illustration and web application
arXiv: Methodology, 2018Co-Authors: Miguel Angel Luquefernandez, Michael Schomaker, Daniel Redondosanchez, Maria Jose Sanchez Perez, Anand Vaidya, Mireille E SchnitzerAbstract:Classical epidemiology has focused on the control of confounding but it is only recently that epidemiologists have started to focus on the bias produced by colliders. A collider for a certain pair of variables (e.g., an outcome Y and an exposure A) is a third variable (C) that is caused by both. In a directed acyclic graph (DAG), a collider is the variable in the middle of an inverted fork (i.e., the variable C in A -> C <- Y). Controlling for, or conditioning an analysis on a collider (i.e., through stratification or regression) can introduce a spurious association between its causes. This potentially explains many paradoxical findings in the medical literature, where established risk factors for a particular outcome appear protective. We use an example from non-Communicable Disease epidemiology to contextualize and explain the effect of conditioning on a collider. We generate a dataset with 1,000 observations and run Monte-Carlo simulations to estimate the effect of 24-hour dietary sodium intake on systolic blood pressure, controlling for age, which acts as a confounder, and 24-hour urinary protein excretion, which acts as a collider. We illustrate how adding a collider to a regression model introduces bias. Thus, to prevent paradoxical associations, epidemiologists estimating causal effects should be wary of conditioning on colliders. We provide R-code in easy-to-read boxes throughout the manuscript and a GitHub repository (this https URL) for the reader to reproduce our example. We also provide an educational web application allowing real-time interaction to visualize the paradoxical effect of conditioning on a collider this http URL.
Luke Allen - One of the best experts on this subject based on the ideXlab platform.
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estimating the impact of achieving turkey s non Communicable Disease policy targets a macro simulation modelling study
The Lancet Regional health. Europe, 2021Co-Authors: Joao Breda, Luke Allen, Birol Tibet, Toker Erguder, Erdem Karabulut, Hasan Huseyin Yildirim, Alexander Mok, Kremlin WickramasingheAbstract:Summary Background The Burden of non-Communicable Disease (NCDs) has continued to rise globally, particularly in low- and middle-income countries. In Turkey, NCDs account for 89% of all deaths, with nearly one in five deaths occurring before age 70. This study investigates the number of NCD deaths that could be prevented if Turkey met national and international targets for major modifiable NCD risk factors. Methods Preventable deaths were estimated using the World Health Organization (WHO) ‘Preventable Risk Integrated ModEl’ (PRIME), by combining: 1) Baseline exposure data for risk factors, referenced from national surveillance and cohort studies; 2) Aetiological associations from published meta-analyses; and 3) Demographic and mortality statistics obtained from the Turkish Statistical Institute (TurkStat). Confidence intervals were estimated using Monte Carlo simulations. Findings If Turkey met its NCD risk factor targets for reducing tobacco and salt consumption by 30%, and physical inactivity by 10% in 2017, an estimated 19,859 deaths (95%CI: 12,802 to 26,609) could have been prevented. Approximately two thirds of these preventable deaths were in men, and one in three were in adults below 75 years. A 30% relative reduction in the consumption of alcohol, tobacco, and salt, as well as physical inactivity, would prevent 180 (107 to 259); 4,786 (3,679 to 5,836); 13,112 (5,819 to 19,952); and 7,124 (5,053 to 9,212) deaths, respectively. Interpretation Among major modifiable NCD risk factors, population-level reductions in salt intake and physical inactivity present the greatest opportunity for reducing NCD mortality in Turkey. These findings can help Turkey prioritise interventions to meet the Sustainable Development Goal target of reducing NCD mortality by one third, by 2030.
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implementation of non Communicable Disease policies a geopolitical analysis of 151 countries
The Lancet Global Health, 2020Co-Authors: Luke Allen, Brian D Nicholson, Beatrice Y T Yeung, Francisco GoianadasilvaAbstract:Summary Background Most countries have endorsed WHO non-Communicable Disease (NCD) best buy policies, but we know very little about global implementation patterns and about the geopolitical factors affecting implementation. We aimed to assess global implementation based on analysis of multiple geopolitical datasets. Methods We used the 2015 and 2017 WHO NCD progress monitor reports to calculate aggregate implementation scores for 151 countries, based on their implementation of 18 WHO-recommended NCD policies. We ranked all countries and used descriptive statistics to analyse global trends. We used linear regression to assess the associations between policy implementation and World Bank geographic region, risk of premature NCD mortality, percentage of all deaths caused by NCDs, World Bank income group, human capital index, democracy index, and tax burden. Findings In 2017, the mean NCD policy implementation score was 49·3% (SD 18·4%). Costa Rica and Iran had the joint-highest implementation scores (86·1% of all WHO-recommended policies). Scores were lowest in Haiti and South Sudan (5·5%). Between 2015 and 2017, aggregate implementation scores rose in 109 countries and regressed in 32 countries. Mean implementation rose for all of the 18 policies except for those targeting alcohol and physical activity. The most commonly implemented policies were clinical guidelines, graphic warnings on tobacco packaging, and NCD risk factor surveys. Our multiple linear regression model explained 61·1% of the variance in 2017 aggregate scores (p Interpretation Implementation of WHO-recommended NCD policies is increasing over time. On average, countries implemented just under half of the NCD policies recommended by WHO in 2017. Nutrition-related policies saw gains, while those related to alcohol and physical activity were the most likely to have been dropped. Aggregate implementation scores tended to be highest in high-income countries that invest in health care and education. Funding National Institute for Health Research, Imperial College London, University of Oxford.
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socioeconomic status and non Communicable Disease behavioural risk factors in low income and lower middle income countries a systematic review
The Lancet Global Health, 2017Co-Authors: Luke Allen, Julianne Williams, Nick Townsend, Bente Mikkelsen, Nia Roberts, Charlie Foster, Kremlin WickramasingheAbstract:Summary Background Non-Communicable Diseases are the leading global cause of death and disproportionately afflict those living in low-income and lower-middle-income countries (LLMICs). The association between socioeconomic status and non-Communicable Disease behavioural risk factors is well established in high-income countries, but it is not clear how behavioural risk factors are distributed within LLMICs. We aimed to systematically review evidence on the association between socioeconomic status and harmful use of alcohol, tobacco use, unhealthy diets, and physical inactivity within LLMICs. Methods We searched 13 electronic databases, including Embase and MEDLINE, grey literature, and reference lists for primary research published between Jan 1, 1990, and June 30, 2015. We included studies from LLMICs presenting data on multiple measures of socioeconomic status and tobacco use, alcohol use, diet, and physical activity. No age or language restrictions were applied. We excluded studies that did not allow comparison between more or less advantaged groups. We used a piloted version of the Cochrane Effective Practice and Organisation of Care Group data collection checklist to extract relevant data at the household and individual level from the included full text studies including study type, methods, outcomes, and results. Due to high heterogeneity, we used a narrative approach for data synthesis. We used descriptive statistics to assess whether the prevalence of each risk factor varied significantly between members of different socioeconomic groups. The study protocol is registered with PROSPERO, number CRD42015026604. Findings After reviewing 4242 records, 75 studies met our inclusion criteria, representing 2 135 314 individuals older than 10 years from 39 LLMICs. Low socioeconomic groups were found to have a significantly higher prevalence of tobacco and alcohol use than did high socioeconomic groups. These groups also consumed less fruit, vegetables, fish, and fibre than those of high socioeconomic status. High socioeconomic groups were found to be less physically active and consume more fats, salt, and processed food than individuals of low socioeconomic status. While the included studies presented clear patterns for tobacco use and physical activity, heterogeneity between dietary outcome measures and a paucity of evidence around harmful alcohol use limit the certainty of these findings. Interpretation Despite significant heterogeneity in exposure and outcome measures, clear evidence shows that the burden of behavioural risk factors is affected by socioeconomic position within LLMICs. Governments seeking to meet Sustainable Development Goal (SDG) 3.4—reducing premature non-Communicable Disease mortality by a third by 2030—should leverage their development budgets to address the poverty-health nexus in these settings. Our findings also have significance for health workers serving these populations and policy makers tasked with preventing and controlling the rise of non-Communicable Diseases. Funding WHO.
Ralf Reintjes - One of the best experts on this subject based on the ideXlab platform.
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Communicable Disease control and health protection handbook
2012Co-Authors: Jeremy Hawker, Norman Begg, Iain Blair, Ralf Reintjes, Julius Weinberg, Karl EkdahlAbstract:Communicable Disease Control And Health Protection Handbook - Libros de Medicina - Enfermedades infecciosas - 67,20
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comprar Communicable Disease control and health protection handbook jeremy hawker 9781444335675 wiley
2012Co-Authors: Jeremy Hawker, Norman Begg, Iain Blair, Ralf Reintjes, Julius Weinberg, Karl EkdahlAbstract:Tienda online donde Comprar Communicable Disease Control And Health Protection Handbook al precio 70,56 € de Jeremy Hawker | Norman Begg | Iain Blair | Ralf Reintjes | Julius Weinberg | Karl Ekdahl, tienda de Libros de Medicina, Libros de Microbiologia y Enfermedades infecciosas - Enfermedades infecciosas
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benchmarking national surveillance systems a new tool for the comparison of Communicable Disease surveillance and control in europe
European Journal of Public Health, 2007Co-Authors: Ralf Reintjes, Martina Thelen, Ralf Reiche, Agnes CsohanAbstract:Background: Communicable Diseases do not respect national boundaries and are important challenges to health internationally. Considerable variation exists in the structure and performance of surveillance systems for Communicable Disease prevention and control. European Union (EU) countries should share ideas to improve the quality of surveillance systems. The study aims to support the improvement and integration of surveillance systems of Communicable Diseases in Europe while using benchmarking for the comparison of national surveillance systems. Methods: Surveillance systems from England and Wales, Finland, France, Germany, Hungary, and The Netherlands were described and analysed. After comprehensive data collection and validation by several European public health (PH) experts, a descriptive data analysis was carried out. Benchmarking processes were performed with selected criteria (e.g. case definitions, early warning applications, and outbreak investigations). After the description of benchmarks, best practices were identified and described. Results: Benchmarking of national surveillance systems is applicable as a new tool for the comparison of Communicable Disease control in Europe. The countries included in the study have in general well-functioning Communicable Disease control and prevention systems. Nevertheless, there are different strengths and weaknesses in various countries. Practical examples from the various surveillance systems were demonstrated and recommendations were given to policy makers. Conclusion: A gold standard of surveillance systems in various European countries is very difficult to achieve because of heterogeneity (e.g. in Disease burden, personal, and financial resources). However, to improve the quality of surveillance systems across Europe, it will be useful to benchmark the surveillance systems of all EU member states.
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Communicable Disease control handbook
2001Co-Authors: Jeremy Hawker, Norman Begg, Iain Blair, Ralf Reintjes, Julius WeinbergAbstract:Section 1 - introduction section 2 - common topics section 3 - Diseases section 4 - services and organization section 5 - Communicable Disease control in individual countries appendices - resources for the CCDC.
Alastair Van Heerden - One of the best experts on this subject based on the ideXlab platform.
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high prevalence of hiv and non Communicable Disease ncd risk factors in rural kwazulu natal south africa
Journal of the International AIDS Society, 2017Co-Authors: Alastair Van Heerden, Ruanne V Barnabas, Shane A Norris, Lisa K Micklesfield, Heidi Van Rooyen, Connie CelumAbstract:Introduction South Africa faces epidemics of HIV and non-Communicable Diseases (NCDs). The aim of this study was to characterize the prevalence of non-Communicable Disease risk factors and depression, stratified by HIV status, in a community with a high burden of HIV. Methods We conducted a home-based HIV counselling and testing study in KwaZulu-Natal, South Africa between November 2011 and June 2012. Contiguous households were approached and all adults ≥18 years old were offered an HIV test. During follow-up visits in January 2015, screening for HIV, depression, obesity, blood glucose, cholesterol and blood pressure were conducted using point-of-care tests. Results Of the 570 participants located and screened; 69% were female and 33% were HIV-positive. NCD risk factor prevalence was high in this sample; 71% were overweight (body mass index (BMI) 25 to 29.9 kg/m2) or obese (BMI≥30 kg/m2), 4% had hyperglycaemia (plasma glucose >11.0 mmol/l/200 mg/dl), 33% had hypertension (HTN, >140/90 mmHg), 20% had hyperlipidaemia (low density cholesterol >5.2 mmol/l/193.6 mg/dl) and 12% had major depressive symptoms (nine item Patient Health Questionnaire ≥10). Of the 570 participants, 87% had one or more of HIV, hyperglycaemia, HTN, hyperlipidaemia and/or depression. Over half (56%) had two or more. Older age and female gender were significantly associated with the prevalence of both HIV infection and NCD risk factors. Around 80% of both HIV-positive and negative persons had one of the measured risk factors (i.e. obesity, hyperglycaemia, hyperlipidaemia, HTN), or depression. Conclusions In a community-based sample of adults in KwaZulu-Natal, South Africa, the prevalence of both HIV infection and NCD risk factors were high. This study is among the first to quantify the substantial burden of NCD risk factors and depression in this non-clinic based population.