Public Health Mini-Guide Obesity About the authors Nick Townsend is a Senior Researcher at Oxford University, UK. He leads on a programme of research into the epidemiology of cardiovascular disease (CVD) with a special interest in obesity and its associated risk factors. Nick has published widely on obesity as well as presenting findings at a number of UK and international conferences. He teaches on a range of graduate and postgraduate courses within the university and has also acted as a guest lecturer on the courses of other institutions. His research focuses on the complex determination of obesity, with a focus on policy interventions and the promotion of healthy behaviour in schools. Angela Scriven is a Reader in Health Promotion at Brunel University in London, UK. She has been teaching and researching in the field of health promotion for over 30 year and has published widely including authoring, editing or co-editing the following books Health Promotion Alliances: Theory and Practice (1998); Health Promotion: Professional Perspectives (1996; 2001 2nd edn); Promoting Health: Global Perspectives (2005); Health Promoting Practice: The Contribution of Nurses and Allied Health Professionals (2005); Public Health: Social Context and Action (2007); Promoting Health: A Practical Guide (2010); Health Promotion for Health Practitioners (2010); Health Promotion Settings: Principles and Practice (2012). Her research is centred on the relationship between health promotion policy and practice within specific contexts. She is a member of the International Union of Health Promotion and Education (IUHPE), is President Elect for the Institute of Health Promotion and Education (IHPE) and is a Fellow of the Royal Society for Public Health (RSPH). For Elsevier Content Strategist: Mairi McCubbin Content Development Specialist: Barbara Simmons Project Manager: Umarani Natarajan Designer/Design Direction: Miles Hitchen Public Health Mini-Guide Obesity Nick Townsend Senior Researcher, University of Oxford, Oxford, UK Angela Scriven Reader in Health Promotion, Brunel University, London, UK Series editor: Angela Scriven Edinburgh London New York Oxford Philadelphia St Louis Sydney Toronto 2014 © 2014 Elsevier Ltd. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. 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To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. The Publisher's policy is to use paper manufactured from sustainable forests Printed in China Titles in the Public Health Mini-Guide series: Obesity Nick Townsend, Angela Scriven ISBN 9780702046346 Alcohol Misuse (forthcoming) Ken Barrie, Angela Scriven ISBN 9780702046384 Diabetes (forthcoming) Josie Evans, Angela Scriven ISBN 9780702046377 Series preface The UK Government highlighted in the Foreword to its strategy for public health in England, the Healthy Lives, Healthy People White Paper1 some of the public health challenges that are facing those working to improve public health: ‘Britain is now the most obese nation in Europe. We have among the worst rates of sexually transmitted infections recorded, a relatively large population of problem drug users and rising levels of harm from alcohol. Smoking alone claims over 80,000 lives in every year. Experts estimate that tackling poor mental health could reduce our overall disease burden by nearly a quarter. Health inequalities between rich and poor have been getting progressively worse’. The public health targets are clear both in the White Paper and in Our Health and Wellbeing Today,2 published to accompany the White Paper, with the targets being supplemented by further policy drivers for mental health, tobacco control, obesity, sexual health and the wider determinants. The proposals and identified priorities in the White Paper apply to England, but they are of equal concern in the Devolved Administrations and globally, as evidenced in World Health Organization reports (www.who.int/whr/en/index.html). The Public Health Mini-Guides series covers some of the key health targets identified by the UK Government and WHO. The Mini-Guides highlight, in a concise, easily accessible manner, what the problems are and the range of potential solutions available to those professionals with a responsibility to promote health. What the Public Health Mini-Guides provide The Mini-Guides are written to provide up-to-date, evidence-based information in a convenient pocket-sized format, on a range of current key public health topics. They will support the work of health and social care practitioners and students on courses related to public health and health promotion. Each volume provides an objective and balanced introduction to an overview of the epidemiological, scientific, and other factors relating to public health. The Mini-Guides are structured to provide easy access to information. The first chapters cover background information needed to quickly understand the issue, including the epidemiology, demography and physiology. The later chapters examine examples of public health action to address the issue, covering health promotion Series preface intervention, legislative and other measures. The Mini-Guides are designed to be essential reference texts for students, practitioners and researchers with a professional interest in public health and health promotion. Uxbridge, 2012 Angela Scriven References 1. The Stationery Office. Healthy Lives, Healthy People. White Paper. 2010. 2. Department of Health. Our Health and Wellbeing Today. London: Department of Health; 2010. viii Preface Obesity and its linked morbidity and mortality place a burden not only on the individual but also on society as a whole. It is a significant public health challenge on a global scale. This Mini Guide presents key themes relating to this challenge, including the means of measuring obesity, the most recent prevalence and trends, and the health consequences and causes of obesity, along with approaches to counter obesity both at an individual and a population level. Chapter 1 starts with defining obesity, and then critiques the various measures by assessing their strengths and weaknesses. Obesity in children and the use of growth charts is considered alongside the range of thresholds available (UK90, CDC, IOTF, WHO) and an explanation of the difficulties in using them. The chapter finishes with a short piece on the adiposity rebound and evidence of predicting future obesity. Chapter 2 covers prevalence and trends with regional, ethnic and social differences in prevalence in the UK compared to international data and estimated future trends. Chapter 3 examines the health consequences of obesity, highlighting any extra complications from obesity in childhood. Relative risks, where available, of some of these morbidities are presented. Causal pathways are discussed and the difficulty in separating obesity as a risk factor is explained alongside the evidence of obesity related mortality. Chapter 4 covers the causes of obesity and their interrelations and demonstrates the complex nature of the determination of obesity. Chapter 5 deals with ways of combating obesity at the individual level with description of how to treat obese individuals, from diet and exercise to medical intervention including NICE recommendations. Chapter 6 assesses how to intervene at a population rather than individual level, introducing a public health approach to preventing obesity, including policy impacts. Each chapter covers important content on these themes with suggestions on where readers can find more information through links to webpages, resources and further reading. Understanding is facilitated through Case Studies, examples in Boxes, Thinking Points and an end-of-chapter set of Summary Points. 1 Defining the obesity problem a General Practice (GP) surgery is What is obesity? routinely measuring patients visiting Obesity is a medical condition their practice in order to identify characterised by an excess of adipose those who are overweight or obese, tissue (fat) in the body that may have it is important that when individuals adverse effect on the health of an are classified within high-risk weight individual1–4 (see Chapter 3 for detailed status thresholds, they receive suitable coverage of the health risks of obesity). treatment to enable them to reduce The World Health Organization their weight in a healthy manner. (WHO) similarly defines overweight Surveillance programmes The aim and obesity as abnormal or excessive here is to monitor the levels of obesity fat accumulation that presents a risk to in a population rather than to identify health.5 This is an important definition, those who require treatment.9–11 as it indicates what to measure when Within surveillance programmes, data investigating obesity. are usually anonymised, meaning that no routine feedback of individualised Measuring obesity results is provided, nor is any formal link to treatment maintained. Data Screening programmes These collected from these programmes are large-scale programmes that enable the identification and identify those who are at risk from monitoring of trends over time and obesity-related ill health. They assist in the targeting of interventions. should be accompanied by an Additionally, information from explicit intention to prevent and also surveillance programmes may be reduce the prevalence of obesity in used to analyse different causal and the population.6–9 For example, if contributory factors for overweight Public Health Mini-Guides: Obesity and obesity, supporting the On occasions programmes may development of effective interventions straddle the line between screening and and public health approaches to surveillance, such as the National Child tackle obesity12,13 (see Chapter 6 for Measurement Programme (NCMP) in an overview of public health obesity England (see the NCMP Case Study in interventions). Box 1.1). Thinking points 1. Some people object to the collection of measurements related to obesity, although screening for other health conditions is welcomed; why is there this disparity? 2. What unintended harms can arise from running obesity measuring programmes? 3. Is it ethically sound to run a surveillance programme in which those identified as at risk of ill health are not informed? 4. With changes to the NHS in England, the running of the NCMP may have to change; should it be retained, and what should be saved in order to link future obesity measurement findings to earlier data? Box 1.1 Case study: National Child Measurement Programme The National Child Measurement Programme (NCMP) for England was established in 2005/06. The NCMP collects population-level surveillance data for children through taking annual measurements of height and weight for Reception year (typically aged 4–5 years) and Year 6 (typically aged 10–11 years) primary school pupils.14 The measurement exercise was coordinated locally by Primary Care Trusts (PCTs) with the support and cooperation of schools.15 PCTs were freestanding statutory bodies of the National Health Service (NHS) that had the responsibility for securing the provision of a full range of primary care services for the local populations. There were 152 PCTs covering all of England within which the collection of NCMP data was coordinated. However, changes to the structure of the NHS under the Health and Social Care Bill 2011 announced the abolishment of PCTs by 2013, with the public health aspects of the PCTs taken on by local councils.16 With the abolition of the PCTs, responsibility for NCMP measurement was taken on by Local Authorities with central collation of the data conducted by the Health and Social Care Information Centre (HSCIC) which was formally known as the NHS Information Centre. With the abolition of the PCTs in 2013 this measurement became the responsibility of Local Authorities. Authorities can undertake measurements at any time during the school year.17 Height and weight measurements are taken by health professionals, Continued 2