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PID13 5/21/04 11:39 AM Page 96 Chapter 13 Health promotion and health education Introduction The terms health promotion and health education are sometimes confused Both are strategies aimed at improving the public health, but while the concepts are complementary they are not synonymous Health promotion involves the empowerment of the community in improving its health through education, through the provision of preventive health services and by improvement of the social, physical and economic environments Health education is the empowerment of individuals through increased knowledge and understanding, but does not involve the political advocacy necessary in health promotion The health strategies that emerged during the 19th century were in some ways similar to those that we now term health promotion Thus, Medical Officers of Health worked for local authorities with the aim of improving the environment, encouraging healthy public policies, introducing preventive strategies (e.g sanitation and vaccination) and encouraging better health through education Another step in the development of health promotion was the Peckham Pioneer Health Centre project, which began in south London in the 1930s It provided conventional health care and health education together within an environment that supported community development through the provision of recreational and sports facilities 96 The new public health A new public health initiative was heralded by the Lalonde Report for the Canadian Government (1974), which incorporated health promotion as an integral part of the government strategy to improve public health Lalonde identified four main influences on people’s health Lalonde’s four health factors Genetic and biological factors Behavioural and attitudinal factors—the so-called lifestyle factors Environmental factors, which include economic, social, cultural and physical factors The organization of health care systems A growing awareness of the factors that influence health encouraged people with an interest in prevention to involve organizations and institutions not usually primarily concerned with health This led to the concept of Healthy Cities, which also originated in Canada and was subsequently embraced by the World Health Organization (WHO), spreading throughout the world In the UK, many health promotion initiatives were coordinated under this umbrella, first in Liverpool and later in Manchester, Newcastle, Camden, Belfast and Glasgow More information about Healthy PID13 5/21/04 11:39 AM Page 97 Health promotion and education Chapter 13 Cities can be found at the WHO website www.who.dk/healthy-cities/ At the same time the role of the UK Health Education Council, which was set up in 1968, was expanded to include public policy advice and social and environmental issues in addition to the provision and distribution of health education material The key components of health promotion were defined in a charter agreed at the first International Conference on Health Promotion held in Ottawa in 1986 This suggested a definition of health promotion and five key areas for action The Ottawa Charter stated that: Health Promotion is the process of enabling people to increase control over, and to improve, their health To reach a state of complete physical, mental and social well-being, an individual or group must be able to identify and to realize aspirations, to satisfy needs and to change or cope with the environment Health is therefore seen as a resource for everyday life, not the objective of living Health is a positive concept emphasizing social and personal resources, as well as physical capabilities Therefore, health promotion is not just the responsibility of the health sector, but goes beyond healthy life-styles to well-being It also proposed that: ‘health promotion should focus on equity in health and reducing differences in health status by ensuring equal opportunities and resources to enable all people to achieve their fullest health potential’ The five areas for health promotion action were as follows The Ottawa Charter Building healthy public policy Creating supportive environments Strengthening community action Developing personal skills Reorientating the health services Building healthy public policy To encourage policy makers in organizations and government to place health on their agenda This may include efforts to identify and remove obstacles to healthy policies so that these become the easier choice Creating supportive environments To create living and working conditions that are safe, stimulating, satisfying and enjoyable To encourage communities to care for each other, and to take responsibility for the conservation of natural resources Strengthening community action To work through effective community action in setting priorities, making decisions, planning strategies and implementing them to achieve better health Developing personal skills To support social and personal development through the provision of information, health education and the development of individual skills Reorientating the health services To encourage health service providers to look beyond their mandate for clinical and curative services and ensure that health services are aimed at the pursuit of health rather than only the cure of illness The principles of the Ottawa Charter were adopted in various ways by many countries throughout the world, but the initial enthusiasm seems to have waned The UK adopted health targets in line with ‘Health for All by the Year 2000’ in 1990, and in 1999 a new set of goals were outlined in Our Healthier Nation These targets are aimed primarily at action by the health services without a commitment to changes in public policy They include targets to improve health outcomes in relation to cancer, coronary heart disease and stroke, accidents and mental health There are a number of difficulties in adopting the health promotion approach The long interval between the adoption of preventive strategies and measurable improvements in health means that organizations see little short-term return on their investment The processes of community consultation, health education and altering public policies are time consuming, and are often politically controversial Many health promotion programmes have been initiated without a clear commitment to evaluate 97 PID13 5/21/04 11:39 AM Page 98 Chapter 13 Health promotion and education their outcomes Given the limited health budget, it is not acceptable to institute unproven interventions, whether they involve conventional medical treatment or a health promotion programme, unless they are rigorously and scientifically tested The emphasis that many politicians and others have placed on personal responsibility for health has been criticized because it ignores the economic and social influences This can be illustrated by considering smokers who suffer ill health They are blamed for the outcome of their voluntary action whilst the advertising of tobacco products in many countries continues to be permitted and the companies who promote them take no responsibility for the adverse outcome Similarly, children who grow up in impoverished homes, lacking education and with little hope of employment, have bleak futures and may be unable to respond to the admonition of those from more privileged backgrounds to change their ways (These issues were discussed in the Black Report referred to on p 5.) Another issue relating to the effectiveness of health promotion programmes concerns the dilemma of whether to adopt a population strategy or a targeted strategy The former involves attempting to achieve health gain through actions involving the whole population while the latter focuses efforts on particular risks associated with specific conditions Both approaches have their adherents, but scientific evaluation of their comparative effectiveness is needed before one approach or another is taken An example of a population approach was the North Karelia Community trial, which aimed to reduce the incidence of heart disease in a Finnish community by means of changes in people’s diet, smoking habits and exercise compared with a control community Health promotion campaigns targeted at particular groups have also been used successfully, for example in the effort to reduce the spread of HIV amongst intravenous drug users by the introduction of needle-exchange schemes In the UK many different professional groups and lay organizations are involved in health education and health promotion 98 Health promotion in the UK The Health Development Agency is the Department of Health’s health promotion arm and succeeded the Health Education Agency in January 2000 Its website is http://www.hdaonline.org.uk/ The Agency is a special health authority Its aim is to identify the evidence of what works to improve people’s health and reduce health inequalities Then, in partnership with professionals, policy makers and practitioners, it will develop guidance and work across sectors to get evidence into practice Members of the Board of the Authority are appointed by the Secretary of State for Health and include leading figures from health, associated professions, the media, education and related fields Primary care trusts are also charged with improving the health of the population for which they are responsible Most of their budgets are committed to the provision of personal health services, but some of their resources are allocated to health promotion Often this is through specialist health promotion staff These staff use a combination of health education and community support to target particular issues They tend to concentrate on high-profile issues such as cervical cancer, HIV or heart disease Voluntary bodies, such as the Royal Society for the Prevention of Accidents, the British Heart Foundation, Cancer UK or environmental groups such as Greenpeace and the Friends of the Earth are all active in health promotion Their contribution to the provision of knowledge to individuals, influence on public policy and help in reorientating the health services is increasingly recognized Health promotion programmes There are many different health promotion programmes Some leading examples of current activities are outlined below PID13 5/21/04 11:39 AM Page 99 Health promotion and education Chapter 13 Health promotion Target areas include: • Smoking • Alcohol • Nutrition • Exercise • Sexuality nicotine replacement therapy This is another example of how the health service can begin to move from providing a curative approach to one where prevention and education is the goal It is important to remember that most people start smoking when they are teenagers and thus strategies targeted at children have also been encouraged, for example getting local authorities to enforce the law on sales of cigarettes to the under 16s Smoking Strategies to reduce smoking The UK has a long history of providing information about the dangers of smoking through government-funded campaigns, advice from general practitioners and health campaigns in schools Punitive tax on tobacco is one public health policy, which has been shown to be effective in reducing smoking A 10% rise in price has been associated with a 1% reduction in smoking Banning the sale of cigarettes to children under the age of 16 years and the prohibition of smoking in certain public places are other examples of relevant legislative policies The banning of advertising in countries such as Canada and New Zealand has been shown to reduce tobacco consumption, and the UK and Europe are now following suit Many companies and hospitals have attempted to create healthier environments by the introduction of no-smoking policies Some have also funded smoking cessation support for their staff Cinemas, airlines and some restaurants now ban smoking In March 2004 the Republic of Ireland passed legislation to ban smoking in public places such as pubs and resturants Little is done to support voluntary organizations financially in their campaigns against tobacco A Canadian campaign involving health authorities, Action on Smoking and Health (ASH) and the Canadian Cancer Society demonstrated the effectiveness of combined action in achieving a ban on tobacco advertising in that country One of the goals that general practitioners have been set as part of the National Service Framework on Cardiovascular Disease involves identifying the number of tobacco smokers within their practice They can then refer them to smoking cessation clinics or prescribe supportive treatment such as • • • • • • Increase the price of cigarettes Ban advertising Ban smoking in the work place and public places Identify and counsel current smokers Provide smoking cessation clinics Enforce the law on sales to children Alcohol Alcohol abuse is of increasing concern It is estimated that in the UK up to 40 000 deaths per year are alcohol related, including a significant proportion of the 3500 road deaths Cirrhosis of the liver is now four times more common in middle-aged men than it was in the 1970s Public policies relating to alcohol include the imposition of excise duties and the passing of licensing laws The UK has among the highest rates of tax on alcohol in the EU The licensing laws were introduced initially to control the ‘gin palaces’ of the 18th and 19th centuries Paradoxically, these laws are now being relaxed Another policy intervention aimed at reducing alcohol-related deaths was the passing of the drink–driving laws This has resulted in a considerable reduction in the number of deaths on the roads Doctors have not always been good advocates or role models for the prevention of alcohol abuse The tradition of medical student drinking can lead to the development of unhelpful professional and personal attitudes to drink Strategies aimed at creating supportive environments to contain the abuse of alcohol should include offering people healthy choices, for example putting water on the table at mealtimes both in the home and when eating in restaurants Offering food in pubs and other 99 PID13 5/21/04 11:39 AM Page 100 Chapter 13 Health promotion and education places where alcohol is served also encourages more responsible drinking Education includes giving people information about safer drinking levels and publicizing the existence of help agencies Often, conflicting information about the health benefits of moderate drinking is preferentially heard, perhaps encouraging light drinkers to drink more whilst doing nothing to encourage the heavy drinker to reduce intake Advice on dealing with alcohol abuse can be provided to individuals To this those people with a problem need to be identified Simple screening questionnaires on all at-risk patients can be used both in hospital practice and in primary care Strategies to reduce harm from alcohol abuse • • • • • Increase the price of alcohol Drink–driving laws Make water and soft drinks easily available Only offer alcohol with food Identify and counsel problem drinkers Nutrition The subject of nutrition is full of mixed messages, due to the paucity of consistent scientific evidence on the health effects of dietary change In most parts of the world, malnutrition is the greatest threat to health In the developed world, obesity is now a major problem Public policy in the field of nutrition has been scant and poorly coordinated The Health of the Nation document published by the UK DoH in 1990 promoted a reduction in the percentage of food energy derived from fat and also aimed to reduce the prevalence of obesity Despite this there has been a year-on-year increase in the prevalence of obesity There are differential tax (VAT) rates on some foods, but legislation concerning food is generally aimed at minimizing known hazards rather than supporting nutritional objectives Education about diet is widespread and often most effectively undertaken by food manufacturers, for example encouraging the consumption of cereals, and the choice of margarine or vegetable 100 oils rather than animal fats Whilst a population approach to nutrition is attractive, the use of a targeted approach in certain situations is also valuable For example, preconception advice for women concerning their intake of folate will reduce the risk of them having a baby with a neural tube defect Perhaps more could be done to improve nutrition through the adoption of nutritional policies For instance, one initiative by the Department of Health has been the ‘Five a Day’ programme which has been taken up by a number of primary care trusts and aims to get at-risk populations to eat five portions of fruit and vegetables a day The Government has also launched the ‘Food in Schools’ programme which aims to improve school children’s knowledge about healthy nutrition This programme was launched through the British Nutrition Foundation (http://www.nutrition.org.uk/) The other important body is the Scientific Advisory Committee on Nutrition (SACN) This is a UKwide advisory committee set up to provide advice on scientific aspects of nutrition and health This includes advice on the nutrient content of individual foods and advice on diet as a whole including the definition of a balanced diet, and the nutritional status of people They are also consulted on nutritional issues that affect wider public health policy issues including conditions where nutritional status is one of a number of risk factors (e.g cardiovascular disease, cancer, osteoporosis and/or obesity) The website is http://www.sacn.gov.uk/ Strategies to improve nutrition • Education through the media • No tax on healthy foods • Targeted messages, e.g folic acid for pregnant women • Scientific advice available to policy makers • Introduce nutrition on the school curriculum Exercise The health benefits of exercise are widely recognized and yet its promotion is often uncoordinated This is one area where public policy could PID13 5/21/04 11:39 AM Page 101 Health promotion and education Chapter 13 have great influence Some new towns in the 1970s were designed with cycle paths and well-lit walkways to encourage healthy options for getting to and from work The majority of local authorities have invested in sports facilities and made them available at subsidized rates, but many schools sold their sports grounds in the 1990s thus discouraging children from taking part in regular sports Recently this has been counteracted by a new ‘PE and Sports Programme’ funded through local authorities with the aim of increasing the provision and use of sports facilities The ‘Healthy Schools Programme’ has also emphasized the importance of physical activity to children Knowledge about the benefits of exercise has increased dramatically over the last two decades This information is now being passed on by doctors to their patients Patients may be referred to rehabilitation programmes, which increasingly emphasize the value of physical fitness Much of this activity is in the form of tertiary prevention, as after a heart attack However recent randomized controlled trials have shown the benefit of regular exercise as a primary prevention strategy to reduce the risk of developing diabetes Strategies to increase exercise • Healthy public policy, e.g cycle tracks • Increasing the provision of sports facilities • Sports in schools programmes • Exercise for high-risk patients, e.g to prevent diabetes • Part of rehabilitation programmes, e.g after a heart attack statements by the GMC and BMA about the prescribing of the pill to girls below the age of consent The Government has a policy of providing free contraceptive services through general practitioners and family planning services, but ease of access to services has to be complemented by appropriate knowledge and behaviour This is best encouraged through health education and by providing supportive environments The change in attitude to the advertisement of condoms on television and their widespread availability through supermarkets and other retail outlets was brought about by a need to promote a change in behaviour to try to reduce the spread of HIV This has had an effect on other STDs as well as making people more aware of the risks of unwanted pregnancy This example shows how one health issue cannot always be separated from others Some changes in health services seem to happen by accident Making the oral contraceptive available only on a doctor’s prescription placed a clear responsibility on doctors, involving them in their patients’ sexual behaviour General practitioners in particular accepted this responsibility so that now family planning advice is a major part of their work The medicalization of contraception led doctors to become involved in a number of other initiatives such as cervical screening and well women clinics The pill has thus been a very successful influence in reorientating doctors towards providing preventive rather than curative health care Ethics of health promotion Sexually transmitted disease and unwanted pregnancy Improving health through changes in sexual behaviour will help reduce the number of unwanted pregnancies and sexually transmitted diseases (STDs) The laws designed to prevent underage sexual intercourse little to reduce the incidence of teenage pregnancies This growing problem and the obvious need for contraception led to policy The ethics of health promotion can be approached using the four principles often used when considering individual care Ethical principles • • • • Rights and responsibilities Beneficence Non-maleficence Justice 101 PID13 5/21/04 11:39 AM Page 102 Chapter 13 Health promotion and education A key conflict arises between the goals of health promotion and the rights of individuals to personal autonomy People working in health promotion sometimes seek restrictions on personal behaviour in the interests of the public good This can lead to conflict with a significant sector of the public who wish to retain their autonomy of decision-making Most agree that where the autonomy of others is threatened such as by drunk drivers on the road, it is reasonable for society to intervene However, legislating against personal risk-taking is more controversial There are no laws preventing mountaineering or bungee jumping, although there is legislation on the use of seat belts, which are only of benefit to the individual concerned Similarly, the use of certain drugs is illegal although they usually only directly affect the individual user Thus, the law and public attitudes on these issues are not always consistent In relation to beneficence and non-maleficence, in many situations the amount of good or the amount of harm that may arise from many health promotion initiatives is not known This is not a reason for inaction, but the community is entitled 102 to answers to allow it to make informed decisions Often the initiative to mount a preventive health programme is undertaken without proper consultation with the community This is contrary to the philosophy of health promotion, but is often due to ignorance on how to undertake community consultation As far as justice is concerned, it could be argued that funds should only be spent when there is a good prospect of benefit to the health of the public This has been recognized by the Health Development Agency who have developed the HDA Evidence Base so that health promotion programmes of proven effectiveness can be pursued With regard to the targeting of programmes the ethics of a population-based approach must also be considered in the context of the needs to reduce the inequities in health between the poor and the rich These considerations suggest that all health promotion campaigns should at least be submitted to an ethical review before being implemented, and that a facility should be in place to re-examine the issues as the programme progresses PID14 5/21/04 11:41 AM Page 103 Chapter 14 Control of infectious diseases Introduction Human An infectious or communicable disease is an illness caused by the transmission of a specific microbial agent (or its toxic products) to a susceptible host The agents can be bacteria, viruses or parasites The majority of microbes are harmless to humans Some, although not universally pathogenic, are potentially dangerous and may cause disease in unusual circumstances Caution is needed not to attribute a disease to an organism which happens to be present as a commensal or contaminant There are many factors that determine whether or not biological agents result in the spread of disease in a population They can be broadly divided into the presence of reservoirs of infection, the method of transmission, the susceptibility of the population or its individual members to the organism concerned, and the characteristics of the organism itself The human population is the reservoir of infection in diseases such as measles and chickenpox Were these organisms to be eliminated from humans, the diseases they cause would be eradicated in the same way that smallpox has been eradicated However, due to their high infectivity and ease of transmission, these diseases are difficult to eliminate despite the use of mass vaccination programmes In addition, some infections may be carried by non-symptomatic individuals who may transmit them to others Asymptomatic carriers are often difficult to identify Human carriers are of three types: healthy, convalescent or chronic Healthy carriers are people who are colonized by a potentially pathogenic organism without any detectable illness, for example staphylococcal carriage in the anterior nares or in the axilla, or coliforms in the gut Convalescent carriers are people who have recovered from the illness but who continue temporarily to excrete the organism, for example salmonellae in faeces Chronic carriers are people who, while remaining clinically well, may carry and excrete organisms continuously or intermittently over a prolonged period, for example typhoid carriers in whom Salmonella typhi may remain in the gallbladder for life Such carriers are a continuing threat to Reservoirs of infection A reservoir of infection is the site or sites in which a disease agent normally lives and reproduces Reservoirs of infection may be classified as human, other biological or environmental 103 PID14 5/21/04 11:41 AM Page 104 Chapter 14 Control of infectious diseases the community long after they recover from the disease Human immunodeficiency virus (HIV) is of particular interest because the reservoir of infection is human All carriers are infectious Infectivity is at its highest around the time of seroconversion often when HIV infection has yet to be diagnosed and again later when HIV disease (the symptomatic phase) occurs Transmission survival Organisms vary in their capacity to survive in the free state and to withstand adverse environmental conditions, for example heat, cold, dryness Sporeforming organisms, such as tetanus bacilli which can survive for years in a dormant state, have a major advantage over an organism like the Gonococcus which survives for only a very short time outside the human host Other biological or environmental These include: • animals, for example Escherichia coli, rabies, malaria, psittacosis and hydatids; • foodstuffs, for example Salmonella, Campylobacter and Listeria; • water, for example giardiasis, schistosomiasis and cholera; • soil and the environment, for example anthrax, Legionella, tetanus Life cycle The life cycle of certain organisms has important consequences in the spread of disease Organisms such as the malaria parasite which have a complex life cycle requiring a vector are more vulnerable than those with simpler requirements for transmission In many infections by such organisms, humans are an accidental host Host susceptibility Transmission Infectious diseases can be transmitted by various means and their mode of transmission influences the spread of disease through a community Interrupting the transmission of infectious agents is a key strategy for the control of these diseases Methods of transmission include the following Transmission • Direct contact — touching, kissing or sexual intercourse, e.g Staphylococcus, Gonococcus and HIV • Vertical transmission (mother to fetus), e.g hepatitis B, Listeria, HIV, rubella and cytomegalovirus • Inhalation of droplets containing the infectious agent, e.g tuberculosis, measles, influenza • Ingestion of food or water that is contaminated, e.g Salmonella, Giardia, Norwalk virus, hepatitis A • Injection either by human interference or by insects, e.g hepatitis B and C, tetanus, malaria Transmission is also affected by the conditions which organisms require for their survival and their life cycle 104 Host factors that influence the natural history of infectious diseases include the following Host factors • • • • • Age Gender Nutrition Genetics Immunity: natural, acquired and population Age The very young and the elderly are more susceptible to infectious diseases than are older children and younger adults However, some common diseases of childhood such as measles, mumps and chickenpox can be more serious when they occur in adolescents and young adults Gender There is some evidence that susceptibility to some infections differs with gender In general, males ex- PID14 5/21/04 11:41 AM Page 105 Control of infectious diseases Chapter 14 perience higher age-specific mortality rates than females for most diseases Nutrition The state of nutrition of the host is very important For example, in developing countries, measles may have a mortality of 5% amongst those who are poorly nourished whilst in the UK the case fatality rate is 0.02% It is likely that the improvement in nutrition during the 19th century was a major reason for the reduction in deaths from communicable diseases at that time Genetics Some individuals appear to have an exceptional susceptibility to infections, which is probably inherited This can be seen in the similar susceptibilities of monozygotic twins and different susceptibilities of dizygotic twins to certain infections In national or ethnic groups, natural selection over many generations may eventually breed a relatively resistant stock A good example of this phenomenon is the history of tuberculosis in Europe During the 19th century, the population experienced a high incidence of this disease which, by causing high mortality amongst susceptible young adults, tended to favour the survival through reproductive life of those with higher innate resistance By contrast, when an infectious disease is first introduced into a community with no prior experience of it, the result can be disastrous For example, the introduction of measles to the Greenland Inuits by the American forces during the Second World War caused devastating epidemics with high mortality Some genetic traits can be an advantage; for example, carriers of sickle-cell disease have a positive advantage when infected with malaria Immunity The occurrence of disease in humans depends upon the individual’s susceptibility to the agents to which he or she is exposed Defence mechanisms are natural and acquired immunity (see Chapter 15) and population (herd) immunity Population (herd) immunity The resistance of groups of people to the spread of infection is termed population (or herd) immunity It depends on the proportion of individuals in the population who are immune If this is sufficiently high, chains of transmission of the agent cannot be sustained because susceptible people in the group are shielded from exposure to infected people by the immune people around them The degree of herd immunity that will inhibit spread varies with different infections but is usually less than 100% It depends on: • the frequency of new introductions of infection; • the degree of mixing which affects opportunities for contact between infected and susceptible people; and • the transmissibility of the infection and duration of infectiousness of excreters Herd immunity affects the periodicity of epidemics So long as each case leads to more than one new infection, the incidence of the disease increases and herd immunity rises When herd immunity reaches a level at which each case causes less than one new infection, incidence declines As individual immunity wanes or new, susceptible people are introduced to the group, herd immunity again declines and the group is again vulnerable This was well illustrated by the periodic epidemics of measles, which occurred every 2–3 years before the introduction of measles vaccination (see Fig 3.4) Introduction of vaccination programmes lengthens the period between epidemics The higher the immunization rate, the longer the period If the antigenic composition of an infectious agent changes or if an agent previously absent from the population is introduced, there is no benefit from herd immunity against that organism and large-scale epidemics may result For example, antigenic changes of the influenza virus from time to time lead to worldwide pandemics Characteristics of the organism The characteristics of the causal organism are also pertinent to the spread of infectious diseases These include the following 105 PID21 5/21/04 11:49 AM Page 178 PIDAPP 5/21/04 11:50 AM Page 179 Appendices Further Reading and Useful Websites PIDAPP 5/21/04 11:50 AM Page 180 PIDAPP 5/21/04 11:50 AM Page 181 Appendix Suggested further reading Armitage P, Berry G Statistical Methods in Medical Research Oxford: Blackwell Science, 2001 Ashton J, Seymour H The New Public Health Open University Press, 1990 Beaglehole R, Bonita R, Kjellstrom T Basic Epidemiology World Health Organization, 1993 Benenson AS Control of Communicable Disease in Man American Public Health Association, 1997 Bland M An Introduction to Medical Statistics Oxford: Oxford University Press, 2000 Detels R, McEwen J, Beaglehole R, Tanaka H Oxford Textbook of Public Health Oxford University Press, 2002 Donaldson RJ, Donaldson LJ Essential Public Health Medicine, 2nd edn Petroc Press, 2000 Drummond MF, Maynard A Purchasing and Providing Cost-Effective Health Care Churchill Livingstone, 1997 Greenhalgh T How to Read a Paper BMJ Publications, 2001 Joint Committee on Vaccination and Immunisation Immunisation Against Infectious Diseases London: HMSO, 1996 McKeown T The Role of Medicine Oxford: Basil Blackwell, 1980 Naidoo J, Wills J Health Promotion Foundations for Practice, UK Second edition Bailliere Tindall, 2000 Pereira-Maxwell F A–Z of Medical Statistics Oxford University Press, 1998 Rose G The Strategy of Preventive Medicine Oxford Medical Publications, 1992 Sackett DL, Straus S, Richardson S, Rosenberg W, Haynes RB Evidence-Based Medicine How to Practice and Teach EBM, 2nd edn London: Churchill Livingstone, 2000 Scambler G, ed Sociology as Applied to Medicine London: W.B Saunders, 1997 Townsend P, Davidson N Inequalities in Health (the Black Report) London: Penguin Books, 1982 181 PIDAPP 5/21/04 11:50 AM Page 182 Appendix Useful websites Association of Public Health Observatories Bandolier Cancer Registration Cancer Research UK Commission for Healthcare Audit and Inspection Department of Health in England Department of Statistics Health Development Agency Health Protection Agency Hospital episodes statistics Immunization in the UK National Institute of Clinical Excellence Scientific Advisory Committee on Nutrition UK National Screening Committee World Health Organization Healthy Cities 182 www.pho.org.uk www.jr2.ox.ac.uk/bandolier www.ociu.org.uk www.cancerresearchuk.org www.chai.org.uk www.doh.gov.uk www.statistics.gov.uk www.hda-online.org.uk www.hpa.org.uk www.doh.gov.uk/hes www.immunization.org.uk www.nice.org.uk www.sacn.gov.uk www.nsc.nhs.uk www.who.dk/healthy-cities PID INDEX 5/21/04 11:23 AM Page 183 Index A abortion 57–8 induced (terminations) 80, 138 following antenatal screening 138 spontaneous 79–80 Abortion Act (1967) 57 Abortion Act (1990) 57 acceptability of service 176 accessibility of service 176 screening test 138 treatment following screening 138 accidents 170–2 industrial see industry prevention 170–2 accreditation 176–7 accuracy of test 31 acid rain 130 Action on Smoking and Health 99 acute care trusts 157 adjuvants, vaccine 116 aetiology see cause age 21 death rates related to 67–8, 73–4 fertility rates related to 76–7 standardization of rates for 67–8 structure of population 71 susceptibility to infection and 104 AIDS/HIV virus 9, 104 notifications 60 screening 139 air pollution 128–30 alcohol abuse, health promotion 99–100 Alma Ata Declaration on Primary Care 151 anaphylaxis after vaccination 117 animals as models of disease as reservoirs of infection 104, 110 antenatal screening, termination following 138 antibodies passive immunization with 114–15 to vaccines 114–15 antidepressants 170 antigenic stability of pathogen 106 apothecaries 145 appropriateness of service 176 area health authorities 155 asbestos association chance, distinguishing causes and determinants from 8–10 strength of Association of Public Health Observatories 182 attributable risk, in cohort studies, calculation 11 audit 175–6 autonomy, personal, rights to 102 B Bandolier 182 barrier contraceptives and cervical cancer 42–3 BCG vaccination 15, 114, 116, 123–4 beneficence 102 Bentham, Jeremy 149 Beveridge Report 153–4 bias 84 avoidance 29–30 in cohort studies 33 in denominators 29–30 in numerator data 28–9, 66 in sampling 27–8 in screening programmes 139 systematic 30 births control methods see contraception information 53 rates 64, 76–7 illegitimate 79 seasonality and mental illness 18 stillbirths 22, 53, 56–7, 64 Births and Deaths Registration Act (1968) 53 Black Report 5, 128, 151 blinding 85 blood pressure, elevated see hypertension body mass index 63–4 Bordetella pertussis see pertussis (whooping cough) immunization breast cancer 136, 164–5 case–control study case selection 38 confounding variables 41 fluoroscopy and 36 oral contraceptives and 10 British Heart Foundation 98 British Nutrition Foundation 100 bronchial carcinoma mortalities 16 smoking and 8, 41–2 see also lung cancer buildings, hospital, expenditure 159 183 PID INDEX 5/21/04 11:23 AM Page 184 Index C Canada Lalonde Report 96 Ottawa Charter 97 Toronto, Healthy City strategy 151 cancer 163–7 breast see breast cancer cervical 42–3, 135, 166–7 colorectal 165 haematological, radiation and 131–2 lung see lung cancer registration 61 skin 167 stomach 23 testicular 165–6 Cancer Registration 182 Cancer Research UK 182 Cancer UK 98 carcinoma see specific site cardiovascular disease oral contraceptives and 78 social class and 36–7 see also heart disease case–control studies 12–13, 38–44 advantages/disadvantages 42 controls, selection 39–40 examples 42–4 risk calculation 40–1 case fatality rates 64, 65 case(s) difficulties and problems in ascertainment/identification 66 selection 38–9 cause 7–10 chance association and, distinguishing 8–10 descriptive studies in determining 14–15 of infectious disease 103–4 cause-specific rates 64 censuses 51–2 cervical cancer 42–3, 135, 166–7 Chadwick, Edwin 149 chance association, distinguishing causes and determinants from 8–10 chemical pollution of water 130–1 children accidents 170–1, 172 births see births deaths see infants; perinatal deaths immunization see immunization chlorofluorocarbons 130 cholera 10, 20, 93 deaths 75 vaccine 125 chronic disease care 149 prevention 92–3 Cities, Healthy 96–7, 151 Clean Air Act (1956) 129 climate and infection 106 clinical governance 175–6 184 clinical trials see intervention studies (clinical trials) Clostridium tetani 119 cluster allocation 46 cluster sample 27 Cochrane Collaboration 86 cohort effect 21 cohort studies 12, 32–7 advantages 33 disadvantages 33–4 examples 34–7 risk calculation 40–1 colorectal cancer 165 Commission for Health Improvement 158, 182 communicable disease see infectious disease community, continuing care in 149 community action, strengthening 97 Community Care Act (1990) 159 component vaccines 116 conception see births; contraception; fertility (rates) confounding variables adjusting for 41 definition 7–8 congenital malformations 60–1 congenital rubella syndrome 122 consent for vaccination 118 Consultant in Communicable Disease Control 59, 113 contraception 42–3, 77–8, 167 barrier, cervical cancer and 42–4 education 101 efficiency of various methods 78 oral see oral contraceptives control (in trials) and control groups in case–control studies, selection/recruitment 39–40, 42 in clinical trials, allocation to 46 coronary heart disease see heart disease, ischaemic (coronary) coroners 55 Corynebacterium diphtheriae 119 cost–benefit analysis 177 cost-effectiveness 177 costs, economic 177 NHS 159 screening 134, 138 cost–utility analysis 177 cot death 22 critical appraisal, evidence-based medicine 83–4 systematic reviews 85–6 cross-sectional surveys 25 crude rates 67 cumulative incidence 65 cycle of deprivation 128 D data 51–62 analysis descriptive studies 12 outbreaks of disease 110–11 PID INDEX 5/21/04 11:23 AM Page 185 Index capture procedure 61 grouping 63–4 numerator, errors and bias in 28–9, 66 presentation, inconsistency 25 routinely collected, problems with 25 web sources 51 see also health information; records databases, general practice 59 deaths see mortalities (rates) demands on services 174–5 demography, medical 69–81 fertility see fertility (rates) fetal loss and infant mortality 79–81 mortality, reasons for decline 74–5 populations and growth rates 70–2 transition 72–4 denominator error 66 Department of Health, responsibilities 156–7 Department of Statistics 182 deprivation, cycle of 128 derived infection 107 descriptive studies 14–23 data analysis 15–23 use of 14–15 determinants chance association and, distinguishing 8–10 descriptive studies in discovering 12 developing countries, demographics 72–4 diabetes 25 prevalence 26 diagnosis/detection criteria used, variations 24–5 diet heart disease and 168–9 promoting healthy 100 see also nutrition diphtheria 119 diphtheria/tetanus/pertussis (DTP) vaccination 117, 118–20 direct standardization 68 discreet quantitative variables 63 discrimination 30–1 disease/ill-health cause see cause distribution indices of 63–8 prevention intervention strategies 94–5 principles 93–4 see also specific diseases divorce and fertility 77 doctors/physicians history of profession 145 public health 151–2 see also general practitioners Doll, Richard 34 domiciliary health services 147, 172 double-blind trial 46 E Earth Summit 132 education see health education effectiveness cost-effectiveness 177 screening 135 efficacy definition 176 vaccines 117–18 efficiency of NHS 176 elderly accidents 172 care, local authority responsibilities 158–9 enteric infections see gastrointestinal infections environment health services concerned with 127–32 infection and 106 workplace safety 172 Environmental Health Officers 113, 150 epidemics 18–19, 107–11 common source 108 herd immunity affecting periodicity 105 investigation 109–11 propagated 108–9 types 108–9 epidemiological studies see studies/surveys equity 176 errors (in surveys) 28–31 assessment 30–1 avoidance 29 in health information 65–7 random 30 systematic 30 Escherichia coli 157 food poisoning 108, 112 ethics clinical trials 47 health promotion 101–2 screening programmes 134, 139 ethnicity 22 evidence-based medicine 82–7 challenges 86–7 critical appraisal 83–4 systematic reviews 85–6 randomized controlled trials 84–5 search strategies 82–3 strengths and weaknesses 87 exercise 100–1 expenditure on NHS 159 exposure (to agents or experience) radiation leukaemia and 36, 44, 132 lymphoma and 44 special, groups with 32–3 F family planning see contraception fertility (rates) 76–9 factors affecting 76–8 patterns, changes in 78–9 total-period 79 185 PID INDEX 5/21/04 11:23 AM Page 186 Index fetal loss see abortion financial resources see funds ‘Five a Day’ programme 100 fluoridation, water 131 fluoroscopy and breast cancer 36 folic acid supplementation, Medical Research Council Vitamin Study 50 Food and Drugs Act (1955) 113 ‘Food in Schools’ programme 100 food poisoning incidence 17 investigation 109–13 Foundation of the Manchester and Salford Sanitary Association 147 Friends of the Earth 98 funds 160 general practitioners holding 156 Primary Care Trusts and 157 sources 159 G gastrointestinal infections mortalities 75 seasonality 17 gender 21–2 susceptibility to infection and 104–5 General Household Survey 27 General Medical Council 145 general practice databases 59 General Practice Research Database 59 general practitioners fund-holding 156 history 147 services 154 see also doctors/physicians generation time 107 genetic inheritance 22 genetic screening 133 genetic susceptibility to infection 104–5 genital infections (and sexually transmitted disease) 101 cervical cancer and 166–7 notification of episodes 60 transmission 104 geographical factors in epidemiology 19–20, 109 german measles see rubella ‘Germ Theory Era’ 150 global warming 132 greenhouse effect 132 Greenpeace 98 grey literature 86 group(s) (of individuals) with special exposures 32–3 with special personal characteristics 32 test and control, allocation 46 H Haemophilus influenzae type b vaccination 118–19, 120 Hawthorne effect 28 186 health definition 51 economics see costs education see health education ill see disease/ill-health indices 63–8 inequalities 127–8, 151 targets 162–72 health authorities 153–61 local 154, 158–9 Strategic 157 Health Development Agency 98, 182 health education 96–102 alcohol abuse 99–100 contraception 77–8 definition 96 diet 100 exercise benefits 100–1 see also health information; health promotion Health Education Council 97 Health for All by the Year 2000 97, 151, 162 targets 124 health information 51–62 errors 65–7 retrieval 82–3 systematic reviews 85–6 systems 61–2 see also data; health education; health promotion; records health needs 173–4 assessment 174 ‘Health of the Nation’ Programme 100, 124, 151, 162 health promotion 96–102, 152 definition 96 ethics 101–2 new public health 96–8 programmes 98–101 sexual health 101 see also health education; health information Health Protection Agency 127, 158, 182 health services 143–52 authorities see health authorities domiciliary 147 evaluation 173–7 history and principles 143–52 personal 143, 144–5 planning 160–1 public 143–4 reorientating 97–8 see also National Health Service health workers 160–1 Healthy Cities 96–7, 151 ‘Healthy Schools’ Programme 101 heart disease, ischaemic (coronary) 168–9 mortalities 67–8 social class and 36–7 see also cardiovascular disease hepatitis A vaccine 125–6 PID INDEX 5/21/04 11:23 AM Page 187 Index hepatitis B vaccine 124 herd immunity 105 HIV infection see AIDS/HIV virus home safety 147, 172 Hospital episodes statistics 182 hospitals 145–7 episode statistics 59 expenditure 159 municipal 146 patients in, as controls in case–control studies 39 services 154 trusts 157–8 voluntary 145–6 host (human), in infectious disease as reservoirs/carriers 103–4 susceptibility 104–5 see also individual(s) housing, infection and 106 humans see host (human); individual(s) hydrocarbons, polluting 128–9 hypertension 25, 64, 137–8 Medical Research Council trial in treatment of mild 48 I illegitimate birth rates 79 illness see disease/ill-health immunity to infection 105 immunization 114–26 active see vaccination passive 114–15 routine 118–24 schedules 118 targets 124 Immunization in the UK 182 immunogenicity 106 immunoglobulins, passive immunization with 114–15 incidence (rates) 64–5 cumulative 65 incubation period 107 definition 107 Independent Inquiry into Inequalities in Health Report 128 indices of health and disease 63–8 indirect standardization 67–8 individual(s) allocation of, in clinical trials 46 autonomy, rights to 102 characteristics 20–3 preventive programmes and 95 records see records industry occupations in 60 accidents 60, 132, 172 diseases 60 risk to public of accidents 172 see also occupation inequalities in health 127–8, 151 infants death 56–7, 79–81 sudden 22, 57 health service development 147 infectious disease 103–13 antigenic stability 106 control and prevention 91–5, 103–13 see also immunization death rates from see mortalities (rates) enteric see gastrointestinal infections genital tract see genital infections (and sexually transmitted disease) host susceptibility 104–5 infectivity 106 notifiable 59, 60 outbreaks and epidemics see epidemics pathogenicity 106 public health physicians in 152 reservoirs/vehicles of infection 103–4, 110–11 transmission 104, 108 virulence 106 influenza deaths 18 vaccine 124–5 information see health information institutions, variations in incidence within single 20 intention to treat analysis 47, 84 intercensal estimates 52 International Classification of Diseases 24–5 International Conference on Health Promotion 97 Internet, data sources 51 interobserver variation 28 intervention studies (clinical trials) 13, 45–50, 84–5 allocation in 46 analysis, sequential 47 ethical issues 47 examples 48–50 follow-up 47 methods 45 outcome 46–7 ionizing radiation 131–2 IPV (Salk) vaccine 121 ischaemic heart disease see heart disease L labelling effect 139 laboratory-diagnosed infections, data 61 ‘lady almoners’ 146 Lalonde Report (Canada) 96 lead pollution 128 lead time bias in screening programmes 139 learning disabilities, local authority responsibilities 159 legionnaire’s disease length bias in screening programmes 139 leukaemia and radiation exposure 36, 44, 132 life expectancy 72–3 limb malformations, thalidomide associated 3–4 Lind, James 93 lipid-lowering therapy 87 187 PID INDEX 5/21/04 11:23 AM Page 188 Index local authority services 154, 158–9 logistic regression 41 London smog 129 Lunacy Act (1890) 146–7 lunatic asylums 146–7 lung cancer 163–4 mortalities 34–6 smoking and see smoking lymphoma and radiation exposure 44 M malaria 126 malignancy see cancer Malthus, Thomas 70 mammography 135 manpower 160–1 mass screening 135 maternal issues see mothers (in pregnancy) Maternity and Child Welfare Act (1918) 147 measles 16–17, 105, 109, 121 measles/mumps/rubella (MMR) vaccination 117, 121–3 medical audit 175–6 Medical Officers of Health 96, 150 medical profession, history 145 Medical Research Council 87 Medical Research Council treatment trial in mild hypertension 48 Medical Research Council Vitamin Study 50 Mediplus 59 melanoma 167 meningococcus vaccine 107, 123, 126 mental handicap, local authority responsibilities 159 mental health services 149, 157–8 mental illness 159, 169–70 seasonality of birth and 18 mercury pollution 130 mesothelioma 9, 94 meta-analyses 86 methyl isocyanate gas pollution 132 Midwives Act (1902) 147 migrant populations 23 morbidity statistics 64–5 source 58–61 mortalities (rates) 64–5, 71, 73–4 accidental 170–2 age-specific 73 cancer see specific site children see abortion; infants; perinatal deaths ethnicity and 22 fall/decline in 74–5 gender and 21–2 geographical variations 19–20, 21 heart disease see heart disease infectious diseases 74–5 registration data 53–6 smoking see smoking social class and 22–3 standardization see standardization of rates 188 mothers (in pregnancy) health service development 147 occupations, perinatal deaths and 44 multiphasic screening 135 multiple sclerosis 23 multistage sampling 27 multivariate analysis 41 mumps 121–2 MMR vaccine 117, 121–3 municipal hospitals 146 N National Childhood Encephalopathy Study 120 National Health Insurance Act (1911) 147 National Health Service 153–61 changes, 1970s and 1980s 155–6 cost 159 early problems 155 efficiency 176 local authorities 158–9 management 156–7 origins 153–4 planning 160–1 Primary Care Trusts 157 Strategic Health Authorities 157 National Health Service Act (1946) 148 National Health Service trusts 157–8 National Institute for Clinical Excellence 158, 182 National Screening Committee 134 National Service Framework for CHD 169 needs see health needs Neisseria meningitides vaccine 123 neonatal death, definition 56–7 see also perinatal deaths neural tube defects prevention, Medical Research Council Vitamin Study 50 neuroses 18 non-maleficence 102 North Karelia Community Trial 98 notifiable diseases 59, 60 Nuisances Removal Act (1846) 91, 149 number needed to treat 85 numerator data, errors and bias in 28–9, 66 nutrition health promotion 100 susceptibility to infection and 105 see also diet O observer variation 28–9 occupation 22–3, 25 hazards 60, 132, 172 maternal, perinatal deaths and 44 see also industry odds ratio 41 Office of National Statistics 53 operative mortality 64 opportunistic screening 135–6 ‘opportunity cost’ 177 PID INDEX 5/21/04 11:23 AM Page 189 Index oral contraceptives 101 breast cancer and 10 venous thromboembolic disease and 78 ordinal variables 63 osteoarthritis 24 Ottawa Charter 97 ‘Our Healthier Nation’ 97, 151, 163, 169, 171 ozone layer, destruction 132 P parotitis, epidemic 121–2 pathogenicity 106 ‘PE and Sports Programme’ 101 Peckham Pioneer Health Centre project 96 perinatal deaths 56–7, 79–81 maternal occupation and 44 risk factors 80–1 periodic changes in incidence 16–18 person see individual(s) personal health services 143, 148–9 history 144–5 personal skills, development 97 pertussis 119–20 pertussis (whooping cough) immunization 43–4, 119–20 DTP vaccination 117, 118–20 pharmacoepidemiology phenylketonuria screening 133, 135 phocomelia 3–4 physicians see doctors/physicians PICO 83 ‘pill scare’ 78 place (in epidemiology) 19–20 interactions with other epidemiological factors 23 planning, health service 15 pneumococcus vaccine 125 polio vaccination 116, 118, 120–1 pollution 128–32 Poor Law (1598) 144 Poor Law Commission 147 Poor Law infirmaries 146 population-dose response populations estimates, in censuses 52 growth rates 70–2 migrant 23 postcensal 52 projections 52 see also demography poverty and ill health 74, 128 pregnancy see abortion; contraception; mothers (in pregnancy) prevalence (rates) 64–5 surveys 25 prevention (of disease) primary 95 principles 93–4 secondary 95 tertiary 95 see also specific problems preventive medicine 149 primary care 148 Primary Care Trusts 156, 157, 173 primary case, definition 107 propagated epidemics 108–9 psychological disorders see mental illness public and environmental health services 127–32 Public Health Act (1848) 149–50 Public Health Act (1871) 150 Public Health Act (1875) 150 Public Health in England 152 public health services 143–4, 149–52 Q qualitative variables 63 quality framework for health care 173, 174 quality (of health care) 175 quantitative variables 63 questionnaires, reproducibility 30–1 R rabies vaccine 126 race/ethnicity 22 radiation, ionizing 131–2 radon gas 163–4 rain, acid 130 random allocation in clinical trials 45, 46, 84 random sampling 26 rates 64–5 birth see births errors in see errors (in surveys) fertility see fertility (rates) incidence see incidence (rates) mortality see mortalities (rates) prevalence see prevalence (rates) standardization 67–8 records attributes, absence of 25 unsuitable format 25 Registrar General’s Office 53 rehabilitation programmes 101 relative risk 41, 85 reliability of test result 30–1 Relief of the Poor Act 144 repeatability of test result 30–1 replication of test 30 reproducibility of test result 30–1 reproduction see contraception; fertility (rates) research in epidemiology and public health 152 Resource Allocation Working Party 155 respiratory infections, seasonality 17 retrospective studies see case–control studies rickets prevention in Asian children in Glasgow 48–9 risk 8, 11 road traffic accidents 170–2 Royal Society for the Prevention of Accidents 98 rubella 122–3 MMR vaccine 117, 121–3 vaccination 57 rural areas, mortality 20–1 189 PID INDEX 5/21/04 11:23 AM Page 190 Index S Sabin vaccine 121 Salk vaccine 121 Salmonella napoli food poisoning 110–11 Salmonella typhimurium food poisoning 108, 111 samples (and sampling) 26–8 bias 27–8 cluster 27 multistage 27 random 26 stratified 27 systematic 26–7 ‘sanitary reform movement’ 149 sanitation, infection and 106 scarlet fever 75 schizophrenia 18 Scientific Advisory Committee on Nutrition (SACN) 100, 182 screening 94–5, 133–8, 135–9 accessibility of service 138 antenatal, termination following 138 bias in programmes 139 breast 165 cervix 167 colorectal 165 cost 134, 138 criteria 136–8 effectiveness 135 ethics 134, 139 genetic 133 interval for repeat 138–9 mass 135 multiphasic 135 opportunistic 135–6 phenylketonuria 133, 135 types 135–6 search strategies, evidence-based medicine 82–3 seasonality in incidence 17–18 secondary attack rate 108 secondary care 148 secondary case, definition 107 Secretary of State for Health, responsibilities 156 secular trends, incidence 15–16 sequential analysis 47 serial interval 107 severe acute respiratory syndrome (SARS) 107 sewage disposal 131 sex see gender sexually transmitted disease see genital infections (and sexually transmitted disease) skin cancer 167 smallpox deaths 75 vaccine 75, 126, 150 smog, London 129 smoking 93, 168–9 advice to stop, clinical trial 49–50 health promotion 99 mortalities 34–6, 163 190 personal responsibility and 98 Snow, John 10, 93 Social Care Department 158–9 ‘Social Inequality and Health’ socio-economic group/social class 22–3, 128 ischaemic heart disease and 36–7 Some Department of Health in England 182 specificity (of test) 10, 31 ‘spot-maps’ 20 staff/personnel, health service 160–1 standardization of rates 21, 23, 63–8 calculation 67–8 direct 68 indirect 67–8 standardized mortality ratio 23 Staphylococcus aureus infection 134 Stillbirth (Definition) Act (1992) 56 stillbirths 22, 53, 56–7, 64 stomach cancer 23 Strategic Health Authorities 156, 157 stratified allocation 46 stratified sample 27 Streptococcus pneumoniae 125 stroke 48, 168–9 studies/surveys, epidemiological cross-sectional 25 methods, problems/limitations 24–31 sampling 26–8 types 11–13 subject see individual(s) subunit vaccines 116 sudden infant death syndrome 22, 57 suicide 169–70 sulphur dioxide pollution 128 supportive environments, creation of 97 surgeons 145 systematic reviews 85–6 systematic sampling 26–7 T targeting health status 162–72 target populations 45 tertiary care 148 test group, allocation to 46 testicular cancer 165–6 tetanus vaccination 119 DTP vaccination 117, 118–20 thalidomide 3–4, 10, 61 time (in epidemiology) 15–18 at risk/exposure to causal agent 30, 33 Toronto, Healthy City strategy 151 toxoids 114, 116 transmission (of infectious disease) 104 sexual see genital infections (and sexually transmitted disease) travellers, vaccination 125–6 tuberculosis (M tuberculosis) 94, 105, 146 BCG vaccination 15, 114, 116, 123–4 mortalities 15–16, 74 PID INDEX 5/21/04 11:23 AM Page 191 Index Type error 85 Type error 85 typhoid, vaccine 125 U UK National Screening Committee 182 urban areas, mortality 20–1 V vaccination 115–26 safety and efficacy 117–18 sites 116–17 for travellers 125–6 types 115–16 see also specific vaccines validity 31 variables 63 confounding 7–8 variation, observer 28–9 venous thrombosis Virchow’s triad virulence of pathogen 106 Vitamin Study 50 voluntary hospitals 145–6 W waste disposal 131 water pollution 130–1 weather, pollution and 129 West Nile fever 107 WHO 151 definitions, of health 50 Health for All by the Year 2000 see Health for All by the Year 2000 immunization targets 124 targets 162 whooping cough 119–20 widowhood and fertility 77 workplace see occupation World Health Organization see WHO World Health Organization Healthy Cities 182 World Wide Web, data sources 51 Y Yellow fever vaccine 126 191 PID INDEX 5/21/04 11:23 AM Page 192 ... 70 48 29 38 67 50 10 15 1 82 80 18 103 98 63 46 46 89 66 13 20 21 3 108 21 137 72 77 64 84 76 76 79 75 86 50 86 76 127 149 168 159 130 147 187 1 82 15 117 179 94 169 20 4 22 1 22 1 178 20 1 25 4 24 7 54... Buffet 12 Sept 16 14 12 10 12 Sept 12 Sept 12 Sept 12 Sept Unvaccinated Vaccinated February between infected and susceptible people which is itself influenced both by the density of population and. .. 54 159 24 6 130 76 73 76 72 73 74 75 74 29 74 73 73 0.9 1.1 0.8 1 .2 1.0 1.0 1.1 1.0 3.0* 0.7 1 .2 1.0 *c2 = 70.7; P < 0.01 They also exemplify the complementary roles of the health agencies and local