Basic Concepts in Prevention and Health Promotion
After completing this chapter, the reader will be able to:
- Discuss the concept of life course and the natural history of disease, particularly with respect to possible public health and clinical interventions (MCC objective 78-1)
- Understand the four levels of prevention (primordial, primary, secondary, and tertiary) (78-3)
- Describe the main functions of public health related to population health assessment, health surveillance, disease and injury prevention, health promotion and health protection (78-4)
- Describe strategies for community needs assessments (78-3)
- Appreciate the role that physicians can play in promoting health and preventing diseases at the individual and community level, including immunization, smoking cessation, cancer screening, etc. (78-3)
- Describe the five strategies of health promotion as defined in the Ottawa Charter and apply them to relevant situations (78-3).
Link these topics to the Medical Council exam objectives, especially section 78-3.
|Note: The colored boxes contain optional additional information; click on the box open it and to close it again.
Words in CAPITALS are defined in the Glossary
Chapters 1 and 2 introduced the NATURAL HISTORY of a disease, from its causal origins through to final outcomes. Understanding the characteristic natural history of a disease enables physicians to anticipate the patient’s prognosis and to identify opportunities for prevention and control.1 Based on his knowledge of Type 2 diabetes, Dr. Rao knows that Catherine Richards could face visual impairment, kidney failure, even possible amputation, if she does not manage her disease. The natural history also suggests the time frame within which he has to intervene to improve the CLINICAL COURSE of her diabetes and avoid serious complications.
Ideally, prevention occurs before people contract a disease, so preventive programs are often delivered to currently healthy people in the general population. But how early in the natural history should we intervene? Chapter 2 distinguished between upstream and downstream approaches, while the metaphor of the “iceberg of disease” reminds us that for every case seen by a clinician, there are likely to be many more people with pre-clinical disease in the community, and even more with risk factors for the condition. For some conditions (water-borne parasitic diseases, respiratory disease due to air pollution) virtually everyone in the population is susceptible, so prevention can justifiably target the entire population. For other conditions (e.g., breast cancer) identifiable groups are at higher risk, so prevention can target those. To design such a programme we must, therefore, understand the distribution of the condition in the population and know how to identify future cases.
As an introduction, Figure 4.1 links the phases in the natural history and clinical course of a disease to preventive strategies, or the “stages of prevention”. The diagram shows preventive actions (red boxes) in four stages, although in reality the stages blur one into the next. The diagram also shows how different groups of experts (in the blue boxes) will deliver the various preventive strategies in different locations.
Primordial prevention consists of actions to modify population health determinants and to inhibit the establishment of factors (environmental, economic, social, and behavioural) known to increase the risk of future disease.2 It targets determinants at the societal level rather than modifying personal risk factors, which is the focus of primary prevention. Thus, outlawing alcohol in certain countries would represent primordial prevention, whereas a campaign against drinking and driving would illustrate primary prevention.
Other examples of primordial prevention include improving sanitation (to eliminate exposure to infectious agents), establishing healthy communities, promoting a healthy lifestyle in childhood (for example, through free school meals or early childhood development programmes), or developing green energy approaches. Starfield et al. gave more examples.3 So, in preventing Catherine Richards’s diabetes, subsidized fitness programmes at the community centre should make such activities more affordable for women like her, and could help to make exercise a norm for women in her community. Although these are population-level programmes, clinicians play a role in bringing problems to public attention and in advocating for action on health determinants.
During the early 1980s the European regional office of the World Health Organization proposed actions to improve the quality of life in cities by making the urban environment conducive to healthy living: providing recreational resources, improving transportation, enhancing the environment, and raising housing standards. Toronto was an early participant in the Healthy Cities movement.4
Primary prevention aims to prevent the onset of specific diseases via risk reduction – by altering behaviours or exposures that can lead to disease, or by enhancing resistance to the effects of a disease agent. Primary prevention aims to reduce the incidence of disease; examples include vaccination and smoking cessation. Some approaches involve active participation, as with regular tooth brushing and flossing to prevent dental caries. Other approaches are passive: adding fluoride to the municipal drinking water to harden tooth enamel and prevent caries. Primary prevention commonly targets specific agents and the risk factors for particular diseases. But it may also aim to promote healthy behaviours, improve host resistance, and foster safe environments that reduce the risk of disease in general, for instance thorough cleaning of operating rooms to prevent post-operative infection. Primary prevention can tackle any of the agent-host-environment causal influences introduced in Chapter 2.
Secondary prevention includes procedures to detect and arrest pre-clinical pathological changes and thereby control the progression of a disease. Screening procedures (such as mammography to detect early stage breast cancer) are often the first step, leading to early interventions that are more cost-effective than intervening once symptoms appear. Routine blood sugar testing for people over 40 would be an example relevant to detecting Catherine’s diabetes early. Screening is usually undertaken by health professionals, either in individual doctor-patient encounters as with routine blood pressure checks, or via public health screening programs (e.g., population mammography screening programmes). The procedures for implementing a screening programme are described in Chapter 9.
Once a disease has developed and has been treated in its acute clinical phase, tertiary prevention seeks to soften the impact of the disease on the patient’s function, longevity, and quality of life. Tertiary prevention approaches are often similar to primary, but they target patients, rather than healthy people. Examples include modifying behavioural risk factors, such as assisting a cardiac patient to lose weight, or making environmental modifications to reduce an asthmatic patient’s exposure to allergens. For Catherine Richards, this might include regular check-ups to monitor her condition, including checks for possible adverse outcomes of her diabetes. The key goal for tertiary prevention is to maintain quality of life. Where a condition is not reversible, tertiary prevention focuses on rehabilitation, assisting the patient to accommodate to his disability. For reversible conditions, such as many types of heart disease, tertiary prevention will reduce the population prevalence, whereas for incurable conditions it may actually increase prevalence if it prolongs survival.
|Counselling on healthy lifestyles: dietary counselling for people at risk of colorectal cancer, etc.
|Hemoccult stool testing to detect colorectal cancer early
|Follow-up exams to identify recurrence or metastatic disease: physical examination, liver enzyme tests, chest x-rays, etc.
|Publicity campaigns alerting the public to the benefits of lifestyle changes in preventing colorectal cancers; promotion of high fibre diets; subsidies to help people access exercise programmes; anti-smoking campaigns
|Organized colonoscopy screening programs
|Reorganizing health services to improve access to high-quality follow-up care
|Infectious diseases: hepatitis C
|Counselling on safe drug use to prevent hepatitis C virus (HCV) transmission; counselling on safer sex
|Screening for HCV infection of patients with a history of injection drug use
|HCV therapy to cure infection and prevent transmission
|Education on safer sex practices; programmes to discourage needle sharing among intravenous drug users, etc.
|Establish a universal testing system for HCV in high risk groups
|(Similar to primary prevention); ensuring close control of high risk sites such as tattoo parlours that have been associated with outbreaks
|Nutrition and exercise counselling
|Screening for diabetes
|Referral to cardiac rehabilitation clinics
|Build environments conducive to active transport (walking or bicycling rather than using a car)
|Community level weight loss and exercise programs to control metabolic syndrome
|Implementation of multidisciplinary clinics
Beware: you may see the term secondary prevention mistakenly used in reference (for example) to preventing a second stroke in a patient who has had a first one. Not correct: this would be tertiary prevention, in terms of preventing further damage to the patient’s vascular system.
A body in the river
A passer-by sees a body floating down a river and calls 911. Firemen arrive and haul the person out. Paramedics start resuscitation and rush the victim to the ER; later the hospital public relations office announces that while everything possible was done to save the victim, sadly he died. Suicide is presumed.
The metaphor of intervening “upstream” or “downstream” was introduced in Chapter 2. Efforts at resuscitation (tertiary prevention) would illustrate a downstream approach, obviously open to criticism as “too little, too late.” Secondary prevention activities might focus (metaphorically) further upstream and include attempts to identify depressed people before they make a suicide attempt, perhaps by screening for depression in primary care, with possible referral to a psychologist. The modest success of such counselling, and its limited availability limit its impact on preventing suicide. Instead (or in addition), primary or primordial preventive approaches may prove more effective. They represent a transition from identifying individual solutions to population and environmental approaches. Primary prevention might include social programs for high-risk youth in areas of high suicide rates, or installing safety nets to prevent the act of suicide (which probably only moves the problem elsewhere). Primordial prevention falls in the domain of population health approaches; these involve a wide range of government agencies and focus on developing healthy public policies and altering underlying determinants of health. Approaches could include attracting small industries to town, improving youth employment training, or building leisure centres.
More on the stages of prevention
The notion of stages of prevention offers a useful introduction, but classifying a preventive action into a stage depends greatly on the context, and the stages overlap. For example, checking and then controlling blood pressure may represent primary prevention if you are trying to prevent a heart attack. But BP control may be seen as secondary prevention if the person has a family history of hypertension and you are screening for this. It may even be tertiary prevention if the patient has already had a heart attack and the goal is to prevent a recurrence. Oops – confusing!
Even more confusing: secondary prevention has been defined as slowing the progression of a disease or its sequelae at any point after its inception. From this perspective, treating a disease can be seen as prevention if it slows the progression of the disease or prevents adverse outcomes. From a public health perspective, treating an infectious disease might even qualify as primary prevention because it reduces the risk of transmitting the virus.
Conversely, excess use of antibiotics may be viewed as the opposite of prevention if it contributes to the development of resistant organisms. Clinicians should always weigh the costs and benefits of treating against those of not treating in much the same way as they do in prevention. Reflecting this theme, you may also hear the term “quaternary prevention”: where a patient is at risk of over-medication, quaternary prevention protects them from new medical invasion, promoting interventions that are ethically acceptable, and assuring quality of the care process.5
Prevention programmes may be delivered by public health agencies, by individual clinicians (frequently by general practitioners, nurses or nurse practitioners), or by community agencies (including volunteer groups such as students against drunk driving, or non-profit groups). Ideally, programmes should be coordinated between these providers; while we have many good programs in Canada, they tend to be delivered in relative isolation by the agencies responsible for them, resulting in gaps or duplication between programs. Programmes also need to be tailored to the local situation: one size does not fit all. This challenge is discussed in programme planning in Chapter 12.
HEALTH PROTECTION refers to a wide range of activities undertaken by public health departments and by government agencies such as the Public Health Agency of Canada (PHAC). Health protection spans primordial and primary prevention, and includes “food hygiene, water purification, environmental sanitation, drug safety, and other activities in which the emphasis is on actions that can be taken to eliminate as far as possible the risk of adverse consequences for health attributable to environmental hazards, unsafe or impure food, water, drugs, etc.”6 Public health protection also includes reducing environmental threats such as biological, chemical, or physical agents that could cause an epidemic if not controlled.
The law requires public health agencies to deal with specified threats that can be detected by SURVEILLANCE systems, as described in Chapter 7. The health protection approach they use will vary according to the nature of the biological, chemical, or physical risk involved. For example, federal, provincial and local inspectors work to limit the spread of communicable diseases associated with contamination of water or food. Legislation and regulations address chemical hazards, such as risks due to environmental tobacco smoke, and fines may be applied. Warning signs are often used to make hazards visible and raise public awareness. A traditional public health protection or risk reduction approach to the example of the body in the river might involve adding protective netting to the bridge. Even though nets might not deter a determined suicide attempt, they could reduce impulse suicides and would help to make the problem visible by reminding passers-by that suicides have occurred in that spot. This recognition may help indirectly, by raising vigilance in the public and encouraging people to take early warning signs seriously.
While health protection focuses on removing negative influences on health, health promotion aims to enhance health, reflecting a philosophy of supporting communities and individuals to take charge of their own health. Beginning in the 1970s and 1980s, health promotion superseded health education (which had developed pamphlets and posters, run patient education classes, etc.). This was criticized as being insufficient – see “Pamphlets may not be enough”, below. Health promotion includes, but also goes beyond, prevention: “Health promotion includes strengthening the skills of individuals to encourage healthy behaviours, and it also includes building the healthy social and physical environments to support these behaviours.”7 It involves “any combination of health education and related organizational, economic, and political interventions designed to facilitate behavioural and environmental changes conducive to health.”8
While a health promotion programme might focus on a specific issue such as smoking cessation, it would typically tackle this using a broader set of upstream interventions. These might include environmental and lifestyle changes to support non-smoking, effectively contributing to the primary prevention of disease. Applied to the body in the river, a health promotion approach could begin by asking what was causing people to throw themselves into the water, and then attempt to address this cause. It would typically focus on programs aimed at helping people to cope with life stresses, perhaps by arranging mutual-support groups.
Pamphlets may not be enough
Dr. Rao has some pamphlets alerting diabetic patients to the need for careful monitoring and control of their condition in order to avoid serious adverse outcomes. But he can see that these are no help for Catherine, given her increasing memory problems. She needs a broader support programme, involving her family members and other community resources. He encourages her son Paul and his wife Julie to get Catherine to join a diabetic support group that he plans to set up. He hopes that they can contribute by leading some physical activities that would get them actively engaged in the community, for the benefit of all.
The philosophy of health promotion
Health promotion reflects a characteristic set of values, such as self-responsibility for health, that characterize much of the WHO thinking: “Health promotion is the process of enabling people to increase control over, and to improve, their health.” This definition derived from the WHO conception of health described in Chapter 1: “The extent to which an individual or group is able to realize aspirations and to satisfy needs, and to change or cope with the environment.”8 Along with self-responsibility, other core values of health promotion include factors such as:
- Promoting equity and social justice;
- Applying a holistic definition of health;
- Considering the full range of health determinants;
- Addressing environmental influences on health;
- Empowering people and building individual and collective capacity;
- Seeking to enhance people’s social participation; and
- Fostering collaboration between agencies.
Community health promotion
Health promotion is based on the argument that health behaviours are unlikely to change in a lasting manner unless environmental factors that give rise to them are also changed. This implies mounting a campaign that focuses on environmental change and community engagement, in addition to modifying individual behaviours. Just as individuals change what they consider a priority, communities have a more or less well-articulated set of priorities that may support or inhibit efforts to promote health. An opinion survey of perceived community needs is therefore often the first stage in mounting a local health promotion campaign: what does this community perceive as its priorities and how do these match the goals of the health promotion team? Community Health Centres commonly apply a needs-based approach to planning health promotion programmes, guided by community representatives on their board of directors. Engaging community members in the planning process not only ensures that the programme is likely to be relevant to local needs, but also helps to ensure community support for the programme and participation in it. The actual design of the programme may be developed following a case conference of experts in relevant specialties who suggest approaches designed to match the particular local situation.
The principles on which community health promotion strategies are designed were described in the Ottawa Charter for Health Promotion.
In 1986, Ottawa was the venue for an international conference sponsored by the WHO to establish the basic design principles for health promotion programmes.8 The resulting charter built on a 1981 Global Strategy to achieve health for all by the year 2000.9 The charter set out a range of upstream and downstream approaches as outlined in the box below.
The Ottawa Charter for Health Promotion
The Ottawa Charter and the Health for All 2000 manifesto included the following strategies:
- Building healthy public policy. The aim is to put health on the agenda for all policymakers, and to ensure that they consider the health implications of their decisions. A healthy public policy is one that avoids the side effect of damaging health while pursuing some other goal.
- Creating supportive environments. The emphasis on environment reflects an awareness of the impact of natural, built, and social environments on health, and proposes a socio-ecological approach to health.
- Strengthening community action. Health promotion requires community empowerment and involvement in setting priorities and in planning and implementing strategies to achieve better health.
- Developing personal skills. Health promotion supports personal and social development through providing information and enhancing life skills.
- Re-orienting health services. Health promotion argues for shifting health resources towards a more equal distribution between treating disease and preventing it. Essentially, health services should be expanded to include the four strategies above in addition to conventional medical care. Responsibility for health promotion services should be shared among individuals, community groups, health professionals, health services, and governments.
The Charter also identified seven prerequisites for health: peace, shelter, education, food, income, a stable eco-system, and sustainable resources. These prerequisites are closely related to the macro-social determinants of health and are essential in understanding why we have failed to reach the goal of “Health for all by the year 2000” (HFA 2000) even though it is over 20 years past the deadline.10, 11
Discussion points: to what extent has the world failed in this goal, and why? How can a physician influence these factors in his or her practice?
A public health programme in Glasgow, Scotland undertook an experiment to improve the dental health of 5-year-old children living in deprived neighbourhoods.12 The oral health of these was among the worst in Western Europe.
A “From Birth” caries prevention programme addressed early lifestyle determinants of dental caries, and oral health action teams in each of the city’s 15 health care administrative areas led the interventions.
The activities they undertook illustrate the ideas in the Ottawa Charter:
Building healthy public policy: staff were trained in all nursery schools; healthy snacks policies were introduced in nursery schools; the programme subsidized utensils and food blenders; free fluoride toothpaste was provided
Supportive environments: they organized community oral health promotion events; facilities in nursery schools were improved; they held community consultations and arranged ‘get cooking’ classes
Developing personal skills: literature was translated into jargon-free language; they taught children tooth brushing skills; dental health song books were developed
Strengthening community action: there was a strong emphasis on engaging community members, and programme staff trained community trainers. This established networks of voluntary community activists who led outreach into the communities, engaging community groups in identifying ways to promote dental hygiene behaviours, and leading community events
Reorienting health services: the oral health action teams promoted perinatal oral health sessions in doctors’ offices, and created dental registration programmes.
The programme included an evaluative component that will be summarized in Chapter 7.
1. Distinguish between the natural history and the clinical course of a disease.
2. The Pap smear test detects cervical cancer in women at an early stage of the disease when there are no symptoms and the disease is not evident on visual examination. Which of the following statements applies to a woman with no history of cervical cancer who undergoes a Pap smear?
A. She is practising primordial prevention.
B. She is practising primary prevention.
C. She is practising secondary prevention.
D. She is practising tertiary prevention.
E. This is a screening test, not a preventive procedure.
C) Secondary Prevention
A. Primordial prevention acts early in the causal chain, to alter general social or economic circumstances that give rise to risk factors. The Pap test does not address general circumstances, but a specific disease process.
B. Primary prevention is defined as the avoidance of disease – having a Pap smear would not prevent the disease from occurring.
C. Secondary prevention is defined as the interruption of any disease process before the emergence of recognized symptoms or diagnostic findings of the disorder. The Pap smear test forms an essential step in this process: it identifies the disease process before the emergence of symptoms.
D. Tertiary prevention is defined as the avoidance of negative sequelae of a disease process, once the disease has been diagnosed and treated. The Pap smear concerns early detection; it has nothing to do with subsequent effects of the disease.
E. Yes, it is a screening test, but that forms an integral component of an approach to prevention. So this response is splitting definitional hairs and presumably the physician’s intent in administering the test was to prevent further progression of the cancer.
3. Contrast the underlying philosophies of health promotion and health protection.
Health promotion seeks to foster the capacity for self-responsibility in a community, enabling it to improve its health via collective action. Health protection is set of actions, often supported by legislation, applied by an external authority to avoid adverse health consequences. Involvement of the community may be limited.
4. Summarize the elements in the Ottawa Charter for Health Promotion
Building healthy public policy; Creating supportive environments; Strengthening community action; Developing personal skills, and Re-orienting health services.
Now give examples of how these might be put into practice in a typical family medicine centre in the area where you live.
- Bhopal RS. Concepts of epidemiology. Oxford: Oxford University Press; 2002.
- Porta M, editor. A dictionary of epidemiology. New York (NY): Oxford University Press; 2008.
- Starfield B, et al. The concept of prevention: a good idea gone astray? J Epidemiol Community Health. 2008;62:580-3.
- Beaglehole R, Bonita R, Kjellström T. Basic epidemiology. Geneva, Switzerland: WHO; 1993.
- Flynn BC. Healthy cities: toward worldwide health promotion. Annu Rev Public Health. 1996;17:299-309.
- Last JM. A dictionary of public health. New York: Oxford University Press; 2007.
- Green L. National policy on the promotion of health. Int J Health Educ. 1979;22:161-8.
- World Health Organization. Ottawa charter for health promotion. Geneva: WHO; 1986 [cited 2011 June]. Available from: http://www.euro.who.int/en/who-we-are/policy-documents/ottawa-charter-for-health-promotion,-1986.
- World Health Organization. Global strategy for health for all by the year 2000. Geneva: WHO; 1981 [cited 2015 December]. Available from: http://apps.who.int/iris/bitstream/10665/38893/1/9241800038.pdf.
- Bryant JH, Zuberi RW, Thaver IH. Alma Ata and health for all by the year 2000. The roles of academic institutions. Infec Dis Clin North Am. 1991;5(2):403-16.
- Gunning-Schepers LJ. “Health for all by the year 2000”: a mere slogan or a workable formula? Health Policy. 1986;6(3):227-37.
- Blair Y, Macpherson L, McCall D, McMahon A. Dental health of 5-year olds following community-based oral health promotion in Glasgow, UK. Int J Paediatric Dentistry. 2006;16:388-98.