Defining and Assessing Risks to Health ASSESSING PROTECTIVE AS WELL AS HAZARDOUS FACTORS Factors that affect risk of disease or injury are, of course, not all harmful Risk factor does have a negative connotation, but ideally a risk assessment should include a range of protective as well as hazardous risk factors. For example, this report considers the protective benefits of fruit and vegetable intake and physical activity by assessing people with low levels of these factors. The important role of protective factors in adolescent health is outlined in INCLUDING PROXIMAL AND DISTAL CAUSES isks to health do not occur in isolation. The chain of events leading to an adverse health outcome includes both proximal and distal causes- proximal factors act directly or almost directly to cause disease, and distal causes are further back in the causal chain and act via a number of intermediary causes(see Figure 2.2). The factors that lead to someone developing disease on a particular day are likely to have their roots in a complex chain of environmental events that may have begun years previously, which in turn were shaped by broader socioeconomic determinants. For example, society and culture are linked to certain drinking patterns, which in turn influence outcomes such as coronary heart disease via physiological processes such as platelet aggregation. Clearly, there are risks over which an individual has at least some control (for example, inactivity) and risks that mostly or entirely rest at a population or group level(for example, ambient air pollution). It is essential that the whole of the causal chain is considered in the assessment of risks to health. Indeed many risks cannot be disentangled in order to be considered in isolation, as they act at Box 2.2 Protective factors A growing body of cross-cultural evidence indi- health behaviours(e. g, proper diet and adequate Evidence from 25 developing countries, 25 cates that various psychological, social and be- exercise, and avoiding cigarettes, drugs, excessive European countries, Canada, Israel and the havioural factors are protective of health in alcohol and risky sexual practices) are also influ- United States shows that adolescents who re- adolescence and later life. Such protection facili- enced by psychosocial factors port having a positive connection to a trusted tates resistance to disease, minimizes and delays The presence of psychosocial factors in under- adult (parent or teacher) are committed to the emergence of disabilities, and promotes standing positive human health points to new di- school, have a sense of spirituality and exhibit a more rapid recovery from illness rections for research and practice. The biological significantly lower prevalence of risky behav- Among the psychosocial factors that have mechanisms through which psychosocial and be- iours. This is in addition to being more socially been linked to protection in adults are: an opti- havioural factors influence health are a flourish- competent and showing higher self-esteem mistic outlook on life with a sense of purpose and ing area of scientific inquiry: investigations in than adolescents without such a connection. direction, effective strategies for coping with affective neuroscience are relating emotional ex- Studies in the Us have shown that these pro- challenge, perceived control over life outcomes, perience to neural structures, function, dynamics tective factors also predict positive outcomes and expressions of positive emotion Epidemio- and their health consequences. There is a need for (remaining connected to school, engaging in logical studies have shown reduced morbidity greater emphasis in policy and practice on inter- more exercise and having healthy diets) while and delayed mortality among peoplewho are so- ventions built around the growing knowledge that diminishing negative behaviour(problem drink cially integrated. The quality of social relation- psychosocial factors protect health. ing, use of marijuana and other illicit drugs, and ships in the home(parent-child relations and Adolescence is a critical life stage when life- delinquent behaviour) spousal ties) and the workplace (employer- style choices are established, induding health- Protective factors promote positive behav- mployee relations and coworker connections) related behaviours with impacts throughout life. iours and inhibit risk behaviours, hence mitigat are now recognized as key influences on physi- Recent research has begun to focus on the role of ing the impacts of exposure to risk. Current cal and mental health. A growing literature un- protective factors in youth behaviour, comple- efforts to reduce risks in the lives of adolescents derscores the protective health benefits menting previous approaches concerned only with should be broadened to include the strength ssociated with persistently positive and emo- problems and risk taking ening of protective factors. tionally rewarding social relationships. Positive Sources: (14-19)
Defining and Assessing Risks to Health 13 ASSESSING PROTECTIVE AS WELL AS HAZARDOUS FACTORS Factors that affect risk of disease or injury are, of course, not all harmful. Risk factor does have a negative connotation, but ideally a risk assessment should include a range of protective as well as hazardous risk factors. For example, this report considers the protective benefits of fruit and vegetable intake and physical activity by assessing people with low levels of these factors. The important role of protective factors in adolescent health is outlined in Box 2.2. INCLUDING PROXIMAL AND DISTAL CAUSES Risks to health do not occur in isolation. The chain of events leading to an adverse health outcome includes both proximal and distal causes – proximal factors act directly or almost directly to cause disease, and distal causes are further back in the causal chain and act via a number of intermediary causes (see Figure 2.2). The factors that lead to someone developing disease on a particular day are likely to have their roots in a complex chain of environmental events that may have begun years previously, which in turn were shaped by broader socioeconomic determinants. For example, society and culture are linked to certain drinking patterns, which in turn influence outcomes such as coronary heart disease via physiological processes such as platelet aggregation. Clearly, there are risks over which an individual has at least some control (for example, inactivity) and risks that mostly or entirely rest at a population or group level (for example, ambient air pollution). It is essential that the whole of the causal chain is considered in the assessment of risks to health. Indeed, many risks cannot be disentangled in order to be considered in isolation, as they act at Box 2.2 Protective factors A growing body of cross-cultural evidence indicates that various psychological, social and behavioural factors are protective of health in adolescence and later life. Such protection facilitates resistance to disease, minimizes and delays the emergence of disabilities, and promotes more rapid recovery from illness. Among the psychosocial factors that have been linked to protection in adults are: an optimistic outlook on life with a sense of purpose and direction, effective strategies for coping with challenge, perceived control over life outcomes, and expressions of positive emotion. Epidemiological studies have shown reduced morbidity and delayed mortality among people who are socially integrated. The quality of social relationships in the home (parent–child relations and spousal ties) and the workplace (employer– employee relations and coworker connections) are now recognized as key influences on physical and mental health. A growing literature underscores the protective health benefits associated with persistently positive and emotionally rewarding social relationships. Positive health behaviours (e.g., proper diet and adequate exercise, and avoiding cigarettes, drugs, excessive alcohol and risky sexual practices) are also influenced by psychosocial factors. The presence of psychosocial factors in understanding positive human health points to new directions for research and practice. The biological mechanisms through which psychosocial and behavioural factors influence health are a flourishing area of scientific inquiry: investigations in affective neuroscience are relating emotional experience to neural structures, function, dynamics and their health consequences. There is a need for greater emphasis in policy and practice on interventions built around the growing knowledge that psychosocial factors protect health. Adolescence is a critical life stage when lifestyle choices are established, including healthrelated behaviours with impacts throughout life. Recent research has begun to focus on the role of protective factors in youth behaviour, complementing previous approaches concerned only with problems and risk taking. Evidence from 25 developing countries, 25 European countries, Canada, Israel and the United States shows that adolescents who report having a positive connection to a trusted adult (parent or teacher) are committed to school, have a sense of spirituality and exhibit a significantly lower prevalence of risky behaviours. This is in addition to being more socially competent and showing higher self-esteem than adolescents without such a connection. Studies in the US have shown that these protective factors also predict positive outcomes (remaining connected to school, engaging in more exercise and having healthy diets) while diminishing negative behaviour (problem drinking, use of marijuana and other illicit drugs, and delinquent behaviour). Protective factors promote positive behaviours and inhibit risk behaviours, hence mitigating the impacts of exposure to risk. Current efforts to reduce risks in the lives of adolescents should be broadened to include the strengthening of protective factors. Sources: (14–19)
The World Health Report 2002 different levels, which vary over time. An appropriate range of policies can be generated only if a range of risks is assessed There are many trade-offs between assessments of proximal and distal causes. As one moves further from the direct, proximal causes of disease there can be a decrease in causal certainty and consistency, often accompanied by increasing complexity. Conversely, distal causes are likely to have amplifying effects- they can affect many different sets of proximal causes and so have the potential to make very large differences(20). In addition, many distal risks to health, such as climate change or socioeconomic disparity, cannot ppropriately be defined at the individual level. A population s health may also reflect more than a simple aggregation of the risk factor profile and health status of its individual members, being a collective characteristic and a public good that in turn affects the health status of its Research into the different levels of risks should be seen as complementary. There is considerable importance in knowing the population-level determinants of major proximal risks to health such as smoking. Similarly, there is value in knowing the mechanisms through which distal determinants operate. Understanding both proximal and distal risks requires contributions from different scientific traditions and different areas of health impact environmental, communicable, noncommunicable, injury, and so on, and as a result different intellectual tools and methods, including those of health, physical and social sciences. This in turn requires consideration of the context of particular risks: some are likely always to have negative health effects (for example, tobacco use) while others may have a role that changes from setting to setting(for example, breastfeeding protects against diarrhoeal isease, to an extent that depends on the prevalent patterns of diarrhoea). Also, the same risk can be measured and quantified at various levels depending on measurement technology Figure 2.2 Causal chains of exposure leading to disease socioeconomIc physiological Outcomes causes Causes Prevention Treatment Treatment of infectious disease can lead to prevention of further cases if it interrupts transmission. nomic causes include income, education and occupation, all of which affect levels of proximal factors such as and alcohol intake; these interact with physiological and pathophysiological causes, such pressure, cholesterol levels and glucose metabolism, to cause cardiovascular disease such as stroke or coronary heart disease. The sequelae include death and disability, such as angina or hemiplegia
14 The World Health Report 2002 different levels, which vary over time. An appropriate range of policies can be generated only if a range of risks is assessed. There are many trade-offs between assessments of proximal and distal causes. As one moves further from the direct, proximal causes of disease there can be a decrease in causal certainty and consistency, often accompanied by increasing complexity. Conversely, distal causes are likely to have amplifying effects – they can affect many different sets of proximal causes and so have the potential to make very large differences (20). In addition, many distal risks to health, such as climate change or socioeconomic disparity, cannot appropriately be defined at the individual level. A population’s health may also reflect more than a simple aggregation of the risk factor profile and health status of its individual members, being a collective characteristic and a public good that in turn affects the health status of its members (21). Research into the different levels of risks should be seen as complementary. There is considerable importance in knowing the population-level determinants of major proximal risks to health such as smoking. Similarly, there is value in knowing the mechanisms through which distal determinants operate. Understanding both proximal and distal risks requires contributions from different scientific traditions and different areas of health impact: environmental, communicable, noncommunicable, injury, and so on, and as a result different intellectual tools and methods, including those of health, physical and social sciences. This in turn requires consideration of the context of particular risks: some are likely always to have negative health effects (for example, tobacco use) while others may have a role that changes from setting to setting (for example, breastfeeding protects against diarrhoeal disease, to an extent that depends on the prevalent patterns of diarrhoea). Also, the same risk can be measured and quantified at various levels depending on measurement technology Distal socioeconomic causes Proximal causes Physiological and pathophysiological causes Outcomes Sequelae Prevention Treatmenta Figure 2.2 Causal chains of exposure leading to disease a Treatment of infectious disease can lead to prevention of further cases if it interrupts transmission. D1 P1 Pa1 O1 S1 D2 P2 Pa2 O2...n S2 D3...n P3...n Pa3...n S3...n An example: Distal socioeconomic causes include income, education and occupation, all of which affect levels of proximal factors such as inactivity, diet, tobacco use and alcohol intake; these interact with physiological and pathophysiological causes, such as blood pressure, cholesterol levels and glucose metabolism, to cause cardiovascular disease such as stroke or coronary heart disease. The sequelae include death and disability, such as angina or hemiplegia