Ecology And Health Research Paper

2. Emergence Of Ecological Perspectives On Health And Illness

The emergence of an ecological paradigm for understanding the determinants of health and illness in human populations can be traced to research developments in several scientific fields. During the 1920s and 1930s, a series of correlational analyses were conducted by researchers in the Chicago School of human ecology, and revealed systematic associations between community rates of illness and crime, and physical and social conditions of the urban environment including poor-quality housing and high population densities within residences and neighborhoods (cf., Faris and Dunham 1939, Park et al. 1925). These correlational studies in the fields of human ecology and sociology suggested a strong link between conditions of the urban environment and residents’ health, but did not provide an integrative theoretical account of the causal pathways connecting those variables.

An important theoretical analysis of the links between the social environment and illness etiology was provided by John Cassel in the field of public health. Cassel’s (1964) conceptualization of social epidemiology signaled a shift from ‘germ-theory’ accounts of health and illness (focusing on the health impairing effects of specific pathogens once they invaded a human ‘host’), toward a more ecologically oriented, contextual perspective emphasizing the effects of one’s social environment (e.g., work overload, sources of interpersonal stress) on immune functioning and host resistance to pathogenic agents. Cassel’s formulation of social epidemiology during the 1960s and his hypotheses concerning the impact of social and cultural factors on human health have been corroborated empirically in subsequent studies linking job strain, social isolation, and interpersonal stress to a variety of illness conditions and premature death (cf., Berkman and Syme 1979, Karasek and Theorell 1990, Marmot et al. 1997).

Publication of the US Surgeon General’s Reports in 1964 and 1979, documenting the deleterious effects of smoking on health, prompted the rapid growth of health promotion and disease prevention research during the 1980s (cf., US Public Health Service 1979). Much of the early research in this field was rooted in the concepts and methods of health education, and focused largely on behavioral change strategies aimed at fostering healthier lifestyles and health habits among individuals (cf., Belloc and Breslow 1972). Targeted efforts to enhance individuals’ health behaviors have led to reduced use of tobacco products among adults, lower rates of alcohol-related auto- mobile deaths, moderate gains in the proportion of adults exercising regularly and eating less fatty diets, and reduced employee health costs at the worksite (cf., McGinnis and Lee 1995, Pelletier 1996). At the same time, however, certain health risks, such as exposure to community violence, substance abuse, and lack of medical insurance, remain segmented in hard-to-reach ‘pockets of heightened prevalence’ (Fisher 1995)— especially among low-income and minority groups in the population (cf., Adler et al. 1994).

Growing recognition of the limitations associated with behavioral change programs has prompted a paradigm shift in the health promotion field, away from individually-focused interventions toward more comprehensive, ecological formulations that address interdependencies among socioeconomic, political, environmental, organizational, biological, and psychological determinants of health and illness (cf., Kickbush 1989, Winett et al. 1989). An explicit emphasis on ecological strategies of health promotion is evident in the design and implementation of broader-gauged community interventions aimed at reducing handgun violence, smoking prevalence, teen pregnancy, and HIV infection in recent years (cf., Breslow and Johnson 1993, Schneider Jamner and Stokols 2000). A common feature of these programs is that they incorporate multiple levels of analysis and intervention components—including political action, legislative reform, media advocacy, as well as behavioral change and environmental enhancement efforts—to address key contextual factors that substantially influence individual and population health.

One other major development that has prompted greater interest in ecology and health in recent years is the discovery of adverse global environmental changes—for instance, the depletion of atmospheric ozone and the trend toward global warming—which have the capacity to elevate population morbidity and mortality rates at worldwide as well as regional and national levels (cf., Stern et al. 1992). Potential health impacts of these global changes include elevated skin cancer rates resulting from ozone depletion and individuals’ heightened exposure to ultraviolet rays; and the food shortages, nutritional ailments, and respiratory illnesses associated with global warming (cf., Leaf 1989). The discovery of these global environmental threats to population health has prompted greater international collaboration in the development of ecologically-oriented health promotion programs through the World Health Organization’s Healthy Cities Program (cf., Duhl 1996).

3. Core Principles Of Ecology And Health Research

Research on ecology and health encompasses several disciplines, including medicine, public health, urban planning, environmental design, public policy, and the behavioral and social sciences. The scientific contours of this research are not easily delimited, due to the interdisciplinary scope of the field (cf., Stokols 2000). The unique concerns of ecology and health can be better understood in terms of the overarching conceptual principles that underlie this field, than by searching for a clearly defined body of research organized around this topic. The core principles underlying ecology and health research are drawn largely from programmatic statements about the ‘New Public Health’ and the conceptual and methodological assumptions of systems theory and social ecology (cf., Duhl 1996).

3.1 Intellectual Antecedents: Systems Theory And The Ecological Paradigm

The ‘New Public Health’ outlined in the Ottawa Charter for Health Promotion (1986) called for the development of comprehensive, ecologically-oriented approaches to the study and prevention of disease (cf., Kickbush 1989). For instance, the Ottawa Charter gave explicit attention to social causes of illness, as well as the physical-environmental health threats that exist in many communities. Subsequent analyses of ecology and health extended these programmatic ideas by providing a set of conceptual and methodological principles derived largely from systems and ecological theories, for organizing and evaluating community-based health promotion programs (cf., Green and Ottoson 1999).

The field of ecology and health incorporates a number of concepts derived from systems theory (e.g., interdependence, homeostasis, negative feedback, deviation amplification; cf., Emery and Trist 1972, Maruyama 1963) to understand the interrelations among people and their environments. Systems analyses suggest that the healthfulness of particular settings and the well-being of their participants are jointly influenced by multiple facets of the physical environment (e.g., geography, architecture, technology) and the social environment (e.g., culture, economics, politics). The health status of individuals and groups is also influenced by personal attributes such as genetic heritage, psychological dispositions, and behavioral patterns. From the vantage point of systems theory, efforts to promote well-being should be based on an understanding of the relationships among diverse environmental and personal factors, rather than on analyses that focus exclusively on environmental, biological, or behavioral factors (cf., Moos 1979).

3.1.1 Research findings From Ecological Analyses Of Health. The direct and interactive effects of environmental and personal attributes on health have been observed in several lines of research. For example, a substantial body of research highlights the ways in which poverty, inequality of income distribution, and minority status jointly undermine the health of individuals and vulnerable subgroups in the population (cf., Adler et al. 1994, Bullard 1990, Kaplan et al. 1996). Other studies indicate that neighborhood socio-economic status (percent of households in a geographic area receiving public assistance) is associated with poorer self-reports of health, above and beyond individual socioeconomic status (Malmstrom et al. 1999, Robert 1998). Interactive effects of environmental and behavioral risk factors are exemplified by the findings that environmental exposure to asbestos exacerbates chronic smokers’ risks of developing lung cancer (Grunberg 1991), and that an individual’s disposition toward exerting internal control over his her environment buffers the potentially negative effects of low education and income on health status (Lachman and Weaver 1998).

Systems theory also posits that people–environment transactions are characterized by cycles of mutual influence, whereby the physical and social features of settings directly affect occupants’ health and, concurrently, the participants in settings modify the healthfulness of their surroundings through their individual and collective actions (or, alternatively, adopt an increasingly passive stance toward their environment). For example, individuals’ routine exposure to community violence in some low-income neighborhoods can provoke feelings of disempowerment, helplessness, and depression, which in turn diminish their efforts to adopt health promotive practices related to physical activity and dietary change (cf., Sanders-Phillips 2000). Similarly, the wellbeing of elderly individuals depends on the degree of fit between their functional abilities, on the one hand, and environmental constraints on their daily activities, on the other. Either or both of these elements can be modified to promote higher levels of person–environment fit (cf., Lawton 1999).

Ecologically-oriented studies of health also incorporate certain conceptual and methodological principles drawn from the field of social ecology. For instance, ecological theory highlights the multidimensional nature of human environments. Environmental settings can be characterized in terms of their physical and social components, their objective (actual) or subjective (perceived) qualities, and their scale or immediacy to individuals and groups (proximal vs. distal). Moreover, the participants in environmental settings can be studied at varying levels ranging from individuals, small groups and/organizations, to larger communities and populations. Rather than focusing solely on individuals or aggregates, the social ecological perspective incorporates multiple levels of analysis and diverse methodologies (e.g., medical exams, questionnaires, behavioral observations, environmental recordings, epidemiologic analyses) for assessing the healthfulness of settings and the wellbeing of individuals and groups.

Social ecological analyses conceptualize human environments as complex systems in which local settings and/organizations are nested within more complex and remote regions. Accordingly, efforts to promote human well-being must take into account the interdependencies that exist among immediate and more distant environments. The occupational health and safety of workplaces at the local level, for example, are directly influenced by state and national ordinances aimed at protecting environmental quality and public health (cf., Stokols 1992).

Another core theme of ecological theory is that physiological, emotional, and social well-being are influenced by the multiple, interrelated settings that comprise the daily acti ity systems of individuals and groups (cf., Michelson 1985). Bronfenbrenner’s (1979) ecological model of human development highlights the joint influence of people’s families, school, work, and recreational settings on their health and developmental outcomes. Rather than focusing exclusively on person–environment transactions that occur within single settings (microsystems, such as home or work environment), Bronfenbrenner’s research emphasizes the ways in which functional linkages between two or more settings (i.e., the mesosystem, the exosystem, and the macrosystem) influence developmental processes and outcomes. Mesosystem units are comprised of two or more environmental settings (e.g., family and occupational environments) in which the individual is directly involved (e.g., a parent employed outside the home). Exosystems include an environment in which the developing person is directly involved (e.g., a child in his or her home environment) and one or more other settings in which that person does not participate directly (e.g., the workplaces of the child’s parents); but that, nonetheless, affect his or her development and well-being (e.g., stressful experiences at work that impair the quality of parents’ interactions with their children at home). Finally, the macrosystem level of analysis encompasses the belief systems, social norms, and institutions of the culture as a whole.

The joint influence of multiple life settings on individuals’ health has been observed in several studies. Children’s exposure to environmental stressors (such as high levels of spatial density and noise) in their home and elementary school environments, for instance, was associated with both additive and interactive effects of those conditions on their physiological health (e.g., systolic and diastolic blood pressure) and academic achievement (cf., Cohen et al. 1986). In other studies, employees’ perceived lack of flexibility in work hours for scheduling children’s doctor visits was associated with their underutilization of employer-provided family health benefits (Fielding et al. 1994). Health outcomes associated with the work–family mesosystem have also been documented through studies of the adverse impacts of ‘work–family conflict,’ as well as the positive effects of spousal support in buffering work-related stressors (cf., O’Neil and Greenberger 1994).

The research findings noted above suggest the value of studying human health from an ecological systems perspective. By considering the joint influence of multiple life settings on individuals’ well-being, a broader understanding of how personal and situational factors contribute to health status can be achieved, than by focusing more narrowly on environmental conditions within single settings.

4. Directions And Challenges Of Ecology And Health Research

The broad conceptual scope of ecology and health research is both an asset and a limitation. On the one hand, the breadth of ecological analyses affords a more comprehensive understanding of the multiple determinants of well-being. For instance, major political, economic, and environmental determinants of health that were neglected in earlier behavioral and medical studies have been targeted in more recent ecological analyses. On the other hand, so many disciplines and levels of analysis are combined in ecological research that it is difficult to achieve parsimonious explanations of health phenomena. Thus, an important challenge facing the field of ecology and health is to develop criteria for identifying the most influential determinants of wellness at particular levels of analysis (intrapersonal, social, organizational, institutional, community, global) and to give greatest priority to these high-leverage variables when designing scientific studies and community health promotion programs.

4.1 De Eloping High-Leverage Strategies For Effective Health Promotion

Examples of high-leverage variables and health promotion strategies include: (a) the implementation of strategic corporate and public policies that can enhance population health on a broad scale (e.g., California’s Proposition 99 which imposed a $0.25 tax on each pack of cigarettes sold and thereby reduced statewide levels of smoking prevalence (cf. Breslow and Johnson 1993); (b) the modification of ‘other-directed’ health behaviors enacted by corporate and public decision-makers whose actions directly influence health outcomes among large numbers of their employees and constituents; cf., Stokols (1996); (c) the identification of key life settings (e.g., a stressful commute between home and work, or poorly designed work facilities) that can be modified to reduce behavioral risk factors (e.g., smoking, substance abuse, injurious work routines) associated with poor health; (d) the implementation of defensible space design guidelines to reduce the incidence of violence and crime in urban neighborhoods (cf. Newman 1972); and (e) the development of internet-based ‘telewell-ness’ programs designed to enhance health awareness and well-being among large segments of the population (cf., Stokols 1999).

4.1.1 Targeting Ulnerable Subgroups In Health Promotion Programs. An important direction for future ecological research is to incorporate the above leveraging strategies into the design of community health promotion programs aimed at improving the wellbeing of impoverished and underrepresented groups. Certain illness risk factors, including environmental racism, exposure to community violence, and lack of medical insurance, have proven to be highly resistant to earlier and more traditional health promotion programs (cf., Bullard 1990, Fisher 1995). These interrelated community problems, borne disproportionately by low-income minority groups in the population, are highly complex and will be reversed only through the design and implementation of strategically leveraged, multilevel intervention programs (Winett et al. 1989)—example, the multisectoral Healthy Cities Programs sponsored by the World Health Organization (cf., Duhl 1996).

5. Conclusions

The field of ecology and health, which grew rapidly during the 1980s and 1990s, highlights the importance of developing integrative, broad-gauged strategies for promoting human wellness. As proponents of ecological analyses have noted aptly, improvements in individuals’ health practices ‘usually require some combination of educational, organizational, economic, and environmental interventions in support of change in both behavior and conditions of living’ (Green et al. 1997, p. 125). The principles of systems theory and social ecology outlined earlier provide a useful framework for establishing more integrative and effective approaches to wellness promotion in the coming decades.

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