Urban Health and Society: Interdisciplinary Approaches to Research and Practice - Part 9 ppt

For example, in a discussion on housing condipopula-tions and health, Saegert and Evans 25 described the powerful infl uence of housing location and its determinants in shaping the multi

Notes 61

46 Williams, D R., and Collins, C Racial residential segregation: A fundamental

cause of racial disparities in health Public Health Reports, 116 (2001): 404 – 416

47 Israel, B A., Schulz, A J., Parker, E A., and Becker, A B Review of community

based research: Assessing partnership approaches to improve public health Annual

Review of Public Health, 19 (1998): 173 – 202

48 Barnes, S L The Cost of Being Poor: A Comparative Study of Life in Poor

Urban Neighborhoods in Gary, Indiana Albany: State University of New York

Press, 2005

49 Aylott, R., and Mitchell, V An exploratory study of grocery shopping stressors

British Food Journal, 101 (1999): 683 – 700

50 Glanz, K., Sallis, J F., Saelens B E., and Frank, L D Nutrition environment

measures survey in stores (NEMS - S): Development and evaluation American

Journal of Preventive Medicine, 32 (2007): 282 – 289

51 Glanz, K., and Yaroch, A L Strategies for increasing fruit and vegetable intake

in grocery stores and communities: Policy, pricing, and environmental change

Preventive Medicine, 39, Suppl 2 (2004): S75 – 80

52 Cummins, S., Petticrew, M., Higgins, C., Findlay, A., and Sparks L Large scale

food retailing as an intervention for diet and health: Quasi - experimental

evalua-tion of a natural experiment Journal of Epidemiology and Community Health, 59

(2005): 1035 – 1040

53 Wrigley, N., Warm, D., and Margetts, B Deprivation, diet and food retail access:

Findings from the Leeds “ food deserts ” study Environment and Planning A, 35

(2003): 151 – 188

C H A P T E R

4

AN ECOLOGICAL MODEL OF URBAN CHILD HEALTH

KIM T FERGUSON, PILYOUNG KIM, JAMES R DUNN, GARY W EVANS

LEARNING OBJECTIVES

■ Defi ne the term ecological model and explain its utility in interdisciplinary research

in urban health

■ Describe key infl uences on the health of urban children at various levels of social

organization (e.g., individual, family, community, policy)

■ Describe some of the ways that researchers have studied these infl uences on child

health across multiple levels

■ Identify questions on the health of urban children that require ecological research

approaches to answer

64 An Ecological Model of Urban Child Health

INTRODUCTION

Approximately 10 million children under the age of fi ve, including 4 million infants

under the age of one month, die every year from causes that are largely preventable, 1 – 3

including preventable and/or treatable diseases such as diarrheal dehydration, acute

respiratory infection, measles, malaria, and HIV 1 , 2 In fact, three of the fi ve most

signifi cant contributors to the global burden of disease are primarily or exclusively

childhood diseases — namely, perinatal conditions, lower respiratory infections, and

diarrheal diseases 1 , 2 In addition, malnutrition contributes to over a third of all child

deaths worldwide 2 , 4 Although children living in rural areas are almost twice as likely to

be malnourished as children living in urban areas, 2 and child mortality rates are typically

higher in rural areas, 1 high morbidity, mortality, and malnutrition rates are nevertheless

serious concerns for urban children worldwide, especially in the developing world

Furthermore, there is some evidence that, with increasing rates of rural - urban migration

and the resulting growth of the urban poor, this urban advantage is decreasing and may

not exist when socioeconomic status is controlled for 5 – 7

Urbanization has been on the incline since the Industrial Revolution, with 46 percent

of the world ’ s population living in cities in 2000 as opposed to just 5 p ercent at the

beginning of the nineteenth century 8 , 9 This trend is expected to continue, and in fact,

global population growth in the next thirty years will be primarily in cities, with

approx-imately two - thirds of the world ’ s population living in cities by 2040 9 , 10

Children may be disproportionately affected by the environmental challenges inherent in poor urban neighborhoods 11 – 13 Child illnesses and malnutrition infl uence

various aspects of child development, including cognitive development and

intellec-tual performance 14 – 24 Further, child mental and physical health predict later health

during adolescence and adulthood 22 , 23 Thus, healthy children grow up to be healthy

adults 22 It is therefore critical that public health researchers and practitioners consider

the specifi c factors affecting the health of urban children in developing intervention

strategies for improving global health and development In this chapter, we suggest a

conceptual framework wherein the complex interrelations among biological,

psycho-social, and physical factors infl uencing child health in urban environments can be

studied

AN ECOLOGICAL MODEL

Ecological contexts have long been recognized as infl uential in determining

popula-tion health For example, in a discussion on housing condipopula-tions and health, Saegert

and Evans 25 described the powerful infl uence of housing location and its determinants

in shaping the multiple social and physical risks low - income and minority urban

fami-lies face

Although some research on urban public health has adopted an ecological per-spective, individual studies tend to assess the infl uences of very specifi c ecological

contexts at only one level (e.g., housing and health, neighborhood poverty and crime)

Bronfenbrenner’s Bioecological Model 65

By contrast, in its World Health Report for 2005, the World Health Organization

suggests taking an integrated rather than an isolated approach in developing both

assessments of and interventions to improve child health 26 Indeed, considerable

research indicates that health interventions are most effective when implemented at

multiple levels 27 – 33 Thus, this chapter calls for an integrated ecological approach to the

study of urban public health, employing Bronfenbrenner ’ s bioecological model to

assess the infl uences of the ecological context at multiple levels over time on child

health We use this theoretical framework as a heuristic to examine what is known and

what needs to be looked at further among the multiple, intersecting ecological niches

cities provide for children and their families, with a specifi c focus on how such

com-plex urban contexts infl uence children ’ s health We then lay out an agenda for future

work in light of the Bronfenbrenner bioecological model

BRONFENBRENNER ’ S BIOECOLOGICAL MODEL

Bronfenbrenner originally conceptualized his bioecological model as a framework for

studying development within the actual environments in which people live 34 – 40

There-fore, this framework lends itself well to the study of urban health within an ecological

framework, which necessarily emphasizes the interaction between characte ristics of the

person and characteristics of the environment in determining specifi c health outcomes 29

Further, in contrast to other ecological models employed in urban health research, in the

formulation of their bioecological framework, Bronfenbrenner and colleagues have

spe-cifi cally identifi ed some of the characteristics of the person and the environment that

have an impact on development They have further specifi ed mechanisms through which

interactions between person and environment characteristics may infl uence

develop-ment and health

Process - Person - Context - Time

Within Bronfenbrenner ’ s bioecological model are four interacting dimensions that

should be considered when studying development in context — namely, process, person,

the model, and it encompasses exchanges of energy between an organism and the

envi-ronment that operate over time 37 , 39 , 40 These enduring forms of progressively more

complex reciprocal interactions between active and evolving human organisms and the

persons, objects, and symbols in their immediate external environments, termed

this chapter, proximal processes can be thought of as two - way interactions between the

child and the objects and people in his or her immediate environment that may infl

u-ence health (see Figure 4.1 ) A simple example would be the ways a child learns to

communicate to her parent whether she is ill and needs medical treatment, while at the

same time the parent learns to identify the child ’ s need for medical treatment from her

behavior

Time (Chronosystem)

Macrosystem Exosystem Microsystem

Bronfenbrenner’s Bioecological Model 67

The power of proximal processes in directing development is posited to vary as a

function of various characteristics of the developing person, including behavioral

dis-positions, resources, and demand characteristics 40 The distinction between these

different types of person characteristics as conceptualized in Bronfenbrenner ’ s model

is not essential for our present purposes What is important to note is that much research

evidence indicates that various characteristics of the developing person do indeed shape

both mental and physical health For example, self motivation, self effi cacy, and self

esteem all positively infl uence health and well - being 41 , 42 Some evidence suggests that

the aggressiveness of physicians ’ treatments for persons suffering from heart attacks

varies by gender, whereby physicians treat males more aggressively than females 43

Another defi ning property of Bronfenbrenner ’ s bioecological model is time, which

is characterized at three different levels — namely, microtime (continuity vs

discontinu-ity within episodes of proximal processes), mesotime (the periodicdiscontinu-ity of these episodes

of proximal processes across longer time intervals such as days or weeks), and macrotime

(changing expectations and events in the larger society that may infl uence individual

development) 40 As with the specifi c aspects of the person as conceptualized in the

Bronfenbrenner model, the different levels of time are not a critical consideration for

our present purposes However, given the importance of enduring reciprocal

interac-tions between persons and their environment in directing development, we can see that

the regularity and predictability of events across time directly infl uences children ’ s

development, including their health For example, children living in families with

greater turmoil (e.g., frequent arguments between parents and parental divorce or

sepa-ration) have elevated cardiovascular activity 44 , 45 Further, the regularity of events and

levels of unpredictability and confusion in the home are related to children ’ s mental

health, independent of socioeconomic status (SES) 46 – 48

Finally, in terms of the ecological context, Bronfenbrenner and colleagues have

argued that development occurs within four nested and interacting systems — namely

the microsystem, the mesosystem, the exosystem, and the macrosystem (see Figure 4.2 ) 40

All four systems are important for understanding children ’ s health in urban

environ-ments The microsystem consists of the settings directly experienced by the child (e.g.,

the family, the peer group, the school, and the immediate neighborhood) The

meso-system consists of connections between these micromeso-systems (e.g., the interaction

between parents ’ expectations of the child in terms of nonrisky health behavior and the

expectations of the child ’ s peers) The exosystem is comprised of linkages and

pro-cesses between settings that do not contain but directly infl uence the child (e.g.,

parental work settings, the larger neighborhood) The macrosystem is the overarching

pattern of micro - , meso - , and exosystems that is characteristic of a given culture or

subculture Thus, the ecological context infl uences the critical proximal processes that

underlie human development at multiple levels In the present chapter, we focus on

how both physical and social environmental factors at these different levels infl uence

child health

68 An Ecological Model of Urban Child Health

INFLUENCES ON CHILDREN ’ S HEALTH IN THE URBAN CONTEXT

We turn now to a brief discussion of some of the key factors having an impact on urban

children ’ s health It should be emphasized that our purpose here is not to provide a

comprehensive overview of the current literature on urban children ’ s health but instead

to consider some ways this literature could be understood, and future research could

be conducted, within an ecological framework Thus, we have identifi ed key factors of

the physical and social environment that have demonstrated impacts on children ’ s

health at each level of the child ’ s environment, from her immediate surroundings to

the larger culture in which she is embedded Some of these factors have been identifi ed

by public health researchers as “ leverage points ” — individual and environmental

fac-tors that have the most signifi cant impact on a given health outcome 29 , 31 Understanding

the impact of such critical factors on child health is an essential fi rst step in developing

appropriate intervention strategies at multiple levels

Macrosystem

Physical and Social Environment: Urban Environments The macrosystem is the

overarching pattern of micro - , meso - , and exosystem factors characteristic of a given

culture or subculture 40 Urban environments can be seen as a macrosystem that leads to

FIGURE 4.2 Bronfenbrenner’s Bioecological Model: Context

Macrosystem

Attitudes and ideologies

of the culture

Extended family

Friends of family

Parents‘

work

Child

Housing

Peers Health

services

School

Neighbors

Mass media

Social welfare services

Family

Play-ground

Exosystem

Mesosystem

Microsystem

Infl uences on Children’s Health in the Urban Context 69

specifi c micro - , meso - , and exosystem characteristics, as well as to certain proximal

processes acting over time For example, three hallmark characteristics of urban

envi-ronments — namely, complexity, diversity, and density — were introduced in the

introductory chapter of this volume These characteristics operate at multiple levels of

the urban environment (including at the immediate level of the family and at the more

external level of parents ’ work environments) and infl uence practices and beliefs of

parents and their children, thus affecting child health in a unique way (Figure 4.3 )

These characteristics are briefl y considered here in light of their possible role in the

health of urban children We also discuss how these factors fi t within Bronfenbrenner ’ s

ecological model

C omplexity is one of the defi ning characteristics of an urban environment 49 Two dimensions of complexity in cities are the heterogeneity of urban populations

(micro-system) and neighborhoods (microsystem and exo(micro-system), 33 , 49 – 51 both encompassed

within the overall characteristic of diversity, and the heterogeneity of both housing

(microsystem) and neighborhood (exosystem) density 52 This heterogeneity is partly a

result of the high immigration rates that are typical of cities Further, cities change over

time, a characteristic important to consider in assessing the most critical factors infl

u-encing urban child health, which may well change as cities evolve 49 Some of this high

rate of change over time is partly due to the high mobility and residential turnover that

Parents‘

work environments

Parents

Child

Immediate neighborhood

Greater neighborhood

Environmental chaos

Exosystem

Mesosystem

Microsystem

FIGURE 4.3 The Urban Environment as a Macrosystem

70 An Ecological Model of Urban Child Health

are typical of urban environments, which result in disruptions in the child ’ s immediate

environment (microsystem) as well as in environments not immediately affecting the

child, such as parents ’ work environments (exosystem)

These dimensions of complexity render urban environments particularly challenging

to study in terms of identifying the various factors infl uencing health The development

and application of multilevel, multidimensional models in studying urban health is thus

of critical importance 27 – 33 , 49

Diversity exists both between and within cities Between different cities in

differ-ent parts of the world, differdiffer-ent characteristics of the physical and social environmdiffer-ent

may be more or less salient and may infl uence health in different ways 49 For example,

the lack of safe water and poor sanitation critically infl uence urban child health

in the developing world, 11 , 13 factors that may be less critically important infl uences in

the developed world These can be conceptualized as factors operating at the level

of the macrosystem, as they differ between large, complex environments By contrast,

overcrowding and other factors characteristic of poor quality housing in urban areas

have a direct impact on child mental and physical health in both developing and

developed cities 11 , 25 , 46 , 50 , 53 , 54 They can thus be considered components of the child ’ s

microsystem These differences require researchers to be cautious in making

genera-lizations about the critical infl uences of urban living on health in urban environments

It is also essential that differences between different children ’ s experiences be

consid-ered at the level at which they operate

Within cities, diversity encompasses the heterogeneity of both urban populations and neighborhoods and housing quality and type 33 , 49 – 51 Urban populations are

hetero-geneous along the dimensions of ethnicity, income, and socioprofessional status, among

other factors 33 , 49 As we will discuss in some detail later, characteristics such as SES

critically infl uence child health and operate both in the microsystem (e.g., within

fami-lies, schools, and immediate neighborhoods) and the exosystem (e.g., the larger

neighborhood) 55 – 56 Differing neighborhood characteristics are similarly correlated

with differential child mental and physical health outcomes, again as detailed later in

this chapter 11 , 46 , 50 , 51 , 53 , 54

Yet another level of complication in assessing the infl uences of various ecological factors on child health in urban environments is the fact that person and neighborhood

characteristics are often interrelated; for example, neighborhood segregation tends to

occur along ethnic and socioeconomic lines 25 , 50 We thus discuss SES as operating

across levels in the following section Further, both housing and neighborhood density

are heterogeneous within cities such that low - income, minority families are more

likely to live in homes and neighborhoods characterized by residential crowding 52

Thus, poor, ethnic minority urban children are exposed to considerably more

environ-mental and psychosocial stressors related to poverty than are suburban white children;

these stressors in turn infl uence child health at multiple levels 15 , 52 , 55 , 56

In many urban areas, inequality is pervasive; low - income residents, including children, lack access to adequate health and social services, which typically operate at