Used with permission from Liebert Publications
ENVIRONMENTAL JUSTICE
Volume 2, Number 4, 2009
ª Mary Ann Liebert, Inc.
DOI: 10.1089=env.2009.0027
U.S. Childhood Obesity and Climate Change:
Moving Toward Shared Environmental Health Solutions
Perry E. Sheffield and Maida P. Galvez
ABSTRACT
This article focuses on the epidemic of childhood obesity, a significant cause of pediatric morbidity in the
United States. It begins with a review of the evidence regarding environmental influences on obesity. Then
it draws from that evidence to cite examples of climate change prevention and preparedness efforts that
could also benefit the obesity problem. Climate change is a global environmental issue predicted to negatively impact children’s health. In the United States, many regions are expected to experience worse air
quality, increased vector-borne disease, and changes in food availability. Children’s size, developmental
stage, and long life expectancy make them unique when considering health effects from the environment.
Furthermore, in the latter part of this century, the children of today will become seniors, a group also
vulnerable to predicted health impacts from climate change. These vulnerabilities will contribute to existing health disparities that are due, in part, to unequal risk factors in communities of color and low
income. Improved air quality, healthier diets, and increased physical activity are all potential results of
climate change interventions. Unintended potential negative consequences are also discussed and careful
pre-intervention assessment is emphasized. Interdisciplinary collaborations for research and solutions are
needed for large scale environmental issues such as climate change and their impact on multi-factorial
health problems including childhood obesity. Carefully selected climate change-related efforts can simultaneously address current children’s health problems, future population health concerns, and ultimately result in more equitable health for all.
NEW PEDIATRIC MORBIDITIES
W
hile childhood infectious diseases continue to
significantly burden parts of the world, they are
rapidly becoming eclipsed by the emergence of previously rare and altogether new problems referred to as the
new pediatric morbidities. These are typically chronic conditions that persist into adulthood and include obesity,
asthma, neurodevelopmental disorders like attentiondeficit and hyperactivity disorder (ADHD), childhood
cancers, birth defects, and preterm birth. The portrait of
childhood conditions in the United States is very different
Dr. Sheffield is a research fellow in the Departments of Preventive Medicine and Pediatrics at Mount Sinai School of Medicine in New York.
Dr. Galvez is an assistant professor in the Departments of
Preventive Medicine and Pediatrics at Mount Sinai School of
Medicine.
from global pediatric disease but increasingly these new
morbidities are beginning to appear around the world
due in part to changing global trends in diet, activity
levels, and air quality.2–5 Within the United States, significant disparities exist in children’s health that are related
to numerous factors including different environmental
exposures. Research shows that environmental factors
such as the built, or human-made, environment contributes to the rising prevalence of these health problems.
Whether considering the built environment or environmental toxins, children’s size, developmental stage,
and long life expectancy make them uniquely vulnerable.
Through different mechanisms in different parts of the
world, climate change is creating new environmental
risks while exaggerating old ones to which children have
increased vulnerability such as increased heat, changes in
outdoor air quality, rising sea level, and contaminated
water. Older individuals are also more vulnerable to these
changes. The children today will be seniors in the latter
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SHEFFIELD AND GALVEZ
part of this century. The effects of climate change on both
current and future environmental risks thus will impact
today’s children throughout their life span.6,7 Furthermore, climate change is exacerbating already glaring international disparities in children’s health and is thus an
environmental justice issue. Environmental justice issues
are defined here as unequal community exposures (chemical or otherwise) resulting from the actions and decisions of persons, institutions, or nations external to those
exposed communities.
Obesity and, increasingly, climate change have been at
the forefront of health concerns, with widespread coverage in scientific journals, national and international conferences, and the media. Yet opportunities for exploring
interdisciplinary approaches to addressing these health
issues have been far fewer. The purpose of this article is to
identify potential co-benefits from climate change interventions on one major U.S. pediatric morbidity, obesity.
First, evidence regarding environmental risk factors for
pediatric obesity is examined. Then, some select climate
change prevention and preparedness interventions and
their demonstrated or potential co-benefits for obesity are
described. Of note, some diseases such as asthma have a
more extensive body of research on environmental risk
factors and quantified studies of co-benefits from climate
change interventions.5,8–14 The purpose of this article is to
explore the potential crossover between climate change
interventions and pediatric obesity, an interface which
has received considerably less attention. The importance
of this approach lies in its potential ability to break ongoing cycles that perpetuate poor health outcomes and
on-going injustice.
OBESITY
Affecting over 15% of children nationally,15–18 childhood obesity is defined as having greater than 95th percentile for body mass index (BMI, weight in kilograms
divided by height in meters squared) for a child’s age.
While the national average is high, there are communities
within the United States, such as East Harlem, New York,
where more than 25% of young children are obese. Thus
the burden of this illness is not equally distributed. Additionally, in communities of color and low income, such
as East Harlem, there is also evidence of unequal chemical
and built environment exposures which are discussed in
more detail later. Lastly, there is emerging evidence regarding the relationships between these unequal exposures and the prevalence of obesity which contribute to
this as an environmental justice issue.19
In terms of the consequences of obesity, obese children
are more likely to have insulin resistance, diabetes, hypertension, cancer, gallbladder disease, liver disease,
atherosclerosis, and depression. In addition, adults who
were obese as children have increased mortality regardless of their adult weight.20 Lack of physical activity and
high calorie diets are known risk factors for obesity
among children in the U.S. Many individual factors also
influence this relationship and are more studied among
adults. Examples include co-morbid conditions and indi-
vidual perception of safety.21 The following section
reviews the evidence on environmental factors and interventions that influence physical activity levels and food
habits.
BUILT ENVIRONMENT AND OBESITY
The few existing child-focused studies have shown a
positive correlation between physical activity level and
time spent outdoors, residential proximity to recreational
facilities and parks, availability of adult supervision, improved school facilities such as basketball courts, and
housing density.22–24 Other studies have shown that increased presence of green spaces as measured by satellitederived greenness measures and geographical information
system (GIS)-based neighborhood vegetation measures
are inversely associated with children’s BMI.25,26 These
factors are considered part of the built environment. One
study found that, instead of the physical environment, a
positive social environment—higher collective efficacy,
more collective socialization of children, more social ties
among neighbors, and greater perceived neighborhood
safetywas positively associated with more activity.27
For adult studies of obesity, the body of evidence is
larger. Multiple studies have documented an association
between characteristics of adults’ neighborhoods, physical activity levels and BMI.28 Presence of specific neighborhood amenities such as walking trails, sidewalks, and
bicycle paths are associated with more adults meeting
basic recommendations for physical activity.29,30 Street
connectivity and mixed residential densities are also associated with increased physical activity.31 Studies have
further demonstrated a positive association between obesity and increased vehicle miles traveled as a result of
urban sprawl (defined as low density developments surrounding urban areas).32,33 In an Oregon study, increased
neighborhood fast-food outlets and individual unhealthy
eating behaviors were related to weight gain, while better
neighborhood walkability and increased levels of physical
activity were likely to be associated with maintaining a
healthy weight over time. In this study, walkability was
determined by a composite score that included land-use
mix, street connectivity, public transit stations, and green
and open spaces.34 As we will discuss in more detail later,
many of these built environment factors are areas of potential intervention that can impact obesity problems as
well as both the causes of and necessary adaptations to
climate change.
Environmental interventions and obesity
Despite a growing body of evidence supporting an
association between environmental factors, physical activity level, dietary quality, and obesity, research gaps
remain regarding obesity interventions specifically addressing these factors. For example, few studies demonstrate the effectiveness of community level interventions
to increase access to physical activity resources and the
subsequent impact on childhood BMI or obesity-related
health outcomes.35 One review focusing on interventions
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U.S. CHILDHOOD OBESITY AND CLIMATE CHANGE
to prevent or manage type 2 diabetes in children concluded that 60–90 minutes of daily physical activity and
less than 60 minutes of daily screen time (including video
games) were necessary but called for larger-scale studies
to determine the most effective methods of achieving
these goals.36 Cochrane reviews on treatment and prevention of obesity in children state that longer-term
studies are needed to demonstrate effectiveness and not
enough evidence has been gathered to show that one
particular program is successful at obesity prevention.
Though, most programs reviewed showed moderate increases in physical activity or improved dietary choices.37,38
The effectiveness of interventions that target entire
communities such as increased availability of fruits and
vegetables has been little studied with respect to impacts
on children’s dietary habits and subsequent risk for obesity. One study demonstrated that lower fruit and vegetable prices were associated with decreased BMI gain in
elementary school age children.39 Additionally, relatively
simple environmental interventions have positively altered children’s eating patterns. For example, after the
introduction of a salad bar in an elementary school, increased fruit and vegetable consumption correlated with
decreases in overall fat and calorie intake.40 There are
additional benefits of children having more exposure to
fresh food. The presence of school gardens are thought to
enhance academic instruction.41 And, while there is a need
for more research, there is strong theoretical support of
school gardens’ positive impact on student well-being.42
As mentioned previously, some obesity interventions
target the availability of healthy food choices on a community level. Linking food availability to health outcomes
is a multi-step process. Some of the more intermediate
links have been better examined than health outcomes.
For example, increased fruit and vegetable consumption
has been associated with the presence of at least one supermarket within the neighborhood.43 A further study
went on to demonstrate that presence of neighborhood
supermarkets is associated with less obesity in adults.44
Also importantly, some factors that put certain children at
unequal risk have been shown to exist such as inequities
in food store availability by race=ethnicity in some communities within New York City.45 As with physical activity
interventions for obesity, the evidence of the effectiveness
of dietary interventions for weight loss, especially in adolescents, is lacking.46,47 If anything, the limited evidence
of effective interventions should underscore the need for
multi-disciplinary and integrated solutions to tackle these
multi-factorial problems. With this in mind, this article
will now examine solutions that can feasibly address
more than one problem at a time.
CLIMATE-SPECIFIC SOLUTIONS
We focus now on examples of climate change interventions that have demonstrated or potential co-benefits
for childhood obesity. Climate change solutions or interventions are broadly defined here to include prevention
efforts that target greenhouse gas emissions or pre-
paredness efforts that help individuals and communities
adapt to protect human health as climate changes.
Urban planning
Many climate change initiatives included in urban
planning efforts have potential to increase physical activity levels in children. One substantial urban initiative
launched in 2007 in New York City is called PlaNYC and
includes climate change prevention and preparedness
efforts as well as many other urban planning goals. This
plan includes an open space initiative with the goal of
having every city resident within a ten-minute walk of a
park. Improved lighting on public spaces such as school
yards will extend usable hours as well as increase public
safety. Another PlaNYC program, called MillionTreesNYC, aims to plant one million trees in the city limits
within a decade. Chicago and Philadelphia have similar
programs called, respectively, the Chicago Climate Action
Plan and GreenPlan Philadelphia. A large part of these
programs are street tree initiatives which will increase
neighborhood greenness, a factor associated with increased
physical activity for children. These tree initiatives and
other adaptation measures will reduce the urban heat
island effect—a result of more dark, heat-absorbing surfaces in cities relative to suburban or rural areas—and
thus reduce the impact of recurrent and increasing heat
waves (e.g., tax incentives for lighter colored roofs and
promenades with reduced vehicular traffic).48–51
A number of urban planning initiatives including PlaNYC, Greenprint Denver of Denver, Colorado, and
GreenLA of Los Angeles, California are framed around an
expectation of an increasing urban population with goals
of maintaining high-quality living and mixed use zoning
within areas of increased housing density, other factors
associated with more physical activity. Numerous cities,
including Washington DC, have started bike share programs to encourage non-motorized transportation. A point
of criticism about some of these programs is that some
initiatives could have disproportionate negative effects on
certain communities if not implemented carefully. One example is the effort to increase public transportation use.
Projects must be carefully examined so as not to increase
traffic in peripheral, low-income neighborhoods where
there are large numbers of asthmatic children who have
increased susceptibility to the effects of air pollution. That
said, some of these incentives such as increased use of
public transport and more green space, if carefully implemented, could have positive health effects for those
same children.48,52–58
Food production
Food and agriculture are responsible for a substantial
portion (over 15% or more depending how much food
transportation is included in the calculation) of global
and U.S. greenhouse gas emissions. A disproportionate
amount of those gases come from livestock production.
Increased livestock production leads to increased demand
for animal feed which can drive up the cost of food grains
for people. Plant-based diets use much less energy than
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meat based diets—particularly those diets including meat
from ruminants like cows and sheep that produce methane, a potent greenhouse gas. The heavily meat based diet
in the United States differs from the majority of the world
who eat primarily plant-based diets out of economic necessity. These differential global diets are a cornerstone of
climate justice advocacy. Climate justice efforts emphasize that the contributions to climate change, such as the
larger per capita greenhouse gas emissions from countries
that consume large quantities of meat, are much higher
than in countries where the impacts of climate change are
expected to be the most significant.
Because plant-based diets contribute significantly less
greenhouse gases into the atmosphere than meat-based
diets, some climate change interventions advocate for
plant-based diets as a means of climate change mitigation.
One initiative, called Meatless Monday, began and is still
billed in the U.S. as a health campaign but increasingly its
merits as a climate change intervention are being touted.
This campaign seeks to encourage carnivorous individuals to decrease their meat intake by skipping meatcontaining meals one day per week.59–61 Additionally,
many communities in the U.S. have become part of an
unofficial local foods movement including farm to school
programs, farmers’ markets, and community supported
agriculture (called CSAs).62,63 As inadequate fruit and
vegetable intake contributes to the childhood obesity epidemic, the promotion of plant-based diets thus has a dual
role in addressing both obesity and climate change.
The previous examples focus on changing consumer
demand. Climate change initiatives can also affect dietary
habits in the form of incentives and policies for farmers. In
1999, member countries of the Organization for Economic
SHEFFIELD AND GALVEZ
Co-Operation and Development provided substantial
subsidies—close to $300 billion—to support agricultural
production. The orientation of these funds can substantially alter farming practices. The United States’ Conservation Reserve Program pays for land to be taken out
of production for certain periods of time, a practice that is
known to rejuvenate soil and decrease need for fertilizers.64 In addition to providing positive financial incentives, the government may also penalize climate-harmful
practices. Penalties include taxes on fertilizers or pesticides which use fossil fuels in production and removal of
subsidies that do not promote ecological health. The
Kyoto Protocol, a measure to set international limits on
greenhouse gas emissions, is one example of both the
complexity and importance of international policies due
to the global nature of pollution and climate change.65 As
long as the U.S. continues to rely on fossil fuels for fueling
farm production and producing pesticides, significant
benefits may be seen by reducing the energy demand of
food production. Some effects could be lower coal plant
emissions and less diesel vehicle emissions. No studies
were found that specifically quantify pediatric health
benefits from interventions targeting these factors but the
supporting theory is strong. Figure 1 summarizes the
multiple levels on which these interventions work.
PRECAUTIONARY APPROACHES
Regardless of the potential effects of any climate
change or pediatric obesity intervention, thorough assessments are warranted prior to implementation of largescale projects to try to determine who will benefit or be
harmed and when and where that benefit or harm will
FIG. 1. Examples of community level climate change interventions with variable potential impacts on childhood
obesity at the level of the child, family, and school=community.48–51,60,63 Adapted from Ecological Systems Theory
model.66
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U.S. CHILDHOOD OBESITY AND CLIMATE CHANGE
occur. Increasing physical activity is one significant arm
of the environmental interventions regarding obesity and
increased human-powered transportation is a central
theme of many climate change interventions. Within both
types of intervention, safety during that physical activity
is of significant concern. Unintentional injury, though not
considered a new pediatric morbidity, is the leading cause
of death for children.67 While the majority of the unintentional injuries are due to motor vehicle crashes, a study
in Baltimore, documented increased pedestrianvehicular crashes near schools that had more features that
increased pedestrian demand.68,69 Projects such as Safe
Routes to School are planning efforts to try to reduce
additional accidental injuries while helping to increase
physical activity.68 As increased walking and bicycle
riding are encouraged it is essential that safety precautions (such as helmets, sidewalks with adult supervision,
and play spaces that are isolated from vehicular traffic) be
used to prevent an increase in morbidity or mortality
associated with these activities. Any climate change intervention should be explored for its potential to reduce
injury risk factors or at a minimum safeguard against
their increase.
While any intervention should try to minimize negative
health consequences, at times, climate change interventions could have simultaneous positive and negative effects on pediatric morbidities. Take for example urban
greening efforts which encourage outdoor time and indirectly increase physical activity. While vegetation can
improve air quality, the intervention could result in
greater exposure to existing outdoor air pollution and
worsening of symptoms for asthmatics. In these situations, additional efforts are needed such as education
about how to monitor air quality. Information is publically available on the AIRNow web site which alerts
asthmatics to avoid outdoor activity when levels of some
air pollutants pose an increased risk.70 The counterargument to avoiding outdoor air pollution is that indoor
air pollution has numerous known potentially modifiable
risk factors such as cigarette smoke, mold, cleaning
product vapors, and pesticides so education needs to
address both indoor and outdoor risks in order not to
present too biased a picture. This scenario is not the only
way asthma and obesity are potentially related. Numerous studies have identified an association of asthma with
obesity. The causal direction of this relationship has not
been well established but weight loss has been shown to
decrease the severity of asthma.71,72 This relationship
represents an additional area of potential benefit and
caution.
The challenges of climate change intervention assessments are daunting for even seasoned health and other
risk assessment professionals. Even more difficult is
communicating this information to individuals without
specialized training in the relevant fields. This additional
challenge is being addressed by the growing fields of risk
communication and environmental health literacy.73,74
For pediatric health issues, a national network called the
Pediatric Environmental Health Specialty Units, staffed
by trained physicians, fields questions regarding the
particular complexities of pediatric environmental health.
The National Children’s Study which began enrollment in
2009 in the U.S. will build the knowledge base on which
pediatric environmental health professionals and others
rely to inform pre-intervention assessments, improve risk
communication strategies, and enhance environmental
health literacy.75
CONCLUSION
This article highlights the unintended consequences of
climate change interventions that could have positive
health effects on childhood obesity while at the same time
including precautionary advice about potential unintended negative effects of certain interventions. Both
types, positive and negative, are important to include in
the program planning or resource allocation effort and
would provide a helpful contribution to any cost-benefit
analysis or intervention comparison. Clearly, the piecemeal approach of this article and reliance on theoretical
effects demonstrates that further studies are needed to
assess which programs have greatest health benefits.
Many climate change interventions are costly and justification depends often on a multidisciplinary assessment.
Sometimes accounting for health benefits alone is not
enough to demonstrate cost effectiveness. In one study,
the cost of installing a light rail in a North Carolina city
was calculated to be larger than the public health benefits
over a nine-year period leading the authors to conclude
that additional—perhaps ecological, commercial, and social capital—benefits need to be figured into the analysis
as well to be convincing economically and thus requires
engaging…
Article Summary: After reading the article U.S. Childhood Obesity and Climate Change: Moving Toward Shared Environmental Health Solutions located in Doc Sharing, write a paper summarizing, agreeing, disagreeing, responding to, or reflecting your personal thoughts and observations about the article. The paper must be double spaced, minimum two-pages in length, and in APA format.
