Environmental and occupational respiratory disorders Update review ...

Environmental and occupational respiratory disorders Update review The asthma and obesity epidemics: The role played by the built environment—a public health perspective Nancy Brisbon, MD,a James Plumb, MD, MPH,a,b Rickie Brawer, MPH,a,b and Dalton Paxman, PhDc Philadelphia, Pa

Obesity and asthma have reached epidemic proportions in the United States. The reasons for these epidemics are complex, and the solutions to address them are many. This article explores the epidemics, their causes and consequences, associations and relationships, an expansion of the definition of the environment, and current national initiatives that address the components of the built and social environments that promote obesity and precipitate asthma. (J Allergy Clin Immunol 2005;115:1024-8.) Environmental and occupational respiratory disorders

Key words: Asthma, obesity, environment, built environment

Obesity and asthma have reached epidemic proportions in the United States. The reasons for these epidemics are complex, and the solutions to address them are many. With their potential associations and interactions, and with growing health care disparities, the prevention and management of obesity and asthma are increasingly focusing on collaboration between health and nonhealth professionals around public health policy, research, and advocacy related to the role played by the environment, particularly the built and social environments. Over the past several decades, the influence of direct indoor and outdoor environmental triggers on asthma have been well documented, resulting in enhancements in standards of care and changes in environmental policy. More recently, environmental policy has also been addressing the epidemic of overweight/obesity. However, to meet the challenges better of reducing the incidence and prevalence of obesity and asthma, more attention must be

From athe Department of Family Medicine, Thomas Jefferson University; bthe Office to Advance Population Health, Thomas Jefferson University Hospital; and cthe US Department of Health and Human Services, Region III, Mid-Atlantic. Disclosure of potential conflict of interest: All authors—none disclosed. Disclaimer: The views are those of the authors and do not necessarily reflect those of the US Department of Health and Human Services. Received for publication December 30, 2004; revised February 23, 2005; accepted for publication February 24, 2005. Reprint requests: James Plumb, MD, MPH, 1015 Walnut, Suite 401, Philadelphia, PA 19107. E-mail: [email protected]. 0091-6749/$30.00 Ó 2005 American Academy of Allergy, Asthma and Immunology doi:10.1016/j.jaci.2005.02.020

1024

Abbreviation used BMI: Body mass index

devoted to looking at a broader ecological model of disease prevention that emphasizes multiple levels and types of influences. Common ground for interventions to reduce the prevalence and severity of both asthma and obesity reflects an expansion of the definition of the environment. According to Srinivasen et al,1 how we think about the environment and the definition of the environment have changed over the period of the last few decades. Twenty years ago, the study of environmental health focused exclusively on chemical toxicants and their relationships to cancer and other illnesses. Now the definition of environmental health is much broader, and researchers are studying the effects on human health of the physical and social environment.1 This change is reflected in the Healthy People 2010 definition of environmental health: In its broadest sense, environmental health compromises those aspects of human health, disease and injury that are determined or influenced by factors in the environment. This includes not only the study of the direct pathological effects of various chemical, physical, and biological agents, but also the effects on health of the broad physical and social environment, which includes housing, urban development, and use and transportation, industry and agriculture.2 More comprehensive yet is Health Canada’s definition of the ‘‘built environment’’ that provides a framework for further study and analysis of environmental factors related to obesity and asthma: The built environment includes our homes, schools, workplaces, parks/recreation areas, business areas and roads. It extends overhead in the form of

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electric transmission lines, underground in the form of waste disposal sites and subway trains, and across the country in the form of highways. The built environment encompasses all buildings, spaces and products that are created or modified by people. It impacts indoor and outdoor physical environments (e.g., climatic conditions and indoor/ outdoor air quality), as well as social environments (e.g., civic participation, community capacity and investment) and subsequently our health and quality of life.3

OBESITY The latest data from the 1999 to 2002 National Health and Nutrition Examination Survey show that nearly 1/3 of all adults in the United States are classified as obese. The data show that 30% of adults 20 years of age and older—more than 60 million people—had a body mass index (BMI) of 30 or greater from 1999 to 2002, compared with 23% in 1994 and 15% from 1976 to 1980. Meanwhile, the number of children who are overweight (defined as BMI-for-age at or above the 95th percentile of the Centers for Disease Control and Prevention Growth Charts) continued to increase. Among children and teens age 6 to 19 years, 16% (more than 9 million) were overweight (BMI >95th percentile) according to the 1999 to 2002 data, or triple what the proportion was in 1980. In addition, another 15% were considered at risk of becoming overweight (a BMI-for-age between the 85th and 95th percentile). In women, overweight and obesity are higher among members of racial and ethnic minority populations than in non-Hispanic white women.4 Although there are many causes, the rise in obesity is a result in part of the progressive decline in levels of physical activity and adoption of a more sedentary lifestyle, fueled by television, computer and video games, lack of access to safe areas for physical activity, and sprawling residential neighborhoods that have increased reliance on the automobile for transportation.

FIG 1. Influence of the environment on physical activity, obesity, and asthma.

The consequences of obesity encompass health and a variety of social and economic factors affecting individuals and society. In addition to its relationship to and association with asthma, obesity leads to an increased risk of Type II diabetes, cardiovascular disease, some cancers, and osteoarthritis, as well as social stigmatization, discrimination, and poor body image, which may lead to depression. The adverse health effects of obesity have created enormous direct and indirect health care costs. According to 2002 data from the US Department of Health and Human Services, the economic costs related to obesity were estimated at more than $117 billion. A study examining the relationships of BMI in young adulthood and middle age to subsequent health care expenditure at age 65 years and older found that average annual and cumulative Medicare charges were significantly higher for individuals, both men and women, with a higher baseline BMI.5

ASTHMA The burden from asthma in the United States has also increased over the period of the past 2 decades. According to the National Center for Health Statistics (2002), 10% or 21.9 million US noninstitutional adults and 12.2% or 8.9 million noninstitutionalized children had ever been diagnosed with asthma in 2002, and in 2003, 4.2 million children had an asthma attack in the previous year.6 The prevalence of asthma in non-Hispanic blacks was 10% higher than in non-Hispanic whites and about 40% higher compared with Hispanics.7 The etiology of asthma is complex and multifactorial, and, as with obesity, environmental factors contribute to an increased risk. Risk factors for asthma include a genetic predisposition and exposure

Environmental and occupational respiratory disorders

As can be seen through these definitions and statements, attention to the environment requires the development of more far-reaching policy and environmental approaches for an effective national obesity and asthma prevention and control strategy. It has long been known that health is affected by both the design and the components of the environment. In the late 19th century in the United States, during a period of rapid urban industrial growth and significant infectious disease epidemics, public health, social work, and urban planning professionals and officials were able to collaborate successfully, halt epidemics, and affect overall health. They worked to reform housing standards, improve sanitation, and strengthen disease monitoring/ surveillance. At the beginning of the 21st century, the new epidemics are chronic illnesses, which include obesity and asthma.

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TABLE I. National initiatives addressing the social and built environment Community Preventive Services Task Forces

Active Living by Design (ALbD)

Design for Active Living

The Smart Growth Network


Project for Public Spaces

STEPS to a Healthier US

An independent, nonfederal effort studying effective community-based interventions in more than 70 target areas, including physical activity. The task forces determine the effectiveness of interventions through a systematic literature review process. Strongly recommended interventions to increase physical activity include the following: d Community-wide campaigns d School-based physical education d Social support interventions in community settings d Enhanced access to places for physical activity combined with informational outreach activities d A national program of the Robert Wood Johnson Foundation, administered by the University of North Carolina School of Public Health d ‘‘Active Living’’ is a way of life that integrates physical activity into daily routines d The goal of the ALbD program is to promote changes in design, land use, transportation and policies to cultivate active living in the context of such activity having been engineered out of daily routine d Promotes and supports research, community development, and multidisciplinary collaboration d ALbD has partnered with 25 communities around the country to put the active living concept into practice d An American Society of Landscape Architect’s theme project d A series of programs highlighting ways community design affects residents’ daily activity levels and worked with students from schools around the country to assess safe walking and biking routes between schools and homes d Formed in 1996, began when the US Environmental Protection Agency joined with several nonprofit and government organizations in response to increasing community concerns about the need for new ways to grow that boost the economy, protect the environment, and enhance quality of life d Partners include environmental groups, historic preservation organizations, professional organizations, developers, real estate interests, and local and state government entities d The Network, in its Health Focus Area, addresses the ways that community design directly affects public health d Through its work, Smart Growth is reducing health threats, particularly asthma and obesity, from exposure to pollution and indoor contaminants, improving pedestrian safety, engaging workers and residents in more active lifestyles d By promoting compact, walkable neighborhoods with mixed uses, walking and bicycling become more viable transportation options d A nonprofit organization dedicated to creating and sustaining public spaces that build communities d Provides technical assistance, education, and research through programs in parks, plazas, and central squares; building and civic architecture; transportation; and public markets d The US Department of Health and Human Services’ implementation of the President’s Healthier US initiative, which focuses on healthy choices and prevention d Promotes community initiatives, health promotion programs, state and federal policies, and cooperation among policy makers, local health agencies, and the public to invest in disease prevention d Targets obesity, diabetes, and asthma d Funds 22 grantees in 40 communities who received more than $50 million in 2003 and 2004 d Focuses on populations at risk for the target diseases on the basis of age, income, race, and insurance status d Interventions planned illustrate the range of participating organizations (eg, departments of education and health, school districts, health care providers, national and local health organizations, faith-based agencies, the private sector, and academic institutions) d Although focusing on individual interventions, the STEPS grantees also address environmental factors such as healthy food choices in schools and workplace settings, smoking in public spaces, and redesign of neighborhoods to enhance physical activity, as well as organized community interventions such as walking and biking programs d

to indoor and outdoor environmental and infectious triggers. Outdoor environmental triggers include respiratory irritant pollutants such as ground-level ozone and respirable particulate matter—both increased by the use of the automobile. A dramatic example of the relationship among automobile use, air quality, and asthma occurred during the 1996 Summer Olympics in Atlanta. The city instituted a plan to reduce automobile congestion during

the games through widespread use of public transportation. These efforts led to a 22% decline in traffic counts, a 28% decline in daily ozone concentrations, and most importantly, a 41% decline in asthma acute-care events.8 The consequences of asthma are numerous and include lost productivity, emergency department crowding, and excessive hospitalizations. Asthma is one of the leading causes of school absenteeism.

OBESITY AND ASTHMA ASSOCIATIONS The relationships, interactions, and association between obesity and asthma are complex and are active sources of hypotheses and research. Being overweight has been associated with an increased risk of new-onset asthma in boys and in children without allergy.9 Asthma is a risk for obesity in urban minority children and adolescents.10 In an extensive review (225 references) of the association between asthma and obesity, Tantisira and Weiss11 describe potential associative relationships that rely on genetics, immune system modification, and mechanical mechanisms. On the basis examination of the current evidence, they find the following: d Obesity has been associated with increases in the incidence and prevalence of asthma in several epidemiological studies of adults and children d Weight loss in obese subjects results in an improvement in overall pulmonary function and asthma symptoms, as well as decreases in asthma medication usage d Obesity may directly affect the asthma phenotype by mechanical effects including airways latching and cytokine modulation via adipose tissue, through common genes or genetic regions, or by sex-specific effects including the hormone estrogen d Obesity may also be related to asthma by genetic interactions with environmental exposures, including physical activity and diet d The Barker hypothesis, the idea that fetal programming can affect the subsequent development of chronic diseases, may underscore the developmental relationship of obesity with asthma. This programming results from a stimulus or insult at a critical sensitive period in early fetal development Recent research suggests that overweight/obesity is related to a decline in physical activity with root causes embedded in the built environment. It may likely be that programs and approaches to environmental modification leading to increased opportunities for physical activity will decrease the prevalence of obesity and may directly affect the prevalence and the severity of asthma.12

muscle latching, which leads to enhanced airways reactivity and irreversibility of obstruction. Immune modifications include TNF-a, IL-6, and C-reactive protein, all associated with the obese state. Alternatively, people with asthma may reduce physical activity, affecting obesity with further exacerbation of their asthma. Multiple authors, groups, organizations. and funders are currently addressing the built and social environment. Recent public health journals have devoted entire issues to the many dimensions of the built environment, providing a framework for prevention, intervention, research, and policy change. The September 2003 issues of the American Journal of Public Health and the American Journal of Health Promotion were focused on the built environment, health, and community design. The issues include the work of experts from diverse disciplines and highlight research related to the way communities are built and physical activity (biking/walking, traffic safety, children’s health, and air quality); and the ‘‘sense of place’’ as a public health construct. This work is leading to local changes in social policy from smoking bans to creating walks, bikeways, and community gardens and providing access to nutrition information. Nationally, several programs, interventions, and guidelines have been developed that likely will affect the obesity and asthma epidemics through study and modification of the built environment. The focus of these diverse efforts is summarized in Table I. They include the Community Preventive Services Task Force’s study of programs that have effectively led to an increase in physical activity at the population level,13 Robert Wood Johnson’s Active Living by Design Program,14,15 the Design for Active Living Program of the American Society of Landscape Architects,16 the Smart Growth Network,17 the Project for Public Spaces,18 and the US Department of Health and Human Services’ STEPS to A Healthier US program.19 In summary, obesity and asthma are inextricably linked in many complex ways. These chronic diseases continue to exact major individual and societal tolls. Significant reductions in their incidence and prevalence will require a willingness generate a concerted and coordinated effort to address the common root causes embedded in the environment we have built.

INTERVENTIONS REFERENCES

The inclusion of the built and social environment concepts in the national public health planning and local community planning processes provides a framework for review of interventions to combat obesity and asthma. Fig 1 demonstrates a model that shows the relationship/ associations between asthma, obesity, and factors in the environment. Social and built environment factors can directly affect asthma and obesity as well as opportunities for physical activity. Sedentary lifestyles have a direct relationship to obesity and may trigger genetic influences and mechanical and immune modification that affect asthma. Mechanical factors include gastroesophageal reflux and decreased tidal excursion leading to smooth

1. Srinivasen S, O’Fallon L, Dearry A. Creating healthy communities, healthy homes, healthy people: initiating a research agenda on the built environment and public health. Am J Pub Health 2003;93:1446-50. 2. Healthy people 2010: understanding and improving health. Washington DC: US Department of Health and Human Services; 2001. 3. Health Canada, Division of Childhood and Adolescence. Natural and built environments. Ottawa, Ontario, Canada: Health Canada; 2002. Available at: http://www.hc-sc.gc.ca/dca-dea/publications/healthy_dev_ partb_5_e.html. Accessed December 8, 2004. 4. Available at: http://www.cdc.gov/nchs/pressroom/04facts/obesity.htm. Accessed December 12, 2004. 5. Daviglus ML, Liu K, Yan LL, Pirzada L, Manheim L, Manning W, et al. Relation of body mass index in young adulthood and middle age to Medicare expenditures in older age. JAMA 2004;292:2743-9. 6. Available at: http://www.cdc.gov/nchs/fastats/asthma.htm. Accessed December 12, 2004.


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7. Available at: http://cdc.gov/nchs/products/pubs/pubd/hestats/asthma/asthma. htm. Accessed December 6, 2004. 8. Friedman MS, Powell K, Hutwanger L, Graham LM, Teague WG. Impact of changes in transportation and commuting behaviors during the 1996 Summer Olympic Games in Atlanta on air quality and childhood asthma. JAMA 2001;285:897-905. 9. Gilliand FD, Berhane K, Isalm T. Obesity and the risk of newly diagnosed asthma in school-age children. Am J Epidemiol 2003;158:406-15. 10. Gennuso J, Epstein LH, Paluch R, Cerny F. The relationship between asthma and obesity in urban minority children and adolescents. Arch Pediatr Adolesc Med 1998;152:1197-2000. 11. Tantisira KG, Weiss ST. Complex interactions in complex traits: asthma and obesity. Thorax 2001;56(suppl 2):64-74. 12. Redd S, Mokdad AH. Invited commentary: obesity and asthma: new perspectives, research needs, and implications for control programs. Am J Epidemiol 2002;155:198-200.

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13. Recommendations to increase physical activity. Am J Prev Med 2002;22: 67-104. 14. Available at: http://www.activelivingbydesign.org. Accessed December 6, 2004. 15. Orleans CT, Kraft K, Marx J, McGinnis JM. Why are some neighborhoods active and others not? charting a new course for research on the policy and environmental determinants of physical activity. Ann Behav Med 2003;25:77-9. 16. Available at: http://www.asla.org/lamonth/index.html. Accessed December 12, 2004. 17. Available at: http://www.smartgrowth.org/sgn/default.asp. Accessed December 7, 2004. 18. Available at: http://www.pps.org/info/aboutpps/about. Accessed December 10, 2004. 19. Available at: http://www.healthierus.gov/steps. Accessed December 9, 2004.
