Adolescent Obesity: Towards Evidence-Based Policy and Environmental Solutions
2009; Elsevier BV; Volume: 45; Issue: 3 Linguagem: Inglês
10.1016/j.jadohealth.2009.06.022
ISSN1879-1972
AutoresMary Story, James F. Sallis, C. Tracy Orleans,
Tópico(s)Health and Lifestyle Studies
ResumoAdolescent obesity is one of the major global health challenges of the 21st century. In the United States, the prevalence of obesity (body mass index [BMI] >95th percentile) among adolescents aged 12–19 years quadrupled from 1966 to 2003–2006 (from 4.6% to 17.6%) [1Ogden C.L. Flegal K.M. Carroll M.D. et al.Prevalence and trends in overweight among US children and adolescents, 1999-2000.J Am Med Assoc. 2002; 288: 1728-1732Crossref PubMed Scopus (3254) Google Scholar, 2Ogden C.L. Carroll M.D. Flegal K.M. High body mass index for age among US children and adolescents, 2003-2006.J Am Med Assoc. 2008; 299: 2401-2405Crossref PubMed Scopus (1454) Google Scholar]. Currently one in three (34.9%) U.S. adolescents are overweight or obese (BMI >85th percentile) [[2]Ogden C.L. Carroll M.D. Flegal K.M. High body mass index for age among US children and adolescents, 2003-2006.J Am Med Assoc. 2008; 299: 2401-2405Crossref PubMed Scopus (1454) Google Scholar]. The prevalence of adolescent obesity is highest among black, Hispanic, and American Indian youth and among youth from lower-income households [3Singh G.K. Kogan M.D. Van Dyck P.C. et al.Racial/ethnic, socioeconomic, and behavioral determinants of childhood and adolescent obesity in the United States: Analyzing independent and joint associations.Ann Epidemiol. 2008; 18: 682-695Abstract Full Text Full Text PDF PubMed Scopus (242) Google Scholar, 4Caprio S. Daniels S.R. Drewnowski A. et al.Influence of race, ethnicity, and culture on childhood obesity: Implications for prevention and treatment.Obesity. 2008; 16: 2566-2577Crossref PubMed Scopus (105) Google Scholar]. Overweight causes adverse health, social, and emotional outcomes and increases adolescents' risk of disability and premature death as adults. Of great concern is the increasing prevalence of type 2 diabetes among adolescents, which is associated with obesity and becomes more common after age 10 years. Two million adolescents (or one in six overweight adolescents) have prediabetes [[5]American Diabetes Association Total prevalence of diabetes and pre-diabetes. Available at.http://diabetes.org/diabetes-statistics/prevalence.jspGoogle Scholar]. Metabolic and physiologic abnormalities associated with obesity in adolescence (e.g., hypertension, dyslipidemias, orthopedic problems, type 2 diabetes) tend to track into adulthood along with the condition of obesity itself. Obesity during adolescence is the single best predictor of adult obesity [[6]Dietz W.H. Gortmaker S.L. Preventing obesity in children and adolescents.Annu Rev Public Health. 2001; 22: 337-353Crossref PubMed Scopus (447) Google Scholar]. Dietz and Gortmaker [[7]Dietz W.H. Critical periods in childhood for the development of obesity.Am J Clin Nutr. 1994; 59: 955-959PubMed Google Scholar] identified three critical periods in childhood for the development of obesity: the prenatal period, the period of adiposity rebound, and adolescence. These critical periods highlight not only the importance of the adolescent stage but also the necessity of applying a life-course approach to the prevention of obesity.Although a wide range of behavioral, genetic, biological, and environmental factors contribute to the development of obesity, energy imbalance resulting from limited physical activity and excess energy intake are considered the most important factors. Wang et al [[8]Wang Y.C. Gortmaker S.L. Sobol A.M. et al.Estimating the energy gap among US children: A counterfactual approach.Pediatrics. 2006; 118: e1721-e1733Crossref PubMed Scopus (205) Google Scholar] found that U.S. children and adolescents experienced an average "energy gap" (i.e., surplus of energy intake over energy expenditure) of 165 calories per day over the period from the 1988 and 1994 NHANES to the 1999–2002 NHANES surveys, leading to an excess 10 pounds of body weight for all adolescents, 1 pound per year, on average. Overweight adolescents consumed an average of 700–1000 more calories per day, which resulted in an average weight gain of 58 extra pounds beyond that associated with normal growth, almost 6 pounds per year.The U.K. Foresight report [[9]Butland B, Jeff S, Kopelman P, et al. Foresight. Tackling obesities: Future choices—project report. United Kingdom Government Office for Science. Available at, http://www.foresight.gov.uk/OurWork/ActiveProjects/Obesity/Obesity.asp. Accessed June 30, 2009.Google Scholar] has framed obesity as an imbalance in energy caused by a complex multifaceted system of determinants in which no single influence dominates. The investigators concluded that at the heart of the issue of excess weight lies a biological system struggling to cope in a fast-changing world in which the pace of technological revolution has outstripped human evolution. Biologically based preferences for energy-dense foods and energy-conserving activities were adaptive in environments with periodic food shortages, but not in today's world. Adolescents today live in a society that has changed drastically in the past few decades during which obesity has increased so dramatically. In the past three to four decades, there have been major societal changes affecting physical activity, such as increased opportunities for sedentary recreation and fewer opportunities for active transport, with physical activity being engineered out of adolescents' daily routines [[10]Sturm R. Childhood obesity—what we can learn from existing data on societal trends, part 2.Prevent Chron Dis. 2005; 2 (Available at) (Accessed June 30, 2009): A20http://www.cdc.gov/pcd/issues/2005/apr/04_0039.htmPubMed Google Scholar]. Only 8% of middle schools and 2% of high schools provide daily physical education or its equivalent [[11]Lee S.M. Burgeson C.R. Fulton J.E. et al.Physical education and physical activity: Results from the School Health Policies and Programs Study 2006.J Sch Health. 2007; 77: 435-463Crossref PubMed Scopus (328) Google Scholar], and there has been a significant decrease in the number of youth who walk or bike to school [[12]McDonald N.C. Active transportation to school: Trends among US school children, 1969–2001.Am J Prev Med. 2007; 32: 509-516Abstract Full Text Full Text PDF PubMed Scopus (496) Google Scholar]. In addition, adolescents are spending more sedentary time using electronic media, such as television, computer games, and the Internet [[13]Rideout V. Roberts D. Foehr U. Generation M. Media in the lives of 8–18 year-olds. Kaiser Family Foundation, Menlo Park, CA2005Google Scholar]. Environments that make it difficult for youth to be active are believed to be partially responsible for the low prevalence of adolescents meeting the recommended 60 minutes per day of moderate-to-vigorous physical activity—less than 10% of adolescents as measured by objective accelerometers in a national sample [[14]Troiano R.P. Berrigan D. Dodd K.W. et al.Physical activity in the United States measured by accelerometer.Med Sci Sports Exerc. 2008; 40: 181-188Crossref PubMed Scopus (5299) Google Scholar].At the same time, cumulative changes in adolescents' food environments have increased the marketing, availability, appeal, affordability, and consumption of foods and beverages that are low in nutrients but high in fat, sugar, and calories. Few adolescents eat the amounts of fruits, vegetables, whole grains, and calcium-rich foods as recommended in the Dietary Guidelines for Americans, and many consume excess calories, sugar, total and saturated fats, and sodium. Middle and high schools frequently sell high-calorie, low-nutrition beverages and foods in vending machines and a la carte in the cafeteria [[15]Fox M.K. Gordon A. Nogales R. et al.Availability and consumption of competitive foods in US public schools.J Am Diet Assoc. 2009; 109: S57-S66Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar]. In addition, an increasing number of adolescents living in underserved communities do not have access to food stores that stock and sell affordable healthy foods. Over the past few decades, the cost of high-calorie, low-nutrition foods has decreased whereas the cost of more healthful foods such as fruits and vegetables has increased [[16]Powell L.M. Chaloupka F.J. Food prices and obesity: Evidence and policy implications for taxes and subsidies.Milbank Q. 2009; 87: 229-257Crossref PubMed Scopus (326) Google Scholar].In short, the consistent rise in the prevalence of obesity among children and adolescents since the 1970s reflects the cumulative effects of these changes in the external environment and underscores the need to identify and modify the environmental influences that could help to alter both energy intake and energy expenditure at the population level. Huang and Glass [[17]Huang T.T. Glass T.A. Transforming research strategies for understanding and preventing obesity.J Am Med Assoc. 2008; 300: 1811-1813Crossref Scopus (107) Google Scholar] point out that shifting the population distribution of obesity will require interventions and strategies that include targeting food environments and physical activity environments, especially among groups most at risk for obesity. McKinnon et al [[18]McKinnon R.A. Orleans C.T. Kumanyika S.K. et al.Considerations for an obesity policy research agenda.Am J Prev Med. 2009; 36: 351-357Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar] similarly emphasize the importance of public policies as a tool to alter the built and food environment to improve population-level diet and physical activity behaviors. There is growing recognition that environmental and policy approaches can affect large populations, can reach traditionally underserved populations, are likely to have long-term or permanent effects, and can augment and support educational and behavior change interventions to make them more effective. According to the Institute of Medicine [[19]Institute of Medicine (US), Committee on Prevention of Obesity in Children and Youth Koplan J. et al.Preventing Childhood Obesity: Health in the Balance. National Academies Press, Washington, DC2005Google Scholar], the U.S. Surgeon General [[20]The Surgeon General's call to action to prevent and decrease overweight and obesity. US Dept. of Health and Human Services, Public Health Service, Washington, DC2001Google Scholar], and the World Health Organization [[21]Global strategy on diet, physical activity, and health. Geneva, Switzerland: World Health Organization, 2004. Available at: http://www.who.int/gb/ebwha/pdf_files/WHA57/A57_R17-en.pdf.Google Scholar], environmental and policy interventions must be at the center of efforts to reverse the rise in childhood obesity. In the long term, these environmental and policy changes may not only reduce health and disability costs but may also produce a healthier and more environmentally sustainable society [[9]Butland B, Jeff S, Kopelman P, et al. Foresight. Tackling obesities: Future choices—project report. United Kingdom Government Office for Science. Available at, http://www.foresight.gov.uk/OurWork/ActiveProjects/Obesity/Obesity.asp. Accessed June 30, 2009.Google Scholar].The 2005 Institute of Medicine report, Preventing Childhood Obesity: Health in the Balance [[19]Institute of Medicine (US), Committee on Prevention of Obesity in Children and Youth Koplan J. et al.Preventing Childhood Obesity: Health in the Balance. National Academies Press, Washington, DC2005Google Scholar] concluded that environmental and policy influences are potentially the most powerful—but currently least well understood—strategies for addressing child and adolescent obesity. At present, relatively little is known about the most effective and feasible policy initiatives to modify children's food and physical activity environments. The need to find the most effective population-level obesity prevention strategies is among the most profound challenges in public health today [[17]Huang T.T. Glass T.A. Transforming research strategies for understanding and preventing obesity.J Am Med Assoc. 2008; 300: 1811-1813Crossref Scopus (107) Google Scholar]. It is widely acknowledged that we need to identify obesity prevention strategies that are feasible and effective and then work with public health practitioners, schools, community coalitions and policymakers at all levels to implement these approaches [[22]Sallis J.F. Story M. Orleans C.T. A research perspective on findings from Bridging the Gap.Am J Prev Med. 2007; 33: S169-S171Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar]. A recent survey of state health department chronic disease directors found that nearly half reported that they did not believe that they had adequate quality research to help them construct effective obesity prevention and reduction strategies in their states [[23]Levi J, Segal LM, Juliano C. Just for America's Health. F as in fat. How obesity policies are failing in America. Available at: http://healthyamericans.org/reports/obesity2006/Obesity2006Report.pdf. Accessed June 22, 2009.Google Scholar]. They emphasized the need for additional research to identify evidence-based interventions and "best practice" guidelines for programs. Given the importance of finding and implementing effective public health strategies for addressing child and adolescent obesity overall and in high-risk populations, systematic "solution-oriented" and fast-track policy and environmental research is needed [22Sallis J.F. Story M. Orleans C.T. A research perspective on findings from Bridging the Gap.Am J Prev Med. 2007; 33: S169-S171Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar, 24Robinson T.N. Sirard J.R. Preventing childhood obesity: A solution-oriented research paradigm.Am J Prev Med. 2005; 28: 194-201Abstract Full Text Full Text PDF PubMed Scopus (133) Google Scholar].To fill critical gaps in research, an increasing number of funders have placed a high priority on funding research to identify key policy and environmental determinants of rising youth obesity trends and to find effective and sustainable policy and environmental solutions to reverse these trends, with a special focus on the populations and communities at highest risk. To increase their impact and speed of discovering and applying evidence-based interventions, the Centers for Disease Control and Prevention, National Institutes of Health, and Robert Wood Johnson Foundation (RWJF) recently joined forces to launch a National Collaborative on Childhood Obesity Research (NCCOR). Through NCCOR (http://www.nccor.org), they will work collectively to improve the efficiency and effectiveness of childhood obesity studies—evaluating new and existing prevention approaches, rapidly assessing promising policy changes, and speeding the application of interventions that work.The articles in this supplement are based on research funded by the RWJF, which has invested significantly in research programs and evaluations addressing both sides of the energy balance equation, with the aim of providing key decision and policy makers with evidence to guide and accelerate effective action to reverse the rise in childhood obesity [22Sallis J.F. Story M. Orleans C.T. A research perspective on findings from Bridging the Gap.Am J Prev Med. 2007; 33: S169-S171Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar, 25Chaloupka F.J. Johnston L.D. Bridging the Gap: Research informing practice and policy for healthy youth behavior.Am J Prev Med. 2007; 33: S147-S161Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar]. RWJF's research initiatives, the largest of which are described below, are designed to inform action and create change and have generated a large number of peer-reviewed publications, as well as numerous policy-relevant research briefs and syntheses, monographs, and journal supplements.•Active Living Research (ALR) and Healthy Eating Research (HER) support investigator-initiated research to identify and evaluate policies and environmental approaches that have the greatest potential to reverse the nation's rising levels of childhood obesity, especially among children ages 3–18 at highest risk for obesity on the basis of income, race/ethnicity or location. Both programs support studies and analyses of school, local, state and federal policies, including "rapid response" studies of naturally occurring policy and environmental changes (so-called "natural experiments") that are taking place in states, communities and schools across the country. The shared core goals of ALR and HER are as follows: 1) to establish a strong research base regarding policy and environmental factors that influence (either healthy eating or physical activity) and body weight in children and adolescents, as well as effective policy and environmental strategies for reversing the childhood obesity epidemic; 2) to build a vibrant, multidisciplinary field of research and a diverse network of researchers; and 3) to ensure that findings are rapidly synthesized and communicated to inform policy debates, public health action, and advocacy and to guide the development of effective solutions. More information on ALR and HER, as well as policy-relevant research briefs and syntheses, monographs and journal supplements, can be found on their respective Web sites (www.activelivingresearch.org and www.healthyeatingresearch.org).•With a primary focus on adolescents, Bridging the Gap has created a national school- and community-based surveillance system to annually assess the impact of school, community, state and national policies, programs, and other environmental influences on diet, physical activity, and self-reported BMI among nationally representative cross-sectional samples of 8th, 10th, and 12th graders [[25]Chaloupka F.J. Johnston L.D. Bridging the Gap: Research informing practice and policy for healthy youth behavior.Am J Prev Med. 2007; 33: S147-S161Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar]. Results are summarized and synthesized in annual monographs that can be found on the relevant Web sites (www.bridgingthegapresearch.org and www.impacteen.org).•A grant to the Yale University Rudd Center for Food Policy and Obesity supports strategic food marketing research, including "quick strike" studies on policies and practices related to food advertising and marketing aimed at children and adolescents (www.yaleruddcenter.org).Growing findings from these initiatives and research funded by other agencies have shown that adolescents are especially vulnerable to unhealthy food and physical activity environments, at a time when lifelong health behaviors are being established. Thus, this supplement to the Journal of Adolescent Health focuses on adolescent obesity and the need for evidence-based policy and environmental solutions. The purpose of the supplement is to highlight recent findings from Healthy Eating Research grantees, Active Living Research grantees, Bridging the Gap, and The Rudd Center that illustrate the breadth and depth of research related to adolescent obesity prevention and its relevance for informing policy changes.The supplement starts with a Commentary by Risa Lavizzo-Mourey, M.D., M.B.A., President and CEO of RWJF, that was adapted from her keynote presentation at the 2008 Society for Adolescent Medicine's annual meeting, "Adolescent Obesity: Prevention and Treatment." [[26]Lavizzo-Mourey R. The adolescent obesity epidemic.J Adolesc Health. 2009; 45: S6-S7Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar]. Her commentary describes the scope of the adolescent obesity epidemic, its impact on health and society, and the foundation's vision for reversing the epidemic by 2015. The paper by Brownell and colleagues [[27]Brownell K.D. Schwartz M.B. Puhl R.M. et al.The need for bold action to prevent adolescent obesity.J Adolesc Health. 2009; 45: S8-S17Abstract Full Text Full Text PDF PubMed Scopus (99) Google Scholar] was based on Brownell's distinguished Gallagher Lectureship at the 2008 annual meeting, which called for "bold action to prevent adolescent obesity." The paper underscores the urgent need for changes in the environment and makes the case that modern conditions have created an environment that makes unhealthy behavior the "default" and adolescent obesity a predictable and inevitable consequence, and presents a framework for action for creating "optimal defaults" to promote healthier eating and physical activity.The studies of healthy eating policies and environments in this issue deal with improving the food environment at schools, food marketing, and soda taxes. Schools can become one of the most effective partners in the fight against obesity by ensuring the environment is conducive to healthy eating and physical activity. The paper by Johnson et al [[28]Johnson D.B. Bruemmer B. Lund A.E. et al.Impact of school district sugar-sweetened beverage policies on student beverage exposure and consumption in middle schools.J Adolesc Health. 2009; 45: S30-S37Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar] found that sugar-sweetened beverage (SSB) exposure in middle schools was a significant predictor of SSB consumption during the school day. Furthermore, SSB policy was a significant predictor of SSB exposure. Terry-McElrath et al [[29]Terry-McElrath Y.M. O'Malley P.M. Delva J. et al.The school food environment and student body mass index and food consumption: 2004 to 2007 national data.J Adolesc Health. 2009; 45: S45-S56Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar] examined trends in the availability of foods in 684 middle and high schools from 2004–2007 and found a decreasing trend in the availability of regular sugar and high-fat food items. Suggestive evidence was observed for a relationship between the school food environment and student BMI. Samuels et al [[30]Samuels S.E. Lawrence Bullock S. Woodward-Lopez G. et al.To what extent have high schools in California been able to implement state-mandated nutrition standards?.J Adolesc Health. 2009; 45: S38-S44Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar] examined factors associated with implementation of California's school nutrition standards 1 year after standards became effective. They found the majority of schools were adhering to the required beverage standards; however, none of the schools selling competitive foods were 100% adherent to the nutrient-based food standards.Food and beverage marketing is a potent factor influencing food choices and weight status of youth [[31]Institute of Medicine (US)Committee on Food Marketing and the Diets of Children and Youth McGinnis J.M. Gootman J.A. et al.Food marketing to children and youth: Threat or opportunity?. National Academies Press, Washington, DC2006Google Scholar]. Brownell et al [[27]Brownell K.D. Schwartz M.B. Puhl R.M. et al.The need for bold action to prevent adolescent obesity.J Adolesc Health. 2009; 45: S8-S17Abstract Full Text Full Text PDF PubMed Scopus (99) Google Scholar] describe adolescents' increased vulnerability to food marketing messages because of developmental concerns related to appearance, self-identity, belonging, and their reduced ability to inhibit impulsive behaviors and delayed gratification. On a related topic, Montgomery and Chester [[32]Montgomery K.C. Chester J. Interactive food and beverage marketing: Targeting adolescents in the digital age.J Adolesc Health. 2009; 45: S18-S29Abstract Full Text Full Text PDF PubMed Scopus (158) Google Scholar] provide one of the first reviews of interactive food and beverage marketing and the new media and marketing ecosystem targeting adolescents, and they recommend policy and regulatory initiatives to reduce the negative impact of the digital marketplace.One public health measure currently being debated to help prevent obesity and as a potential measure to generate revenue for health reform efforts is taxing soft drinks [[33]Brownell K.D. Frieden T.R. Ounces of prevention—the public policy case for taxes on sugared beverages.N Engl J Med. 2009; 360: 1805-1808Crossref PubMed Scopus (350) Google Scholar]. Using national data from Bridging the Gap, Powell et al [[34]Powell L.M. Chriqui J. Chaloupka F.J. Associations between state-level soda taxes and adolescent body mass index.J Adolesc Health. 2009; 45: S57-S63Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar] examined the association between state-level grocery store and vending machine soda tax rates and adolescents' BMI.Active living–related papers focus on schools and parks, both of which are common settings for adolescent physical activity that can be influenced by policy. Using national data from Bridging the Gap, O'Malley et al [[35]O'Malley P.M. Johnston L.D. Delva J. et al.School physical activity environment related to student obesity and activity: A national study of schools and students.J Adolesc Health. 2009; 45: S71-S81Abstract Full Text Full Text PDF PubMed Scopus (33) Google Scholar] found that school physical education policies, and practices were not related to adolescents' BMI, and the authors advised that increased quantity and intensity of physical education is needed to make a difference in BMI. However, more participation in intramural sports was related to lower BMIs. Barroso et al [[36]Barroso C.S. Kelder S.H. Springer A.E. et al.Senate Bill 42: Implementation and impact on physical activity in middle schools.J Adolesc Health. 2009; 45: S82-S90Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar] evaluated a Texas state law mandating 30 minutes of daily physical activity in middle schools and found generally good adherence, even in the lowest-income areas in the state. In their study of mainly African-American adolescents, Ries et al [[37]Ries A.V. Voorhees C.C. Roche K.M. et al.A quantitative examination of park characteristics related to park use and physical activity among urban youth.J Adolesc Health. 2009; 45: S64-S70Abstract Full Text Full Text PDF PubMed Scopus (120) Google Scholar] reported that park use was related to greater perceptions of park proximity, park quality, and use by friends. Cradock et al [[38]Cradock A.L. Melly S.J. Allen J.G. et al.Youth destinations associated with objective measures of physical activity in adolescents.J Adolesc Health. 2009; 45: S91-S98Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar] found that adolescents were more physically active after school when school neighborhoods had less traffic and more destinations within walking distance. This study extends previous findings that policies related to community design and transportation are relevant for youth physical activity.The articles in this supplement of the Journal of Adolescent Health demonstrate the value of research in documenting favorable trends such as healthier foods in schools [29Terry-McElrath Y.M. O'Malley P.M. Delva J. et al.The school food environment and student body mass index and food consumption: 2004 to 2007 national data.J Adolesc Health. 2009; 45: S45-S56Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar, 30Samuels S.E. Lawrence Bullock S. Woodward-Lopez G. et al.To what extent have high schools in California been able to implement state-mandated nutrition standards?.J Adolesc Health. 2009; 45: S38-S44Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar] and effective school policies providing healthier food [[30]Samuels S.E. Lawrence Bullock S. Woodward-Lopez G. et al.To what extent have high schools in California been able to implement state-mandated nutrition standards?.J Adolesc Health. 2009; 45: S38-S44Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar] and more physical activity [[36]Barroso C.S. Kelder S.H. Springer A.E. et al.Senate Bill 42: Implementation and impact on physical activity in middle schools.J Adolesc Health. 2009; 45: S82-S90Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar] that can be adopted by other states. The data reported here can provide guidance about how to increase use of parks by African-American adolescents [[37]Ries A.V. Voorhees C.C. Roche K.M. et al.A quantitative examination of park characteristics related to park use and physical activity among urban youth.J Adolesc Health. 2009; 45: S64-S70Abstract Full Text Full Text PDF PubMed Scopus (120) Google Scholar], policy changes in schools that can reduce adolescents' sugar-sweetened beverage intake [[28]Johnson D.B. Bruemmer B. Lund A.E. et al.Impact of school district sugar-sweetened beverage policies on student beverage exposure and consumption in middle schools.J Adolesc Health. 2009; 45: S30-S37Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar], and the potential for increased soda taxes to reduce consumption [[34]Powell L.M. Chriqui J. Chaloupka F.J. Associations between state-level soda taxes and adolescent body mass index.J Adolesc Health. 2009; 45: S57-S63Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar]. Other papers demonstrate the many areas in need of further research and intervention. More improvements are recommended so that physical education will contribute more to obesity prevention [[35]O'Malley P.M. Johnston L.D. Delva J. et al.School physical activity environment related to student obesity and activity: A national study of schools and students.J Adolesc Health. 2009; 45: S71-S81Abstract Full Text Full Text PDF PubMed Scopus (33) Google Scholar]. Adolescents appear to be particularly susceptible to food marketing [[27]Brownell K.D. Schwartz M.B. Puhl R.M. et al.The need for bold action to prevent adolescent obesity.J Adolesc Health. 2009; 45: S8-S17Abstract Full Text Full Text PDF PubMed Scopus (99) Google Scholar], and marketers are using new digital-age tools to target youth [[32]Montgomery K.C. Chester J. Interactive food and beverage mar
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