Can Eating Disorders and Overweight Prevention Initiatives Be Integrated? Notes From the Field S. Bryn Austin, ScD Division of Adolescent Medicine Children’s Hospital Boston Harvard Medical School
Overview of Presentation • Background • Prevalence and sequelae of eating disorders and obesity • Prevention intervention research for eating disorders and obesity • Planet Health Study • Implications for prevention research, policy
Health Consequences of Eating Disorders • Electrolyte abnormalities • Amenorrhea, impaired growth • Osteoporosis • Cardiac impairment • Dental erosion • Impaired psychosocial and cognitive functioning
Health Consequences of Obesity • Linked with multiple health problems • Diabetes, hypertension, cardiovascular disease, osteoarthritis, cancer • Linked with eating disordered behaviors • Vomiting and laxative use • Bulimia nervosa • Binge eating disorder
Eating Disorders Preventive Interventions • Over 40 preventive intervention studies • Majority found improvement in knowledge and/or attitudes • A few studies found positive behavior change
Eating Disorders Preventive Interventions • Five randomized controlled trials (RCT) with early adolescents • RCT: strongest design for intervention study • 6th-8th grade girls, some include boys • Study sizes ranged from 86 to 1000 youth • Number of sessions ranged from 5 to 18
Eating Disorders Preventive Interventions • Follow-up assessment ranged from three months to two years • Mixed results on intervention impact • Three found improvement in weight concerns • Two found no intervention effect • None found intervention worsened symptoms
Overweight Preventive Intervention • Robinson et al. (2003) • Goals: increase physical activity, reduce TV • Designed for overweight prevention • Not eating disorders prevention • 61 African-American girls, ages 8 to 10 • 12-week pilot intervention involving dance classes, educational discussion sessions
Overweight Preventive Intervention • Results of Robinson et al. intervention: • Reduced TV viewing • Fewer family dinners in front of TV • Improvement in symptoms of unhealthful weight concerns
Study Question Can an overweight prevention program reduce the risk of disordered weight control behaviors in adolescent girls?
Planet Health Study • Obesity prevention RCT • 10 middle schools matched, randomized to intervention or control condition • Two school years: fall 1995 - spring 1997 • Data on nutrition, physical activity, TV time, height, weight, purging, diet pills • Harvard School of Public Health • Drs. Gortmaker, Wiecha, Peterson, Laird • Drs. Field, Austin
Planet Health Study • Eat 5 servings fruit, vegetables per day • Eat fat in moderation • Be active daily or nearly every day • 2 hrs/day TV/screen time Goals: Classroom lessons Physical education lessons 8 social studies 8 math 30 microunits 6 fit checks 8 social science 8 language arts Grades 6 & 7 7 & 8
Overview of Planet Health Results • For girls, intervention vs. control: • Reduced obesity prevalence (OR = 0.47) • Increased obesity remission (OR = 2.2) • Reduced TV time • TV reduction associated with reduced obesity • Increased fruit, vegetable intake • Did not increase disordered weight control • For boys: reduced TV viewing time Gortmaker et al., Arch Ped Adol Med 1999
Measure of Disordered Weight Control Behaviors • Purging: During the past 30 days, did you vomit or take laxatives to lose weight or to keep from gaining weight? • Diet Pills: During the past 30 days, did you take diet pills to lose weight or to keep from gaining weight?
Statistical Analyses • Multivariable regression analyses • Goal: Determine if Planet Health reduced girls risk of adopting disordered weight control behavior after two years • Excluded girls who were already purging, using diet pills at beginning of study (n=21)
Sample Characteristics at Baseline (n=480) * Significant difference between control and intervention groups
% Adopting Disordered Weight Control Behaviors at Follow-up* 6.2% P<0.01 2.8% % *Girls reporting disordered weight control behaviors at baseline excluded. Austin, Field, Wiecha, Peterson, Gortmaker. Arch Ped Adol Med, 2005.
Findings From Planet Health Study Girls in intervention group were less than half as likely as girls in control group to adopt disordered weight control behaviors Odds Ratio 95% CI Control reference Intervention 0.41 (0.22, 0.75) *Model controls for ethnicity Austin, Field, Wiecha, Peterson, Gortmaker. Arch Ped Adol Med, 2005.
Preventive Proportion • Statistic used to estimate public health importance of preventive effect due to beneficial exposure • Interpreted as proportion of new cases of health problem that could be avoided if people received beneficial factor
Est. % of New Disordered Weight Control Cases That May Be Prevented by Planet Health New cases in control schools = 14/226 New cases intervention schools = 7/254 Preventive proportion = 0.59 Interpretation: An estimated 59% of new cases of disordered weight control behavior among girls in control schools might have been prevented if they had received the Planet Health program
Caveats • Small sample size, small number of cases means findings are estimates • Further research essential • Not able to test some possible factors that may be important • Depression, self-esteem
What Have We Learned? • Planet Health model may provide a new direction for eating disorders and obesity prevention • May be first to protect against both disordered weight control and obesity • Sizable estimated preventive impact • More than half of new cases might have been prevented by intervention
What Have We Learned? • Findings consistent with reduced weight concerns in study by Robinson et al. • Clinicians concerned that obesity prevention efforts may worsen eating disorders • No evidence that Planet Health increased eating disorder symptoms • But potential negative effects of other obesity prevention efforts not yet evaluated
Planet Health Strengths • Long-term, intensive integration of program throughout school curriculum • Focus on healthful behavior • Nutrition, physical activity, reduced TV • No explicit focus on eating disorders, obesity • All 6th, 7th grade students participate • Did not single out girls or overweight youth
Implications for Policy and Prevention • Proliferation of initiatives for obesity prevention and surveillance in schools • Health promotion programs like Planet Health • “BMI report cards” and many other initiatives not yet evaluated • Untested initiatives raise concerns • Risk of worsening disordered eating, stigma, burdening schools
Implications for Policy and Prevention • Safety must be established via evaluation • Obesity prevention efforts must test effect on disordered eating, stigma • Feasibility, sustainability of interventions in schools requires minimizing burden • Cost-effectiveness, time efficiency • Linking prevention research may be key to ensuring safety, feasibility, sustainability
Implications for Policy and Prevention • Strategic Plan for NIH Obesity Research • Essential to expand support for collaboration across both prevention fields • New research initiatives needed to: • Establish evaluation guidelines re: disordered eating/stigma for obesity prevention programs • Identify protective aspects of Planet Health • Test novel strategies for integrating obesity/eating disorders prevention research
Acknowledgments We would like to thank our collaborators and students and staff at participating schools. This research was supported by the National Institutes of Child Health and Human Development (HD-30780), Maternal and Child Health Bureau, HRSA (5 T71 MC 00009-12-0), and Centers for Disease Control and Prevention (U48/CCU115807).
Contact Information for Planet Health • Harvard Prevention Research Center • Harvard School of Public Health • 677 Huntington Ave. • Boston, MA 02115 • (617)432-3840 • www.hsph.harvard.edu/prc