Nutrition & Physical Activity Intervention Effectiveness Systematic Reviews & Evidence-Based Recommendations - PowerPoint PPT Presentation

Systematic Reviews & Evidence-Based Recommendations

Laurie M. Anderson, PhD, MPH

Centers for Disease Control & Prevention

Explosive growth of scientific information

• too much to keep up with
• contradictory results

The body of intervention literature can be quite large, inconsistent, and uneven in quality

• Combine many studies with different methods and results
• Look for consistencies in set of findings
• More robust than single study
• May pinpoint why studies differ
• Shows what is effective and why

• Independent Task Force
• Goal - to provide a comprehensive set of evidence-based recommendations on the effectiveness and feasibility of health promotion & disease prevention interventions in community settings

Jonathan Fielding, Chair Public Health Los Angeles Co, UCLA

Barbara Rimer, Vice Chair University North Carolina Chapel Hill

Noreen Clark University Michigan School of Public Health

John Clymer Partnership for Prevention

Kay Dickersin US Cochrane Center, Brown University

Alan Hinman Task Force on Child Survival

Robert Johnson New Jersey Medical School

Garland Land Missouri Department of Health

Patricia Noland Rhode Island Department of Health

Alonzo Plough Seattle King County Department of Health

Nico Pronk HealthPartners

Dennis Richling Midwest Business Group on Health

Steven Teutsch Merck & Company

• Multidisciplinary team of experts
• Develop conceptual framework
• Prioritize intervention topics
• State precise purpose of the review
• Search for and retrieve evidence
• Rate quality of evidence
• Summarize evidence
• Translate into a recommendation

• Program effectiveness
• Feasibility of implementation
• Acceptability to the population
• Unanticipated harms (or benefits)
• Cost-effectiveness

Logic Framework: Nutrition and Community Health

IntermediateOutcomes

Modifiable Determinants

POPULATION FOOD INTAKE

Food Consumption Patterns (e.g. fruits, vegetables)

Intake of Nutrients and Food Components:

Vitamins

Minerals

Fiber

Fats

Other food constituents

Dietary supplements

Alcohol

Energy balance

• Food Supply Factors
• Agriculture policy
• Nutrition policy
• Science and technology
• Food production, processing, storage and distribution
• Food fortification
• Food safety

Physiologic Indicators:

Growth

Adipose tissue

Musculoskeletal

Gastrointestinal

Metabolic

Cardiovascular

Reproductive

Immunological

Neurological

I

N

T

E

R

V

E

N

T

I

O

N

S

• Environmental Factors
• Food Availability & Price
• Neighborhoods
• Schools
• Worksites
• Homes
• Local, state & national food assistance programs

Community

Health

Outcomes

Life Stage

Requirements

Pregnancy

Lactation

Childhood

Adolescence

Adulthood

Older Adulthood

• Morbidity
• Mortality
• Measures of Health & Fitness
• Quality of Life

• Consumer Demand
• Household resources
• Nutrition knowledge
• Cultural practices
• Psychosocial characteristics
• Taste and preferences
• Advertising and marketing

Physical

Activity

Patterns

Genetics,

Co-morbidities

Priority Ranked Topics for Nutrition

• Food & beverage availability in schools.
• Comprehensive community approaches to increase fruit & vegetable intake.
• Food and beverage advertising to children.
• Food & beverage availability, price, portion size, and labeling in restaurants.

Food choice and nutrition education in food assistance programs.

• Nutrition and weight management counseling in healthcare settings.
• Breast-feeding.
• Product labeling in grocery stores, restaurants and vending machines.
• Food & beverage availability and price in worksites.
• Use of dietary supplements across the lifespan.

Nutrition Topic Review

Question:

Do multi-component, school-based interventions improve nutrition-related behaviors and nutritional status of children and adolescents.

Definition:

School-based nutrition interventionsimplemented in K-12th grades to promote healthy nutritional attitudes, knowledge and behavior, including eating and physical activity.

The interventions are multi-component and may target food policy, environmental factors and/or nutrition education. Interventions may be directed at school administrators, food service staff, teachers or parents or delivered by special program instructors directly to students.

Study Outcomes

School policy

Behaviors

Dietary intake

Physical activity

Environmental

support for healthy choices

Knowledge Nutritional needsFood content

Attitudes Self-care Body image

Abilities Self-assessment Behavioral

change skills Media literacy

Physiologic

Indicators Normal growth & development Fitness

Health status

School

achievement

Multi-component

School-based

Nutrition

Interventions

Nutrition & health

messages

Promotion of

self-awareness,

self-efficacy

• 1980–2003, publications, dissertations, government reports, US & non-US
• 1500 abstracts, ~150 papers, 76 studies
• Dual abstraction completed on 76 studies
• 13 studies did not meet inclusion criteria
• 14 studies excluded due to limitations in quality
• 6 studies excluded due to least suitable design
• 45 reports of 41 studies

Purpose of school intervention program N=41

30

25

20

15

10

5

0

Healthy Diet

Cancer

Obesity

CVD

Intervention Combinations

4 studies reported policy change

Intervention DurationnPercent

< 3 months 14 27%

4 to 9 months 10 22%

10 to 24 months 10 22%

25 to 36 months 9 21%

60 months 2 4%

Not reported 2 4%

Total 45

n Percent

Immediate 24 55%

1 month 7 16%

2-3 months 3 7%

6-12 months 6 13%

24 months 3 7%

48 months 1 2%

Not reported 1 2%

Total 45

Behavioral Outcomes

• Intake of fruit and vegetables
• Intake of fat
• Intake of saturated fat

-1.5 1.0 .5 0 .5 1.0 1.5

Favors Control Favors Treatment

-4 -3 -2 -1 0 1 2 3 4

Favors Treatment Favors Control

-3 -2 -1 0 1 2 3

Favors Treatment Favors Control

-1.5 -1.0 -.5 0 .5 1.0 1.5

Favors Treatment Favors Control

Is there an effect?

Is the effect real?

• Findings are based on self-report of dietary intake
• Reporting bias may account for some of the effect, possibly rendering small effects negligible

• BMI (n=11)

Boys -2.7% Girls -0.3% Overall 0%

• Skinfold thickness (n=8)

Boys 4.3% Girls -5.4% Overall 0%

• Systolic B/P (n=10) Overall 0.3%
• Serum cholesterol (n=11) Overall -3%

Median Effect Size % Δ I - % Δ C

• Number of studies: Sufficient
• Magnitude of reported effect was small
• Fruit & vegetable servings per day: +0.24
• Saturated fat as % kcal: –0.71 % point
• Consistent? Yes
• Biased? Likely

• The Task Force found insufficient evidence to determine whether multicomponent school-based nutrition interventions are effective in increasing fruit and vegetable intake and decreasing fat and saturated fat intake among school-age children.
• Evidence was limited because bias due to self-report of dietary intake could not be ruled out.

Community-wide campaigns

• Large-scale, high intensity, high visibility
• Use of TV, radio, newspaper, information sites
• Multi-component, multi-site
• ‘Combined Package’
• Recommended

Single Component Mass Media

• Knowledge, attitudes, and beliefs, behavior
• Paid advertisements and donated promotion
• TV, radio, newspapers, billboards

Insufficient evidence of effectiveness.

“Point-of-decision” prompts

• Motivational signs placed by elevators and escalators
• Encourage stair use for health/weight control
• Single component

Recommended

• Modified physical education
• Health education
• TV/video game turn off
• College health education

Modified Physical Education

• Modified curricula and policies
• Studies designed to modify the amount of physical activity during PE
• Lifetime activities and games

Recommended

• Health education
• TV/video game turn off
• College health education

• Individually-adapted health behavior change
• Family-based social support
• Other social support

Individually Adapted Health Behavior Change

• Goal setting and self-monitoring
• Building social support
• Behavioral reinforcement
• Structured problem solving
• Relapse prevention

Recommended

Social Support in Community Contexts

• Creating, strengthening, and maintaining social networks
• Use of ‘buddy’ systems
• Contracting
• Walking groups

Recommended

• Family-based social support

• Create or enhance access
• Urban planning – zoning, land use
• Transportation and infrastructure

Creation or Enhanced Access to Places for Physical Activity

• Built environment - trails and/or facilities access
• Reducing barriers - safety, affordability
• Site-specific programs

Recommended

Street-scale Urban Design and Land Use that Supports Physical Activity in Small Geographic Areas - generally limited to a few blocks

• Improved lighting
• Ease and safety of street crossing
• Sidewalk continuity
• Presence of traffic calming structures
• Making aesthetic enhancements

Recommended

Transportation policies and practices that encourage and facilitate walking and bicycling for transportation

• Policy measures such as roadway design standards
• Expanding public transportation services
• Subsidizing public transportation
• Providing bicycle lanes and racks
• Increasing the cost of parking

Insufficient evidence

Recommend

Against

(Strong or

Sufficient

Evidence)

Insufficient

Evidence

Recommend

For

(Strong or

Sufficient

Evidence)

• Lack of evidence does not mean that interventions don’t work
• Interventions for which evidence is insufficient should be more thoroughly researched
• Interventions that either produce no effect or produce harm(s) should not be used

• Much more information about determinants than solutions
• Common outcomes measures
• Measurement Error – intake & physical activity
• Limited duration of intervention studies
• Longer term follow-up measurement

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