Childhood Obesity Session II

1
Childhood ObesitySession II

• Roland Sturm, Ph.D.
• Senior Economist
• RAND

2
Why the Recent Obesity Epidemic?

• Many competing hypotheses
• Television/Video
• Too much homework
• Less exercise
• More fast food
• Urban Sprawl/Car Culture
• Identifying major social trends can suggest
  promising interventions
• Actual changes at times surprising

3
What has changed in childrens lives?

• We will look at trends in
• Time Use
• Media Consumption
• Studying at Home
• Transportation Patterns
• Physical Education
• Nutrition

4
This session is not about health care!

• Obesity has major effects on health care use
  among adults
• But the most effective solutions are in
  prevention, not treatment (at this point)
• Health plans and health care settings have little
  leverage
• Environmental influences on health

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1. Time Use

• Best methodology time diaries
• Census Bureau started collecting time diary data
  in 2003
• For adults, 1965-1985 data from Robinson and
  Godbey my calculations from 1999 survey
• For children, only two surveys available 1981
  and 1997 (Hofferth and Sandberg)
• Time allocation important for physical activity,
  less for nutrition

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While Adults Have More Free Time .
Source Robinson and Godbey, 1999 my calculation
using FISCT 1999
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. Free Time for Children Declined from 1981 to
1997 (in mins/week)
Source calculations based on data from Hofferth
and Sandberg (2001)
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Trends in Time Use

• For adults 18-64, free time increased by 6 hours
  per week from 1965 to 1995
• increase for both men and women
• in or out of labor force
• For children 3-12, free time decreased by 7 hours
  per week from 1981 to 1997

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Changes in Weekly Minutes Spent on Activities
from 1981 to 1997, Age 3-12
Figure 2 Changes in Weekly Minutes Spent on
Activities from 1981 to 1997, Age 3-12
Source calculation based on data from Hofferth
and Sandberg (2001b)
Source calculations based on data from Hofferth
and Sandberg (2001)
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Changes in Weekly Minutes Spent on Activities
from 1981 to 1997, Age 3-5
Source calculation based on data from Hofferth
and Sandberg (2001b)
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Changes in Weekly Minutes Spent on Activities
from 1981 to 1997, Age 6-8
Source calculation based on data from Hofferth
and Sandberg (2001b)
12
Changes in Weekly Minutes Spent on Activities
from 1981 to 1997, Age 9-12
Source calculation based on data from Hofferth
and Sandberg (2001b)
13
What has changed in childrens lives?

• We will look at trends in
• Time Use
• Media Consumption
• Studying at Home
• Transportation Patterns
• Physical Education
• Nutrition

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2. Media Consumption

• Common hypotheses
• Children watch more TV
• Children spend too much time playing video games,
  on computer
• No trend data available except TV
• But KFF point-in-time media use project

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Continuing Decline in TV Watching Among
Teenagers 1991-2001
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Media Use Among 8-18 Year Olds (hours per day)

• Medium White Black Hispanic
• Total 716 952 902
• Television 247 441 350
• TapedTV 012 027 018
• Videotapes 028 032 034
• Movies 013 029 035
• Videogames 023 035 035
• PrintMedia 043 116 035
• Radio 049 045 056
• CDsandTapes 109 103 108
• Computer 031 031 029

Source Kaiser Family Foundation, 1999, kds
media _at_ the new millennium.
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Summary Media Consumption

• Noticeable decline in television watching
• Computer/video games relatively small share of
  media budget
• Total comparable to TV decline
• Either little change in screen time or decline

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What has changed in childrens lives?

• We will look at trends in
• Time Use
• Media Consumption
• Studying at Home
• Transportation Patterns
• Physical Education
• Nutrition

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3. Studying at Home

• Claims that homework overburdens children and
  limits learning with lack of physical activity
  and weight gain being major secondary
  consequences (Kralovec Buell, 2000).
• There is indeed a large increase in childrens
  occupational time
• includes studying at home, day care and after
  school programs
• Could changes in homework account for this?

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Proportion of adolescents doing 1 hour or more of
homework, 1978-1999
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Homework trends for 9-year-olds, 1984-1999
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Summary Studying at Home

• Studying at home not cause for childrens
  increased occupational time
• Increased homework loads cannot play any role in
  weight gain/declining physical activity
• Refutes prominent hypotheses in education
  literature
• Main reason for increased occupational time
  after-school and daycare

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What has changed in childrens lives?

• We will look at trends in
• Time Use
• Media Consumption
• Studying at Home
• Transportation Patterns
• Physical Education
• Nutrition

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Walking to School as Percent of School Trips
(Children 5-15)
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Total Number of Daily Trips
Source NPTS 1977, 1990 and NHTS 2001 for
children 5-15
26
Average Active Travel Time in Minutes (Children
5-15)
Source NPTS 1977, 1990 and NHTS 2001 for
children 5-15
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Summary Transportation

• Decline in walking to school opportunity for
  interventions to increase physical activity
• Not clear that changes in transportation reduced
  physical activity
• Possibly even small increase in active travel
  because of increased number of trips
• But total amount of active travel remains
  negligible not even 10 minutes/day

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What has changed in childrens lives?

• We will look at trends in
• Time Use
• Media Consumption
• Studying at Home
• Transportation Patterns
• Physical Education
• Nutrition

29
Physical Activity at School

• School and afterschool/daycare important as
  children spent more time in those settings
• Widespread belief that PE is declining
• Only trend data for high school

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Percentage of students who attended PE class one
or more days during an average school week
Source CDC, YRBS, various years
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Percent of students who exercised or participated
in physical activities for at least 20 minutes
that made them sweat and breathe hard on three or
more of the past seven days
Source CDC, YRBS, various years
32
Percent of students attending daily PE classes
Source CDC, YRBS, various years
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Physical Activity At School

• For adolescents, not clear that PE declined
• Overall PA for adolescents seems constant
• No trend data on younger children, although time
  in organized sports increased
• Missing What is going on in afterschool/daycare?
• Important policy lever as PE as early as
  elementary school can substantially reduce
  further weight gain among heaviest girls

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What has changed in childrens lives?

• We will look at trends in
• Time Use
• Media Consumption
• Studying at Home
• Transportation Patterns
• Physical Education
• Nutrition

35
While Leisure Industries Are Growing Fast, Food
Industries Decline in Importance
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But Supply More Calories
37
US Food Supply for Macronutrients
Source USDA, Economic Research Service    
38
Daily Fat and Carbohydrate Intake for Boys and
Girls Ages 6-11
Source Enns et al. (2002) based on Continuing
Survey of Food Intakes by Individuals (CSFII)
1994-96, 1998 CSFII 1989-91 Nationwide Food
Consumption Survey 1977-78.
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Price Indices
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Total Caloric Sweeteners
Source USDA Economic Research Service
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Interventions? Politically touchy

• See fight about 2003 WHO report, which says
• Overall, the evidence implicating a high intake
  of sugars-sweetened drinks in promoting weight
  gain was considered moderately strong.
• Part of the consistent, strong relationships
  between television viewing and obesity in
  children may relate to the food advertising to
  which they are exposed.
• Fastfood restaurants, and foods and beverages
  that are usually classified under the eat
  least category in dietary guidelines are among
  the most heavily marketed products, especially on
  television.

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Hardball Responses From Industry

• For example, an excerpt from a letter from the
  Sugar Association
• The senators referred to are John Breaux and
  Larry Craig

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Summary Nutrition

• Time spent eating as a primary activity has
  declined, suggesting a shift towards snacking or
  eating as a secondary activity.
• Statistically significant increase in
  carbohydrate intake
• Price and income data suggest possible economic
  reasons
• Price index for fresh fruit and vegetables far
  exceeded general inflation, whereas real price
  for sugars, sweets, soft drinks fell.

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Conclusion

• Biggest changes are decline in childrens free
  time and nutrition
• No major trends in PA related to PE, active
  travel (except walk to school), home studying,
  media
• Increased time in school, daycare, and
  after-school programs offer opportunities for
  intervention
• Both for PA and nutrition