Helen Lee Senior Research Associate MDRC h elenleemdrcorg Scientists Sound the Alarm on Obesity Early 2 It is clear that weight control is a major public health problem Experts at the American Public Health Association Annual Meetings declare obesity as problem 1 ID: 529252
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Slide1
Neighborhood Food Availability, Disparities, and Childhood Obesity Risk
Helen Lee
Senior Research
Associate
,
MDRC
h
elen.lee@mdrc.orgSlide2
Scientists Sound the Alarm on Obesity Early
2
“It is clear that weight control is a major public health problem
”
Experts at the American Public Health Association Annual Meetings declare obesity as problem #1
The year is 1952:
1 McDonald’s
in the
nation
6 pack of Coca Cola contains fewer ounces than
one
Big Gulp
10% of the nation is estimated to be obeseSlide3
Despite Warnings, Obesity Rates Rise Dramatically
3
SOURCE: National Health and Nutrition Examination Surveys (NHANES)
Childhood Obesity Prevalence RatesSlide4
And Disparities are Large
4
Percent obese by race/ethnicity
Percent obese by maternal education
SOURCE: Early Childhood Longitudinal Study – Kindergarten Cohort (ECLS-K), 1999 and 2004Slide5
Concerns Are Multi-faceted, but Framing Becomes Simplified
5
Most
research suggests increased calorie consumption
explains
rise in obesity
(Cutler et al. 2003;
Lakdawalla
et al. 2005)Parallels to tobacco control drawn (e.g
, “toxic” exposure
)
Focus efforts upstream: Obesity risk is involuntary and universal
(Lawrence, 2004)
“
Obesogenic
” environments arguably potential culpritsAdvertising and media exposureSupersizing of the food industry
Agri-business (e.g., high fructose corn syrup)
Pricing policySlide6
Policymakers Respond
6
Increasing discussion in policy circles of “food deserts” and their consequences for
disparities
Poor, minority neighborhoods more likely to lack access to healthy food
(Gallagher
2006; Moore &
Diez
-Roux 2006; Powell et al. 2007)First Lady’s “Let’s Move” campaign
Federal Healthy Food Financing Initiative
Policy e
fforts
to decrease exposure to
“
toxic” vendorsL.A.’s fast food establishment moratorium in South Central
NYC’s super-size soda banSlide7
7Slide8
But Empirical Foundation and Evidence is Inconclusive…
8
Research Questions:
Are
there
distinct patterns in food access by neighborhood poverty and race?
Do differences in residential food
availability explain
obesity risk over young childhood?
Do they explain disparities?Slide9
Merged Individual Data on Children with Neighborhood Food Establishments
9
Longitudinal database of children (Early Childhood Longitudinal Study – Kindergarten Cohort (ECLS-K))
Nationally-representative study of 20,000 kindergarteners attending school in 1998-1999
Looked at kids followed from K to 5
th
grade
(7,730 out
of ~11,000 children in full K-5 sample)Longitudinal
national database
of all business
establishments (
National Establishment Time Series Data (NETS))
Use industry
codes, trade name, HQ, sales, and size to isolate food vendorsSlide10
Key Measures
10
Child outcome: changes
in
BMI
percentile
BMI is weight in kg/ height in meters squared
Used BMI-sex-age specific growth charts to calculate where child falls in percentile distribution
Food availability: density per sq. mile
Supermarkets/large-scale
grocery stores
At least $2 million in
sales;
Appended
warehouse clubs, supercentersCorner grocery stores
Grocery stores operated by 3 employees or lessConvenience stores Sell limited line of
goods; Also
includes gas stations
Full-service restaurants
Provide food to patrons who are served and pay after eating
Fast-food restaurants
Limited service, chain
restaurants (based on top 100 list)Slide11
11
Minority
Neighborhoods Have Higher Concentrations
of
Various Food Vendors
SOURCE: NETS 2006 and Census 2000
NOTES: Based on all U.S. non-rural Census tracts, weighted by population. Similar patterns are found when tracts restricted to ECLS-K children in K-5 analytic sample. * denotes difference is significant in reference to majority white neighborhoods (p<0.05).
*
*
*
*Slide12
12
Poorer
Areas
D
o Not Have Worse Access
to
Healthy Food Stores
SOURCE: NETS 2006 and Census 2000
NOTES: Based on all U.S. non-rural Census tracts, weighted by population. Similar patterns are found when tracts restricted to ECLS-K children in K-5 analytic sample. * denotes difference is significant in reference to majority white neighborhoods (p<0.05).Slide13
How One Measures
F
ood
Environments M
ight
M
atter
13
Food
availability measure
Non-poor
Poor
Very
poor
White
Black
Hispanic
Density per 1,000 pop
Supermarkets
0.09
0.07
0.05
0.09
0.05
0.06
Corner stores
0.23
0.52
0.64
0.22
0.48
0.53
Convenience
stores
0.38
0.49
0.47
0.39
0.42
0.41
Fast food
0.32
0.29
0.27
0.34
0.22
0.23
Minimum
distance (miles)
Supermarkets
1.30
1.01
0.94
1.33
0.96
1.05
Corner stores
1.05
0.55
0.46
1.09
0.46
0.57
Convenience
stores
0.77
0.45
0.43
0.79
0.45
0.53
Fast food
1.02
0.72
0.69
1.03
0.68
0.83
Shares (% out
of
all food stores)
Supermarkets
3%
2%
1%
3%
2%
2%
Corner stores
8%
17%
21%
8%
21%
18%
Convenience
stores
14%
17%
15%
14%
18%
15%
Fast food
10%
8%
6%
10%
8%
7%Slide14
Null Findings for Food Availability and Child Weight Outcomes
14
Food
availability (density per square mile)
Coef
P<value
Associations with BMI percentile
at baseline
Supermarkets
0.37
0.38
Corner stores
0.07
0.46
Convenience stores
0.08
0.61
All
other restaurants
0.01
0.73
Fast
food outlets
0.16
0.44
Associations between
c
hange in food outlet
exposure and change in BMI percentile
Supermarkets
0.54
0.58
Corner stores
-0.48
0.68
Convenience stores
0.93
0.37
All
other restaurants
-
0.19
0.73
Fast
food outlets
-
0.66
0.63
SOURCE: ECLS-K, Kindergarten to 5
th
grade panel,
1999-2004, and NETS, 1998-2004
NOTES: First panel estimates show associations between food outlet density (stores per
sq
mile) and child BMI percentile at kindergarten wave, from
cross-classified random-effects models
adjusted for other covariates. Second panel
e
stimates show associations between change in prevalence of food outlets (growth or decline) and change in BMI percentile over elementary school, from cross-classified random-effects models
adjusted for other
covariates, and time. Slide15
Implications
15
How problematic are food deserts?
SSM study: Easy access to food retailers of all types, rather than lack of access, better portrays the food environments of disadvantaged communities
We need to do better job at thinking through the behavioral mechanisms of our policy solutions
Food access likely less important than other factors
“
A millionaire may enjoy breakfasting off orange juice and
Ryvita biscuits; an unemployed man does not… When you are unemployed you don’t
want
to eat dull wholesome food. You want to eat something a little
tasty
. There is always some cheap pleasant thing to tempt you.”
-- George Orwell, quoted in
Banerjee
and Duflo (Poor Economics)Slide16
16Slide17
Conclusion
17
Tobacco control may not be the right parallel:
While overall smoking has declined, SES disparities have increased
Disparities in obesity rates have narrowed, disparities in health outcomes associated with obesity grown
If
poverty is heart of the concern, weigh benefits and costs of other strategies to improve health
Instead
of food deserts, what about income deserts? Education deserts? Health care deserts?