NEIGHBORHOOD FOOD AVAILABILITY, DISPARITIES, AND CHILDHOOD OBESITY RISK

Helen LeeSenior Research Associate, MDRChelen.lee@mdrc.org

2

Scientists Sound the Alarm on Obesity Early

“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 obese

3

Despite Warnings, Obesity Rates Rise Dramatically

1971-1974 1976-1980 1988-1994 1999-2000 2003-20060

2

4

6

8

10

12

14

16

18

20

Aged 2-5

Aged 6-11

Aged 12-19Per

cen

t O

bes

e

SOURCE: National Health and Nutrition Examination Surveys (NHANES)

Childhood Obesity Prevalence Rates

4

And Disparities are Large

White Black Hispanic0

5

10

15

20

25

30

Obese, kindergartenObese, 5th grade

Less than high

school

High school/

GED

Some college

College or higher

0

5

10

15

20

25

30

Obese, kindergartenObese, 5th grade

Percent obese by race/ethnicity

Percent obese by maternal education

SOURCE: Early Childhood Longitudinal Study – Kindergarten Cohort (ECLS-K), 1999 and 2004

5

Concerns Are Multi-faceted, but Framing Becomes Simplified

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 culprits Advertising and media exposure Supersizing of the food industry Agri-business (e.g., high fructose corn syrup) Pricing policy

6

Policymakers Respond

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 efforts to decrease exposure to “toxic” vendors L.A.’s fast food establishment moratorium in South

Central NYC’s super-size soda ban

7

8

But Empirical Foundation and Evidence is Inconclusive…

Research Questions:1) Are there distinct patterns in food

access by neighborhood poverty and race?

2) Do differences in residential food availability explain obesity risk over young childhood?

Do they explain disparities?

9

Merged Individual Data on Children with Neighborhood Food Establishments

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 5th 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 vendors

10

Key Measures

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, supercenters

Corner grocery stores Grocery stores operated by 3 employees or less

Convenience 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)

11

Large grocery store

Corner store Convenience store

Fast-food chain0

1

2

3

4

5

6 White Black Hispanic Mixed

Nu

mb

er

of s

tore

s p

er

squ

are

mile

*

*

*

*

*

* *

Minority Neighborhoods Have Higher Concentrations of Various Food Vendors

SOURCE: NETS 2006 and Census 2000NOTES: 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).

* *

**

12

Poorer Areas Do Not Have Worse Access to Healthy Food Stores

Large grocery store

Corner store Convenience store Fast-food chain0

2

4

6

8

10

12

Non-poor Poor Very poor

Nu

mb

er

of s

tore

s p

er

squ

are

mile

*

*

* * * *

*

SOURCE: NETS 2006 and Census 2000NOTES: 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).

13

How One Measures Food Environments Might Matter

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%

14

Null Findings for Food Availability and Child Weight OutcomesFood availability (density per square mile)

Coef P<value

Associations with BMI percentile at baseline

Supermarkets 0.37 0.38Corner stores 0.07 0.46Convenience stores 0.08 0.61All other restaurants 0.01 0.73Fast food outlets 0.16 0.44

Associations between change 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 5th grade panel, 1999-2004, and NETS, 1998-2004NOTES: 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 estimates 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.

15

Implications

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)

16

17

Conclusion

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?