Socioeconomic Inequalities in Childhood Obesity in Ireland Brendan Walsh & John Cullinan

Socioeconomic Inequalities in

Childhood Obesity in Ireland

1

Brendan Walsh

a

& John Cullinan

b a HRB/NCI Fellow in Health Economics, NUI Galway b Cairnes School of Business and Economics, NUI Galway

The Obesity Problem, NUI Galway 17 th January 2014

Obesity in Ireland

2

 Approximately 18% of adults obese in Ireland

 44% of the diabetes burden, 23% of the ischemic heart disease burden and between 7% and 41% of the burden of certain cancers can be attributed to overweight and obesity

 Obesity accounts for 21% of health spending in the US

Childhood Obesity

3

 Whelton et al. (2007) found 6% of children in the Republic of Ireland and

Northern Ireland were obese

 Layte et al. (2011) found that 19% of 9 year old children in Ireland were overweight , while 7% were obese

 Joint Oireachtas Committee has highlighted the problem of obesity in children

(April 2012)

 Obesity related problems amongst children cost the health service in the US as much as $14.1 billion annually


4

 While studies have shown a reduction or levelling off of obesity rates amongst children, these reductions mainly occurred in the highest SES groups



Thus the importance of socioeconomic inequalities may be actually increasing in this context


5

 While studies have shown a reduction or levelling off of obesity rates amongst children, these reductions mainly occurred in the highest SES groups






Probability of adult obesity (BMI>30):



If a Recommended Weight child – 15 %


6

 While studies have shown a reduction or levelling off of obesity rates amongst children, these reductions mainly occurred in the highest SES groups.









If a Recommended Weight child – 15%



If an Overweight/Obese child– 65 %


7

 While studies have shown a reduction or levelling off of obesity rates amongst children, these reductions mainly occurred in the highest SES groups.









If a Recommended Weight child – 15%



If an Overweight/Obese child– 65%



If an Obese child– 82%

Question!

8

Is there a Socioeconomic Gradient in

Childhood Obesity?

Question!

9



Yes!

Layte et al., (2011) in Ireland

Knai et al., (2012) in Europe

Stamakis et al., (2010) in England

Singh et al., (2008) in the United States

Childhood Obesity Across Mother’s BMI

10

Overall Mother

Recommended

Overall 5.34% 2.14%

Mother

Overweight

6.65%

Mother Obese

11.74%

Childhood Obesity Across Household’s Income

11

Overall

Overall 5.34%

Income1

7.43%

(Lowest)

Income 2 5.34%

Income 3 6.08 %

Income 4 4.92 %

Income5

(Highest)

2.92 %

Childhood Obesity Across Household’s Income and Mother’s BMI

12

Mother Obese Overall Mother

Recommended

Overall 5.34% 2.14%

Income1

7.43%

(Lowest)

Income 2 5.34%

2.99%

2.23%

Income 3 6.08 % 2.66%

Income 4 4.92 % 2.29%

Income5

(Highest)

2.92 %

0.93

%

Mother

Overweight

6.65%

8.88%

6.89%

5.87%

6.40%

5.67%

11.74%

14.04

%

9.96%

14.95%

9.87%

7.05%

Childhood Obesity Across Household’s Social

Class and Mother’s BMI

13

Mother Obese

Overall

SEG 5

(Lowest)

SEG 4

Overall Mother

Recommended

5.34% 2.14%

9.16% 2.88%

SEG 3

7.35%

6.22%

2.32%

2.97%

SEG 2 4.31% 2.23%

SEG 1

(Highest)

2.29% 0.34%

Mother

Overweight

6.65%

10.69%

9.67%

5.41%

6.12%

3.70%

11.74%

17.78%

13.30%

14.09%

7.57%

7.69%

Methods

14

 Growing Up in Ireland (GUI): Survey of 8,568 (14%) of 9-year-olds in Ireland with information concerning children, their care givers, teachers and school principals

 Obesity classified on basis of International Obesity Taskforce (IOTF) 95 th percentile for children aged 9 years and 6 months, while the overweight cut-off used is the IOTF 85 th percentile



The IOTF may allow for a greater distinction between weight caused by body fat and muscle

 GUI measures height and weight of children and parents/caregivers.

Concentration Indices

15

 Measures the Concentration of obesity across the income distribution.



Is Childhood obesity concentrated in the poorer households or richer households

 Equivalised Household Income used as the Ranking Variable





Takes the number of people living in the household into account

Use a Wagstaff normalisation for the binary (obese or not) nature of the dependent variable


16

 Measures the Concentration of obesity across the income distribution.



Is Childhood obesity concentrated in the poorer households or richer households

 Equivalised Household Income used as the Ranking Variable







Takes the number of people living in the household into account

Use a Wagstaff normalisation for the binary (obese or not) nature of the dependent variable



Example : Medical Card (Medicaid in the US)

Medical Cards are more concentrated among poorer households


17



Interpretation:



The concentration index (CI) quantifies the inequality in a measure that ranges between -1 (pro-poor) and +1 (pro-rich) , with zero representing perfect equality. (Medical Card has a CI<0)





A CI of -0.10

 means a redistribution of 10% of the health from the poorest half of the distribution to the richest half to allow perfect equality

A CI of -0.20 illustrates twice as much inequality as a CI of -0.10

Decomposition

18







Decomposition allows for greater information regarding what is contributes to the inequality. Uses a range of variable which impact upon childhood obesity and/or income

 Has 2 parts

1) Elasticity . Change in Obesity for a given change in the independent variable.

2) Concentration . Distribution of the independent variable across income

Decomposition

19










 Has 2 parts



Contribution= Elasticity*Concentration

Decomposition

20












 Has 2 parts



Contribution= Elasticity*Concentration

Percentage Contribution estimates the percentage of the inequality determined by the contribution.

Decomposition

21







Example:

Childhood obesity may be disproportionally distributed among poorer households due to Parental BMI .

Parental BMI may be





Correlated with Childhood Obesity ( Elasticity ) and,

Concentrated disproportionally among poorer households ( Concentration )

Decomposition thus allows for the contribution of Parental

BMI on inequality in childhood obesity to be estimated. Income itself may not be driving observed inequalities.

Overall

Obese

Overweight

Recommended

Weight

Underweight

Results

22

Percentages

100%

5.34%

18.81%

68.73%

7.12%

Sample Size

8,599

370

1,303

4,760

493

Descriptive Statistics

Obese

5.34% Overall

Household Income

1st quintile ( Poorest )

2 nd quintile

3 rd quintile

4 th quintile

5 th quintile ( Richest )

Socioeconomic Group

Socioeconomic Group 1





Mother’s Education

Degree or above

Upper secondary

Lower secondary Below

Mother’s BMI

BMI<=24.99

BMI 25-29.99

BMI 30 and above

7.43%

5.34%

6.08 %

4.92 %

2.92 %

1.99%

4.39 %

6.31 %

7.30 %

8.25 %

2.67%

5.60 %

8.60%

2.14%

6.65 %

11.74 %

23


Obese

5.34% Overall



2 nd quintile

3 rd quintile

2.54 times larger

4 th quintile









Degree or above

Upper secondary


Mother’s BMI

BMI<=24.99

BMI 25-29.99

BMI 30 and above

7.43%

5.34%

6.08 %

4.92 %

2.92 %

1.99%

4.39 %

6.31 %

7.30 %

8.25 %

2.67%

5.60 %

8.60%

2.14%

6.65 %

11.74 %

24


Obese

5.34% Overall



2 nd quintile

3 rd quintile

4 th quintile









Degree or above

Upper secondary


Mother’s BMI

BMI<=24.99

BMI 25-29.99

BMI 30 and above

7.43%

5.34%

6.08 %

4.92 %

2.92 %

1.99%

4.39 %

6.31 %

7.30 %

8.25 %

2.67%

5.60 %

8.60%

2.14%

6.65 %

11.74 %

25


Obese

5.34% Overall



2 nd quintile

3 rd quintile

4 th quintile









Degree or above

Upper secondary


Mother’s BMI

BMI<=24.99

BMI 25-29.99

BMI 30 and above

5.5 times larger

7.43%

5.34%

6.08 %

4.92 %

2.92 %

1.99%

4.39 %

6.31 %

7.30 %

8.25 %

2.67%

5.60 %

8.60%

2.14%

6.65 %

11.74 %

26

Question!

27




28

Concentration index

Standard error

T value

Obese

-0.1680***

0.0298

-5.6375





Wagstaff Normalised Concentration Indices

Standard Errors are corrected for autocorrelation and heteroskedasticity

Overweight/Obese

-0.0570***

0.0111

-5.1351

Decomposition

29

 Variables partitioned into 4 groups



Socioeconomic Variables, Parental Level Variables, Household Level Variables,

Childhood Level Variables

Decomposition

30





Variables partitioned into 4 groups





Socioeconomic : Social Class, Parental Education

Decomposition

31













Parental Level Variables: Parents Age, BMI, Smoking Status, Alcohol

Consumption, Breastfeeding

Decomposition

32

















Household Level Variables: Urban/Rural, Own Home, Access to

Grocery Stores and Recreational Activity

Decomposition

33



















Household Level Variables: Urban/Rural, Own Home, Access to

Grocery Stores and Recreational Activity

Childhood Level Variables: Gender, Child Health, Doctor/Hospital

Visits, TV, Reading, Video Games, Pocket Money, Diet, Junk Food, Soda,

Physical Activity, Birth weight

Decomposition Results For Obesity

Contribution

0.016

Percentage Contribution

-9.49% Ln(Income)

Socioeconomic Variables






Mother’s Educ: Degree or above

Mother’s Educ: Upper secondary

Mother’s Educ: Lower

Socioeconomic Overall

Parental Level Variables

Mother’s BMI

Mother’s Smoking Status

Mother’s Alcohol Status

Breastfed

Overall

Household Level Variables

Overall

Child-Level Variables

Overall

Base

0.029

-0.010

-0.020

-0.044

Base

-0.004

-0.021

-0.070

-0.040

-0.013

-0.001

-0.004

-0.058

0.003

-0.028

-

-17.47%

6.09%

11.61%

26.14%

-

2.25%

12.24%

41.16%

23.78%

7.41%

0.49%

2.45%

34.13%

-1.48%

16.25%

34

Decomposition Results For Obesity

Contribution

0.016

Percentage Contribution

-9.49% Ln(Income)

Socioeconomic Variables






Mother’s Educ: Degree or above

Mother’s Educ: Upper secondary

Mother’s Educ: Lower

Socioeconomic Overall

Parental Level Variables

Mother’s BMI

Mother’s Smoking Status

Mother’s Alcohol Status

Breastfed

Overall

Household Level Variables

Overall

Child-Level Variables

Overall

Base

0.029

-0.010

-0.020

-0.044

Base

-0.004

-0.021

-0.070

-0.040

-0.013

-0.001

-0.004

-0.058

0.003

-0.028

-

-17.47%

6.09%

11.61%

26.14%

-

2.25%

12.24%

41.16%

23.78%

7.41%

0.49%

2.45%

34.13%

-1.48%

16.25% 35

Conclusions

36

 This study presents, for the first time, concentration indices of obesity (CI=-

0.168) and overweight/obese (CI=-0.057) for Irish children

 Inequalities in Childhood Obesity are larger than has been seen in adults (Madden,

2013)

 Results highlight that a socioeconomic gradient exists, but this gradient is likely to have manifested in a complex, multilevel manner.

 The determinants of childhood obesity is clearly a multifaceted problem which does not have a simple solution

Decomposing Socioeconomic

Inequalities in Childhood

Obesity: Evidence from Ireland

37

Thank You

Socioeconomic Inequalities in Childhood Obesity in Ireland Brendan Walsh & John Cullinan

Socioeconomic Inequalities in

Childhood Obesity in Ireland

Brendan Walsh

& John Cullinan

Childhood Obesity Across Mother’s BMI

Childhood Obesity Across Household’s Income

Childhood Obesity Across Household’s Income and Mother’s BMI

Childhood Obesity Across Household’s Social

Class and Mother’s BMI

Interpretation:

Example:

Percentages

Sample Size

Decomposing Socioeconomic

Inequalities in Childhood

Obesity: Evidence from Ireland

Thank You

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Socioeconomic Inequalities in Childhood Obesity in Ireland Brendan Walsh &amp; John Cullinan