Limiting food advertising on TV: estimating the impact on obesity in children

Lennert Veerman

Ed van Beeck

Johan Mackenbach

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Overview

Introduction

Analytical framework

Baseline situation

Exposure -> consumption

Consumption -> mean weight & BMI

BMI -> prevalence overweight

Limitations and sensitivity

Uncertainty in policy

Conclusions

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Introduction

Project on methods for (forecasting in) HIA

Overweight in children increasing

‘Covenant Overweight’

Discussion on role of TV and food advertising

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Study question

What effects on overweight and obesity prevalence among 6 to 12-year

old children can be expected of restrictions on food advertising on TV?

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Analytical framework

Intervention or policy

Exposure to food commercials

Change in mean BMI

Literature, experts, argument

Simulation model

Change prevalence overweight & obesity

Simulation model

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Prevalence overweight

Age

6-12

2003

Boys Overweight (incl. obesity)14.8%

obesity 3.2%

Girls Overweight (incl. obesity)19.4%

obesity 4.1%

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Baseline assessment - BMI distribution

BMI distribution girls aged 11

0.00

0.020.04

0.06

0.08

0.100.12

0.14

0.16

7 9 11 13 15 17 19 21 23 25 27 29

BMI

Fre

qu

ency 1980

1997

2003

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From exposure to consumption

Baseline exposure in NL:

12 minutes of food advertising per week.

Measure of effect needed - by how much does the body weight change

per minute exposure per week?

Only one good quality study gives dose-effect estimate: 1.39% extra

kcal per 25 minutes exposure.

Dutch situation: at zero exposure 0.65% less kcal.

Boys 13 kcal/day, girls 12 kcal/day on average.

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From consumption to weight and BMI

Heavy people need to eat more: 15-25 kcal/day/kg of extra body

weight.

Effect of eating 12-13 kcal less: 0.6 kg body weight, or 0.4 kg/m2.

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From mean BMI to prevalence of overweight

BMI distribution girls aged 11

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

7 9 11 13 15 17 19 21 23 25 27 29

Fre

qu

en

cy

Current No commercials

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Prevalence overweight

Boys

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

20%

Current No advertising 1980

Pre

vale

nce

Girls

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

20%

Current No advertising 1980

Pre

vale

nce

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Results

Reducing exposure of 6-12 year olds to televised food commercials

could reduce the prevalence of overweight by almost 4 %-pt and

reduce the prevalence of obesity by 1 to 1.5 %-pt.

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Limitations & sensitivity

Parameter uncertainty:

Effect measure Bolton

- data from US 1977

- possibly some snacking-while-watching included

Sensitivity (50%, 200%) for effect on overweight M+F: -3.8 (-1.9, -7.4) %-pt

Link kcal-weight based on adults

effect for 25 and 15 kcal/kg: -3.0, -5.0 %-pt

Model uncertainty:

- no time dimension

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Discussion

Step from overweight prevalence to disease and (healthy) life

expectancy could be added

Limiting exposure to food advertising is likely to reduce inequalities

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Uncertainty around effects of policy

Effect of legal measures undercut by

- broadcasting from abroad

- different marketing channels (internet, direct)

Voluntary restrictions by business

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Conclusions

Exposure of children to commercials for (energy dense) food increases their body mass. Current estimate indicates a substantial effect.

Governments, EU and other parties should strive to minimise this exposure in the interest of the (future) health of children.

A monitoring system of both exposure to food advertising and overweight prevalence should be put in place.

Further research could focus on estimating the dose-response relationship, on marketing practices and on policy options for (health) authorities.

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Prevalence overweight

Age

6-12

Current

(2003)

No TV food

ads

1980

Boys Overweight (incl. obesity) 14.8% 11.1% 3.6%

obesity 3.2% 1.9% 0.1%

Girls Overweight (incl. obesity) 19.4% 15.4% 6.9%

obesity 4.1% 2.6% 0.5%