Dr S Saxena 1 Dr G Ambler 2 Prof. TJ Cole 3 Prof A. Majeed 1

1. Ethnic differences in obesity in British children Dr S Saxena1 Dr G Ambler2 Prof. TJ Cole3 Prof A. Majeed1 1Imperial College London, 2UCLH Trust, 3Institute of Child Health

2. England and Scotland have one of the fastest growing obesity rates in the world….more than doubled between 1980 and the early nineties...(2001 figures) show 21% of men and 23.5% of women over 16 years have a Body Mass Index of 30 or more in England.

3. Background • Obesity epidemic world wide • US rising faster in African-Americans • British South Asians & Afro-Caribbean adults at risk of cardiac disease • British South Asian children have worse biochemical risk profiles for cardiac disease

4. Interrelationships Black Caribbean S. Asian ethnicity Obesity ? Diabetes Cardiovascular disease

5. Aims To compare the percentage of obese or overweight children within different ethnic and socio-economic groups

6. Health Survey for England1999 • Annual cross sectional survey • Focus on ethnic minority groups • Random sampling of private households • Interview & nurse visit for measurements

7. Sampling Random sampling Systematic sampling postcode sectors General Population n=6552 Ethnic boost n=3891 household screening “Core” general pop n=2061 Ethnic groups n=354 Ethnic groups n=4857 Chinese n=342

8. Ethnic group categories in HSE99 ETHNIC GROUPS COMPARED ‘General population’ ‘Irish’ ‘Afro-Caribbean’ ‘Indian’ ‘Pakistani’ ‘Bangladeshi’ ‘Chinese’

9. Measure Body Mass Index height 2 BMI = weight / (m) (kg/m2) (kg)

10. Defining obesity in children Adults overweight: BMI  25 kg/m2 obese: BMI  30 kg/m2* • In children, BMI rapidly changes with age • In US,85th and 95th centile for OW and OB* • UK growth reference charts adopt this# *US reference population # UK growth reference charts (1991)

11. IOTF standard 2000 Overweight Obesity

12. % Response rates Gen Pop Ethnic boost Household 76 71 Interview 97 92-96 Nurse visit 89 86

13. Results : Socio-economic status of ethnic groups Social Ethnicity class G.Pop AC Ind Pak Bang Chin Irish I+II34 22 28 18 9 37 39 IIIn 13 22 10 6 7 16 15 IIIm 31 22 30 40 35 31 29 IV+V 20 28 28 23 33 10 16

14. Results : Socio-economic status of ethnic groups Social Ethnicity class G.Pop AC Ind Pak Bang Chin Irish I+II 34 22 28 18 9 37 39 IIIn 13 22 10 6 7 16 15 IIIm 31 22 30 40 35 31 29 IV+V 20 28 28 23 33 10 16

15. Risk of being overweight in girls by social class Social class

16. Risk of being overweight in boys by social class Social class

17. Risk overweight in boys by ethnic group Adjusted odds ratio Ethnic group

18. Risk overweight in girls by ethnic group Adjusted odds ratio Ethnic group

19. Risk of obesity in boys by ethnic group Adjusted odds ratio Ethnic group

20. Risk of obesity in girls by ethnic group Adjusted odds ratio Ethnic group

21. Strengths of study Power: Large Representative:Population based study Measure: Objective (BMI)

22. Ethnic group comparisons: limitations • Different heights for same BMI • Different fat composition for same BMI • Ethnic group reported by parent • Data cross sectional

23. Conclusions • Ethnicity strong determinant of obesity in children • British Afro-Caribbean & Pakistani girls at increased risk of obesity • Indian and Pakistani boys more likely to be overweight • Social class differences do not contribute to obesity in children

24. Possible explanations

25. Future studies • Longitudinal studies for cumulative risk • Develop standards for child obesity • Include ethnicity in assessing cardiac risk