Ethnic group differences in overweight and obese children and young people in England: cross sectional survey.(ORIGINAL ARTICLE)

Aims: To determine the percentage of children and young adults who are obese or overweight within different ethnic and socioeconomic groups.

Methods: Secondary analysis of data on 5689 children and young adults aged 2-20 years from the 1999 Health Survey for England.

Results: Twenty three per cent of children (n = 1311) were overweight, of whom 6% (n = 358) were obese. More girls than boys were overweight (24% v 22%). Afro-Caribbean girls were more likely to be overweight (odds ratio 1.73, 95% CI 1.29 to 2.33), and Afro-Caribbean and Pakistani girls were more likely to be obese than girls in the general population (odds ratios 2.74 (95% CI 1.74 to 4.31) and 1.71 (95% CI 1.06 to 2.76), respectively). Indian and Pakistani boys were more likely to be overweight (odds ratios 1.55 (95% CI 1.12 to 2.17) and 1.36 (95% CI 1.01 to 1.83), respectively). There were no significant differences in the prevalence of obese and overweight children from different social classes.

Conclusion: The percentage of children and young adults who are obese and overweight differs by ethnic group and sex, but not by social class. British Afro-Caribbean and Pakistani girls have an increased risk of being obese and Indian and Pakistani boys have an increased risk of being overweight than the general population. These individuals may be at greater combined cumulative risk of morbidity and mortality from cardiovascular disease and so may be a priority for initiatives to target groups of children at particular risk of obesity.

Arch Dis Child 2004;89:30-36

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Obesity in children has become a public health problem worldwide and recent trends suggest obesity is also increasing among children in the UK. (1-3) The UK parliament recommended that initiatives to tackle obesity should target schoolchildren, lower socioeconomic groups, and ethnic minorities. (4) There are many immediate harmful physical and psychosocial effects of obesity in children. Long term consequences include increased risks for cardiovascular disease and death that are independent of adult body weight. In the United States, obesity is rising significantly faster among African-American and Hispanic children than any other group. (5 6) Adult British South Asians and Afro-Caribbeans are at increased risk of coronary heart disease and stroke respectively compared with Europeans. A recent report suggested that South Asian children have more biochemical risk factors for cardiovascular disease and a higher insulin resistance than White British children do. (7) Previous studies have reported trends in growth of weight in British children are outstripping that of growth in height in all but Afro-Caribbean ethnic groups. (8) However, defining and measuring overweight and obesity is itself problematic in children. We examined ethnic differences in prevalence of obesity and overweight among children and young adults in the UK using body mass index cut off points as defined by the International Obesity Task Force.

METHODS

The Health Survey for England is an annual survey of people living in private households in England conducted by the National Centre for Social Surveys and Research and University College London on behalf of the Department of Health. The 1999 survey focused on the health of minority ethnic groups. (9)

Sampling and data collection

Three separate samples were obtained (fig 1). Firstly, a general population sample of 6552 households was obtained using two-stage random sampling of postcode sectors and then addresses within each sector. Second, an "ethnic boost" sample of 26 528 addresses was obtained using stratified multistage probability sampling. Additional postcode sectors were selected as primary sampling units. The sampling of postcode sectors was systematic to include a greater proportion from areas with a high percentage of minority ethnic groups. Each household in the ethnic boost sample was screened initially and only included if respondents identified themselves as belonging to an ethnic minority group. A third sample was obtained for Chinese informants by following up 569 households who took part in a Health Education Authority survey in 1998. All participating households were interviewed in full. Individuals selected the most appropriate ethnic group from the categories: "White", "Black, Caribbean", "Black, African", "Black, other", "Indian", "Pakistani", "Bangladeshi", "Chinese", and "Other". Interviewers who could speak and read the respondent's language obtained household, socioeconomic, and personal information, and information on health and health service use. Social class categories, based on occupation of the head of household, were assigned using the Registrar General's classification: I, professional occupations; II, managerial occupations; IIIn, skilled non-manual occupations; IIIm, skilled manual occupations; IV, partly skilled occupations; V, unskilled occupations. Parents or guardians responded for children aged below 13. Children aged 13-15 were interviewed directly with a parent present in the household. A trained nurse took anthropometric measurements including height and weight at a follow up visit soon after the interview according to survey protocols. Quality control was performed on 10% of cooperating households and found to be within acceptable limits for the Health Survey for England.

Method of analysis

We merged individual data from the ethnic boost and Chinese samples with that of the general population sample. We redefined ethnic group categories as: "Afro-Caribbean", "Indian", "Pakistani", "Bangladeshi", "Chinese", and "Irish", and all other ethnic groups together in a baseline group called "general population". We grouped social class into four groups: I & II, IIIn, IIIm, IV & V.

Defining overweight and obesity in children

Adults are defined as overweight if their body mass index (BMI) exceeds 25 kg/[m.sup.2] and …