Background Research suggests that there is variation in childhood obesity across ethnic groups in the UK, although findings are inconsistent. The influence of other individual, school and neighbourhood characteristics is not well understood. In addition, patterns may differ geographically. The objectives were to explore the variation in childhood overweight and obesity and BMI across ethnic groups in Coventry, how this compares to other areas, and the influence of additional individual, school and neighbourhood factors.
Methods National Child Measurement Programme data (measuring BMI-for-age against a reference population for reception year and year 6) was combined for 2007/8 to 2014/15 (n = 56,049). Multiple linear regression was conducted in Stata v13 to explore associations between BMI z-score (zBMI) and individual, school and neighbourhood characteristics using local data, with White British as the reference group. Models were fitted with likelihood ratio tests and sensitivity analyses explored the impact of missing data. Neighbourhood was fitted as a random effect in the multi-level model. Prevalence of overweight and obesity by ethnic group for Coventry was compared to local authorities with similar demographics using a Dunnett-type test to adjust for multiple testing.
Results White British children had a mean zBMI of 0.41 (95% CI: 0.39, 0.43) for reception year and 0.51 (0.49, 0.53) for year 6. zBMI for Indian and Chinese children was significantly lower than the reference group for both reception year at −0.09 (−0.14, −0.05) and −0.03 (−0.23, 0.16) and year 6 at 0.37 (0.32, 0.43) and 0.16 (−0.14, 0.46) respectively. Black African children had a higher mean zBMI across both years at 0.58 (0.54, 0.63) and 0.71 (0.68, 0.78) for reception and year 6 respectively. For other ethnic groups, the findings differed by school year. For Bangladeshi children, mean zBMI was significantly lower than the reference group in reception year at 0.24 (0.14, 0.34) yet significantly higher in year 6 at 0.73 (0.61, 0.84). Preliminary results indicate ethnic group differences remain after adjustment for individual, school and neighbourhood factors. The results of multi-level modelling will be presented. Coventry had a similar prevalence of overweight and obese children to Bolton, Derby and Kirklees for all ethnic groups with the exception of Asian children, where Coventry had a significantly higher prevalence.
Conclusion Variation in childhood overweight and obesity and BMI exists across ethnic groups in Coventry, and patterns differ geographically, although analysis is limited by the available data. There is a need for further exploration of the factors driving this variation.