Publication, Part of National Child Measurement Programme
National Child Measurement Programme, England, 2022/23 School Year
Official statistics, National statistics, Accredited official statistics
Introduction
The NCMP is a key element of the Government’s approach to tackling childhood obesity by annually measuring over one million children and providing reliable data on the rates of children living with obesity. Children are measured in reception (aged 4–5 years) and year 6 (aged 10–11 years) in mainstream state-maintained schools in England. Independent and special schools are excluded. See “Coverage” in appendix B for more details.
The programme was launched in the 2005/06 academic year and now holds seventeen years of reliable data. 2006/07 is the first year that the data are considered to be robust due to the low participation in 2005/06.
NCMP data enables local areas to plan services to tackle childhood obesity and monitor progress.
In most local authorities, parents also receive feedback on their child’s weight status along with the offer of further advice and support on achieving a healthy weight for their child.
There is public health concern about the rise of childhood obesity in England and the implications of obesity persisting into adulthood. Obesity in adults is a risk factor for other health conditions such as type 2 diabetes, coronary heart disease, stroke and some types of cancer and may also impact on mental health.
This report contains analysis of the 2022/23 data showing Body Mass Index (BMI) category prevalence with breakdowns by: child age and sex; local authority and region; levels of deprivation; urban/rural classification; ethnicity and ONS area classification. The report contains comparisons over time. It is accompanied by:
- Data tables, including 95 per cent confidence intervals which should be considered when interpreting results.
- Technical appendices with information on data collection, validation, confidence intervals, statistical testing and the methodology used for BMI classification rates.
Geographical analyses in this report are primarily based on the postcode of the child’s home address which is mapped to a lower super output area. Some time series analyses use the school postcode as the child postcode was poorly populated in the early years of the NCMP and these are labelled in the report.
Definitions used
The BMI category of each child is derived by calculating the child’s BMI centile and assigning as follows:
- BMI centile <=2: Underweight
- BMI centile >2 and <85: Healthy weight
- BMI centile >=85 and <95: Overweight
- BMI centile >=95 (between 95 and 100): Obesity
- BMI centile >=99.6 (between 99.6 and 100): Severe obesity. Note: this is a subset of “Obesity”.
This calculation uses age and sex as well as height and weight to take into account different growth patterns in boys and girls at different ages.
A child’s BMI centile is a measure of how far a child’s BMI is above or below the average BMI value for their age and sex in a reference population.
The NCMP uses the population monitoring cut offs of the British 1990 (UK1990) growth reference data to define the BMI categories. These cut offs are based on the assumption that around 15% of the baseline population were overweight and 5% were living with obesity in 1990. This approach is recommended by the National Institute for Health and Care Excellence (NICE). The population monitoring cut offs for overweight and obesity are lower than the clinical cut offs (91st centile for overweight and 98th centile for obesity) used to assess individual children; this is to capture children in the population in the clinical overweight or obesity BMI categories and those who are at high risk of moving into the clinical overweight or clinical obesity categories. This helps ensure that adequate services are planned and delivered for the whole population.
The prevalence of children in a BMI category is calculated by dividing the number of children in that BMI classification by the total number of children and multiplying the result by 100. See “Calculation of prevalence” in appendix C for more details. In this report, the terms "prevalence" and "proportion" are used to state the percentage of children in a BMI category. Although they are used in different areas of the report, these terms have the same meaning.
Comparisons between groups and over time have been statistically tested to determine whether differences are likely to be genuine (i.e. statistically significant) or the result of random natural variation. Only statistically significant differences have been described with terms such as “higher”, “lower”, “increase” or “decrease”. When a comparison does not show a statistically significant difference, this will be described using terms such as “similar to” or “the same as".
Last edited: 19 October 2023 12:42 pm