Page last updated: 18-DEC-2007

The World Health Organisation has acknowledged that obesity is sweeping the world and is a major public health problem.  Of particular concern is the increasing incidence of child obesity.  Being overweight or obese during childhood is a health concern in itself, but can also lead to physical and mental health problems in later life, such as heart disease, diabetes, osteoarthritis, back pain, increased risk of cancer, low self-esteem and depression.

 

All NHS Boards in Scotland provide a Child Health Surveillance Programme where children are offered routine reviews at various stages of their life. The majority of Boards record these reviews using the Child Health Systems Project (CHSP). This release updates statistics on high and low body mass index (BMI) for Primary 1 school children, derived from height and weight measurements collected at routine health reviews through the CHSP-School.  BMI assesses whether weight is in proportion to height and therefore gives an indication of body "fatness" or "thinness".  As CHSP-School is implemented in the majority of NHS Boards, data from this system can be used to estimate prevalence of over and under weight children in Scotland.
  
In adults, BMI can be directly classified into different categories (e.g. underweight, normal, overweight, obese) since age in adulthood doesn't greatly affect weight in relation to height. However, these adult BMI category cut-offs aren't appropriate for children since BMI changes markedly as a child ages. A certain BMI at one age may be the norm but for another age the same BMI may be unusually high or low (indicating that the child is overweight or underweight). Instead, for children, BMI can be converted into centiles, using reference data based on sex and age. These centiles can then be used to categorise BMI e.g. > =95th centile indicates obesity.

 

Statistics in this release are derived from centiles, using the 1990 UK growth reference standards. These growth reference charts are based on data collected between 1978 and 1990 from UK surveys (they therefore represent children’s weight relative to height before the recent rise in levels of obesity in children). Cut-off points based on these studies define overweight as children whose BMI is in the top 15% of the reference range for their age and sex. Obese and severely obese children are defined as those whose BMI is in the top 5% and 2% of the reference range respectively.

 

The release updates annual statistics on high and low body mass index (BMI) for Primary 1 school children and includes data to school year 2006/07.  The statistics are derived from data provided by nine NHS Boards in Scotland, and is presented by : participating NHS Board, Community Health Partnership, gender and Scottish Index of Multiple Deprivation (SIMD) quintile.

Using the 1990 UK growth reference standard for BMI, in 2006/07, 21.0% of Primary 1 school children were overweight, including 8.5% who were obese and 4.3% who were severely obese. 

 

Although levels of high BMI decreased slightly from 2005/06 (22.0% overweight, including 9.1% obese and 4.4% severely obese) to 2006/07, overall, levels have gradually increased from those for 2000/01 (19.7% overweight, including 8.0% obese and 3.9% severely obese).

For epidemiological purposes, an individual BMI is not meaningful in isolation, only in the context of the distribution of values for a population. Individual children can be assigned to categories (e.g. overweight) using centiles derived from their BMI to gauge where they lie in the population - in particular, whether they have an unusually high or low BMI. Children with a BMI within the 5th -  85th centile range are considered to be in the normal range (although BMI may incorrectly categorise a small minority of children with heavy musculature as being overweight or obese).

 

Statistics in this release are derived from centiles, using the 1990 UK reference standards. These growth reference charts are based on data collected between 1978 and 1990 from UK surveys (they therefore represent children's weight relative to height before the recent rise in levels of obesity in children). Cut-offs points based on these studies define overweight as children whose BMI is in the top 15% of the reference range for their age and sex. Obese and severely obese children are defined as those whose BMI is in the top 5% and 2% of the reference range respectively.

 

CHSP-School is implemented in the majority of NHS Boards and data from this system have been used to derive the statistics in this release (data for NHS Grampian, NHS Ayrshire and Arran, NHS Orkney, NHS Shetland, NHS Highland and the former NHS Greater Glasgow are not included).

 

Figures for Community Health Partnerships and NHS Boards with small numbers of reviews should be interpreted with care as the small numbers may result in fluctuations in the percentages from year to year etc. The smaller the number of reviews, the poorer the precision of the estimate (percentage) and the wider the associated confidence interval.  

1. Using the 1990 UK growth reference standards, in 2006/07, 21.0% of children in Primary 1 were overweight, including 8.5% who were obese and 4.3% who were severely obese. Although levels of high BMI decreased slightly from 2005/06 (22.0% overweight, including 9.1% obese and 4.4% severely obese) to 2006/07, overall, levels have gradually increased from those for 2000/01 (19.7% overweight, including 8.0% obese and 3.9% severely obese).

 

2.  In Primary 1, levels of high BMI amongst boys tend to be slightly higher than those for girls.  In school year 2006/07, 22.0% of boys were overweight (including 9.0% obese and 4.4% severely obese) compared to 20.1% of girls (including 8.0% obese and 4.1% severely obese).

 

3. Primary 1 figures for 2006/07 indicate that the highest levels of overweight, obese and severely obese children are found in the most deprived areas (22.5% overweight, including 9.9% obese and 5.5% severely obese) while children in the least deprived areas had the lowest levels (18.8% overweight, including 7.2% obese and 3.1% severely obese) however, this pattern is not clearly observed for previous years.

 

4. The percentage of Primary 1 school children with low BMI was 3.0% in 2006/07, which is lower than the 1990 UK reference standard of 5%.

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BMI: Body Mass Index

CHSP-PS: Child Health Systems Project - Pre-School

CHSP-S: Child Health Systems Project - School

Hall4: Health For All Children 4 - Guidance on Implementation in Scotland

 

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Scottish Executive Health Directorates
Directors of Public Health
Child Health Systems Project Board and National User Group Chairs
NHS Board Chief Executives

 

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