About this release

This release from Public Health Scotland provides annual statistics on high, low and healthy body mass index (BMI) for Primary 1 school children, and includes data for school years 2001/02 to 2019/20. Statistics in this release are derived from height and weight measurements collected at health reviews in Primary 1.

Main points

  • Coverage of the P1 review fell substantially in 2019/20 to 41%, as height and weight measurements could not take place due to the Covid-19 pandemic. However, the schools which did participate are representative of the whole of Scotland.
Image caption BMI of Primary 1 children, 2019/20
  • In school year 2019/20, around three out of four (76%) Primary 1 children measured had a healthy weight, while more than 1 in 5 (23%) were at risk of overweight or obesity, and 1% were at risk of being underweight.
  • Since 2001/02, the overall proportion of Primary 1 children who are at risk of overweight or obesity has remained fairly constant.
  • However, since 2001/02, inequalities in child unhealthy weight across Scotland have increased. In 2019/20, 27% of children living in the most deprived areas were at risk of overweight or obesity, compared with 17% of children living in the least deprived areas.
  • Boys in Primary 1 have remained slightly less likely than girls to have a healthy weight.


In school year 2019/20 a total of 23,934 children had valid height and weight measurements recorded in Primary 1. This is approximately 41% of all children in Primary 1. Coverage was significantly lower in 2019/20 than in previous years due to the impact of the Covid-19 pandemic, which caused schools in Scotland to close to the majority of pupils. However, the schools which did provide data are representative of Scotland as a whole.

A child’s BMI is calculated by dividing their weight (in kilograms) by their height (in metres) squared. Children are then allocated to a healthy or unhealthy weight category by comparing their BMI to the range of BMIs seen among a reference group of children of the same age and sex. This summary provides information on the proportion of children found to be at risk of having an unhealthy weight based on the thresholds used for monitoring the health of the child population (‘epidemiological thresholds’). The full report also provides information on the proportion of children found to have an unhealthy weight based on the stricter clinical thresholds used by health professionals caring for individual children. There is continued concern over the levels of overweight and obesity among children in Scotland. Obesity during childhood is a health concern in itself, and it can also lead to physical and mental health problems throughout adulthood. Being underweight in childhood can also be a cause for concern, indicating poor nutritional intake and/or underlying medical problems.

Further information

Public Health Scotland publishes a wide range of information on Child Health including infant feeding, immunisations, and early child development. Further information can be found in the Child Health section of the Data and Intelligence website.

The next release of this publication will be December 2021.

General enquiries

If you have an enquiry relating to this publication, please email phs.childhealthstats@phs.scot.

Media enquiries

If you have a media enquiry relating to this publication, please contact the Communications and Engagement team.

Requesting other formats and reporting issues

If you require publications or documents in other formats, please email phs.otherformats@phs.scot.

To report any issues with a publication, please email phs.generalpublications@phs.scot.

Older versions of this publication

Versions of this publication released before 16 March 2020 may be found on the Data and Intelligence, Health Protection Scotland or Improving Health websites.

Last updated: 21 March 2024
Was this page helpful?