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The Key Data series has been running since 1997, providing nearly 25 years of information about young people’s lives. Previous editions have been hard copies or on-line PDFs; since 2021 we have presented it as a website.

Key Data collates publicly available data, extracting what we can find that is directly relevant to the 10-25 age group. The information is organised by topic. Click on different themes to get an overview, key findings and links to more information. You can also use the search function to find information on different topics.

We’re very interested in what you think of this as a resource, or any information you might have about additional data sources that might be relevant. Please do email us at any time with comments, suggestions and feedback, or complete our feedback survey.

KDYP - Overview and policy implications

Overview and policy implications

The following pages provide a host of data on different aspects of young people’s health over recent years. 

To accompany the website and to highlight the main themes and ‘take home’ messages we have prepared an ‘Overview and Policy Implications’, which is downloadable as a PDF.

Key Data on Young People 2021 Webinar

Key Data on Young People 2021 was launched at an online webinar. The webinar included a presentation of the main findings by AYPH’s Research Lead Dr Ann Hagell, and responses from paediatrician, Dr Lizzie Wortley and one of our youth interns, Jose Vinaixa Kinnear. You can watch a recording of the event here. 


Population size and mortality

Population size and mortality

Children and young people aged 10-24 account for 18% of the population of the UK.  The most common causes of death include accidents, self-harm and assault, and cancer.

Public Health Outcomes

Public health outcomes

In this section we present data for some of the public health outcomes that are most relevant to young people 10-24, particularly those relating to health behaviours.  Separate sections present data on life expectancy, mental health and sexual health.

Sexual health and identity

Sexual health and identity

Presenting data on young people’s sexual behaviour and how they identify.  Sections include what age young people start to have sexual relationships; contraception use; conception and birth rates for young parents; and sexually transmitted diseases.

Physical health conditions

Physical health conditions

Although the years 10-24 tend to be a time of good physical health, many young people will experience a range of short term physical health problems. A significant minority will have long-term chronic conditions or some kind of disability.



Neurodiversity describes the learning and thinking differences that young people may have, including autism, attention deficit and hyperactivity disorder (ADHD), and special educational needs.

Mental Health

Mental health

Some of the most common mental disorders experienced by young people include anxiety disorders, mood disorders, behavioural disorders and eating disorders. Mental health problems have important implications for all aspects of young people’s lives.

Use of Health Services

Use of health services

Good outcomes for young people rely on youth friendly health services – from community based health promotion through to NHS inpatient care.

One in five people experiences at least one form of child abuse before the age of 16

Background factors: Abuse and trauma

The unique nature of adolescence means that young people experiencing abuse and trauma in this phase of life may have different needs to younger children or adults.

One in five secondary school aged children are  eligible for free school meals

Background factors: Living circumstances

The UK’s young people between the ages of 10 and 25 experience a range of different living circumstances and economic challenges, which are important for their health.

In England 29.4% of 18 year olds started university in 2019

Background factors: Education and employment

Young people’s experiences of education, training and employment provide an important context for understanding their health outcomes, both now and in the future.