Young people are happier and healthier than their counterparts were a decade ago, according to a new study.

Researchers said a report looking at the health and wellbeing of 11 to 15-year-olds in more than 40 countries across Europe and North America over a 16-year period suggests that while there are still causes for concern, contemporary adolescents are in a better position than past generations.

An increasing proportion of teenagers eat fruit and vegetables, are physically active on a daily basis, keep their teeth clean and rate their health as excellent, research showed.

But, despite this general trend towards healthier eating and healthy lifestyles, the report also found that obesity rates either increased or remained stable at already high levels, between 2002 and 2010.

The study, part of a collaboration with the World Health Organisation (WHO) co-ordinated internationally by the University of St Andrews, said there was a decline in young people experiencing bullying and drinking alcohol weekly, with increasing numbers living free from tobacco and cannabis.

The researchers behind the study warn that despite the generally positive findings, many - if not the majority - of adolescents living in Europe and North America still do not meet the recommendations for healthy living.

In Scotland, the Czech Republic, Denmark, Italy, Lithuania, Russia, Slovenia, Switzerland and the US fewer young people were physically active on a daily basis in 2010 than 2002.

Professor Candace Currie, the international co-ordinator of the study and professor of child and adolescent health at the University of St Andrews, said the research was "a vital source of information for policy-makers, parents and young people themselves".

She said: "Adolescence is a crucial stage in life when you lay the foundation for adulthood, whether that's healthy or otherwise.

"While there is much to celebrate about the health and well-being of many young people today, others continue to experience real and worrying problems.

"Evidence like the papers in this supplement give policy-makers an opportunity to act to secure the health of the next generation."

The special report on trends is a collection of in-depth studies of comparable data on a wide range of topics, from multiple countries and repeated surveys of school children between 1994 and 2010.

The supplement, published today by the European Journal of Public Health, pulls together 20 papers from researchers taking part in the study.

They describe how trends can be interpreted when looking at patterns and differences between countries, across areas such as eating habits, obesity, physical activity and bullying.

Prof Currie added: "By comparing today's young people with their counterparts a decade ago we can better understand how their health is influenced by the circumstances in which they live; access to care, schools and recreational facilities; and their homes, towns and communities. This is a vital source of information."

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