The population of obese children and adolescents worldwide has risen tenfold in the past four decades, which has become a global health crisis that threatens to worsen unless drastic actions are taken, the World Health Organization (WHO) warned Wednesday.

On the occasion of World Obesity Day, the WHO and Imperial College London released their latest study on childhood and adolescent obesity worldwide, which was published in the medical journal The Lancet.

It analyzed weight and height measurements from nearly 130 million people aged over five years, including 31.5 million aged five to 19 and 97.4 million aged 20 and older, making it the largest ever number of participants involved in an epidemiological study. Meanwhile, more than 1,000 contributors participated in the study which looked at body mass index and how obesity has changed worldwide from 1975 to 2016.

The figures show that the obesity rates in the world's children and adolescents increased from less than one percent, or some five million girls and six million boys, in 1975 to nearly six percent in girls (50 million) and nearly eight percent in boys (74 million) in 2016. Combined, the number of obese five- to 19-year-olds rose more than tenfold globally, from 11 million in 1975 to 124 million in 2016, while an additional 213 million wereoverweight in 2016 but fell below the threshold for obesity.

"These worryin trends reflect the impact of food marketing and policies across the globe," said Professor Majid Ezzati from the School of Public Health at Imperial College London, who was the study's lead author.

Healthy nutritious foods are becoming too expensive for poor families and communities, he continued, urging for more availability at home and school of these kind of foods, especially in poor families and communities.