Obesity rates in children, adolescents have soared worldwide

By Liz Meszaros, MDLinx
Published October 11, 2017

Key Takeaways

In children aged 5 to 19 years, the incidence of obesity worldwide has increased 10-fold over the past 40 years, according to results published in The Lancet to coincide with World Obesity Day, October 11. 

“Over the past four decades, obesity rates in children and adolescents have soared globally, and continue to do so in low- and middle-income countries. More recently, they have plateaued in higher income countries, although obesity levels remain unacceptably high,” said lead author Majid Ezzati, PhD, chair, Global Environmental Health, School of Public Health, Imperial College London, UK.

Among high-income countries, the US had the highest obesity rates for girls and boys.

For this study—one of the largest epidiomologic studies ever completed—Dr. Ezzati and fellow researchers from Imperial College London and the World Health Organization (WHO) pooled height and weight data from 2,416 population-based studies, comprised of 128.9 million participants aged ≥ 5 years, including 31.5 million aged 5 to 19 years. Using a Bayesian hierarchical model, they estimated trends from 1975 to 2016 in 200 countries for mean BMI and prevalence of BMI for children and adolescents aged 5-19 years for the following:

  • More than 2 standard deviations (SD) below the median of the WHO growth reference (moderate and severe underweight);
  • 2 SD to over 1 SD below the median (mild underweight);
  • 1 SD below the median to 1 SD above the median (healthy weight);
  • More than 1 SD to 2 SD above the median (overweight but not obese);
  • More than 2 SD above the median (obesity).

Obesity rates in the world’s children and adolescents increased from less than 1% (5 million girls, 6 million boys) in 1975, to almost 6% in girls (50 million), and nearly 8% in boys (74 million) in 2016. When combined, the number of obese 5- to 19-year-olds increased more than 10-fold globally, from 11 million in 1975 to 124 million in 2016.

Finally, these researchers found that in 2016, an additional 213 million children were overweight, although below the threshold for obesity.

“These worrying trends reflect the impact of food marketing and policies across the globe, with healthy nutritious foods too expensive for poor families and communities. The trend predicts a generation of children and adolescents growing up obese and at greater risk of diseases, like diabetes,” Dr. Ezzati said.

“We need ways to make healthy, nutritious food more available at home and school, especially in poor families and communities, and regulations and taxes to protect children from unhealthy foods,” he added.

According to Dr. Ezzati and colleagues, if these post-2000 trends continue through 2022, the global levels of child and adolescent obesity will surpass those for moderately and severely underweight youth in this age group.

Despite the worldwide increases in obesity, malnutrition and moderate or severely underweight status in children and adolescents still remains a major public health challenge. In 2016, 75 million girls and 117 million boys were moderately or severely underweight, especially in the poorest countries.

In many middle-income countries, children and adolescents have moved from being mostly underweight to mostly overweight. Such countries include East Asia, Latin American, and the Caribbean. According to Dr. Ezzati and colleagues, this may reflect children’s increased consumption of energy-dense foods, particularly highly processed carbohydrates, which can lead to poor lifelong health outcomes.

“These data highlight, remind and reinforce that overweight and obesity is a global health crisis today, and threatens to worsen in coming years unless we start taking drastic action,” said Fiona Bull, MBE, PhD, MSc, program coordinator for surveillance and population-based prevention of non-communicable diseases (NCDs) for WHO.

“WHO encourages countries to implement efforts to address the environments that today are increasing our children’s chance of obesity. Countries should aim particularly to reduce consumption of cheap, ultra-processed, calorie-dense, nutrient-poor foods. They should also reduce the time children spend on screen-based and sedentary leisure activities by promoting greater participation in physical activity through active recreation and sports,” concluded Dr. Bull.

WHO has published a summary of the Ending Childhood Obesity (ECHO) Implementation Plan, to be released in tandem with the results of this study. The plan provides guidelines on actions that can help mitigate childhood and adolescent obesity. Experts from WHO have also released guidelines calling for frontline health care workers to actively identify and manage children who are overweight or obese.

The number of obese adults increased from 100 million in 1975 (69 million women, 31 million men) to 671 million in 2016 (390 million women, 281 million men). Another 1.3 billion adults were overweight, but fell below the threshold for obesity.

This study was funded by Wellcome Trust and AstraZeneca Young Health Programme.

Share with emailShare to FacebookShare to LinkedInShare to Twitter