Obesity Soars 10-Fold in Kids; With Underweight It's a 'Double Burden'

Becky McCall

October 11, 2017

Obesity among children and adolescents has risen 10-fold worldwide in the past 4 decades, new research published in the Lancet to coincide with World Obesity Day reveals.

In addition, childhood obesity is expected to exceed underweight within 5 years (2022) in many developing countries, leading to a "double burden," whereby some countries struggle with both underweight and obesity.

Described by the lead author as the most comprehensive analysis of child and adolescent weight ever conducted, the novel study analyzed mean body mass index (BMI) among children and adolescents (5–19 years) across 200 countries, between 1975 and 2016.

The findings also provide a complete picture of categories from underweight through to obese, and these trends were compared with those of adults.

Majid Ezzati, PhD, chair in global environmental health, Imperial College London, United Kingdom, led the study on behalf of the NCD Risk Factor Collaboration and reported the top-line results at a press briefing in London yesterday.

"There has been a 10-fold increase in the number of obese children in the world [over the past 40 years], so that nearly one in five children are overweight or obese worldwide today," he announced.

High-income countries showed a plateauing of mean BMI in the 5- to 19-years age group, albeit at high levels since 2000, but this contrasted with an increase in the mean BMI of adults and in levels of overweight and obesity that have "accelerated in East, South, and Southeast Asia," he stressed.

At the present time, it's still important to note that this rise in obesity in certain regions of the world contrasts with the finding that, globally, there are still more children and adolescents who are moderately or severely underweight than obese, explained Dr Ezzati.

"However, if post-2000 trends continue, child and adolescent obesity is expected to surpass moderate and severe underweight by 2022."

Writing in an accompanying editorial with reference to this forecast, William H Dietz, MD, from Milken Institute School of Public Health, George Washington University, Washington, DC, stressed that "a double burden of nutritional disease now exists in many regions of the world, such as the Middle East and north Africa."

"This double burden…adds an additional layer of complexity but raises the possibility that double-duty actions could simultaneously reduce obesity and undernutrition," he stresses.

But further research is needed to understand whether the factors that affect undernutrition are similar to those that foster obesity in a particular population, he added.

Data from 200 Countries Documents Global Rise in Childhood Obesity

An unprecedented amount of population-based data were analyzed in this latest study, drawn from almost all of the world's countries. Weight and height measurements from the largest number of participants ever involved in an epidemiological study — nearly 130 million people aged over 5 (31.5 million people aged 5 to 19 and 97.4 million aged 20 and older) were used, "while maintaining a high standard of data quality and using only measured height and weight information to avoid the bias in self-reported data," the authors explain.

In total, 2416 population-based studies were mined for the current analysis of trends in mean BMI and categories of BMI in children and adolescents over a 40-year period from 1975. The categories were moderate and severe underweight, mild underweight, healthy weight, overweight but not obese, and obese.

The worldwide 10-fold rise in obesity over the past 4 decades has been seen in both sexes, with an increase from five million in 1975 to 50 million in 2016 in girls and from six million to 74 million in boys, respectively.

Rates of child and adolescent obesity were highest (above 30%) in some islands in Polynesia and Micronesia, which showed an increase of 0.77 kg/m2 per decade; rates were around 20% or higher in the United States and some countries in the Middle East and North Africa, notably, Egypt, Kuwait, Qatar, and Saudi Arabia; as well as in the Caribbean, including Bermuda and Puerto Rico.

Overall, the global prevalence of child and adolescent obesity increased from 0.7% to 5.6% for girls, and from 0.9% to 7.8% for boys. The rise in BMI has also accelerated in East and South Asia for both sexes and in Southeast Asia for boys.

"In Polynesia and Micronesia, nearly 50% of children are overweight/obese," Dr Ezzati told the London press briefing.

"The same is true in India, but high levels of underweight are also persisting [moderate and severe underweight was highest in India, at 22.7% in girls and 30.7% in boys], but overweight/obesity is also starting to show up there. Our results also find large increases in Latin America, the Caribbean, and in North Africa."

Globally, the prevalence of moderate and severe underweight decreased from 9.2% in 1975 to 8.4% in 2016 in girls and from 14.8% in 1975 to 12.4% in 2016 in boys.

High-Income Countries Plateau as Developing Countries Succumb

Dr Ezzati noted, however, that a flattening off of trends has been seen in northwestern Europe, in the high-income English-speaking, Asia-Pacific regions for both sexes, in southwestern Europe for boys, and in Central and Andean Latin America for girls.

Reflecting on the reasons for this plateauing of BMI in high-income countries among children and adolescents, while adult BMI continues to increase, Dr Ezzati suggested that this might be due to "specific initiatives by governments, community groups, schools, and notable individuals that have increased public awareness about overweight and obesity in children, leading to changes in nutrition and activity that are sufficient to curb the rise in mean BMI."

But he added that the worrying trends in global child and adolescent obesity reflect the impact of food marketing and policies worldwide and the situation whereby healthy nutritious foods are often too expensive for poor families and communities.

"The trend predicts a generation of children and adolescents growing up obese and also malnourished. We need ways to make healthy, nutritious food more available at home and school, especially in poor families and communities, and [implement] regulations and taxes to protect children from unhealthy foods."

The results point to an unhealthy "nutritional transition" in many countries, comprising an increase in nutrient-poor, energy-dense foods that can lead to stunted growth along with weight gain in children, adolescents, and adults, leading to higher BMI and worse health outcomes across the life course.

In particular, the authors point out that the experiences in East Asia, Latin America, and the Caribbean show that the transition from underweight to overweight and obesity can be rapid and overwhelm the national capacity required to engender a healthy transition.

Sophie Hawkesworth, PhD, a public-health nutritionist from the Wellcome Trust in the United Kingdom, which sponsored the study, said: "The double burden relates to poor diets at both ends of the spectrum, so we really want to promote good-quality diets rather than a diet that is nutrient poor and calorie-dense, which results in the consumer lacking enough micronutrients for general and optimal bodily functions."

She added that programs designed to tackle undernutrition need to ensure they are not focused on providing calories alone, which predisposes children to a lifetime risk of obesity. "We need more joined-up thinking and talking about malnutrition across the spectrum."

Fiona Bull, PhD, from the Commission for Ending Childhood Obesity, World Health Organization, cited the example of Ghana.

"Here, there are rising incomes brought in by the discovery of minerals and resources, so Big Food industry enters, and of course local people then start consuming what they perceive as highly desirable, Westernized diets that replace the local diet. These Westernized diets are seen as attractive and tasty — which is what was seen in Northern Europe 25 years ago with birthday parties at McDonald's, for example. Ghana is a most recent example, but 10 years ago these practices started in India and China, where we now see the rising obesity."

Joined-Up Thinking About Malnutrition Needed to Avoid Unhealthy Transitions

Importantly, the Lancet authors note their comprehensive analysis of trends in underweight, as well as overweight and obesity, highlight the disconnect between the global dialogue on overweight/obesity and undernutrition.

Dr Ezzati pointed out that at societal level, "one child could be underweight while another is obese, but they could live next door to each other. Both states are due to not getting enough of the right type of calories."

And prior research has shown that stunted children, ie those who suffer from malnutrition in early life, are also paradoxically more likely to become overweight or obese as they grow older.

"We need to aim for a healthy transition overall," Dr Ezzati stressed. "There are communities that deal with underweight but don't concern themselves with obesity, and there are those communities that tackle obesity but ignore the undernutrition component. The point of this study was to bring these findings to the fore in the same places."

In order to achieve this, it will "require commitment from national and international agencies and donors for replacing the fragmented focus with an integrated approach," he and his colleagues conclude.

Dr Ezzati reports a charitable grant from the AstraZeneca Young Health Programme and personal fees from Prudential, Scor, and Third Bridge outside the submitted work. The coauthors report no relevant financial relationships. Dr Dietz receives consulting fees as a member of the scientific advisory committee for Weight Watchers, as a member and chair of the JPB Foundation's Poverty advisory board, and as a consultant for the Research Triangle Institute: Feeding Infants and Toddlers Study. He has received a grant from Bridgespan to analyze National Health and Nutrition Examination Survey data on early childhood obesity.

Lancet. Published October 11, 2017.  Article, Editorial

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