Dr. Peter Katzmarzyk of Pennington Biomedical was among hundreds of researchers who tracked BMI measurements collected in more than 3,600 population-based studies since 1990. Published in The Lancet .
Underweight and obesity are associated with adverse health outcomes across the lifespan. We estimated the individual and combined prevalence of underweight/thinness and obesity, and their changes, from 1990 to 2022 for adults and school-age children and adolescents in 200 countries and territories.
Methods
We used data from 3,663 population studies involving 222 million participants measuring height and weight in samples representative of the general population. We used a hierarchical Bayesian model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥ 20 years) and school-age children and adolescents (5 to 19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI < 18.5 kg/m 2 ) and obesity (BMI ≥ 30 kg/m 2 ). For school-aged children and adolescents, we report thinness (BMI < 2 SD below the WHO growth reference median) and obesity (BMI > 2 SD above the median) .
Results
From 1990 to 2022, the combined prevalence of underweight and obesity among adults decreased in 11 countries (6%) for women and 17 (9%) for men, with a posteriori probability of at least 0.80 that the observed changes are true decreases.
Overall prevalence increased in 162 countries (81%) for women and in 140 countries (70%) for men with a posterior probability of at least 0.80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean, Polynesia and Micronesia, as well as countries in the Middle East and North Africa.
The prevalence of obesity was higher than that of underweight, with a posterior probability of at least 0.80 in 177 countries (89%) for women and 145 (73%) for men in 2022, while the opposite was true. true in 16 countries (8%) for women and 39 (20%) for men.
From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0.80, and increased among girls in 140 countries (70 countries). %) and children in 137 countries (69%) with a posterior probability of at least 0.80.
The countries with the highest combined prevalence of thinness and obesity among school-aged children and adolescents in 2022 were Polynesia, Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. The combined prevalence was also high in some South Asian countries, such as India and Pakistan, where thinness remained prevalent although it had declined.
In 2022, obesity among school-aged children and adolescents was more prevalent than thinness, with a posterior probability of at least 0.80 among girls in 133 countries (67%) and boys in 125 countries (63%), while the opposite occurred. in 35 countries (18%) and 42 countries (21%), respectively.
In almost all countries, both for adults and for school-age children and adolescents, the increase in double burden was due to the increase in obesity, and the decrease in double burden was due to the decrease in underweight or thinness.
The combined burden of underweight and obesity has increased in most countries, driven by rising obesity , while underweight and thinness remain prevalent in South Asia and some regions of Africa. A healthy nutrition transition that improves access to nutritious foods is needed to address the remaining burden of underweight while slowing and reversing the rise in obesity.
Obesity is now the most common form of malnutrition in most countries, and rates have increased in all categories of men, women, children and adolescents since 1990. Rates of obesity Obesity among adult men has almost tripled since 1990, and obesity rates among women have doubled during this same period. time. Obesity rates among children and adolescents have also quadrupled during this period. In 2022, nearly 880 million adults and nearly 160 million children were living with obesity.
The prevalence of malnutrition worldwide was shared by the NCD Risk Factor Collaboration, a network of health scientists from around the world who provide and evaluate data on major risk factors for all countries, in collaboration with the World Health Organization. Dr. Peter Katzmarzyk, associate executive director of the Department of Population and Public Health Sciences at the Pennington Biomedical Research Center in Baton Rouge, was a contributing author to this publication.
Network participants reviewed body mass index data from more than 3,600 studies conducted between 1990 and 2022, determining rates of malnutrition, whether due to obesity or underweight, for all countries, as well as the degree of evolution of the data. over the years.
"Current obesity rates seem overwhelming, but the trend has been in this direction for more than three decades," said Dr. Katzmarzyk. “With more than a billion people living with obesity, it is important that we do not talk about obesity in isolation. We know that obesity can directly lead to comorbidities, such as high blood pressure, heart disease, diabetes, cancer, and obstructive sleep apnea. By better understanding the root causes of obesity, we can identify ways to prevent, treat, or even reverse its adverse effects.
Of the more than 190 countries represented in this study, the United States ranks 10th in the world for the prevalence of obesity among men, with the percentage of men increasing from 16.9 percent in 1990 to 41.6 percent. cents in 2022.
Among women, the obesity rate in 1990 was 21.2 percent, rising to 43.8 percent in 2022, ranking 36th in the world.
Among children, the obesity rate increased from 11.5 percent in 1990 to 21.7 percent in 2022, placing the United States 26th in the world. The obesity rate among girls in the United States ranks 22nd in the world, with the rate increasing from 11.6 percent in 1990 to 19.4 percent in 2022.
The findings echo the prevalence of obesity at granular levels, as in 2020, 38% of Louisiana adults face obesity, according to county health rankings and roadmaps.
“The results of this study strongly support the value of Pennington Biomedical’s mission,” said Dr. John Kirwan, CEO of Pennington Biomedical. “As the prevalence of obesity increases over the decades, we remain steadfast in our commitment to promoting metabolic health, eliminating metabolic diseases, uncovering the triggers of obesity, and improving the health of all. “I express my gratitude and welcome Dr. Katzmarzyk’s contribution to this important global study.”
During the same period, underweight rates among children, adolescents and adults fell globally, and underweight rates among men fell sharply in some African countries. Both obesity and underweight are forms of malnutrition, with obesity rates higher than underweight rates among boys and girls in two-thirds of the world´s countries.
The Pennington Biomedical International Childhood Obesity, Lifestyle and Environment Study is one of thousands of studies that have reported these findings. More than 6,000 children from all inhabited continents participated in the study.
Discussion
Our results show three major global transitions in underweight and obesity since 1990.
- First, the combined prevalence of these forms of malnutrition has increased in most countries, with the notable exceptions of countries in South and Southeast Asia and, for some age and gender groups, Africa. sub-Saharan.
- Second, the decrease in double burden was largely due to declines in the prevalence of underweight, while the increases were due to increases in obesity , leading to a transition in the prevalence of underweight. underweight to the prevalence of obesity in many countries. The increase in dual burden has been greatest in some low- and middle-income countries, particularly those in Polynesia and Micronesia, the Caribbean, and the Middle East and North Africa; new high-income countries like Chile; and, for men, in Central Europe. These countries now have a higher prevalence of obesity than high-income industrialized countries.
- Finally, the transition to obesity was already evident among adults by 1990 in much of the world, as evidenced by the large number of countries in which adult obesity exceeded underweight at that time, and continued since then. children and adolescents of school age.
