Excess weight is at the top of the global health problems that plague the world. Obesity has already become the most common form of malnutrition in most countries and its incidence is growing unstoppably throughout the globe. A scientific review from Sichuan University (China) published this Monday in the journal Jama Pediatrics emphasizes the impact of this phenomenon on the child and youth population and, in line with other previous research, confirms the upward trend: the number of cases registered between 2012 and 2023 is 60% higher than that reported in the first decade of this century. According to research, currently, one in five children on the planet is overweight (overweight or obese).
The authors have identified great heterogeneity in prevalence between countries and also diverse risk factors, from dietary to behavioral. For example, skipping breakfast, excessive exposure to screens, or smoking during pregnancy increase the likelihood of developing obesity in childhood. Scientists also warn that excessive fat accumulation in the first years of life can be perpetuated into adulthood and is the gateway to other diseases, such as depression and hypertension.
This is not the first time that attempts have been made to put figures and perspective on this phenomenon. Seven years ago, research estimated that, in 2015, there were 107.7 million children (5% of the child population) and 603.7 million adults with obesity. The trend, even then, was pointing upwards and time continues to confirm it. According to estimates by the World Obesity Federation, by 2025 there will be 310 million people aged five to 19 with this disease; and in 2030 there will be 350 million. The new research published in Jama Pediatrics It moves in the same direction and delves deeper into the risk patterns and dangers that lurk around this disease.
Scientists at Sichuan University reviewed more than 2,000 studies from 154 countries involving nearly 46 million people. The research concluded that the global prevalence of obesity in children and adolescents is 8.5%, although there is great variability between regions. For example, in Vanuatu, an island in Oceania, the prevalence is 0.4% and in Puerto Rico, 28.4%. In Spain it is 9.28%.
To begin with, high-income countries have higher rates of obesity and overweight, but large differences were also identified among them: in the United States, the prevalence is 18.6% and in Japan, also a developed territory, it is close to 4%. . “Differences in eating habits may influence this disparity. European countries and the United States often prefer a diet of processed foods. In contrast, Southeast Asian countries have historically prioritized diets rich in whole grains and vegetables, which are generally considered healthier options,” the researchers reason in the article.
Unfortunately, we are not knowing how to stop this obesity pandemic.”
Albert Goday, head of the Endocrinology section at Hospital del Mar
Manuel Tena, group leader of the Networked Biomedical Research Center (CIBER) of Obesity and Nutrition, points out that the strength of this research, in which he has not participated, is “the power in the integration of data”, although it also presents some limitations (which the authors themselves recognize), such as the lack of information in some countries or the different criteria between studies to identify obesity and overweight. “Certain interpretations must be taken with caution,” he reflects.
As this is a scientific review, Tena points out, the findings are not new, but they “confirm the trend” found in smaller studies. Among them, obesity is no longer just a thing in rich countries, but is expanding throughout the globe: in Ecuador, for example, the prevalence is 12%, in Mexico it is 16.5% and in Kuwait exceeds 20%.
For Tena, “the most worrying thing” is that, far from this increase in cases stopping, the trend in children and adolescents continues to rise. The study analyzed the prevalence in two periods (between 2000 and 2011; and from 2012 to 2023) and concluded that, if in the first decade of the century, the prevalence of obesity was 7%, in the last 10 years it reached 11. 3%. “In some parts of the world, there are studies in adults where it is seen that trends are stabilizing. But in childhood obesity, the trend is growing and that means we are going in the wrong direction,” laments Tena.
Albert Goday, head of the Endocrinology section at the Hospital del Mar in Barcelona, who has not participated in this research either, expresses himself along the same lines: “Unfortunately, we are not knowing how to stop this pandemic. We were able to stop Covid or HIV, but obesity, which comes from further away, we were not able to stop and has great consequences for health.” The results of this study are, in his opinion, “a cause for calm concern”: “It is a prediction of what awaits us in the future. It is a prediction that the obesity pandemic is not going to be better than what we have now. The possibility that an obese child will be an obese adult is high.”
Maternal obesity and smoking during pregnancy
This new research also breaks down the risk factors that play a role in the development of overweight and obesity in childhood. To begin with, the prevalence is higher in boys than in girls. And maternal obesity and smoking during pregnancy also increase the risk of childhood and adolescent obesity. Maternal diabetes or gestational weight gain, on the other hand, showed an impact, but a more “modest” one, the authors point out. Regarding the influence of paternal obesity, which other studies considered a risk factor, this study revealed “the opposite,” say the signatories.
The study also directly points to the influence of environmental factors and specific behavioral and dietary patterns. Skipping breakfast, for example, was associated with a higher risk of pediatric obesity. And “surprisingly,” they added, eating more than three meals a day was linked to a lower risk. “Which could be explained by the theory that eating several small meals throughout the day is healthier than three large meals,” the authors reflect.
Like a whiting chasing its tail, Chinese scientists also emphasize the vicious cycle around physical exercise or lack thereof: children with obesity practice less physical activity, which increases their levels of sedentary lifestyle, a behavior that, in turn, contributes to the development of obesity. “Our findings also showed that children who exercised regularly had a much lower chance of obesity. Furthermore, we observed that playing on the computer for more than two hours a day was associated with an increased risk of excess weight, and time spent watching television also showed a positive correlation, although not significant,” they explain in the study. . The authors maintain that exposure to screens also increases the risk of obesity “through greater exposure to food marketing, increased mindless eating while watching screens, displacement of time spent on physical activities, reinforcement of sedentary behaviors, and reduction in sleep duration.”
Tena also emphasizes another key factor revealed by the scientific review: hours of sleep. “Having good sleep habits, such as sleeping 10 or more hours, reduces the risk,” he notes.
The master key to other diseases
Obesity is, apart from a health problem in itself, the key that opens the door to a world of chronic diseases in the medium and long term. Children who are overweight are more likely to develop prediabetes, asthma, hypertension or fatty liver. The latter, if uncontrolled and persists over time, can lead to cirrhosis or liver cancer. “Our research revealed a high prevalence of comorbidities in children and adolescents with obesity. The highest pooled prevalence was found in depression, which approximately one in three children with obesity may experience, followed by hypertension, with a pooled prevalence of 28%,” conclude the authors, who call for, in the treatment of obesity, these other associated diseases are evaluated and treated simultaneously to prevent the progression of both.
Goday describes a growing phenomenon associated with this increase in obesity at such early ages: “We see adult diseases in children. The possibility that an obese child will also be obese as an adult is high. It perpetuates itself and has more consequences for health: chronic diseases appear sooner where the exposure time matters and implies more damage to the body.” It’s not just the weight itself, but all the health problems that come with it, he emphasizes. And he calls for reinforcing healthy lifestyle habits, such as physical exercise, traditional games away from screens, eating breakfast every day or eating as a family instead of alone and watching television or cell phones.
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