Worldwide trend towards obesity continues
Only four decades ago, there were twice as many underweight people than obese people in the world. However, this situation has changed dramatically over this relatively short period. Today, there are considerably more people who are obese than people who are underweight. This holds true worldwide, with the exception of Southeast Asia and some parts of Africa. These are findings obtained by an international research consortium using data from over 19 million people. The investigators have now reported their results in an article published in the journal “The Lancet”.
Extreme differences: The highest prevalence of morbid obesity (dark red, BMI >40 kg/m2) is in Polynesia und Micronesia. In Southern Asia, even today 25 % of all adults are undernourished. (purple, BMI < 18,5 kg/m2).
© The Lancet
Severe overweight increases the risk for a whole number of diseases including diabetes, cancer and cardiovascular problems. In its 2013 Global Action Plan, the World Health Organization (WHO) therefore declared it a goal to hold the rise in the prevalence of obesity. On the other hand, a substantial share of the world population still suffers from undernutrition and the associated increased susceptibility to infectious diseases such as tuberculosis as well as health risks for pregnant women and newborns.
In a consortium called “NCD-Risk Factor Collaboration”, researchers teamed up with the goal of identifying global trends in body weight and capturing the current worldwide situation. Led by researchers from Imperial College London, epidemiologists from around the world combined the findings of published studies on body weight and body height from the years 1975-2014 in a meta-analysis. Data from 19.2 million adults from over 200 countries were included in the study.
“The study provides an almost complete picture of the world population’s body weight,” says Hermann Brenner from the German Cancer Research Center (DKFZ) in Heidelberg. Brenner contributed data from Germany to the project. “The long period that we cover in this study and the extremely large case numbers allow us to assess the health relevance of overweight as well as possible prevention measures much more accurately than it has previously been possible.”
Only four decades ago, there were twice as many underweight people than there were obese people in the world. However, this situation has changed dramatically over this short period. Today, there are considerably more people who are obese than people who are underweight. This holds true worldwide, with the exception of South Asia and some parts of Africa.
In the wealthy, developed countries of the world, the rise in body mass index* (BMI) has slowed down since 2000. Around that time, it had become common knowledge that overweight had turned into a serious problem for public health. In many other regions of the world, however, the BMI has continued to rise at an increasing pace since 2000. Globally, this effect predominated. “If this trend continues, then severe overweight, meaning a BMI of more than 35 kg/m², will take the place of underweight as a health risk by the year 2025”, Brenner sums up. The DKFZ researcher stated that, on the whole, the WHO's goal to slow down the rise in BMI has not been accomplished.
The researchers of the NCD-Risk Factor Collaboration emphasize that despite the global trend towards higher body weight, we must not lose sight of the fact that there are large regions in the world where underweight continues to be a major health problem. In these areas – primarily in India and Sub-Saharan Africa – 25% of all adults are still undernourished. Appropriate aid programs urgently need to be continued there.
Age-standardized mean BMI worldwide
Men
1975: 21.7 kg/m2
2014: 24.2 kg/m2
Women
1975: 22.1 kg/m2
2014: 24.4 kg/m2
Decrease in the prevalence of underweight worldwide
Men: from 13.8 percent (1975) to 8.8 percent (2014)
Women: from 14.6 percent (1975) to 9.7 percent (2014)
Increase in the prevalence of obesity worldwide
Men: from 3.2 percent (1975) to 10.8 percent (2014)
Women: from 6.4 percent (1975) to 14.9 percent (2014)
Severe overweight worldwide (>35 kg/m2) in 2014
Men: 2.3 percent
Women: 5 percent
Biggest differences in mean BMI between individual regions in 2014
Men:
Central Africa/South Asia: 21.4 kg/m2
Polynesia/Micronesia: 29.2 kg/m2
Women:
South Asia: 21.8 kg/m2
Polynesia/Micronesia: 32.2 kg/m2
Highest prevalence of underweight in 2014:
South Asia:
Men: 23.4 percent
Women: 24 percent
* Body-Mass-Index, BMI: the weight in kilograms [kg] divided by the square of the height in meters [m2]. For their present study, the researchers defined six BMI categories ranging from <18.5 kg/m2 (underweight) to >40 kg/m2 (morbid obesity).
NCD-Risk Factor Collaboration, M. di Cesare et al.: Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19,2 million participants.
The Lancet, April 2, 2016, DOI: http://dx.doi.org/10.1016/S0140-6736(16)30054-X
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