A consortium of health scientists around the world, the NCD Risk Factor Collaboration, conducted a massive-scale analysis of global trends of mean body mass index (BMI) in 200 countries and found that if post-2000 trends continue, the probability of reaching the World Health Organization’s goal regarding global obesity is close to zero.
Estimates indicate that by 2025, the prevalence of global obesity will reach 18 percent in men and surpass 21 percent in women, while the number of people who are malnourished or underweight still remains a problem in the world’s poorest regions, especially South Asia.
The research article, “Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1,698 population-based measurement studies with 19·2 million participants,” was published in the journal The Lancet.
A high BMI is an important risk factor for a number of serious conditions, such as cardiovascular and kidney diseases, diabetes, and certain cancers. Due to the increasing prevalence of such diseases over the last decades and their consequences on population health and economic burden, WHO devised a global plan to halt by 2025 the rise in the prevalence of obesity.
The research team pooled population-based data to estimate trends from 1975 to 2014 in mean BMI in order to estimate the prevalence of categories ranging from underweight to morbid obesity. The scientists also estimated the probability of achieving WHO’s global obesity target. The report included data from 19.2 million men and women age 18 years or older, from 186 countries covering 99 percent of the world’s population.
Results showed that since 1975, the proportion of obese men has more than tripled (from 3.2 percent to 10.8 percent), and the proportion of obese women has more than doubled (6.4 percent to 14.9 percent). But the proportion of underweight people has seen an opposite trend, from 13.8 percent to 8.8 percent in men and from 14.6 percent to 9.7 percent in women.
Also, global age-corrected BMI has increased from 21.7 kg/m2 in 1975 to 24.2 kg/m2 in 2014 in men, and from 22.1 kg/m2 in 1975 to 24.4 kg/m2 in 2014 in women.
If the rate of obesity continues like this to 2025, 18 percent of men and 21 percent of women will be obese, and more than 6 percent of men and 9 percent of women will be severely obese. Researchers also found that rates of obesity surpassed rates of underweight women in 2004 and in men in 2011.
“Over the past 40 years, we have changed from a world in which underweight prevalence was more than double that of obesity, to one in which more people are obese than underweight,” said the study’s senior author, Prof. Majid Ezzati from the School of Public Health at Imperial College London, in a news release. “If present trends continue, not only will the world not meet the obesity target of halting the rise in the prevalence of obesity at its 2010 level by 2025, but more women will be severely obese than underweight by 2025.”
However, researchers emphasize that under-nutrition and excessively low body weight remains an important public health issue, and the growing obesity rates should not divert attention from the world’s poorest regions.
“A focus on obesity at the expense of recognition of the substantial remaining burden of under-nutrition threatens to divert resources away from disorders that affect the poor to those that are more likely to affect the wealthier in low-income countries,” said Prof. George Davey Smith from the MRC Integrative Epidemiology Unit, School of Social and Community Medicine.
In South Asia, nearly a quarter of the population is still underweight, and in Central and East Africa, the number of underweight people remain higher than 12 percent in women and 15 percent in men.