Obesity Epidemic Is Global, New Study Confirms

Miriam E. Tucker

May 29, 2014

The obesity epidemic extends well beyond the developed world, according to the findings of a new global review. Most startling of all is the fact that no country appears to have made any inroads to tackling this scourge.

Between 1980 and 2013, the combined prevalence of overweight and obesity worldwide rose by 27.5% in adults and 47.1% in children, a new analysis of the Global Burden of Disease Study 2013 shows.

"Obesity has become a major global health challenge. Not only is obesity increasing, but no national success stories have been reported in the past 33 years. Urgent global action and leadership are needed to help countries to more effectively intervene," write Marie Ng, PhD, of the Institute for Health Metrics and Evaluation (IHME), University of Washington, Seattle, and colleagues. They report their findings in an article published online May 28 in the Lancet.

"We were definitely surprised to see that no country had successfully decreased obesity rates in the past 33 years," corresponding author Emmanuela Gakidou, PhD, director of education and training and professor of global health at IHME, told Medscape Medical News. "We expected to find at least a few success stories, as we did with tobacco in a study earlier this year."

In an editorial accompanying the paper, Klim McPherson, PhD, visiting professor of public health epidemiology at New College, Oxford University, United Kingdom, writes that rises in body mass index (BMI) threaten the public-health gains made by reductions in smoking-related illness. For similar success to be made with weight, he says, "An appropriate rebalancing of the primal needs of humans with food availability is essential, which would entail curtailing many aspects of production and marketing for food industries."

Speaking from the European Congress on Obesity in Sofia, Bulgaria, Hermann Toplak, MD, president-elect of the European Association for the Study of Obesity, said, "Overweight and obesity have substantially increased everywhere in the world and have undoubtedly become the major health issues of the 21st century.

"Over the past decades the modernization of our world, with all the technology around us, has led to physical inactivity on all levels. It is well-known that people who stop exercising lose the control of their food intake, whereas those who continue exercising eat adequately in relation to their energy needs," added Prof. Toplak, of the department of medicine, University of Graz, Austria.

Obesity Around the World

The investigators examined several data sources for 188 countries in 21 regions, including survey programs that reported weight and height, several large databases including those maintained by the World Health Organization, and information obtained from national health ministry websites. They also reviewed articles from the literature published between 1980 and 2012, comprising 1769 country-years of data for 183 countries.

The authors used the standard definitions for overweight (BMI 25 – 30 kg/m2) and obesity (BMI greater than 30 kg/m2).

In addition, they used a variety of statistical techniques to account for self-reported underreporting of weight by women and self-reported overreporting of height for men, as well as for both missing and overlapping data.

In all, the number of overweight and obese people worldwide increased from 857 million in 1980 to 2.1 billion in 2013. Among men, the proportion overweight increased from 28.8% in 1980 to 36.9% in 2013. For women, the proportion rose from 29.8% to 38.0% during the same period. Men were more likely than women to be overweight or obese in developed countries, whereas the reverse was true for developing countries.

The greatest increase in overweight and obesity occurred during 1992–2002 and has slowed down since, particularly in developed countries. "Rates in developed countries may not be rising as quickly as they have been in the past, but it is troublesome to see substantial increases in developing countries," Dr. Gakidou told Medscape Medical News.

The prevalence of overweight or obesity has also been rising among children and adolescents in both the developed and developing world since 1980. In developed countries, the proportions were 23.8% of boys and 22.6% of girls in 2013 compared with 16.9% and 16.2%, respectively, in 1980. In developing countries, 12.9% of boys and 13.4% of girls were overweight or obese in 2013, up from 8.1% and 8.4%, respectively, in 1980.

Of the 671 million obese individuals in the world, more than 50% live in 10 countries: the United States, China, India, Russia, Brazil, Mexico, Egypt, Germany, Pakistan, and Indonesia. In 2013, the United States accounted for the highest proportion of obese people, 13% of the world's total. China and India together accounted for 15%. Although age-standardized obesity rates were lower in developing vs developed countries, 62% of the world's obese people live in developing countries, the authors note.

In addition, the investigators found that having a high prevalence of obesity in 1980 did not mean that a region would have a slower increase in rates of overweight and obesity later in the study. The largest increases in obesity since 1980 for both men and women have occurred in Saudi Arabia and Bahrain. The United States was among the top 15 countries for increases in obesity for both sexes, along with Australia and the United Kingdom.

What Can Be Done?

The authors note that most deaths attributable to overweight and obesity are cardiovascular deaths. Yet data suggest that only 31% of the coronary heart disease risk and 8% of the stroke mortality associated with obesity are mediated through high blood pressure and cholesterol and therefore the impact of drug therapy may be limited.

Dr. Gakidou told Medscape Medical News, "Treating those conditions can only go so far in reducing the health risks associated with being overweight or obese. Also, dietary, economic, cultural, and lifestyle factors are so widely varied across countries that it is difficult to pinpoint mortality increases on a singular cause. While obesity may be a global issue, the challenges all begin at local levels….Health improvements must be made holistically to offset risks for other chronic conditions that may arise, such as kidney disease, cancer, or diabetes."

There is no universal cure-all, she said. "Changes must be multilateral to meet the complexity of cultural traditions and dietary norms of the world's many ethnic groups. We need to continue to monitor levels and rates of obesity and tailor public-health solutions toward specific groups. By working with local communities, we can better create strategies that address both physical activity and diet in order to reduce obesity prevalence."

Policy changes are needed, Dr. McPherson said. "The solution has to be mainly political, and the question remains, as with climate change, where the international will is to act decisively in a way that might restrict economic growth in a competitive world, for the public's health. Nowhere yet, but voluntary salt reduction might be setting a more achievable trend. Politicians can no longer hide behind ignorance or confusion."

This study was funded by the Bill and Melinda Gates Foundation. Dr. Ng and Dr. Gakidou have reported no relevant financial relationships. Disclosures for the coauthors are listed in the article. Dr. McPherson has reported no relevant financial relationships.

Lancet. Published online May 28, 2014. Abstract, Editorial


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