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Nearly 1 in 3 people worldwide overweight or obese

More than 2 billion children and adults globally were affected by excess weight in 2015, and the percentage of people dying from health conditions stemming from being overweight or obese is rising, according to findings published in The New England Journal of Medicine.

The researchers also noted that among the 20 most populous countries, the highest level of obesity among children and young adults was in the United States, with nearly 13% of its population considered obese.

The findings were released concurrently at the EAT Stockholm Food Forum.

“In recent years, increasing efforts have been made to assess the trends in BMI within and across nations. Other studies have quantified the potential effects of high BMI on a variety of health outcomes,” Ashkan Afshin, MD, MPH, MSc, ScD, assistant professor of global health, Institute for Health Metrics and Evaluation, University of Washington, and colleagues wrote. “These efforts, while useful, did not consider the relationship of high BMI with broader socioeconomic development; they also excluded many data sources, focused exclusively on adults, inadequately captured the skewed distribution of BMI, did not capture emerging evidence on additional outcomes, and did not assess the effect of epidemiologic and demographic transition on disease burden. The BMI that is associated with the lowest risk of death has also been questioned.”

To fill in these information gaps, Afshin and colleagues looked at data from 68.5 million people to evaluate trends in the occurrence of overweightness and obesity in children and adults between 1980 and 2015. They also used the Global Burden of Disease study data and methods to determine the disease burden related to high BMI, based on age, BMI, cause and sex in 195 countries between 1990 and 2015. Analyses of other studies on the effects of excess weight and potential links between high BMI and cancers of the breast, colon and rectum, esophagus, gallbladder and biliary tract, kidney, liver, ovary, pancreas, thyroid and uterus, as well as leukemia, were also conducted. Mixed-effects linear regression models were also used.

Researchers found that in 2015 107.7 million children and 603.7 million adults were obese. In addition, since 1980, the rate of increase in childhood obesity in many countries is greater than that of adults with obesity, the occurrence of obesity has doubled in 70 countries and has increased continuously in most of the other countries studied and high BMI was responsible for 4 million deaths in 2015, and nearly 40% of these deaths were in persons who were not obese.

Afshin and colleagues also wrote that CVD was the leading cause of death and disability-adjusted life-years (DALYs) related to high BMI and accounted for 2.7 million deaths (95% uncertainty interval [UI], 1.8-3.7) and 66.3 million DALYs (95% UI, 45.3-88.5). Worldwide, 41% of BMI-related deaths and 34% of BMI-related DALYs were due to CVD among people with obesity.

In addition, the researchers found that diabetes was the second leading cause of BMI-related deaths in 2015 and contributed to 600,000 deaths (95% UI, 400,00-700,000) and 30.4 million DALYs (95% UI, 21.5-39.9); among all BMI-related deaths that were due to diabetes, 9.5% occurred at a BMI of 30 kg/m² or more and 4.5% occurred at a BMI of less than 30 kg/m².

Chronic kidney disease was the second leading cause of BMI-related DALYs in 2015; 18% of DALYs occurred at a BMI of 30 kg/m² or more and 7.2% at a BMI of less than 30 kg/m². Chronic kidney disease and cancers each accounted for less than 10% of all BMI-related deaths in 2015, and there was a causal relationship between BMI and the cancers studied.

“Over the next 10 years, we will (work) closely with the [U.N.’s Food and Agriculture Organization] in monitoring and evaluating the progress of countries in controlling overweight and obesity,” Afshin said in a press release. “Moreover, we will share data and findings with scientists, policymakers, and other stakeholders seeking evidence-based strategies to address this problem.”

In a related editorial, Edward W. Gregg, PhD, of the CDC, and Jonathan E. Shaw, MD, of the Baker Heart and Diabetes Institute, Melbourne, Australia, wrote of still more holes in obesity-related, chronic disease research and called for action to address them.

“Gaps in available data have forced the [Global Burden of Disease] researchers to make the best of a checkerboard of periodic and suboptimal data to provide a global picture. However, the magnitude of obesity-related morbidity and the demands for effective public health decision-making point to the need for improvements in at least three types of data: efficient, continuous surveillance systems to assess risk factors, prevalence, care and outcomes of chronic diseases; cohorts in more diverse populations to capture variation in progression to outcomes; and platforms for natural experimental studies to determine which of the interventions are working locally and why... [Such] systems would permit policymakers in the hardest hit areas of the world to respond more quickly and to shorten the long learning period that is typically required to overcome such diseases.” – by Janel Miller

Disclosures: Neither Afshin nor Gregg report any relevant financial disclosures. Shaw reports personal fees from Novo Nordisk, outside the submitted work. Please see the study for a list of the other authors’ relevant financial disclosures.