Researchers at the University of Washington in Seattle just released a sobering study about levels of obesity worldwide. Reported in the New England Journal of Medicine, the study shows that obesity is now a global epidemic, affecting 12 percent of adults and 5 percent of children worldwide. Of the 20 most populous countries, the U.S. and China tied for the highest number of overweight adults.
The researchers analyzed data from 1990 to 2015 on 68.5 million people in 195 countries for the Global Burden of Disease study. They found that being overweight or obese accounted for about 4 million deaths in 2015. Forty percent of these were people who were overweight but not obese. (Experts define obesity as a Body Mass Index of 30 or greater. A BMI between 25 and 25.9 indicates that an individual is overweight.) Nearly 70 percent of these deaths were the result of cardiovascular disease — of those, nearly 60 percent occurred in people who were obese. High BMI also contributed substantially to non-fatal disability, particularly from musculoskeletal diseases such as osteoarthritis.
The lowest overall risk of death occurred in people with a BMI of between 20 and 25, the researchers found.
Health Effects of Obesity
Health experts are already aware of the impact of high BMI on overall health. According to Stanford Health Care, obesity is the leading cause of type 2 diabetes, a disease typically seen in adults but which is becoming more prevalent in children as obesity levels rise. Obese persons are also more likely to have atherosclerosis, or hardening of the arteries, and coronary artery disease. Both of these conditions are risk factors for heart attack and stroke. High blood pressure and sleep apnea are also linked to high BMI.
Obesity is also a risk factor for many forms of cancer, according to the Global Burden of Disease report. These include cancer of the esophagus; colon and rectum; liver; gallbladder; pancreas; breast; uterus; ovary; kidney and thyroid as well as leukemia.
Lower Rates of Obesity-Related Disease
Although the GBD study found an overall increase in global rates of obesity, this finding did not correlate with a similar increase in obesity-related disease. The reason for this, the researchers theorize, is that we now have better treatments available for risk factors for cardiovascular disease. Medical interventions to control high blood pressure, high cholesterol and blood glucose, in particular, have proven useful in preventing heart attacks and strokes. Thus, overweight and obese persons are arguably healthier and longer-lived today than they were 25 years ago.
But the lower risk of death from obesity-related illness comes with its own set of problems, experts suggest. In an editorial accompanying the NEJM report, Edward W. Gregg, Ph.D. and Jonathan E. Shaw, M.D. explain:
“Unfortunately, even this success brings a new burden, since the mix of increased prevalence and decreased mortality leads to more years spent with obesity and more time for the damaging coexisting illnesses, such as type 2 diabetes and chronic kidney disease, to develop.”
This is particularly problematic in developing countries such as China, Brazil and Indonesia, where the incidence of obesity in children and young adults has tripled in recent years, Gregg and Shaw write, “An early onset of obesity is likely to translate into a high cumulative incidence of type 2 diabetes, hypertension, and chronic kidney disease.”
Studies in the United States show that type 2 diabetes in children causes more complications than type 1 diabetes. (Type 1 diabetes is also called juvenile diabetes because it is most common in children and young adults.) Thus, it’s likely that the incidence of chronic health conditions will increase as these young people mature.
Good Solutions Are Scarce
Finding solutions to the global increase in obesity rates is uniquely challenging since different factors are probably in play in different parts of the globe. Some suggestions from policymakers in the United States have included limiting the advertisement of unhealthy foods to children, improving school meals and imposing taxes on sugary soft drinks. The latter has already happened in a number of locations, such as some cities in California and in Mexico. However, the impact of these interventions will not be apparent for many years to come.
For now, we can all do our part to combat the obesity epidemic by modeling healthy behaviors for our children and their peers. According to Mayo Clinic, that means exercising for at least 150 to 300 minutes per week, limiting our intake of fat, sugar and alcohol, and eating lots of fruits, vegetables and whole grains.