NEW YORK — Obesity now affects 1 in 10 people in the world, it is rising in countries rich and poor, and in many countries it is increasing faster in children than adults, according to a new study.

The researchers estimated more than 107 million children and 603 million adults are obese.

The study was led by a team at the University of Washington in Seattle. It was published online by the New England Journal of Medicine and presented at a food science and policy meeting in Stockholm.

Researchers reported on 195 countries, although data was incomplete or nonexistent for many of them. They made assumptions and used mathematical modeling to fill in gaps.

Some of the findings:

Obesity rates doubled in 73 countries between 1980 and 2015. Countries where obesity did not increase significantly included Afghanistan, Bulgaria, and the Democratic Republic of the Congo.

Worldwide, about 5 percent of children and 12 percent of adults were obese in 2015. In the U.S. about 17 percent of children and 38 percent of adults are obese, according to earlier CDC estimates.

Among the 20 largest countries, the United States had the highest level of obesity among children and young adults. Bangladesh had the lowest.

Egypt had the highest rate of obese adults. Vietnam had the lowest.

The United States had the largest number of obese adults in 2015, with 79 million.