China has the world’s biggest diabetes epidemic, and it continues to get worse, according to the latest study of the disease’s devastating effects on the world’s most populous country, which has risen from poverty to become an economic superpower in 30 years.

Previous studies had found rapidly rising rates of the disease, and the newest, published last week by The Journal of the American Medical Association, shows that China has just passed the United States: 11.6 percent of Chinese adults have the disease, compared with 11.3 percent here; in 1980, prevalence was below 1 percent.

The total — 114 million people — means China has about a third of the world’s diabetes sufferers, who are at greater risk of heart disease, stroke and kidney failure. That will put enormous strain on the country’s public health system, the authors said.

Perhaps even more alarming, the study, which involved testing almost 99,000 people, found that half had “prediabetic” blood glucose levels.