June 26 (UPI) -- The number of people diagnosed with thyroid cancer has more than doubled worldwide since 1990, an analysis published Friday by JAMA Network has found.
Much of the increase has been fueled by a rapid rise of cases in countries in southern and eastern Asia, which accounted for more than 40 percent of global diagnoses in 2017, the most recent year for which data are available, the researchers said.
In addition, more than 70 percent of those diagnosed with the cancer are women, they said.
"The significant geographical disparities might be explained by health resource imbalance and gene-environment interactions," co-author Zhijun Dai told UPI.
"A third of thyroid cancer patients existed in countries with high socio-demographic index," a comprehensive measurement of educational level, per capita income and fertility rate, said Dai, a professor of breast surgery at Zhejiang University School of Medicine in Hangzhou, China,.
In the United States, more than 50,000 people have been diagnosed with thyroid cancer, making it the 11th most common cancer overall, according to the National Cancer Institute. However, it is the fifth most common cancer in women.
Dai and colleagues derived their estimates for worldwide rates of the disease using data from the Global Health Data Exchange and the Global Burden of Disease Study.
There were 255,490 incident cases of thyroid cancer in 2017, up from 95,030 in 1990, a 169 percent increase, they found. Deaths from the disease nearly doubled over the same period to 41,240 from 22,070, an 87 percent increase, the researchers said.
China, the United States and India have the most cases of the disease worldwide, collectively accounting for more than one-third of all diagnoses, they said.
The United States had roughly 10 percent of all new cases diagnosed in 2017, they found.
"Large [differences] exist in thyroid cancer epidemiological patterns across gender, age and country, which provides data support for governments to improve national and local cancer control policies," Dai said.