Eight out of 10 diabetes patients in their 30s and 40s in Korea are also obese, according to a new study. The findings suggest that "obese-type diabetes" is rapidly spreading among younger age groups, breaking from the traditional pattern of "lean diabetes," which was caused by reduced insulin secretion and long considered typical of Korean diabetes.
Kangbuk Samsung Hospital announced on the 25th that a research team led by Professor Park Se-eun of the Department of Endocrinology analyzed the obesity status of adult diabetes patients in Korea based on the recently released "Diabetes Fact Sheet 2025."
According to the analysis, 52.4% of adult diabetes patients in Korea had a body mass index (BMI) — calculated by dividing weight (kg) by the square of height (m) — of 25 kg/m² or higher. The obesity rate was particularly high in younger age groups. Among diabetes patients in their 30s and 40s, the prevalence of obesity reached 81.3% and 76.7% respectively, confirming that most young diabetes patients also struggle with obesity. In contrast, the obesity prevalence among elderly diabetes patients aged 65 and over was 38.3%, more than a twofold gap. The findings suggest that obesity is a decisive cause of diabetes among younger generations.
Abdominal obesity rates, measured by waist circumference, showed a similar pattern. Among all adult diabetes patients, 61.1% had abdominal obesity, with the prevalence reaching 78.4% among those in their 30s and 73.1% among those in their 40s. Abdominal obesity is considered a major factor that increases insulin resistance, making blood sugar control difficult, and also raises the risk of cardiovascular diseases such as myocardial infarction and stroke. The research team analyzed that the rising obesity rate driven by Westernized diets and lack of exercise is fueling the increase in "obese-type diabetes," dramatically changing the landscape of diabetes in Korea.
"When obese-type diabetes begins at a young age, the period of exposure to complications becomes longer, which can make it even more fatal," Professor Park said. "Treatment should not stop at simply lowering blood sugar levels. Integrated treatment that combines weight loss and lifestyle improvement is necessary."
The research findings were published in the March 2026 issue of the Diabetes & Metabolism Journal, the official academic journal of the Korean Diabetes Association.
