Siblings of children with type 1 diabetes face more than 10 times the risk of developing the disease, first large-scale Korean analysis finds

A first-of-its-kind, large-scale Korean study found that siblings of children and adolescents with type 1 diabetes face more than 10 times the risk of developing the disease compared with the general pediatric population.

The Korea Disease Control and Prevention Agency’s National Institute of Health announced the results of a multicenter collaborative study on the familial occurrence and clinical characteristics of type 1 diabetes in children and adolescents on the 13th.

The study was supported by the National Institute of Health and led by Seoul National University Bundang Hospital. It examined 936 patients aged 18 years or younger who were diagnosed at 18 university hospitals in Korea from 2010 to 2024 to determine the rate of disease among relatives according to family history.

The study found that 32 patients, or 3.4% of the total, had a family history of type 1 diabetes in a parent or sibling. Parents were affected in 1.1% of cases.

In particular, an analysis of 779 siblings of patients found that 23 (3.0%) developed type 1 diabetes. This rate is more than 10 times the 0.26% incidence in the general pediatric population in Korea.

Among twins, both developed the disease in three of seven pairs, for a concordance rate of 42.9%. The researchers said this indicates a very strong influence of genetic factors.

In addition, patients diagnosed second within a family had lower blood glucose and glycated hemoglobin levels at diagnosis than the first patient, and a significantly lower rate of diabetic ketoacidosis, an acute complication.

The researchers said that greater awareness of the disease because another family member had been diagnosed first may have contributed to earlier detection in subsequent patients.

Jae Hyun Kim, a professor in the Department of Pediatrics at Seoul National University Bundang Hospital, said, "This study has significant public health value because it identified the incidence patterns associated with family history among children and adolescents with type 1 diabetes in Korea and quantified the specific risk for their siblings." He added, "It suggests that a new paradigm shift may be possible in which type 1 diabetes can be prevented before pancreatic dysfunction develops."

Won Ho Kim, director of the Division of Chronic Disease Convergence Research at the National Institute of Health, said, "This is the first Korean study to identify siblings as a high-risk group." He added, "We will establish a national registry for diabetes in children and adolescents and continue research to generate scientific evidence."

Type 1 diabetes is an autoimmune disease in which the immune system attacks the pancreatic beta cells that produce insulin, resulting in little to no insulin production. It primarily develops during childhood and adolescence, and ongoing insulin treatment is needed after diagnosis.

The study results were published in the international journal Diabetes & Metabolism Journal.