It is well established that people with both Type-1 and Type-2 diabetes have an increased risk of developing depression, but the causes remain poorly understood.
The research showed that higher levels of galectin-3 an inflammatory protein is the culprit.
Galectin-3 is a key protein involved in promoting inflammatory immune system responses that are needed to repair tissue damage throughout the body, in response to injury or disease.
According to the researchers, galectin-3 also linked with Alzheimer's and cardiovascular diseases, maybe useful for diagnosis of depression or maybe a new target for treating depression associated with Type-1 diabetes, which could lead to better patient care.
"We found that people with Type-1 diabetes and depression had higher galectin-3 levels, yet no other diabetes-related metabolic changes could account for these elevated levels," said Eva Olga Melin from Lund University, Sweden.
The study, published in the journal Endocrine Connections, analysed data on measurements of galectin-3 levels in 283 people, aged between 18-59 years, with Type-1 diabetes for a year.
The results showed that both men and women with Type-1 diabetes and depression also had significantly higher galectin-3 levels.
"...these findings suggest that further investigating the role of galectin-3 could lead to improved diagnosis and maybe better treatment outcomes for patients in the future," Melin said.