A new study found that a child is almost twice as likely to develop type 1 diabetes if the father has the condition. The study was published in the journal Diabetologia. This was the largest of its kind study and suggests that exposure to type 1 diabetes in the womb confers long-term protection against the condition in children with affected mothers relative to those with affected fathers.

Type 1 diabetes is an autoimmune disease. In this condition, your immune system attacks and destroys insulin-producing cells in your pancreas. While it is usually diagnosed in children and young adults, it can develop at any age.

The researchers said that understanding what is responsible for the protection could help in developing new treatments to prevent type 1 diabetes. Dr Lowri Allen from Cardiff University in the UK and the lead researcher of the study said, “Individuals with a family history of type 1 diabetes are 8-15 times more likely to develop the autoimmune condition – however, studies have shown the risk is higher if the affected relative is the father rather than the mother. We wanted to understand this more.”

Previous studies have suggested that maternal type 1 diabetes is associated with relative protection against type 1 diabetes in offspring during early life.

For the study, the researchers took into consideration 11,475 individuals who were diagnosed when they were between 0 and 88 years old. The results show they were almost twice as likely (1.8 times more likely) to have a father with type 1 diabetes as a mother with the condition.

Dr Allen said, “Taken together, our findings suggest the relative protection associated with having a mother versus father with type 1 diabetes is a long-term effect that extends into adult life.”

However, the timing of the parent’s diagnosis was important. An individual was only more likely to have a father, rather than a mother, with type 1 diabetes, if the parent was diagnosed before the individual was born.

In other words, having a mother with type 1 diabetes only appears to provide a child with protection against the condition (relative to having a father with type 1 diabetes) if the mother has the condition during pregnancy, the findings showed. Further research is needed to determine what it is about exposure to type 1 diabetes in the womb that is most important.

The researchers asked, “Is it exposure to high blood glucose levels, insulin treatment, antibodies associated with type 1 diabetes, a combination of these, or exposure to another aspect of type 1 diabetes?”