HN Summary

• Parental diabetes linked to childhood type 1 diabetes:  New research shows that children whose mothers had gestational diabetes or fathers had type 2 diabetes face significantly higher risks of developing type 1 diabetes compared to children of parents without diabetes.

• Possible biological and lifestyle mechanisms: The study suggests that insulin resistance, shared family behaviors, and epigenetic changes from high blood sugar in parents may increase a child’s susceptibility to type 1 diabetes.

• Clinical implications:  Including maternal gestational diabetes and paternal type 2 diabetes in family history assessments could help healthcare providers identify at-risk children earlier, enabling timely monitoring, diagnosis, and prevention of serious complications.

Research from The Institute shows strong evidence that gestational and paternal type 2 diabetes in parents, besides type 1, can signal higher risks for type 1 diabetes in kids.

A recent systematic review and meta-analysisconducted by researchers from the Research Institute of the McGill University Health Centre (The Institute) and published in EClinicalMedicine reveals that children of mothers with gestational diabetes or fathers with type 2 diabetes have higher chances of developing type 1 diabetes than kids whose parents do not have any type of diabetes. The study provides insights that could help doctors identify at-risk children earlier.

“In Canada, a quarter of children with type 1 diabetes are diagnosed late, often presenting with diabetic ketoacidosis—a life-threatening but preventable condition,” says senior author Dr. Kaberi Dasgupta, Senior Scientist in the Metabolic Disorders and Complications Program at The Institute. “Since population-wide or genetic screening for early detection hasn’t yet proven cost-effective, it’s crucial that we identify clear, accessible risk factors to accelerate type 1 diabetes detection.”

Specifically, the study found that children whose mothers had gestational diabetes during pregnancy were 94 per cent more likely to develop type 1 diabetes compared to children of mothers without diabetes. Similarly, having a father with type 2 diabetes was linked to a 77 per cent higher risk. The study also suggests a possible link between maternal type 2 diabetes and type 1 diabetes in children, although more data are needed to confirm whether the risk is real.

Implications for families and clinicians

Diabetes is a condition where blood sugar (glucose) levels are too high. In type 1 diabetes, the immune system damages the insulin-producing cells in the pancreas—the hormone that helps move blood sugar into cells to provide energy—leaving the body without enough insulin to regulate blood sugar. In gestational diabetes and type 2 diabetes, the body does not respond properly to insulin, a condition often linked to excess weight, low physical activity and genetic factors.

“What is interesting is that type 1 diabetes is a disease of lack of the hormone insulin while gestational diabetes and type 2 diabetes stem mostly from the body’s resistance to the hormone. What may be happening is that genes, environments and behaviours that create insulin resistance may also, in some cases, trigger the immune reactions that lead to type 1 diabetes,” adds Dr. Dasgupta.

Integrating these parental health indicators into clinical care could help healthcare providers remain vigilant when evaluating children with symptoms such as excessive thirst or urination, allowing for earlier diagnosis of type 1 diabetes and the prevention of serious complications.

Intriguing connections between type 1, type 2 and gestational diabetes

“The connections we found between different types of diabetes are intriguing, given that each has distinct biological causes. They support a growing view that behaviours leading to excess weight and insulin resistance—typically linked to type 2 diabetes—may also increase the risk of type 1 diabetes in people whose immune systems are prone to attacking insulin-producing cells,” says Dr. Dasgupta.

A 2019 meta-analysis by researchers at Soochow University in China found that gestational diabetes was linked to a 66 per cent higher risk of type 1 diabetes in children. This new study, which includes more than twice as many studies, offers a robust synthesis of current evidence and shows the risk is even greater than previously estimated. It is also the first meta-analysis to examine the link between paternal type 2 diabetes and type 1 diabetes in offspring.

The authors of the study suggest several possible explanations for their findings. Broadly, the economic, dietary and lifestyle factors that contribute to parental obesity and gestational diabetes may also increase the likelihood of obesity in children—an established risk factor for type 2 diabetes but now also recognized as a risk factor for type 1 diabetes.

“Several mechanisms may be at play. Families often share lifestyle and eating habits, which can raise the likelihood that children will be affected. But beyond that, high blood sugar levels may also cause biological changes in parents that could increase their children’s risk of developing type 1 diabetes,” explains Laura Rendon, co-first author of the study, who completed an MSc in experimental medicine at The Institute and, as someone living with type 1 diabetes herself, finds deep personal meaning in conducting this research.

For instance, the authors suggest that high blood sugar during pregnancy may stress the fetus’s insulin-producing beta cells, reducing their number at birth or making them more vulnerable to damage later in life. It may also trigger epigenetic changes—modifications to proteins and molecules attached to DNA—that increase the risk. Likewise, high blood sugar in fathers with type 2 diabetes may cause epigenetic changes in their sperm, potentially influencing their child’s risk of developing type 1 diabetes.