Norwegian researchers found children had higher blood glucose levels if their parents showed a heightened fear of their child having a hypoglycaemic episode.
The fear was also associated with higher incidence of hypoglycaemic episodes in the past year.
Researchers based at Bergen University College, Norway, followed 200 parents of 115 children with type-1 diabetes aged 1-15 years old.
Mothers were found to showed higher fear levels than fathers. Parents were also more likely to fear hypoglycaemia if their child had an additional disease or mental disorder.
The study also showed that parents were more likely to use inappropriate behaviour to avoid hypoglycaemia if their child used injections to control their diabetes rather than an insulin pump.
The researchers said the study could not identify cause and effect. However, they suggested that experiences with problematic hypoglycaemic episodes worry parents and subsequently lead to more restrictive insulin doses and poorer diabetes control in the child.
Diabetes UK called for better psychological support for parents and their children with diabetes.
Dr Iain Frame, director of research at Diabetes UK, said: ‘Having a child diagnosed with diabetes has major implications for a family. It can be a worrying time and therefore it is crucial that the child and their parents have access to psychological support.
Lead researcher Anne Haughstvedt said: 'We hope that our findings will help identify the type of support that children with diabetes and their parents should receive.'