The development of type 1 diabetes may be linked to viral infections, experts have suggested.
A review of existing studies has indicated that people with diabetes are around nine times more likely to have had enterovirus than those without the condition.
Researchers from Sydney, Australia said that while the findings 'cannot prove" that enterovirus infection causes diabetes, the results provide 'additional support to the direct evidence of enterovirus infection in pancreatic tissue of individuals with type 1 diabetes'.
They reviewed 24 studies involving more than 1,900 people with type 1 diabetes or pre-diabetes.
Most of the participants were children, the time when type 1 usually develops.
Results published in the British Medical Journal (BMJ) show a strong connection between diabetes and enterovirus - a collection of viruses which can cause a range of symptoms, including fever, cold, rash, sickness and diarrhoea.
The authors concluded: 'Our results show an association between type 1 diabetes and enterovirus infection, with a more than nine times the risk of infection in cases of diabetes and three times the risk in children with autoimmunity.
'The odds of having an enterovirus infection in people with established diabetes suggest that persistent enterovirus infection is also common among patients with type 1 diabetes.'
Type 1 diabetes is believed to be caused by a complex relationship between genetic factors, the immune system and the environment.
Some 300,000 people in the UK have type 1 diabetes.