Nasal administration of insulin to infants and children who are at high risk of developing type I diabetes due to their genetic profile and the presence of autoantibodies* does not prevent the condition developing. This is the conclusion of an Article published early Online and in an upcoming edition of The Lancet, written by Drs Kirsti Näntö-Salonen and Olli Simell, University of Turku, Finland, and colleagues.
In a mouse model of autoimmune (type I) diabetes, the incidence of the disease is reduced by insulin therapy via several routes, especially in young animals in the early stages of the disease.
At three hospitals in Finland, the researchers analysed cord blood samples of 116 720 infants (index), and 3430 of their siblings, for the genetic profile showing them to be susceptible to type I diabetes. This increased risk profile was found in 17397 of the index infants and 1613 of the siblings, of whom 11225 and 1574, respectively, consented to screening for diabetes-associated autoantibodies* at every 3-12 months. A total of 264 children (224 index /40 siblings) entered the randomised controlled part of the study, having tested positive for two or more autoantibodies in consecutive samples. Of these, 115 index/22 siblings were in the insulin group (dose 1 unit/kg), and 109 index/18 siblings in the placebo group. Median duration of intervention was 1.8 years.
The researchers found that similar numbers of index children from both groups were diagnosed with type I diabetes : 49 insulin versus 47 placebo; 42 and 38 of these children, respectively, continued treatment until diagnosis, with yearly rates of diabetes onset of 16.8% and 15.3%. Seven siblings were diagnosed with diabetes in the insulin group, versus six in the placebo group; while overall in all randomised children there were 56 diabetes diagnoses in the insulin group versus 53 in the placebo group. The authors conclude: "Administration of nasal insulin did not delay or prevent type I diabetes in children with genetically conferred risk of disease, even when started soon after antibodies to the condition were detected."
In an accompanying Comment, Dr David B Dunger and Dr John Todd, University of Cambridge, UK, say: "As Näntö-Salonen and colleagues and others have shown, autoantibody seroconversion in the first 1�� years of life may be a common prerequisite for development of type 1 diabetes, which would suggest that an early window of susceptibility exists, after which seroconversion and type 1 diabetes are much less likely."
Dr Kirsti Näntö-Salonen, University of Turku, Finland T) +358-40-833-8863 E) Kirsti.nanto-salonen@tyks.fi
Dr Olli Simell, University of Turku, Finland T) +358-40-567-0621 E) olli.simell@utu.fi
Dr David B Dunger and Dr John Todd, University of Cambridge, contact be e-mail only E) dbd25@cam.ac.uk / john.todd@cimr.cam.ac.uk
Notes to editors: Autoantibodies: The detection of diabetes-associated autoantibodies is the first recognisable sign of the ongoing autoimmune process.
Full Article and Comment: http://press.thelancet.com/nasalinsulinfinal.pdf
Journal
The Lancet