Effect of oral insulin on insulin autoantibody levels in the Diabetes Prevention Trial Type 1 oral insulin study.
OBJECTIVE
Our aim was to evaluate insulin autoantibody (IAA) levels over time in the Diabetes Prevention Trial Type 1 (DPT-1) oral insulin study to determine the effect of oral insulin compared with placebo on IAA levels.


METHODS
The DPT-1 trial randomised 372 relatives of subjects with type 1 diabetes, positive for IAA and with normal IVGTTs and OGTTs, to oral insulin 7.5 mg daily or placebo. Subjects were followed with IVGTTs, OGTTs and serial IAA measurements. The change in IAA level over time was modelled statistically using mixed model longitudinal data analysis with spatial exponential law for unevenly spaced data. In a separate analysis, subjects were divided into four groups by treatment and diabetes status at the end of the study. IAA levels were compared amongst the groups at randomisation, last sampling and at the maximum level.


RESULTS
Longitudinal data analysis showed that treatment did not affect levels of IAA over time. After controlling for age, the IAA levels at randomisation and the last visit and the maximum values were different in the four groups. Significantly higher levels were noted in groups that developed diabetes compared with those that did not, with no significant difference by treatment group.


CONCLUSIONS
This suggests that IAA levels over time were not influenced by oral insulin in subjects already positive for IAA at the start of treatment.
Barker
J M
JM
Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, CO, USA. jennifer.barker@uchsc.edu
McFann
K K
KK
Orban
T
T
D000284:Administration, Oral; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy* / Q000517:prevention & control; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D007328:Insulin / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use*; D007330:Insulin Antibodies / Q000097:blood*; D008297:Male; D013997:Time Factors
D007004:Hypoglycemic Agents; D007328:Insulin; D007330:Insulin Antibodies