First-phase insulin release during the intravenous glucose tolerance test as a risk factor for type 1 diabetes.
OBJECTIVE
To determine the relationship between first-phase (1 minute + 3 minutes) insulin production during the intravenous glucose tolerance test (IV-GTT) and risk factors for developing type 1 diabetes.


METHODS
Relatives of persons with type 1 diabetes (n = 59,600) were screened for islet cell antibodies (ICAs). Subjects who had positive screening results underwent IV-GTT (> or =2 times), repeat ICA screening, insulin autoantibody (IAA) screening twice, and an oral glucose tolerance test.


RESULTS
Of the 59,600 subjects in the study, 2199 (3.69%) had positive findings on initial ICA test. IV-GTTs were performed in 1622 subjects, with children <8 years having the lowest first-phase insulin release (FPIR) and subjects 8 to 20 years of age having the highest FPIR. The FPIR was lower for subjects with a confirmed positive ICA test result or a positive IAA test result, subjects with higher titers of ICA or IAA, and subjects who had an abnormal (impaired or diabetic) oral glucose tolerance test result.


CONCLUSIONS
FPIR in the IV-GTT correlates strongly with risk factors for development of type 1 diabetes.
Chase
H P
HP
Barbara Davis Center, University of Colorado Health Sciences Center, Denver, USA.
Cuthbertson
D D
DD
Dolan
L M
LM
Kaufman
F
F
Krischer
J P
JP
Schatz
D A
DA
White
N H
NH
Wilson
D M
DM
Wolfsdorf
J
J
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000209:etiology*; D005951:Glucose Tolerance Test / Q000009:adverse effects*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008875:Middle Aged; D012307:Risk Factors
D007328:Insulin