Determinants of growth in diabetic pubertal subjects.
OBJECTIVE
To analyze the relationship among metabolic control, IGF-I, and growth in pubertal diabetic subjects.


METHODS
In 72 diabetic children, we have studied the pattern of change of IGF-I, IGF-I SD score, IGF binding protein (BP)-1, and growth rate in different pubertal stages and have analyzed their relation to age sex, weight/length index, HbA1c, insulin concentration, insulin dose, and dehydroepiandrosteronesulfate (DHEAS).


RESULTS
The serum IGF-I values increased up to Tanner stage 4 and thereafter decreased, whereas IGFBP-1 showed the inverse pattern. When transforming the IGF-I values into SD scores, correcting for age, sex, and pubertal stage, it was shown that the deviation from normal values increased with increasing pubertal stage in boys, but was equal in stages 3-5 in girls. Using multiple regression analysis, HbA1c, insulin dose, and DHEAS were significantly correlated to IGF-I SD score (R2 = 0.253, P = 0.001). IGFBP-I levels in the afternoon were within normal range. LogIGFBP-1 showed an inverse correlation, to insulin concentration in single correlation (r = -0.26, P = 0.02). In single correlation, growth rate correlated significantly to insulin dose (r = 0.25, P = 0.03). In a multiple regression analysis, only DHEAS and IGF-I SD score were found to be significantly correlated to growth rate (R2 = 0.370, P < 0.001). The 18 adolescents who had reached their final height did not deviate from their target final height, according to their recorded growth since birth.


CONCLUSIONS
In a group of fairly well-controlled diabetic children, the normal increase in IGF-I during puberty is blunted. Despite decreased IGF-I levels, target final height was attained, probably because of adequate insulin compensation leading to normal IGFBP-l, thus adequate bioavailability of IGF-I. Our results point out the importance of sufficient exogenous insulin in the period of rapid linear growth.
Zachrisson
I
I
Department of Pediatrics, Danderyd Hospital, Sweden. ingmar.zachrisson@bar.ds.sll.se
Brismar
K
K
Hall
K
K
Wallensteen
M
M
Dahlqvist
G
G
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001827:Body Height; D015992:Body Mass Index; D002648:Child; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D003920:Diabetes Mellitus / Q000097:blood* / Q000188:drug therapy; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006128:Growth; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D007328:Insulin / Q000627:therapeutic use; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D011627:Puberty / Q000097:blood*; D011863:Radioimmunoassay; D012727:Sex Characteristics; D013548:Sweden
D015415:Biomarkers; D019314:Dehydroepiandrosterone Sulfate; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D007334:Insulin-Like Growth Factor I