Insulin dependent diabetic adolescent girls show a tendency towards ex
cess weight. The relationship between insulin resistance and body mass
index (BMI) was investigated in 23 Type 1 adolescents aged 13-20 yr.
These patients body mass indexes spanned from 19.8 to 30.5. Excess wei
ght was evaluated using Z-scores, corrected for age with reference to
french standards. 9 patients with a Z-score greater than 2 were consid
ered as obese. Insulin sensibity was measured using the hyperinsulinae
mic euglycaemic clamp (insulin infusion rate, 1 mU kg-1 min-1). The me
an glucose infusion rate during the clamp was low in the diabetic girl
s (2.29 +/- 1.35 mg kg-1 min-1), confirming the existence of insulin r
esist ce. However, the degree of insulin resistance was not correlated
with the excess in weight (glucose infusion rate, 2.23 +/- 1.24 vs 2.
33 +/- 1.46 mg kg-1 min-1 in the obese and the non-obese patients, res
pectively). None of the factors which influe on insulin sensivity coul
d explain this lack of correlation, the obese patients showing greater
daily insulin doses (1.36 +/- 0.22 vs 1.22 +/- 0.25 unit kg-1 day-1)
and worse metabolic control (Hba1C, 10.9 +/- 1.4 vs 10.2 +/- 2.0%). In
sulin resistance was significantly correlated with free fatty acid lev
els during the clamp.