Incorporation of the fasting free fatty acid concentration into quantitative insulin sensitivity check index improves its association with insulin sensitivity in adults, but not in children.
OBJECTIVE
Based on fasting insulin and glucose, several indices of insulin sensitivity have been developed in adults. Recently, it has been demonstrated that incorporation of the fasting free fatty acid (FFA) concentration improves the association with insulin sensitivity in adults. We investigated the association of clamp-derived insulin sensitivity with indices of insulin sensitivity derived from fasting blood in prepubertal children and adults, with and without incorporation of FFAs.


METHODS
We studied 59 healthy adults and 29 of them are prepubertal children. We measured insulin sensitivity with the euglycemic-hyperinsulinemic clamp. Based on fasting insulin and glucose, we estimated insulin sensitivity with the homeostasis model assessment (HOMA), the quantitative insulin sensitivity check index (QUICKI), and the revised QUICKI after the incorporation of FFAs.


RESULTS
The associations of HOMA and QUICKI with clamp-derived insulin sensitivity in children (r=-0.55 and 0.54 respectively; P<0.01) were similar to those in adults (r=-0.54 and 0.53 respectively; P<0.01). However, incorporation of FFAs into the QUICKI model resulted in an increase in the association in adults, but not in children (r=0.68 and 0.48 respectively; P<0.01). Adding FFA levels to a regression model with glucose and insulin as independent variables resulted in an increase in the explained variance in clamp-derived insulin sensitivity in adults, but not in children (P value 0.004 in adults and 0.3 in children).


CONCLUSIONS
HOMA and QUICKI are associated with clamp-derived insulin sensitivity in both children and adults. Incorporating fasting levels of FFAs into the QUICKI model improves the association with clamp-derived insulin sensitivity in adults, but not in children.
Department of Internal Medicine, Institute for Cardiovascular Research-Vrije Universiteit, VU University Medical Center, Amsterdam, The Netherlands. rg.ijzerman@vumc.nl
Richard G
RG
Ijzerman
Coen D A
CD
Stehouwer
Erik H
EH
Serné
Jasper J
JJ
Voordouw
Yvo M
YM
Smulders
Henriette A
HA
Delemarre-van de Waal
Mirjam M
MM
van Weissenbruch
D000328:Adult; D000367:Age Factors; D001786:Blood Glucose / Q000378:metabolism; D002648:Child; D005215:Fasting / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005260:Female; D015309:Glucose Clamp Technique; D006801:Humans; D007328:Insulin / Q000008:administration & dosage* / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin