Joint analysis of individual participants' data from 17 studies on the association of the IL6 variant -174G>C with circulating glucose levels, interleukin-6 levels, and body mass index.
BACKGROUND
Several studies have investigated associations between the -174G>C single nucleotide polymorphism (rs1800795) of the IL6 gene and phenotypes related to type 2 diabetes mellitus (T2DM) but presented inconsistent results.


OBJECTIVE
This joint analysis aimed to clarify whether IL6 -174G>C was associated with glucose and circulating interleukin-6 concentrations as well as body mass index (BMI).


METHODS
Individual-level data from all studies of the IL6-T2DM consortium on Caucasian subjects with available BMI were collected. As study-specific estimates did not show heterogeneity (P>0.1), they were combined by using the inverse-variance fixed-effect model.


RESULTS
The main analysis included 9440, 7398, 24,117, or 5659 non-diabetic and manifest T2DM subjects for fasting glucose, 2-hour glucose, BMI, or circulating interleukin-6 levels, respectively. IL6 -174 C-allele carriers had significantly lower fasting glucose (-0.091 mmol/L, P=0.014). There was no evidence for association between IL6 -174G>C and BMI or interleukin-6 levels, except in some subgroups.


CONCLUSIONS
Our data suggest that C-allele carriers of the IL6 -174G>C polymorphism have lower fasting glucose levels on average, which substantiates previous findings of decreased T2DM risk of these subjects.
Huth
Cornelia
C
Institute of Epidemiology, Helmholtz Zentrum Munchen, Neuherberg, Germany.
Illig
Thomas
T
Herder
Christian
C
Gieger
Christian
C
Grallert
Harald
H
Vollmert
Caren
C
Rathmann
Wolfgang
W
Hamid
Yasmin H
YH
Pedersen
Oluf
O
Hansen
Torben
T
Thorand
Barbara
B
Meisinger
Christa
C
Doring
Angela
A
Klopp
Norman
N
Gohlke
Henning
H
Lieb
Wolfgang
W
Hengstenberg
Christian
C
Lyssenko
Valeriya
V
Groop
Leif
L
Ireland
Helen
H
Stephens
Jeffrey W
JW
Wernstedt Asterholm
Ingrid
I
Jansson
John-Olov
JO
Boeing
Heiner
H
Mohlig
Matthias
M
Stringham
Heather M
HM
Boehnke
Michael
M
Tuomilehto
Jaakko
J
Fernandez-Real
Jose-Manuel
JM
Lopez-Bermejo
Abel
A
Gallart
Luis
L
Vendrell
Joan
J
Humphries
Steve E
SE
Kronenberg
Florian
F
Wichmann
H-Erich
HE
Heid
Iris M
IM