Plasma interleukin-6 levels are increased in subjects with impaired glucose tolerance but not in those with impaired fasting glucose in a cohort of Italian Caucasians.
BACKGROUND
While the relationship between impaired glucose tolerance (IGT) and circulating interleukin-6 (IL-6) is well established, there is no information whether IL-6 levels are elevated in impaired fasting glucose (IFG).


METHODS
To this end, we examined the relationship between plasma IL-6 concentration and different degrees of glucose homeostasis in a cohort of 470 Italian Caucasian subjects comprising 236 normal glucose tolerant (NGT), 49 IFG, 51 IGT, and 134 type 2 diabetic subjects.


RESULTS
We observed that IL-6, CRP and fibrinogen levels were higher in subjects with IGT or type 2 diabetes as compared with NGT and IFG subjects. Univariate correlations between IL-6 concentrations and metabolic variables in the whole cohort showed that IL-6 levels were positively correlated with age, BMI, waist, systolic and diastolic blood pressure, fasting plasma glucose, triglycerides, CRP, fibrinogen, and negatively correlated with insulin sensitivity, IGF-I and HDL. In a subgroup analysis including NGT, IFG and IGT (n = 336), IL-6 levels were positively correlated with age, BMI, waist, systolic and diastolic blood pressure, triglycerides, CRP, fibrinogen, fasting insulin, 2 h post-load glucose, and negatively correlated with insulin sensitivity, IGF-I and HDL. Stepwise linear regression analysis in a model including gender, age, BMI, waist, glucose tolerance status, fasting plasma glucose, 2 h post-load glucose, triglycerides, HDL, fasting insulin, and insulin sensitivity revealed that waist was the only independent variable associated with IL-6 levels accounting for 21.0% of its variation (P < 0.0001).


CONCLUSIONS
These data show that IGT and type 2 diabetes, but not IFG, are associated with elevated plasma IL-6 levels.
Cardellini
Marina
M
Department of Internal Medicine, University of Rome-Tor, Vergata 00133, Rome, Italy.
Andreozzi
Francesco
F
Laratta
Emanuela
E
Marini
Maria Adelaide
MA
Lauro
Renato
R
Hribal
Marta Letizia
ML
Perticone
Francesco
F
Sesti
Giorgio
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005215:Fasting; D005260:Female; D018149:Glucose Intolerance / Q000097:blood*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D007558:Italy; D008297:Male; D008875:Middle Aged; D044465:White People
D001786:Blood Glucose; D015850:Interleukin-6