Associations between plasma insulin-like growth factor-I and the markers of inflammation interleukin 6, C-reactive protein and YKL-40 in an elderly background population.
OBJECTIVE
The objective of the present study was to test the hypothesis that circulating levels of insulin-like growth factor-I (IGF-I) are inversely associated with inflammatory processes in an elderly background population.


METHODS
We conducted a population-based study comprising 629 individuals, aged 50-89 years. Associations between plasma IGF-I versus interleukin 6 (IL-6) and the acute phase proteins high sensitive C-reactive protein (hsCRP) and YKL-40 were evaluated by linear regression analyses. Subsequently, the population was dichotomised at a CRP level of 3.0 mg/L and the associations were re-evaluated in the two subgroups.


RESULTS
Adjusted for confounding variables, plasma IGF-I was inversely related to IL-6, hsCRP and YKL-40 (all P < 0.001). The strongest association was found for YKL-40 with a 34% reduction in YKL-40 per twofold increase in IGF-I. A significant inverse association between IGF-I and all markers of inflammation persisted in individuals with hsCRP below 3.0 mg/L whereas only YKL-40 was significantly associated with IGF-I in individuals with hsCRP above 3.0 mg/L.


CONCLUSIONS
The data support the hypothesis of an inverse association between GH/IGF-I signalling and inflammation, and suggest that the relationship between the IGF-I and inflammation might be more predominant in healthy individuals with a low inflammatory activity.
Andreassen
Mikkel
M
Department of Endocrinology, Herlev Hospital, University of Copenhagen, Denmark. andreassenmikkel@hotmail.com
Raymond
Ilan
I
Hildebrandt
Per
P
Kistorp
Caroline
C
Rathcke
Camilla
C
Vestergaard
Henrik
H
Faber
Jens
J
Kristensen
Lars Ostergaard
LO
D054392:Adipokines; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000378:metabolism*; D000071451:Chitinase-3-Like Protein 1; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007249:Inflammation / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D015850:Interleukin-6 / Q000097:blood*; D037102:Lectins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D044382:Population Groups; D015398:Signal Transduction / Q000502:physiology
D054392:Adipokines; D015415:Biomarkers; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D015850:Interleukin-6; D037102:Lectins; D007334:Insulin-Like Growth Factor I; D002097:C-Reactive Protein