Does C-reactive protein identify a subclinical metabolic disease in healthy subjects?
BACKGROUND
Highly sensitive C-reactive protein (hs-CRP) levels are significant predictors of subsequent diabetes and metabolic syndrome (MS). Owing the strong correlations between components of the MS and obesity with hs-CRP levels, previous studies about the associations of hs-CRP with insulin resistance might have been confounded by the inclusion of overweight or dysmetabolic subjects.


METHODS
Our aim was to evaluate the associations between hs-CRP levels and fasting insulin and insulin resistance (evaluated by the Homeostasis Model Assessment: HOMA IR) in a subgroup of subjects with normal body mass index (BMI) and without any metabolic abnormalities. Out of a cohort of 1658 middle-aged subjects, representative of the local sanitary districts of the province of Asti (north-western Italy) enrolled for metabolic screening: 241 (14.5%) showed normal BMI, glucose tolerance, blood pressure and waist values and no dyslipidaemia.


RESULTS
In this subgroup of subjects, those with hs-CRP levels > or = 3 mg L(-1) showed significantly higher median insulin and HOMA-IR values (respectively: 20.4 vs. 6.0 pmol L(-1), and 0.8 vs. 0.2 microU mL(-1)x mmol L(-1)). In a multiple regression model, insulin and insulin resistance remained significantly and independently related to hs-CRP levels, after adjustments for age, sex, BMI, waist, alcohol consumption, level of physical activity and smoking habits. Very few individuals within lower fasting insulin quartiles showed hs-CRP values > or = 3 mg L(-1) when compared with approximately 60% of those within the highest quartile.


CONCLUSIONS
The novel finding is that a state of low-grade systemic inflammation is present in normal BMI subjects who show subclinical insulin resistance but no other metabolic abnormalities.
Bo
S
S
University of Turin, Turin, Italy. sbo@molinette.piemonte.it
Gambino
R
R
Uberti
B
B
Mangiameli
M P
MP
Colosso
G
G
Repetti
E
E
Gentile
L
L
Cassader
M
M
Pagano
G F
GF
D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis*; D015331:Cohort Studies; D005260:Female; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000175:diagnosis*; D008875:Middle Aged
D007328:Insulin; D002097:C-Reactive Protein