Fasting insulin levels independently associated with coronary heart disease in non-diabetic Turkish men and women.
BACKGROUND
Levels of plasma insulin have been recognized as a weak risk indicator for coronary or cardiovascular risk in the general population with ethnic background and gender modifying this relationship. We assessed whether insulin concentrations are associated with or would serve as a marker of prevalent coronary heart disease risk in a cross-sectional study of a population having low cholesterol levels (just under 5 mmol/l) but higher prevalence of components of the metabolic syndrome.


METHODS
In 688 participants of the Turkish Adult Risk Factor Survey in 2001, plasma insulin values as well as other risk variables were evaluated, and coronary heart disease was diagnosed based on clinical findings and Minnesota coding of resting electrocardiograms. Nearly equal numbers of men and women (>30 years of age) constituted the population sample from the two largest regions of Turkey. Concentrations of insulin were determined by the chemiluminescent immunometric method.


RESULTS
Geometric mean value was 50 pmol/l (interquartile range 37-68 pmol/l), without revealing a significant difference in genders. Fasting insulin was correlated in both genders with many variables, notably those involving central obesity, triglycerides, blood pressure, physical inactivity and, inversely, with high-density lipoprotein (HDL)-cholesterol. In a regression model, waist circumference and body mass index were strongly associated with log insulin, after controlling for age and presence of coronary heart disease. The age- and obesity-adjusted odds ratio for coronary heart disease in the highest as opposed to the lowest quartile was 2-fold in both genders (P<0.05). Even after adjustment for dyslipidemia, blood pressure, glucose intolerance, physical activity and smoking status, an over 2-fold increased coronary heart disease risk still persisted with regard to hyperinsulinemia (>or=10 mU/l, 69.5 pmol/l). When C-reactive protein which was correlated with fasting insulin only in women, was added to the model, the impact of hyperinsulinemia on coronary heart disease risk remained unchanged.


CONCLUSIONS
Hyperinsulinemia (i) may provide information on the coronary heart disease likelihood over and above that provided by the other risk factors, including HDL-cholesterol, and (ii) may contribute, within the frame of insulin resistance, to the coronary heart disease risk independently of the classical risk factors.
Onat
Altan
A
Department of Cardiology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey. tkd@ixir.com
Ceyhan
Köksal
K
Sansoy
Vedat
V
Basar
Omer
O
Erer
Burak
B
Uysal
Omer
O
Hergenç
Gülay
G
D000328:Adult; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D003327:Coronary Disease / Q000097:blood* / Q000208:ethnology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006946:Hyperinsulinism / Q000208:ethnology; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D014421:Turkey / Q000453:epidemiology
D007328:Insulin; D002097:C-Reactive Protein