Cigarette smoking is independently associated with markers of endothelial dysfunction and hyperinsulinaemia in nondiabetic individuals with coronary artery disease.Curr Med Res Opin. 2001; 17(2):132-41.CM
Oxidative stress and endothelial dysfunction have been introduced as a unifying pathological mechanism for early atherosclerotic disease. They are caused by a variety of stimuli including cigarette smoking (environmental) and type 2 diabetes (disease factor). However, the role of hyperinsulinemia, a marker of insulin resistance, as a risk factor for atherosclerosis remains to be clarified.
To study the relationship of smoking, hyperinsulinaemia and biochemical markers of oxidative stress and endothelial dysfunction, in patients with coronary artery disease.
Case-control study of 5-year survivor status in smokers, former smokers and nonsmokers with angiographically documented stable coronary artery disease classified by self-reporting of smoking status together with plasma cotinine measurements.
Cardiology and cardiac surgery unit of a tertiary care referral centre.
PATIENTS AND METHODS
Plasma levels of vitamins C, E and selenium, and the adhesion molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were assessed in 214 patients at baseline together with the glucose and insulin response to an oral glucose challenge. Sixty known or newly diagnosed type 2 diabetic patients (28%) were identified and excluded from further analysis.
E-selectin and ICAM-1, serving as markers of endothelial dysfunction, significantly correlated with hyperinsulinaemia (p < 0.05). Circulating immunoreactive insulin was elevated in active smokers and former smokers as compared to non-smokers after an oral glucose load (p < 0.05 for the area under the insulin time curve), despite a similar glucose response. Smoking was associated with a decrease in antioxidant vitamins C (p = 0.02) and E (p = 0.03), and an increase of E-selectin (p < 0.05) and ICAM-1 (p < 0.001). Low baseline ICAM-1 and high vitamin C levels emerged as the most significant multivariate predictors of 5-year survival (p < 0.001).
Hyperinsulinaemia in smokers is linked with markers of endothelial dysfunction. Impaired vascular reactivity can thus be a new possible mechanism linking insulin resistance and smoking.