Insulin resistance and cigarette smoking

Area of Science:

• Endocrinology
• Cardiovascular Disease Research
• Metabolic Syndrome

Background:

• Cigarette smoking is linked to adverse lipid profiles, including elevated triglycerides and reduced high-density-lipoprotein-cholesterol.
• These lipid alterations are associated with increased coronary heart disease (CHD) risk and may be connected to insulin resistance and hyperinsulinemia.

Purpose of the Study:

• To investigate the relationship between chronic cigarette smoking and insulin-mediated glucose uptake.
• To compare lipid profiles, glucose-insulin responses, and insulin sensitivity between smokers and non-smokers.

Main Methods:

• Cross-sectional study involving 40 healthy volunteers (20 smokers, 20 non-smokers).
• Measurements included plasma lipid and lipoprotein concentrations, plasma glucose and insulin response to an oral glucose challenge, and insulin-mediated glucose uptake via a hyperinsulinemic-euglycemic clamp (simulated by glucose-insulin-somatostatin infusion).

Main Results:

• Smokers exhibited significantly higher very-low-density-lipoprotein (VLDL) triglycerides and cholesterol, and lower high-density-lipoprotein-cholesterol (HDL-C) compared to non-smokers.
• Despite similar plasma glucose levels post-oral glucose challenge, smokers demonstrated a significantly higher plasma insulin response.
• Smokers showed impaired insulin-mediated glucose uptake, evidenced by higher steady-state plasma glucose concentrations during a glucose-insulin-somatostatin infusion, despite comparable steady-state insulin levels.

Conclusions:

• Chronic cigarette smoking induces insulin resistance, hyperinsulinemia, and dyslipidemia in healthy individuals.
• These metabolic and lipid abnormalities in smokers may contribute to the elevated risk of coronary heart disease associated with smoking.