Cigarette smoking increases which property of blood that contributes to atherogenesis?

• A. Decreases viscosity
• B. Increases viscosity
• C. Has no effect on viscosity
• D. Decreases inflammation

Answer: (B)

Smoking increases blood viscosity. This occurs as cigarette smoke promotes a rise in red cell mass (carbon monoxide–related hypoxia triggers more red cell production) and elevates plasma proteins such as fibrinogen, thickening the blood. The resulting hyperviscosity slows flow and increases endothelial shear stress, which along with heightened prothrombotic and inflammatory states, promotes the vascular changes seen in atherogenesis. So the property that increases is viscosity; smoking does not decrease viscosity, and it tends to worsen inflammatory and thrombotic activity rather than reduce it.