Even after years of smoking cessation, levels of atherosclerosis [hardening of the arteries] are significantly higher in former smokers compared with never-smokers.

We saw there was a strong and direct relationship between arterial wall thickness and increasing levels of risk of former smoking.

How much you smoked matters more than how long ago you quit. Smokers should quit as soon as possible, and new smokers should be aware that there will be a lifelong risk. Cessation can reduce...