In fact, smoking has even been associated with higher rates of depression, insomnia, frequent headaches and chronic pain
For comparison, Nicorette gum, which the FDA approved in 1984 as a product to help people quit smoking, contains 2 to 4 milligrams of nicotine
It is thought that smoking impairs vascular endothelial function through a decrease in nitric oxide bioavailability induced by activation of oxidative stress and inflammation
This is the reason doctors advise pregnant women to quit smoking, as the effects of nicotine and other toxic substances present in cigarettes can even cause pregnancy loss
References (1) Press release: E-cigarettes around 95% less harmful than tobacco estimates landmark review (2) Electronic Cigarettes: Past, Present, and Future (3) Smoking - Help Me Quit: Are you Really Serious About Stopping Smoking