Tobacco smoking is a known or probable cause of approximately 25 diseases, and even the WHO says that its impact on world health is not fully assessed. Heart attack and stroke UK studies show that smokers in their 30s and 40s are five times more likely to have a heart attack than non-smokers. Tobacco contributes to the hardening of the arteries, which can then become blocked and starve the heart of bloodflow, causing the attack. Often, smokers who develop this will require complex and risky heart bypass surgery.
Smoking also increases the risk of having a stroke.
Another primary health risk associated with smoking are lung cancer, which kills more than 20,000 people in the UK every year. US studies have shown that men who smoke increase their chances of dying from the disease by more than 22 times. Women who smoke increase this risk by nearly 12 times. Lung cancer is a difficult cancer to treat - long term survival rates are poor. Smoking also increases the risk of oral, uterine, liver, kidney, bladder, stomach, and cervical cancers, and leukaemia.