No smoke without fire
Many people continue to smoke despite knowing it is bad for them. Do they understand the risks they are exposing themselves to?
SMOKING causes fatal lung cancer, says one. Smoking kills, says another.
There is certainly no mistaking the warnings that are now printed on cigarette packets in many parts of the world.
However, in spite of this, many people continue to smoke.
Do they understand the risks they are exposing themselves to?
Here, some experts spell it out.
How does smoking increase the risk of developing cancer?
Tobacco smoke contains nearly 5,000 chemical substances, roughly 90 of which are either proven or presumed carcinogens, according to Germany’s Federal Centre for Health Education (BZgA).
When you smoke, they are swallowed, inhaled, and also absorbed by mucous membranes – for example, in the respiratory and gastrointestinal tracts.
How do these substances cause cancer?
Cell division in the body, an essential biological process for growth, replenishment and reproduction, is strictly controlled by genes in molecules of DNA, or deoxyribonucleic acid, which contain all of the instructions that cells need to sustain themselves.
Carcinogenic substances in tobacco smoke can damage the DNA, and thereby, cause cells to multiply in different ways and invade other tissues.
Although cells can usually repair DNA damage, the toxic chemicals in cigarette smoke also impair the DNA repair mechanisms in smokers.
What types of cancer in particular does smoking cause?
Cigarette smoke damages the DNA in places where it comes into direct contact with tissue, so that means the mouth, throat and lungs.
Carcinogenic substances can also circulate in the body and lead to tumours elsewhere. Smokers are at especially high risk of cancers of the lungs, larynx, oesophagus and mouth.
Smoking is also linked to leukaemia, as well as cancers of the pancreas, kidneys, bladder and cervix.
How high is the cancer risk?
Smoking is responsible for 25% to 30% of all cancer deaths, the BZgA says.
According to the German Cancer Research Centre (DKFZ), about 10% of all smokers develop lung cancer during their lifetime, on average between 30 and 40 years after starting to smoke.
The longer and more heavily a person smokes, the greater the risk.
How many people die annually due to tobacco consumption?
Tobacco kills more than seven million people each year, and up to half of its users, says the World Health Organization.
More than six million of those deaths are from direct tobacco use, while about 890,000 are the result of non-smokers being exposed to second-hand smoke – be it due to lung cancer, coronary heart disease or stroke.
Will quitting smoking cut a long-time smoker’s cancer risk?
Yes. After an abstinence of several years, the risk of most types of cancer drops considerably.
According to the DKFZ, a decade after quitting, ex-smokers have cut their risk of developing lung cancer in half. Reaching the risk level of a non-smoker takes 20 to 30 years, however.