Smoking causes about 30% of all cancer deaths in the USA, and 1 in 4 in the UK. A study done in South Africa warns that for those who started smoking in their teens, there is a 50% chance of dying of a smoking related disease by the age of 60.
Chemicals in cigarette smoke enter the blood stream and can affect the entire body, not only the respiratory tract and the lungs. (See diagram below.) These chemicals can cause damage to our DNA, including the genes that are supposed to protect us against cancer, for example tumour suppressor genes. The build-up in damage to the same cells over time contributes to the risk of cancer. Smoking has been linked to various types of cancer, with lung cancer as the highest risk of all.
Lung cancer is the leading cause of cancer deaths in the USA and is one of the hardest cancers to treat. Smokers have a much higher risk of lung cancer, with smoking resulting in about 80% of cases of lung cancer. The type of cigarette, such as low tar or filters, or smoking cigars or a pipe, make very little difference. The higher the number of cigarettes per day the more adverse the effect, and the number of years you spend smoking vastly increases the risk of cancer.
A colleague (heavy smoker) used to say that from 6 to 7 in the morning nobody should bother him, as that is his coughing time! The typical “smoker’s cough” results from the chemicals and particles that irritates the airways and lungs. The American Cancer Society describes it as follows: “Normally, tiny hair-like structures (called cilia) in the airways help sweep harmful material out of the lungs. But tobacco smoke slows the sweeping action, so some of the particles in the smoke stay in the lungs and mucus stays in the airways. While a smoker sleeps (and doesn’t smoke), some cilia recover and start working again. After waking up, the smoker coughs because the lungs are trying to clear away the irritants and mucus that built up from the day before.”
Smoking damages the small air sacks and airways in the lungs and can lead to chronic obstructive pulmonary disease (COPD) – a long term lung disease that includes chronic bronchitis and emphysema.
Chronic bronchitis is characterized by the airways making too much mucus, forcing the person to cough it out. The cough over time becomes chronic. The airways get blocked by scar tissue and mucus, and can lead to bad lung infections.
Emphysema slowly destroys a person’s ability to breathe as the walls between the small air sacks in the lungs – that help oxygen get into the blood – breaks down and create larger but fewer sacks. Over time these sacks break down to the point where very little oxygen reaches the blood. People with this disease suffer immensely, grasping for breath and feeling as if they are suffocating, literally slowly dying from a lack of oxygen.
“Cancer cures smoking!”
Health risks of smoking tobacco. Article published (last reviewed 12 November 2015) by the American Cancer Society.
How smoking causes cancer. Article published (last reviewed 4 August 2016) by Cancer Research UK.
SA smoking study reveals shocking details. Article on research by the Chronic Disease Initiative for Africa (CDIA), published on News 24 on 19 September 2013.