Did you know that smoking triples your risk of having a heart attack and doubles your risk of having a stroke? Or that the lifespan of smokers is reduced by 10 years when compared to non-smokers?
Tobacco use has no known health benefits. On the contrary, it causes disease, disability and premature death, and there’s no risk-free level of exposure. Tobacco smoke is made up of a complex mixture of more than 7 000 chemicals, including several cancer-causing substances.
In the 20th century, the tobacco epidemic killed 100 million people worldwide. During the 21st century, it could kill one billion – if current trends continue.
In the short run, cigarette smoking damages your overall health, making you more susceptible to acute illnesses (e.g. colds and flu), respiratory symptoms, and absence from school or work. It causes inflammation in the body, impairs your immune system, makes it harder for your body to repair wounds, and changes the lipid (fat) profile in your blood. Over time, the effects are more devastating.
Tobacco use is a risk factor for six of the eight leading causes of death in the world:
• Coronary heart disease (heart problems caused by narrowed arteries)• Cerebrovascular disease (disease of the blood vessels and the arteries that supply the brain)• Lower respiratory infections• Chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema • Tuberculosis (TB)• Trachea, bronchus and lung cancers
Coronary heart disease
Research has consistently shown that there’s a strong link between cigarette smoking and coronary heart disease (when your coronary arteries become narrowed by a gradual build-up of fatty material within their walls).
As a result, smokers are at greater risk of experiencing heart attacks than non-smokers. The excess risk among middle-aged smokers is approximately two-fold. In other words, smokers are almost twice as likely to have heart attacks compared to people who have never smoked.
• Damages the lining of the arteries, leading to a build-up of fatty deposits that narrow these blood vessels.• Reduces the amount of oxygen in the blood. This means your heart has to pump harder to supply your body with the oxygen it needs.• Stimulates the body to produce adrenaline. This makes your heart beat faster and raises your blood pressure.• Makes your blood more likely to clot. This increases your risk of having a heart attack or stroke.
Cigarette smoking has long been identified as a major cause of cerebrovascular disease. This refers to disease of the blood vessels that supply the brain.
The most common presentations of cerebrovascular disease are ischaemic and haemorrhagic strokes. An ischaemic stroke occurs when a blood clot, or other blockage, cuts off the blood supply to the brain.
During a haemorrhagic stroke, an artery in or on the surface of the brain ruptures or leaks, causing bleeding and damage in or around the brain.
The impact of smoking is proportionally larger in relatively younger adults. Among 35- to 64-year-olds, more than 40% of all cerebrovascular disease deaths are attributable to cigarette smoking.
Lower respiratory infections
While cigarette smoking is commonly associated with coughing, phlegm, wheezing and difficulty breathing, it’s also closely linked to serious lower respiratory infections such as bronchitis and pneumonia, and bronchiolitis in infants – mostly because of its detrimental effect on the immune system.
In addition, teenagers who smoke cigarettes are more likely to experience impaired lung growth, earlier decline in lung function, and asthma-related symptoms.
Among adults who smoke cigarettes, lung function also begins to decline at a younger age, while the age-related decline in lung function occurs faster.
Chronic obstructive pulmonary disease
The process of inhaling cigarette smoke brings your respiratory system into direct contact with a wide range of toxins. It’s therefore not surprising that smoking’s harmful effects on the respiratory system extend well beyond lung cancer.
A group of diseases that’s closely linked to smoking is chronic obstructive pulmonary disease (COPD) – an umbrella term used to describe progressive lung diseases including emphysema, chronic bronchitis and non-reversible asthma.
Tobacco smoking is a major risk factor for this group of diseases. Approximately 20% of smokers develop COPD.
A strong link has been observed between cigarette smoking and risk for tuberculosis (TB) infection. Once a smoker has been infected with the tuberculosis bacteria, there’s also an increased risk of progression to active TB disease.
Tobacco smoking is estimated to account for one-fifth of all TB cases globally, even in South Africa where the annual TB incidence rate is among the highest in the world and where HIV is the dominant risk factor.
Worldwide, a considerable proportion of cancer cases can be attributed to smoking. Smoking can cause cancer almost anywhere in the body. This includes the nose and sinuses, the mouth, the upper throat, the larynx, the oesophagus, the bladder, the ovaries, the cervix, the kidneys, the liver, the stomach, the bowel, and the pancreas. It also increases one’s risk for leukaemia.
American health authorities recognised smoking as a cause of lung cancer as early as 1964. The risk of lung cancer among heavy smokers may be as high as 30%, compared with a lifetime risk of 1% or less in those who have never smoked.
In developed countries, 90% of all cases of lung cancer is caused by smoking. Smoking can increase the risk of men developing lung cancer by up to 25 times, and the risk is even higher for female smokers. Unfortunately, lung cancer survival is one of the lowest of all cancers.
The more cigarettes you smoke a day, the higher your risk of cancer. Former smokers still have an increased risk of cancer, even though the risk declines over time. Studies have shown that smokers who have been abstinent for more than 15 years had an 80 to 90% reduction in lung cancer risk.
The dangers of second-hand smoking
Did you know that the smoke that burns from a cigarette contains more harmful substances than the smoke inhaled by a smoker? Second-hand smoke is incredibly dangerous.
The diseases caused by or linked to second-hand smoking can be summarised as follows:
| Children|| Adult|
| During pregnancy: impaired foetal growth and neurological development || Stroke|
| Middle ear disease and recurrent middle ear infections|| Nasal irritation and nasal sinus cancer|
| Lymphoma|| Coronary heart disease|
| Respiratory symptoms and impaired lung function|| Reproductive effects in women: low birth weight, pre-term delivery|
| Asthma|| Lung cancer|
| Sudden infant death syndrome (SIDS)|| Atherosclerosis|
| Leukaemia|| Chronic respiratory symptoms, worsening of asthma symptoms, impaired lung function|
| Lower respiratory illness: bronchitis and pneumonia || |
| Increased risk for lung cancer and cardiovascular disease (heart disease and stroke) in adulthood (from second-hand smoke inhalation in children)|| |
Source: US Department of Health and Human Services
Reviewed by Cape Town-based general practitioner, Dr Dalia Hack. October 2018.