Cigarette smoking as a preventable cause of disease

Tobacco smoking is the inhalation of smoke from burned dried or cured leaves of the tobacco plant, most often in the form of a cigarette. Cigarette smoke contains a toxic collection of more than 4000 chemicals including nicotine, which combined give rise to addictive stimulant and euphoriant properties. According to the World health Organization, about one-third of the world's male population smokes tobacco and cigarette smoking (CS) killed 100 million people worldwide in the 20th century. Therefore, CS is considered a major cause of preventable morbidity and mortality worldwide.1 2 There are three main clinical consequences of prolonged exposure to CS. First, it causes several chronic respiratory ailments, including chronic bronchitis, emphysema and lung fibrosis, and is associated with an increase in respiratory infections.3 Second, it is associated with an increased incidence of a variety of cancers including lung, oral, oesophagus, pancreas and colon.4 And third, CS increases the risk of atherothrombotic clinical events such as myocardial infarction and stroke.5 The risk of death in these patients increases with increasing exposure to cigarette smoke, measured by the number of cigarettes smoked daily, the duration of smoking, the degree of inhalation and the age of initiation. In addition, exposure to environmental tobacco smoke in non-smokers is associated with an increased risk of cardiovascular events and asthma.6 7 There is convincing evidence that smoking cessation has beneficial effects, even after a cardiovascular event.5–8 In the last decade, health authorities have made a considerable effort to promote smoking cessation. Although the prevalence of smoking has declined over the last few decades in developed countries, it is rapidly increasing in developing countries, with an emerging epidemic of tobacco-related diseases.9

Hepatologists have traditionally paid scant attention to the deleterious effects of CS.10 This reflects the fact that …