General household surveys in the UK have shown a continuing decline in the prevalence of cigarette smoking in men but not women: 44% of men and 34% of women aged 16 and over have smoked tobacco in some form. Manufactured cigarettes were smoked by an equal proportion of both sexes (34%). Cigarette smoking is now commonest between the ages of 16 and 24 years (42% in both sexes). At the age of 15 more girls (27%) than boys (18%) smoke cigarettes. A greater proportion of professional work ers than manual workers have given up smoking. In the USA the proportion of adult males who smoke is now only 36% and in women the prevalence is now 29%. Cigarette consumption is rising in Central and Eastern Europe and China in contrast to that in Western Europe and North America.
Cigarette smoking is addictive. Smoking nearly always begins in adolescence for psychosocial reasons and, once it is a regular habit, the pharmacological properties of nicotine play an important part in persistence, conferring some advantage to the smoker’s mood. Very few cigarette smokers (less than 2%) can limit themselves to occasional or intermittent smoking. The dangers are listed.
There is a significant dose-response relationship between the smoking of 0-40 cigarettes daily and lung cancer mortality. Sputum production and airflow limitation increase with daily cigarette consumption, and effort tolerance decreases, partly due to high levels of carboxyhaemoglobin in bronchitis patients. Smoking and asbestos exposure are synergistic in producing bronchial carcinoma, increasing the risk in asbestos workers by up to five to eght times that of non-smokers exposed to asbestos.
Cigarette smokers who change to other forms of tobacco are unlikely to reduce the risk, as they continue to inhale, and some of the highest levels of carboxyhaemoglob in have been found in cigar smokers. Environmental tobacco smoke-passive smoking-has been shown to cause more frequent and more severe attacks of asthma in children and possibly increases the number of cases of asthma. It is also associated with a small but definite increase in lung cancer.
Cigarette smoke contains polycyclic aromatic hydrocarbons and nitrosamines, which are potent carcinogens and mutagens in animals. It causes release of enzymes from neutrophil granulocytes and macrophages that are capable of destroying elastin and leading to lung damage. Pulmonary epithelial permeability increases even in symptomless cigarette smokers, and correlates with the concentration of carboxyhaemoglobin in blood. This altered permeability possibly allows easier access to carcinogens.
If the entire population could be persuaded to stop smoking, the effect on health care in the Western World would be enormous. National campaigns, bans on advertisement and a substantial increase in the cost of cigarettes are the most certain ways of achieving this. Only one in five general practitioners actively encourage their patients to give up smoking, yet simple advice and follow-up can motivate some 50% of their patients to stop. In smoking withdrawal clinics, success rates of 80% can be achieved in the first month. though only 15-20% of patients remain abstinent in the long term. Nicotine chewing gum has been advocated but is probably no better than verbal advice. Nicotine patches are available over the counter and better than placebo in helping smokers stop, though they must not be used by those suffering from heart disease, Chest symptoms usually have to be severe to stop patient from smoking.