PASSIVE SMOKING – ITS HEALTH CONSEQUENCES

PASSIVE SMOKING – ITS HEALTH CONSEQUENCES

Cigarette smoking is a major independent risk factor for coronary artery disease. Retrospective and prospective epidemiologic studies have demonstrated a strong relationship between smoking and coronary morbidity and mortality in both men and women. The coronary disease death rate in smokers is 70% higher than in nonsmokers, and the risk increases with the amount of cigarette exposure. The risk of sudden death is two to four times higher in smokers. Smoking is also a risk factor for cardiac arrest and severe malignant arrhythmias. In addition to increased coronary mortality, smokers have a higher risk of nonfatal myocardial infraction or unstable angina. Patients with angina lower their exercise tolerance if they smoke. Woman who smoke and use oral contraceptives or post menopausal estrogen replacement greatly increase their risk of myocardial infraction.

Autopsy studies demonstrate more atheromatous changes in smokers than nonsmokers. Carbon monoxide in cigarette smoke decreases oxygen delivery to endothelial tissues. In addition, smoking may trigger acute ischemia. Carbon monoxide decreases myocardial oxygen supply, while nicotine increases myocardial demand by releasing catecholaminesthatraise blood pressure, heart rate, and contractility. Carbon monoxide and nicotine also induce platelet aggregation that may cause occlusion of narrowed vessels.

Cigarette smoking is the most important risk factor for peripheral vascular disease. In patients with intermittent claudication, smoking lowers exercise tolerance and may shorten graft survival after vascular surgery. Smokers have more aortic atherosclerosis and an increased risk of dying from a ruptured aortic aneurysm. Smokers under the age of 65 have a higher risk of dying from cerebrovascular disease and women who smoke have a greater risk of subarachnoid hemorrhage, especially if they also use oral contraceptives.

Cigarette smoking is the primary cause of chronic bronchitis and emphysema. Smokers have a higher prevalence of respiratory symptoms than non smokers. Studies of pulmonary function indicate that impairment exists in asymptomatic as well as symptomatic smokers. Smokers have a higher risk of acute as well as chronic pulmonary disease. Inhaling cigarette smoke impairs pulmonary clearance mechanisms by paralyzing ciliary transport. This may explain the susceptibility to viral respiratory infections, including influenza. Smokers who develop acute respiratory infections have longer and more severe courses, with a more prolonged cough.

Smokers have a higher prevalence of peptic ulcer disease and a higher case fatality rate. Smoking has been associated with increased osteoporosis in men and post menopausal women. Female smokers weigh less than non smokers and have an earlier age of menopause; both of these factors are associated with osteoporosis and may contribute to the relationship between smoking and osteoporosis. Moreover, smoking depresses serum estrogen levels in post menopausal women taking estrogen replacement therapy.

PASSIVE SMOKING / ENVIROMENTAL SMOKE EXPOSURE

Nonsmokers involuntarily inhale the smoke of nearby smokers, a phenomenon known as passive smoking. Wives, children and friends of smokers are a highly risk prone group.

Inhalation of sidestream smoke (Sidestream smoke is the smoke issued from the burning end of a cigarette between puffs) by a non smoker is definitely more harmful to him than to the actual smoker as he inhales more toxins. This is because sidestream smoke contains three times more nicotine, three times more tar and about 50 times more ammonia.

Passive smoking (Ibid. The Hindu: Exposure of non smokers to Environmental Tobacco Smoke (ETS) is known as passive smoking.) (because of smoking by their fathers) could lead to severe complications in babies aged below two. It is pointed out that in India hospital admission rates are 28 per cent higher among the children of smokers. These children have acute lower respiratory infection, decreased lung function, and increased eczema and asthma and increased cot deaths (Ibid). Also, children of heavy smokers tend to be shorter.

Passive smoking is associated with an overall 23 per cent increase in the risk of Coronary Heart Disease (CHD) among men and women who had never smoked. The following data shows just how heavy is cigarette smoking’s toll on non smokers.

A new “meta analysis” of data from 14 studies involving 6,166 individuals with coronary heart disease (CHD) finds that:

A] passive smoking was associated with an overall 23% increase in the risk of CHD among men and women who had never smoked.

B] It is estimated that 35,000 to 40,000 non smokers’ death each year in the United States can be attributed to passive smoking (American Heart Association SMOKING  2 HRT 19th March, 1998 Page 1.) This underscores the need to eliminate passive smoking as an important strategy to reduce a societal burden of CHD.

C] The United Nations Health Agency insisted that passive smoking caused lung cancer and that an environmental tobacco smoke poses a positive health hazard. Research on the subject has found an estimated 16% increase in the risk of developing lung cancer among nonsmoking spouses of smokers and an estimated 17 per cent rise in risk for work place exposure.

D] The public is left high and dry over the risks of “second hand smoke” . (Reuter   World 10th March, 1998). For non smokers, the major source of carbon monoxide is from passively inhaled cigarette smoke.

E] Environmental Tobacco Smoke (ETS) has been shown to reduce lung function in children. Its irritant effect could not be ignored as this is the reason why most people object to being the victims of passive smoking. Patients with asthma find this irritant effect will worsen symptoms.

F] The most remarkable effect of Environmental Tobacco Smoke (ETS) is the development of lung cancer in passively exposed non smokers as shown by reports from Japan and Greece. Large number of controlled studies have confirmed a relative risk of developing lung cancer in passively exposed subjects. Estimates from the United States have suggested that 3000 to 5000 deaths per year from lung cancer can be attributed to passive smoking.

Maternal smoking during pregnancy increases risks to foetus and non smokers chronically exposed to tobacco smoke will suffer health hazards. Maternal smoking during pregnancy contributes to foetal growth retardation. Infants born to mothers who smoke weigh an average of 200g. less but have no shorter gestations than infants of nonsmoking mothers. Carbon monoxide in smoke may decrease oxygen availability to the foetus and account for the growth retardation. Smoking during pregnancy has also been linked with higher rates of spontaneous abortion, foetal death, and neonatal death. (Primary Care Medicine   Respiratory Problems; Health Consequences of Smoking, Nancy A. Rigotti, Page 167.)

When smoking occurs in enclosed areas with poor ventilation, such as in buses, bars, and conference rooms, high levels of smoke exposure can occur. Acute exposure to smoke contaminated air decreases exercise capacity in healthy non smokers and can worsen symptoms in individuals with angina, Chronic Obstructive Pulmonary Disease (COPD) or asthma.

Chronic exposure to smoky air occurs in the workplace and in the homes of smokers. Non smokers in smoky workplaces develop small airways dysfunction similar to that observed in light smokers. Compared to the children of non smokers, children whose parents smoke have more respiratory infections throughout childhood, a higher risk of asthma, and alterations in pulmonary function tests.

In recent studies of non smoking women, those married to smokers had higher lung cancer rates than those married to non smokers. Chronic smoke exposure may be associated with increased incidence of cardiopulmonary disease in non smokers

Environmental Tobacco Smoke (ETS) also contributes to respiratory morbidity of children. Increased platelet aggregation also occurs when a non smoker smokes or is passively exposed to smoke. Although Environmental Tobacco Smoke (ETS) differs from “mainstream smoke”(Main stream smoke” is the one that is exhaled by the smoker after inhalation.) in several ways, it contains many of the same toxic substances. Infants and toddlers may be especially at risk when exposed to Environmental Tobacco Smoke (ETS). Considering the substantial morbidity, and even mortality of acute respiratory illness in childhood, a doubling in risk attributable to passive smoking clearly represents a serious pediatric health problem. Exposure to ETS has been associated with increased asthma related trips to the emergency room of hospitals.

There is now sufficient evidence to conclude that passive smoking is associated with additional episodes and increased severity of asthma in children who already have the disease. Exposure to passive smoking may alter children’s intelligence and behaviour and passive smoke exposure in childhood may be a risk factor for developing lung cancer as an adult   (Active and Passive Tobacco Exposure : A Serious Paediatric Health Problem, Page 1).

Environmental Tobacco Smoke (ETS) contains more than 4000 chemicals and at least 40 known carcinogens. Nicotine, the addictive drug contained in tobacco leads to acute increase in heart rate and blood pressure. ETS also increases platelet aggregation, or blood clotting. It also damages the endothelium, the layer of cells that line all blood vessels, including the coronary arteries.

In addition, non smokers who have high blood pressure or high blood cholesterol are at even greater risk of developing heart diseases from ETS (exposure Ibid. Page 8.).

An investigation in Bristol has found that the children of smokers have high levels of cotinine, a metabolite of nicotine, in their saliva. The results indicated that children who had two smoking parents were breathing in as much nicotine as if they themselves were smoking 80 cigarettes a year.

A study published in the “New England Journal of Medicine” found that the children of smoking mothers were less efficient at breathing. A study conducted by the Harvard Medical School in Boston, concluded that passive exposure to maternal cigarette smoke may have important effects on the development of pulmonary function in children.

An important discovery is that the cocktail of chemicals in a smoky room may be more lethal than the smoke inhaled by the smoker. The “sidestream” smoke contains three times as much benezo (a) pyrene (a virulent cause of cancer) six times as much toluene, another carcinogen, and more than 50 times as much dimethylnitrosamine. It has been commented by Dale Sandier of the National Institute of Environmental Health Studies in the United States that the potential for damage from passive smoking may be greater than has been previously recognized.

Indirect or second hand, smoking causes death not only by lung cancer but even more by heart attack, the studies show.

The studies on passive smoking, as it is often called, also strengthen the link between parental smoking and respiratory damage in children. According to experts, there was little question that passive smoking is a major health hazard. What has swayed many scientists is a remarkable consistency in findings from different types of studies in several countries with improved methods over those used in the first such studies a few years ago. The new findings confirm and advance the earlier reports from the U.S. Surgeon General, who concluded that passive smoking caused lung cancer. According to Dr. Cedric F. Garrland, an expert in the epidemiology of smoking at the University of California at San Diego “the links between passive smoking and health problems are now as solid as any finding in epidemiology”. The newer understanding of the health hazards of passive smoking were underscored in a report at a world conference on lung health in Boston recently.

Dr. Stanton A. Glantz of the University of California at San Fransisco estimated that passive smoke killed 50,000 Americans a year, two thirds of whom died of heart disease. Passive smoking ranks behind direct smoking and alcohol as the third leading preventable cause of death.

Dr. Donald Shopland of the U.S. National Cancer Institute, who has helped to prepare the Surgeon General’s reports on smoking has said: “there’s no question” now that passive smoking is also a cause of heart disease. The new findings on passive smoking parallel recent changes in U.S. laws and rules that limit smoking in public places. In recent years, all but four States (Missouri. North Carolina. Tennessee and Wyoming) have passed comprehensive laws limiting smoking in public place. Only a decade ago many scientists were sceptical about the initial links between passive smoking and lung cancer.

Thus, it can be safely concluded that the dangers of passive smoking are real and broader than once believed and parallel those of direct smoke. It has long been established that smoking harms the health of those who smoke. Now, new epidemio logical studies  (Health   Evidence mounts on passive smoking (The Hindu Sunday, August 5,1990) and reviews are strengthening the evidence that it also harms the health of other people nearby who inhale the toxic fumes generated by the smoker, particularly from the burning end of the cigarette.