Secondhand Smoke

Carrie Zarski RRT

Term Paper (April 1997)
Respiratory Therapy Program
Fanshawe College
London, Ontario, Canada
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ABSTRACT

"For years, smokers and nonsmokers have managed an uneasy truce: live and let live (or let die). You stay in your section and I'll stay in mine (but don't blow in this direction)"₁ This truce is crumbling due to articles on secondhand smoke being written that are geared toward educating both smokers and the nonsmokers on the hazardous and sometimes fatal effects of secondhand smoke. The issue of secondhand smoke has become more prevalent in many recent epidemiological studies which have begun to educate society and are trying to deter smokers from 'lighting up' and hopefully lean towards a smoke free environment. The public won't accept their neighbour's smoke as simply a nuisance or an irritant that gives them red eyes, a runny nose, mild headaches and aggravated allergies.

Studies in the past have focused on the effects of smoking only on those people who actually inhale their own cigarette's smoke. More recent findings are concluding that secondhand smoke is linked to lung cancer and heart disease. It also contributes to many respiratory ailments among fetuses, infants and children.

"Smokers are seriously endangering others as well as themselves and therefore they are deprived of their single most compelling argument, which is that their habbit is their own so kindly buzz off"₂ The facts are clear, society is no longer ignorant and nonsmokers want to protect themselves from this lifestyle disease by educating everyone on the true health hazards that secondhand smoke poses to all.

INTRODUCTION

The harm involved with secondhand smoke (SHS) goes well beyond the annoyance of the rank odour it leaves on furniture, within clothing and in the air. It is extremely dangerous and not merely a displeasure to nonsmokers. "Cigarettes kill 430,000 people per year, and the SHS fumes that nonsmokers breathe in kill another 53,000"₃ Obviously inhaled tobacco smoke is dangerous to everyone, and SHS exposure represents a significant threat to health which should not be ignored. In January 1993 the Environmental Protection Agency (EPA) classified SHS as a "known - not just a 'probable', or 'possible' - Group A human carcinogen"₄ Group A carcinogen is a universal classifications reserved for the select group of toxic substances that are known to cause cancer in humans. Carcinogen potential is measured by the quantity of genetic mutations that SHS causes in bacteria.₄ The EPA concluded that "cigarette fumes cause 3,000 lung cancer deaths each year in people who don't smoke. This conclusion is based on 30 epidemiological studies conducted worldwide"_1,3 SHS increases the nonsmokers risk for heart disease and often exacerbates symptoms of asthma, bronchitis and reduced lung function in children and labels SHS a known cause of middle-ear infections, a leading cause of childhood surgery."₆

MAINSTREAM vs SIDESTREAM SMOKE

The smoke that's emitted from the lit end of a cigarette, cigar or pipe can be broken down into two main components. "Mainstream smoke makes up approximately 20% and it is the smoke that the smoker draws into their lungs and them exhales. Sidestream smoke, which is the pale, whitish mixture that curls off the tip of the smoldering cigarette when the smoker isn't inhaling, forms the remaining 80% of the smoke.₇ The combination of mainstream and sidestream smoke form secondhand smoke, also known as Environmental Tobacco Smoke (ETS), as well as Passive or Involuntary Smoke. SHS is different from inhaled smoke. It consists mainly of the sidestream smoke. Sidestream smoke is considered the larger health hazard towards nonsmokers as it occurs as larger percentage and it has a "higher concentration of certain toxic substances, including several cancer causing ones, than mainstream smoke."₄ Mainstream smoke is not as hazardous to the nonsmoker because when the smoker inhales, his "lungs become a filter, retaining significant amounts of gases and solid particles that would otherwise be available to the nonsmoker"₈ Toxic compounds are presen6t in both mainstream and sidestream smoke, but these toxic compounds are emitted in different amounts because of differing combustion conditions. "Mainstream smoke is formed at a higher temperature, while much less oxygen is present when sidestream smoke is formed"₉ The duration of exposure to mainstream smoke is restricted to the time taken to smoke a cigarette, however it takes several hours to a day to clear the air of the harmful chemicals after a cigarette has been smoked. "Rooms that have been repeatedly exposed to smoke can have deposits of the tarry substances from cigarettes on the furniture, drapes, and walls which can continue to give off small amounts of toxic substances for days or weeks"₁₀ The major toxic agents occurring in sidestream and mainstream smoke are subdivided into those that occur in a gas phase and those that occur in a particulate phase. To see exactly what's in cigarette smoke, and the ratio of these substances in sidestream smoke versus mainstream smoke see table 1.

Without a doubt indoor air pollutant levels and the human exposure to them are significantly higher than outdoor levels. These levels of indoor air pollutants are of particular concern because it is "estimated that most people spend approximately 90% of their time indoors."₁₁ The majority of carcinogens' effects on the body accumulate to slowly to show measurable results. The amount of secondhand smoke inhaled is related to the risk and potential seriousness of the disease. EPA analysis shows SHS contains "4,000 compounds, including 43 known carcinogens and other hazardous substances."₁₂ The 1993 Surgeon General's report revealed that "as many as 35,000 - 40,000 premature deaths of nonsmokers occur annually as the result of exposure to SHS, and that passive smoke ranks behind active smoking and alcohol as the third leading cause of death in the United States."₁₃ SHS is a major component of indoor air pollution and a "significant, preventable source of disease and death to nonsmokers who involuntarily inhale the smoke."₁₉ SHS is considered the single most prevalent air contaminant to the environment and has been known to cause; eye irritation, nasal congestion, headaches, cough, sore throat, hoarseness, nausea, dizziness, increased heart rate and general discomfort to those who are exposed.₁₄

COMPONENTS OF SHS

Through chemical analysis, researchers have broken down SHS into its' different elements. "Pollutants such as carbon monoxide, sulfur oxides, nicotine, nitrogen oxides, pyrene, benzene, respiratory particulates, ammonia and formaldehyde are some of the products resulting from the combustion of tobacco and are documented as carcinogens or potential carcinogens."₁₃

carbon monoxide is found in car exhaust fumes. Benzene is a poison that is used in cleaning solvents. Benzopyrene is a carcinogen that is found in gasoline and road tar. Butane is found in lighter fluid. Cadmium is a toxic metal that is used to recharge batteries. Acetone is better known as a nail polish remover. Formaldehyde is a toxic, foul smelling gas that is used as a disinfectant or a preservative. Arsenic, a very poisonous chemical element used in insecticides. Ammonia produced by the decomposition of nitrogenous organic matter is used as an emulsifier. Nicotine is used as as insecticide in agriculture and as a parasiticide in veterinary medicine. It is obvious that not one of the above mentioned ingredients are good for your health.

Although nicotine is not classified as a carcinogen, it is toxic. It is a highly addictive substance associated with the ill effects of smoking.

Many people find smoking compelling because they find so many of its effects to be pleasurable. "Nicotine is a powerful mood-altering drug that acts both as a stimulant and as s a relaxant. Within several second, the nicotine inhaled from a cigarette reaches the brain (that's twice as fast as IV cocaine and at least 50 times faster than a shot of alcohol) and exerts a powerful effect on its electrical and chemical activity."₁₅

The smaller particulate matter occurring in SHS is of particular concern. The smaller the particle size, the deeper it gets inhaled and settles in the lower respiratory tract, thereby increasing the dose response of the exposure by increasing the exposed surface area to SHS.₁₃ Many people breathe more SHS than they realize. Smokers are seriously endangering other as well as themselves. Recent studies indicate that everyone shows some evidence of SHS exposure, a consequence of "living in a society that still tolerates smoking in too many places."₃

METHOD

The risks estimated from SHS are based mostly on epidemiology, the branch of medicine that studies epidemics. This means that scientists examine patterns of illness among people rather than proving cause-and-effect in experiments.₁₆ It's obvious that the effects of SHS cannot be measured by purposely exposing people for decades to SHS and then checking for results. Scientists and educators have resorted to drawing conclusions based on consistencies appearing among various epidemiological studies. Unfortunately this is probably about as good as the human evidence on SHS is likely to get.₄ Although these types of studies lack the 'cause-and-effect' formal scientific approach, the statistics derived from this approach still manage to prove that SHS should be taken seriously.

EFFECT OF SHS ON THE LUNG

When secondhand smoke enters the air and its dirty cloud is inhaled, the same thing happens in a nonsmoker's body that takes place in the body of a smoker. "The nicotine and cancer causing tars deposited in your mouth, throat and lungs. Your blood picks up the poisons from your lungs and transports them throughout your body."₁₀

The fact that active cigarette smoking is the main cause of lung cancer in smokers is old news. Vital statistics provide a reality check when the frequency of nonsmokers acquiring lung cancer is increasing. Over a dozen epidemiological studies have found a correlation between exposure to smoke and an increased risk of lung cancer in nonsmokers. "Women married to smokers are considered the high risk 'exposed' group, and are compared with 'unexposed' wives of nonsmokers. The spouse of smokers have about 30% greater risk of getting lung cancer according to the National Academy of Sciences report."₁₇

Though lung cancer is rarely viewed as a women's issue, it has recently surpassed breast cancer as the leading cancer killer of women.3 Lung cancer is more likely to cause death than breast cancer with "only 13 out of 100 people surviving more than 5 years after being diagnosed."₂₀ The effects of passive smoking in persons who had never smoked or used any tobacco product was investigated through a multicenter, population-based, case control study. Investigators analysed data from 653 women with histologically confirmed lung cancer and 1,253 randomly selected female controls. They concluded that passive smoking significantly increased the risk of lung cancer (pulmonary adencarcinoma of the lung as well as cancers of other histopathological cell types). There is a significant association with lung cancer and exposure to SHS in the home, workplace, and social settings.

EFFECTS THAT SHS HAS ON THE HEART

Nonsmokers are more adversely affected by SHS than smokers for various reasons. Nonsmokers are more vulnerable to injury from SHS because their cardiovascular systems are not immune to the toxic fumes that are being inhaled. "Regular smokers are chronically and continually adversely effecting their cardiovascular systems which in turn, adapt to compensate for all of the harmful effects. Nonsmokers do not have the benefit of this adaptation, which offers some protection."₇ Exposure to specific elements of SHS cause blood to clot more easily and damages arterial linings - two critical steps in the development of heart disease.4 Short term exposure to secondhand smoke damages the heart. It causes problems between the heart and blood system. Carbon monoxide's affinity for hemoglobin is 250 times greater than oxygen. When carbon monoxide is inhaled in SHS it displaces the oxygen from the hemoglobin molecule forming a very strong bond. The blood cells will carry the carbon monoxide from the smoke to all the other cells in the body, therefore reducing the supply of oxygen increases platelet sensitivity and makes some blood cells stickier, increasing the likelihood of blood clots that cause heart attacks.₁₆ Long term exposure to SHS increases plaque buildup, those fatty deposits in arteries that promote heart disease, and has adverse effects on blood cholesterol which could cause serious problems for someone with coronary artery disease.₁₈

By pooling and analyzing the results of 11 recent studies, Stanton Glantz, a heart researcher at the University of California, showed that living with a smoker has roughly the same effect on heart disease mortality that it has on lung cancer mortality. "The risk for acquiring both lung cancer and heart disease rise by about 30% in the nonsmoker."₁₉ Glantz also fingered SHS as "the cause of 33,700 fatal cases of heart disease each year, further confirming SHS to be the third leading cause of preventable death from disease (smoking is first, alcohol is second)."₃ Glantz further goes on to say that "heart disease is 10 times as preventable as lung cancer, the same risk factor of 30% yields 30,000 - 40,000 annual deaths. Combining that toll with 3,000 - 4,000 lung cancer deaths, and factoring in an estimated 10,000 deaths from nonlung cancers caused by passive smoking, Glantz gets a grand total of about 5,000 deaths. In short, one nonsmoker dies for every eight smokers."₁₉

Another study supporting the risks of SHS at the workplace was done by Michael Sielgel from the Centers for Disease Control. He found the "nonsmokers who work in smoky bars and restaurants also have a 50% greater chance of developing lung cancer. A nonsmoking waiter who worked in a smoky bar for 5 years recently won a $95,000 settlement after getting sick with heart disease initiated by the continuous exposure to SHS and its carcinogens.

EFFECTS OF SHS ON THE FETUS, INFANTS AND CHILDREN

When nonsmoking children, infants and fetuses are exposed to tobacco smoke they become passive smokers. They are involuntarily put at risk.

Even though the fetus is inside the mother's womb, it is not spared the effects of SHS. Harmful effects of SHS are transferred from the mother's lungs into the blood and across the placenta. "Eighty percent of women who smoke don't give up the habit when pregnant even though most know that smoking reduces birthweights, increases miscarriages and increases infant mortality, says John Robbins, M.D., chief of general medicine at the University of California Davis Medical Center."₃

The effects of SHS are intensified in children as opposed to adults. A small exposure to SHS can have a lot of impact on the future health of an unborn child. Nicotine emitted from SHS constricts the umbilical vein, restricting the flow of oxygenated blood from the mother to the fetus. Researchers believe that the resulting oxygen depravation, fetal hypoxia, may explain the increased incidence of miscarriage and stillbirth among smoking women.₁₅ As well, fetal hypoxia may contribute to a higher prevalence of fetal growth retardation, prematurity and low birthweights among children.10 Nicotine also "accelerates the heartbeat of the fetus, slows down respiratory movements, can be responsible for hemorrhaging, spontaneous abortions and increased death rates in the first few months after birth/"₁₄

Michale Lebowitz, professor of medicine at the University of Arizona and a member of the EPA panel that studies SHS, is convinced that "the combination of fetal hypoxia, prematurity and smaller than average size and weight (less than 5.5 pounds) may also conspire to retard physical and mental developments after birth."₁₅

Infants whose mothers smoke are "2 - 3 times more likely to die of sudden infant death syndrome (SIDS)", reports the Surgeon General's office.₁₅

SIDS is a major cause of death in infants between the ages of one month to one year. It is "the unexpected and sudden death of an apparently normal and healthy infant that occurs during sleep and with no physical or autopsic evidence of disease."₂₀ SIDS is seen most common in infants born prematurely and to those born to women who smoke.

The Surgeon General's office also estimates that "700 SIDS deaths each year are brought on by lung problems caused by SHS."₁₅

Smoke, and your children suffer. Acute respiratory illness (bronchitis, pneumonia and asthma), chronic middle-ear disease and lung cancer are all health risks posed on children from the exposure to noxious chemicals in SHS.

"Fifty to sixty-seven percent of children under 5 years of age live in homes with at least one adult smoker, and an estimated 9 million children breathe SHS regularly, usually at home."₇ Young children are most susceptible to all sorts of illnesses because they have "smaller airways, breathe more rapidly, and have more lung area per body than adults," explains John F. Banzhaf IV, executive director of Action on Smoking and Health, a national organization.₁₁

Analyzing data from a "national survey of 4,331 children, Boston City Hospital researchers found that children born to women who smoked more than half a pack of cigarettes a day during pregnancy were twice as likely to develop asthma."₂ Drawing on 50 recent studies, a new EPA report concludes that passive smoking not only "aggravated up to one million existing cases of childhood asthma each year, but causes 8,000 - 26,000 new cases."₆ Mark Witten, Ph.D., of the University of Arizona, exposed rabbits to burning cigarettes 15 minutes per day for 20m days - about the amount breathed by kids of smoking parents. Cells in rabbits' airways degenerated. It resembled an asthmatic reaction.₃ In children who have asthma, their bronchial tubes are very responsive to SHS. The airwaves become inflamed and obstructed, producing symptoms of shortness of breath, wheezing and coughing. Exposure to SHS can increase the frequency of these asthmatic attacks.

SHS irritates the eustachian tubes, the narrow channels that connect the ear and the throat. When that happen, the tubes can become swollen and blocked, fluid can build up in the tubes and become infected. Middle-ear effusions are a leading cause of childhood hearing loss.₂₂

CONCLUSION

The issue of tobacco consumption and the resulting exposure to indirect smoke is a very complicated issue. Ongoing research continues to support the strong correlation between involuntary inhalation of SHS and the increasing prevalence of health problems in healthy nonsmokers. Education has been the first step towards teaching the public about the serious consequences that occur with inhalation of the toxic fumes in SHS. Lung cancer, heart disease and the ill effects towards children can no longer be ignored. Control of SHS, and improvement of indoor air quality can only be achieved through reduction or elimination of cigarette smoking.

[abstract] [introduction] [mainstream vs sidestream smoke] [components of SHS] [method]
[effects of SHS on the lungs] [effects of SHS on the heart]
[effects of SHS on the fetus, infants and children]

[abstract] [introduction] [mainstream vs sidestream smoke] [components of SHS] [method]
[effects of SHS on the lungs] [effects of SHS on the heart]
[effects of SHS on the fetus, infants and children]

© 1997 Respiratory Therapy Society of Ontario (RTSO)