Short Term Effects

Tobacco smoke is an allergen, and allergy sufferers can experience stuffy, runny noses, watery eyes, sneezing, coughing, wheezing, and all the other typical allergy symptoms within minutes of exposure. Some people with no known allergies and without asthma may cough in smoke-filled rooms, get headaches, feel nauseous, feel sleepy, and experience other ill effects. Many former smokers, and those who are trying to quit do not like to be around smoke as it can cause them to have cravings. Some people simply do not like the odor, which clings to hair and clothing.

Many of these short-term effects terminate after the exposure ends. Repeated exposure, however, is believed to cause more serious long-term effects.

Long Term Effects

• Increased risk of lung cancer
  • The effect of passive smoking on lung cancer has been extensively studied. Studies from the USA (1986US Department of Health and Human Services., The health consequences of involuntary smoking: report of the Surgeon General (DHHS Pub No (PHS) 87–8398), DHHS, Washington, DC (1986). PMID: 3097495, National Research Council., Environmental tobacco smoke: measuring exposures and assessing health effects, NRC, Washington, DC (1986)., 1992US Environmental Protection Agency., Respiratory health effects of passive smoking: lung cancer and other disorders, EPA, Washington, DC (1992)., 1997California Environmental Protection Agency., Health effects of exposure to environmental tobacco smoke, California EPA, Sacramento (1997). PMID: 9583639., 2001Centers for Disease Control and Prevention (CDC). State-specific prevalence of current cigarette smoking among adults, and policies and attitudes about secondhand smoke--United States, 2000. MMWR Morb Mortal Wkly Rep. 2001 Dec 14;50(49):1101-6. PMID: 11794619, 2003 Alberg AJ, Samet JM. Epidemiology of lung cancer. Chest. 2003 Jan;123(1 Suppl):21S-49S. PMID: 12527563 ), Europe (1998In: P Boffetta, A Agudo and W Ahrens et al., Editors, Multicenter case-control study of exposure to environmental tobacco smoke and lung cancer in Europe, J Natl Cancer Inst 90 (1998), pp. 1440–1450.), the UK (1998Scientific Committee on Tobacco and Health., Report of the Scientific Committee on Tobacco and Health, Department of Health, London (1998) ^*, Hackshaw AK. Lung cancer and passive smoking. Stat Methods Med Res. 1998 Jun;7(2):119-36. PMID: 9654638), and Australia (1997National Health and Medical Research Council., The health effects of passive smoking, Australian Government Publishing Service, Canberra (1997).) have consistently shown a significant increase in relative risk among those exposed to passive smoke.
• Increased risk of heart disease
• Increased risk of miscarriage and birth defects
• Increased risk of developing asthma, both for children and adults
• Learning difficulty in children
• Increased risk of lung infections
• Increased risk of ear infections
• Increased risk of allergies
• Worsening of asthma, allergies, and other conditions

Although the nature of passive smoking makes study design problematic, the weight of evidence from meta-analyses from around the world makes the dangers of passive smoking scientifically indisputable.

Epidemiological studies of passive smoking

In 1992, the Journal of the American Medical Association published a review of the evidence available from epidemiological and other studies regarding the relationship between secondhand smoke and heart disease and estimated that passive smoking was responsible for 35,000 to 40,000 deaths per year in the United States in the early 1980s. Some studies make the claim that non-smokers living with smokers have about a 25 per cent increase in risk of death from heart attack, are more likely to suffer a stroke, and can sometimes contract genital cancer. Some research, such as the Helena Study, suggests that risks to nonsmokers may be even greater than this estimate. The Helena Study claims that exposure to secondhand smoke increases the risk of heart disease among non-smokers by as much as 60 percent. Parents who smoke appear to be a risk factor for children and babies and are associated with low birth weight babies, sudden infant death syndrome (SIDS), bronchitis and pneumonia, and middle ear infections.

In 2002, a group of 29 experts from 12 countries convened by the Monographs Programme of the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) reviewed all significant published evidence related to tobacco smoking and cancer. It concluded:

These meta-analyses show that there is a statistically significant and consistent association between lung cancer risk in spouses of smokers and exposure to secondhand tobacco smoke from the spouse who smokes. The excess risk is of the order of 20% for women and 30% for men and remains after controlling for some potential sources of bias and confounding.

Additionally, studies assessing passive smoking without looking at the partners of smokers have found that high overall exposure to passive smoking is associated with greater risks than partner smoking and is widespread in non-smokers.

The National Asthma Council of Australia ^* cites studies showing that: Environmental tobacco smoke (ETS) is probably the most important indoor pollutant, especially around young children:

• Smoking by either parent, particularly by the mother, increases the risk of asthma in children.14,15,
• The outlook for early childhood asthma is less favourable in smoking households.15,
• Children with asthma who are exposed to smoking in the home generally have more severe disease.16,
• Many adults with asthma identify ETS as a trigger for their symptoms.17,

• Doctor-diagnosed asthma is more common among non-smoking adults exposed to ETS than those not exposed. Among people with asthma, higher ETS exposure is associated with a greater risk of severe attacks.18,

In France passive smoking has been shown to cause 3000 premature deaths per year.

Enstrom and Kabat

These studies have been criticised by the American Cancer Society, which describes the study as "misinformation", as both the original cohort and Enstrom and Kabat's spotty follow-ups, were entirely inappropriate for reliably determining ETS exposure, smoking history, etc. Furthermore, Enstrom and Kabat are funded by the tobacco industry. ASH published an analysis of the studies that concluded that the studies can not be trusted, as there appears to be a direct conflict of interest. Alongside other faults, this analysis also criticizes the BMJ for failing to inform readers who funded the studies.

Enstrom and Kabat have rejected this criticism, claiming that the American Cancer Society funded most of the first study, but pulled their funding at the last minute, forcing the researchers to look elsewhere to find funding. Further, they say were only able to find funding from a foundation funded by the tobacco companies. In response, ACS vice-president Michael Thun asserts that Enstrom had been funded by the tobacco industry since 1997 without informing the ACS, and that Enstrom had communicated with Philip Morris about the potential value of the CPS-I follow-up as early as 1990.

The study also attracted criticism for a number of methodological flaws:

• It did not account for participants' considerable ETS exposure before California implemented a smoking ban in the late 1990s
• The analysis did not account for losses to follow-up, nor misclassification
• The lower than usual relative risks for active smoking and coronary heart disease could have obscured the effect of ETS
• The participant group they used was designed to assess the effect of active smoking, not ETS

In addition, Enstrom and Kabat's work confirmed some harmful effects of secondhand smoke, in particular that it increased the risk of COPD.

Studies of passive smoking in animals

There is limited evidence in experimental animals for the carcinogenicity of mixtures of mainstream and sidestream tobacco smoke.

There is sufficient evidence in experimental animals for the carcinogenicity of sidestream smoke condensates.

A study conducted by the Tufts' School of Veterinary Medicine and the University of Massachusetts concluded that a cat living with a smoker is two times more likely to get feline lymphoma than one that is not. After five years living with a smoker, that rate increases to three times as likely. And, when there are two smokers in the home, the chances of getting feline lymphoma increases to four times as likely.

A study by Colorado State University found that a dog that has exposure to a smoker in the home is 1.6 times more likely to develop lung cancer than a dog that is not exposed to a smoker. The study also found that skull shape had an effect on the estimated risk of lung cancer in dogs.

Risk level of passive smoking

There is sufficient evidence that involuntary smoking (exposure to secondhand or 'environmental' tobacco smoke) causes lung cancer in humans.

Involuntary smoking (exposure to secondhand or 'environmental' tobacco smoke) is carcinogenic to humans (Group 1).

Most experts believe that moderate, occasional exposure to secondhand smoke presents a small, but measurable cancer risk to nonsmokers. The risk is considered more significant if non-smokers work in an environment where cigarette smoke is prevalent, although few studies bear this out.

In May 2006, the United States government's Center for Disease Control issued the first new study on secondhand smoke in 20 years. Surgeon General Richard Carmona summarized, "The health effects of secondhand smoke exposure are more pervasive than we previously thought. The scientific evidence is now indisputable: secondhand smoke is not a mere annoyance. It is a serious health hazard that can lead to disease and premature death in children and nonsmoking adults." The study estimated that living or working in a place where smoking is permitted increases the non-smokers' risk of developing heart disease by 25-30% and lung cancer by 20-30%. The study finds that passive smoke also causes sudden infant death syndrome (SIDS), respiratory problems, ear infections and asthma attacks in children.

Environmental Tobacco Smoke and Particulate Matter Emission

Controversy

Philip Morris, R.J. Reynolds and groups representing growers, distributors and marketers took legal action, claiming that the EPA manipulated scientific studies and ignored accepted scientific and statistical practices. In 1998 United States District Court Judge William Osteen, a former tobacco lobbyist vacated this study, declaring it null and void in a 92-page decision, that found that the EPA had manipulated results and violated scientific norms in order to achieve its pre-determined conclusion that passive smoke was harmful. Even though Osteen had worked as a lobbyist for the tobacco industry prior to becoming a judge, he has delivered rulings contrary to the interests of tobacco companies [http://www.highbeam.com/library/docfree.asp?DOCID=1G1:19396752&ctrlInfo=Round20%3AMode20c%3ADocG%3AResult&ao=.

Osteen's decision was overturned by the United States Court of Appeals for the Fourth Circuit in 2002 on the technical grounds that the report was not a reviewable agency action under the Administrative Procedure Act, and the EPA classification of tobacco was ultimately left intact. Because the substantive dispute was never resolved, the findings in Osteen's report are still used to argue that the issue of ETS is driven by politics rather than science.

Tobacco industry response

• Libertarian: the industry has sought to position the passive smoking debate as essentially concerned with civil liberties and smokers' "rights" rather than with health.
• Funding bias in research: in all reviews of the effects of passive smoking on health published between 1980 and 1995, the only factor associated with concluding that passive smoking is not harmful was whether an author was affiliated with the tobacco industry
• Delaying and discrediting legitimate research: Australia

Smoking bans

See also:Smoking bans

Countries (such as Ireland and Scotland) and jurisdictions (like New York State and Washington State) now prohibit smoking in public buildings as well as private businesses such as restaurants and clubs. The state of Florida bans smoking in all establishments whose income is primarily generated from the sale of food. Many office buildings contain specially ventilated smoking areas; some are required by law to provide them.

In addition, local governments, including cities and counties such as McLean County, Illinois, Marion County, Indiana, and Jackson County, Indiana are beginning to ban smoking in various places. The Marion County ban forbids smoking in nearly all places of employment ^*.

Many business owners protest such bans by arguing that smoking customers will go elsewhere, and that business at smoke-free workplaces will suffer. However, in 2006 a US surgeon general reviewSurgeon General, "The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General", 27 June 2006. of studies suggests that this may not be the case, and that business may actually improveRoesler, Richard. "Surgeon general: No safe level of secondhand smoke." CNN.com, Jun. 27, 2006..

Notes