There is no safe level of exposure to tobacco smoke. Smoking tobacco has been linked to cancers of the bladder, esophagus, cervix, kidney, larynx, lung, oral cavity, leukemia, pancreas and stomach. It impacts cardiovascular health promoting coronary heart disease, abdominal aortic aneurysm, atherosclerosis and stroke. It plays a major role in respiratory diseases such as COPD, acute respiratory illnesses including pneumonia, coughing, phlegm, wheezing, dyspnea and in poor asthma control. It reduces fertility in women. It increases the risk of poor outcomes related to wound healing and surgeries. It lowers bone density in post-menopausal women, increases the risk of hip fractures and cataracts.
Consider the effects of tobacco smoke on the lungs. It damages the biological processes and
- alters the structural and functional properties of the lung
- damages the airway and injures the alveoli
- increases bronchial hyperresponsiveness
- precipitates asthma exacerbations
- alters the protease-antiprotease balance
- initiates distinct molecular mechanisms that affect the nitric oxide concentration in the airways
- delays the speed of bacterial clearance
- increases immune-inflammatory markers
- affects antiviral response
- alters respiratory host defence
- causes airway epithelial goblet cell hyperplasia
- affects IgG levels hence increasing the prevalence of viral infections
- intensifies systemic inflammation
- alters airway epithelial cell gene expression
- irreparably and irreversibly changes 13 of 97 genes
Smoking increases the risk of pneumonia, Legionnaire’s disease, periodontal and meningococcal diseases.
Second Hand Smoke (SHS)
The Surgeon General’s report on involuntary smoking noted that 50,000 deaths a year are due to second hand smoke (SHS) and more than 126 million Americans are exposed to SHS. SHS is passive smoking and is classified as a Group A carcinogen. SHS is also called environmental tobacco smoke (ETS). More than 4000 chemicals have been identified in ETS/SHS of which 60 are described as carcinogens. A further six – including nicotine and carbon monoxide – are known to interfere with normal cell development.
SHS has a detrimental effect on health. It has greater toxicity than mainstream smoke. It
- reduces lung function in utero
- permanently impairs lung growth in children and adolescents
- accelerates age-related decline in lung function in adults
- is a risk factor for the onset of asthma
- increases the severity of symptoms of asthma
- is causally associated with additional exacerbations
- reduces the effect of asthma medications
- irritates the upper respiratory tract
- increases the risk of lower respiratory tract infections
- has a dose-dependent relationship with death from lung and all cancers, COPD, heart disease, circulatory and respiratory disease
- is considered a neurotoxin that is linked to cognitive defects
Exposure to SHS and tobacco toxins has been associated with cognitive defects in children with the highest levels of exposure connected to the lowest reading and mathematics scores.
The messages about smoking and SHS have been spread and hopefully heard. However, many assume that smoking outdoors or through open windows eliminates the dangers from SHS. A study of homes with pre-school children showed that smoking outdoors exclusively, helped but still showed up in lower cotinine (a marker for nicotine exposure) levels in the children’s urine. SHS exposure and its contaminants were 5 to 7 times higher in homes where smoking took place outdoors than in homes of non-smokers.
Low levels of tobacco smoke contain toxic compounds, including 250 poisonous gases. Among the dangerous constituents are ammonia, arsenic, butane, cadmium, carbon monoxide, chromium, hydrogen cyanide, lead, polonium-210 and toluene, to name a few.
The dangers of tobacco smoke is not limited to ETS. Non-smokers can be exposed to tobacco toxins by off-gassing from the smoker’s clothing and also from exhaled toxins minutes after a cigarette is extinguished. Studies have shown the association between smoking and high levels of tobacco toxins even when there is no one actively smoking. The toxins can be found in air, dust and on all surfaces. The volatile toxic compounds can “off-gas” in the following days, weeks and months. Any disturbance will result in a re-suspension and the amount of airborne particles will be at the level consistent with that 4 hours after smoking. This exposure to particles in the air; dust and deposited on household surfaces and later re-suspended is known as third hand smoke (THS). It can also be found in used cars in which someone smoked.
Indoor surfaces become hidden reservoirs of THS pollutants and toxins. They react with other compounds in the environment to form secondary pollutants. THS is particularly dangerous for infants and children who spend most of the time indoors on hands and knees, touching, tasting, putting fingers in their mouths, playing on floors and in contact with contaminated surfaces. Exposure to THS can be though inhalation, ingestion or dermal contact of household dust on all surfaces.
THS is difficult to eradicate. Studies have found that two months after smokers moved out, toxins could still be detected in dust and surfaces of apartments. The usual cleaning methods of increasing ventilation, wiping and vacuuming are not effective in reducing nicotine contaminants.
Winickoff and colleagues studied the health beliefs of adults with respect to THS. They found that
- 95.4% of nonsmokers versus 84.1% of smokers agreed that SHS harms the health of children
- 65.2% of nonsmokers versus 43.3% of smokers agreed that THS harms the health of children
- 88.4% of nonsmokers versus 26.7% of smokers forbade smoking in their homes and car
- the urine cotinine levels of children in homes with a no-smoking policy were 6 times lower than in homes without.
Another recent study found that THS was unknown in low-income communities.
Recent research has shown that THS becomes more harmful over time and that the cumulative effects become increasingly toxic. THS was found to be mutagenic with chronic exposure far worse than acute exposure. THS can cause significant genetic damage. As THS ages it transforms and reacts with the indoor pollutant nitrous acid to form tobacco-specific nitrosamines which are carcinogenic and which damage DNA.
Health professionals, aware of the dangers of SHS and THS should encourage smokers to quit through smoking cessation programs. A frank discussion of the dangers inherent in smoking should clearly show that there is no future in smoking, not for them or for their families. There is no good news when it comes to tobacco ¾ first, second or third hand smoke.
US Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Washington, DC: US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006.
Piccardo MT, Stella A, Valerio F. Is the smokers exposure to environmental tobacco smoke negligible? Environ Health. 2010 Jan 29;9:5.
Johansson A, Hermansson G, Ludvigsson J. How should parents protect their children from environmental tobacco-smoke exposure in the home? Pediatrics. 2004;113(4) Available at: www.pediatrics.org/cgi/content/full/113/4/e291.
Invernizzi G, Ruprecht A et al. Residual tobacco smoke: measurement of its washout time in the lung and of its contribution to environmental tobacco smoke. Tob Control. 2007;16(1):29–33.
Singer BC, Hodgson AT, Nazaroff WW. Gas-phase organics in environmental tobacco smoke: 2—exposure-relevant emission factors and indirect exposures from habitual smoking. Atmos Environ. 2003;37(39):5551–5561.
Matt GE, Quintana PJ, Hovell MF, et al. Households contaminated by environmental tobacco smoke: sources of infant exposures. Tob Control. 2004;13(1):29–37.
Becquemin MH, Bertholon JF et al. Third-hand smoking: indoor measurements of concentration and sizes of cigarette smoke particles after resuspension. Tob Control. 2010;19(4):347-8. doi: 10.1136/tc.2009.034694.
Yolton K, Dietrich K et al. Exposure to environmental tobacco smoke and cognitive abilities among U.S. children and adolescents. Environ Health Perspect. 2005;113(1):98–103.
Matt GE, Quintana PJE, Hovell, et al. Residual tobacco smoke pollution in used cars for sale: air, dust, and surfaces. Nicotine Tob Res 2008;10:1467–75.
Winickoff JP, Friebely J et al. Beliefs about health effects of “thirdhand” smoke and home smoking bans. Pediatrics 2009;123:e74–9
Escoffery C, Bundy L et al. Third-hand smoke as a potential intervention message for promoting smoke-free homes in low-income communities. Health Educ Res. 2013 Oct;28(5):923-30. doi: 10.1093/her/cyt056.
Hang B, Sarker A et al. Thirdhand smoke causes DNA damage in human cells. Mutagenesis, 2013; 28 (4): 381 DOI: 10.1093/mutage/get013