Research has
generated scientific evidence that secondhand smoke (that is, in
the case of cigarettes, a mixture of smoke released from the
smoldering end of the cigarette and smoke exhaled by the smoker)
causes the same problems as direct smoking, including heart
disease, cardiovascular disease, lung cancer, and lung ailments
such as COPD, bronchitis and asthma. Specifically, meta-analyses
have shown lifelong non-smokers with partners who smoke in the
home have a 20–30% greater risk of lung cancer, and those
exposed to cigarette smoke in the workplace have an increased
risk of 16–19%.
A wide array of negative effects are attributed, in whole or in
part, to frequent, long term exposure to second hand smoke. Some
of these effects include:
Cancer:
General: overall increased risk; reviewing the evidence
accumulated on a worldwide basis, the International Agency for
Research on Cancer concluded in 2002 that "Involuntary smoking
(exposure to secondhand or 'environmental' tobacco smoke) is
carcinogenic to humans (Group 1)."
Lung cancer: the effect of passive smoking on lung cancer
has been extensively studied. A series of studies from the USA
from 1986–2003, the UK in 1998, Australia in 1997 and
internationally in 2004 have consistently shown a significant
increase in relative risk among those exposed to passive smoke.
Breast cancer risk is increased by 70% in younger,
primarily premenopausal women. The California Environmental
Protection Agency has concluded that passive smoking causes
breast cancer and the US Surgeon General has concluded that the
evidence is "suggestive," one step below causal.
Passive smoking does not appear to be associated with
pancreatic cancer
Ear, nose, and throat: risk of ear infections
Circulatory system: risk of heart disease, reduced
heart rate variability, higher heart rate
Lung problems:
Risk of asthma
Pregnancy:
Risk of premature birth
General:
Worsening of asthma, allergies, and other conditions
Risk to children:
Risk of sudden infant death syndrome (SIDS)
Risk of developing asthma
Risk of lung infections
More severe illness with bronchiolitis, and worse outcome
Increased risk of developing tuberculosis if exposed to a
carrier
Risk of allergies
Risk of Crohn's disease
Risk of learning difficulties, although this may only be in
children exposed before birth. Animal models suggest a role for
nicotine and carbon monoxide in neurocognitive problems
Overall increased risk of death in both adults, where it is
estimated to kill 53,000 nonsmokers per year, making it the 3rd
leading cause of preventable death in the U.S. and in children.
Short-term
effects >>
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Second Hand Smoke Passive smoking
Long-term
effects
Short-term
effects
Causal
mechanisms
Epidemiological studies of passive smoking
1. Studies of passive smoking in animals
2.
Risk level of passive smoking
Current state of scientific opinion
1. Public
opinion
Controversy over harms of passive smoking
1. Critique of individual studies and epidemiology
2. World Health Organization controversy
3. EPA lawsuit
4. Tobacco-industry funding of research
Tobacco industry response
1. Position of major tobacco companies
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