Environmental Tobacco Smoke and Smoking Cessation

DEFINITION AND HEALTH EFFECTS

Environmental tobacco smoke consists of "mainstream" smoke exhaled

by an active smoker, and "sidestream" smoke released from the smoldering

end of a cigarette, pipe or cigar. ETS contains more than 3,800 different

chemicals. ETS is qualitatively similar to mainstream smoke, but

contains higher quantities of certain toxins such as ammonia, formaldehyde,

and nitrosamines. It is the main source of particulate matter of less

than 2.5 microns, a size that reaches the lower airways.

In 1998, more than 47.2 million U.S. adults, 24% of the population,

were cigarette smokers (Centers for Disease Control and Prevention, 2000).

Forty-three percent of children aged 2 months to 11 years lived in a home

with a cigarette smoker (Pirkle, Flegal, Bernert, et al., 1996). Young children

may spend a significant amount of their time indoors, in their own

homes, relatives* homes, and child care settings, exposing them to ETS

and making them passive smokers.

EFFECTS ON ADULTS

Adults may be exposed to ETS through a tobacco-using spouse or housemate.

ETS has been classified as a group A human carcinogen, indicating

that there is sufficient scientific evidence supporting a causal relationship

between exposure to ETS and the development of cancer. The U.S.

Environmental Protection Agency has estimated that ETS is responsible

for approximately 3,000 lung cancer deaths per year in nonsmokers in the

United States. In addition, exposure to ETS has been linked with an

increased risk of developing myocardial infarction, reduced pulmonary

function, cough, headache, nasal congestion, and eye irritation.

EFFECTS ON CHILDREN

Children exposed to ETS through maternal smoking may show a number

of negative health effects (American Academy of Pediatrics, 1999) including

(1) Lower respiratory tract infections: These infants are 38% more

likely to be hospitalized for pneumonia in the first year of life than children

whose mothers do not smoke; when both parents smoke, the infants

are twice as likely to be hospitalized than children whose parents do not

smoke. (2) Middle ear effusions: Children of parents who smoke are more

likely to develop middle ear effusion and otitis media. (3) Asthma: These

children are more likely to develop asthma, and those with asthma may

have more severe symptoms and more frequent exacerbations. (4) Sudden

infant death syndrome (SIDS): A growing body of evidence links ETS

exposure to an increased incidence of SIDS, independent of gestational

age or birth weight.

Exposure to ETS before age 10 raises the risk of developing leukemia

and lymphoma in adulthood.