RiskAnalysis 43Therefore, one cannot unequivocally relate any given individual lung cancer death
to cigarette smoking?
Risk may be expressed in several ways:
Deaths per 100,000 persons. In 1998, in the United States, 260,000 smokers
died as a result of lung cancer and chronic obstructive pulmonary disease (COPD),
according to the National Center for Health Statistucs. In that year, the United States
had a population of 270.3 million. The risk of death (from these two factors) associated
with habitual smoking may thus be expressed as deaths per 100,000 population, or
(260,000)(100,000)
270.3 x lo6= 96.
In other words, a habitual smoker in the United States has an annual risk of 96 in
100,000, or about one in a thousand, of dying of lung cancer or COPD. The probability
is 9.6 x the consequence is death from lung cancer or COPD. Table 3-1 presents
some typical statistics for the United States (National Center for Health Statistics,
2000).
Deaths per 1,OOO deaths. Using 1998 data again, there were 2,337,256 deaths in
the United States that year. Of these, 260,000, or 111 deaths per 1,000 deaths, were
related to habitual smoking.
Loss of years of life or for occupationul risks, loss of work days or work years.
Loss of years of life depends on life expectancy, which differs considerably from one
country to another. Average life expectancy in the United States is now 75 years; in
Canada, it is 76.3 years and in Ghana, 54 years (World Resources Institute, 1987).
Table 3-2 (from National Center for Health Statistics) gives the loss of life expectancy
from various causes of death in the United States.
These figures show that meaningful risk analyses can be conducted only with
very large populations. Health risk that is considerably lower than the risks cited in
Tables 3-1 and 3-2 may not be observed in small populations. Chapters 19 and 20 cite
several examples of statistically valid risks from air pollutants.
EXAMPLE 3.1. A butadiene plastics manufacturing plant is located in Beaverville, and
the atmosphere is contaminated by butadiene, a suspected carcinogen. The cancer
death rate in the community of 8000 residents is 36 people per year, and the total death
rate is 106 people per year. Does Beaverville appear to be a healthy place to live, or is
the cancer risk unusually high?
4Despite this principle of risk analysis, in 1990 the family of Rose Cipollino successfully sued cigarette
manufacturers and advertisers, claiming that Ms. Cipolliio had been enticed to smoke by advertising, and
that the cigarette manufacturers had concealed known adverse health effects. Ms. Cipollino died of lung
cancer at the age of 59.