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Table 1 (continued):
Reference
Emmelin et al.
1993 Sweden
Kaplan 1959
USA
Study Design,
Population, and
Exposures
Case-control
Exposure variable:
Machine time
high*
Fuel consumption
high*
Exposed time
high*
Exposure &
Smoking:
Machine time
medium
high
smoker
Fuel consumption
medium
high
smoker
Exposed time
medium
high
smoker
Cohort
Total
Most likely
exposed
Epidemiological Studies of Exposure to Diesel Exhaust and Lung Cancer Studies
Among Transport (i.e. bus) and Equipment Workers
Cases
or
deaths
14
15
19
154
49
Effect
Measure
OR
1.3
1.7
2.9
1.8
2.9
5.7
1.5
2.9
5.5
2.7
6.8
6.2
SMR
0.80
0.875
Confidence
Interval a or
P-Value
0.3-5.6**
0.5-5.9**
0.8-10.7**
0.5-6.6**
0.6-14.4**
2.4-13.3**
0.5-4.8**
0.7-11.5**
2.4-12.7**
0.6-11.3**
1.3-34.9**
2.6-14.6**
0.68-0.94
N.S.
Comments
Study was a nested case-control of lung cancer
among Swedish male dockworkers in the cohort
studied by Gustafsson et al. (1986). 154 referents
were matched to 50 cases on port and date of birth.
Indices of exposure to diesel exposure were derived
from employment records and records of annual fuel
consumption by diesel vehicles. Three different
exposure classifications were created: “machine
time”, “fuel consumption” and “exposed time”.
Information on smoking was obtained from
questionnaires and interviews with foremen or
workers who had worked with subjects. Response
rate for mailed questionnaires was low (67%) but
information from the interviews was available for
95% of the subjects. Some ex-smokers were
classified as never smokers. No exposure level
(“low”, “medium”, or “high”) was significant for
any DE exposure scheme (only “high” strata
reported here). Comparisons based on exposure and
smoking tended to find more elevated risks.
Investigators noted that the increase in the OR for
both smoking and exhaust exposure indicate that
smoking does not explain the results from the
exposure-only models, and that there may be an
interaction between smoking and exhaust exposure.
No information on asbestos exposure, which was
said to have decreased by the 1970s. See also
Gustafsson et al. (1986).
* “Low” exposure category used for reference
comparison.
**Note: authors reported confidence intervals at
90% level.
Cohort consisted of 6,506 deaths among railroad
workers from the Baltimore and Ohio Railroad Relief
Department between 1953 and 1958.
Subjects were categorized into 3 groups by exposed
to diesel exhaust and compared with national lung
cancer mortality rates. IARC noted that since
the changeover to diesel engines began in 1935 and
was 95% completed by 1959 (Garshick et al. 1988),
few, if any, of the lung cancer deaths could have
occurred in workers with more than 10 years of
exposure to diesel exhaust. No data on smoking.
a 95% Confidence intervals unless noted. N.S.= Not significant. No confidence intervals or p-values
reported in original study. DE = Diesel Exhaust, OR = Odds Ratio, RR = Relative Risk, SIR =
Standardized Incidence Ratio, SMR = Standardized Mortality Ratio
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