Health Assessment Document for Diesel Emissions - NSCEP | US ...

1 occupations). Analysis was conducted based on "usual occupation" on all study subjects, and
2 any occupation with sufficient cases was eligible for further analysis. In addition, cases enrolled
3 after 1985 for which there were self-reported diesel exhaust exposure and detailed work histories
4 were also analyzed separately.
5 Both matched and unmatched analyses were done by calculating the adjusted (for
6 smoking and education) relative odds using the Mantel-Haenzael method and calculating the test-
? based 95% confidence interval using the Miettinen method. Unconditional logistic regression
8 was used to adjust for potential confounders (the PROC LOGIST of SAS). Linear trends for risk
9 were also tested according to· Mantel.
1 0 Adjusted relative odds for possible and probable exposure groups as well as the truck
11 drivers were slightly below unity, none being statistically significant for the entire study·
12 population. Although slight excesses were observed for the self-reported diesel exhaust exposure
13 group and the subset of post-1985 enrollees for highest duration of exposure (for self-reported
14 exposure, occupations with probable exposure and for truck drivers), none was statistically
15 significant. Trend tests for the risk of lung cancer among self-reported diesel exhaust exposure,
16 · probable exposure, and truck drivers with increasing exposure (duration of exposure used as
17 surrogate for increasing dose) were nonsignificant too. Statistically significant lung cancer
18 excesses were observed for cigarette smoking only.
19 · The major strength of this study is availability of detailed smoking history. Even though
20 detailed information was obtained for the usual and five other occupations (1985), no effort was
21 made to estimate or verify the actual exposure to diesel exhaust; instead, duration of employment
22 was used as a surrogate for dose. The numbers of cases and controls were large; however, the
23 number of individuals exposed to diesel exhaust was relatively few, thus reducing the power of
24 the study. This study did not attempt latency analysis either. Given these limitations, the
25 findings of this study are unable to provide either positive or negative evidence for a causal
26 association between diesel exhaust and occurrence of lung cancer.
27
28 . 8.3.10. Emmelin et al. (1993): Diesel Exhaust Exposure and Smoking: A Case-Referent
29 Study of Lung Cancer Among Swedish Dock Workers
· 30 This is a case-control study of lung cancer drawn from the cohort defined as all-male
31 workers who had been employed as dock workers for at least 6 months between 1950 and 1974.
32 In the population of 6,573 froril20 ports, there were 90 lung cancer deaths (cases), identified
33 . through Swedish death and cancer registers, during the period of 1960 to 1982. Of these 90
34 deaths, the 54 who were workers at the 15 ports for which exposure surrogate information was
35 available were chosen for the cas_e-control study. Four controls, matched on port and age, were
211/98 8-36 DRAFT --DO NOT CITE OR QUOTE