Occupational exposure among females in Missouri—Printing industry
Low: ≤8 years
High: >8 years
NOTE: NA=not available; U-TCA=urinary metabolite of trichloroethylene.
a95% CI calculated by the committee with standard methods from the observed and expected numbers presented in the original study.
b99% confidence limits.
Epidemiologic Studies of Exposure to Organic Solvents and Bone Cancer
Blair and colleagues (1998) extended the followup of a cohort of aircraft-manufacturing workers (Spirtas et al., 1991) that used a detailed exposure-assessment method. An increased bone cancer risk was reported after adjustment for age, calendar time, and sex (RR=2.1, 95% CI =0.2–18.8) in workers exposed to trichloroethylene.
One study assessed whether an association existed between exposure to benzene and bone cancer. To evaluate the specific relationship between exposure to benzene and cancer risk, Wong (1987a) examined mortality among workers employed in seven chemical-manufacturing plants. An increased relative risk of bone cancer was found in the exposed group of workers (SMR=3.17, 95% CI=0.38–11.46). Wong (1987b) also estimated exposure to benzene in terms of 8-hour TWAs and peak levels of exposure and found that the relative risk of bone cancer increased with duration of exposure (SMR=6.63; one exposed case). Those results were inconclusive for an association because of the very small number of exposed cases, which resulted in highly variable risk estimates.
Fu and colleagues (1996) examined two historical cohorts of shoe workers in England and Florence, Italy, and used job titles to assess cancer mortality in relation to exposure to leather dusts and solvents. A slight increase in bone cancer was observed in the English cohort among those with probable solvent exposure (SMR=1.12, 95% CI=0.03–6.26), and no cases of bone cancer were reported in the Florence cohort. The committee reviewed the study by Nielsen and colleagues (1996) in which the risk of bone cancer in a cohort of lithographers was examined. Only one exposed case was observed (SIR=11.4, 95% CI=0.6–56.0).