Benzene exposure and hematopoietic mortality: A long-term epidemiologic risk assessment.
BACKGROUND
Previous studies of a cohort of rubber hydrochloride workers indicated an association between benzene exposure and excess mortality from leukemia and multiple myeloma. To determine whether risks remain elevated with increasing time since plant shutdown, we extended follow-up from 1981 through 1996.


METHODS
We evaluated risk using standardized mortality ratios (SMR) and generalized Cox proportional hazards regression models.


RESULTS
Five new leukemia cases were observed in benzene-exposed white males, but the summary SMR for this group declined from 3.37 (95% CI = 1.54-6.41) to 2.56 (95% CI = 1.43-4.22). In regression models, cumulative exposure was significantly associated with elevated relative risks for leukemia mortality. Four new multiple myeloma deaths occurred, three of which were in workers judged to be unexposed.


CONCLUSIONS
These findings reaffirm the leukemogenic effects of benzene exposure and suggest that excess risk diminishes with time.
Rinsky
R A
RA
Division of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226, USA.
Hornung
R W
RW
Silver
S R
SR
Tseng
C Y
CY
D000368:Aged; D001554:Benzene / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007938:Leukemia / Q000139:chemically induced* / Q000401:mortality; D015993:Life Tables; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000139:chemically induced* / Q000401:mortality; D009314:National Institute for Occupational Safety and Health, U.S.; D009784:Occupational Diseases / Q000139:chemically induced* / Q000401:mortality; D016016:Proportional Hazards Models; D018570:Risk Assessment; D014481:United States / Q000453:epidemiology
D001554:Benzene