Background: The association between benzene exposure and non-Hodgkin lymphoma (NHL)
has been the subject of debate as a result of inconsistent epidemiologic evidence. An IARC
working group evaluated benzene in 2009 and noted evidence for a positive association between
benzene exposure and NHL risk.
Objective: To evaluate the association between occupational benzene exposure and nonHodgkin
lymphoma (NHL) among 73,087 women enrolled in the prospective population-based
Shanghai Women’s Health Study.
Methods: Benzene exposure estimates were derived using a previously developed exposure
assessment framework that combined ordinal job-exposure matrix intensity ratings with
quantitative benzene exposure measurements from an inspection database of Shanghai factories
collected between 1954-2000. Associations between benzene exposure metrics and NHL (n =
102 cases) were assessed using Cox proportional hazard models, with study follow-up occurring
from December 1996 through December 2009.
Results: Women ever exposed to benzene had a significantly higher risk of NHL (Hazard Ratio
(HR): 1.87, 95% C.I.: 1.19, 2.96). Compared to unexposed women, significant trends in NHL
risk were observed for increasing years of benzene exposure (ptrend = 0.006) and increasing
cumulative exposure levels (ptrend = 0.005), with the highest duration and cumulative exposure
tertiles having a significantly higher association with NHL (HR: 2.07, 95% C.I.: 1.07, 4.01 and
HR: 2.16, 95% C.I.: 1.17, 3.98, respectively).
Conclusions: Our findings, using a population-based prospective cohort of women with diverse
occupational histories, provide additional evidence that occupational exposure to benzene is
associated with NHL risk.