Occupational Exposure to Benzene and Non-Hodgkin Lymphoma in a Population-Based Cohort: The Shanghai Women's Health Study.
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 International Agency for Research on Cancer (IARC) working group evaluated benzene in 2009 and noted evidence for a positive association between benzene exposure and NHL risk.


OBJECTIVE
We evaluated the association between occupational benzene exposure and 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 and 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% CI: 1.19, 2.96]. Compared with unexposed women, significant trends in NHL risk were observed for increasing years of benzene exposure (p(trend) = 0.006) and increasing cumulative exposure levels (p(trend) = 0.005), with the highest duration and cumulative exposure tertiles having a significantly higher association with NHL (HR = 2.07, 95% CI: 1.07, 4.01 and HR = 2.16, 95% CI: 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.
Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute (NCI), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Bethesda, Maryland, USA.
Bryan A
BA
Bassig
Melissa C
MC
Friesen
Roel
R
Vermeulen
Xiao-Ou
XO
Shu
Mark P
MP
Purdue
Patricia A
PA
Stewart
Yong-Bing
YB
Xiang
Wong-Ho
WH
Chow
Tongzhang
T
Zheng
Bu-Tian
BT
Ji
Gong
G
Yang
Martha S
MS
Linet
Wei
W
Hu
Heping
H
Zhang
Wei
W
Zheng
Yu-Tang
YT
Gao
Nathaniel
N
Rothman
Qing
Q
Lan
D000328:Adult; D000368:Aged; D001554:Benzene / Q000032:analysis*; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000139:chemically induced / Q000453:epidemiology*; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced / Q000453:epidemiology*; D016273:Occupational Exposure; D011446:Prospective Studies; D018570:Risk Assessment; D016387:Women's Health
D001554:Benzene