Dataset Information

Benzene Exposure Response and Risk of Myeloid Neoplasms in Chinese Workers: A Multicenter Case-Cohort Study.

ABSTRACT:

Background

There is international consensus that benzene exposure is causally related to acute myeloid leukemia (AML), and more recent evidence of association with myelodysplastic syndromes (MDS). However, there are uncertainties about the exposure response, particularly risks by time since exposure and age at exposure.

Methods

In a case-cohort study in 110?631 Chinese workers followed up during 1972-1999 we evaluated combined MDS/AML (n?=?44) and chronic myeloid leukemia (n?=?18). We estimated benzene exposures using hierarchical modeling of occupational factors calibrated with historical routine measurements, and evaluated exposure response for cumulative exposure and average intensity using Cox regression; P values were two-sided.

Results

Increased MDS/AML risk with increasing cumulative exposure in our a priori defined time window (2 to <10?years) before the time at risk was suggested (Ptrend?=?08). For first exposure (within the 2 to <10-year window) before age 30 years, the exposure response was stronger (P?=?.004) with rate ratios of 1.12 (95% confidence interval [CI]?=?0.27 to 4.29), 5.58 (95% CI?=?1.65 to 19.68), and 4.50 (95% CI?=?1.22 to 16.68) for cumulative exposures of more than 0 to less than 40, 40 to less than 100, and at least 100?ppm-years, respectively, compared with no exposure. There was little evidence of exposure response after at least 10 years (Ptrend?=?.94), regardless of age at first exposure. Average intensity results were generally similar. The risk for chronic myeloid leukemia was increased in exposed vs unexposed workers, but appeared to increase and then decrease with increasing exposure.

Conclusion

For myeloid neoplasms, the strongest effects were apparent for MDS/AML arising within 10?years of benzene exposure and for first exposure in the 2 to less than 10-year window before age 30 years.

SUBMITTER: Linet MS

PROVIDER: S-EPMC6681472 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Benzene Exposure Response and Risk of Myeloid Neoplasms in Chinese Workers: A Multicenter Case-Cohort Study.

Linet Martha S MS Gilbert Ethel S ES Vermeulen Roel R Dores Graça M GM Yin Song-Nian SN Portengen Lutzen L Hayes Richard B RB Ji Bu-Tian BT Lan Qing Q Li Gui-Lan GL Rothman Nathaniel N

Journal of the National Cancer Institute 20190501 5

<h4>Background</h4>There is international consensus that benzene exposure is causally related to acute myeloid leukemia (AML), and more recent evidence of association with myelodysplastic syndromes (MDS). However, there are uncertainties about the exposure response, particularly risks by time since exposure and age at exposure.<h4>Methods</h4>In a case-cohort study in 110 631 Chinese workers followed up during 1972-1999 we evaluated combined MDS/AML (n = 44) and chronic myeloid leukemia (n = 18) ...[more]

PMID: 30520970

Similar Datasets

Project description:Main purpose To evaluate the feasibility of a measurement-based assessment of benzene exposure in case-control studies of paediatric cancer; Additional aims To identify the sources of exposure variability; to assess the performance of two benzene biomarkers; to verify the occurrence of participation bias; to check whether exposures to benzene and to 50 Hz magnetic fields were correlated, and might exert reciprocal confounding effects. Pilot case-control study of childhood leukaemia and exposure to benzene assessed by repeated seasonal weekly measurements in breathing zone air samples and outside the children's dwellings, with concurrent determinations of cotinine, t-t-muconic acid (MA) and sulfo-phenylmercapturic acid (S-PMA) in urine. 108 cases and 194 controls were eligible for inclusion. Full-participation was obtained from 46 cases and 60 controls, with low dropout rates before four repeats (11% and 17%); an additional 23 cases and 80 controls allowed the collection of outdoor air samples only. The average benzene concentration in personal and outdoor air samples was 3 μg/m(3) (SD 1.45) and 2.7 μg/m(3) (SD 1.41), respectively. Personal exposure was strongly influenced by outdoor benzene concentrations, higher in the cold seasons than in warm seasons, and not affected by gender, age, area of residence or caseness. Urinary excretion of S-PMA and personal benzene exposure were well correlated. Outdoor benzene levels were lower among participant controls compared with non-participants, but did not differ between participant and non-participant cases; the direction of the bias was found to depend on the cut-point chosen to distinguish exposed and unexposed. Exposures to benzene and extremely low-frequency magnetic fields were positively correlated. Repeated individual measurements are needed to account for the seasonal variability in benzene exposure, and they have the additional advantage of increasing the study power. Measurement-based assessment of benzene exposure in studies of childhood leukaemia appears feasible, although it is financially and logistically demanding.

Dataset Information

Benzene Exposure Response and Risk of Myeloid Neoplasms in Chinese Workers: A Multicenter Case-Cohort Study.

Background

Methods

Results

Conclusion

Publications

Benzene Exposure Response and Risk of Myeloid Neoplasms in Chinese Workers: A Multicenter Case-Cohort Study.

Similar Datasets

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