A Case-Control Study of Chronic Myelomonocytic Leukemia (CMML) in Shanghai, China: Evaluation of Risk Factors for CMML, With Special Focus on Benzene

ABSTRACT

The authors report the results of a hospital-based case-control study of all patients diagnosed with chronic myelomonocytic leukemia (CMML) (n = 36) from 28 participating hospitals over a 4-year period. Diagnoses were made by a single laboratory using 2001 World Health Organization (WHO) criteria. Subjects were matched to 2 control patients and interviewed concerning previous diseases, work histories, and exposures to potential etiologic agents. Peripheral blood and bone marrow findings revealed clinical features of both myelodysplastic syndromes (MDSs) and myeloproliferative neoplasms (MPNs), consistent with hematopoietic disease category of MDS/MPN. The frequency of clonal cytogenetic abnormalities in all CMML cases was 31%, with no consistent pattern identified. A select number of risk factors associated with occupational exposure, nonoccupational exposure, and prior medical or family history of disease were extracted from the questionnaire. The results were compared between the case and control subjects. A total of 5 study subjects (2 CMML cases and 3 control subjects) were determined to have had some benzene exposure. In addition, none of the highlighted risk factors associated with nonoccupational exposure to etiologic agents was significantly different among the study subjects. These results do not support an increased risk for developing CMML associated with historical exposures to benzene.

KEYWORDS:

• benzene
• CMML
• MDS/MPN
• risk factors

Acknowledgments

The Benzene Health Consortium was the funding source for the Shanghai Health Study in the form of a research grant. The consortium consisted of petrochemical companies, including British Petroleum Amoco, Chevron Texaco, ExxonMobil, Conoco Philips, and Shell Chemical. The research grant was administered by the American Petroleum Institute.

The authors would like to extend their appreciation to Amber Banducci and Carrie Kahn for their technical assistance with the preparation of the manuscript, Allan Holsomback for database management, as well as A. Robert Schnatter, Thomas Armstrong, Yimei Zhou, and the exposure assessment expert panel (especially Youxin Liang, Chi Zhang, and Xipeng Jin) for their contributions to the exposure assessment. The authors would also like to thank the participating hospitals, including Huashan Hospital, Xinhua Hospital, Long March Hospital, Huang Pu Central District Hospital, Renji Hospital, Ruijin Hospital, Huadong Hospital, Jin An Central Hospital, No. 1 People's Hospital, No. 5 People's Hospital, No. 6 People's Hospital, No. 9 People's Hospital, Yang Pu Central Hospital, Zha Bei Central Hospital, Shu Guang Hospital, Chang Ning Central Hospital, Tong Ji Hospital, Shong Jin Central Hospital, Zhong Shan Hospital, Railway Hospital, Rong Hua Hospital, Changhai Hospital, Occupational Disease Hospital, Jiading Central Hospital, 455 Hospital, Shidong Hospital, No. 1 Baoshan Hospital, and Putuo Central Hospital.