Exposure to benzene at work and the risk of leukemia: a systematic review and meta-analysis

Abstract

BackgroundA substantial number of epidemiologic studies have provided estimates of the relation between exposure to benzene at work and the risk of leukemia, but the results have been heterogeneous. To bridge this gap in knowledge, we synthesized the existing epidemiologic evidence on the relation between occupational exposure to benzene and the risk of leukemia, including all types combined and the four main subgroups acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), and chronic myeloid leukemia (CML).MethodsA systematic literature review was carried out using two databases 'Medline' and 'Embase' from 1950 through to July 2009. We selected articles which provided information that can be used to estimate the relation between benzene exposure and cancer risk (effect size).ResultsIn total 15 studies were identified in the search, providing 16 effect estimates for the main analysis. The summary effect size for any leukemia from the fixed-effects model was 1.40 (95% CI, 1.23-1.57), but the study-specific estimates were strongly heterogeneous (I2 = 56.5%, Q stat = 34.47, p = 0.003). The random-effects model yielded a summary- effect size estimate of 1.72 (95% CI, 1.37-2.17). Effect estimates from 9 studies were based on cumulative exposures. In these studies the risk of leukemia increased with a dose-response pattern with a summary-effect estimate of 1.64 (95% CI, 1.13-2.39) for low (< 40 ppm-years), 1.90 (95% CI, 1.26-2.89) for medium (40-99.9 ppm-years), and 2.62 (95% CI, 1.57-4.39) for high exposure category (> 100 ppm-years). In a meta-regression, the trend was statistically significant (P = 0.015). Use of cumulative exposure eliminated heterogeneity. The risk of AML also increased from low (1.94, 95% CI, 0.95-3.95), medium (2.32, 95% CI, 0.91-5.94) to high exposure category (3.20, 95% CI, 1.09-9.45), but the trend was not statistically significant.ConclusionsOur study provides consistent evidence that exposure to benzene at work increases the risk of leukemia with a dose-response pattern. There was some evidence of an increased risk of AML and CLL. The meta-analysis indicated a lack of association between benzene exposure and the risk of CML.

Initial Diagnostic Workup of Acute Leukemia: Guideline From the College of American Pathologists and the American Society of Hematology

“…Benzene exposure, especially at high levels, is associated with an increased risk of AML. 84,85 Other exposures are more controversial. Embalmers and funeral-home workers exposed to formaldehyde are reported to have an increased mortality rate from AML, 86 but a more recent meta-analysis found no such increase in risk of leukemia for workers exposed to formaldehyde when results were adjusted for smoking history.…”

Benzene exposure from the BP refinery flaring incident alters hematological and hepatic functions among smoking subjects

“…Benzene exposure may affect the bone marrow leading to anemia and the development of cancer. Exposure to benzene may cause leukemia, lymphoma, multiple myeloma, aplastic anemia, and other solid cancers [2][3][4][5][6]. In addition, benzene exposure is associated with a wide range of non-cancerous but adverse effects including alterations in pulmonary, central nervous system, hematological, hepatic, and renal functions [7][8][9][10][11].…”

Cáncer relacionado con el trabajo en Brasil: descripción de las notificaciones, 2007-2012

“…En los trabajadores de la producción de bienes y servicios (II), el cáncer de las células del sangre fue observado en la tercera parte de este grupo, los cuales manejaban máquinas industriales. Los estudios apuntan mayor riesgo de leucemia entre trabajadores de la industria del caucho y, también, leucemia y mieloma múltiple en trabajadores de la industria petrolera expuestos al benceno 4,23 . En el presente estudio se observó un porcentaje considerable de trabajadores fumadores y ex-fumadores con diagnóstico de cáncer relacionado con el trabajo.…”