An evidence-based analysis of epidemiologic associations between lymphatic and hematopoietic cancers and occupational exposure to gasoline

Abstract

The presence of benzene in motor gasoline has been a health concern for potential increased risk of acute myelogenous leukemia and perhaps other lymphatic/hematopoietic cancers for approximately 40 years. Because of the widespread and increasing use of gasoline by consumers and the high exposure potential of occupational cohorts, a thorough understanding of this issue is important. The current study utilizes an evidence-based approach to examine whether or not the available epidemiologic studies demonstrate a strong and consistent association between occupational exposure to gasoline and lymphatic/hematopoietic cancers. Among 67 epidemiologic studies initially identified, 54 were ranked according to specific criteria relating to the relevance and robustness of each study for answering the research question. The 30 highest-ranked studies were sorted into three tiers of evidence and were analyzed for strength, specificity, consistency, temporality, dose-response trends and coherence. Meta statistics were also calculated for each general and specific lymphatic/hematopoietic cancer category with adequate data. The evidence-based analysis did not confirm any strong and consistent association between occupational exposure to gasoline and lymphatic/hematopoietic cancers based on the epidemiologic studies available to date. These epidemiologic findings, combined with the evidence showing relatively low occupational benzene vapor exposures associated with gasoline formulations during the last three decades, suggest that current motor gasoline formulations are not associated with increased lymphatic/hematopoietic cancer risks related to benzene.

Long-Term Effects of Chromatin Remodeling and DNA Damage in Stem Cells Induced by Environmental and Dietary Agents

“…Gasoline station attendants are exposed to benzene fumes, and this exposure has been thought to lead to higher rates of lymphatic and hematopoietic cancers. 121 In support of this, one study showed a 1.6% decrease in global DNA methylation in these workers, suggesting an epigenetic mechanism of benzene action and cancer. 122 …”

Benzene Exposure and MicroRNAs Expression: In Vitro, In Vivo and Human Findings

“…Benzene is a pervasive occupational and environmental contaminant that affects human health [1][2][3]. It is well established that exposure to benzene exposure can result in hematotoxic (including immunotoxic), genotoxic and carcinogenic (i.e., leukemogenic) effects [10][11][12]. Although its metabolism is well known, the pathogenetic mechanisms through which it exerts its toxic effect, in particular on bone marrow, are not yet well defined.…”

“…Benzene was identified as a Group 1 carcinogen and recognized by the Internationa Agency for Research on Cancer (IARC) as a human carcinogen [9], with evidence support ing its carcinogenicity (leukemia) in occupational and non-occupational settings. Its expo sure has been extensively studied and there is epidemiological and toxicological evidence showing that high exposure to benzene can lead to the development of acute myeloid leukemia (AML) and nonlymphocytic leukemia (ANLL), as well as myelodysplastic syn drome (MDS), in humans [10,11]. Furthermore, developmental, reproductive, respiratory immunological and metabolic effects have been also identified [12], although the mecha nisms of its toxicity are not entirely clear.…”

Assessment of genotoxicity biomarkers in gasoline station attendants due to occupational exposure

“…According to the IARC classification, benzene is a group 1 human carcinogen, causing hematological changes such as leukocytosis and lymphopenia (Giardini et al, 2023). Benzene exposure remains the main focus of public health and occupational protection measures for gasoline (Keenan et al, 2013). Although the aforementioned chemicals have been part of many toxicological studies on their own, the toxicity and risks of combined exposure to these multiple chemicals need to be evaluated in countries where there is no self-service.…”