<p>Supplementary Table 2 presents the quality assessment of included studies using the Newcastle-Ottawa Quality Assessment Scale (NOS). The NOS is a standardized tool designed to evaluate the methodological quality of non-randomized studies, such as case-control and cohort studies, included in systematic reviews and meta-analyses. Each study is assessed across three domains: (1) selection of study groups, (2) comparability of groups, and (3) assessment of exposure and outcomes. Studies receive a star rating in each domain, with higher scores indicating higher methodological quality and lower risk of bias. This table summarizes the quality ratings for each included study, providing an overview of the strengths and limitations relevant to the interpretation of the meta-analysis findings.</p>
ARTICLE ABSTRACT
Benzene is a known cause of leukemia and other blood cancers, but its link to female genital cancers (ovarian, endometrial, and cervical) remains unclear. This meta-analysis evaluated the association between occupational benzene exposure and the risk of these cancers. A systematic search of PubMed, SCOPUS, and EMBASE identified 7,221 publications, with nine cohort studies meeting inclusion criteria. Summary risk ratios (RR) were calculated using Preferred Reporting Items for Systematic Reviews and Meta-Analyses; Meta-analysis of Observational Studies in Epidemiology; and Participants, Exposition, Comparators, Outcomes, and Study Design guidelines. Study quality was assessed with a modified Newcastle–Ottawa scale, and publication bias was evaluated via the Egger test and funnel plots. The overall summary RR for benzene exposure was 1.22 [95% confidence interval (CI), 1.03–1.44], primarily driven by mortality (RR = 1.69; 95% CI, 1.18–2.41) rather than incidence (RR = 1.08; 95% CI, 0.91–1.29). Cancer-specific RRs were 1.24 for cervical, 1.21 for endometrial, and 1.28 for ovarian cancers, none reaching statistical significance. No significant heterogeneity was found by cancer type, region, exposure duration, industry, or study quality. No publication bias was detected (P = 0.43). This analysis suggests a potential association between occupational benzene exposure and increased risk of female genital cancers, particularly in mortality data. However, the evidence remains inconclusive due to potential confounding factors and limitations in the available studies.
