<![CDATA[Background: Oyster mushrooms (Pleurotus ostreatus) are widely cultivated and consumed in Indonesia, but heavy metal contamination poses severe human health risks, such as digestive and neurological disorders. Despite numerous individual studies on heavy metal exposure, a comprehensive quantitative synthesis of their relative health risks remains lacking. This meta-analysis aimed to evaluate the health risk potential of arsenic, lead, mercury, and cadmium contamination in oyster mushrooms and assess their pooled effect sizes. Subjects and Method: A systematic literature search was conducted across PubMed, Scopus, Web of Science, and Google Scholar using PRISMA guidelines and PICO criteria to identify eligible studies on heavy metal contamination in Pleurotus ostreatus. A total of 10 articles met the inclusion and exclusion criteria and were synthesized using RevMan 5.4 software. Pooled effect sizes (Standardized Mean Differences) were calculated using a random-effects model to account for study variability, and heterogeneity was evaluated using the I2 statistic along with funnel plot symmetry for publication bias. Results: The meta-analysis of 10 studies revealed that lead exposure had the strongest correlation with health risk (Effect Size = 2.37;95% CI: 1.85-3.04), representing a significantly higher risk compared to mercury (Effect Size = 1.53;95% CI: [-1.01, 4.08]), respectively. Moderate heterogeneity was observed across studies (I2= 93%-97%, p < 0.05), while a symmetrical funnel plot indicated minimal publication bias. Conclusion: This meta-analysis quantitatively confirms that lead, arsenic, and cadmium present the highest health risks among heavy metal contaminants in cultivated Pleurotus ostreatus, with lead demonstrating the strongest overall risk association. These quantified risk magnitudes highlight an urgent need for targeted, mandatory monitoring of lead, arsenic, and cadmium levels in mushroom cultivation to safeguard public health.]]>
