Essential Indicators Identifying Chronic Inorganic Mercury Intoxication: Pooled Analysis across Multiple...

Area of Science:

• Environmental Health
• Occupational Medicine
• Toxicology

Background:

• Artisanal small-scale gold mining (ASGM) poses chronic health risks due to inorganic mercury vapor exposure.
• A rapid and reliable diagnostic tool for chronic inorganic mercury intoxication is essential for ASGM communities.
• This study aims to refine the existing diagnostic toolkit for mercury intoxication.

Purpose of the Study:

• To reduce the number of indicators used for diagnosing chronic inorganic mercury intoxication without compromising diagnostic accuracy.
• To perform a sensitivity analysis on established biomonitoring exposure limits for mercury.
• To compare biomonitoring limits with thresholds associated with mercury intoxication in ASGM.

Main Methods:

• Pooled cross-sectional health data from miners in Indonesia, Tanzania, and Zimbabwe were analyzed.
• Logistic regression and stepwise selection were used to identify key diagnostic indicators.
• Bayesian information criterion (BIC) and Cohen's kappa evaluated model performance and diagnostic agreement.
• Sensitivity analysis of mercury biomarkers (blood, hair, urine, urine/creatinine) was conducted using chi-square tests.

Main Results:

• Variable selection reduced the number of medical indicators from thirteen to ten, alongside biomarkers.
• A diagnostic model using ten medical indicators and four biomarkers achieved a Cohen's kappa of 0.87.
• Excluding blood mercury as a biomarker reduced diagnostic agreement (Cohen's kappa = 0.46).
• Optimal cut-points for biomarkers were determined: blood (11.6 μg/l), hair (3.84 μg/g), urine (24.4 μg/l), and urine/creatinine (4.26 μg/g).

Conclusions:

• A reduced set of ten indicators, along with key biomarkers, enables reliable diagnosis of chronic inorganic mercury intoxication.
• Simplifying diagnostic criteria can improve health assessments in ASGM settings.
• The study validates the effectiveness of a streamlined approach to diagnosing mercury poisoning in high-risk populations.