PD503 - MERCURY LEVELS IN PATIENTS WITH AUTOIMMUNE DISEASES: A SYSTEMATIC REVIEW

PD503

MERCURY LEVELS IN PATIENTS WITH AUTOIMMUNE DISEASES: A SYSTEMATIC REVIEW

Y. Huang^1,*, A. Forbes^1,2

¹Institute of Clinical Medicine, University of Tartu, ²Internal Medicine Clinic, Tartu University Hospital, Tartu, Estonia

Rationale: Dietary consumption of contaminated seafood is the major source of non-occupational mercury exposure in the general population. Chronic heavy metal accumulation poses a potential risk for autoimmune diseases.  This study compares mercury levels across blood, urine, and hair to clarify the association between mercury burden and autoimmune diseases.

Methods: We searched 15 multilingual databases. Both randomised and observational studies were included, which reported mercury levels in patients with autoimmune diseases and healthy controls. Two independent reviewers screened and assessed the eligibility. Data on study design, mercury levels, type of sample and diagnosis were extracted. Meta-analysis by StataNow/SE 19.5 used random-effects models to pool standardised mean differences of Hg concentration. The study protocol was registered on PROSPERO(CRD420251162652).

Results: Out of 2244 retrieved articles, 15 studies were included in the meta-analysis. For blood mercury, no significant differences were observed in either survey studies (SMD=0.02, 95%CI: -0.13 to 0.16, I²= 47.85%) or clinical case-based studies (SMD=0.51, 95% CI: -0.19 to 1.20, I²=95.91%), with results remaining robust in sensitivity analyses and disease subgroups. Urinary mercury levels were significantly higher in clinical patients (SMD = 0.55, 95% CI: 0.20 to 0.90, I²= 14.42%), whereas a survey study showed no significant difference (SMD = -0.16, P = 0.698). Additionally, two studies on hair mercury reported significantly higher mercury concentrations in patients with rheumatoid arthritis and systemic sclerosis, respectively.

Conclusion: The findings suggest that urinary and hair mercury levels, reflecting long-term exposure, are elevated in patients with autoimmune diseases. Blood mercury, indicating exposure within recent months, shows a weaker association. Chronic dietary mercury accumulation appears to be a potential risk factor for autoimmune diseases.

Disclosure of Interest: None declared