Associations of blood heavy metal levels with intraocular pressure

PurposeWhether or which blood heavy metal levels (BHMLs) influence elevating intraocular pressure (IOP) are unknown. We examined the relationship among blood lead, mercury, and cadmium levels, blood pressure (BP), and IOP and assessed whether BP mediates these BHMLs-IOP associations.MethodsWe analyzed data on 8371 adult (≥20 years) from the Korea National Health and Nutrition Examination Survey from 2008 to 2012. Mediation analysis was used to examine the contribution of BP to the BHMLs-IOP relationship.ResultsIOP and three BHMLs were significantly associated with systolic and diastolic BP. But IOP was associated with only blood lead and mercury levels. BP significantly mediated lead-IOP and mercury-IOP associations: BP accounted for 20.5% and 14.2% of the association with IOP. Blood lead and mercury levels were significantly associated with IOP.ConclusionsBP significantly mediates the effects of those blood lead and mercury levels on IOP outcome. Prospective studies are needed to further examine the causal pathway from BHMLs to IOP elevation.