Effects of single and mixed metal exposure on neurocognitive health and quality of life among adults from Bihar India

Cognitive decline due to environmental exposure to metals and metalloids is a global public health concern because of their potential neurotoxic effects. While individual metal exposures have been linked to cognitive impairment, the effects of simultaneous and combined exposures remain inconclusive. This cross-sectional study was conducted among the adults residing in Bihar state to evaluate the burden of beryllium (Be), vanadium (V), chromium (Cr), cobalt (Co), arsenic (As), selenium (Se), strontium (Sr), silver (Ag), cadmium (Cd), caesium (Cs), barium (Ba), lead (Pb), and uranium (U) metals and their individual and mixed associations. Cognitive and quality of life scores were assessed using the MoCA and the WHO-QoL Brief questionnaire. The log-transformed metal and metalloid concentrations were inversely correlated with the cognitive scores (ρ -0.29 to -0.78) and HR-QoL scores (ρ > -0.5; P < 0.05). The cognitive scores were directly associated with the QoL domains (ρ > 0.5; P < 0.05). The metals As, V, Co, Se, Cs, and U had a strong negative influence on cognitive scores (β > -2.5; P < 0.05). The AENT model revealed As, Co, and Cr as the most influential metals on the cognitive score, where the combined effect of multiple metals and metalloids on cognitive impairment was (β = -5.75 (-6.68, -4.81) (P < 0.001). This highlights the individual and joint detrimental impacts of metals and metalloids on cognitive decline and poor HR-QoL, emphasising the need for clinical biomonitoring of metal exposure.