Assessing causal relationships between lead exposure and non-cancerous health effects through the Bradford Hill Criteria.

Abstract

Background: Human exposure to lead can occur through many paths, including food. Food can be contaminated with lead by natural occurrence in soil and water, industrial pollution, food processing methods, and food packaging, preparation, and serving materials. Decades ago, lead exposure was found to cause neurological effects, including cognitive impairment in children. Since then, these neurological effects have driven lead regulations; however, lead may also play a causal role in other diseases.

Scope and approach: This study utilized the Bradford Hill Criteria with a 5-point scale to evaluate causality between dietary lead exposure and particular health risks: cardiovascular disease, reproductive effects, neurodevelopmental effects, and renal effects.

Findings and conclusions: Each health effect, respectively, received scores of 25 (cardiovascular), 24 (reproductive), 28 (neurodevelopmental), and 25 (renal), out of a maximum possible score of 32; for strength of evidence in association with lead exposure. The numbers themselves are only meaningful in the sense that they highlight that lead may cause multiple human health risks, not just neurological effects that have been the focus of policymaking worldwide. This study contributes by providing a structured evidence-based causal assessment of non-cancer health outcomes from dietary lead exposure. It advances the methodological rigor of structured causal assessments, emphasizes the need for research in targeted areas, informs regulatory decision-making, and guides future public health policy development.