Study protocol: Lead exposure, diet, and cognitive development among school-age children in Guayaquil, Ecuador

Abstract Lead exposure is a major environmental health concern, especially in childhood, due to its neurotoxic effects even at low levels. This cross-sectional observational study aims to evaluate the association between lead accumulation in tooth enamel, cognitive performance, and dietary patterns in children aged 7 to 9 years belonging to the Archdiocesan Educational Network of Guayaquil, Ecuador. A total of 384 participants will be selected using stratified sampling according to socioeconomic status. Lead levels will be assessed using a validated dental enamel biopsy technique, while IQ will be measured using the Wechsler Intelligence Scale for Children – Fifth Edition (WISC-V). Dietary intake will be assessed using a Food Frequency Questionnaire (FFQ) validated for the Ecuadorian population. All procedures will ensure the safety, comfort, and confidentiality of participants. Potential risks, such as emotional distress or academic disruption, will be minimized through adapted protocols and ethical safeguards. This study seeks to provide critical local evidence on environmental lead exposure and its association with cognitive outcomes and dietary, to help inform future public health efforts.