<i>CoNaMad—Cohorte de Nacimiento de Madre de Dios</i> / Madre de Dios Birth Cohort to Study Effects of in-utero Trace Metals Exposure in the Southern Peruvian Amazon

Abstract

Background: In-utero exposure to mercury and other trace metals pose a significant threat to child health and development, but exposures and health impacts in artisanal and small-scale gold mining (ASGM) environments are poorly defined. Objectives:We describe the CONAMAD study design, a prospective birth cohort consisting of multiparous women (18 and over) living in rural and peri-urban Peruvian Amazon communities exposed to ASGM. Methods: Pregnant women are enrolled from health posts across four zones of Madre de Dios, Peru. Data are collected at enrollment, childbirth, and (planned) 36-48 months. At enrollment, hair samples for mercury assessment, demographic and clinical data are obtained. At birth, we obtain venous and cord blood, placenta, hair, toenails, and saliva. Findings: Two hundred seventy mothers were enrolled at an average 20 weeks gestational age with no differences in maternal characteristics across zones. Two hundred fifteen mothers were successfully followed at birth. We obtained 214 maternal and cord blood samples, 211 maternal and 212 infant hair samples, 212 placenta samples, 210 infant saliva samples, and 214 infant dried blood spots. Data collected will allow for testing our primary hypotheses of maternal malnutrition modifying ratios of cord:maternal blood total mercury (tHg), cord blood:maternal hair tHg, and infant:maternal hair tHg, and whether chemical mixtures (Hg, Pb, Cd) have synergistic effects on infant neurodevelopment.Conclusions: CONAMAD is designed to collect and store samples for future processing and hypothesis testing associated with in-utero mercury exposure and child development. We have completed the exposure assessments and will conduct a follow-up of mothers to evaluate early child development outcomes, including developmental delay and growth. These data offer insights into disease mechanisms, exposure prevention, and policy guidance for countries where ASGM is prevalent.

In Utero Exposure to Metals and Birth Outcomes in an Artisanal and Small-Scale Gold Mining Birth Cohort in Madre de Dios, Peru

“…Data were collected in 2017–2018 as part of the CONAMAD birth cohort based in Madre de Dios, Peru, and was approved by the institutional review board of Universidad Peruana Cayetano Heredia, SIDISI 66471. 51 The cohort is described in detail by Pan et al. 51 Madre de Dios is a hotspot of global biodiversity as well as global Hg pollution owing to the rapid expansion of artisanal and small-scale gold mining (ASGM) over the past two decades.…”

“… 51 The cohort is described in detail by Pan et al. 51 Madre de Dios is a hotspot of global biodiversity as well as global Hg pollution owing to the rapid expansion of artisanal and small-scale gold mining (ASGM) over the past two decades. CONAMAD is one of the few birth cohorts conducted in Latin America and the Caribbean that has collected prenatal exposure data and the only birth cohort of which we are aware that is based in an ASGM region.…”

“…Enrollment sites were in four zones differentiated by land use and presence of ASGM [Zone 1: ASGM region ( ), Zone 2: ASGM and agriculture ( ), Zone 3: Puerto Maldonado ( ), Zone 4: agriculture ( )], with no statistically significant differences in birth weight, gestational age, anemia, or hypertension by zone. 51 Inclusion criteria included multiparous women with at least one other child from the same biological father and a planned birth in Madre de Dios because the study was originally designed to evaluate the potential epigenetic effects from Hg exposure. Women were excluded if medically diagnosed with type II diabetes prior to pregnancy, were a current smoker, resided outside Madre de Dios for during pregnancy or were planning to give birth outside of Madre de Dios.…”

“…Data are from the COhorte de NAcimiento de MAdre de Dios (CONAMAD) in Madre de Dios, Peru ( Figure 1 ). 51 …”

Diet choices determine mercury exposure risks for people living in gold mining regions of Peru

“…Hg intakes above this value pose toxicity risks for sensitive populations. Particularly vulnerable groups include pregnant women, children under six years old, people with impaired renal function, and those with heightened immune responses to trace metals [48][49][50]. The MeHg PTWI remains under review and subject to debate.…”