Early Life Exposure To Multiple Metals, Nutrition, and Growth in Children - A Scoping Review

In utero and childhood exposure to toxic metals is associated with poor child growth, a predictor of adverse health outcomes. Most existing research focuses on exposure to single metals; the effects of metal mixtures largely remain understudied. Further, few studies consider how diet/nutrients interact with metal mixtures.

To synthesize research on the relationship between in utero and childhood metal mixture exposures, nutritional status-metal exposure interactions, and child anthropometric outcomes.

PubMed and Embase were used to search literature published in 2010-2023. Included studies consisted of at least two in utero or childhood toxic metal exposures and examined anthropometric parameters as their main outcomes. Included articles underwent full-text screenings. Information on exposures, findings, nutritional variables, and statistical methods was extracted.

After deduplication and title and abstract screening, 95 publications were included; 70 on prenatal growth and 25 on postnatal growth. Nutritional status/diet was assessed as an effect modifier in 4.3% studies on prenatal and 12% studies on postnatal growth. Birthweight (91.4%), and height and body mass index (64%) were common indicators of prenatal and postnatal growth, respectively. Finally, 41.4% of studies on prenatal and 20% on postnatal growth included statistical models that tested for mixture effects.

Although many studies included multiple metals, their mixture effects largely remain untested. Additionally, inclusion of nutritional status/dietary intakes in statistical models is rare, highlighting the need for further research.