Associations among prenatal and postnatal arsenic, lead, and cadmium exposures and motor development in 3-year-old children: a longitudinal birth cohort study in Taiwan

Prenatal and postnatal exposures to heavy metals have been suggested to interfere with neurodevelopment, but the neurotoxicity of lead (Pb), arsenic (As), and cadmium (Cd) is still unclear. In this study, we aimed to assess the associations between the levels of As, Cd, and Pb and children’s neurodevelopment. A total of 299 mother–infant pairs were recruited in this study and their meconium were collected. After three years, 53 children underwent the Bayley Scales of Infant and Toddler Development (Bayley-III) examinations and provided hair and fingernail specimens. The levels of As, Cd, and Pb in the meconium, hair, and fingernail were measured by inductively coupled plasma mass spectrometry; the median levels were the following: meconium, 42.7, 5.57, and 25.6 ng/g, respectively; hair, 0.19, 0.05, and 3.61 μg/g, respectively; and fingernail, 0.29, 0.04, and 0.84 μg/g, respectively. After adjusting for potential confounding factors, we found that the log-transformed levels of As in the hair samples was negatively associated with gross motor development (β =  − 0.032; 95% confidence interval: − 0.061 to − 0.004). We conclude that postnatal exposure to As is a crucial period for gross motor development in children, while the effects of Cd and Pb on neurodevelopment are less clear.