Manganese, Monoamine Metabolite Levels at Birth, and Child Psychomotor Development

• Published in: Neurotoxicology (Park Forest South) Vol. 24; no. 4; pp. 667 - 674
• Main Authors: Takser, Larissa, Mergler, Donna, Hellier, Georgette, Sahuquillo, Josiane, Huel, Guy
• Format: Journal Article
• Language: English
• Published: Orlando, FL Elsevier B.V 01.08.2003; Elsevier
• Subjects: Adult; Biogenic Monoamines - blood; Biological and medical sciences; Chemical and industrial products toxicology. Toxic occupational diseases; Chi-Square Distribution; Child; Child, Preschool; Dopamine; Female; Fetal Blood - drug effects; Fetal Blood - metabolism; Follow-Up Studies; Humans; Infant; Infant, Newborn; Male; Manganese; Manganese - blood; Manganese - pharmacology; Medical sciences; Metals and various inorganic compounds; Neuropsychological Tests - statistics & numerical data; Pregnancy; Prenatal Exposure Delayed Effects; Prospective Studies; Psychomotor development; Psychomotor Disorders - blood; Psychomotor Disorders - chemically induced; Psychomotor Performance - physiology; Regression Analysis; Serotonin; Statistics, Nonparametric; Toxicology; Psychomotor development; Dopamine; Serotonin; Manganese; Pregnancy; Human; Progeny; Toxicity; Low dose; Child; Heavy metal
• ISSN: 0161-813X; 1872-9711
• DOI: 10.1016/S0161-813X(03)00058-5

Several studies have demonstrated neurobehavioral impairment related to manganese (Mn) exposure in the workplace. Exposure to high doses of manganese is associated with irreversible neurodegenerative disorders resembling idiopathic Parkinson disease. Although there is a risk of Mn accumulation in the foetus during pregnancy, little information exists about developmental effects of environmental low-level exposure in human. For this reason, we conducted a prospective epidemiological study in 247 healthy pregnant women and their babies to determine the long-term effect of in utero Mn levels on child’s psychomotor development. Concurrently, we examined the relationship between Mn tissue levels at delivery and foetal plasma monoamine metabolites. Of the newborns, 195 were examined at 9 months, 126 at 3 years and 100 at 6 years. At 9 months, the Brunet–Lézine scales were administered. The McCarthy scales of children’s abilities were used at 3 and 6 years. After adjustment for potential confounding co-factors (child’s gender, mother’s educational level), negative relationships were observed between cord blood Mn levels and several psychomotor sub-scales at age of 3 years: “attention” (partial r=−0.33, P<0.001), “non-verbal memory” (partial r=−0.28, P<0.01), and “hand skills” (partial r=−0.22, P<0.05). No significant relationships were observed between Mn measures at birth and the general psychomotor indices, Brunet–Lézine developmental quotient (DQ) at 9 months or McCarthy general cognitive index (GCI) at 3 and 6 years. Maternal blood Mn levels were negatively associated with foetal plasma HVA and 5-HIAA concentrations (adjusted for labour duration, child’s gender, and smoking during pregnancy), but the adjustment for monoamine levels at birth did not change the association between the Mn levels and the psychomotor scores. These results suggest that environmental Mn exposure in utero could affect early psychomotor development.