Maternal Blood Manganese Levels and Infant Birth Weight

• Published in: Epidemiology (Cambridge, Mass.) Mass.), 2009-05, Vol.20 (3), p.367-373
• Main Authors: Zota, Ami R., Ettinger, Adrienne S., Bouchard, Maryse, Amarasiriwardena, Chitra J., Schwartz, Joel, Hu, Howard, Wright, Robert O.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Biological and medical sciences; Birth weight; Birth Weight - drug effects; Blood; Body mass index; Cross-Sectional Studies; Epidemiology; Female; Fetal Blood; General aspects; Gestational age; Hemoglobins; Humans; Infant, Newborn; Infants; Male; Manganese; Manganese - adverse effects; Manganese - blood; Maternal age; Medical sciences; Miscellaneous; Models, Statistical; Mothers; Oklahoma; Pregnancy; Public health. Hygiene; Public health. Hygiene-occupational medicine; Reproductive; Umbilical cord; Young Adult
• ISSN: 1044-3983; 1531-5487
• DOI: 10.1097/EDE.0b013e31819b93c0

Background: Manganese is both an essential element and a known neurotoxicant to children. High manganese exposures have been associated with negative reproductive outcomes in animals, but few epidemiologic studies have examined the effects of human fetal manganese exposure. Methods: We studied the association between maternal and umbilical cord blood manganese levels and birth weight in a cohort of 470 mother-infant pairs born at term (≥37 weeks gestation) in Ottawa County, Oklahoma. Nonlinear spline and quadratic regression models were used to test the hypothesis of an inverted U-shaped relationship between manganese levels and birth weight. Results: Mean (standard deviation) concentration of manganese was 2.4 (0.95) μg/dL in the maternal blood and 4.2 (1.6) μg/dL in the cord blood. Umbilical cord manganese was not associated with birth weight. A nonlinear relationship was observed between maternal manganese and birth weight after adjusting for potential confounders. Birth weight increased with manganese levels up to 3.1 μg/L, and then a slight reduction in weight was observed at higher levels. Compared with the 3.1-μg/L point of inflection, birth weight estimates at the 5th (1.3 μg/L) and 95th (4.0 μg/L) percentiles of exposure were - 160 g (95% confidence interval = -286 to -33) and -46 g (-38 to 131), respectively. Conclusions: Maternal blood manganese levels during pregnancy are associated with birth weight in a nonlinear pattern in full-term infants. These findings suggest that manganese may affect fetal growth. Possible detrimental effects of elevated manganese levels on the fetus should be further examined in more highly exposed populations.