Intellectual Impairment in School-Age Children Exposed to Manganese from Drinking Water

• Published in: Environmental health perspectives 2011-01, Vol.119 (1), p.138-143
• Main Authors: Bouchard, Maryse F., Sauvé, Sébastien, Barbeau, Benoit, Legrand, Melissa, Brodeur, Marie-Ève, Bouffard, Thérèse, Limoges, Elyse, Bellinger, David C., Mergler, Donna
• Format: Article
• Language: English
• Subjects: Adolescent; Adult and adolescent clinical studies; Biological and medical sciences; Chemical and industrial products toxicology. Toxic occupational diseases; Child; Children; Children's Health; Cross-Sectional Studies; Diet - statistics & numerical data; Drinking water; Environment. Living conditions; Environmental Exposure - analysis; Environmental Exposure - statistics & numerical data; Female; Groundwater; Hair; Hair - metabolism; Health aspects; Humans; Intakes; Intellect; Intellectual deficiency; Intelligence; Intelligence - drug effects; Intelligence levels; Intelligence quotient; Male; Manganese; Manganese - analysis; Manganese - metabolism; Manganese - toxicity; Medical sciences; Metals and various inorganic compounds; Modeling; Potable water; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Public health. Hygiene; Public health. Hygiene-occupational medicine; School age children; Students - statistics & numerical data; Surveys and Questionnaires; Tap water; Toxicology; Water consumption; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity; Water Supply - analysis
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.1002321

Background: Manganese is an essential nutrient, but in excess it can be a potent neurotoxicant. Despite the common occurrence of manganese in groundwater, the risks associated with this source of exposure are largely unknown. Objectives: Our first aim was to assess the relations between exposure to manganese from drinking water and children's intelligence quotient (IQ). Second, we examined the relations between manganese exposures from water consumption and from the diet with children's hair manganese concentration. Methods: This cross-sectional study included 362 children 6—13 years of age living in communities supplied by groundwater. Manganese concentration was measured in home tap water (MnW) and children's hair (MnH). We estimated manganese intake from water ingestion and the diet using a food frequency questionnaire and assessed IQ with the Wechsler Abbreviated Scale of Intelligence. Results: The median MnW in children's home tap water was 34 µg/L (range, 1-2,700 µg/L). MnH increased with manganese intake from water consumption, but not with dietary manganese intake. Higher MnW and MnH were significantly associated with lower IQ scores. A 10-fold increase in MnW was associated with a decrease of 2.4 IQ points (95% confidence interval: — 3.9 to -0.9; p < 0.01), adjusting for maternal intelligence, family income, and other potential confounders. There was a 6.2-point difference in IQ between children in the lowest and highest MnW quintiles. MnW was more strongly associated with Performance IQ than Verbal IQ. Conclusions: The findings of this cross-sectional study suggest that exposure to manganese at levels common in groundwater is associated with intellectual impairment in children.