Effect of environmental manganese exposure on verbal learning and memory in Mexican children

Torres-Agustín, R; Rodríguez-Agudelo, Yaneth; Schilmann, Astrid; Solís-Vivanco, Rodolfo; Montes, Sergio; Riojas-Rodríguez, Horacio; Cortez‐Lugo, Marlene; Rı́os, Camilo

doi:10.1016/j.envres.2012.10.007

Cited by 93 publications

(71 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These observations are also consistent with previous studies showing impairment associated with Mn exposure in immediate memory 54 and memory for histories and a word learning list. 30 …”

Section: Memorysupporting

confidence: 94%

Cognitive Effects of Manganese in Children and Adults

Lucchini¹,

Zoni²

2014

Manganese in Health and Disease

View full text Add to dashboard Cite

The interest in cognitive effects associated with manganese (Mn) exposure has constantly grown in the last 20 years. Mn is an essential element for humans, but concentrations even slightly exceeding the homeostatic range can affect cognition, especially in sensitive early life exposure windows. Exposure to Mn may impact adults and children differently, as based on different mechanisms. This chapter summarizes the main findings about the effect of manganese on specific cognitive domains, both in children and in adults, occupationally or environmentally exposed. A reduction of the intelligent quotient as a general cognitive deficit, and impairment of executive functions, memory, academic achievement, and mental development have been shown as a result of early life exposure to Mn. These outcomes are mainly related to high Mn content in drinking water but also to Mn airborne emission from ferroalloy and mining operations. New data on Mn exposure of pregnant mothers are also available as a result of the application of Mn-based fungicides. Adult studies have shown Mn-related effects on attention, memory, perceptual and motor speed, and visuospatial scanning abilities. The exposure route for adults is inhalation, from direct occupational exposure such as welding or caused by living in the vicinity of industrial emissions.

show abstract

“…These observations are also consistent with previous studies showing impairment associated with Mn exposure in immediate memory 54 and memory for histories and a word learning list. 30 …”

Section: Memorysupporting

confidence: 94%

Cognitive Effects of Manganese in Children and Adults

Lucchini¹,

Zoni²

2014

Manganese in Health and Disease

View full text Add to dashboard Cite

show abstract

“…At age 10.5 years, children’s verbal learning and memory abilities were assessed using either the English or Spanish version of the Children’s Auditory Verbal Learning Test, 2nd edition (CAVLT-2) (Talley 1997; Torres-Agustin et al 2013). We analyzed four subscales as continuous standardized scores (mean ± SD = 100 ± 15): Learning curve (learning progression), Immediate recall (susceptibility of new information to be disrupted), Delayed recall (long-term memory and retrieval ability), Immediate memory span (short-term memory), and Level of learning (long-term memory coding abilities) (Torres-Agustin et al 2013).…”

Section: Methodsmentioning

confidence: 99%

“…Postnatal Mn exposure has been associated with poor language development in toddler boys (Rink et al 2014), and behavioral problems in school-aged boys and girls (Ericson et al 2007). Studies of school-aged children and adolescents (6–14 year olds) have linked elevated Mn levels in drinking water, blood, and hair samples with oppositional behavior and hyperactivity (Bouchard et al 2007), impaired cognitive abilities (Bouchard et al 2011b; Kim et al 2009; Menezes-Filho et al 2011; Riojas-Rodriguez et al 2010; Wasserman et al 2006), and poor memory (He et al 1994; Torres-Agustin et al 2013), motor coordination (He et al 1994; Hernandez-Bonilla et al 2011; Lucchini et al 2012), and visuoperceptive speed (He et al 1994; Zhang et al 1995). To date, only one epidemiologic study has assessed exposure to Mn both prenatally and postnatally (Ericson et al 2007).…”

Section: Introduction1mentioning

confidence: 99%

Prenatal and postnatal manganese teeth levels and neurodevelopment at 7, 9, and 10.5years in the CHAMACOS cohort

Mora

Arora

Harley

et al. 2015

Environment International

View full text Add to dashboard Cite

Background Numerous cross-sectional studies of school-age children have observed that exposure to manganese (Mn) adversely affects neurodevelopment. However, few prospective studies have looked at the effects of both prenatal and postnatal Mn exposure on child neurodevelopment. Methods We measured Mn levels in prenatal and early postnatal dentine of shed teeth and examined their association with behavior, cognition, memory, and motor functioning in 248 children aged 7, 9, and/or 10.5 years living near agricultural fields treated with Mn-containing fungicides in California. We used generalized linear models and generalized additive models to test for linear and nonlinear associations, and generalized estimating equation models to assess longitudinal effects. Results We observed that higher prenatal and early postnatal Mn levels in dentine of deciduous teeth were adversely associated with behavioral outcomes, namely internalizing, externalizing, and hyperactivity problems, in boys and girls at 7 and 10.5 years. In contrast, higher Mn levels in prenatal and postnatal dentine were associated with better memory abilities at ages 9 and 10.5, and better cognitive and motor outcomes at ages 7 and 10.5 years, among boys only. Higher prenatal dentine Mn levels were also associated with poorer visuospatial memory outcomes at 9 years and worse cognitive scores at 7 and 10.5 years in children with higher prenatal lead levels (≥0.8 μg/dL). All these associations were linear and were consistent with findings from longitudinal analyses. Conclusions We observed that higher prenatal and early postnatal Mn levels measured in dentine of deciduous teeth, a novel biomarker that provides reliable information on the developmental timing of exposures to Mn, were associated with poorer behavioral outcomes in school-age boys and girls and better motor function, memory, and/or cognitive abilities in school-age boys. Additional research is needed to understand the inconsistencies in the neurodevelopmental findings across studies and the degree to which differences may be associated with different Mn exposure pathways and biomarkers.

show abstract

“…Mn was measured in blood (n=10), hair (n=7), or drinking water (n=1). Both hair and blood biomarkers were used in three studies, and all of these reported significant associations with neurodevelopmental outcomes for hair but not blood Mn [63, 65, 66]. …”

Section: Epidemiologic Evidence For Neurotoxic Effects Of Manganesementioning

confidence: 99%

“…Two cross-sectional studies in adolescents that measured blood Mn reported no significant association with IQ [55, 62], although one of these reported significant associations with deficits on the Learning Disability Evaluation scale (LDES) [55]. Another cross-sectional study found that hair Mn, but not blood Mn, was associated with long-term memory and learning on the Children’s Auditory Verbal Learning Test (CAVLT) among 7- to 11-year olds [66]. Despite a limited sample size (n=60), a cross-sectional study of 1- to 4-year old Uruguayan children reported significant inverse associations of hair Mn with cognition and language, especially among girls, but only in unadjusted models [64].…”

Section: Epidemiologic Evidence For Neurotoxic Effects Of Manganesementioning

confidence: 99%

Perinatal and Childhood Exposure to Cadmium, Manganese, and Metal Mixtures and Effects on Cognition and Behavior: A Review of Recent Literature

Sanders

Henn

Wright

2015

Curr Envir Health Rpt

236

134

View full text Add to dashboard Cite

Lead (Pb) and mercury (Hg) neurotoxicity is well established. In recent years, a growing body of evidence suggests that environmental exposure to other metals including arsenic (As), cadmium (Cd), manganese (Mn), and their mixtures also pose public health threats. In this paper we summarize the recent literature examining the relationship of prenatal and childhood environmental metal exposures with cognitive and behavioral outcomes in children. We conducted a literature search to identify epidemiologic studies that examined the relationship of Cd, Mn, and metal mixtures with children’s neurodevelopmental/cognitive and behavioral outcomes. We restricted the search to peer-reviewed studies published in English between January 2009 and March 2015. We identified a total of 31 articles of which 16, 17, and 16 studies examined the effects of Cd, Mn, or metal mixtures, respectively. Based on our review, there is suggestive evidence that prenatal/childhood Cd exposure may be associated with poorer cognition, but additional research is clearly needed. We found little evidence of behavioral effects of early life Cd exposure, and no studies found a significant relationship with attention deficit hyperactivity disorder. Studies of early life Mn exposure consistently reported negative impacts on both cognition and behavior. There is also growing evidence that co-exposure to multiple metals can result in increased neurotoxicity compared to single metal exposures, in particular during early life. Few studies have evaluated behavioral effects related to metal co-exposures.

show abstract

Effect of environmental manganese exposure on verbal learning and memory in Mexican children

Cited by 93 publications

References 40 publications

Cognitive Effects of Manganese in Children and Adults

Cognitive Effects of Manganese in Children and Adults

Prenatal and postnatal manganese teeth levels and neurodevelopment at 7, 9, and 10.5years in the CHAMACOS cohort

Perinatal and Childhood Exposure to Cadmium, Manganese, and Metal Mixtures and Effects on Cognition and Behavior: A Review of Recent Literature

Contact Info

Product

Resources

About