Every so many years a manganese study like this is published and each time the same alarming claims are made, with same limitations as before. These authors do not seem to have any knowledge of prior studies of risks from drinking water exposures. Manganese in drinking water has been studied for decades. Apparently, these study authors are not very well informed. Lastly, 375 children is too small a sample size to make claims concerning children in “North America.” The study findings only apply to the 375 children and weak associations provide us no new insights.
Oulhote Y, Mergler D, Barbeau B, Bellinger DC, Bouffard T, Brodeur ME, Saint-Amour D, Legrand M, Sauvé S, Bouchard MF. Neurobehavioral Function in School-Age Children Exposed to Manganese in Drinking Water. Environ Health Perspect. 2014 Sep 26.
BACKGROUND: Manganese neurotoxicity is well documented in individuals occupationally exposed to airborne particulates, but few data are available on risks from drinking water exposure.
OBJECTIVE: We examined associations of manganese exposure from water and hair manganese concentration with memory, attention, motor function, and parent- and teacher-reported hyperactive behaviors.
METHODS: We recruited 375 children and measured manganese in home tap water (MnW) and hair (MnH). We estimated manganese intake from water ingestion. Using structural equation modeling, we estimated associations between neurobehavioral functions and MnH, MnW, and manganese intake from water. Exposure-response relationships were evaluated using generalized additive models.
RESULTS: After adjusting for potential confounders, a standard deviation (SD) increase in log10 MnH was associated with a significant difference of -24% (95% CI: -36, -12%) SD in memory and -25% (95% CI: -41, -9%) SD in attention. The relations between log10 MnH and poorer memory and attention were linear. A SD increase in log10 MnW was associated with a significant difference of -14% (95% CI: -24, -4%) SD in memory, and this relation was nonlinear, with a steeper decline in performance at MnW above 100 µg/L. A SD increase in log10 manganese intake from water was associated with a significant difference of -11% (95% CI: -21, -0.4%) SD in motor function. The relation between log10 manganese intake and poorer motor function was linear. There was no significant association between manganese exposure and hyperactivity.
CONCLUSION: Exposure to manganese in water was associated with poorer neurobehavioral performances in children, even at low levels commonly encountered in North America.
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