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Developmental biology - ADHD

High Levels Of Fluoride Found In ADHD Kids

Higher levels of urinary fluoride during pregnancy are associated with more ADHD-like symptoms in school-age children...

Higher levels of urinary fluoride during pregnancy are associated with more ADHD-like symptoms in school-age children, according to University of Toronto and York University researchers.
"Our findings are consistent with a growing body of evidence suggesting that the growing fetal nervous system may be negatively affected by higher levels of fluoride exposure."

Morteza Bashash PhD, Assistant Professor, University of Toronto, Dalla Lana School of Public Health, and the study's lead author and researcher.

The study, published in Environment International, analyzed data from 213 mother-child pairs in Mexico City that were part of the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) project, which recruited pregnant women from 1994 to 2005 and has continued to follow them and their children ever since.

Tap water and dental products have been fluoridated in communities in Canada and the United States (as well as milk and table salt in some other countries) by varying amounts for more than 60 years to prevent cavities. In recent years, fierce debate over the safety of water fluoridation - particularly as it might affect children's developing brains - has fueled research to provide evidence to inform national drinking water standards.

Research teams, including experts from the Universities of Toronto, York University, the National Institute of Public Health of Mexico, University of Michigan, Indiana University, the University of Washington and Harvard School of Public Health, analyzed urine samples obtained from moms during pregnancy and their children between the ages of six and 12 years old. Their aim was to reconstruct personal measures of fluoride exposure for both mother and child.

Researchers analyzed how levels of fluoride in urine related to each child's performance on a variety of tests and questionnaires measuring inattention and hyperactivity, which provided an overall score related to ADHD. Analyses were adjusted for other factors known to impact neurodevelopment, such as gestational age at birth, birthweight, birth order, sex, maternal marital status, smoking history, age at delivery, education, socioeconomic status and lead exposure.
"Our findings show that children with elevated prenatal exposure to fluoride were more likely to show symptoms of ADHD as reported by parents. Prenatal fluoride exposure was more strongly associated with inattentive behaviours and cognitive problems, but not with hyperactivity."

Morteza Bashash PhD.

This work builds off of previous research published by this same team on this population demonstrating that higher levels of urine fluoride during pregnancy are associated with lower scores on tests of IQ and cognition in the school-age children.ADHD is the most common psychiatric disorder diagnosed in childhood, affecting between five and nine per cent of all school-aged children.
"The symptoms of ADHD often persist into adulthood and can impair daily life. If we can understand the reasons behind this association, we can begin to develop preventive strategies to mitigate the risk."

Christine Till PhD, Associate Professor, Psychology York University, Principal Investigator of National Institutes of Health-funded grant examining fluoride exposure in a large Canadian sample of pregnant women.

• We measured urinary fluoride in 213 pregnant women living in Mexico City who were part of the ELEMENT pregnancy cohort study.

• Higher concentration of maternal urinary fluoride was associated with more ADHD-like symptoms in school-age children.

• Prenatal exposure to fluoride was most strongly associated with behavioral ratings of inattention, but not hyperactivity and impulse control.

• Findings are consistent with the growing body of evidence suggesting neurotoxicity of early-life exposure to fluoride.

Epidemiologic and animal-based studies have raised concern over the potential impact of fluoride exposure on neurobehavioral development as manifested by lower IQ and deficits in attention. To date, no prospective epidemiologic studies have examined the effects of prenatal fluoride exposure on behavioral outcomes using fluoride biomarkers and sensitive measures of attention.

We aimed to examine the association between prenatal fluoride exposure and symptoms associated with attention-deficit/hyperactivity disorder (ADHD).

213 Mexican mother-children pairs of the Early Life Exposures to Environmental Toxicants (ELEMENT) birth cohort study had available maternal urinary samples during pregnancy and child assessments of ADHD-like behaviors at age 6–12. We measured urinary fluoride levels adjusted for creatinine (MUFcr) in spot urine samples collected during pregnancy. The Conners' Rating Scales-Revised (CRS-R) was completed by mothers, and the Conners' Continuous Performance Test (CPT-II) was administered to the children.

Mean MUFcr was 0.85?mg/L (SD?=?0.33) and the Interquartile Range (IQR) was 0.46?mg/L. In multivariable adjusted models using gamma regression, a 0.5?mg/L higher MUFcr (approximately one IQR higher) corresponded with significantly higher scores on the CRS-R for DSM-IV Inattention (2.84 points, 95% CI: 0.84, 4.84) and DSM-IV ADHD Total Index (2.38 points, 95% CI: 0.42, 4.34), as well as the following symptom scales: Cognitive Problems and Inattention (2.54 points, 95% CI: 0.44, 4.63) and ADHD Index (2.47 points; 95% CI: 0.43, 4.50). The shape of the associations suggested a possible celling effect of the exposure. No significant associations were found with outcomes on the CPT-II or on symptom scales assessing hyperactivity.

Higher levels of fluoride exposure during pregnancy were associated with global measures of ADHD and more symptoms of inattention as measured by the CRS-R in the offspring.

Morteza Bashasha, Maelle Marchand, Howard Hu, Christine Till, E. Angeles Martinez-Mier, Brisa N.Sanchez, Niladri Basue, Karen E.Peterson, Rivka Green, Lourdes Schnaas, Adriana Mercado-García, Mauricio Hernández-Avila, Martha María Téllez-Rojo.

The National Institute of Environmental Health Sciences, part of the National Institutes of Health (NIH), funded this study.

About Children's Hospital of Philadelphia: Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals, and pioneering major research initiatives, Children's Hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country. In addition, its unique family-centered care and public service programs have brought the 546-bed hospital recognition as a leading advocate for children and adolescents. For more information, visit http://www.chop.edu

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Oct 17, 2018   Fetal Timeline   Maternal Timeline   News   News Archive

In recent years, debate over the safety of fluoride in water - particularly as it affects children's brains - has fueled research to better inform national drinking water standards. Image Credit: Public Domain.

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