EAL

FL: Fluoride and the Brain (2010)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To confirm and explain the relationship of elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals.

Inclusion Criteria:

Not reported.

Exclusion Criteria:

Not available.

Description of Study Protocol:

Recruitment

Not available

Design

An overview of the confirmation and explanations for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals. Authors report on their previous research on the PbB data for 400,000 children (250,000 in Massachusetts,150,000 in New York State and 6,000 from NHANES III) that consistently showed a statistically significant Risk Ratio around 2 for PbB.

The authors discussed the following issues:

Association of elevated PbB with SiFW
Elevated PbW effect on blood lead levels
Plumbing corrosion and PbW; Metabolism of ingested fluoride
Caries/Fluorosis/PbW/SiFW linkage
Incomplete dissociation of SiF in SiFW
SiF dissociation complexity; analysis for total fluoride; SiF adverse health effects
CDC’s dismissal of an SiF/PbB linkage.

Blinding used (if applicable)

None

Intervention (if applicable)

None

Statistical Analysis

None

Data Collection Summary:

Timing of Measurements

Not applicable

Dependent Variables

Lead content in water and lead content in blood

Independent Variables

SiF fluoridated communities and non-fluoridated communities

Control Variables

Blood lead levels and fluoridated and non-fluoridated communities

Description of Actual Data Sample:

Initial N

Previous research by authors was reported: PbB data for 400,000 children (250,000 in Massachusetts, 150,000 in New York State and 6,000 from NHANES III). NHANES III study participants by race and silicofluoride exposure ages three to 17.

Other studies were discussed that included animal and in vitro analyses.

Attrition (final N)

Age

Not reported in detail

Ethnicity

Not reported

Other relevant demographics

Not reported

Anthropometrics

Not reported

Location

Massachusetts, New York State and NHANES III data

Summary of Results:

Blood lead data reanalyzed 1 and confirming an association of silicofluoride with elevated blood lead for children aged one to 16 in NHANES III database.

WF status	Number sampled	Number with a PbB >5 mg/dL	Percentage with PbB >5 mg/dL (%)
SiF treated^b	3,170	524	16.5
All other ^c known	4,004	568	14.2

Odds Ratio: 1.20, Wald Chi-Square P-value: 0.006. Wald 95% Confidence Interval: (1.05, 1.36).

^a The standard criterion for elevated blood lead is greater than 10mg/dL; an OR of 1.2 found using greater than 5mg/dL predicts an OR greater then 1.2 using greater than 10mg/dL as the criterion

^b Fluosilicic acid and sodium silicofluoride combined

^c Natural, NaF treated, and non-fluoridated combined

¹ Macek MD, et al. Blood lead concentrations in Children and method of water fluoridation in the United States 1988–1994. Environ Health Perspect 2006; 114 (1): 130-134 In: http://ehp.niehs.nih.gov/members/2005/8319/8319.pdf.

Prevalence and adjusted odds of an elevated PbB concentration at the 5mg/dL cut-off for U.S. children one to 16 years of age, by water fluoridaticn method and year in which dwelling was built, 1988-1934 (n=9,477)^a

Water fluoridation method^b	Before 1946			1946-1973			1974-Present			Unknown
	No.	Percent	OR (95% CI)^d	No.	Percent	OR (95% CI)	No.	Percent	OR (95% CI)	No.	Percent	OR (95% CI)
Unknown/mixed status	473	24.7	0.9 (0.4-1.9)	837	11.4	1.1 (0.4-2.7)	674	8.3	1.2 (0.5-3.2)	319	21.9	3.8 (2.0-7.0)
Sodium silicofluoride	141	20.7^e	0.9 (0.3-2.8)	420	16.8	0.8 (0.3-2.5)	289	6.5^e	1.0 (0.4-2.5)	71	30.1	2.8 (0.8-9.8)
Hydrofluosilicic acid	448	30.1	1.2 (0.6-2.5)	839	14.7	1.4 (0.7-2.9)	605	5.4	1.7 (0.6-4.3)	257	24.7	5.3 (2.7-10.5)
Sodium fluoride	78	20.9	0.8 (0.3-1.7)	127	7.6^e	1.5 (0.4-5.3)	81	6.0^e	0.6 (0.1-4.6)	60	6.6^e	1.0 (0.3-3.6)
Natural fluoride	113	19.4	0.3 (0.1-01.6)	419	17.3	1.5 (0.7-3.2)	413	7.3^e	1.1 (0.3-3.8)	182	16.6	1.0 (0.4-2.2)
No fluoride	307	26.4	Reference	1176	16.0	Reference	707	6.4	Reference	341	18.4	Reference
Adjusted Wald-F P-value			<0.01			0.76			0.76			<0.01

^a From the Third National Health and Nutrition Examination Survey (1988-1994) and 1932 Fluoridation Census.

^b Weighted to reflect the civilian non-institutionalized population of the United States; persons with unknown blood lead levels were excluded from analysis.

^c Percentage of the population with an elevated blood lead concentration (≥5mg/dL).

^d Adjusted OR of an elevated blood lead concentration at the 5mg/dL cut-off, controlling for age, sex, race/ethnicity, poverty status, urbanicity and duration of residence.

^e Does not meet the standard for statistical reliability.

Other Findings

Prevalence of children with elevated blood lead (PbB greater than 10 mg/dL) is about double that in non-fluoridated communities (Risk Ratio 2, x² P<0.01)
SiFW is associated with serious corrosion of lead-bearing brass plumbing, producing elevated water lead (PbW) at the faucet
PbW contributes little to children’s blood lead (PbB), it is likely to contribute 50% or more
SiFW has been shown to interfere with cholinergic function
Chronic ingestion of SiFW is a major factor in the linkage of dental fluorosis with fluoridated water
Acetylcholine (ACh) modulated by acetylcholinesterase (AChE) also induces saliva flow. Intense salivation is a symptom of fluoride poisoning; less severe fluoride exposure should increase flow of fluoride bearing saliva.

Author Conclusion:

The authors concluded that the effect of PbW on elevated PbB in children has been underestimated on several counts: (a) a fetus exposed to lead in the mother’s blood released from her bones or ingested with her food and drink; (b) a newborn ingests more water per pound of body weight than an adult; (c) all children absorb more of the lead they ingest than adults; (d) their developmental state renders them more susceptible to neurotoxic damage; (e) lead in drinking water extracted from brass plumbing fixtures by combinations of disinfection and fluoridation chemicals is more important than previously thought and has not had the attention it deserves.

Funding Source:

Other:

Not reported

Reviewer Comments:

It is a prospective review study evaluating the association of PbW and PbB in non-fluoridated communities and fluoridated communities. In this paper, the methods of evaluating the data and confirmation for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals are not clear.

Comparison of different studies evaluating the ingested fluoride and blood lead levels also required. The details of chronic disorders are not clearly discussed.

The authors concluded that people living in communities with silicofluoride treated water (SiFW) is associated with two neurotoxic effects: 1. Prevalence of children with elevated blood lead (PbB greater than 10mg/dL) is about double that in non-fluoridated communities ( RR 2, X² P<0.01). 2. SiFW has been shown to interfere with cholinergic function. More information on these neurotoxic effects are required.

Quality Criteria Checklist: Review Articles
Relevance Questions
	1.	Will the answer if true, have a direct bearing on the health of patients?	Yes
	2.	Is the outcome or topic something that patients/clients/population groups would care about?	Yes
	3.	Is the problem addressed in the review one that is relevant to dietetics practice?	Yes
	4.	Will the information, if true, require a change in practice?	Yes

Validity Questions
	1.	Was the question for the review clearly focused and appropriate?	Yes
	2.	Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described?	No
	3.	Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased?	No
	4.	Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible?	Yes
	5.	Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined?	Yes
	6.	Was the outcome of interest clearly indicated? Were other potential harms and benefits considered?	Yes
	7.	Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described?	No
	8.	Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included?	Yes
	9.	Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed?	No
	10.	Was bias due to the review's funding or sponsorship unlikely?	Yes