What is the headline saying?

Link to article Prenatal Fluoride Exposure Linked to ADHD in Kids

What is the article saying?

Prenatal exposure to higher levels of fluoride not only impairs cognitive development but also significantly increases the incidence of attention-deficit/hyperactivity disorder (ADHD) in children, new research shows.

…it is the first [study] to find an increased incidence of ADHD with prenatal fluoride exposure.

We observed a positive association between higher prenatal fluoride exposure and more behavioral symptoms of inattention, which provide further evidence suggesting neurotoxicity of early-life exposure to fluoride.

Does the headline ultimately support claims made by the article? Does it summarize key points of the article?

Yes. However, the lead author makes sure to say that this study does not summarize the debate about whether or not fluoride should be added to water sources. See below:

For the past 50 years, the medical establishment has claimed that fluoride is safe and effective; should the official position on fluoridation change? I do not believe our study alone can be used to answer this question.

What are the implications of the headline and article?

Countries and geographical areas that artificially add fluoride to water, have it naturally occurring in the environment, or add it to salt are putting fetuses and, consequently, kids at risk for ADHD.

They fuel the debate about whether or not fluoride should be removed from the drinking water in countries that have implemented this public health intervention.

What evidence currently exists to counter or support these implications?

Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015) https://www.nature.com/articles/sj.bdj.2017.988

Fluoride exposure and reported learning disability diagnoses among Canadian children: Implication for community water fluoridation https://www.ncbi.nlm.nih.gov/ pubmed/28910243

Exposure to fluoridated water and attention deficit hyperactivity disorder prevalence among children and adolescents in the United States: and ecological association https:// www.ncbi.nlm.nih.gov/pmc/articles/PMC4389999/

Are there similar and/or opposing headlines from other news outlets? Do the news outlets only link back to other news outlets?

There are similar headlines all tied to the same study – Google Search

What are the data sources (i.e., memo, official statement, official document, research study, validated surveillance system, official report, etc.) supporting the article?

Research Study: Prenatal fluoride exposure and attention deficit hyperactivity disorder (ADHD) symptoms in children at 6-12 years of age in Mexico City.

Are these data sources credible when applied to the news story? Why or why not?

Data source is not credible due to limitations of the study. Please continue reading for more details. Also, please read the limitations section of the study:

Study participants:

Three different cohorts of women in the Early Life Exposures to Environmental Toxicants (ELEMENT) birth cohort study with available maternal urinary samples during pregnancy, along with child assessments of ADHD-like behaviors at age 6-12.

Methods

Screening for ADHD:

To measure fluoride levels in urine:

The 24-hour urine collection should be used wherever possible…but 14–16 or even 8-hour collection can be used if necessary. Where 24-hour or continuous supervised collection periods are not possible, spot samples of urine can sometimes provide valuable information…

A spot urine sample is defined as an un-timed “single-void” urine sample. This method is the least informative method for studying fluoride exposure, because the amount of fluoride excreted per day or per hour cannot be calculated from the concentration alone. If spot samples are collected, it is best to take them at several times within a day. Urine that has accumulated in the bladder over a short period may reflect a short-lived peak level of the fluoride concentration. Hence, the longer the urine is retained in the bladder, the more representative it is of 24-hour results. For each spot sample, the hour when it was obtained should be recorded. When spot samples are collected in a follow-up assessment of urinary fluoride, the time of day at which the urine is passed should be approximately equal to the collection times in the initial excretion study. In programmes where fluoride is given once or twice per day, spot urine samples are not useful unless they are scheduled in such a way as to be directly associated with the fluoride intake.

Attention outcomes of interest:

Covariates:

Data analysis (after univariate and bivariate analysis):

Results

Only 10% of mother-child pairs fell within clinically significant range for CRS-R and MUFcr (average of all urinary samples)

Furthermore:

Sensitivity analyses did not change CRS-R scores

Observations of MUFcr and CRS-R suggest that higher levels of urinary fluoride concentration did not increase ADHD-like symptoms

Limitations

From article:

My additions:

Conclusion

From authors of the study:

In summary, we observed a positive association between higher prenatal fluoride exposure and more behavioral symptoms of inattention, but not hyperactivity or impulse control, in a larger Mexican cohort of children aged 6 to 12 years. The current findings provide further evidence suggesting neurotoxicity of early-life exposure to fluoride. Replication of these findings is warranted in other population-based studies employing biomarkers of prenatal and postnatal exposure to fluoride.

What does this mean for the general public?

The headline and news article mirror the conclusions made by the authors, however, the claims by the authors that their findings provide evidence that suggests neurotoxicity of early-life exposure to fluoride are not valid based on the limitations of this study (many of which the authors point out themselves).