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Updated: Jul 9, 2025
Author Spotlight: Studying the Impact of Maternal Dietary Deficiencies on Long-Term Offspring Health Outcomes
Published on: June 28, 2024
Prenatal fluoride exposure, offspring visual acuity and autonomic nervous system function in 6-month-old infants
John E Krzeczkowski1, Meaghan Hall2, Dave Saint-Amour3
1Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada.
Insights
Prenatal exposure to fluoride in drinking water was linked to poorer infant vision and altered heart rate variability (HRV). This study suggests potential developmental neurotoxicity from fluoride, impacting infant health outcomes.
Area of Science:
- Environmental Health
- Developmental Pediatrics
- Toxicology
Background:
- Prenatal fluoride exposure's impact on child development is a growing concern.
- Previous research indicates potential adverse effects, but links to visual and cardiac autonomic nervous system function remain unclear.
Purpose of the Study:
- To investigate the association between prenatal fluoride exposure and visual acuity in 6-month-old infants.
- To examine the relationship between prenatal fluoride exposure and heart rate variability (HRV) in 6-month-old infants.
Main Methods:
- Utilized data from the Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) cohort.
- Assessed prenatal fluoride exposure via drinking water concentration, maternal urinary fluoride (MUFSG), and maternal fluoride intake.
- Employed multivariable linear regression to analyze associations with infant visual acuity and HRV (RMSSD, SDNN).
Main Results:
- Higher drinking water fluoride concentration correlated with poorer infant visual acuity and lower RMSSD (a measure of HRV).
- Increased maternal fluoride intake was also associated with reduced visual acuity and lower RMSSD.
- No significant associations were found between maternal urinary fluoride (MUFSG) and the measured infant outcomes.
Conclusions:
- Fluoride in drinking water is associated with diminished visual acuity and altered cardiac autonomic function in infants.
- These findings contribute to the evidence suggesting fluoride's potential role in developmental neurotoxicity.
- Further research is warranted to understand the full spectrum of fluoride's developmental effects.
Background:
Prenatal fluoride exposure can have adverse effects on children's development; however, associations with visual and cardiac autonomic nervous system functioning are unknown. We examined associations between prenatal fluoride exposure and visual acuity and heart rate variability (HRV) in 6-month-old infants.
Methods:
We used data from Canadian mother-infant pairs participating in the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort. We estimated prenatal fluoride exposure using: i) fluoride concentration in drinking water (mg/L), ii) maternal urinary fluoride adjusted for specific gravity (MUFSG; mg/L) and averaged across pregnancy, and iii) maternal fluoride intake (µg/kg/day) from consumption of water, tea, and coffee, adjusted for maternal body weight (kg). We used multivariable linear regression to examine associations between each measure of fluoride exposure and Teller Acuity Card visual acuity scores (n = 435) and assessed HRV (n = 400) using two measures: root mean square of successive differences (RMSSD) and the standard deviation of N-N intervals (SDNN) measured at 6-months of age.
Results:
Median (IQR) values for water fluoride, MUFSG, and daily fluoride intake were 0.20 (IQR: 0.13-0.56) mg/L; 0.44 (0.28-0.70) mg/L and 4.82 (2.58-10.83) µg/kg/day, respectively. After adjustment for confounding variables, water fluoride concentration was associated with poorer infant visual acuity (B = -1.51; 95 % CI: -2.14,-0.88) and HRV as indicated by lower RMSSD (B = -1.60; 95 % CI: -2.74,-0.46) but not SDNN. Maternal fluoride intake was also associated with poorer visual acuity (B = -0.82; 95 % CI: -1.35,-0.29) and lower RMSSD (B = -1.22; 95 % CI: -2.15,-0.30). No significant associations were observed between MUFSG and visual acuity or HRV.
Conclusion:
Fluoride in drinking water was associated with reduced visual acuity and alterations in cardiac autonomic function in infancy, adding to the growing body of evidence suggesting fluoride's developmental neurotoxicity.
