Fluoride Action Network

Abstract

Highlights

  • Childhood fluoride exposure may adversely affect kidney function in preadolescence.
  • Adiposity status could modify the association between fluoride and kidney function.
  • Null associations found between 4-year Fluoride and preadolescent kidney function.
  • Among children with obesity, we observed an inverse association F-kidney function.
  • It is possible that the preadolescent age was too young to observe any associations.

Background

Early-life renal maturation is susceptible to nephrotoxic environmental chemicals. Given the widespread consumption of fluoride and the global obesity epidemic, our main aim was to determine whether childhood fluoride exposure adversely affects kidney function in preadolescence, and if adiposity status modifies this association.

Methods

Our study included 438 children from the PROGRESS cohort. Urinary fluoride (uF) was assessed at age 4 by diffusion analysis; outcomes studied included estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), selected kidney proteins and blood pressure measured at age 8–12 years. We modeled the relationship between uF and outcomes, and adjusted for body mass index (BMI), age, sex, and socioeconomic status.

Results

The median uF concentration was 0.67 ug/mL. We observed null associations between 4-year uF and preadolescent eGFR, although effect estimates were in the expected inverse direction. A single unit increase in ln-transformed uF was associated with a 2.2 mL/min decrease in cystatin C-based eGFR (95% CI: 5.8, 1.4; p = 0.23). We observed no evidence of sex-specific effects or effect modification by BMI status. Although uF was not associated with BMI, among children with obesity, we observed an inverse association (B: 4.8; 95% CI: 10.2, 0.6; p = 0.08) between uF and eGFR.

Conclusions

Low-level fluoride exposure in early childhood was not associated with renal function in preadolescence. However, given the adverse outcomes of chronic fluoride consumption it is possible that the preadolescent age was too young to observe any effects. Longitudinal follow-up in this cohort and others is an important next step.


*Original abstract online at https://www.sciencedirect.com/science/article/abs/pii/S0013935121013098?via%3Dihub