Amelioration of chronic fluoride toxicity by calcium and fluoride-free water in rats

Relationships between dental fluorosis and fluoride concentrations in bottled water and groundwater in low-income children in Mexico

Introduction

The aim of the current study was to investigate associations between dental fluorosis in children living in low socioeconomic areas in Mexico, and fluoride concentrations in tap water, fluoride concentrations and in bottled water, and body mass index (BMI).

Methods

A cross-sectional study involving 585 schoolchildren aged 8-12 years was conducted in communities in a southern state of Mexico with >0.7 parts per million (ppm) fluoride in the groundwater. The Thylstrup and Fejerskov index (TFI) was used to evaluate dental fluorosis, and the World Health Organization growth standards were used to calculate age-adjusted and sex-adjusted BMI Z-scores. A BMI Z-score ≤ -1 SD was used as the cut-off point for thinness, and multiple logistic regression models for dental fluorosis (TFI ≥ 4) were constructed.

Results

The mean fluoride concentration in tap water was 1.39 ppm (SD 0.66), and the mean fluoride concentration in bottled water was 0.32 ppm (SD 0.23). Eighty-four children (14.39%) had a BMI Z-score ≤ -1 SD. More than half (56.1%) of the children presented with dental fluorosis in TFI categories ≥ 4. Children living in areas with higher fluoride concentrations in the tap water [odds ratio (OR) 1.57, p = 0.002] and bottled water (OR 3.03, p < .001) were more likely to have dental fluorosis in the severe categories (TFI ≥ 4). BMI Z-score was associated with the probability of dental fluorosis (TFI ≥ 4; OR 2.11, p < 0.001), and the effect size was 29.3%.

Discussion

A low BMI Z-score was associated with a higher prevalence of dental fluorosis in the severe category. Awareness of the fluoride concentrations in bottled water may help prevent dental fluorosis, particularly in children exposed to several high fluoride content sources. Children with a low BMI may be more vulnerable to dental fluorosis.

Supplementation of Calcium and Fluoride-Free Water Mitigates Skeletal Fluorosis in Fluoride-Intoxicated Rats

Fluorosis is a public health concern in 25 countries around the globe. The present study is about the mitigation of fluoride (F) toxicity by giving F-free water (FFW) and calcium (Ca). A study was conducted by taking 76 Wistar rats in two phases, phase I (6 months), where rats were randomly divided into four groups: normal-Ca diet (NCD) 0.5%; low-Ca diet (LCD) 0.25%; NCD + 100 ppm F and LCD + 100 ppm F in groups 1, 2, 3 and 4, respectively. F and Ca were given through water and diet respectively. Phase II is the reversal of fluorosis for 3 months, where LCD group 2 was treated with NCD. Groups 3 and 4 were divided into two subgroups each: 3X and 3Y, and 4X and 4Y, respectively. Groups 3X and 4X received FFW with NCD. Group 3Y continued as phase I and 4Y NCD and F. The biochemical expression, gene expression, biomechanical properties and DXA were studied by standard methods. The results revealed that in phase I, bone turnover was significantly increased whereas bone mineral content and biomechanical properties of group 4 were significantly decreased (p ≤ 0.05) as compared with that of all other groups. Trabecular separation and total porosity increased in groups 2 and 4. Expression of osteocalcin, osteonectin and osteopontin genes was significantly downregulated in group 4. Bone turnover in group 4X was normalised. Expressions of osteocalcin, osteonectin and osteopontin were upregulated after providing NCD and FFW. In conclusion, low calcium aggravates skeletal fluorosis which could be mitigated on supplementation of Ca and FFW.

Dose-dependent effect of fluoride on clinical and subclinical indices of fluorosis in school going children and its mitigation by supply of safe drinking water for 5 years: an Indian study

Fluorosis is a public health problem in India; to know its prevalence and severity along with its mitigation measures is very important. The present study has been undertaken with the aim to assess the F dose-dependent clinical and subclinical symptoms of fluorosis and reversal of the disease by providing safe drinking water. For this purpose, a cross-sectional study was undertaken in 1934 schoolgoing children, Nalgonda district. Study villages were categorized into control (category I, F = 0.87 mg/L), affected (category II, F = 2.53 mg/L, and category III, F = 3.77 mg/L), and intervention categories (category IV, F = < 1.0 mg/L). School children were enrolled for dental grading by modified Dean Index criteria. Anthropometric measurements (height and weight) were used to assess nutritional status of the children. The biochemical parameters like serum T3, T4, TSH, PTH, ALP, 25-OH vitamin D, and 1,25-(OH)₂ vitamin D were analyzed. The results showed a positive correlation between the drinking water and urinary fluoride (UF) in different categories. However, there was a significant decrease in the UF levels in the intervention category IV compared to affected group (category III). Fluoride altered the clinical (dental fluorosis and stunting) and subclinical indices (urine and blood) of fluorosis in a dose-dependent manner. In conclusion, the biochemical indices were altered in a dose-dependent manner and intervention with safe drinking water for 5 years in intervention group-mitigated clinical and subclinical symptoms of fluorosis.

Dental fluorosis, nutritional status, kidney damage, and thyroid function along with bone metabolic indicators in school-going children living in fluoride-affected hilly areas of Doda district, Jammu and Kashmir, India

A case-control study was undertaken among the school children aged 8-15 years to know the presence and severity of dental fluorosis, nutrition and kidney status, and thyroid function along with bone metabolic indicators in Doda district situated at high altitude where drinking water was contaminated and heat stress. This study included 824 participants with an age of 8-15 years. The results of the study reviled that dental fluorosis was significantly higher in affected than control area children. Urinary fluoride was significantly higher (p < 0.05) in affected children as compared to the control area school children. Nutritional status of affected children was lower than control area children. The chronic kidney damage (CKD) was higher in affected than control school children. Thyroid function was affected more in affected than control area schools. Serum creatinine, total alkaline phosphatase, parathyroid hormone, 1, 25(OH)₂ vitamin D, and osteocalcin were significantly higher in affected school children (p < 0.05) as compared to control school children, whereas there was no significant difference in triiodothyronine (T3), thyroxine (T4), and 25-OH vitamin D among the two groups. There was a significant decrease in thyroid-stimulating hormone (TSH) in the affected area school children compared to control. In conclusion, fluorotic area school children were more affected with dental fluorosis, kidney damage, along and some bone indicators as compared to control school children.