Fluoride Exposure and Age of Menarche: Potential Differences Among Adolescent Girls and Women in the United States

Fluoride exposure is associated with later pubertal development and decreased testosterone production in adolescent and adult males. However, its effects on female reproductive health and pubertal development are unclear. Therefore, we examined associations of fluoride exposure with reproductive health outcomes among adolescent girls and women in the United States. Participants were from The National Health and Nutrition Examination Surveys (2013 to 2016), aged 16–19 and identified as female. There were 524 and 460 participants with measures of plasma fluoride and household tap water fluoride respectively, who had at least one reproductive health outcome examined, and complete covariate data. We applied covariate adjusted survey-weighted linear or logistic regression to examine associations of fluoride exposure with age of menarche, menstrual cycle regularity, or serum sex steroid hormone levels. Median interquartile range (IQR) water and plasma fluoride concentrations were 0.48 (0.53) mg/L and 0.34 (0.30) µmol/L respectively. An IQR increase in water fluoride was associated with a 3.3 month earlier first menstrual period (B = − 0.28, 95%CI − 0.54, − 0.02, p = 0.05). Additionally, we observed a significant interaction between plasma fluoride and race/ethnicity in association with age of menarche (p = 0.01). Among Non-Hispanic Black adolescents, each IQR increase in plasma fluoride was associated with a 5-month earlier age of menarche (B = − 0.42, 95%CI − 0.61, − 0.23, p < 0.001). Potential impacts of chronic low-level fluoride exposure on reproductive health outcomes are an important area of study. Current study findings, as well as potential health disparities due to disproportionate fluoride exposure should be examined in prospective studies.

Fluoride Exposure through Different Drinking Water Sources in a Contaminated Basin in Guanajuato, Mexico: A Deterministic Human Health Risk Assessment

Water fluoride levels above the World Health Organization’s guideline (1.5 mg/L), common in overexploited aquifers, represent a health hazard. Our objective was to assess the health risks posed by exposure to fluoride in different drinking water sources in a contaminated basin in Mexico. Fluoride was measured in mutual drinking water sources and in the urine of 39 children and women. Risks were estimated through hazard quotient (HQ) by drinking water source. Dental fluorosis was assessed in the children. Mean fluoride water concentrations (mg/L) were: well, 4.2; waterhole, 2.7; bottled, 2.1; rainwater, 0.4. The mean urinary fluoride concentrations (specific gravity adjusted) were 2.1 mg/L and 3.2 mg/L in children and women, respectively. Our multiple linear regression model showed children’s urinary fluoride concentrations increased 0.96 mg/L for every 1 mg/L increase in water fluoride (p < 0.001). Dental fluorosis was diagnosed in 82% of the children, and their HQ according to drinking water source was: well, 1.5; waterhole, 1.1; bottled, 0.8; harvested rainwater, 0.3. The pervasive dental fluorosis indicates a toxic past fluoride exposure; urinary fluoride levels and HQs indicate high exposure and current health risks for most children. Drinking harvested rainwater will likely prevent most of the local fluoride exposure.

Geospatial Variability Analysis of Fluoride Quantification in Underground Aquifers of Central Parts of Haryana State, India

The elevated levels of fluoride in underground water enhance the prevalence of the fluorosis epidemic in Haryana state. To assess the groundwater geospatial variability of fluoride at different depths in central parts of Haryana, the present study has been explored. The samples at eight sites were collected in triplicate at 3 depth levels viz. a) < 10 m below ground level (bgl), b) 10-40 m bgl, and c) > 40 m bgl. Fluoride levels have been determined by the SPADANS-zirconyl oxychloride method using UV-VIS spectrophotometer (Systronics-118). The fluoride concentration varies from 0.19 mg/L to 2.87 mg/L. More than 38 percent of samples exceed the standard prescribed limit of 1.0 mg/L fluoride in drinking water. Fluoride contamination increases in post-monsoon samples with maximum concentration at 40 bgl depth. Due to geological factors (fluoride-bearing minerals in basement rocks) and human-induced (brick-kiln industries, phosphatic fertilizers) factors, a high concentration of fluoride in groundwater is observed. Sustainable defluoridation techniques and a good diet (calcium & vitamin c enriched) can control the adverse effects of fluorosis.

Dental caries and its association with increasing water fluoride concentration in district Rudraprayag, Uttarakhand

Background: Evidence from scientific literature confirms both beneficial and detrimental effects of fluoride on human health with only a narrow range between intakes associated with these effects. The limits of this range have been controversial among researchers since the 1930s. Considering this, the World Health Organization (WHO) permissible limit of fluoride in India has been reduced from 1.5 to 1.0 mg/l in 1998. This study aimed to evaluate the association between increasing water fluoride levels and dental caries prevention on permanent teeth.Methods: This cross-sectional study involved 1400 children (aged 6–19 years). Caries experience and dental fluorosis were recorded using DMFT/deft and Dean's index respectively. Also, fluoride concentration in drinking water was analyzed. Around 14.4% of children had dental caries with maximum frequency among 9-10 years of age. A significant negative correlation between caries experience and water fluoride level was found (p<0.05), with the lowest DMFT scores at the fluoride level of 0.61–2 mg/l and the highest at 0.0–0.3 mg/l. Whereas, high prevalence of dental fluorosis was observed above 0.7 mg/l.Results: The study revealed that the presence of 0.3-0.7 mg/l fluoride in drinking water reduces dental caries, without an objectionable rise in dental fluorosis.Conclusions: It can be suggested that fluoride has anticaries property but due to a ‘narrow therapeutic window’ of 0.3-0.7 mg/l, in a country like India where endemic fluorosis is prevalent, its topical application should be encouraged which is almost equally effective with less systemic adverse effects.

Association Between Osteoarthritis and Water Fluoride Among Tongyu Residents, China 2019: A Case-control of Population-based Study

Background: Fluoride is an environmental chemical that has adverse effects on health, probably increasing osteoarthritis (OA) risk. However, whether fluoride is a serious risk factor for OA is still inconsistent among current evidence. The aim of this study was to determine the relationships between chronic fluoride exposure and OA risk among the residents living in Tongyu County, China 2019.Method: 186 cases and 186 controls aged 26 to 86 years were recruited after x-ray examination with Kellgren and Lawrence criteria by two independent evaluators. Urinary fluoride (UF) in a spot sample was measured by fluoride ion-selective electrode, and water fluoride data were used as community level of exposure. Associations between fluoride exposure and OA risk were examined by the unconditional logistic regression. Covariates included age, gender, body mass index, duration of living, daily water drunk, income, sport and filter use with stratified analysis.Results: Mean UF concentration 2.54 ± 1.22 mg/L was higher than the mean of community water fluoride concentration 1.49 ± 0.32 mg/L. The mean UF concentration 2.73 ± 1.18 mg/L was significantly higher in cases compared to 2.35 ± 1.24 mg/L in controls group (p < 0.02). In full sample analysis, a 1mg/L increase in UF level was associated with a 27% higher risk of OA (95% CI: 1.06 - 1.52, p = 0.008), and 4th quartile participants were associated with higher risk when compared to 1st quartile (OR: 2.46, 95% CI: 1.34 – 4.57, p = 0.003). In stratified analysis, compared to 1st quartile, 4th quartile participants were 4 times more likely to have OA (95% CI: 1.86 – 8.82, p = 0.000) in the non-obese group, 7.7 times more likely to have OA (95% CI: 2.58 – 25.05, p = 0.000) among adults ≤ 60-year and 12 times more likely to have OA (95% CI: 2.15 – 99.65, p = 0.008) in non-obese adult women ≤ 60-year group.Conclusion: Water fluoride exposure may increase OA risk and could have more impact on a specific group such as non-obese and adult ≤ 60-year population.

Urinary Fluoride Levels among Canadians with and without Community Water Fluoridation

Drinking water is a major source of dietary fluoride intake in communities with water fluoridation. We examined the association between urinary fluoride adjusted for specific gravity (UFSG) and tap water fluoride levels, by age and sex, among individuals living in Canada. Participants included 1629 individuals aged 3 to 79 years from Cycle 3 (2012–2013) of the Canadian Health Measures Survey. We used multiple linear regression to estimate unique associations of tap water fluoride levels, age, sex, ethnicity, body mass index (BMI), use of fluoride-containing dental products, smoking in the home, and tea consumption with UFSG. UFSG concentration was significantly higher among participants who received fluoridated drinking water (mean = 1.06 mg/L, standard deviation = 0.83) than among those who did not (M = 0.58 mg/L, SD = 0.47), p < 0.01. UFSG increased over adulthood (ages 19 to 79). Higher UFSG concentration was associated with being female, tea drinking, and smoking in the home. In conclusion, community water fluoridation is a major source of contemporary fluoride exposure for Canadians. Lifestyle factors including tea consumption, as well as demographic variables such as age and sex, also predict urinary fluoride level, and are therefore important factors when interpreting population-based fluoride biomonitoring data.

Fluoride Content in Drinking Water and the Health Implications of Fluoride-Rich Water Consumption: An Overview of the Situation in Canada and Nigeria

Fluoride is an inorganic monatomic anion of fluorine and forms part of essential reagents used by the chemical industry. It occurs naturally in several minerals and in trace quantities in water. Fluoride has been used to prevent tooth decay and in the treatment of osteoporosis. Extensive research has consistently demonstrated the safety and effectiveness of fluorides in the prevention of dental caries following the practice of water fluoridation. Despite these benefits, fluorides pose danger as an endocrine disruptor thus, affecting bones, brain, thyroid gland, pineal gland and blood sugar levels. In Canada, water fluoridation remains a contentious issue although dental decay constitutes the most common chronic disease. However, several Canadians are receiving the benefits of water fluoridation and about 1% have access to naturally fluoridated water. In Nigeria, the prevalence of dental caries has been documented to be greatly reduced following fluoridation of public water supplies in areas where the condition was endemic. Fluoride is therefore the only medicine added to public water, and at the recommended level, fluoride is safe and effective in the reduction of dental decay and poses no risk for health problems. Hence, this article highlighted fluoride content in drinking water and the health implications of consuming fluoride-rich water with a focus on the situation in Canada and Nigeria.

Tendürek Sönmüş Yanardağının Florotoksik Kaynak Suları Örneğinde Doğal Florozisin Çiftlik Hayvanı Kemiklerinin Flor Düzeyleri Üzerine Etkisi

It is known that the level of Fluoride in the spring waters from some volcanic lands is high and these waters cause Fluoride toxicity. Scientific studies have shown that in Doğubayazıt there is high amount of fluoride in some spring waters originating from the foothills of Tendürek volcano and normal level in Iğdır and Cappadocia volcanic lands. In this study, it was revealed comparatively how the spring waters in these regions affect the bone Fluoride levels of farm animals that are given as drinking water. Fluoride analyses in bone, water and urine samples were performed by means of an ion meter equipped with an iron selective electrode (ISE). The urine and bone fluoride levels of farm animals followed a similar course to water samples. Fluoride levels in bone and urine samples of Doğubayazıt were detected to be significantly higher in compared to Igdır and Cappadocia regions. Bone Fluoride analysis results were also supported by external bone and dental examination findings. The presence of a strong relationship between the analysed water, urine and bone Fluoride levels was determined in this study. It was found that drinking water has a very strong effect on urine and bone in terms of fluoride level. Consequently, Fluorine levels in the bones of farm animals drinking water with high Fluorine levels originating from Tendürek Mountain in Doğubayazıt were found to be higher than normal. Fluoride levels in the bones of farm animals that drank high-fluoride waters originating from Tendurek mountain in Doğubayazıt were found to be higher than normal. This situation can be evaluated as evidence that natural Fluoride toxicity formed by drinking water causes Fluoride accumulation on bones.