- Plasma fluoride is related to lower testosterone and estradiol in male adolescents.
- Water fluoride is inversely associated with SHBG in male adolescents.
- Plasma fluoride is inversely associated with SHBG in female children.
Fluoride mediated disruption of sex steroid hormones has been demonstrated in animals. However, evidence from humans was limited and contradictory, especially for children and adolescents. Based on data of the National Health and Nutrition Survey (NHANES) 2013–2016, a total of 3392 subjects aged 6–19 years were analyzed in this cross-sectional study. Both plasma and water fluoride levels were quantified electrometrically using the ion-specific electrode. Sex steroid hormones of total testosterone, estradiol and sex hormone-binding globulin (SHBG) were tested in serum. Percent changes and 95% confidence intervals (CIs) in sex steroid hormones associated with tertiles of fluoride levels (setting the first as reference) were estimated using adjusted linear regression models by stratification of gender and age. Compared with subjects at the first tertile of plasma fluoride, percent changes (95% CIs) in testosterone were -8.08% (-17.36%, 2.25%) and -21.65% (-30.44%, -11.75%) for the second and third tertiles, respectively (P trend <0.001). Male adolescents at the third tertile of plasma fluoride had decreased levels of testosterone (percent change = -21.09%, 95% CIs = -36.61% to -1.77%). Similar inverse associations were also found when investigating the relationships between plasma fluoride and estradiol. Besides, the data indicated decreased levels of SHBG associated with water and plasma fluoride among the male adolescents (percent change of the third tertile = -9.39%, 95% CIs = -17.25% to -0.78%) and female children (percent change of the second tertile = -10.78%, 95% CIs = -17.55% to – 3.45%), respectively. The data indicated gender- and age-specific inverse associations of fluoride in plasma and water with sex steroid hormones of total testosterone, estradiol and SHBG in U.S. children and adolescents. Prospective cohort studies are warranted to confirm the causality.
A Rat Experimental Study of the Relationship Between Fluoride Exposure and Sensitive Biomarkers.
Chronic excessive fluoride exposure impairs human health and damages not only the skeletal system and the teeth but also the soft tissues such as the brain, liver, kidneys, pancreas and spinal cord. However, there is limited research regarding the exposure levels and sensitive biomarkers. This study was aimed to establish
Selenium may suppress peripheral blood mononuclear cell apoptosis by modulating HSP70 and regulate levels of SIRT1 through reproductive hormone secretion and oxidant stress in women suffering fluorosis.
Excessive taking fluoride (F) causes severe damage to reproductive system through stimulation of apoptosis and oxidant stress. Selenium (Se) may promote anti-oxidant enzymes and invert cell apoptosis. The aim of this study was to investigate the effect of Se on peripheral blood mononuclear cell (PBMC) apoptosis and oxidant stress in
Analysis of the MicroRNA Profile by Sequencing in Ovarian Granular Cells from Women Suffering Fluorosis with Reproductive Dysfunction.
Excessive intake of fluoride may cause female reproductive dysfunction but pathological mechanism is unclear. The miRNAs in follicular fluid are a class of small non-coding RNAs from granulosa cells. The aim of this study is to examine the differential expressions of miRNAs in ovarian granulosa cells from women suffering from
Studies on fluorosis in Mehsana District of North Gujarat.
A survey was conducted in eighteen fluoride endemic villages in Mehsana District of North Gujarat (India). The individuals afflicted with fluorosis were examined for apparent mottled teeth and skeletal complications. Samples of urine and blood of these individuals along with drinking water were collected and compared with samples obtained from
[Osteoporosis therapy and thyroid function. Influence of 6 months of sodium fluoride treatment on thyroid function and bone density]
26 women were treated for osteoporosis with 40 mg of sodium fluoride twice a day (equivalent 36 mg of fluorine) for a longer period. Mostly by reason of incompatibility, a reduction to half of the dose was necessary in six of these patients. The control of plasma fluoride concentration indicated
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Fluoride's Effect on Male Reproductive System -- The "Sprando/Collins" Anomaly
In contrast to the findings of over 60 animal studies from other research teams, a series of studies by FDA researchers Sprando & Collins reported virtually no evidence of reproductive toxicity among animals treated with very high levels of fluoride exposure. The reasons for this discrepancy remains unclear. Excerpts from Sprando/Collins' Studies: "This study
Fluoride's Effect on the Male Reproductive System -- In Vitro Studies
Carefully controlled in vitro studies have found that direct exposure of fluoride to the testes or semen inhibits testosterone production and damages sperm. While researchers have known since the 1930s that mega concentrations of fluoride can completely (but reversibly) immobilize sperm, it was not until the 1970s and 1980s that researchers found that relatively modest concentrations of fluoride could cause damage prior to complete immobilization.
Fluoride's Effect on Male Reproductive System: Animal Studies
Over 60 studies on animals (including rats, mice, roosters, and rabbits) have found that fluoride adversely impacts the male reproductive system. These studies have repeatedly found the following effects: (1) decreases in testosterone levels; (2) reduced sperm motility; (3) altered sperm morphology; (4) reduced sperm quantity; (5) increased oxidative stress; (6) and reduced capacity to breed.
Fluoride's Effect on Male Reproductive System - Human Studies
Consistent with in vitro and animal research, studies of human populations have reported associations between fluoride exposure and damage to the male reproductive system. Most notably, a scientist at the Food & Drug Administration reported in 1994 that populations in the United States with more than 3 ppm fluoride in their water had lower "total fertility rates" than populations with lower fluoride levels.
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