2026: Low-Dose Fluoride and Lead Co-Exposure Alters Bone Mineral Density in Youth

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The study below is further evidence of fluoride effects on thyroid hormone metabolism. BMI is closely tied to thyroid dysfunction.

SEE: Fluoride, Lead & Thyroid: viewtopic.php?f=7&t=3761&p=4450

Li C, Niu Z, Du Y, Yang L, Wu F, Hu X, Meng X, Feng Z, Niu S, Sun Q, Wang Y, Fu X, Zhou G, Yu F, Ba Y - "Low-Dose Fluoride and Lead Co-Exposure Alters Bone Mineral Density in Youth: A Nationally Representative Cross-Sectional Study" Journal of Trace Elements in Medicine and Biology In Press:127889 (2026)
https://doi.org/10.1016/j.jtemb.2026.127889|

Highlights

• Blood levels of fluoride and lead had sex differences, which were higher in boys.

• Lead levels show nonlinear association with lumbar BMD: steep decline then plateau.

• Fluoride exposure exhibited a U-shaped, non-linear relationship with BMD.

• Co-exposure to fluoride and lead exacerbated changes in BMD.

Abstract

Purpose
Both lead and fluoride can accumulate in the skeleton and cause skeletal damage; however, it remains unclear whether their co-exposure exacerbates the impacts on bone tissue. This study aims to investigate the relationship between co-exposure to fluoride and lead and changes in bone mineral density (BMD) among children and adolescents.

Methods
Data were derived from 2378 participants in the National Health and Nutrition Examination Survey (2013-2016). Laboratory professionals measured the concentrations of plasma and water fluoride, whole blood and urine lead, BMD of the lumbar spine, pelvic, left and right legs. Linear regression, interaction and restricted cubic spline models were used to analyze the relationship between fluoride and lead exposure and BMD.

Results
Plasma and water fluoride showed U-shaped associations with BMD, while blood and urinary lead demonstrated inverse nonlinear relationships with lumbar spine BMD—initially steep decline followed by an attenuated decrease (P-overall < 0.05, P-nonlinear < 0.05). Furthermore, the BMD of the pelvis and legs decreased as lead levels increased (P < 0.05). The interaction model of plasma fluoride and blood lead showed that, for every 1-unit increase in the interaction term, the BMD of the lumbar spine, left and right legs decreased by 1.679, 3.104, and 3.068 (P < 0.05), respectively.

Conclusions
This study demonstrates that exposure to fluoride and lead is associated with changes in BMD among youth. Co-exposure to fluoride and lead exacerbates changes in BMD more than single exposure, suggesting synergistic effects on bone impairment.

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In this context, check the latest study by the Tianjin gang:

Zhang D, Wang Y, Li W, Li F, Duan Y, Cui Y - "Association between childhood obesity and thyroid function: a cross-sectional study in a Chinese population" BMC Public Health 26(1):1072 (2026)
https://doi.org/10.1186/s12889-026-26812-8
"Both the restricted cubic spline model and the logistic regression model indicated an association between childhood obesity and subclinical hypothyroidism. With the increase of children’s BMI, the detection rate of subclinical hypothyroidism shows an upward trend."

BMI-z-score exhibited a U-shaped nonlinear correlation with log10-transformed TSH (P for overall association < 0.001, P for nonlinear association = 0.0083).

ALSO:

Alfaifi HH, Altowairgi MA, Algethami RG, Altowairqi AH, Althomali HD, Almalki OM - "Effectiveness of Bariatric Surgery for Improving Thyroid Function and Reducing Levothyroxine Dose in Patients With Obesity and Overt Hypothyroidism" Cureus 15(5):e38780 (2023)
https://doi.org/10.7759/cureus.38780
"Obesity was positively correlated with the levels of FT3, FT4 and TSH."

Dahl M, Ohrt JD, Fonvig CE, Kloppenborg JT, Pedersen O, Hansen T, Holm JC - "Subclinical Hypothyroidism in Danish Lean and Obese Children and Adolescents" J Clin Res Pediatr Endocrinol 9(1):8-16 (2017)
https://doi.org/10.4274/jcrpe.3319
"Obesity is positively correlated with subclinical hypothyroidism."

Dhabhai N, Chowdhury R, Virmani A, Chaudhary R, Taneja S, Mittal P, Dewan R, Dang A, Kaur J, Bhandari N - "Burden, risk factors and outcomes associated with adequately treated hypothyroidism in a population-based cohort of pregnant women from North India" PLoS One 18(9):e0282381 (2023)
https://doi.org/10.1371/journal.pone.0282381
"Obesity is positively correlated with hypothyroidism."

Han C, Li C, Mao J, Wang W, Xie X, Zhou W, Li C - "High Body Mass Index Is an Indicator of Maternal Hypothyroidism, Hypothyroxinemia, and Thyroid-Peroxidase Antibody Positivity during Early Pregnancy" Biomed Res Int 2015:351831 (2015)
https://doi.org/10.1155/2015/351831
"Obesity was positively correlated with TSH levels and negatively correlated with FT4 levels."

Knudsen N, Laurberg P, Rasmussen LB, Bülow I, Perrild H, Ovesen L, Jørgensen T - "Small differences in thyroid function may be important for body mass index and the occurrence of obesity in the population" J Clin Endocrinol Metab 90(7):4019-4024 (2005)
https://doi.org/10.1210/jc.2004-2225
"BMI was positively correlated with TSH levels and negatively correlated with FT4 levels."

Lass N, Barth A, Reinehr T - "Thyroid Volume and Thyroid Function Parameters Are Independently Associated with Weight Status in Overweight Children" Horm Res Paediatr 93(5):279-286 (2020)
https://doi.org/10.1159/000509786
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Mahdavi M, Amouzegar A, Mehran L, Madreseh E, Tohidi M, Azizi F - "Investigating the prevalence of primary thyroid dysfunction in obese and overweight individuals: Tehran Thyroid Study" BMC Endocr Disord 21(1):89 (2021)
https://doi.org/10.1186/s12902-021-00743-4
"Obesity is positively correlated with overt hypothyroidism and TPOAb positivity."

Michalaki MA, Vagenakis AG, Leonardou AS, Argentou MN, Habeos IG, Makri MG, Psyrogiannis AI, Kalfarentzos FE, Kyriazopoulou VE - "Thyroid function in humans with morbid obesity" Thyroid 16(1):73-78 (2006)
https://doi.org/10.1089/thy.2006.16.73
"Obesity was positively correlated with the levels of FT3."

Nayak SS, Hashemi SM, Patel M, Shafi N, Biswas P, Javankiani S, Jaladi P, Patil SB, Rashid R, Amini-Salehi E, Ameen D, Janani KV, Jonnalagadda AK, Agyeman KB - "The impact of weight loss interventions on thyroid function: a systematic review and meta-analysis" Ann Med Surg (Lond) 87(7):4484-4497 (2025)
https://doi.org/10.1097/MS9.0000000000003428
"BMI was positively correlated with FT3 levels and negatively correlated with FT4 levels."

Radetti G, Longhi S, Baiocchi M, Cassar W, Buzi F - "Changes in lifestyle improve body composition, thyroid function, and structure in obese children" J Endocrinol Invest 35(3):281-285 (2012)
https://doi.org/10.3275/7763
"Obesity was positively correlated with the levels of FT3 and TSH."

Räisänen L, Lommi S, Engberg E, Kolho KL, Viljakainen H - "Central obesity in school-aged children increases the likelihood of developing paediatric autoimmune diseases" Pediatr Obes 17(3):e12857 (2022)
https://doi.org/10.1111/ijpo.12857
"Obesity is associated with subclinical hypothyroidism in the presence of thyroid autoantibodies."

Reinehr T, de Sousa G, Andler W - "Hyperthyrotropinemia in obese children is reversible after weight loss and is not related to lipids" J Clin Endocrinol Metab 91(8):3088-3091 (2006)
https://doi.org/10.1210/jc.2006-0095
"Obesity was positively correlated with the levels of FT3 and TSH."

Song RH, Wang B, Yao QM, Li Q, Jia X, Zhang JA - "The Impact of Obesity on Thyroid Autoimmunity and Dysfunction: A Systematic Review and Meta-Analysis" Front Immunol 10:2349 (2019)
https://doi.org/10.3389/fimmu.2019.02349
"Obesity is positively correlated with overt hypothyroidism, subclinical hypothyroidism and TPOAb positivity."

Velluzzi F, Pisanu S, Galletta M, Fosci M, Secci G, Deledda A, Boi F - "Association between High Normal TSH Levels and Obesity in Women with Anti-Thyroid Autoantibodies (ATAs)" J Clin Med 11(17):5125 (2022)
https://doi.org/10.3390/jcm11175125
"Positive correlation between TSH and BMI in obese women with positive anti-thyroid autoantibodies."

Yan Y, Xu M, Wu M, Wang X, Li F, Zhang J, You L, Pan X, Feng W, Wu J, Chen C, Li X, Yan L - "Obesity is associated with subclinical hypothyroidism in the presence of thyroid autoantibodies: a cross-sectional study" BMC Endocr Disord 22(1):94 (2022)
https://doi.org/10.1186/s12902-022-00981-0
"Obesity is positively correlated with subclinical hypothyroidism."