Comparison of Thyroid Function in Lead Poisoned Patients and Healthy Individuals in North India
DOI:
https://doi.org/10.55489/njcm.160720255585Keywords:
Lead poisoning, Thyroid hormones, fT4, TSH, Environmental exposure, Endocrine disruption, North IndiaAbstract
Background: Lead remains a pervasive environmental toxicant in India, with emerging evidence linking it to endocrine disruption. Its potential effect on thyroid function remains unclear, with inconsistent findings across studies. This study aimed to evaluate the association between blood lead concentration (BLC) and thyroid hormone levels in a North Indian population.
Methods: This retrospective study included 237 patients from Punjab who underwent simultaneous testing for BLC and thyroid hormones between January 2022 and December 2023. Patients were grouped by BLC (<10, 10–25, >25 µg/dL), and those with known thyroid disease or on thyroid-altering medications were excluded. BLC and thyroid hormones (fT3, fT4, TSH) were measured using validated instruments (LeadCare II, Roche Elecsys).
Results: Group 3 (BLC >25 µg/dL) had significantly higher fT4 levels (19.26 ± 4.95 pmol/L) and lower TSH levels (2.19 ± 1.77 µIU/L) compared to Group 1 (fT4: 16.26 ± 6.65 pmol/L; TSH: 3.60 ± 4.59 µIU/L; p <0.05). No statistically significant differences were observed in fT3 values between the groups (p = 0.513). Regression analysis showed a positive association between BLC and fT4 and a negative association with TSH. These findings suggest a trend toward subclinical hyperthyroid features in individuals with elevated lead levels.
Conclusion: Elevated BLC is associated with altered thyroid function, notably increased fT4 and decreased TSH concentrations, even in the absence of overt thyroid disease. These results support lead’s role as a potential endocrine disruptor, with possible involvement of oxidative stress and neuroendocrine pathways.
References
Wani AL, Ara A, Usmani JA. Lead toxicity: a review. Interdiscip Toxicol. 2015 Jun 1;8(2):55-64. Doi: https://doi.org/10.1515/intox-2015-0009 PMid:27486361 PMCid:PMC4961898
Nakhaee S, Rezayee M, Mansouri B, et al. Comparison of Thyroid Function in Lead-Poisoned Patients and Healthy Individuals in Eastern Iran. Biol Trace Elem Res. 2022 Jul 1;200(7):3097-102. Doi: https://doi.org/10.1007/s12011-021-02935-4 PMid:34599429
World Health Organization. Guideline for clinical management of exposure to lead. Geneva: WHO; 2021 [cited 2025 March 2]. Available from: https://www.who.int/publications/i/item/9789240037045.
Centers for Disease Control and Prevention. CDC Updates Blood Lead Reference Value. Atlanta: CDC; 2024 [cited 2025 March 2]. Available from: https://www.cdc.gov/lead-prevention/php/news-features/updates-blood-lead-reference-value.html
Roy S, Dietrich KN, Gomez HF, et al. Considering Some Negative Implications of an Ever-Decreasing U.S. Centers for Disease Control and Prevention (CDC) Blood Lead Threshold and "No Safe Level" Health Messaging. Environ Sci Technol. 2023;57(35):p. 12935-9. Doi: https://doi.org/10.1021/acs.est.3c04766 PMid:37611243
Rousseau MC, Straif K, Siemiatycki J. IARC Carcinogen Update. Environ Health Perspect. 2005 Sep;113(9):A580-1. Doi: https://doi.org/10.1289/ehp.113-1280416 PMid:16140603
Rahimpour F, Abdollahi O, Rafeemanesh E, et al. Evaluation the effect of serum lead levels on thyroid function in battery industry workers. Indian J Occup Environ Med. 2023;27(2):120-5. Doi: https://doi.org/10.4103/ijoem.ijoem_64_22 PMid:37600642 PMCid:PMC10434806
Armstrong M, Asuka E, Fingeret A. Physiology, Thyroid Function. [Updated 2023 Mar 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537039/
Nussey S, Whitehead S. Chapter 3, The thyroid gland. In: Endocrinology: An Integrated Approach [Internet]. Oxford: BIOS Scientific Publishers; 2001 [cited 2025 Jan 3]. Doi: https://doi.org/10.1201/b15306
Kim HC, Jang TW, Chae HJ, et al. Evaluation and management of lead exposure. Ann Occup Environ Med. 2015 Dec 15;27(1):30. Doi: https://doi.org/10.1186/s40557-015-0085-9 PMid:26677413 PMCid:PMC4681084
Jurdziak M, Gać P, Poręba M, et al. Concentration of Thyrotropic Hormone in Persons Occupationally Exposed to Lead, Cadmium and Arsenic. Biol Trace Elem Res. 2018 Apr 19;182(2):196-203. Doi: https://doi.org/10.1007/s12011-017-1096-x PMid:28726072 PMCid:PMC5838128
Gharaibeh MY, Alzoubi KH, Khabour OF, et al. Lead exposure among five distinct occupational groups: a comparative study. Pak J Pharm Sci. 2014 Jan;27(1):39-43.
Memon NS, Kazi TG, Afridi HI, et al. Evaluation of calcium and lead interaction, in addition to their impact on thyroid functions in hyper and hypothyroid patients. Environmental Science and Pollution Research. 2016 Jan 8;23(1):878-86. Doi: https://doi.org/10.1007/s11356-015-5325-6 PMid:26347420
Stojsavljević A, Rovčanin B, Krstić Đ, et al. Evaluation of trace metals in thyroid tissues: Comparative analysis with benign and malignant thyroid diseases. Ecotoxicol Environ Saf. 2019 Nov 15;183:109479. Doi: https://doi.org/10.1016/j.ecoenv.2019.109479 PMid:31365889
Hanif S, Ilyas A, Shah MH. Statistical Evaluation of Trace Metals, TSH and T4 in Blood Serum of Thyroid Disease Patients in Comparison with Controls. Biol Trace Elem Res. 2018 May 23;183(1):58-70. Doi: https://doi.org/10.1007/s12011-017-1137-5 PMid:28836155
Dundar B, Öktem F, Arslan MK, et al. The effect of long-term low-dose lead exposure on thyroid function in adolescents. Environ Res. 2006 May;101(1):140-5. Doi: https://doi.org/10.1016/j.envres.2005.10.002 PMid:16360141
Erfurth EM, Gerhardsson L, Nilsson A, et al. Effects of lead on the endocrine system in lead smelter workers. Arch Environ Health. 2001;56(5):449-55. Doi: https://doi.org/10.1080/00039890109604481 PMid:11777027
Mahajan RK, Walia TPS, Sumanjit. Stripping Voltammetric Determination of Zinc, Cadmium, Lead and Copper in Blood Samples of Children aged between 3 months and 6 years. Online J Health Allied Sci.2005;4(1):1-8.
Chaudhary S, Firdaus U, Ali SM, et al. Factors Associated With Elevated Blood Lead Levels in Children. Indian Pediatr. 2018 Jan 15;55(1):38-40. Doi: https://doi.org/10.1007/s13312-018-1225-4 PMid:28952456
Sharma RK, Agrawal M, Marshall F. Heavy metal contamination of soil and vegetables in suburban areas of Varanasi, India. Ecotoxicol Environ Saf. 2007 Feb;66(2):258-66. Doi: https://doi.org/10.1016/j.ecoenv.2005.11.007 PMid:16466660
Centers for Disease Control and Prevention (CDC). Very high blood lead levels among adults - United States, 2002-2011. MMWR Morb Mortal Wkly Rep. 2013 Nov 29;62(47):967-71.
World Health Organization. Brief guide to analytical methods for measuring lead in blood. 2nd ed. Geneva: WHO; 2020 [cited 2025 March 2]. Available from: https://iris.who.int/bitstream/handle/10665/333914/9789240009776-eng.pdf?sequence=1&isAllowed=y
Sharma S, Mitra P, Bhardwaj P, et al. Blood lead level in school going children of Jodhpur, Rajasthan, India. Turkish Journal of Biochemistry. 2021 Sep 6;46(4):393-8. Doi: https://doi.org/10.1515/tjb-2020-0418
Meridian Bioscience. Product Support. 2025 [cited 2025 April 3]. Available from: https://www.magellandx.com/leadcare-products/leadcare-ii/support/product-literature/
Roche Diagnostics International Ltd. Reference Intervals for Children and Adults Elecsys ® Thyroid Tests hCT cobas e analyzers. CH-6343 Rotkreuz, Switzerland; 2020 [cited 2025 April 3]. Available from: http://life.uni-leipzig.de
Pekcici R, Kavlakoğlu B, Yilmaz S, et al. Effects of lead on thyroid functions in lead-exposed workers. Cent Eur J Med. 2010;5(2):215-8. Doi: https://doi.org/10.2478/s11536-009-0092-8
Kassy C, Meka I, Okwor C, et al. Effects of lead exposure on biomarkers of thyroid and renal function tests among panel beaters in Enugu Metropolis, Nigeria. Niger J Clin Pract. 2022;25(9):1593-9. Doi: https://doi.org/10.4103/njcp.njcp_1845_21 PMid:36149224
Rivera-Buse JE, Patajalo-Villalta SJ, Donadi EA, et al. Impact of lead exposure on the thyroid glands of individuals living in high- or low-lead exposure areas. Medicine (United States). 2023 Mar 24;102(12):E33292. Doi: https://doi.org/10.1097/MD.0000000000033292 PMid:36961188 PMCid:PMC10036069
Nouri S, Zoghi A, Sharif MR, et al. Evaluation of thyroid hormones in patients with lead poisoning. Tehran University of Medical Sciences Journal [Internet]. 2018 Oct 10 [cited 2024 Sep 20];76(7):477-83.
Dursun N, Tutus A. Chronic occupational lead exposure and thyroid function. J Trace Elem Exp Med. 1999;12(1):45-9. Doi: https://doi.org/10.1002/(SICI)1520-670X(1999)12:1<45::AID-JTRA5>3.0.CO;2-D
Meeker JD, Rossano MG, Protas B, et al. Multiple metals predict prolactin and thyrotropin (TSH) levels in men. Environ Res. 2009 Oct;109(7):869-73. Doi: https://doi.org/10.1016/j.envres.2009.06.004 PMid:19595304 PMCid:PMC2743774
Choi JY, Huh DA, Moon KW. Association between blood lead levels and metabolic syndrome considering the effect of thyroid-stimulating hormone based on the 2013 Korea National Health and Nutrition Examination Survey. PLoS ONE. 2020;15(12):e0244821. Doi: https://doi.org/10.1371/journal.pone.0244821 PMid:33382832 PMCid:PMC7775085
Singh B, Chandran V, Bandhu HK, et al. Impact of lead exposure on pituitary-thyroid axis in humans. BioMetals. 2000;13(2):187-92. Doi: https://doi.org/10.1023/A:1009201426184 PMid:11016408
Sherif MM, Mohammed YS, Zedan HAEM. Toxic Effect of Some Heavy Metals (Cadmium and Lead) on Thyroid Function. Egypt J Hosp Med. 2017 Oct;69(5):2512-5. Doi: https://doi.org/10.12816/0041703
Krieg EF. A meta-analysis of studies investigating the effects of occupational lead exposure on thyroid hormones. Am J Ind Med. 2016;59(7):583-90. Doi: https://doi.org/10.1002/ajim.22591 PMid:27094769 PMCid:PMC4934017
Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol. 2015 Apr;3(4):286-95. Doi: https://doi.org/10.1016/S2213-8587(14)70225-6 PMid:25591468
Gaitonde DY, Rowley KD, Sweeney LB. Hypothyroidism: an update. Am Fam Physician. 2012 Aug 1;86(3):244-51.
Liu D, Shi Q, Liu C, et al. Effects of Endocrine-Disrupting Heavy Metals on Human Health. Toxics. 2023 Mar 29;11(4):322. Doi: https://doi.org/10.3390/toxics11040322 PMid:37112549 PMCid:PMC10147072
Slingerland DW. The influence of various factors on the uptake of iodine by the thyroid. J Clin Endocrinol Metab. 1955 Jan;15(1):131-41. Doi: https://doi.org/10.1210/jcem-15-1-131 PMid:13221634
Sandstead HH, Stant EG, Brill AB, et al. Lead intoxication and the thyroid. Arch Intern Med. 1969 Jun;123(6):632-5. Doi: https://doi.org/10.1001/archinte.1969.00300160022004 PMid:5771052
Tuppurainen M, Wagar G, Kurppa K, et al. Thyroid function as assessed by routine laboratory tests of workers with long-term lead exposure. Scand J Work Environ Health. 1988 Jun;14(3):175-80. Doi: https://doi.org/10.5271/sjweh.1934 PMid:3393853
Devi CB, Reddy GH, Prasanthi RPJ, et al. Developmental lead exposure alters mitochondrial monoamine oxidase and synaptosomal catecholamine levels in rat brain. International Journal of Developmental Neuroscience. 2005 Jun 2;23(4):375-81. Doi: https://doi.org/10.1016/j.ijdevneu.2004.11.003 PMid:15927761
Goldman RH, White R, Kales SN, et al. Lead poisoning from mobilization of bone stores during thyrotoxicosis. Am J Ind Med. 1994 Mar 19;25(3):417-24. Doi: https://doi.org/10.1002/ajim.4700250309 PMid:8160659
Demontiero O, Vidal C, Duque G. Aging and bone loss: new insights for the clinician. Ther Adv Musculoskelet Dis. 2012 Apr 14;4(2):61-76. Doi: https://doi.org/10.1177/1759720X11430858 PMid:22870496 PMCid:PMC3383520
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