Written by Greg Arnold, DC, CSCS. Case won as exposure to perfluoroalkyl acids found to be linked to a 54% increased risk of hypothyroidism.
The thyroid is a butterfly shaped gland located just above your collarbone in your neck (1). Its’ primary role in health is making hormones that affect metabolism, growth, and development, especially brain maturation and development (2). The thyroid also plays a very important role in nerve growth and function (3), especially in children (4).
Alterations in thyroid function can cause either growth delay or early onset of precocious puberty in both males and females (5), and a significant source in altered thyroid function is thought to be due to pollution exposure (6), especially to chemicals called perfluoroalkyl acids (7). This hypothesis came to a head when a lawsuit filed in 2001 alleged pollution as the cause for many health problems suffered by residents of 2 small Ohio and West Virginia towns due to pollution from a Teflon manufacturing facility in Parkersburg, West Virginia between 1950 and 2004.
Settlement of the lawsuit led to the creation of The C8 Health Project that collected data on 69,030 people (8), of which 10,725 children between and ages of 1 and 17 had blood levels of perfluoroalkyl acid and thyroid hormone measured. The researchers found (9) that those with the highest 25% blood levels of perfluoroalkyl acids had a 54% increased risk of having decreased thyroid function (hypothyroidism) compared to those with the lowest 25% of blood levels (> 38.5 vs < 5.4 nanograms/milliliter, p < 0.05). The 0.4% prevalence of hypothyroidism in the children of the C8 Health Project was several times higher than the 0.04-0.14% prevalence of hypothyroidism in populations not affected by perfluoroalkyl acid exposure (10), further strengthening the data.
For the researchers, “This is the first large-scale report in children suggesting associations of [blood levels of perlfuoroalkyl acids] with thyroid hormone levels…and hypothyroidism” but that “further studies to understand the effect of pre-or postnatal exposure to PFAAs on thyroid hormones in children are warranted.”
Source: Lopez-Espinosa, MJ;Mondal, D; Armstrong, B; Bloom, MS; Fletcher,T (2012) Thyroid Function and Perfluoroalkyl Acids in Children Living Near a Chemical Plant. Environmental health perspectives, 120 (7). pp. 1036-41. ISSN 0091-6765 DOI: 10.1289/ehp.1104370
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Posted June 26, 2014.
References:
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- Rice D, Barone S. Critical periods of vulnerability for the developing nervous system: evidence from humans and animal models. Environ Health Perspect 2000; 108(suppl 3):511–533
- Papi G, Uberti ED, Betterle C, Carani C, Pearce EN, Braverman LE, et al. Subclinical hypothyroidism. Curr Opin Endocrinol Diabetes Obes 2007; 14:197–208.
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- Liu Y, Wang J, Fang X, Zhang H, Dai J. The thyroid-disrupting effects of long-term perfluorononanoate exposure on zebrafish (Danio rerio). Ecotoxicology 2011; 20:47–55
- Frisbee SJ, Brooks AP, Maher A, Flensborg P, Arnold S, Fletcher T, et al. The C8 health project: design, methods, and participants. Environ Health Perspect 2009; 117:1873–1882.
- Lopez-Espinosa LJ. Thyroid Function and Perfluoroalkyl Acids in Children Living Near a Chemical Plant. Environ Health Perspect 2012;120(7):1036-41. doi: 10.1289/ehp.1104370. Epub 2012 Mar 27
- Hunter I, Greene SA, MacDonald TM, Morris AD. Prevalence and aetiology of hypothyroidism in the young. Arch Dis Child 2000; 83:207–210.
