Lithium in drinking water and thyroid function.
BACKGROUND
High concentrations of lithium in drinking water were previously discovered in the Argentinean Andes Mountains. Lithium is used worldwide for treatment of bipolar disorder and treatment-resistant depression. One known side effect is altered thyroid function.


OBJECTIVE
We assessed associations between exposure to lithium from drinking water and other environmental sources and thyroid function.


METHODS
Women (n=202) were recruited in four Andean villages in northern Argentina. Lithium exposure was assessed based on concentrations in spot urine samples, measured by inductively coupled plasma mass spectrometry. Thyroid function was evaluated by plasma free thyroxine (T4) and pituitary gland thyroid-stimulating hormone (TSH), analyzed by routine immunometric methods.


RESULTS
The median urinary lithium concentration was 3,910 μg/L (5th, 95th percentiles, 270 μg/L, 10,400 μg/L). Median plasma concentrations (5th, 95th percentiles) of T4 and TSH were 17 pmol/L (13 pmol/L, 21 pmol/L) and 1.9 mIU/L, (0.68 mIU/L, 4.9 mIU/L), respectively. Urine lithium was inversely associated with T4 [β for a 1,000-μg/L increase=-0.19; 95% confidence interval (CI), -0.31 to -0.068; p=0.002] and positively associated with TSH (β=0.096; 95% CI, 0.033 to 0.16; p=0.003). Both associations persisted after adjustment (for T4, β=-0.17; 95% CI, -0.32 to -0.015; p=0.032; for TSH: β=0.089; 95% CI, 0.024 to 0.15; p=0.007). Urine selenium was positively associated with T4 (adjusted T4 for a 1 μg/L increase: β=0.041; 95% CI, 0.012 to 0.071; p=0.006).


CONCLUSIONS
Exposure to lithium via drinking water and other environmental sources may affect thyroid function, consistent with known side effects of medical treatment with lithium. This stresses the need to screen for lithium in all drinking water sources.
Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden. broberg@med.lu.se
Karin
K
Broberg
Gabriela
G
Concha
Karin
K
Engström
Magnus
M
Lindvall
Margareta
M
Grandér
Marie
M
Vahter
D000328:Adult; D001118:Argentina; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008094:Lithium / Q000652:urine*; D013058:Mass Spectrometry; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014881:Water Supply
D013972:Thyrotropin; D008094:Lithium; D013974:Thyroxine
Ecotoxicol Environ Saf. 2008 Jul;70(3):349-56
18456327
J Lab Clin Med. 1993 Apr;121(4):614-9
8454944
CNS Drugs. 2009;23(3):225-40
19320531
Sci Total Environ. 2009 Jan 15;407(3):1089-96
18990431
Environ Sci Technol. 2010 Sep 1;44(17):6875-80
20701280
Best Pract Res Clin Endocrinol Metab. 2009 Dec;23(6):815-27
19942156
Swiss Med Wkly. 2003 Sep 6;133(35-36):488-90
14652805
Eur J Endocrinol. 2004 May;150(5):605-18
15132715
Br J Psychiatry. 2009 Sep;195(3):271; author reply 271-2
19721127
CNS Drugs. 2009;23(5):397-418
19453201
Best Pract Res Clin Endocrinol Metab. 2009 Dec;23(6):723-33
19942149
J Biol Chem. 2009 Jan 9;284(2):723-7
18757362
Clin Chem. 2007 Nov;53(11):1986-7
17954505
Pediatr Int. 2010 Aug;52(4):631-9
20202157
Br J Psychiatry. 2009 May;194(5):464-5; discussion 446
19407280