Table 1Genetic, Environmental, and Existential Factors in the Immunopathogeneis of Autoimmune Thyroid Disease
Genetic factors |
Major histocompatibility genes (HLA) |
Immunoregulatory genes (CTLA4, PTPN22, FOXP3, CD25, CD40, FRCL3) |
Thyroid specific genes (TSHR, Tg) |
Environmental factors |
Iodine intake |
Smoking |
Alcohol |
Selenium |
Vitamin D |
Infections |
Stress |
Drugs (estrogens) |
Existential factors |
Female sex |
Parity |
Age |
Table 2The Predictive THEA Score to Estimate the Risk on Developing Overt Autoimmune Hyperthyroidism or Hypothyroidism in the Next 5 Years
Variable |
Score |
TSH, mU/L |
|
<0.4 |
2 |
0.4-2.0 |
0 |
2.1-4.0 |
2 |
4.1-5.7 |
4 |
>5.7 |
6 |
TPO-Ab, kU/L |
|
<100 |
0 |
100-1,000 |
4 |
1,001-10,000 |
6 |
>10,000 |
12 |
Family members |
|
2 Members Graves |
1 |
2 Members Hashimoto |
3 |
Maximal score |
21 |
THEA score, observed/expected event, % |
|
0-7 Low |
2.7/2.6 |
8-10 Medium |
14.6/13.1 |
11-15 High |
27.1/32.9 |
16-21 Very high |
76.9/59.4 |
Table 3Effect of Selenium Supplementation on TPO antibodies in Eight Randomized Clinical Trials
Study |
Selenium preparation |
Outcome TPO-Ab |
On L-T4 |
No. of patients, placebo/selenium |
Baseline Se, µg/L |
Baseline TPO-Ab, kU/L |
Gartner et al. (2002) [23] |
Selenite |
Fall |
Yes |
34/36 |
69 |
904 |
Duntas et al. (2003) [24] |
SeMet |
Fall |
Yes |
31/34 |
75 |
1,875 |
Turker et al. (2006) [25] |
SeMet |
Fall |
Yes |
40/48 |
- |
803 |
Karanikas et al. (2008) [26] |
Selenite |
No change |
Yes |
18/18 |
75 |
524 |
Nacamulli et al. (2010) [27] |
Selenite |
No changea
|
No |
30/46 |
- |
172 |
Eskes et al. (2014) [28] |
Selenite |
No change |
No |
30/31 |
74 |
1,508 |
Pilli et al. (2015) [29] |
SeMet |
No change |
No |
20/40 |
82 |
409 |
de Farias et al. (2015) [30] |
SeMet |
Fall |
Yes |
27/28 |
37 |
1,009 |
Table 4Low Selenium Intake Is Associated with High Prevalence of Hashimoto Thyroiditis: A Population-Based Study in China
Variable |
County with adequate Se intake (n=3,038) |
County with low Se intake (n=3,114) |
P value |
Serum Se, µg/L, median (IQR) |
104 (80-136) |
57 (39-82) |
<0.05 |
Hypothyroidism, % |
2.0 |
4.2 |
<0.001 |
Subclinical hypothyroidism, % |
11.7 |
21.4 |
<0.001 |
Autoimmune thyroid, % |
2.2 |
3.4 |
0.007 |
Subclinical hyperthyroidism, % |
1.3 |
0.6 |
0.003 |
Hyperthyroidism, % |
1.3 |
1.7 |
NS |
Graves disease, % |
0.5 |
0.7 |
NS |
Enlarged thyroid, % |
7.7 |
12.3 |
0.001 |
Nodules, % |
7.6 |
7.2 |
NS |
Table 5Modulation of Exposure to Environmental Factors in Order to Decrease the Risk of Developing Autoimmune Thyroid Disease
Preventive intervention |
Risk of TPO-Ab |
Risk of Hashimoto hypothyroidism |
Risk of Graves hyperthyroidism |
Stop smoking |
Increase |
Increase |
Decrease |
Use alcohol |
No change |
Decrease |
Decrease |
Use selenium |
? |
? |
? |
Use vitamin D |
? |
? |
? |
Avoid pregnancy |
Decrease |
Decrease |
Decease |
Avoid stress |
No change |
No change |
Decrease |