Do You Need Preventive Thyroid Treatment?

Treating Antibodies When TSH Is Normal

white pills, levothyroxine, thyroid, hypothyroidism
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Preventive thyroid treatment is a controversial subject. Is there anything you can do to prevent a thyroid condition or keep it from getting worse? If you ask, some endocrinologists will simply dismiss you, or tell you that you have no treatment options. Research findings, however, support the understanding that Hashimoto's thyroiditis—an autoimmune disease that causes hypothyroidism—may, in fact, be preventable, slowed, or even stopped entirely before it progresses to destruction of your thyroid gland and overt hypothyroidism.

In a presentation at the Endocrine Society's Endo 2005 conference, Dr. Ting Chang and his colleagues reported on giving the thyroid hormone replacement drug levothyroxine (common brand names include Synthroid, Levoxyl, and Tirosint) to Hashimoto's thyroiditis patients. These patients had a normal range thyroid stimulating hormone (TSH), and were designated as "euthyroid, meaning that their TSH levels were in the normal range. These patients also, however, had elevated thyroid peroxidase (TPO) antibodies. Elevated TPO levels are indicative of autoimmune Hashimoto's thyroiditis.

Half the patients were given levothyroxine for six months and the other half received no drug treatment. The thyroid function tests and autoantibody titers were measured before and after the 6-month period. The findings were important:

  • Those receiving levothyroxine had substantially decreased autoantibody levels, and the antibody levels actually increased in some among the untreated group.
  • TSH levels decreased in the treated group, averaging 0.5 vs 2.5 in the untreated group.

The researchers concluded that early prophylactic (preventative) levothyroxine treatment might be useful to help slow down the progression of the autoimmunity of Hashimoto's thyroiditis.

This is not the first study to show that preventive treatment can ward off the progression of Hashimoto's or development of overt hypothyroidism. 

In the March 2001 issue of the journal Thyroid, German researchers reported on their study of patients with euthyroid Hashimoto's, half of whom were treated with levothyroxine for a year, the other half untreated. After 1 year, the antibody levels and lymphocytes, which are evidence of inflammation, decreased significantly only in the group receiving the medication. Among the untreated group, antibody levels rose or remained the same.

The researchers concluded that preventative treatment of euthyroid Hashimoto's patients reduced various markers of autoimmune thyroiditis. They also speculated that such treatment might be able to stop the progress of Hashimoto's disease, or perhaps prevent the development of hypothyroidism.

In another study, Japanese researchers found that treatment with levothyroxine can reduce the incidence of Hashimoto's thyroiditis, as well as help alleviate the symptoms of the disease.

In the study of patients with euthyroid Hashimoto's disease, one group of patients received levothyroxine treatment, and the other group did not receive treatment. After 15 months, the treated group had significantly increased free T4 levels, significantly decreased TSH levels, and a reduction in both anti-thyroglobulin antibody (Tg-Ab) and anti-thyroid peroxidase antibody levels. The size of the thyroid glands also decreased in the treated group, while those not receiving treatment had an increase in thyroid size, a marker for inflammation of the gland.

The researchers reported that although levothyroxine treatment is "mandatory in hypothyroid autoimmune thyroiditis patients, the treatment which is shown to inhibit autoimmune process in animal models is still controversial in euthyroid Hashimoto's disease patients where the disease has not destroyed the thyroid gland enough to cause hypothyroidism."

They found, however, that levothyroxine treatment at doses keeping TSH at low-normal levels appears to be effective not only in decreasing the autoantibody levels but also in the goiter size, which could ultimately prevent progression to overt autoimmune hypothyroidism.

A Word from Verywell 

As you can see, there is a significant body of research that demonstrates that preventive treatment with levothyroxine may be warranted in people with euthyroid Hashimoto's disease, who have normal TSH levels but whose antibody levels show evidence of autoimmune Hashimoto's disease. Such treatment can in some cases relieve hypothyroidism symptoms, slow down the elevation of thyroid antibodies, help prevent worsening of autoimmune disease, and prevent the development of hypothyroidism.

If you have thyroid symptoms, a "normal" TSH level, but haven't been tested for thyroid antibodies, insist on having the TPO test done by your practitioner. 

If you have thyroid symptoms, a "normal" TSH level, and elevated thyroid antibodies, consider asking for treatment, and if your physician is unwilling, consider finding a more knowledgeable or open-minded doctor.

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Article Sources
  • En-Ting Chang, Du-An Wu, Dee Pei, Shi-Wen Kuo, Ming-Chen Hsieh. [P2-552] Influence of L-Thyroxine Administration in Patients with Euthyroid Hashimoto's Thyroiditis. Endocrine Society Endo 2005 Abstracts
  • Thyroid, 2001 Mar;11(3):249-55, "One-year prophylactic treatment of euthyroid Hashimoto's thyroiditis patients with levothyroxine: is there a benefit?"
  • Duygu Yazgan Aksoy, et. al. "Effects of Prophylactic Thyroid Hormone Replacement in Euthyroid Hashimoto's Thyroiditis" Endocr J (Japan) Vol. 52: 337-343, (2005).