Age-Related Decline of Thyroid Function

​The anti-aging movement got its initial boost after the publication in 1990 in the New England Journal of Medicine of an article by Daniel Rudman, MD, professor of medicine and academic endocrinologist, whose career focused on the aging of the endocrine system and the resulting hormone deficiencies. His landmark article, "Effects of Human Growth Hormone in Men Over 60 Years Old", concluded that "Diminished secretion of growth hormone is responsible in part for the decrease of lean body mass, the expansion of adipose-tissue mass, and the thinning of the skin that occur in old age." (N Engl J Med 1990; 323:1-6.)

It is a well-known fact that hormone production declines with age. (The exceptions are insulin and cortisol, which typically increase with age.)
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The controversy that has arisen is whether health benefit can accrue from supplementation of hormones to maintain them at youthful levels.

​Us "anti-aging" or preventive medicine doctors rely on the increasing scientific evidence that optimizing hormones creates physical well-being. We see prevention of continued decline and even restoration of lost function. Conventional medicine, however, refuses to accept this simple concept.

Mainstream medicine is stuck on the idea that pharmaceuticals are the best answer to life’s woes as we strike middle age. Increasingly alien molecules, totally not found in nature, are somehow going to ease the diabetes, cardiovascular disease, high blood pressure, and other maladies that strike us later in life.

I have a patient who was doing very well on my bio-identical hormone program, who needed to see me, but could not due to distance. His new "provider" asked him why he was taking thyroid. He answered, for age-related decline. She told him that thyroid function does not go down with age.

Huh?!
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​This medical professional is not only stating that taking thyroid will not provide youthful health benefit, but she is saying that thyroid activity simply does not decline with age in the first place!

​Let’s look at the scientific literature.

“Serum TSH concentrations decrease in healthy elderly subjects due to an age-related decrease in TSH secretion by the pituitary.”[1,2,3] So, pituitary gland function declines with age, including production of the hormone (TSH) that stimulates the thyroid to produce more of what the thyroid gland makes, T4. The T4 is inactive, acting as an available store, and accessible for conversion throughout the body into the active form, T3. But, this T4 to T3 conversion occurs less and less efficiently as we age, also.[2]

“After exclusion of.... confounders, most studies show similar results: A clear, age-dependent decline in serum Thyroid Stimulating Hormone (TSH) and (free) T3 ....”[2] In the elderly, “Thyroid hormones levels are usually within the lower part of normal values reported in the general population.”[4] “There is evidence that the decreased thyroid hormone levels observed in aging are due to lower TSH concentrations, and that lower TSH concentrations may be linked to an impaired pituitary activity.”[5] But, as mentioned in the previous paragraph, T4 to T3 conversion is vital as well, with “the net result of this decreased de-iodination with advancing age is a clear, age-dependent decline in total and free T3 levels...”[2]

​However, studies done only in centenarian Ashkenazi Jews, analyzed due to their genetic homogeneity, show a rise of TSH. Certainly we can say that this represents a genetic predisposition to higher levels of TSH that are associated with exceptional longevity. [5] And this rise of TSH in these individuals is not related to a decrease of thyroid hormone.[6]

Bottom line, in most humans, thyroid function declines with age. Exceedingly long-lived individuals do not show a decline of thyroid function.[7]

​Regarding the management of chronic health conditions, the sad reality about the current medical system is this: You get processed, but no benefit. In return for allowing the clinic to update your electronic medical record, and get access to your insurance money, you get a few prescriptions for pharmaceuticals that “manage” your problem. Who is satisfied with all this: the “provider’s” employer, who ends up with liability coverage and profit.

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Bibliography:

1. van Coevorden A, Laurent E, Decoster C, et al, 1989 Decreased basal and stimulated thyrotropin secretion in healthy elderly men. J Clin Endocrinol Metab 69: 177-185.
2. Peeters RP. Thyroid hormones and aging. Hormones (Athens). 2008 Jan-Mar;7(1):28-35. http://www.ncbi.nlm.nih.gov/pubmed/18359742 
3. Mazzoccoli G, et al. Hypothalamus-hypophysis-thyroid axis function in healthy aging. J Biol Regul Homeost Agents 2010, 24: 433–439. http://www.ncbi.nlm.nih.gov/pubmed/21122282
4. Retornaz F, et al. Thyroid in the elderly (Part 1). Rev Med Interne. 2013 Oct;34(10):623-7. http://www.ncbi.nlm.nih.gov/pubmed/23352291
5. Sell MA, et al. Functional central hypothyroidism in the elderly. Aging Clin Exp Res 2008, 20: 207–210.http://www.ncbi.nlm.nih.gov/pubmed/18594187
6. Peeters RP. Thyroid function and longevity: new insights into an old dilemma. J Clin Endocrinol Metab. 2009 Dec;94(12):4658-60. http://press.endocrine.org/doi/full/10.1210/jc.2009-2198
7. Jansen SW, et al. Human longevity is characterised by high thyroid stimulating hormone secretion without altered energy metabolism. Sci Rep. 2015 Jun 19;5:11525. http://www.nature.com/articles/srep11525