Complex alteration of thyroid function in healthy centenarians.

Abstract

Several changes in thyroid function have been described in the elderly and largely attributed to concomitant nonthyroidal illness. The extent to which aging per se contributes to these changes remains to be elucidated, and scanty data are available in extremely old subjects. The present study was designed to focus on thyroid function during physiological aging, taking advantage of two groups of selected aged individuals: group A of healthy centenarians (n = 41; age range, 100-110 yr) and group B including healthy elderly subjects selected by the criteria of the EURAGE SENIEUR protocol (n = 33; age range, 65-80 yr). Control groups included 98 healthy normal adult subjects (group C; age range, 20-64 yr) and 52 patients with miscellaneous nonthyroidal illness (group D; age range, 28-82 yr). Our previous report of a low prevalence of thyroid autoantibodies in centenarians was confirmed and extended by the finding of a similar low autoantibody prevalence in the highly selected healthy elderly population of group B. Subclinical primary hypothyroidism was found in 3 (7.3%) centenarians, and their data were excluded from further statistical evaluation. No significant difference was found in the median serum free T4 levels of groups A-C. Median (and range) serum free T3 (FT3) was lower in centenarians [3.67 pmol/L (2.3-5.5)] than in group B [5.22 pmol/L (3.4-6.1)] and group C [5.38 pmol/L (2.9-8.4); P < 0.0001 vs. both groups]. Similarly, the median serum TSH level of centenarians [0.97 mU/L (< 0.09 to 2.28)] was lower than those in groups B [1.17 mU/L (0.53-2.74)] and C [1.7 mU/L (0.4-4.8); P < 0.0001 vs. both groups]; moreover, serum TSH was also significantly (P < 0.01) lower in group B than in group C. Both serum FT3 and TSH concentrations showed a significant inverse correlation (r = -0.634; P < 0.0001 and r = -0.377; P < 0.0001, respectively) with age. Median serum FT3 in centenarians was lower than that in group D patients [4.61 pmol/L (2.15-6.6); P < 0.0001]. In contrast, median serum rT3 in centenarians [0.40 nmol/L (0.20-0.77)], although higher than those in groups B [0.24 nmol/L (0.15-0.37); P < 0.0001] and C [0.22 nmol/L (0.05-0.46); P < 0.0001], was significantly lower than that in group D [0.60 nmol/L (0.13-2.08); P < 0.0001]. In conclusion, thyroid function appears to be well preserved until the eighth decade of life if healthy subjects are studied, whereas a reduction of serum FT3 is observed in extreme aging.(ABSTRACT TRUNCATED AT 400 WORDS)

Mild Thyroid Deficiency in the Elderly

“…Healthy centenarians showed a lower prevalence of positive anti-thyroid autoantibody titer than elderly controls with a relatively low (7%) prevalence of sHT although the median serum FT3 level was lower than in each other group. Interestingly, median serum TSH level of centenarians was lower than in healthy elderly subjects, in whom however, was significantly lower than in young controls (Mariotti et al, 1993). This study did not resolve the question whether the decreased FT3 and TSH value observed in healthy centenarians, represents an adaptive mechanism to reduced metabolic homeostasis or a protective condition in ageing.…”

“…The relative small number of epidemiological studies with inappropriate statistical power, and the lack of large prospective randomized trials directed to evaluate the therapeutic effect and impact on survival of hormonal therapy in mild thyroid impairment, does not allow to conclude whether mild thyroid impairment is a favorable phenotype or a negative clinical condition, especially in older people. An age-dependent thyroid dysfunction (particularly hypothyroidism) has been well documented in the elderly, including the oldest-old population (>85 yr) (Helfand et al, 2004;Mariotti et al, 1993). An interesting study focused on thyroid function during physiological ageing was carried out by Mariotti et al (1993).…”

“…An age-dependent thyroid dysfunction (particularly hypothyroidism) has been well documented in the elderly, including the oldest-old population (>85 yr) (Helfand et al, 2004;Mariotti et al, 1993). An interesting study focused on thyroid function during physiological ageing was carried out by Mariotti et al (1993). In this study thyroid status was assessed in 41 healthy centenarians and 33 healthy elderly subjects as compared to two control groups: 98 healthy normal adult subjects and 52 patients with miscellaneous non-thyroidal illness.…”

The aging process and function of endocrine glands

“…Thyroid disorders in the elderly are not rare, but they frequently remain undiagnosed because their clinical symptoms are hardly noticeable and frequently changed or masked by concomitant illnesses and medications [23,25]. Acute diseases inhibit the peripheral conversion of T4 reducing the level of T3, at the same time increasing the concentration of the biologically inactive form of T3, so-called reverse triiodothyronine (rT3) [21,26,27,28,29]. Changes in the metabolism of thyroid hormones without diagnosable thyroid diseases are referred to as non-thyroidal illness syndrome (NTIS), euthyroid sick syndrome (ESS) or sick euthyroid syndrome (SES).…”

“…Choroby o ciężkim przebiegu hamują konwersję obwodową T4, zmniejszając stężenie T3 i równocześnie podwyższając stężenie biologicznie nieaktywnej postaci T3, tzw. odwrotnej trijodotyroniny (rT3) [21,25,26,27,28,29]. Zmiany w metabolizmie hormonów tarczycy bez uchwytnych chorób tarczycy określa się mianem non-thyroidal illness syndrome (NTIS), euthyroid sick syndrome (ESS) lub sick euthyroid These syndromes occur in patients with myocardial infarction, sepsis, diabetic coma, following extensive thermal injuries, major surgical procedures and organ transplants.…”