To assess studies that evaluate the relation between serum thyrotropin concentration, very old subjects, and their events. Our search was restricted to studies involving humans aged 65 years or older, and written in English, Spanish, or Portuguese. Studies that evaluated the association between elevated serum thyrotropin concentration among elderly subjects with subclinical hypothyroidism were chosen since at least in part they included a subpopulation of individuals aged 80 years and above. Thirteen studies were selected. No significant increase in risk of cardiovascular events, coronary heart disease, or total mortality was observed. Elevated thyrotropin concentration was associated with longevity.
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To assess studies that evaluate the relation between serum thyrotropin concentration, very old subjects, and their events. Our search was restricted to studies involving humans aged 65 years or older, and written in English, Spanish, or Portuguese. Studies that evaluated the association between elevated serum thyrotropin concentration among elderly subjects with subclinical hypothyroidism were chosen since at least in part they included a subpopulation of individuals aged 80 years and above.
Thirteen studies were selected. No significant increase in risk of cardiovascular events, coronary heart disease, or total mortality was observed. Elevated thyrotropin concentration was associated with longevity. More randomized controlled trials are required to better define the potential benefits of elevated thyrotropin concentration in this oldest old population, hormone replacement, and longevity. Subclinical hypothyroidism is a laboratory diagnosis 1 defined by an abnormally high serum thyrotropin TSH level associated with a normal plasma concentration of free thyroxin fT4.
Subclinical thyroid dysfunction has been associated with several negative clinical outcomes such as hypercholesterolemia, atherosclerosis, 7 coronary heart disease events and mortality, 2 , 7 cognitive impairment, 2 , 8 , 9 depression, 10 disability, 2 lower physical function, 11 and risk of progression to overt hypothyroidism. Serum TSH concentration increases slightly in very old healthy individuals, 13 regardless of the presence of antithyroid antibodies 5 , 14 and along with an age-dependent decline in serum free and total triiodothyronine T3 , suggesting that some very elderly individuals may have an altered set point of the hypothalamic-pituitary-thyroid axis.
It is possible that the decrease in thyroid function and metabolic rate 11 may be adaptive mechanisms to prevent catabolism and reduce damage to DNA by reactive oxygen species. Despite this evidence, the hypothesis that some degree of physiological decrease in thyroid activity at a tissue level may favor effects in oldest old subjects remains uncertain.
To assess studies that evaluated the relation between elevated serum thyrotropin concentrations in mild hypothyroidism and comorbidities in individuals aged over 80 years. Studies evaluating the association between elevated serum TSH levels among elderly subjects with subclinical hypothyroidism were included, since at least in part, they included a subpopulation of individuals aged 80 years and more.
We excluded studies that lacked this information and studies on non-thyroidal diseases or low-T3 syndrome. Some of these studies did not exclude patients with overt hypothyroidism. We made no restrictions regarding study design or sample size. Our search identified studies Figure 1. The total number of subjects enrolled in the studies varied from 22 to 55, individuals. Two selected studies were multicenter trials.
One was a longitudinal epidemiological study 9 involving six centers in England and Wales evaluating the association between cognitive decline, assessed by the Mini-Mental State Examination MMSE , and high TSH levels in elderly individuals.
Some of the cross-sectional and longitudinal population-based studies recognized that the upper limits of serum TSH levels could have been skewed by individuals with occult autoimmune thyroid dysfunction and negative serum thyroperoxidase antibody aTPO , 14 whereas others considered the results to overestimate thyroid hypofunction since no age-specific range for TSH was adopted, with the possibility of identifying healthy individuals as having subclinical thyroid disease.
Different studies have suggested that the thyroid gland undergoes anatomical and physiological changes with time, providing evidence that its function declines with age. A meta-analysis demonstrated that cardiovascular events and mortality in patients with subclinical hypothyroidism were restricted to those younger than 65 years of age.
It is unclear why inadequately high TSH would be associated with lower mortality 2 and longevity. It is possible that a lower metabolic rate and fluctuating concentration of serum TSH may be represented by early signs of thyroid hypoechogenicity on ultrasound, 27 , 28 decreased fT4, increased rT3, and altered pituitary set point, 14 , 23 as has been documented in centenarians, and could possibly denote adaptive metabolic processes to prevent excessive catabolism.
Elderly patients with subclinical thyroid disease had worse overall results in the MMSE. The association between overt hypothyroidism and cognitive impairment is well established, and there are cases described of secondary dementia due to thyroid dysfunction.
While some studies report worsening of mood with subclinical hypothyroidism, 10 others have not confirmed this association. The studies selected showed no evidence that reduced thyroid function had a positive association with disability 2 or lower physical function.
The literature lacks information on the risks of mildly elevated TSH levels on health both in the general population and in the oldest old individuals. Abnormal concentrations of TSH are often found in these elderly individuals and are associated with a prolonged life span, although the exact mechanism for that remains unclear.
Maybe the use of age-specific reference values could offer a more reliable TSH distribution, more representative of the elderly population. This could be an opportunity to redefine the upper limit of normal for serum TSH, at least for the very elderly population. Current clinical implications and treatment recommendations for oldest old individuals with subclinical hypothyroidism are still unclear. With the gradual expansion of the age group of very old individuals, more randomized controlled trials are required to better define the potential benefits of thyroid hormone replacement for this population.
Treze estudos foram selecionados. Nossa pesquisa identificou estudos Figura 1. National Center for Biotechnology Information , U.
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This article has been cited by other articles in PMC. Abstract To assess studies that evaluate the relation between serum thyrotropin concentration, very old subjects, and their events. Keywords: Hypothyroidism, Aged, 80 and over. OBJECTIVE To assess studies that evaluated the relation between elevated serum thyrotropin concentrations in mild hypothyroidism and comorbidities in individuals aged over 80 years.
Open in a separate window. Figure 1. Chart 1 Studies evaluating the association between subclinical hypothyroidism and the oldest old. Peeters RP.
Thyroid hormones and aging. Hormones Athens ; 7 1 — Thyroid status, disability and cognitive function and survival in old age. Is there a need to redefine the upper normal limit of TSH? Eur J Endocrinol.
The TSH upper reference limit: where are we at? Nat Rev Endocrinol. Age specific distribution of serum thyrotropin and antithyroid antibodies in the US population: implications for the prevalence of subclinical hypothyroidism.
J Clin Endocrinol Metab. Biondi B. Should we treat all subjects with subclinical thyroid disease the same way? Thyroid Studies Collaboration. Subclinical hypothyroidism and the risk of coronary heart disease and mortality. A randomized controlled trial of the effect of thyroxin replacement on cognitive function in community-living elderly subjects with subclinical hypothyroidism: the Birmingham Elderly Thyroid study.
Subclinical hypothyroidism increases the risk for depression in the elderly. Arch Gerontol Geriatr. Thyroid hormone concentrations, disease, physical function and mortality in elderly men.
Biondi B, Cooper DS. The clinical significance of subclinical thyroid dysfunction. Endocr Rev. Thyroid function and longevity: new insights into an old dilemma. Extreme longevity is associated with increased serum thyrotropin. Genetic predisposition to elevated serum thyrotropin is associated with exceptional longevity.
Familial longevity is associated with decreased thyroid function. Age Ageing. Arq Catarinenses Med. Mooradian AD.
Subclinical hypothyroidism in the elderly: to treat or not to treat? Am J Ther. Meta-analysis: subclinical thyroid dysfunction and the risk for coronary heart disease and mortality. Ann Intern Med. The influence of age on relationship between subclinical hypothyroidism and ischemic heart disease: a meta-analysis.
J Clin Endocrinol. Mariotti S. Mild hypothyroidism and ischemic heart disease: is age the answer? Natural history of mild subclinical hypothyroidism: prognostic value of ultrasound. Role of ultrasonography in outcome prediction in subclinical hypothyroid patients treated with levothyroxine.
Endocr J. Thyroid stimulating hormone, cognitive impairment and depression in an older Korean population. Psychiatry Investig. Rev Bras Clin Med. An approach for development of age-, gender-, and ethnicity-specific thyrotropin reference limits.
Arq Bras Endocrinol Metab.
Association between increased serum thyrotropin concentration and the oldest old: what do we know?
Vieira VI. Dosagens de TSH e T 4 simultaneamente. Dosagem inicial de T 4 seguida da dosagem de TSH nas amostras com T 4 abaixo de determinado limite usualmente abaixo do percentil Uma vez localizada a tireoide, a agenesia ou ectopia seriam descartadas. Risk factors for congenital hypothyroidism: an investigation of infant's birth weight, ethnicity, and gender in California, A 7-year experience with low blood TSH cutoff levels for neonatal screening reveals an unsuspected frequency of congenital hypothyroidism CH.
Jose A. Teixeira II ; Lea M. Montenegro Junior V ; Laura S. Ward VI. Como diagnosticar o HSC? Somente pacientes com HSC persistente devem ser considerados para tratamento. No estudo de Huber e cols.
Endocrinologia Hipotireoidismo. Teixeira2, Lea M. Maciel3, Glaucia M. Mazeto4, Mario Vaisman2, Renan M. Montenegro Junior5, Laura S. Although an increasing number of studies have related SCH to an increased risk of coronary artery disease and mortality, there have been no randomized clinical trials verifying the benefit of levothyroxine treatment in reducing these risks, and the treatment remains controversial.