Subclinical Thyroid Dysfunction and Frailty Among Older Men

Biomarkers of frailty

Several biomarkers have been proposed to identify frailty, a multisystemic age-related syndrome. However, the complex pathophysiology and the absence of a consensus on a comprehensive and universal definition make it challenging to pinpoint a singular biomarker or set of biomarkers that conclusively characterize frailty. This review delves into the main laboratory biomarkers, placing special emphasis on those associated with various pathways closely tied to the frailty condition, such as inflammation, oxidative stress, mitochondrial dysfunction, metabolic and endocrine alterations and microRNA. Additionally, we provide a summary of different clinical biomarkers encompassing different tools that have been proposed to assess frailty. We further address various imaging biomarkers such as Dual Energy X-ray Absorptiometry, Bioelectrical Impedance analysis, Computed Tomography and Magnetic Resonance Imaging, Ultrasound and D3 Creatine dilution. Intervention to treat frailty, including non-pharmacological ones, especially those involving physical exercise and nutrition, and pharmacological interventions, that include those targeting specific mechanisms such as myostatin inhibitors, insulin sensitizer metformin and with special relevance for hormonal treatments are mentioned. We further address the levels of different biomarkers in monitoring the potential positive effects of some of these interventions. Despite the availability of numerous biomarkers, their performance and usefulness in the clinical arena are far from being satisfactory. Considering the multicausality of frailty, there is an increasing need to assess the role of sets of biomarkers and the combination between laboratory, clinical and image biomarkers, in terms of sensitivity, specificity and predictive values for the diagnosis and prognosis of the different outcomes of frailty to improve detection and monitoring of older people with frailty or at risk of developing it, being this a need in the everyday clinical practice.

Correlation of subclinical hypothyroidism with sarcopenia and its components in the Chinese older adults

OBJECTIVE

To identify the correlation of thyroid function and subclinical hypothyroidism (SCH) with sarcopenia and its components in the older Chinese adults.

METHODS

Older adults were recruited and divided into SCH group and non-SCH group. Free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were measured by electrochemiluminescence. Appendicular skeletal muscle mass (ASM) was measured, and skeletal muscle index (SMI) was further calculated. Grip strength was measured. Physical performance was graded by the Short Physical Performance Battery (SPPB) scores of the gait speed test, chair stand test and balance test.

RESULTS

Of the 240 older adults included, 48 (20.00%) presented with SCH. The prevalence of sarcopenia in SCH group was higher than that in non-SCH group (33.33% v.s. 18.75%). Grip strength was significantly lower in patients with SCH than those without sarcopenia. In terms of physical performance, 6-meter gait speed and SPPB score were lower in subjects with SCH than those without SCH, while 5 sit-to-stand movements was longer score in subjects with SCH than those without SCH. SCH was significantly correlated with sarcopenia, while FT3, FT4, and TSH levels were not. SCH was significantly correlated with low muscle strength and low muscle mass, but not with low physical performance. FT3 level was positively correlated with grip strength and SMI. TSH level was negatively correlated with grip strength, 6-meter gait speed, and SPPB score, but positively correlated with the time of 5 sit-to-stand movements.

CONCLUSION

SCH is a risk factor for sarcopenia in the older adults and correlated with low muscle strength and low muscle mass, but not with low physical performance. FT3, FT4 and TSH levels are associated with sarcopenia components, but not with sarcopenia.

Exploring the Association between Thyroid Function and Frailty: Insights from Representative Korean Data

BACKGRUOUND

This study investigates the association between thyroid function and frailty in the old patients using representative data.

METHODS

The study was conducted using data from the Korea National Health and Nutrition Examination Survey conducted from 2013 to 2015. The study population included 2,416 participants aged 50 years and older with available thyroid function test data. Frailty assessment was performed using the Fried frailty phenotype. The prevalence of frailty was analyzed across different thyroid diseases and thyroid function parameters.

RESULTS

The significant association between thyroid dysfunction and frailty was observed in overt hyperthyroidism and subclinical hyperthyroidism. After adjusting for various factors, the association between thyroid dysfunction and frailty remained significant. On the other hand, overt hypothyroidism did not show a significant association with frailty in the adjusted analysis. For individuals with overt hyperthyroidism and subclinical hyperthyroidism, higher levels of free thyroxine (FT4) were significantly associated with an increased risk of frailty (aOR >999; 95% CI, >999 to 999). Among individuals with overt hypothyroidism, lower level of FT4 levels and high thyrotropin (TSH) levels showed a significant association with frailty risk (FT4: aOR, <0.01; TSH: aOR, 999). In participants with subclinical hypothyroidism, there were no significant associations between parameters for thyroid and frailty risk.

CONCLUSION

These findings suggest that thyroid dysfunction, particularly overt hyperthyroidism and subclinical hyperthyroidism, may be associated with an increased risk of frailty in the old patients.

Management of thyroid dysfunction and thyroid nodules in the ageing patient

Thyroid dysfunction is a common endocrine disorder in the general population, with a reported prevalence of 10-15%. However, this rate is even higher in older adults, with an estimated prevalence of ≈25% in some populations. Since elderly patients usually present more comorbidities than younger individuals, thyroid dysfunction may carry a synergistic negative health impact, mainly due to increased cardiovascular disease risk. Moreover, thyroid dysfunction in the elderly can be more difficult to diagnose due to its subtle or even asymptomatic clinical presentation, and the interpretation of thyroid function tests may be affected by drugs that interfere with thyroid function or by the coexistence of several diseases. On the other hand, thyroid nodules are also a prevalent condition in older adults, and its incidence increases with age. The assessment and management of thyroid nodules in the ageing patient should take into account several factors, as risk stratification, thyroid cancer biology, patient´s overall health, comorbidities, treatment preferences, and goals of care. In this review article, we summarize the current knowledge on the pathophysiology, diagnosis, and therapeutic management of thyroid dysfunction in elderly patients and we also review how to identify and manage thyroid nodules in this population.

Relationship between Euthyroidism and Muscle Mass and Strength: A Systematic Review

Thyroid hormones play a crucial role in skeletal muscle development, suggesting that thyroid function may influence muscle mass and muscle strength, which are both fundamental health-related indicators of several age-related consequences. However, whether there is a relationship between thyroid hormones, muscle mass, and muscle strength in individuals without thyroid dysfunctions is still unknown. Therefore, this systematic review aims to investigate whether thyroid hormones are related to muscle mass and strength parameters in euthyroid individuals. Three databases were searched (PubMed, Scopus, Web of Science) up to February 14, 2022, for peer-reviewed papers published in English. The search results were conducted independently by two different reviewers. The review included 13 studies with a total of 241,044 participants. All studies were observational: twelve studies measured thyroid stimulating hormone, ten and thirteen studies measured free triiodothyronine and free thyroxine, four studies analyzed the thyroid hormone ratio. The assessment methods for muscle mass were computed tomography, dual-energy X-ray absorptiometry and bioimpedance analysis, whereas hand dynamometer for muscle strength. Low levels within the normal range of free triiodothyronine, high levels within the normal range of free thyroxine, and lower thyroid hormone ratio may contribute to a reduced muscle function, which seems more evident in older males.

A protocol for randomized controlled trial on multidisciplinary interventions for mobility limitation in the older adults (M-MobiLE)

BACKGROUND

Mobility limitation-the loss of exercise capacity or independent living ability-is a common geriatric syndrome in older adults. As a potentially reversible precursor to disability, mobility limitation is influenced by various factors. Moreover, its complex physiological mechanism hinders good therapeutic outcomes with a single-factor intervention. Most hospitals have not incorporated the diagnosis and evaluation of mobility limitation into medical routines nor developed a multidisciplinary team (MDT) treatment plan. We aim to conduct a clinical trial titled "A Multidisciplinary-team approach for management of Mobility Limitation in Elderly (M-MobiLE)" to explore the effect of the MDT decision-making intervention for mobility limitation.

METHODS

The M-MobiLE study will be a multicenter, randomized, and controlled trial. We will recruit a minimum of 66 older inpatients with mobility limitation from at least five hospitals. Older patients with mobility limitation admitted to the geriatrics department will be included. Short-Physical Performance Battery (SPPB), Activities of Daily Living (ADL), Function Impairment Screening Tool (FIST), Geriatric Depression Scale (GDS-15), Short Form - 12 (SF-12), Fried frailty phenotype, social frailty, Morse Fall Risk Scale, SARC-CalF, Mini-Mental State Examination (MMSE), Mini-Nutritional Assessment Short-Form (MNA-SF), and intrinsic capacity will be assessed. The intervention group will receive an exercise-centered individualized MDT treatment, including exercise, educational, nutritional, medical, and comorbidity interventions; the control group will receive standard medical treatment. The primary outcome is the change in the SPPB score, and the secondary outcomes include increased SF-12, ADL, FIST, MMSE, MNA-SF, and intrinsic capacity scores and decreased GDS-15 and SARC-CalF scores.

CONCLUSION

Our results will help develop a multidisciplinary decision-making clinical pathway for inpatients with mobility limitation, which can be used to identify patients with mobility limitation more effectively, improve mobility, and reduce the risk of falls, frailty, and death in older inpatients. The implementation of this MDT strategy may standardize the treatment of mobility limitation, reduce adverse prognosis, and improve quality of life.

TRIAL REGISTRATION

ChiCTR, ChiCTR2200056756, Registered 19 February 2022.

Subclinical hypothyroidism is not associated with femoral osteoporosis in individuals aged 50 years or older

BACKGROUND

Thyroid dysfunction and osteoporosis are conditions strongly associated with aging, and the prevalence of both conditions is expected to increase in the coming decades. Thyroid hormones regulate bone metabolism, and the role of subclinical hypothyroidism on bone mineral density (BMD) is still controversial. Hence, this study aims to assess the association of subclinical hypothyroidism with femoral osteopenia and osteoporosis in individuals aged 50 years or older.

METHODOLOGY

This retrospective cohort study was carried out with 864 outpatients having at least one result for TSH levels before the first record of dual-energy X-ray absorptiometry (DXA). The primary endpoints were osteopenia (-2.5 standard deviation (SD) <T-score <-1.0SD) and osteoporosis (T-score ≤-2.5SD). Cox proportional hazards regression assessed the association of subclinical hypothyroidism (TSH ≥4.5 mIU/L) with osteopenia and osteoporosis in unadjusted and covariate-adjusted models. Hazard ratios (HR) and 95% confidence intervals (95%CI) were calculated, and p-values <0.05 were considered statistically significant.

RESULTS

There was no significant association between subclinical hypothyroidism and femoral osteopenia in either unadjusted [HR: 1.149 (0.835-1.580); p=0.394] or fully covariate-adjusted models [HR: 1.069 (0.774-1.477); p=0.687]. Subclinical hypothyroidism was associated with femoral osteoporosis in the unadjusted analysis [HR: 1.981 (1.044-3.757); p= 0.036], but a lack of association occurred and remained after successive covariate-adjustments analyses [HR: 1.392 (0.615-3.152); p=0.428].

CONCLUSION

Subclinical hypothyroidism is not independently associated with either femoral osteopenia or osteoporosis in individuals aged 50 years or older over a four-year follow-up time.

Association between thyroid hormone levels and frailty in the community-dwelling oldest-old: a cross-sectional study

BACKGROUND

Changes in thyroid hormone levels are commonly recognized characters among the elderly, which were reported to potentially influence incident frailty. Therefore, we examined the cross-sectional associations of thyroid hormones (THs) with frailty as well as the five components characterizing frailty (fatigue, resistance, ambulation, number of illnesses, and loss of weight) among the oldest-old.

METHODS

Four hundred and eighty-seven community-dwelling oldest-old from a local community in Haidian District, Beijing, participated in our recruitment campaign between April 2019 and May 2020. The primary outcomes were a definitive diagnosis of frailty according to the FRAIL scale (Fatigue, Resistance, Ambulation, Illnesses, Loss of weight) and a positive score for each frailty subdomain. Demographic information (age, sex, marital status, and educational status), comorbidities, and details on the participants' lifestyles were recorded. Serum THs including free triiodothyronin (fT3), triiodothyronine (T3), free thyroxine (fT4), and thyroxine (T4) and thyroid stimulating hormone (TSH) levels were also measured at the beginning of our study. Logistic regressions were conducted to screen for potential risk factors for frailty and its subdomains.

RESULTS

Among the total 487 subjects at enrollment, 60 (12.23%) of them were diagnosed with subclinical hypothyroidism and 110 (22.59%) of the total population scored positive for frailty. Logistic regression analyses adjusted for all potential confounders, showed that frailty was significantly associated with the serum TSH concentration (odds ratio [OR]: 1.06), fT3 concentration (OR: 0.54), and subclinical hypothyroidism score (OR: 2.18). The association between fT4 and frailty was absent in our observational study. The fT3/fT4 ratio characterizing peripheral hormone conversion was also tested to be correlated with frailty.

CONCLUSION

Subclinical hypothyroidism, higher TSH level, lower fT3 level, and decreased fT3/fT4 ratio were all associated with frailty assessed by the FRAIL scale among the community-dwelling oldest-old, suggesting a relevant role of thyroid function in aging. Future longitudinal studies are warranted to determine the casual relationship between thyroid dysfunction and frailty in the oldest-old.

Subclinical hypothyroidism in older individuals

Subclinical hypothyroidism, which is defined as a thyroid-stimulating hormone concentration higher than the reference range (generally 4·5 mIU/L or higher) with normal free thyroxine concentrations, is frequently found in older individuals. International guidelines differ in recommendations for management of subclinical hypothyroidism in older individuals. We assessed published data during the past decade on the clinical significance and treatment of subclinical hypothyroidism in individuals aged 65 years and older. Meta-analyses, randomised clinical trials, and cohort studies are discussed in this narrative Review. Studies showed no significantly increased incidence in adverse cardiovascular, musculoskeletal, or cognitive outcomes in individuals aged 65 years or older when serum thyroid-stimulating hormone concentration was 4·5-7·0 mIU/L versus a euthyroid group. Moreover, in older individuals with subclinical hypothyroidism, symptoms of hypothyroidism and cardiac and bone parameters did not improve after levothyroxine treatment. These data suggest that treatment with levothyroxine should be considered for individuals aged 65 years or older with subclinical hypothyroidism when thyroid-stimulating hormone concentration is persistently 7 mIU/L or higher and to not initiate treatment with thyroid-stimulating hormone concentrations of less than 7 mIU/L. Levothyroxine doses should be personalised according to age, comorbidities, and life expectancy.

Association of subtle alterations in thyroid function with presarcopenia in patients with type 2 diabetes mellitus

Aims/Introduction

To investigate the association of subtle alterations in thyroid function with presarcopenia among patients with type 2 diabetes mellitus.

Materials and Methods

A total of 1,865 adult patients with type 2 diabetes mellitus were enrolled in this cross‐sectional study, excluding patients with overt thyroid dysfunction. Skeletal muscle mass measured by dual energy X‐ray absorptiometry was used to assess presarcopenia. Logistic regression models were used to estimate the effects of thyroid hormones on presarcopenia, and subgroup analyses were carried out in different strata of age, sex and body mass index, respectively.

Results

Compared with the euthyroid group (Euthy), the subclinical hyperthyroidism group had an increased odds of presarcopenia (multivariate‐adjusted odds ratio 1.99, 95% confidence interval 1.09–3.63), but the subclinical hypothyroidism group did not (P > 0.05). In the subclinical hyperthyroidism group, age and body mass index <24 kg/m² were independent risk factors for presarcopenia. In the overall Euthy group, an increased odds of presarcopenia was correlated with the elevated free thyroxine : free triiodothyronine ratio (all P for trend <0.05), whereas not with increment in free triiodothyronine level (P for trend >0.05). Additionally, in Euthy subgroup analyses stratified by middle‐age, sex and body mass index, a similar association was noted (all P for trend <0.05), but not in the older‐aged patients (P for trend >0.05).

Conclusions

Subclinical hyperthyroidism was an independent risk factor for presarcopenia in patients with type 2 diabetes mellitus, but subclinical hypothyroidism was not. In the Euthy group with type 2 diabetes mellitus, a high free thyroxine : free triiodothyronine ratio was a good index of presarcopenia in addition to older age.

Subclinical Hypothyroidism: Prevalence, Health Impact, and Treatment Landscape

Subclinical hypothyroidism (sHypo) is defined as normal serum free thyroid hormone levels coexisting with elevated serum thyroid-stimulating hormone (TSH) levels. sHypo is a common condition observed in clinical practice with several unique features. Its diagnosis should be based on an understanding of geographic and demographic differences in biochemical criteria versus a global reference range for TSH that is based on the 95% confidence interval of a healthy population. During the differential diagnosis, it is important to remember that a considerable proportion of sHypo cases are transient and reversible in nature; the focus is better placed on persistent or progressive forms, which mainly result from chronic autoimmune thyroiditis. Despite significant evidence documenting the health impacts of sHypo, the effects of levothyroxine treatment (LT4-Tx) in patients with sHypo remains controversial, especially in patients with grade 1 sHypo and older adults. Existing evidence suggests that it is reasonable to refrain from immediate LT4-Tx in most patients if they are closely monitored, except in women who are pregnant or in progressive cases. Future research is needed to further characterize the risks and benefits of LT4-Tx in different patient cohorts.

Expert consensus on diagnosis and treatment for elderly with thyroid diseases in China (2021)

In order to improve the diagnosis and treatment of senile thyroid diseases in China and to promote healthy aging, the Endocrine Metabolic Diseases Group of the Chinese Geriatrics Society, and the Thyroid Group of the Chinese Society of Endocrinology jointly drafted the "Expert consensus on diagnosis and treatment for Chinese elderly with thyroid diseases" (referred to as consensus). The Consensus consists of five parts that set 40 recommendations on main clinical issues. The consensus emphasizes clinical focus on the age-related changes of the hypothalamus-pituitary-thyroid axis in the elderly, and it recommends application of comprehensive geriatric assessment to thoroughly evaluate the impact of thyroid diseases and relevant intervention on overall health condition. Meanwhile, it recommends generalization of screening for hypothyroidism during admission to nursing institution or hospital, and routine health check-ups. Furthermore, it develops individualized stratified management on hyperthyroidism, hypothyroidism, thyroid nodules, and differentiated thyroid carcinoma in the elderly distinguished from the youngers, including treatment regimen, control ranges, and flowcharts for diagnosis and treatment. The Consensus will provide the basis for clinical decisions and health management of thyroid diseases in the elderly by geriatrician, endocrinologist, and general practitioners.

Skeletal health in patients with differentiated thyroid carcinoma

Osteoporosis and fractures are important comorbidities in patients with differentiated thyroid cancer (DTC), with potential negative impact on quality of life and survival. The main determinant of skeletal fragility in DTC is the thyrotropin (TSH)-suppressive therapy, which is commonly recommended to prevent disease's recurrence, especially in patients with structural incomplete response after thyroid surgery and radio-iodine therapy. TSH-suppressive therapy can stimulate bone resorption with consequent bone loss, deterioration of bone microstructure and high risk of fragility fractures. The skeletal effects of TSH-suppressive therapy may be amplified when thyroid cancer cells localize to the skeleton inducing alterations in bone remodelling, impairment of bone structure and further increase in risk of fractures. The management of skeletal fragility in DTC may be challenging, since prediction of fractures is a matter of uncertainty and data on effectiveness and safety of bone-active agents in this clinical setting are still scanty. This review deals with pathophysiological, clinical and therapeutic aspects of skeletal fragility of patients with DTC.

Low TSH Is Associated With Frailty in an Older Veteran Population Independent of Other Thyroid Function Tests

Low TSH is associated with frailty in the older adult. We studied whether low TSH is an independent marker of frailty or is an indicator of subclinical hyperthyroidism, which in turn predicts frailty. Of outpatient veterans seen between January 2005 and December 2016, we identified 100 patients aged ≥60 years with two low TSH (<0.5 µIU/ml) and one fT3 measurement and 50 matched controls (TSH 0.5–5.0 µIU/ml). We used a deficit accumulation approach to create a frailty index (FI). The higher the FI, the more likely (p<0.001) that patients had expired. Patients with low (0.31 ± 0.11 µIU/mL) versus normal (1.84 ± 0.84 µIU/mL) TSH had higher mean FI compared to controls (0.25 ± 0.12 vs. 0.15 ± 0.07, p < .001). Low TSH was significantly associated with frailty (p < .001), independent of age. However, lower TSH was not associated with higher fT3 or fT4 levels. There was a nonsignificant inverse association of fT3 levels with FI (p = .13), which disappeared when adjusted for age. Similar to prior studies, low TSH was associated with frailty. However, neither fT3 nor fT4 predicted low TSH or FI, suggesting that the association of low TSH with frailty is not due to subclinical hyperthyroidism, but perhaps to effects of comorbidities on TSH secretion.

Different Relationships Between Thyrotropin and Muscle Strength According to Sex and Age in Euthyroid Koreans (The 6th Korea National Health and Nutritional Examination Survey 2014-2015)

Background: Changes in muscle mass and strength can be caused by multiple endocrine factors, including thyroid dysfunction. However, the relationship between thyroid function and muscle strength in euthyroid individuals is not clear. In the present study, we investigated the relationship between thyroid function and handgrip strength (HGS) in euthyroid Koreans, especially according to sex and age. Methods: This was a population-based, cross-sectional study from the 6th Korea National Health and Nutrition Examination Survey including 2894 Koreans (1487 men and 1407 women) aged ≥19 years. Serum thyrotropin (TSH) and free thyroxine (fT4) levels were measured. HGS was measured using a digital grip strength dynamometer. Results: Serum TSH level, but not serum fT4 level, was significantly associated with HGS in men, but neither TSH nor fT4 level was associated with HGS in women. Serum TSH showed a negative association with HGS in men aged <65 years (n = 1376; β = -0.566, p = 0.008), but a positive association in men aged ≥65 years (n = 111; β = 1.158, p = 0.010) after adjusting for confounders. HGS decreased as TSH tertile increased in men aged <65 years (p for trend = 0.010), but increased with TSH tertile in men aged ≥65 years (p for trend = 0.009) after adjusting for confounders. Odds ratios (ORs) for the lowest quartile of HGS increased in the highest tertile of TSH among men aged <65 years (OR = 1.657 [95% confidence interval {CI} 1.099-2.500], p = 0.006) and decreased in the highest tertile of TSH among men aged ≥65 years (OR = 0.176 [CI 0.032-0.966], p = 0.034) after adjusting for confounders. Conclusions: In euthyroid Koreans, serum TSH levels were significantly associated with HGS only in men and this relationship was found to depend significantly on age. These findings suggest that age has a distinct influence on the effect of even subtle change of thyroid function on muscle strength in men.

Low free triiodothyronine levels are associated with risk of frailty in older adults with type 2 diabetes mellitus

OBJECTIVES

With aging populations around the world, frailty is becoming more prevalent increasing the need to early identify those at risk of frailty. The association between thyroid hormone levels and frailty in subjects with type 2 diabetes mellitus (T2DM) remains unclear. The objective of the study was to evaluate the relationship between thyroid hormone concentrations and frailty in older adults with T2DM.

METHODS

A total of 240 older adults with T2DM were divided into three groups according to the frailty phenotype criteria: robust group (n = 94), pre-frail (n = 110) and frail group (n = 36). Concentrations of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH), 25-hydroxyvitamin D₃ [25(OH) D₃], highly sensitive C-reactive protein (hs-CRP) and interleukin-6 (IL-6) were determined. Handgrip strength was measured using a Jamar hand dynamometer. Physical function was assessed by gait speed and the timed go and up (TUG) test. Logistic regression analysis was performed to evaluate the association between FT3 and frailty.

RESULTS

The FT3 level was the lowest among frail people (2.56 ± 0.42 pg/mL), followed by pre-frail participants (2.73 ± 0.38 pg/mL), with the highest among the robust subjects (2.83 ± 0.43 pg/mL). FT3 level was positively correlated with handgrip strength and gait speed (R = 0.313, P < 0.001; R = 0.250, P < 0.001, respectively), while negatively correlated with TUG time (R = -0.276, P < 0.001). After adjusting for age, sex, TSH, 25(OH) D₃ and estimate glomerular filtration rate (eGFR), logistic regression showed that low FT3 was significantly associated with an increased risk of frailty (odds ratio (OR): 4.53; 95% confidence interval (CI): 1.89-10.83; P = 0.001).

CONCLUSION

Low levels of FT3 were associated with an increased risk of frailty in older adults with T2DM. Measuring FT3 might be useful for identifying those at high risk of frailty.

[The thyroid gland in old age : Physiology and pathology]

In healthy older people the metabolism of thyroid hormones is physiologically altered and can possibly even actively contribute to longevity. This should also be taken into consideration in the treatment of diseases of the thyroid and principally also for younger patients. For example, with progressing age comorbidities become more prevalent and especially in cardiovascular diseases, hyperthyroidism is less well tolerated, and should be treated more aggressively. Benign multinodular goiter also becomes more prevalent in old age and should be surgically treated when causing mechanical symptoms. The treatment concept for malignant diseases should be adapted to the holistic situation of the patient but principally in the same manner as in younger patients. Old and very old patients also benefit from adequate, risk-adapted treatment of thyroid gland diseases so that appropriate diagnostics and clarification are meaningful, regardless of age.

A Significant Association of Upper Limb Muscle Strength with Thyroid Function in Overweight and Obese Population: A Study of the Sixth Korea National Health and Nutrition Examination Survey (KNHANES 2014-2015)

Background. As skeletal muscle is one of main targets of thyroid hormone signalling, an association of thyroid function and muscle strength could be expected. The aim of study is to evaluate the association of free thyroxine (FT4) and thyrotropin (TSH) with upper limb muscle strength, measured by hand grip strength, in subjects with normal FT4 from national representative data. The study utilized the sixth edition of the Korea National Health and Nutrition Examination Survey. After exclusion of subjects with FT4 level out of normal range, a history of thyroid disease or cerebral disease, restricted activity, and incomplete data, a total of 3503 were recruited (age range 19-80 years, 51% male). FT4 positively correlated with upper limb muscle strength (β coefficient = -12.84, p < 0.001), while TSH did negatively (β coefficient = -0.37, p=0.002). After adjusting for confounding factors, statistical significance disappeared. However, among subjects with BMI above 23 kg/m², a negative correlation of TSH with upper limb muscle strength was found in a younger age group (19-39 years old) (β coefficient = -0.56, p=0.021), while FT4 positively correlated with upper limb muscle strength (β coefficient = 3.24, p=0.019) in an older group (above 40 years old). In overweight and obese subjects, a significant association of thyroid function with upper limb muscle strength was observed in nation-wide representative data. High TSH in a younger group and low FT4 in an older group could be risk factors for decreased upper limb muscle strength in obese population.

Subclinical hypothyroidism and cardiovascular risk factors

INTRODUCTION

Thyroid hormones have multiple effects on lipid metabolism as well as on the cardiovascular system function. These negative cardiovascular effects have long been recognized in overt hypothyroidism but can be reversed by treatment with levothyroxine.

EVIDENCES ACQUISITION

We performed on PubMed a literature search for the articles published until March 2019 by using the search terms "subclinical hypothyroidism," "cardiovascular disease," "cholesterol," "LDL," "HDL," "triglycerides," "coronary heart disease," "heart failure," "atherosclerosis," "all-cause mortality," "levothyroxine."

EVIDENCES SYNTHESIS

Subclinical hypothyroidism, defined as an elevated thyrotropin (TSH) with a normal free thyroxine (FT4), is frequent in the general population and increase with age. Subclinical hypothyroidism has been linked to cardiovascular risk factors, dyslipidemia and increased atherosclerosis. Although some studies have demonstrated that lipids are elevated in subclinical hypothyroidism, other studies did not confirm these data. Clinical trials have also demonstrated there is no clear evidence that levothyroxine therapy in subjects with milder form (TSH<10 mU/L) of subclinical hypothyroidism could improve lipid status and the other cardiovascular risk factors. Nevertheless, TSH level seems the best predictor of cardiovascular disease, in particular when its levels are above 10 mU/L.

CONCLUSIONS

Prospective studies are necessary to clarify the cardiovascular risk in patients with mild subclinical hypothyroidism and to assess the importance of treating elderly people in order to improve or counteract the correlated risks. However, until clinical recommendations will be updated, the decision to treat or not treat patients with subclinical hypothyroidism will still base on clinical judgment, clinical practice guidelines, and expert opinion.

A defined human aging phenome

Aging is among the most complex phenotypes that occur in humans. Identifying the interplay between different age-associated features is undoubtedly critical to our understanding of aging and thus age-associated diseases. Nevertheless, what constitutes human aging is not well characterized. Towards this end, we mined millions of PubMed abstracts for age-associated terms, enabling us to generate a detailed description of the human aging phenotype. We discovered age-associated features in clusters that can be broadly associated with previously defined hallmarks of aging, consequently identifying areas where interventions could be pursued. Importantly, we validated the newly discovered features by manually verifying the prevalence of these features in combined cohorts describing 76 million individuals, allowing us to stratify features in aging that appear to be the most prominent. In conclusion, we propose a comprehensive landscape of human aging: the human aging phenome.

Association of thyroid function with sarcopenia in elderly Chinese euthyroid subjects

OBJECTIVES

With the increase in aging population worldwide, the incidence of sarcopenia is also increasing. Thyroid hormones are important regulators that can affect body composition and physical function. The association between thyroid hormone levels and sarcopenia in susceptible elderly euthyroid subjects remains unclear. In this study, we investigated the effect of thyroid hormone concentrations on body muscle mass, muscle strength and physical function related to sarcopenia in elderly Chinese euthyroid subjects.

METHODS

A total of 94 elderly Chinese euthyroid subjects (73 men, 21 women) without medications or diseases which obviously affected muscle metabolism or thyroid function were included in our study. Concentrations of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were determined by immunoassays. Appendicular skeletal muscle mass (ASM) was assessed by dual-energy X-ray absorptiometry. Handgrip strength was measured using a Jamar hand dynamometer, and physical function was assessed by the Short Physical Performance Battery (SPPB).

RESULTS

Muscle function, both handgrip strength and SPPB, was negatively associated with age, and FT3 demonstrated age-dependent decline. Pearson's correlation analysis showed positive associations of FT3 with ASM, handgrip strength and SPPB. Neither FT4 nor TSH was associated with these parameters of sarcopenia in euthyroid subjects. Significantly positive correlations between FT3 and ASM, handgrip strength and SPPB were also observed in multiple linear regression analysis adjusted for age, gender and BMI, while no significant correlations were found between FT4 or TSH and aforementioned four parameters of sarcopenia. Subjects with sarcopenia had lower level of FT3.

CONCLUSIONS

Higher FT3 concentration within normal range was correlated to muscle mass and muscle function in elderly subjects.

Which factors are associated with sarcopenia and frailty in elderly persons residing in the community?

Abstract Objective: to broaden knowledge about the factors associated with sarcopenia and frailty in elderly persons residing in the community. Method: an integrative systematic review based on the PRISMA recommendations was carried out, using articles published from 2012 to March 2017 in the PubMED, SciELO, Virtual Health Library, CINAHL and Springer electronic databases with the following descriptors: frail elderly, sarcopenia and etiology and their synonyms. The articles identified by the initial search strategy were independently assessed by two researchers, according to the eligibility criteria, and the articles selected were evaluated for methodological quality. Results: the results of this survey show that frailty may be associated with sarcopenia, low serum vitamin D levels, anemia, subclinical hyperthyroidism in men, while the greatest evolution in women was for osteoporosis. An association between sarcopenia and advanced age was also observed, with worsening quality of life, physical-functional capacity, nutritional status and comorbidities, as well as an increased risk of death in sarcopenic elderly persons. Conclusion: this systematic review showed that low serum levels of vitamin D are associated with frailty and factors that predispose this condition. It is therefore important to monitor the serum levels of this vitamin in the elderly population, and it is suggested that new studies are carried out related to supplements of this vitamin in frail elderly persons.

Frailty predicts short-term survival even in older adults without multimorbidity

BACKGROUND

Frailty and multimorbidity are both strongly associated with poor health-related outcomes, including mortality. Being multimorbidity one of the major determinants of frailty, we aimed to explore whether, and to what extent, frailty without multimorbidity plays an independent role in shortening life.

METHODS

We used data from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). Among the 3363 adults aged 60+ enrolled at baseline, those without multimorbidity (i.e.: less than two chronic diseases) (N = 1115) have been characterized according to Fried's frailty phenotype (i.e. robust, prefrail, and frail). The association between frailty and mortality was estimated using piecewise proportional hazard regression models in three five-year time periods.

RESULTS

Among participants without multimorbidity, 424 (38%) were prefrail and 19 (2%) were frail. During the 15-year follow-up, 263 (24%) participants died: 19%, 29%, and 63% of those who were robust, prefrail, and frail at baseline, respectively. Within the first 5 years of follow-up, prefrail and frail participants had more than doubled mortality risk in comparison to robust ones (HR for pre-frailty 2.08, 95% CI 1.15-3.76; HR for frailty 2.69, 95% CI 1.22-5.97). Beyond 5 years, a trend of increased mortality rate was still detectable for prefrail and frail subjects in comparison to robust ones.

CONCLUSIONS

Physical frailty and pre-frailty are associated with short-term mortality in a cohort of older adults free from multimorbidity. Frailty could be a clinical indicator of increased risk of negative health outcomes even among subjects without multiple chronic conditions.

Frailty and the endocrine system

Frailty is a condition characterised by loss of biological reserves, failure of homoeostatic mechanisms, and vulnerability to adverse outcomes. The endocrine system is considered particularly important in frailty, because of its complex inter-relationships with the brain, immune system, and skeletal muscle. This Review summarises evidence indicating a key role for the hypothalamic-pituitary axis in the pathogenesis of frailty through aberrant regulation of glucocorticoid secretion, insulin-like growth factor signalling, and androgen production. Evidence also indicates a potential role for vitamin D and insulin resistance in the pathogenesis of frailty. The role of thyroid hormones in the pathogenesis of frailty remains uncertain. Key convergent pathological effects of frailty include loss of muscle mass and strength, with consequent impact on mobility and activities of daily living. Future translational research should focus on the understanding of endocrine mechanisms, to identify potential biomarkers of the condition, modifiable targets for treatment, and novel pharmacological drugs targeted at the endocrine components of frailty.

The physiology of endocrine systems with ageing

During ageing, the secretory patterns of the hormones produced by the hypothalamic-pituitary axis change, as does the sensitivity of the axis to negative feedback by end hormones. Additionally, glucose homoeostasis tends towards disequilibrium with increasing age. Along with these endocrine alterations, a loss of bone and muscle mass and strength occurs, coupled with an increase in fat mass. In addition, ageing-induced effects are difficult to disentangle from the influence of other factors that are common in older people, such as chronic diseases, inflammation, and low nutritional status, all of which can also affect endocrine systems. Traditionally, the decrease in hormone activity during the ageing process has been considered to be detrimental because of the related decline in bodily functions. The concept of hormone replacement therapy was suggested as a therapeutic intervention to stop or reverse this decline. However, clearly some of these changes are a beneficial adaptation to ageing, whereas hormonal intervention often causes important adverse effects. In this paper, we discuss the effects of age on the different hypothalamic-pituitary-hormonal organ axes, as well as age-related changes in calcium and bone metabolism and glucose homoeostasis.

Association between subclinical thyroid dysfunction and change in bone mineral density in prospective cohorts

BACKGROUND

Subclinical hyperthyroidism (SHyper) has been associated with increased risk of hip and other fractures, but the linking mechanisms remain unclear.

OBJECTIVE

To investigate the association between subclinical thyroid dysfunction and bone loss.

METHODS

Individual participant data analysis was performed after a systematic literature search in MEDLINE/EMBASE (1946-2016). Two reviewers independently screened and selected prospective cohorts providing baseline thyroid status and serial bone mineral density (BMD) measurements. We classified thyroid status as euthyroidism (thyroid-stimulating hormone [TSH] 0.45-4.49 mIU/L), SHyper (TSH < 0.45 mIU/L) and subclinical hypothyroidism (SHypo, TSH ≥ 4.50-19.99 mIU/L) both with normal free thyroxine levels. Our primary outcome was annualized percentage BMD change (%ΔBMD) from serial dual X-ray absorptiometry scans of the femoral neck, total hip and lumbar spine, obtained from multivariable regression in a random-effects two-step approach.

RESULTS

Amongst 5458 individuals (median age 72 years, 49.1% women) from six prospective cohorts, 451 (8.3%) had SHypo and 284 (5.2%) had SHyper. During 36 569 person-years of follow-up, those with SHyper had a greater annual bone loss at the femoral neck versus euthyroidism: %ΔBMD = -0.18 (95% CI: -0.34, -0.02; I2 = 0%), with a nonstatistically significant pattern at the total hip: %ΔBMD = -0.14 (95% CI: -0.38, 0.10; I2 = 53%), but not at the lumbar spine: %ΔBMD = 0.03 (95% CI: -0.30, 0.36; I2 = 25%); especially participants with TSH < 0.10 mIU/L showed an increased bone loss in the femoral neck (%Δ BMD = -0.59; [95% CI: -0.99, -0.19]) and total hip region (%ΔBMD = -0.46 [95% CI: -1.05, -0.13]). In contrast, SHypo was not associated with bone loss at any site.

CONCLUSION

Amongst adults, SHyper was associated with increased femoral neck bone loss, potentially contributing to the increased fracture risk.

MANAGEMENT OF ENDOCRINE DISEASE: l-Thyroxine replacement therapy in the frail elderly: a challenge in clinical practice

The number of elderly people, mostly aged over 85 years (the 'oldest old'), is increasing worldwide. As a consequence, accompanying morbidity and disability have been increasing, and frailty, defined as an age-related condition of decline of physiological reserves and vulnerability, represents an emerging problem. Caring for older frail people may represent a challenge, since the elderly differ significantly from younger adults in terms of comorbidity, polypharmacy, pharmacokinetics and greater vulnerability to adverse drug reactions. Specific criteria of therapeutic appropriateness and modified goals of care are needed in such patients, also in endocrine care settings. Indeed, thyroid dysfunctions are among the most common conditions in older, multimorbid populations. The prevalence of overt and subclinical hypothyroidism is as high as 20% and thyroid hormone prescription is common in the elderly, with a trend toward levothyroxine treatment of more marginal degrees of hypothyroidism. In addition, older patients have the highest rate of overtreatment during replacement therapy and are more susceptible to developing adverse effects from thyroid hormone excess. Recently, results of a multicentric randomized controlled trial, the TRUST-IEMO collaboration trial, added further insights to the debated question of whether and when levothyroxine treatment is required and if it is beneficial in the elderly. With this in mind, we revised the relevant literature on the impact of thyroid dysfunction and replacement therapy among older people, with the aim to better define indications, benefits and risks of l-T4 replacement therapy in the frail elderly.

Frailty and sarcopenia - newly emerging and high impact complications of diabetes

Diabetes increases the risk of physical dysfunction and disability. Diabetes-related complications and coexisting morbidities partially explain the deterioration in physical function. The decline in muscle mass, strength and function associated with diabetes leads to sarcopenia, frailty and eventually disability. Frailty acts as a mediator in the pathogenesis of disability in older people with diabetes and its measurement in routine daily practice is recommended. Frailty is a dynamic process which progresses from a robust condition to a pre-frail stage then frailty and eventually disability. Therefore, a multimodal intervention which includes adequate nutrition, exercise training, good glycaemic control and the use of appropriate hypoglycemic medications may help delay or prevent the progression to disability.

Subclinical hypothyroidism: Should we treat?

Subclinical hypothyroidism (also known as compensated hypothyroidism or mild hypothyroidism) is a condition associated with a raised serum concentration of thyroid stimulating hormone (TSH) but a normal serum free thyroxine (FT4). It is common, affecting about 10% of women above the age of 55 years. Autoimmunity is the commonest cause of subclinical hypothyroidism. About 2.5% of patients with subclinical hypothyroidism progress to clinically overt hypothyroidism each year; the rate of progression is higher in patients with thyroid autoantibodies and higher thyroid stimulating hormone levels. However, thyroid function normalises spontaneously in up to 40% cases. Only a small minority of patients with subclinical hypothyroidism have symptoms, and the evidence to support that levothyroxine ameliorate the symptoms in these patients is weak. Subclinical hypothyroidism in younger patients (<65 years) is associated with an increased risk of coronary heart disease, heart failure and cerebrovascular disease. The risk increases with increasing levels of thyroid stimulating hormone, and is particularly high in patients with TSH levels ≥10.0 mu/L. There is lack of evidence from randomised controlled trials as to whether levothyroxine treatment can prevent these risks, although a large observational study of the UK general practice research database has shown that levothyroxine may reduce the risk of coronary heart disease in younger patients (<70 years). Therefore, the decision whether to treat or not to treat subclinical hypothyroidism should be made after careful consideration of the patient's age, the presence of symptoms, the presence of thyroid antibodies and other risk factors such as cardiovascular disease.

Thyroid hormones in extreme longevity

The aim of the present review was to summarize knowledge about thyroid hormones (THs) and longevity. Longevity is a complex multifactorial phenomenon on which specific biological pathways, including hormonal networks involved in the regulation of homeostasis and survival, exert a strong impact. THs are the key responsible for growth, metabolism rate and energy expenditure, and help in maintaining cognition, bone and cardiovascular health. THs production and metabolism are fine tuned, and may help the organism to cope with a variety of environmental challenges. Experimental evidence suggests that hypothyroid state may favor longevity by reducing metabolism rate, oxidative stress and cell senescence. Data from human studies involving healthy subjects and centenarians seem to confirm this view, but THs changes observed in older patients affected by chronic diseases cannot be always interpreted as a protective adaptive mechanism aimed at reducing catabolism and prolonging survival. Medications, selected chronic diseases and multi-morbidity can interfere with thyroid function, and their impact is still to be elucidated.

Subclinical hypothyroidism, lipid metabolism and cardiovascular disease

Subclinical hypothyroidism is defined by elevated serum thyrotropin in presence of normal free thyroid hormones. Lipid metabolism is influenced by thyroid hormone and many reports showed that lipids status worsen along with TSH level. Subclinical hypothyroidism has been also linked to other cardiovascular risk factors such as alteration in blood pressure and increased atherosclerosis. Further evidences suggested that mild dysfunction of thyroid gland is associated with metabolic syndrome and heart failure. Thyrotropin level seems the best predictor of cardiovascular disease, in particular when its levels are above 10mU/L. However, despite these observations, there is no clear evidence that levothyroxine therapy in subjects with milder form of subclinical hypothyroidism could improve lipid status and the other cardiovascular risk factors. In this review, we address the effect of thyroid hormone and cardiovascular risk, with a focus on lipid metabolism.

Frailty and sarcopenia as the basis for the phenotypic manifestation of chronic diseases in older adults

Frailty is a functional status that precedes disability and is characterized by decreased functional reserve and increased vulnerability. In addition to disability, the frailty phenotype predicts falls, institutionalization, hospitalization and mortality. Frailty is the consequence of the interaction between the aging process and some chronic diseases and conditions that compromise functional systems and finally produce sarcopenia. Many of the clinical manifestations of frailty are explained by sarcopenia which is closely related to poor physical performance. Reduced regenerative capacity, malperfusion, oxidative stress, mitochondrial dysfunction and inflammation compose the sarcopenic skeletal muscle alterations associated to the frailty phenotype. Inflammation appears as a common determinant for chronic diseases, sarcopenia and frailty. The strategies to prevent the frailty phenotype include an adequate amount of physical activity and exercise as well as pharmacological interventions such as myostatin inhibitors and specific androgen receptor modulators. Cell response to stress pathways such as Nrf2, sirtuins and klotho could be considered as future therapeutic interventions for the management of frailty phenotype and aging-related chronic diseases.