Thyroid autoantibodies are associated with a reduced prevalence of frailty in community-dwelling older women

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.

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.

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.

Long COVID in Patients With Mild to Moderate Disease: Do Thyroid Function and Autoimmunity Play a Role?

OBJECTIVE

Post-acute sequelae of coronavirus disease 2019 (COVID-19) or long COVID (LC) is an emerging global health issue. Fatigue is a common feature. Whether thyroid function and autoimmunity play a role is uncertain. We aimed to evaluate the prevalence and predictors of LC and the potential role of thyroid function and autoimmunity in LC.

METHODS

We included consecutive adults without a known thyroid disorder who were admitted to a major COVID-19 center for confirmed COVID-19 from July to December 2020. Thyroid function tests and antithyroid antibodies were measured for all patients on admission and at follow-up. LC was defined by the presence or persistence of symptoms upon follow-up.

RESULTS

In total, 204 patients (median age, 55.0 years; 95 men [46.6%]) were reassessed at a median of 89 days (interquartile range, 69-99) after acute COVID-19. Of the 204 patients, 41 (20.1%) had LC. Female sex (adjusted odds ratio, 2.48; P = .018) and severe acute respiratory syndrome coronavirus 2 polymerase chain reaction cycle threshold value of <25 on admission (adjusted odds ratio, 2.84; P = .012) independently predicted the occurrence of LC. Upon follow-up, most abnormal thyroid function tests in acute COVID-19 resolved, and incident thyroid dysfunction was rare. Nonetheless, we observed incident antithyroid peroxidase (anti-TPO) positivity. Although baseline or follow-up thyroid function tests were not associated with the occurrence of LC, among 172 patients with symptomatic acute COVID-19, symptom resolution was more likely in those with positive anti-TPO upon follow-up (P = .043).

CONCLUSION

LC is common among COVID-19 survivors, with females and those with higher viral load in acute COVID-19 particularly being vulnerable. The observation of incident anti-TPO positivity warrants further follow-up for thyroid dysfunction. Whether anti-TPO plays a protective role in LC remains to be elucidated.

Levothyroxine Therapy in Elderly Patients With Hypothyroidism

Levothyroxine (L-T4) treatment of overt hypothyroidism can be more challenging in elderly compared to young patients. The elderly population is growing, and increasing incidence and prevalence of hypothyroidism with age are observed globally. Elderly people have more comorbidities compared to young patients, complicating correct diagnosis and management of hypothyroidism. Most importantly, cardiovascular complications compromise the usual start dosage and upward titration of L-T4 due to higher risk of decompensating cardiac ischemia and -function. It therefore takes more effort and care from the clinician, and the maintenance dose may have to be lower in order to avoid a cardiac incidence. On the other hand, L-T4 has a beneficial effect on cardiac function by increasing performance. The clinical challenge should not prevent treating with L-T4 should the patient develop e.g., cardiac ischemia. The endocrinologist is obliged to collaborate with the cardiologist on prophylactic cardiac measures by invasive cardiac surgery or medical therapy against cardiac ischemic angina. This usually allows subsequent successful treatment. Management of mild (subclinical) hypothyroidism is even more complex. Prevalent comorbidities in the elderly complicate correct diagnosis, since many concomitant morbidities can result in non-thyroidal illness, resembling mild hypothyroidism both clinically and biochemically. The diagnosis is further complicated as methods for measuring thyroid function (thyrotropin and thyroxine) vary immensely according to methodology and background population. It is thus imperative to ensure a correct diagnosis by etiology (e.g., autoimmunity) before deciding to treat. Even then, there is controversy regarding whether or not treatment of such mild forms of hypothyroidism in elderly will improve mortality, morbidity, and quality of life. This should be studied in large cohorts of patients in long-term placebo-controlled trials with clinically relevant outcomes. Other cases of hypothyroidism, e.g., medications, iodine overload or hypothalamus-pituitary-hypothyroidism, each pose specific challenges to management of hypothyroidism; these cases are also more frequent in the elderly. Finally, adherence to treatment is generally challenging. This is also the case in elderly patients, which may necessitate measuring thyroid hormones at individually tailored intervals, which is important to avoid over-treatment with increased risk of cardiac morbidity and mortality, osteoporosis, cognitive dysfunction, and muscle deficiency.

Antinuclear Autoantibodies in Health: Autoimmunity Is Not a Synonym of Autoimmune Disease

The incidence of autoimmune diseases is increasing. Antinuclear antibody (ANA) testing is a critical tool for their diagnosis. However, ANA prevalence in healthy persons has increased over the last decades, especially among young people. ANA in health occurs in low concentrations, with a prevalence up to 50% in some populations, which demands a cutoff revision. This review deals with the origin and probable physiological or compensatory function of ANA in health, according to the concept of immunological clearance, theory of autoimmune regulation of cell functions, and the concept of functional autoantibodies. Considering ANA titers ≤1:320 as a serological marker of autoimmune diseases seems inappropriate. The role of anti-DFS70/LEDGFp75 autoantibodies is highlighted as a possible anti-risk biomarker for autoimmune rheumatic disorders. ANA prevalence in health is different in various regions due to several underlying causes discussed in the review, all influencing additive combinations according to the concept of the mosaic of autoimmunity. Not only are titers, but also HEp-2 IFA) staining patterns, such as AC-2, important. Accepting autoantibodies as a kind of bioregulator, not only the upper, but also the lower borders of their normal range should be determined; not only their excess, but also a lack of them or "autoimmunodeficiency" could be the reason for disorders.

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.

Circulating biomarkers characterizing physical frailty: CRP, hemoglobin, albumin, 25OHD and free testosterone as best biomarkers. Results of a meta-analysis

INTRODUCTION

During aging, individuals can be classified as being in one of 3 different states: robust, frail or dependent. Frailty is described as reversible, so early detection offers the potential of returning the subject to a robust status. There are multiple clinical frailty scales but no gold standard and frailty is not systematically assessed in clinicians' daily practice. Reliable biomarkers of frailty are lacking, however, while their identification and systematic use would make this simple scale a useful clinical tool.

OBJECTIVE

To conduct a review of the literature concerning the biomarkers associated with frailty and to compare in a meta-analysis the plasmatic values of each biomarker in the frail with the robust group.

RESULTS

503 articles were identified on PubMed, 467 on Scopus and 369 on Web Of Science. 67 articles were included, collecting a total of 32,934 robust subjects and 6864 frail subjects. C-reactive protein (CRP) (Standardized Mean Difference (SMD): 0.49 CI 95% [0.37-0.61]) was significantly higher in the frail group whereas hemoglobin (SMD: -0.67[-0.90; -0.44]), albumin (SMD: -0.62[-0.84; -0.41]), 25-hydroxyvitamin D (25OHD) (SMD: -0.43 [-0.64; -0.21]) and, in men, free testosterone (SMD: -0.77 [-1.05; -0.49]) were significantly lower in the frail group.

CONCLUSION

We found 5 biomarkers that were associated with frailty (CRP, hemoglobin, albumin, 25OHD and free testosterone in men) belonging to multiple physiological systems. Further cohort studies are needed to verify their ability to screen for frailty.

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.

High Circulating Free Thyroxine Levels May Increase the Risk of Frailty: The Rotterdam Study

CONTEXT

Thyroid hormones affect metabolism in various tissues, organs, and systems. However, the overall impact of thyroid function on an individual's vulnerability to adverse outcomes remains unclear.

OBJECTIVE

To investigate the cross-sectional and prospective association of thyroid function with the frailty index, a well-established measure of overall health.

DESIGN AND SETTING

The Rotterdam Study, a population-based, prospective cohort study.

PARTICIPANTS AND MAIN OUTCOME MEASUREMENTS

Participants with baseline measurements of thyroid function and the frailty index were eligible. The frailty index was measured at baseline and after a median follow-up time of 10.1 years (interquartile range, 5.7 to 10.8 years). A higher frailty index indicated a worse health state. We assessed the association of thyroid function with frailty at baseline, frailty at follow-up, and frailty changes over time, adjusting for age, sex, cohort, smoking, alcohol, and education.

RESULTS

We included 9640 participants (mean age, 64.9 years). There was a U-shaped association of thyrotropin (TSH; P < 0.0003) and free thyroxine (FT4; P < 0.0001) with frailty at baseline. There was no association of TSH, but a positive association of FT4 with frailty at follow-up and frailty changes over time (β, 1.22; confidence interval, 0.73 to 1.72 per 1 unit FT4).

CONCLUSION

In this population-based study, participants with low and high thyroid function were more likely to be frail than participants with normal thyroid function. However, only those with higher FT4 levels had an increased risk of becoming more frail over time. The identification of FT4 as a potential marker of health deterioration could have future implications regarding the prediction and prevention of frailty.

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.

Thyroid Autoimmunity: Role of Anti-thyroid Antibodies in Thyroid and Extra-Thyroidal Diseases

Autoimmune diseases have a high prevalence in the population, and autoimmune thyroid disease (AITD) is one of the most common representatives. Thyroid autoantibodies are not only frequently detected in patients with AITD but also in subjects without manifest thyroid dysfunction. The high prevalence raises questions regarding a potential role in extra-thyroidal diseases. This review summarizes the etiology and mechanism of AITD and addresses prevalence of antibodies against thyroid peroxidase, thyroid-stimulating hormone receptor (TSHR), and anti-thyroglobulin and their action outside the thyroid. The main issues limiting the reliability of the conclusions drawn here include problems with different specificities and sensitivities of the antibody detection assays employed, as well as potential confounding effects of altered thyroid hormone levels, and lack of prospective studies. In addition to the well-known effects of TSHR antibodies on fibroblasts in Graves' disease (GD), studies speculate on a role of anti-thyroid antibodies in cancer. All antibodies may have a tumor-promoting role in breast cancer carcinogenesis despite anti-thyroid peroxidase antibodies having a positive prognostic effect in patients with overt disease. Cross-reactivity with lactoperoxidase leading to induction of chronic inflammation might promote breast cancer, while anti-thyroid antibodies in manifest breast cancer might be an indication for a more active immune system. A better general health condition in older women with anti-thyroid peroxidase antibodies might support this hypothesis. The different actions of the anti-thyroid antibodies correspond to differences in cellular location of the antigens, titers of the circulating antibodies, duration of antibody exposure, and immunological mechanisms in GD and Hashimoto's thyroiditis.

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.

Iodine Status of New Zealand Elderly Residents in Long-Term Residential Care

In response to the re-emergence of iodine deficiency in New Zealand, in 2009 the government mandated that all commercially made breads be fortified with iodized salt. There has been no evaluation of the impact of the program on iodine status of the elderly, despite this population group being vulnerable to iodine deficiency or excess. The aim of this study was to describe the iodine status of elderly New Zealanders in residential aged-care homes following the implementation of the bread fortification program. A cross-sectional survey was conducted, involving 309 residents (median age 85 years) from 16 aged-care homes throughout NZ. Information on socio-demographic, anthropometric, dietary and health characteristics were collected. Casual spot urine samples were analysed for urinary iodine concentration (UIC). Blood samples were analysed for serum thyroglobulin, thyroglobulin antibodies, and other biochemical indices. The median UIC (MUIC) of the residents was 72 μg/L, indicating mild iodine deficiency, and 29% had a UIC < 50 μg/L. Median thyroglobulin concentration was 18 ng/mL and 26% had elevated thyroglobulin concentration (>40 ng/mL), suggesting iodine insufficiency. Diuretic use was associated with lower MUIC (p = 0.043). Synthetic thyroxine use was associated with lower odds of having a UIC < 50 μg/L (OR 0.32, p = 0.030)) and lower median thyroglobulin (−15.2 ng/mL, p = 0.001), compared with untreated participants. Frailty was associated with elevated thyroglobulin (p = 0.029), whereas anemia was associated with lower thyroglobulin (p = 0.016). Iodine insufficiency persists in New Zealanders residing in residential aged-care homes despite increasing iodine intake from fortified bread. Research is required to establish optimal iodine intake and status in the elderly.

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.

Subclinical Thyroid Dysfunction and Frailty Among Older Men

CONTEXT

Both subclinical thyroid dysfunction and frailty are common among older individuals, but data on the relationship between these 2 conditions are conflicting.

OBJECTIVE

The purpose of this study was to assess the cross-sectional and prospective associations between subclinical thyroid dysfunction and frailty and the 5 frailty subdomains (sarcopenia, weakness, slowness, exhaustion, and low activity).

SETTING AND DESIGN

The Osteoporotic Fractures in Men Study is a prospective cohort study.

PARTICIPANTS

Men older than 65 years (n = 1455) were classified into 3 groups of thyroid status: subclinical hyperthyroidism (n = 26, 1.8%), subclinical hypothyroidism (n = 102, 7.0%), and euthyroidism (n = 1327, 91.2%).

MAIN OUTCOME MEASURES

Frailty was defined using a slightly modified Cardiovascular Health Study Index: men with 3 or more criteria were considered frail, men with 1 to 2 criteria were considered intermediately frail, and men with no criteria were considered robust. We assessed the cross-sectional relationship between baseline thyroid function and the 3 categories of frailty status (robust/intermediate/frail) as well as the prospective association between baseline thyroid function and subsequent frailty status and mortality after a 5-year follow-up.

RESULTS

At baseline, compared with euthyroid participants, men with subclinical hyperthyroidism had an increased likelihood of greater frailty status (adjusted odds ratio, 2.48; 95% confidence interval, 1.15-5.34), particularly among men aged <74 years at baseline (odds ratio for frailty, 3.63; 95% confidence interval, 1.21-10.88). After 5 years of follow-up, baseline subclinical hypothyroidism and hyperthyroidism were not consistently associated with overall frailty status or frailty components.

CONCLUSION

Among community-dwelling older men, subclinical hyperthyroidism, but not subclinical hypothyroidism, is associated with increased odds of prevalent but not incident frailty.

Clinical features of prefrail older individuals and emerging peripheral biomarkers: a systematic review

Frailty is a geriatric syndrome characterized by the clinical presentation of identifiable physical alterations such as loss of muscle mass and strength, energy and exercise tolerance, and decreased physiological reserve. Individuals with one or two of these alterations are defined as prefrail. The clinical features of prefrail older individuals have been investigated to a lesser extent compared to the frail population, even though this intermediate stage may provide insights into the mechanisms involved in the physical decline associated with aging and it is considered to be potentially reversible. We performed searches in the Medline, Embase, Scopus, Cinahl, and Cochrane databases from January 1995 to July 2013 for papers about the identification of prefrail people aged 65 and older published either in English or Spanish, and the reference lists of from the articles retrieved were pearled in order to identify any which may have been missed in the initial search. Two independent reviewers extracted descriptive information on frailty criteria and outcomes from the selected papers: of the 277 articles retrieved from the searches and 25 articles retrieved from pearling, 84 met the study inclusion criteria. The prevalence of prefrailty ranges between 35% and 50% in individuals aged over 60, is more common in women, and the age and the number of comorbidities in these individuals is similar to their frail counterparts. Weakness is the most prevalent symptom in prefrail individuals although there are some sex differences. Some serum biomarkers seem to discriminate prefrail from non-frail individuals but further research would be required to confirm this.

Measures of frailty in population-based studies: an overview

Background

Although research productivity in the field of frailty has risen exponentially in recent years, there remains a lack of consensus regarding the measurement of this syndrome. This overview offers three services: first, we provide a comprehensive catalogue of current frailty measures; second, we evaluate their reliability and validity; third, we report on their popularity of use.

Methods

In order to identify relevant publications, we searched MEDLINE (from its inception in 1948 to May 2011); scrutinized the reference sections of the retrieved articles; and consulted our own files. An indicator of the frequency of use of each frailty instrument was based on the number of times it had been utilized by investigators other than the originators.

Results

Of the initially retrieved 2,166 papers, 27 original articles described separate frailty scales. The number (range: 1 to 38) and type of items (range of domains: physical functioning, disability, disease, sensory impairment, cognition, nutrition, mood, and social support) included in the frailty instruments varied widely. Reliability and validity had been examined in only 26% (7/27) of the instruments. The predictive validity of these scales for mortality varied: for instance, hazard ratios/odds ratios (95% confidence interval) for mortality risk for frail relative to non-frail people ranged from 1.21 (0.78; 1.87) to 6.03 (3.00; 12.08) for the Phenotype of Frailty and 1.57 (1.41; 1.74) to 10.53 (7.06; 15.70) for the Frailty Index. Among the 150 papers which we found to have used at least one of the 27 frailty instruments, 69% (n = 104) reported on the Phenotype of Frailty, 12% (n = 18) on the Frailty Index, and 19% (n = 28) on one of the remaining 25 instruments.

Conclusions

Although there are numerous frailty scales currently in use, reliability and validity have rarely been examined. The most evaluated and frequently used measure is the Phenotype of Frailty.

The immunopathogenesis of chronic autoimmune thyroiditis one century after hashimoto

Hakaru Hashimoto described 4 patients with a hitherto unknown cause for goitre, struma lymphomatosa, a century ago. He was careful to distinguish this from Riedel thyroiditis but it has become clear that fibrosis and atrophy of the thyroid are indeed components of Hashimoto thyroiditis, and in rare cases IgG4-related sclerosing disease may be an outcome. Although the cause of the lymphocytic infiltration was unknown to Hashimoto, we now know through the pioneering studies of N.R. Rose and E. Witebsky [J Immunol 1956;76:417-427] that this condition is the archetype for autoimmune destruction as a disease mechanism. In the last two decades in particular, there has been huge interest in unravelling the genetic basis for this and related autoimmune disorders. The list of polymorphisms associated with autoimmune thyroid disease grows each year, and in the case of vitiligo, which is frequently found in association with thyroid autoimmunity, we know that 27 separate susceptibility loci account for less than 20% of the heritability of this condition. Environmental and existential factors may turn out to be just as complex in number and in interactions. We can thus imagine a 'Swiss cheese' model for the causation of autoimmune thyroid disease, in which the effects of cumulative weaknesses line up - like the holes in slices of cheese - to allow the catastrophic event of autoimmune destruction to occur.

Higher free thyroxine levels are associated with frailty in older men: the Health In Men Study

OBJECTIVE

Frailty is common in the elderly and predisposes to ill-health. Some symptoms of frailty overlap those of thyroid dysfunction, but it is unclear whether differences in thyroid status influence risk of frailty. We evaluated associations between thyroid status and frailty in older men.

DESIGN

Cross-sectional epidemiological study.

PARTICIPANTS

Community-dwelling men aged 70-89 years.

MEASUREMENTS

Circulating thyrotropin (TSH) and free thyroxine (FT(4) ) were assayed. Frailty was assessed as ≥3 of the Fatigue, Resistance, Ambulation, Illnesses and Loss (FRAIL) scale's 5 domains: fatigue; resistance (difficulty climbing flight of stairs); ambulation (difficulty walking 100 m); illness (>5); or weight loss (>5%), blinded to hormone results.

RESULTS

Of 3943 men, 27 had subclinical hyperthyroidism, 431 subclinical hypothyroidism and 608 were classified as being frail (15·4%). There was an inverse log-linear association of TSH with FT(4). There was no association between TSH and frailty. After adjusting for covariates, men with FT(4) in the highest two quartiles had increased odds of being frail (Q3:Q1, odds ratio [OR] = 1·32, 95% confidence interval [CI] = 1·01-1·73 and Q4:Q1, OR = 1·36, 95% CI = 1·04-1·79, P = 0·010 for trend). Higher FT(4) was associated with fatigue (P = 0·038) and weight loss (P < 0·001). The association between FT(4) and frailty remained significant when the analysis was restricted to euthyroid men.

CONCLUSIONS

High-normal FT(4) level is an independent predictor of frailty among ageing men. This suggests that even within the euthyroid range, circulating thyroxine may contribute to reduced physical capability. Further studies are needed to clarify the utility of thyroid function testing and the feasibility of preventing or reversing frailty in older men.

The frailty syndrome: a comprehensive review

The frailty syndrome is defined as unintentional weight and muscle loss, exhaustion, and declines in grip strength, gait speed, and activity. Evidence with respect to the clinical definition, epidemiology, mechanisms, interactions, assessment, prevention, and treatment of frailty in the older adult is reviewed.