Mild thyroid hormone excess is associated with a decreased physical function in elderly men

Associations between low muscle mass and clinical characteristics of health population in China

Objectives

The primary aim of this study is to discern the association between specific clinical parameters and low muscle mass (LMM). We endeavor to elucidate the determinants of LMM and the predictive potency of individual factors.

Methods

In this retrospective cross-sectional study, we encompassed 450 older adult Chinese participants (252 males and 198 females). Muscle mass quantifications were performed using bioelectrical impedance analysis. Comprehensive data encompassing demographic details (age, sex, height, and weight) and laboratory results (complete blood count, thyroid function, liver function, and renal function) were systematically recorded. Logistic regression models, coupled with receiver operating characteristic curve analytics, were employed to ascertain the variables influencing LMM and to evaluate the predictive validity of each parameter on LMM.

Results

Upon confounding adjustment for age, gender, body mass index (BMI), and free thyroxine (FT4) persisted as a determinant of LMM. Specifically, individuals with an FT4 exceeding 1.105 ng/dL exhibited a 1.803-fold increased propensity for LMM relative to those with FT4 values below the specified threshold. Incorporating age, gender, BMI, and FT4 in the diagnostic algorithm enhanced the precision of LMM. The results differ between men and women. In the male population, we can still observe that FT4 has a certain value in the diagnosis of LMM, but this phenomenon is not found in the female population.

Conclusions

Elevated FT4 concentrations, albeit within clinically accepted limits, are inversely associated with muscle mass. As such, FT4 could be postulated as a potential biomarker for LMM in geriatric individuals, especially in the male group.

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.

Higher thyroid hormone has a negative association with lower limb lean body mass in euthyroid older adults: Analysis from the Baltimore Longitudinal study of aging

Background: Hyperthyroidism is associated with lower lean body mass, as a result of catabolic actions of thyroid hormone. Therefore, higher thyroid hormone levels could be a factor in the development of sarcopenia and age associated functional decline. The relationship between thyroid hormone and muscle mass in ambulatory, euthyroid older adults is not known. Method: We used mixed-effects models to estimate the cross-sectional relationships (accounting for inter-person variability) between thyroid axis hormone measures and lower limb composition or sarcopenia at visits in the Baltimore Longitudinal Study of Aging (BLSA) at which DEXA scans were available and both thyrotropin (TSH) and free thyroxine (FT4) were in the reference range. Analyses were adjusted for levothyroxine use, age, race, sex, BMI, smoking, alcohol intake, cholesterol, and systolic blood pressure. Results: 1442 euthyroid participants (median age 68, 50% female, and 69% white) contributed to 5306 visits from 2003 to 2019. FT4 was negatively associated with lower limb lean mass (beta: 88.49; 95% Confidence Interval (CI): 122.78, -54.20; p < 0.001) and positively associated with sarcopenia (OR: 1.11%, 95% CI: 1.01, 1.22) in the whole cohort. Additionally, higher FT4 was associated with lower leg lean mass (beta: 66.79; 95% CI: 102.24, -31.33; p < 0.001) and sarcopenia (OR:1.09%, 95% CI:1.01, 1.18) in older adults, but not in younger adults alone. Conclusion: In euthyroid older adults, higher FT4 is associated with lower leg lean mass and higher odds of sarcopenia. Understanding the relationship between thyroid hormone and sarcopenia is needed to improve clinical decision-making and avoid functional decline from excess thyroid hormone use in older adults.

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.

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.

The prospective relationship between low muscle mass and thyroid hormones among 198 069 euthyroid men and women; comparing different definitions of low muscle mass

OBJECTIVE

The impact of thyroid hormones within normal range on muscle mass remains unknown. We examined the association between new onset of low muscle mass (LMM) and thyroid hormones among euthyroid men and women with three different definitions of LMM in prospective cohort study.

METHODS

We performed a cohort study of 198 069 Korean adults (mean age of 39.2 years), free of LMM at baseline, who participated in a repeated screening examination and were followed up annually or biennially for up to 6.3 years. Thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxin (FT4) levels were measured by an electrochemiluminescent immunoassay. Muscle mass was assessed using a bioelectrical impedance analyser. LMM was defined as the appendicular skeletal muscle mass (ASM) by body weight (ASM/weight, LMM-W), height squared (ASM/height² , LMM-H) and BMI (ASM/BMI, LMM-B) of one standard deviation below the sex-specific mean for young reference group.

RESULTS

During a median follow-up of 3.1 years (interquartile range, 2.0-4.1 years), new-onset LMM-W, LMM-H and LMM-B occurred in 17 856 (incident rate, 27.8 per 1000 person-years), 8307 (incident rate, 13.4 per 1000 person-years) and 13 990 participants (incident rate, 24.5 per 1000 person-years) in each. In euthyroid men, FT4 was inversely and FT3 positively associated with incident LMM-W in a dose-response manner. TSH and FT4 had inverse dose-response relationship with incident LMM-B. Incident LMM-H of euthyroid men has no apparent associations with any thyroid hormones. Euthyroid women had no dose-response relationship between thyroid hormones and any definition of LMM.

CONCLUSIONS

Among euthyroid men, FT4 had inverse dose-response association with new onset of LMM defined with weight (LMM-W) and BMI (LMM-B). Height squared LMM (LMM-H) had no apparent relationship with any thyroid hormones. Euthyroid women had no dose-responsive association between thyroid hormones and incident LMM.

Fall-Associated Drugs in Community-Dwelling Older Adults: Results from the ActiFE Ulm Study

OBJECTIVES

Many studies describing an association of drugs with falls focus mostly on drugs acting in the central nervous system. We aim to analyze the association of all drugs taken with falls in older adults.

DESIGN

Prospective population-based study (ActiFE study).

SETTING AND PARTICIPANTS

A total of 1377 community-dwelling older adults with complete recording of falls and baseline information on drug intake.

METHODS

Negative binomial regression was used to analyze the association of 34 drug classes with a 12-month incidence rate ratio (IRR) of falls adjusting for age, sex, comorbidities, gait speed, balance, chair rise, kidney function, liver disease, and smoking.

RESULTS

Participants took a median 3 drugs (interquartile range 1, 5), with 34.5% (n = 469) having ≥5 drugs. The median IRR for a fall per person-year was overall 0.72 [95% confidence interval (CI) 0.60-0.83] and 2.22 (95% CI 1.90-2.53) among those who experienced ≥1 fall. The following drug classes showed significant associations: antiparkinsonian medication [IRR 2.68 (95% CI 1.59-4.51)], thyroid therapy [IRR 1.40 (95% CI 1.08-1.81)], and systemic corticosteroids [IRR 0.33 (95% CI 0.13-0.81)]. Among fall-risk-increasing drugs only antiepileptics [IRR 2.16 (95% CI 1.10-4.24)] and urologicals [IRR 2.47 (95% CI 1.33-4.59)] were associated with falls in those participants without a prior fall history at baseline.

CONCLUSION AND IMPLICATIONS

Additional drug classes, such as antiparkinsonian medication, thyroid therapy, and systemic corticosteroids, might be associated with falls in older adults, possibly representing pharmacological effects on the musculoskeletal and central nervous systems. Further evaluations in larger study populations are recommended.

Average urinary flow rate and its association with handgrip strength

BACKGROUND

Voiding dysfunction became a difficult problem for the elderly because of the underactive bladder (UAB). It was considered that the degeneration of detrusor muscle was the main etiology. In recent years, more articles focus on relationship between UAB and decreased muscle strength. Besides, handgrip strength (HGS) is an early indicator to detect frailty and muscle weakness in systemic reviews.

METHOD

Our study involved 2258 males from NHANES datasets (2011-2012, who were divided into quartiles by urine flow rate (UFR), which was measured by uroflowmetry. Multivariate regression models were performed to analyze the associations between UFR and HGS.

RESULTS

The UFR had a positive correlation to the HGS by multivariate regression models in males (β coefficient: 1.348, 95% confidence interval (CI): 0.530, 2.166, p = 0.001). The male participants with the highest quartile of UFR have a greater HGS than those with lowest quartile of UFR (β coefficient: 4.546, 95% CI: 2.462, 6.630, p < 0.001). Higher UFR was associated with lower odds of low HGS (OR: 0.489, 95% CI: 0.350, 0.684, p < 0.001) in the fully-adjusted model.

CONCLUSIONS

Our research highlighted that the UFR had a strong associated with the HGS in the healthy group.

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.

Thyroid hormone signaling is associated with physical performance, muscle mass, and strength in a cohort of oldest-old: results from the Mugello study

Thyroid hormones (THs) play a crucial role in the homeostasis of muscle function, such as myogenesis and energy metabolism, suggesting that the thyroid may be also involved in the entropic processes of muscle aging. The aim of the present study is to evaluate the effect of TH signaling on physical performance, muscle mass, and strength in a cohort of community-dwelling oldest-old subjects (> 90 years). The study population was selected in a rural area of central Italy (Mugello, Tuscany), and the design was cross-sectional. Four hundred seventy-five subjects (130 males and 345 females) were enrolled, representing about 65% of all the nonagenarians living in the Mugello area. After adjusting for multiple confounding factors (sex, age, diabetes, and levothyroxine administration), the lowest quartile of FT3/FT4 ratio distribution showed lower physical performance compared to the other quartiles (β ± SE: − 0.49 ± 0.12; p < 0.001), whereas the highest quartile of FT3/FT4 ratio was associated with higher skeletal muscle index (β ± SE: 1.11 ± 0.42; p = 0.009). In addition, the lowest quartile of FT4 showed a statistically significant higher handgrip strength (β ± SE: 1.78 ± 0.68; p = 0.009) compared to all other quartiles. This study demonstrates that nonagenarians with higher FT3/FT4 ratios had better preserved muscle function, therefore successfully overcoming the imbalance of homeostatic and entropic processes involved in muscle aging. However, we could not establish a cause-effect relationship due to the cross-sectional design of the study.

Thyroid hormones in diabetes, cancer, and aging

Thyroid function is central in the control of physiological and pathophysiological processes. Studies in animal models and human research have determined that thyroid hormones modulate cellular processes relevant for aging and for the majority of age‐related diseases. While several studies have associated mild reductions on thyroid hormone function with exceptional longevity in animals and humans, alterations in thyroid hormones are serious medical conditions associated with unhealthy aging and premature death. Moreover, both hyperthyroidism and hypothyroidism have been associated with the development of certain types of diabetes and cancers, indicating a great complexity of the molecular mechanisms controlled by thyroid hormones. In this review, we describe the latest findings in thyroid hormone research in the field of aging, diabetes, and cancer, with a special focus on hepatocellular carcinomas. While aging studies indicate that the direct modulation of thyroid hormones is not a viable strategy to promote healthy aging or longevity and the development of thyromimetics is challenging due to inefficacy and potential toxicity, we argue that interventions based on the use of modulators of thyroid hormone function might provide therapeutic benefit in certain types of diabetes and cancers.

Thyroid Function and Sarcopenia: Results from the ELSA-Brasil Study

OBJECTIVES

We aimed to investigate the association of subclinical thyroid disease and thyroid hormone levels with sarcopenia and its defining components in community-dwelling middle-aged and older adults without overt thyroid dysfunction.

DESIGN

Cross-sectional study.

SETTING

Active and retired employees from public institutions located in six Brazilian cities.

PARTICIPANTS

A total of 6974 participants from the ELSA-Brasil study's second wave, aged 50 years and older, without overt thyroid dysfunction and with complete data for exposure, outcome, and covariates.

METHODS

Serum levels of thyrotropin (TSH), free thyroxine, and free triiodothyronine (FT3) were measured and divided in quintiles for the analyses. Participants were classified with euthyroidism, subclinical hypothyroidism, and subclinical hyperthyroidism. Muscle mass was assessed by bioelectrical impedance analysis and muscle strength by handgrip strength. Sarcopenia was defined according to the Foundation for the National Institutes of Health criteria. Possible confounders included sociodemographic characteristics, clinical conditions, and lifestyle. Analyses were performed separately for middle-aged and older adults (≥65 y).

RESULTS

The frequencies of sarcopenia, low muscle mass, low muscle strength, subclinical hypothyroidism, and subclinical hyperthyroidism were 1.5%, 20.8%, 3.8%, 9.1%, and .9%, respectively. Subclinical thyroid dysfunction was not associated with sarcopenia and its defining components. Among older adults, TSH had a U-shaped association with sarcopenia and low muscle strength. The odds ratios (ORs) (95% confidence intervals [CIs]) for the associations of the first, second, fourth, and fifth quintile with sarcopenia, respectively, were 5.18 (1.47-18.28), 6.28 (1.82-21.73), 4.12 (1.15-14.76), and 4.81 (1.35-17.10), and with low muscle strength was (OR (95% CI) for the first, second, and fifth quintiles, respectively: 1.43 (1.16-5.07), 2.07 (1.24-4.70), and 2.18 (1.03-4.60). Additionally, FT3 had a negative association with muscle mass in both age strata.

CONCLUSION

Subtle thyroid hormone alterations are associated with sarcopenia or its defining components in middle-aged and older adults without overt thyroid dysfunction. J Am Geriatr Soc 68:1545-1553, 2020.

Low free T3 to free T4 ratio was associated with low muscle mass and impaired physical performance in community-dwelling aged population

In aged population, the association of thyroid hormones on physical performance, especially within their normal range, has yet to be elucidated. In this study, individuals with low serum free T3/free T4 were likely to have low muscle mass and impaired physical performance.

PURPOSE

We aimed to evaluate the associations of muscle mass, strength, and physical performance with thyroid hormone in an aged euthyroid population from a community-based cohort.

METHODS

We examined 918 men aged over 60 years and 1215 postmenopausal women from the Ansung cohort study. Appendicular skeletal muscle mass divided by square of height (ASM/ht²) was used as the muscle mass index. Hand grip strength was measured using a hydraulic dynamometer. Physical performance was assessed using the short physical performance battery (SPPB).

RESULTS

Participants with higher tertiles of free T3 and free T3/free T4 were younger and had higher ASM/ht², stronger hand grip strength, and higher SPPB scores than those in the lower tertiles. In adjusted models, men within higher tertiles of free T3 had higher ASM/ht² compared with those within lower tertiles (p = 0.033), whereas subjects with higher tertiles of free T4 had lower ASM/ht² compared with those within lower tertiles (p = 0.043). Subjects within higher tertiles of free T3/free T4 had higher ASM/ht² (p < 0.001) and better physical performance (p = 0.048) than those within lower tertiles after adjustments. However, free T3, free T4, or free T3/free T4 was not related to hand grip strength after adjustment for covariates.

CONCLUSION

Our results thus indicate that in an aged euthyroid population, low serum free T3/free T4 was a better index for low muscle mass and impaired physical performance than serum free T3 or free T4 alone.

Association of Thyroid Function with Handgrip Strength: Data from the Study of Health in Pomerania and the Berlin Aging Study II

Background: Untreated overt hypo- and hyperthyroidism can lead to detrimental effects on muscle tissue and physical performance, but it is still unclear whether subclinical hypo- or hyperthyroidism has clinically relevant effects on muscle function and physical performance. The objective of this study was to determine associations of thyrotropin (TSH) with grip strength and physical performance. Methods: A sample of 6196 participants from the Study of Health in Pomerania and the Berlin Aging Study II was included in this cross-sectional analysis. Handgrip strength was measured with a hand-held dynamometer and physical performance was assessed with the timed up and go (TUG) test. Results: Serum TSH levels were significantly inversely associated with handgrip strength (β -0.11; [95% confidence interval, CI, -0.18 to -0.03]; p < 0.05) in multivariable linear regression. Individuals with high (β -1.06; [95% CI -1.86 to -0.26]; p < 0.05) or low (β -0.99; [95% CI -1.70 to -0.28]; p < 0.05) serum TSH levels had a significantly lower handgrip strength than individuals with serum TSH levels within the reference range. There was no association between TSH and the TUG time. Age showed a significant influence on the association of TSH with grip strength and TUG time. Conclusions: Even mild disturbances of thyroid function might lead to a relevant decline in grip strength, particularly in young and middle-aged subjects. Mild subclinical hypothyroidism might not be that unfavorable with regard to physical function in terms of handgrip strength at older age. Further studies are needed to clarify causal relationships.

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.

Gender difference and correlation between sexuality, thyroid hormones, cognitive, and physical functions in elderly fit

PURPOSE

Sexuality in the elderly is related to psycho-physical well-being. Aim of this study was to analyze the correlation between sexual health, thyroid hormones, cognitive functions, and physical fitness in elderly population.

METHODS

Fifty-one fit adults were recruited (age: 71.9 ± 5.3 years, 26 females and 25 males). Sexuality was evaluated using the Changes in Sexual Functioning Questionnaire-short form (CSFQ-14) and the Sexual Attitude Scale (SAS). Thyroid function was assessed by measuring serum TSH, FT3, and FT4. Cognitive functions and depressive symptoms were evaluated by the Mini Mental State Examination (MMSE) test and Geriatric Depression Scale (GDS) scores. Subjects' physical fitness was evaluated using the following tests: Short Physical Performance Battery (SPPB), Handgrip test (HG), Timed Up and Go test (TUG), and 2-Minute step test (ST).

RESULTS

CSFQ-14 positively correlated with MMSE (p < 0.05) and negatively with GDS (p < 0.05), while thyroid function was not correlated with sexuality, in both genders. A negative relationship between FT4 vs. weight, FT3 vs. HG and FT3/FT4 ratio vs. ST were found (p = 0.05) in females, while in males, it occurred for TSH vs. TUG (p < 0.05); a positive relationship existed in females between FT4 vs. ST (p < 0.05). Finally, CSFQ-14 was significantly correlated with SPPB (p < 0.05), CST, TUG, and ST (p < 0.01), in both genders.

CONCLUSION

We demonstrated a strict relationship between active sexuality, preserved cognitive function and appropriate physical fitness in elderly subjects, independently from gender. Our preliminary data suggest that in elderly fit population, peripheral thyroxin deiodination may be a useful predictor of better physical performance and more successful aging.

Physical performance across the thyroid function values within the normal range in adult and older persons

BACKGROUND

Thyroid hormone variation may be correlated with adverse health outcomes, even within the normal reference range in euthyroid individuals.

AIMS

To determine the association between plasma thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels and physical performance score in middle age and older adults who had levels of all three hormones in the normal range.

METHODS

In this community-based, cross-sectional study, euthyroid participants of the Invecchiare in Chianti study, aged 23-102 years (N = 1060), were considered. Physical performance was evaluated by the Summary Physical Performance Battery (SPPB) score. Plasma TSH, FT3, and FT4 levels were predictors, and SPPB score was the outcome.

RESULTS

At the univariate analyses, TSH, FT4, and FT3 were not significantly associated with SPPB score in young individuals, whereas, in older participants, SBBP score was positively (P < 0.001) associated with FT3, and negatively associated with both TSH (P < 0.02) and FT4 (P < 0.001). After adjusting for multiple confounders, FT3 remained significantly associated with SPPB (beta ± SE, 0.35 ± 0.17, P = 0.04), but FT4 and TSH were not. Results did not change when all the three hormones FT3, FT4, and TSH were simultaneously considered in the fully adjusted model (beta ± SE for FT3, 0.37 ± 0.18, P = 0.04).

DISCUSSION

The results of this study demonstrate that SPPB score is positively associated with circulating FT3 but not with FT4 or with TSH, in older euthyroid individuals.

CONCLUSIONS

In euthyroid older adults, circulating FT3 may play an important role in the thyroid effects on physical function.

Clinical aspects of thyroid function during ageing

Globally, populations are ageing at a rapid rate. The increase in the number of older citizens is accompanied by an increased prevalence of thyroid dysfunction, one of the most common disorders in older people. However, the diagnosis of thyroid dysfunction in older people is hindered by several factors, including the scarcity of thyroid dysfunction symptoms in older people. We describe the physiological changes in thyroid function that occur with increasing age, focusing on literature regarding changes in thyroid function test results in older populations. We also discuss treatment considerations for clinical and subclinical thyroid dysfunction according to international guidelines for older people. Finally, we discuss the relationship between variations in thyroid function and common diseases of old age including cardiovascular disease, osteoporosis, cognitive impairment, and frailty and suggest directions for future research.

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 AND AGING

OBJECTIVE

Review physiologic thyroid function changes with aging and emphasize careful interpretation of tests in the aging population.

METHODS

Literature review.

RESULTS

Using age-specific thyroid-stimulating hormone (TSH) reference ranges should minimize or avoid the unnecessary diagnosis of thyroid disease in elderly patients. Subclinical thyroid dysfunction and abnormal TSH with normal thyroid levels may improve with time, so careful monitoring of thyroid function is recommended. Overt thyroid disease should always be treated.

CONCLUSION

Clinical judgement is always warranted to decide how and when to treat subclinical thyroid disease in the elderly.

ABBREVIATIONS

FT4 = free thyroxine; rT3 = reverse triiodothyronine; T3 = triiodothyronine; T4 = thyroxine; TFT = thyroid function test; TSH = thyroid-stimulating hormone.

2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis

BACKGROUND

Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This document describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

METHODS

The American Thyroid Association (ATA) previously cosponsored guidelines for the management of thyrotoxicosis that were published in 2011. Considerable new literature has been published since then, and the ATA felt updated evidence-based guidelines were needed. The association assembled a task force of expert clinicians who authored this report. They examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to update the 2011 text and recommendations. The strength of the recommendations and the quality of evidence supporting them were rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group.

RESULTS

Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' orbitopathy; and management of other miscellaneous causes of thyrotoxicosis. New paradigms since publication of the 2011 guidelines are presented for the evaluation of the etiology of thyrotoxicosis, the management of Graves' hyperthyroidism with antithyroid drugs, the management of pregnant hyperthyroid patients, and the preparation of patients for thyroid surgery. The sections on less common causes of thyrotoxicosis have been expanded.

CONCLUSIONS

One hundred twenty-four evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Multiple hormonal dysregulation as determinant of low physical performance and mobility in older persons

Mobility-disability is a common condition in older individuals. Many factors, including the age-related hormonal dysregulation, may concur to the development of disability in the elderly. In fact, during the aging process it is observed an imbalance between anabolic hormones that decrease (testosterone, dehydroepiandrosterone sulphate (DHEAS), estradiol, insulin like growth factor-1 (IGF-1) and Vitamin D) and catabolic hormones (cortisol, thyroid hormones) that increase. We start this review focusing on the mechanisms by which anabolic and catabolic hormones may affect physical performance and mobility. To address the role of the hormonal dysregulation to mobility-disability, we start to discuss the contribution of the single hormonal derangement. The studies used in this review were selected according to the period of time of publication, ranging from 2002 to 2013, and the age of the participants (≥65 years). We devoted particular attention to the effects of anabolic hormones (DHEAS, testosterone, estradiol, Vitamin D and IGF-1) on both skeletal muscle mass and strength, as well as other objective indicators of physical performance. We also analyzed the reasons beyond the inconclusive data coming from RCTs using sex hormones, thyroid hormones, and vitamin D (dosage, duration of treatment, baseline hormonal values and reached hormonal levels). We finally hypothesized that the parallel decline of anabolic hormones has a higher impact than a single hormonal derangement on adverse mobility outcomes in older population. Given the multifactorial origin of low mobility, we underlined the need of future synergistic optional treatments (micronutrients and exercise) to improve the effectiveness of hormonal treatment and to safely ameliorate the anabolic hormonal status and mobility in older individuals.

Serum thyroid-stimulating hormone levels are not associated with exercise capacity and lung function parameters in two population-based studies

BACKGROUND

Thyroid dysfunction has been described to be linked to a variety of cardiovascular morbidities. Through this pathway thyroid function might also be associated with cardiorespiratory function and exercise capacity. So far only few patient-studies with small study populations investigated the association between thyroid dysfunction and exercise capacity. Thus, the aim of our study was to investigate the association of serum thyroid-stimulating hormone (TSH) levels with lung function and cardiopulmonary exercise testing (CPET) in the general population.

METHODS

Data from the two independent cross-sectional population-based studies (Study of Health in Pomerania [SHIP] and SHIP-Trend-0) were pooled. SHIP was conducted between 2002 and 2006 and SHIP-Trend-0 between 2008 and 2012. Participants were randomly selected from population registries. In total, 4206 individuals with complete data were available for the present analysis. Thyroid function was defined based on serum TSH levels. Lung function was evaluated by forced expiratory volume in 1 s and forced vital capacity. CPET was based on symptom limited exercise tests on a bicycle in a sitting position according to a modified Jones protocol. Associations of serum TSH levels with lung function and CPET parameters were analysed by multivariable quantile regression adjusted for age, sex, height, weight, use of beta blockers, smoking status, and physical activity.

RESULTS

Serum TSH levels, used as continuously distributed variable and categorized according to the clinical cut-offs 0.3 and 3.0 mIU/L or according to quintiles, were not consistently associated with parameters of lung function or CPET.

CONCLUSIONS

Our results suggest that thyroid dysfunction is not associated with lung function and cardiopulmonary exercise capacity in the general population.

An update on subclinical hypothyroidism and subclinical hyperthyroidism

Subclinical thyroid dysfunction is characterized by normal levels of peripheral thyroid hormone, paired with a TSH level that is either lower than (subclinical hyperthyroidism) or higher than (subclinical hypothyroidism) the normal laboratory reference range. Slight shifts in peripheral hormone levels result in significant serum TSH changes. The exact upper limit of normal TSH and the management of subclinical hypothyroidism are still controversial. For those with TSH between high upper limit of normal and 10 mIU/L, the authors suggest selective use of thyroxine therapy. The authors agree with the general consensus in favor of therapy for those with serum TSH levels above 10 mIU/L. This recommendation is compatible with guidelines of American Thyroid Association and American Association of Clinical Endocrinologists. For subclinical hyperthyroidism persistent serum TSH <0.1 mIU/L should be treated particularly if the etiology is nodular toxic goiter. For serum TSH between 0.1 mIU/L and lower limit of normal, serum TSH co-morbidities such as cardiac risk factors and osteoporosis may favor therapy.

Thyroid status and 6-year mortality in elderly people living in a mildly iodine-deficient area: the aging in the Chianti Area Study

OBJECTIVES

To test the hypothesis that, in older adults, living in a mildly iodine-deficient area, thyroid dysfunction may be associated with mortality independent of potential confounders.

DESIGN

Longitudinal.

SETTING

Community-based.

PARTICIPANTS

Nine hundred fifty-one individuals aged 65 and older.

MEASUREMENTS

Plasma thyrotropin, free thyroxine, and free triiodothyronine concentrations and demographic features were evaluated in participants of the Invecchiare in Chianti Study aged 65 and older. Participants were classified according to thyroid function test. Kaplan-Meier survival and Cox proportional hazards models adjusted for confounders were used in the analysis.

RESULTS

Eight hundred nineteen participants were euthyroid, 83 had subclinical hyperthyroidism (SHyper), and 29 had subclinical hypothyroidism (SHypo). Overt hypo- and hyperthyroidism were found in five and 15 subjects, respectively. During a median of 6 years of follow-up, 210 deaths occurred (22.1%), 98 (46.6%) of which were from cardiovascular causes. Kaplan-Meier analysis revealed higher overall mortality for SHyper (P = .04) than euthyroid subjects. After adjusting for multiple confounders, participants with SHyper (hazard ratio (HR) = 1.65, 95% confidence interval (CI) = 1.02-2.69) had significantly higher all-cause mortality than those with normal thyroid function. No significant association was found between SHyper and cardiovascular mortality. In euthyroid subjects, thyrotropin was found to be predictive of lower risk of all-cause mortality (HR = 0.76, 95% CI = 0.57-0.99).

CONCLUSION

SHyper is an independent risk factor for all-cause mortality in older adults. Low to normal circulating thyrotropin should be carefully monitored in elderly euthyroid individuals.

Thyroid disorders in older adults

This article summarizes the current literature about serum thyroid parameters and thyroid disease during aging. Changes in thyroid function tests may be part of the physiology of aging, after exclusion of confounding variables. Overt thyroid disease requires immediate treatment. Treatment of subclinical hyperthyroidism in the elderly can be advocated, while watchful waiting may be an appropriate approach for subclinical hypothyroidism.

Thyroid dysfunction in the elderly

Thyroid dysfunction is common in the general population, and mild or subclinical forms can be present in more than 10% of individuals aged >80 years. The diagnosis of abnormal thyroid hormone concentrations in people aged >60 years poses a challenge, as the clinical presentation of thyroid dysfunction is usually nonspecific, and ageing is associated with a number of physiological changes that can affect thyroid function test results. Furthermore, the presence of acute or chronic nonthyroidal illnesses and the use of medications that interfere with thyroid function tests are common confounders in the determination of thyroid status in the elderly. Early diagnosis and treatment of overt thyroid dysfunction is crucial in this population in view of the marked effects of abnormal circulating thyroid hormone levels on a number of organ systems, including the heart, the skeleton and the neurological system. The clinical significance of mild thyroid overactivity and underactivity remains uncertain, and the need for treatment of subclinical thyroid dysfunction is much debated. A number of large epidemiological studies have identified associations between mild thyroid dysfunction and short-term as well as long-term adverse outcomes, and a small but increasing number of randomized controlled intervention studies have been reported. Guidelines recommend treatment of thyroid dysfunction on the basis of the degree of abnormal serum TSH concentrations, patient age and associated comorbidities. This Review describes the current evidence on the prevalence, diagnosis, management and long-term consequences of thyroid dysfunction in the elderly.

Thyroid hormones as predictors of short- and long-term mortality in very old hospitalized patients

BACKGROUND

Although extensively investigated, the prognostic role of thyroid hormone abnormalities in older participants remains uncertain. We investigated the relationship between thyroid hormones and mortality during hospitalization and in a prolonged follow-up in frail older patients.

METHODS

A nonconcurrent cohort study was conducted by enrolling 450 participants hospitalized for an acute disease, who were classified into four groups (euthyroidism, hypothyroidism, hyperthyroidism, and low triiodothyronine [T3] syndrome), according to clinical and laboratory data. Multidimensional geriatric assessment variables were considered in order to identify short- and long-term predictors of death.

RESULTS

Participants were very old (mean age: 84 years) and frail, as indicated by severely impaired functional status, extensive comorbidity, high prevalence of dementia, and hospital mortality (8%). Prevalence of any thyroid dysfunction was 40.7%; 32% of participants had low T3 syndrome, which was associated with an excess hospital mortality risk (odds ratio: 2.7, 95% confidence interval [CI]: 1.1-6.5; p = .025), adjusted for demographic, clinical, functional, and laboratory data. Conversely, long-term mortality was unrelated to low T3 syndrome. In euthyroid participants, increasing levels of free thyroxine (FT4) were associated with a slightly greater mortality (hazard ratio, CI: 2.12, 0.99-4.54; p = .053) in adjusted Cox regression models.

CONCLUSIONS

This observational study on a cohort of very old, frail hospitalized patients gives support to the independent prognostic short-term, but not long-term, role of low T3 syndrome. Moreover, in older euthyroid participants, increasing levels of FT4 are a weak marker of poorer long-term survival. Thyroid hormones may help monitor changes in general health status and predict short- and long-term clinical outcomes in very old, frail patients.