Subclinical thyroid dysfunction and the risk of heart failure events: an individual participant data analysis from 6 prospective cohorts.

BACKGROUND: American College of Cardiology/American Heart Association guidelines for the diagnosis and management of heart failure recommend investigating exacerbating conditions such as thyroid dysfunction, but without specifying the impact of different thyroid-stimulation hormone (TSH) levels. Limited prospective data exist on the association between subclinical thyroid dysfunction and heart failure events. METHODS AND RESULTS: We performed a pooled analysis of individual participant data using all available prospective cohorts with thyroid function tests and subsequent follow-up of heart failure events. Individual data on 25 390 participants with 216 248 person-years of follow-up were supplied from 6 prospective cohorts in the United States and Europe. Euthyroidism was defined as TSH of 0.45 to 4.49 mIU/L, subclinical hypothyroidism as TSH of 4.5 to 19.9 mIU/L, and subclinical hyperthyroidism as TSH <0.45 mIU/L, the last two with normal free thyroxine levels. Among 25 390 participants, 2068 (8.1%) had subclinical hypothyroidism and 648 (2.6%) had subclinical hyperthyroidism. In age- and sex-adjusted analyses, risks of heart failure events were increased with both higher and lower TSH levels (P for quadratic pattern <0.01); the hazard ratio was 1.01 (95% confidence interval, 0.81-1.26) for TSH of 4.5 to 6.9 mIU/L, 1.65 (95% confidence interval, 0.84-3.23) for TSH of 7.0 to 9.9 mIU/L, 1.86 (95% confidence interval, 1.27-2.72) for TSH of 10.0 to 19.9 mIU/L (P for trend <0.01) and 1.31 (95% confidence interval, 0.88-1.95) for TSH of 0.10 to 0.44 mIU/L and 1.94 (95% confidence interval, 1.01-3.72) for TSH <0.10 mIU/L (P for trend=0.047). Risks remained similar after adjustment for cardiovascular risk factors. CONCLUSION: Risks of heart failure events were increased with both higher and lower TSH levels, particularly for TSH ≥10 and <0.10 mIU/L.

Differential gene expression analysis of iodide-treated rat thyroid follicular cell line PCCl3

The inhibitory effect of supraphysiological iodide concentrations on thyroid hormone synthesis (Wolff - Chaikoff effect) and on thyrocyte proliferation is largely known as iodine autoregulation. However, the molecular mechanisms by which iodide modulates thyroid function remain unclear. In this paper, we analyze the transcriptome profile of the rat follicular cell lineage PCCl3 under untreated and treated conditions with 10 (- 3) M sodium iodide (NaI). Serial analysis of gene expression (SAGE) revealed 84 transcripts differentially expressed in response to iodide (p <= 0.001). We also showed that iodide excess inhibits the expression of essential genes for thyroid differentiation: Tshr, Nis, Tg, and Tpo. Relative expression of 14 of 20 transcripts selected by SAGE was confirmed by real-time PCR. Considering the key role of iodide organification in thyroid physiology, we also observed that both the oxidized form of iodide and iodide per se are responsible for gene expression modulation in response to iodide excess. (c) 2008 Elsevier Inc. All rights reserved.

Effects of gonadectomy on prolactin and LH secretion and the pituitary-thyroid axis in male dogs

The effects of gonadectomy on the secretion of prolactin, LH, TSH, and thyroxine were investigated. Blood serum hormone concentrations were analysed before and at 20, 120, and 180 min after a single iv TRH injection in each of eight healthy intact and castrated male beagle dogs before (control) and after 4-week treatment with the dopamine-2 receptor agonist cabergoline. Under control conditions the mean prolactin, TSH, and thyroxine concentrations were similar in intact and gonadectomised dogs, and administration of TRH provoked a significant (p < 0.01) increase in concentrations of the three hormones. The overall inhibitory effect of cabergoline treatment on prolactin secretion was more pronounced in the castrated dogs compared with the intact group. Cabergoline significantly suppressed the TRH-induced prolactin increase in each group (p < 0.01). Corresponding TRH-stimulated TSH concentrations were not affected by cabergoline. In the gonadectomised dogs, thyroxine concentrations before and at 120 and 180 min after TRH injection were significantly lower than under control conditions. LH concentrations were always higher (p < 0.01) in gonadectomised dogs compared with the intact dogs, but appeared to be affected neither by TRH nor by cabergoline administration. It can thus be concluded from the results, that gonadectomy does not result in hyperprolactinaemia in male dogs, while LH concentrations are significantly increased due to missing androgen feedback. Thyroid function remains unaffected by gonadectomy. Testicular steroids appear to interact with central dopaminergic and probably other neuroendocrine mechanisms regulating the secretion of prolactin, TSH, and thyroxine. Thus, long-term dopamine-2 receptor agonistic treatment may lead to a hypothyroid condition in castrated male dogs. (c) 2009 Elsevier B.V. All rights reserved.

Do Thyroid Ultrasonographic Features Change According to Age in Euthyroid Dogs?

The thyroid gland was assessed by ultrasound in healthy euthyroid mixed-breed medium size dogs in different age groups. The objective was to verify ultrasonographic imaging patterns in these groups, as well as to identify possible changes in imaging features resulting from ageing. Thirty dogs - 10 young (<1 year), 10 adult and 10 elderly - without clinical signs or history of thyroid gland disease with complete blood count and thyroid function tests within the reference values were evaluated. Each thyroid lobe was examined by ultrasound for shape, size, echogenicity and echotexture. The analysis of echogenicity and echotexture was made by histogram. Thyroid volume was estimated by the equation for ellipsoid (length x width x height) pi/6. The thyroid volume of the young dogs in this study had a tendency to be higher than in adult dogs (P = 0.068) and older dogs (P = 0.120). The height of the thyroid lobe in the longitudinal plane was significantly higher (P = 0.026) in young dogs compared with the other dogs. The echotexture and echogenicity had no significant differences between groups, but the echogenicity was greater in older dogs. The results point out that ultrasound imaging of the thyroid volume is influenced by age in euthyroid dogs.

Circulating thyroid hormone levels in young pregnant rats and their fetuses: Effect of malnutrition

In order to evaluate some factors likely to be involved in the maternal and fetal growth impairment due to alimentary protein deficiency, the circulating levels of triiodothyronine (T 3) and thyroxine (T 4) were studied in 4 young (45-day-old) female rat groups: control and malnourished, both nonpregnant and pregnant; similarly schedules groups were studied using adult (100-day-old) rats. Circulating levels of T 4 were higher in nonpregnant, malnourished young rats in their corresponding controls. T 3 levels were higher in young malnourished animals and lower in adult malnourished animals, nonpregnant or pregnant, as compared to controls. Pups from young malnourished mothers showed significantly lower birth weights than those from controls. The present results suggest that there are age differences in thyroid function, as affected by protein-calorie malnutrition in pregnant and non-pregnant rats. On the other hand, the circulating thyroid hormone levels were not importantly affected by the mother dietary protein restriction under our experimental conditions.

Sympathetic nervous system activity in rat thyroid: potential role in goitrogenesis

The role of sympathetic innervation in regulation of thyroid function is incompletely understood. We, therefore, carried out studies in rats utilizing techniques of norepinephrine turnover to assess thyroid sympathetic activity in vivo. Thyroidal sympathetic activity was increased 95% by exposure to cold (4 degrees C), 42% by chronic ingestion of an iodine-deficient diet, and 32% in rats fed a goitrogenic diet (low-iodine diet supplemented with propylthiouracil). In addition, fasting for 2 days reduced sympathetic nervous system activity in thyroid by 38%. Thyroid growth and 125I uptake were also compared in intact and decentralized hemithyroids obtained from animals subjected to unilateral superior cervical ganglion decentralization. Unilateral superior cervical ganglion decentralization led to a reduction in thyroid weight, in 125I uptake by thyroid tissue, and in TSH-induced stimulation of 125I uptake in decentralized hemithyroids. These results suggest that sympathetic activity in thyroid contributes to gland enlargement and may modulate tissue responsiveness to TSH.

Subclinical thyroid dysfunction and functional capacity among elderly

Background: Subclinical thyroid dysfunction is common among older people and has been associated with decreased functional capacity but with conflicting data. The aim of this study was to assess the association between subclinical thyroid dysfunction and functional capacity in an elderly population. Methods: We included 5182 participants with a mean age of 75.2 years from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). Self-reported functional capacity was assessed using the Barthel Index (BI) and the Instrumental Activities of Daily Living (IADL) scores at baseline and during follow-up. Participants with subclinical hyperthyroidism (n=65) and subclinical hypothyroidism (n=173) were compared to euthyroid participants (n=4944). The association between persistent subclinical thyroid dysfunction and functional capacity and decline was also investigated. Results: At baseline, compared to euthyroid participants (BI 19.73±SE 0.06; IADL 13.52±0.02), there was no difference in functional capacity for participants with subclinical hyperthyroidism (BI 19.60±0.09; IADL 13.51±0.12, p>0.05) or subclinical hypothyroidism (BI 19.82±0.06; IADL 13.55±0.08, p>0.05). Over a mean 3.2-year follow-up period, there was no association between thyroid function and annual decline of either BI or IADL (p>0.05). No association was found between persistent subclinical thyroid dysfunction and functional capacity at baseline or during follow-up (p>0.05). Results were similar after excluding participants with a maximum BI and/or IADL score at baseline. Conclusion: Among well-functioning community-dwelling elderly, we found no evidence that subclinical thyroid dysfunction contributes to decreased functional capacity.

Subclinical thyroid dysfunction and cognitive decline in old age

BACKGROUND Subclinical thyroid dysfunction has been implicated as a risk factor for cognitive decline in old age, but results are inconsistent. We investigated the association between subclinical thyroid dysfunction and cognitive decline in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). METHODS Prospective longitudinal study of men and women aged 70-82 years with pre-existing vascular disease or more than one risk factor to develop this condition (N = 5,154). Participants taking antithyroid medications, thyroid hormone supplementation and/or amiodarone were excluded. Thyroid function was measured at baseline: subclinical hyper- and hypothyroidism were defined as thyroid stimulating hormones (TSH) <0.45 mU/L or >4.50 mU/L respectively, with normal levels of free thyroxine (FT4). Cognitive performance was tested at baseline and at four subsequent time points during a mean follow-up of 3 years, using five neuropsychological performance tests. RESULTS Subclinical hyperthyroidism and hypothyroidism were found in 65 and 161 participants, respectively. We found no consistent association of subclinical hyper- or hypothyroidism with altered cognitive performance compared to euthyroid participants on the individual cognitive tests. Similarly, there was no association with rate of cognitive decline during follow-up. CONCLUSION We found no consistent evidence that subclinical hyper- or hypothyroidism contribute to cognitive impairment or decline in old age. Although our data are not in support of treatment of subclinical thyroid dysfunction to prevent cognitive dysfunction in later life, only large randomized controlled trials can provide definitive evidence.

Thyroid antibody status, subclinical hypothyroidism, and the risk of coronary heart disease: an individual participant data analysis.

CONTEXT Subclinical hypothyroidism has been associated with increased risk of coronary heart disease (CHD), particularly with thyrotropin levels of 10.0 mIU/L or greater. The measurement of thyroid antibodies helps predict the progression to overt hypothyroidism, but it is unclear whether thyroid autoimmunity independently affects CHD risk. OBJECTIVE The objective of the study was to compare the CHD risk of subclinical hypothyroidism with and without thyroid peroxidase antibodies (TPOAbs). DATA SOURCES AND STUDY SELECTION A MEDLINE and EMBASE search from 1950 to 2011 was conducted for prospective cohorts, reporting baseline thyroid function, antibodies, and CHD outcomes. DATA EXTRACTION Individual data of 38 274 participants from six cohorts for CHD mortality followed up for 460 333 person-years and 33 394 participants from four cohorts for CHD events. DATA SYNTHESIS Among 38 274 adults (median age 55 y, 63% women), 1691 (4.4%) had subclinical hypothyroidism, of whom 775 (45.8%) had positive TPOAbs. During follow-up, 1436 participants died of CHD and 3285 had CHD events. Compared with euthyroid individuals, age- and gender-adjusted risks of CHD mortality in subclinical hypothyroidism were similar among individuals with and without TPOAbs [hazard ratio (HR) 1.15, 95% confidence interval (CI) 0.87-1.53 vs HR 1.26, CI 1.01-1.58, P for interaction = .62], as were risks of CHD events (HR 1.16, CI 0.87-1.56 vs HR 1.26, CI 1.02-1.56, P for interaction = .65). Risks of CHD mortality and events increased with higher thyrotropin, but within each stratum, risks did not differ by TPOAb status. CONCLUSIONS CHD risk associated with subclinical hypothyroidism did not differ by TPOAb status, suggesting that biomarkers of thyroid autoimmunity do not add independent prognostic information for CHD outcomes.

Subclinical thyroid dysfunction and the risk for fractures: a systematic review and meta-analysis.

BACKGROUND Data on the association between subclinical thyroid dysfunction and fractures conflict. PURPOSE To assess the risk for hip and nonspine fractures associated with subclinical thyroid dysfunction among prospective cohorts. DATA SOURCES Search of MEDLINE and EMBASE (1946 to 16 March 2014) and reference lists of retrieved articles without language restriction. STUDY SELECTION Two physicians screened and identified prospective cohorts that measured thyroid function and followed participants to assess fracture outcomes. DATA EXTRACTION One reviewer extracted data using a standardized protocol, and another verified data. Both reviewers independently assessed methodological quality of the studies. DATA SYNTHESIS The 7 population-based cohorts of heterogeneous quality included 50,245 participants with 1966 hip and 3281 nonspine fractures. In random-effects models that included the 5 higher-quality studies, the pooled adjusted hazard ratios (HRs) of participants with subclinical hyperthyroidism versus euthyrodism were 1.38 (95% CI, 0.92 to 2.07) for hip fractures and 1.20 (CI, 0.83 to 1.72) for nonspine fractures without statistical heterogeneity (P = 0.82 and 0.52, respectively; I2= 0%). Pooled estimates for the 7 cohorts were 1.26 (CI, 0.96 to 1.65) for hip fractures and 1.16 (CI, 0.95 to 1.42) for nonspine fractures. When thyroxine recipients were excluded, the HRs for participants with subclinical hyperthyroidism were 2.16 (CI, 0.87 to 5.37) for hip fractures and 1.43 (CI, 0.73 to 2.78) for nonspine fractures. For participants with subclinical hypothyroidism, HRs from higher-quality studies were 1.12 (CI, 0.83 to 1.51) for hip fractures and 1.04 (CI, 0.76 to 1.42) for nonspine fractures (P for heterogeneity = 0.69 and 0.88, respectively; I2 = 0%). LIMITATIONS Selective reporting cannot be excluded. Adjustment for potential common confounders varied and was not adequately done across all studies. CONCLUSION Subclinical hyperthyroidism might be associated with an increased risk for hip and nonspine fractures, but additional large, high-quality studies are needed. PRIMARY FUNDING SOURCE Swiss National Science Foundation.

Subclinical thyroid dysfunction and the risk of stroke: a systematic review and meta-analysis

Subclinical thyroid dysfunction has been associated with coronary heart disease, but the risk of stroke is unclear. Our aim is to combine the evidence on the association between subclinical thyroid dysfunction and the risk of stroke in prospective cohort studies. We searched Medline (OvidSP), Embase, Web-of-Science, Pubmed Publisher, Cochrane and Google Scholar from inception to November 2013 using a cohort filter, but without language restriction or other limitations. Reference lists of articles were searched. Two independent reviewers screened articles according to pre-specified criteria and selected prospective cohort studies with baseline thyroid function measurements and assessment of stroke outcomes. Data were derived using a standardized data extraction form. Quality was assessed according to previously defined quality indicators by two independent reviewers. We pooled the outcomes using a random-effects model. Of 2,274 articles screened, six cohort studies, including 11,309 participants with 665 stroke events, met the criteria. Four of six studies provided information on subclinical hyperthyroidism including a total of 6,029 participants and five on subclinical hypothyroidism (n = 10,118). The pooled hazard ratio (HR) was 1.08 (95 % CI 0.87-1.34) for subclinical hypothyroidism (I (2) of 0 %) and 1.17 (95 % CI 0.54-2.56) for subclinical hyperthyroidism (I (2) of 67 %) compared to euthyroidism. Subgroup analyses yielded similar results. Our systematic review provides no evidence supporting an increased risk for stroke associated with subclinical thyroid dysfunction. However, the available literature is insufficient and larger datasets are needed to perform extended analyses. Also, there were insufficient events to exclude clinically significant risk from subclinical hyperthyroidism, and more data are required for subgroup analyses.

Subclinical thyroid dysfunction and fracture risk: a meta-analysis.

IMPORTANCE Associations between subclinical thyroid dysfunction and fractures are unclear and clinical trials are lacking. OBJECTIVE To assess the association of subclinical thyroid dysfunction with hip, nonspine, spine, or any fractures. DATA SOURCES AND STUDY SELECTION The databases of MEDLINE and EMBASE (inception to March 26, 2015) were searched without language restrictions for prospective cohort studies with thyroid function data and subsequent fractures. DATA EXTRACTION Individual participant data were obtained from 13 prospective cohorts in the United States, Europe, Australia, and Japan. Levels of thyroid function were defined as euthyroidism (thyroid-stimulating hormone [TSH], 0.45-4.49 mIU/L), subclinical hyperthyroidism (TSH <0.45 mIU/L), and subclinical hypothyroidism (TSH ≥4.50-19.99 mIU/L) with normal thyroxine concentrations. MAIN OUTCOME AND MEASURES The primary outcome was hip fracture. Any fractures, nonspine fractures, and clinical spine fractures were secondary outcomes. RESULTS Among 70,298 participants, 4092 (5.8%) had subclinical hypothyroidism and 2219 (3.2%) had subclinical hyperthyroidism. During 762,401 person-years of follow-up, hip fracture occurred in 2975 participants (4.6%; 12 studies), any fracture in 2528 participants (9.0%; 8 studies), nonspine fracture in 2018 participants (8.4%; 8 studies), and spine fracture in 296 participants (1.3%; 6 studies). In age- and sex-adjusted analyses, the hazard ratio (HR) for subclinical hyperthyroidism vs euthyroidism was 1.36 for hip fracture (95% CI, 1.13-1.64; 146 events in 2082 participants vs 2534 in 56,471); for any fracture, HR was 1.28 (95% CI, 1.06-1.53; 121 events in 888 participants vs 2203 in 25,901); for nonspine fracture, HR was 1.16 (95% CI, 0.95-1.41; 107 events in 946 participants vs 1745 in 21,722); and for spine fracture, HR was 1.51 (95% CI, 0.93-2.45; 17 events in 732 participants vs 255 in 20,328). Lower TSH was associated with higher fracture rates: for TSH of less than 0.10 mIU/L, HR was 1.61 for hip fracture (95% CI, 1.21-2.15; 47 events in 510 participants); for any fracture, HR was 1.98 (95% CI, 1.41-2.78; 44 events in 212 participants); for nonspine fracture, HR was 1.61 (95% CI, 0.96-2.71; 32 events in 185 participants); and for spine fracture, HR was 3.57 (95% CI, 1.88-6.78; 8 events in 162 participants). Risks were similar after adjustment for other fracture risk factors. Endogenous subclinical hyperthyroidism (excluding thyroid medication users) was associated with HRs of 1.52 (95% CI, 1.19-1.93) for hip fracture, 1.42 (95% CI, 1.16-1.74) for any fracture, and 1.74 (95% CI, 1.01-2.99) for spine fracture. No association was found between subclinical hypothyroidism and fracture risk. CONCLUSIONS AND RELEVANCE Subclinical hyperthyroidism was associated with an increased risk of hip and other fractures, particularly among those with TSH levels of less than 0.10 mIU/L and those with endogenous subclinical hyperthyroidism. Further study is needed to determine whether treating subclinical hyperthyroidism can prevent fractures.

Subclinical Thyroid Dysfunction and Depressive Symptoms among Elderly: A Prospective Cohort Study

BACKGROUND Subclinical hypothyroidism has been associated with depressive symptoms in cross-sectional studies, but prospective data and data on subclinical hyperthyroidism are scarce. METHODS In the Leiden sub-study of the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) among adults aged 70-82 years with pre-existing cardiovascular disease or known cardiovascular risk factors, TSH and free T4 levels were measured at baseline and repeated after 6 months to define persistent thyroid function status. Main outcome measures were depressive symptoms, assessed with the Geriatric Depression Scale 15 (GDS) at baseline and after 3 years. All analyses were adjusted for age, gender and education. RESULTS Among 606 participants (41% women, mean age 75 years) without anti-depressant medication, GDS scores at baseline did not differ for participants with subclinical hypothyroidism (n = 47; GDS 1.75, 95% CI 1.29-2.20, p = 0.50) or subclinical hyperthyroidism (n = 13; GDS 1.64 [0.78-2.51], p = 1.00) compared to euthyroid participants (n = 546, mean GDS 1.60 [1.46-1.73]). After 3 years, compared to euthyroid participants, change in GDS scores did not differ for participants with subclinical hypothyroidism (ΔGDS -0.03 [-0.50-0.44], p = 0.80), while subclinical hyperthyroidism was associated with an increase in GDS scores (ΔGDS 1.13 [0.32-1.93] p = 0.04). All results were similar for persistent subclinical thyroid dysfunction. CONCLUSIONS In this largest prospective study on the association of persistent subclinical thyroid dysfunction and depression, subclinical hypothyroidism was not associated with increased depressive symptoms among older adults at high cardiovascular risk. Persistent subclinical hyperthyroidism might be associated with increased depressive symptoms, which requires confirmation in a larger prospective study. © 2015 S. Karger AG, Basel.

Thyroid dysfunction and anemia in a large population-based study.

OBJECTIVE AND BACKGROUND Anemia and thyroid dysfunction are common and often co-occur. Current guidelines recommend the assessment of thyroid function in the work-up of anemia, although evidence on this association is scarce. PATIENTS AND METHODS In the "European Prospective Investigation of Cancer" (EPIC)-Norfolk population-based cohort, we aimed to examine the prevalence and type of anemia (defined as hemoglobin <13 g/dl for men and <12 g/dl for women) according to different thyroid function groups. RESULTS The mean age of the 8791 participants was 59.4 (SD 9.1) years and 55.2% were women. Thyroid dysfunction was present in 437 (5.0%) and anemia in 517 (5.9%) participants. After excluding 121 participants with three most common causes of anemia (chronic kidney disease, inflammation, iron deficiency), anemia was found in 4.7% of euthyroid participants. Compared with the euthyroid group, the prevalence of anemia was significantly higher in overt hyperthyroidism (14.6%, P < .01), higher with borderline significance in overt hypothyroidism (7.7%, P = .05) and not increased in subclinical thyroid dysfunction (5.0% in subclinical hypothyroidism, 3.3% in subclinical hyperthyroidism). Anemia associated with thyroid dysfunction was mainly normocytic (94.0%), and rarely macrocytic (6.0%). CONCLUSION The prevalence of anemia was higher in overt hyperthyroidism, but not increased in subclinical thyroid dysfunction. Systematic measurement of thyroid-stimulating hormone in anemic patients is likely to be useful only after excluding common causes of anemia.

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.