Association between Free Triiodothyronine Levels and Peripheral Arterial Disease in Euthyroid Participants

这当前的代表性的研究 40 年并且在上面在 euthyroid 汉语人口之中调查在甲状腺荷尔蒙和外部动脉疾病(垫) 之间的关系。浆液免费 triiodothyronine (FT3 ) ，免费甲状腺素(FT4 ) ，刺激甲状腺的荷尔蒙(TSH ) ，和甲状腺抗体被测量。垫被定义为脚关节臂的索引(ABI )< 0.9。有 91 (2.9%) 在 3,148 euthyroid 之中的垫案例学习参加者。参加者在有的 FT3 和 free-triiodothyronine-to-free-thyroxin (FT3/FT4 比率) 最高方照流行的垫的减少的风险(调整 multivariate 的机会比率， 95% 信心间隔：0.32， 0.15-0.62，为趋势 = 的 P 0.01 和 0.31， 0.13-0.66，为趋势 = 的 P 0.004，分别地) 与那些相比在里面最低方照。得出结论， FT3 层次和 FT3/FT4 比率相反地 40 年并且在上面在 euthyroid 汉语人口与流行的垫被联系。

Triiodothyronine and breast cancer

The thyroid hormones(THs), triiodothyronine(T3) and thyroxine(T4), are essential for survival; they are involved in the processes of development, growth, and metabolism. In addition to hyperthyroidism or hypothyroidism, THs are involved in other diseases. The role of THs in the development and differentiation of mammary epithelium is well established; however, their specific role in the pathogenesis of breast cancer(BC) is controversial. Steroid hormones affect many human cancers and the abnormal responsiveness of the mammary epithelial cells to estradiol(E2) in particular is known to be an important cause for the development and progression of BC. The proliferative effect of T3 has been demonstrated in various types of cancer. In BC cell lines, T3 may foster the conditions for tumor proliferation and increase the effect of cell proliferation by E2; thus, T3 may play a role in the developmentand progression of BC. Studies show that T3 has effects similar to E2 in BC cell lines. Despite controversy regarding the relationship between thyroid disturbances and the incidence of BC, studies show that thyroid status may influence the development of tumor, proliferation and metastasis.

Free triiodothyronine in relation to coronary severity at different ages： Gensini score assessment in 4206 euthyroid patients

为了学习在正常范围以内的免费 triiodothyronine ( FT3 )是否在不同的性和年龄 groups.MethodsA 在冠的动脉疾病( CAD )的存在和严厉上有效果， 4206 个 euthyroid 病人总计连续地被注册并且把组划分了成 CAD ( n = 3306 )并且 非CAD 组( n = 900 )。所有病人经历了冠的 angiography (CAG ) 。Gensini 分数(GS ) 被用来决定冠的动脉狭窄的严厉。严重 CAD 被定义为 GS > 32 并且温和 CAD 被定义为 GS 32。逻辑回归分析和线性回归分析被进行与不同的性在病人与 CAD 决定 FT3 的协会， FT3 的 ages.ResultsConcentration 在 angiography 正常的控制组比那在有 CAD 的病人是更低的(P < 0.05 ) 。另外， FT3 的集中在温和 CAD 比那在严重 CAD 是更低的。在为传统的心血管的风险因素和潜在的 confounders 调整以后， FT3 否定地与 CAD 的存在被相关，然而并非在老病人(> 65 岁) 。Multivariable 线性回归分析证明 FT3 否定地在正常以内与稳定的 CAD 在男、年轻的病人，然而并非在旧 patients.ConclusionsLow FT3 与 GS 被联系范围否定地在年轻病人，然而并非在旧的与 CAD 的存在和严厉被联系。进一步的研究被需要证实我们的调查结果。

Prognostic value of free triiodothyronine in patients with dilated cardiomyopathy

Background:The association between free triiodothyronine(FT3)and long-term prognosis in dilated cardiomyopathy(DCM)patients has not been evaluated.The purpose of this study was to determine whether the level of FT3 could provide prognostic value in patients with DCM.Methods:Data of consecutive patients diagnosed with DCM were collected from October 2009 to December 2014.FT3 was measured by fluoroimmunoassay.Other biochemical markers,such as free thyroxin(FT4),thyroid-stimulating hormone,red blood cell,hemoglobin,blood urea nitrogen,and serum creatinine,were tested at the same time.Follow-up was performed every 3 months.The primary endpoint was all-cause mortality.Pearson analysis was used to evaluate the correlation of FT3 and other lab metrics with DCM patients’prognosis.The association of long-term mortality in DCM and FT3 was compared using Cox hazards model.Results:Data of 176 patients diagnosed with DCM were collected.Of them,24 patients missed FT3 values and six patients were lost to follow-up.Altogether,data of 146 patients were analyzed.During the median follow-up time of 79.9(53.5-159.6)months,nine patients lost,61 patients died(non-survival group),and 85 patients survived(survival group).FT3 was significantly lower in non-survival group than that in survival group(3.65±0.83 pmol/L vs.4.36±1.91 pmol/L;P=0.003).FT3 also showed a significantly positive correlation with red blood cell and hemoglobin,negatively correlated with age,blood urea nitrogen and serum creatinine(P<0.05),respectively.Patients in the group of lower FT3 levels(FT3≤3.49 pmol/L)suffered from a higher risk of all-cause mortality(P for log-rank=0.001).In multivariate Cox regression analysis,FT3 level was significantly associated with all-cause mortality(hazard ratio:0.70,95%confidence interval 0.52-0.95,P for trend=0.021).Conclusion:Low levels of FT3 were associated with increased all-cause mortality in patients with DCM.

Thyroid peroxidase antibody positivity and triiodothyronine levels are associated with pediatric Graves'ophthalmopathy

Background:Graves'ophthalmopathy(GO)occurs commonly in children with Graves'disease(GD).However,there are limited studies on the clinical manifestations and thyroid autoantibodies in pediatric GO.The aim of this study was to investigate the prevalence and risk factors of GO in childhood GD.Methods:Clinical and biochemical data from children and adolescents with GD were retrospectively reviewed.Eighty patients under 19 years of age were included in the present study.We compared the clinical and biochemical differences between patients with and without GO.Results:Thirty-nine percent of the patients had GO,and 81%of the GO patients were females.Of these,two patients showed unilateral GO.Triiodothyronine(T3)levels were higher in GO patients than in those without GO.Anti-thyroglobulin antibody and thyroid stimulating hormone receptor antibody titers were not significantly different between the two groups.Anti-thyroid peroxidase antibody(TPO Ab)positivity was 68%in the patients with GO and only 47%in the patients without GO.In multivariate regression analysis,high T3 levels and TPO Ab positivity were related to the presence of GO.Conclusion:In children and adolescents with GD,TPO Ab positivity and high T3 levels could act as predictive factors for the presence of GO.

Association of Serum Ferritin Levels and Thyroid Hormones

Thyroid metabolism is orchestrated by the action of various minerals and trace elements including iron, iodine, selenium, and zinc. Iron deficiency, specifically deficiency in serum ferritin levels, is one of the common causes of thyroid dysfunction. Our objective was to evaluate the relationship between serum ferritin levels and circulating thyroid hormones. For this, a retrospective analysis was performed on 16,512 individuals who tested for serum levels of ferritin and thyroid profile at Vibrant America Clinical Laboratories. Subjects were stratified based on the serum levels of ferritin. Age (p −0.03232, p < 0.0001). Analysis of Linear association by Pearson’s correlation exhibited a considerable correlation between varying serum ferritin levels with all tested thyroid hormones. The study concludes that serum ferritin levels were associated with thyroid hormone synthesis and metabolism in individuals with optimal levels of circulating ferritin.

Relationship between β-amyloid protein 1-42, thyroid hormone levels and the risk of cognitive impairment after ischemic stroke

BACKGROUND Post-stroke cognitive impairment(PSCI)is not only a common consequence of stroke but also an important factor for adverse prognosis of patients.Biochemical indicators such as blood lipids and blood pressure are affected by many factors,and the ability of evaluating the progress of patients with PSCI is insufficient.Therefore,it is necessary to find sensitive markers for predicting the progress of patients and avoiding PSCI.Recent studies have shown thatβ-amyloid protein 1-42(Aβ1-42)and thyroid hormone levels are closely related to PSCI,which may be the influencing factors of PSCI,but there are few related studies.AIM To investigate the relationship between serum levels of Aβand thyroid hormones in acute stage and PSCI and its predicted value.METHODS A total of 195 patients with acute cerebral infarction confirmed from June 2016 to January 2018 were enrolled in this study.Baseline data and serological indicators were recorded to assess cognitive function of patients.All patients were followed up for 1 year.Their cognitive functions were evaluated within 1 wk,3 mo,6 mo and 1 yr after stroke.At the end of follow-up,the patients were divided into PSCI and non-PSCI according to Montreal cognitive assessment score,and the relationship between biochemical indexes and the progression of PSCI was explored.RESULTS Compared with patients with non-PSCI,the levels of Aβ1-42,triiodothyronine(T3)and free thyroxin were lower in the patients with PSCI.Repeated measures analysis of variance showed that the overall content of Aβ1-42 and T3 in PSCI was also lower than that of the non-PSCI patients.Further analysis revealed that Aβ1-42(r=0.348),T3(r=0.273)and free thyroxin(r=0.214)were positively correlated with disease progression(P<0.05),suggesting that these indicators have the potential to predict disease progression and outcome.Cox regression analysis showed that Aβ1-42 and T3 were important factors of PSCI.Then stratified analysis showed that the lower the Aβ1-42 and T3,the higher risk of PSCI in patients who were aged over 70,female and illiterate.CONCLUSION Aβ1-42 and T3 have the ability to predict the progression of PSCI,which is expected to be applied clinically to reduce the incidence of PSCI and improve the quality of life of patients.

Changes in thyroid function in patients with liver failure and their clinical significance:A clinical study of non-thyroidal illness syndrome in patients with liver failure

Background:Non-thyroidal illness syndrome(NTIS)develops in a large proportion of critically ill patients and is associated with high risk for death.We aimed to investigate the correlation between NTIS and liver failure,and the short-term mortality of patients with these conditions.Methods:The clinical data of 87 patients with liver failure were collected retrospectively,73 of them were randomly selected for an observational study and to establish prognostic models,and 14 for model validation.Another 73 sex-and age-matched patients with mild chronic hepatitis were randomly selected as a control group.Serum free triiodothyronine(FT3),free thyroxine(FT4),and thyroid-stimulating hormone(TSH)were measured.The clinical characteristics of patients with liver failure and NTIS were analyzed.The follow-up of patients lasted for 3 months.Additionally,the values for predicting short-term mortality of model for end-stage liver disease(MELD),Child-Turcotte-Pugh(CTP),chronic liver failure-sequential organ failure assessment(CLIF-SOFA)scores,FT3-MELD model,and FT3 were evaluated.Results:The observation group had significantly lower FT3(2.79±0.71 vs.4.43±0.75 pmol/L,P<0.001)and TSH[0.618(0.186-1.185)vs.1.800(1.570-2.590)mIU/L,P<0.001],and higher FT4(19.51±6.26 vs.14.47±2.19 pmol/L,P<0.001)than the control group.NTIS was diagnosed in 49 of the patients with liver failure(67.12%).In the observation group,patients with NTIS had a higher mortality rate than those without(63.27%vs.25.00%,P=0.002).Across the whole cohort,the 3-month mortality was 50.68%.The international normalized ratios(INR)were 2.40±1.41 in survivors and 3.53±1.81 in deaths(P=0.004),the creatinine(Cr)concentrations were 73.27±36.94μmol/L and 117.08±87.98μmol/L(P=0.008),the FT3 concentrations were 3.13±0.59 pmol/L and 2.47±0.68 pmol/L(P<0.001),the MELD scores were 22.19±6.64 and 29.57±7.99(P<0.001),the CTP scores were 10.67±1.53 and 11.78±1.25(P=0.001),and the CLIF-SOFA scores were 8.42±1.68 and 10.16±2.03(P<0.001),respectively.FT3 was negatively correlated with MELD score(r=−0.430,P<0.001).An FT3-MELD model was established by subjecting FT3 concentration and MELD score to logistic regression analysis using the following formula:Logit(P)=−1.337×FT3+0.114×MELD+0.880.The area under the receiver operating characteristic(ROC)curve was 0.827 and the optimal cut-off value was 0.4523.The corresponding sensitivity and specificity were 67.6%and 91.7%.The areas under the ROC curve for FT3 concentration,MELD score,CTP score,and CLIF-SOFA score were 0.809,0.779,0.699,and 0.737,respectively.Conclusions:Patients with liver failure often develop NTIS.FT3-MELD score perform better than CTP and CLIF-SOFA scores in predicting mortality in patients with liver failure.Thus,the FT3-MELD model could be of great value for the evaluation of the short-term mortality of such patients.

Relationship between Free Thyroxine and Islet Beta-cell Function in Euthyroid Subjects

Thyroid hormones have a specific effect on glucose-induced insulin secretion from the pancreas.We aimed to investigate the association between euthyroid hormones and islet betacell function in general population and non-treated type 2 diabetes mellitus(T2DM)patients.A total of 5089 euthyroid participants(including 4601 general population and 488 non-treated T2DM patients)were identified from a cross-sectional survey on the prevalence of metabolic diseases and risk factors in East China from February 2014 to June 2016.Anthropometric indices,biochemical parameters,and thyroid hormones were measured.Compared with general population,non-treated T2DM patients exhibited higher total thyroxine(TT4)and free thyroxine(FT4)levels but lower ratio of free triiodothyronine(T3):T4(P<0.01).HOMA-βhad prominently negative correlation with FT4 and positive relationship with free T3:T4 in both groups even after adjusting for age,body mass index(BMI)and smoking.When analyzed by quartiles of FT4 or free T3:T4,there were significantly decreased trend of HOMA-β going with the higher FT4 and lower free T3:T4 in both groups.Linear regression analysis showed that FT4 but not FT3 and free T3:T4 was negatively associated with HOMA-β no matter in general population or T2DM patients,which was independent of age,BMI,smoking,hypertension and lipid profiles.FT4 is independently and negatively associated with islet beta-cell function in euthyroid subjects.Thyroid hormone even in reference range could play an important role in the function of pancreatic islets.

Evaluation of Thyroid Hormones Levels in Libyan Patients with Chronic Renal Failure before and after Maintenance Hemodialy

Data from recent studies revealed that kidney diseases might affect the thyroid function in various ways. A variety of alterations in thyroid hormone levels and metabolism have also been reported in patients with chronic renal failure (CRF) in some studied population. In addition, it was reported that serum levels of both T3 and T4 might alter immediately after a hemodialysis (HD) treatment than before. Therefore, this study was aimed to investigate the level of triiodothyronine (T3) and thyroxine (T4) in CRF Libyan patients before and after HD. This study was carried out on 46 CRF patients (30 males and 16 females) with a mean age of 47.46 ± 15.75 years. These patients were treated at the hemodialysis unit of Educational Central Zelitin Hospital, Zelitin, Libya. None of these patients apparently have any thyroid problems and no history of drug intake that may affect thyroid function. Blood samples were taken from each patient to measure serum levels of T3 and T4, before and after HD. In addition, the effects of several variables including age, gender, body mass index (BMI), presence of both hypertension and, diabetes mellitus and duration of kidney dialysis on serum levels of T3 and T4 before and after HD were also studied. After HD, there was a statistically significant increase in the serum levels of T3, T4. The age, gender, BMI, duration of kidney dialysis and the presence of hypertension and diabetes mellitus did not have any significant effect on the serum level of T3 and T4 before and after HD. However, the serum levels of T3 and T4 were still in the normal range in these examined patients either before or after HD. From these findings, it can be concluded that these CRF patients may be in a euthyroid state, because the serum levels of T3 and T4 were in the normal range. In addition, HD was seemed to improve the T3 and T4 thyroid hormone concentrations, suggesting that HD might activate the secretion of thyroid gland and catabolism. The other variables did not play any role in thyroid hormone levels in these patients either before or after HD. It is highly recommended that large scale evaluation of thyroid hormone levels in Libyan CRF patients is performed by more patients, especially elderly patients.

聊城市妊娠妇女甲状腺激素参考区间的建立

目的：建立本实验室妊娠妇女促甲状腺激素（TSH）、游离甲状腺素（FT4）和游离三碘甲状腺原氨酸（FT3）的参考区间。方法：将826例妊娠妇女分为妊娠早中晚期3组，用Beckman access2化学发光分析仪及其配套试剂检测TSH、FT4、FT3，初步建立参考区间。结果：TSH参考区间：妊娠早期0.11～2.88 uIU/ml，妊娠中期0.24～3.31 uIU/ml，妊娠晚期0.55～3.78 uIU/ml。FT4参考区间：妊娠早期0.69～1.13 ng/dl，妊娠中期0.56～0.99 ng/dl，妊娠晚期0.49～0.89 ng/dl。FT3参考区间：妊娠早期2.67～4.03 pg/ml，妊娠中期2.35～3.56 pg/ml，妊娠晚期2.08～3.25 pg/ml。结论：建立了本院妊娠妇女血清TSH、FT4、FT3的参考区间，该区间与Beckman access2化学发光分析仪说明书提供的参考区间有差异。各实验室应根据不同仪器和人群等建立TSH、FT4、FT3的参考区间。

Effect of estradiol-17β on pituitary-thyroidal axis of Japanese eel (Anguilla japonica)

The effect of estradiol-17β (E2)treatment on the pituitary-thyroidal axis has been investi- gated in female Japanese eels in seawater. The eels were injected with 1 mg/kg body weight (BW) weekly for two to eight weeks; another group was treated with 5 mg/kg BW weekly for eight weeks and sacrificed three days after the last injection. In the pituitary, using RT-PCR systern, the thyroid stim- ulating hormone 3 subunit mRNA (TSHβ MRNA) level is slowly increased in the low-dose E2 treatment group. A significant increase in values occurred after eight weeks E2 injections. The histological structure of the thyroid follicles suggests a hypo-activity as shown by a reduced epithelial cell height in eels injected with E2 after six and eight times, and eventually reached a minimum level after eight weeks. Using ra- dioimmunoassay of thyroxine (T4),triiodothyronine (T3) in the serum, a slowly decrease of both hor- mones is demonstrated. On the other hand, the TSHβ mRNA level is significantly increased from initial in the high-dose E2 treatment group. The histological structure of the thyroid follicles suggests a hypo- activity, and a sharp decrease of the both hormones is also indicated. These data suggest that the expres- sion of TSHβ mRNA level is increased and thyroid hormone release is depressed by E2, the effects de- pend upon E2 inection period and dose. Furthermore, E2 could not directly influence the TSHβ mRNA expression and, TSH transcription might be controlled by a negative feedback of thyroid hormone.

The Relationship Among the Reaction Product Colors of Non-specific Esterase by Alpha-naphthyl Acetate Method

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INTRAUTERINE GROWTH RETARDATION AT FULL TERM PREGNANCIES WITH ENDOCRINE FACTORS

Objective To investigate the relationship between intrauterine growth retardation (IUGR) and endocrine parameters so as to assess the effects or the main endocrine ractors on IUGR. The concentrations of growth hormone(GH), insulin, T3, T4 and TSH were measured in umbilical cord blood, amniotic fluid and maternal serum.Methods The samples were collected from 23 pregnant women who were diagnosed as the full term IUGR, 42 normal full term pregnant women with normal infants’ weight were taken as control. Growth hormone and insulin were measured by radioimmunoassay. T3, T4 and TSH were investigated by micro-radioimmunoassay. Results The concentrations of growth hormone, insulin and T4 in umbilical cord blood were lower in IUGR than that in control group(GH4. 63μ/L vs 7. o1μg/L, insulin 1o. 68μIU/ml vs 31. 44μIU/ml, T487. 39nmol/L vs 138. 1onmol/L. P <o. o5, o. o5 and o. o5, respectively). The TSH concentration in umbilical cord blood was higher in IUGR than in control group (1o. 84μmIU/L vs 5. 75μmIU/L, P <o. o1 ). The concentration of growth hormone in maternal serum and the concentration of insulin in amniotic fluid were also lower in IUGR group than in control group(GH 1. 77μg/L vs 2. 74μg/L,P <o. o1, insulin 5. 84μIU/ml vs 15. 64μIU/ml, P <o. o1). Conclusion This study confirms that full term neonates with IUGR are abnormal in endocrine factors. The inadequacy of growth hormone may be one of the causes of IUGR. The relatlve scarcity of growth hormone and insulin seems to be a factor to compromise the fetus’ metabolism. Besides, the early hypothyrosis of infants with IUGR might protect them from unfavorable environment in the uterine.

The Reproductive and Thyroid Hormonal Profile of Khat (Catha Edulis) Chewers

The effects of khat on the hormonal levels have been established;however, the effects on human beings are controversial. The aim of our study was to investigate the possible effects of khat on the levels of serum thyroid hormones, testosterone, estradiol (E2), prolactin and cortisol in men. A total of 50 blood samples were collected from healthy males who referred to chew khat for more than 10 years and analyzed for the above hormones. The results were compared to the hormonal levels of 35 non khat chewers. Chewing khat causes significant increases in the testosterone (P < 0.03), prolactin (P < 0.05), E2 (P < 0.00005), FT3 (P < 0.04), and TSH (P < 0.05) levels. No significant differences were found in the serum level of FT4 between the two groups. The level of cortisol were significantly lower (P < 0.001) in the khat chewers group compared to the control group. This study suggests that khat chewing can cause reduction in the cortisol level, which may cause increases of testosterone, prolactin and E2. In addition, chewing khat increases the level of TSH and FT3 serum levels. Therefore, khat may contribute to the relevant disorders caused by abnormal levels of the studied hormones in the people who are chewing

Effect of Pressurized Soy Protein Isolate upon the Growth and Antioxidants Functions of SD Rat

The objective of this study is to specify the effect of pressurized soy protein isolate (pSPI), upon the physical development, growth hormones and antioxidants functions of SD rats. The methodology depends on the selection of one hundred male SD rats, divided randomly into 5 groups. Each group consists of 20 rats. The groups will be defined as one blank control group, three groups with pSPI at low, medium and high doses and another control group with native soy protein isolates (nSPI). Low, medium and high doses are represented by 0.333 g/kg, 1.667 g/kg and 3.333 g/kg pSPI per weight, respectively. The native soy protein isolate is represented by 3.333 g/kg nSPI per weight. In every group, four animals will be taken out to collect the blood samples and analyze insulin like growth factor-I, growth hormone, thyroid stimulating hormone, thyroxine and triiodothyronin. The other SD rats will be subjected to feeding for 63 consecutive days. The body weight, the body length and food intake of each rat are measured. The total antioxidant capacity, superoxide dismutase (SOD), malondialdehyde and Glutathione Peroxidase in liver and serum of each rat will be analyzed. The results indicated that the groups with medium and high dose of pSPI result in an obvious increase in the body weight, body length and food utilization rate of SD rats. Also, pSPI has a great effect on the growth and antioxidants functions of SD rat.

Cardiovascular mechanisms of thyroid hormones and heart failure:Current knowledge and perspectives

A multiple hormonal imbalance that accompanies heart failure(HF)may have a significant impact on the clinical course in such patients.The non-thyroidal illness syndrome(NTIS),also referred to as euthyroid sick syndrome or low triiodothyronine syndrome,can be found in about 30%of patients with HF.NTIS represents a systemic adaptation to chronic illness that is associated with increased cardiac and overall mortality in patients with HF.While conclusions on thyroid-stimulating hormone,free triiodothyronine,total and free thyroxine are currently unresolved,serum total triiodothyronine levels and the ratio of free triiodothyronine to free thyroxine seem to provide the best correlates to the echocardiographic,laboratory and clinical parameters of disease severity.HF patients with either hyper-or hypothyroidism should be treated according to the appropriate guidelines,but the therapeutic approach to NTIS,with or without HF,is still a matter of debate.Possible treatment options include better individual titration of levothyroxine therapy,combined triiodothyronine plus thyroxine therapy and natural measures to increase triiodothyronine.Future research should further examine the cellular and tissue mechanisms of NTIS as well as new therapeutic avenues in patients with HF.

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

Background:Changes in thyroid hormone levels are commonly recognized characters among the elderly,which were reported to potentially influence incident frailty.Therefore,we examined the cross-sectional associations of thyroid hormones(THs)with frailty as well as the five components characterizing frailty(fatigue,resistance,ambulation,number ofillnesses,and loss of weight)among the oldest-old.Methods:Four hundred and eighty-seven community-dwelling oldest-old from a local community in Haidian District,Beijing,participated in our recruitment campaign between April 2019 and May 2020.The primary outcomes were a definitive diagnosis of frailty according to the FRAIL scale(Fatigue,Resistance,Ambulation,Illnesses,Loss of weight)and a positive score for each frailty subdomain.Demographic information(age,sex,marital status,and educational status),comorbidities,and details on the participants lifestyles were recorded.Serum THs including free triodothyronin(fT3),triiodothyronine(T3),free thyroxine(fT4),and thyroxine(T4)and thyroid stimulating hormone(TSH)levels were also measured at the beginning of our study.Logistic regressions were conducted to screen for potential risk factors for frailty and its subdomains.Results:Among the total 487 subjects at enrollment,60(12.23%)of them were diagnosed with subclinical hypothyroidism and 110(22.59%)of the total population scored positive for frailty.Logistic regression analyses adjusted for all potential confounders,showed that frailty was significantly associated with the serum TSH concentration(odds ratio[OR]:1.06),fT3 concentration(OR:0.54),and subclinical hypothyroidism score(OR:2.18).The association between fT4 and frailty was absent in our observational study.The fT3/fT4 ratio characterizing peripheral hormone conversion was also tested to be correlated with frailty.Conclusion:Subclinical hypothyroidism,higher TSH level,lower fT3 level,and decreased fT3/fT4 ratio were all associated with frailty assessed by the FRAIL scale among the community-dwelling oldest-old,suggesting a relevant role of thyroid function in aging.Future longitudinal studies are warranted to determine the casual relationship between thyroid dysfunction and frailty in the oldest-old.