Prevalence of thyroid dysfunction in Thai HIV-infected patients

Increasing prevalence of thyroid function abnormality has been reported in HIV-infected patients. We aim to evaluate the prevalence and assess risk factors of thyroid dysfunction in Thai HIV-infected patients. A cross-sectional study was conducted. Serum thyroid hormone concentrations (FT4, FT3, and TSH) and thyroid autoantibodies (TgAb and TPOAb) were measured by electrochemiluminescence immunoassay. A total of 200 HIV-infected outpatients were included. Ninety-seven patients (48.5%) were men (mean age of 36.3 +/- 8.3 years). Duration of HIV infection was 49.6 +/- 35.1 months and 53% had previous opportunistic infections (OI). Mean CD4 cell count was 340.6 +/- 173.1 cells/mm(3). Of these, 167 patients (83.5%) received antiretroviral therapy (ARV). Abnormal thyroid function test was detected in 32 patients (16%). Twenty-seven patients (13.5%) had decreased thyroid function (primary hypothyroidism 3, subclinical hypothyroidism 12, and low FT4 with low or normal TSH 12) whereas 5 patients had increased thyroid function (overt hyperthyroidism 1, subclinical hyperthyroidism 1, and isolated high FT3 3). None had clinical features of thyroid hormone dysfunction. Thirteen patients (6.5%) had thyroid antibody positive. Patients who received ARV had higher mean FT3 levels than those who were na?ve to ARV (p = 0.017). History of previous OI was found to be an independently significant risk factor for decreased thyroid function with the odds ratio of 3.28 (95% CI =1.183-9.099; p = 0.022). Hypothyroidism was common among Thai HIV-infected patients, especially in those who had history of previous OI. It is therefore suggested that screening and/or monitoring of thyroid hormone in HIV-infected patients should be considered.     

Thyroid Function Abnormalities and Cognitive Impairment in Elderly People: Results of the Invecchiare in Chianti Study

OBJECTIVES: To investigate thyroid function testing abnormalities in older persons and to explore the relationship between thyroid dysfunction and cognition.
DESIGN: Cross-sectional.
SETTING: Community-based.
PARTICIPANTS: One thousand one hundred seventy-one men and women aged 23 to 102.
MEASUREMENTS: Thyroid function was evaluated by measuring plasma concentrations of thyrotropin (TSH), free thyroxine (FT4), and free triiodothyronine (FT3). Cognition was evaluated using the Mini-Mental State Examination (MMSE). Prevalence of overt and subclinical thyroid dysfunction was evaluated in different age groups (<65 vs ≥65). Age trends in TSH, FT4, and FT3 were examined in euthyroid participants. The cross-sectional association between thyroid dysfunction and MMSE score was evaluated adjusting for confounders.
RESULTS: Subclinical hypothyroidism and subclinical hyperthyroidism were more prevalent in older than in younger participants (subclinical hypothyroidism, 3.5% vs 0.4%, P <.03; subclinical hyperthyroidism, 7.8% vs 1.9%, P <.002). In euthyroid participants, TSH and FT3 declined with age, whereas FT4 increased. Older participants with subclinical hyperthyroidism had lower MMSE scores than euthyroid subjects (22.61±6.88 vs 24.72±4.52, P <.03). In adjusted analyses, participants with subclinical hyperthyroidism were significantly more likely to have cognitive dysfunction (hazard rate=2.26, P =.003).
CONCLUSION: Subtle age-related changes in FT3, FT4, and TSH occur in individuals who remain euthyroid. Subclinical hyperthyroidism is the most prevalent thyroid dysfunction in Italian older persons and is associated with cognitive impairment.     

妊娠早期甲状腺功能筛查策略的有效性分析

目的 获得妊娠早期甲状腺功能异常的患病率,进行妊娠早期甲状腺功能筛查策略的有效性分析.方法调查中国沈阳2 899名妊娠早期妇女(4～12周).通过问卷调查方法收集所有孕妇的背景资料,将孕妇分为高风险组与非高风险组.应用妊娠早期特异性甲状腺功能正常参考范围,获得妊娠早期甲状腺功能异常患病率.结果高风险组甲状腺功能减退症患病率明显高于非高风险组(16.3%对5.3%,RR=3.1,95%CI 2.4～4.0,P＜0.01).甲状腺过氧化物酶抗体(TPOAb)阳性(RR=4.7,95%CI3.6～6.0,P＜0.01),甲状腺疾病个人史(RR=3.2,95%CI 1.9～5.4,P＜0.01)均可显著增加甲状腺疾病患病的风险.高风险组甲状腺功能亢进症的患病率明显高于非高风险组(3.1%对1.4%,RR=2.2,95%CI 1.2～3.9,P=0.006).TPOAb阳性(RR=2.6,95%CI 1.3～5.0,P=0.007),甲状腺疾病个人史(RR=4.7,95%CI 1.7～12.5,P=0.006)均可显著增加甲状腺功能亢进发生的风险.高风险组与非高风险组间相比低T4血症患病率差异无统计学意义(0.9%对0.9%,x2=0.008,P=0.928).仅在高危孕妇中筛查甲状腺功能会漏掉56.7%甲状腺功能减退症(临床和亚临床)患者及64.7%甲状腺功能亢进症(临床和亚临床)患者.结论推荐对妊娠早期所有孕妇进行甲状腺功能的筛查.筛查指标应当包括TSH、FT4和TPOAb.     

Assessment of thyroid function in two hundred patients with beta-thalassemia major.

Despite improved hematologic care, multiendocrine dysfunction is a common complication of homozygous transfusion-dependent beta-thalassemia. In this study our goal was to estimate the prevalence of thyroid dysfunction in a large homogenous group of thalassemic patients. Two hundred patients with beta-thalassemia major (100 males and 100 females; mean age, 23.2 +/- 6.7 years; age range 11-43 years), regularly transfused and desferioxamine chelated, were randomly selected from a pool of approximately 800 patients with beta-thalassemia followed in our department. Thyroid function and iron-load status were evaluated by measurements of free thyroxine (FT4), free triiodothyronine (FT3), thyrotropin (TSH), and serum ferritin levels. Of the subgroup of patients who proved to have normal thyroid hormone values, 26 (12 males, 14 females; mean age, 23.6 +/- 6.8 years; age range, 15-36 years) were randomly selected and underwent a standard TRH stimulation test. Thyroid dysfunction was defined as follows: overt hypothyroidism: low FT4 and/or FT3, increased TSH levels; subclinical hypothyroidism: normal FT4, FT3, increased TSH levels; exaggerated TSH response: normal FT4, FT3, normal basal TSH, deltaTSH > or = 21 microIU/mL (TSH levels measured prior and 30 minutes after intravenous TRH administration). Normal thyroid hormone values were found in 167 (83.5%) of the 200 patients studied. Eight (4%) of the remaining patients had overt hypothyroidisim, and 25 (12.5%) had subclinical hypothyroidism. Exaggerated TSH response to TRH was revealed in 7 of the 26 patients with normal hormone values tested (26.9%). Antithyroglobulin and anti-thyroid peroxidase (TPO) antibody titers were negative in 191 patients (95.5%). Mean ferritin levels in hypothyroid and euthyroid patients were 2707.66 +/- 1990.5 mg/L and 2902.9 +/- 1997.3 mg/L, respectively, (p = 0.61), indicating no correlation between ferritin levels and thyroid functional status. Mean ferritin levels in the patients who responded normally to TRH stimulation and in those who overresponded, were 2,586 +/- 1791 mg/L and 3,228 +/- 2473 mg/L, respectively (p = 0.46; NS). Thyroid failure is a rather rare endocrine complication in patients with beta-thalassemic from Greece. In our series, no case of central hypothyroidism was observed. No correlation was found between thyroid functional status and ferritin plasma levels. Approximately 1 of 5 beta-thalassemic patients with normal thyroid hormone values showed an exaggerated TSH response to TRH test. It is to be investigated how many of these patients will establish overt or subclinical hypothyroidism in the future.     

Socio demographic wise risk assessment of thyroid function abnormalities in far western region of Nepal: A hospital based descriptive study

Objective

To know the status of thyroid disorder in population of far western region of Nepal.

Methods

A total of 808 cases (133 men and 675 non pregnant women) were included and study was carried out using data retrieved from the register maintained in the Department of Biochemistry of the Nepalgunj Teaching Hospital between 1st January, 2011 and 28th February, 2012. The variables collected were age, sex, and thyroid function profile including free T3, free T4 and TSH.

Results

The percentage of thyroid disorders was 33.66% in far western region of Nepal. The people were highly affected by overt hyperthyroidism (14.9%) followed by subclinical hyperthyroidism (9.9%). The subclinical hypothyroidism was 7.9% while 1% overt hypothyroidism only in a far western region of Nepal. Females were highly affected by overt hyperthyroidism (17.8%), followed by subclinical hyperthyroidism (11.9%). A total of 5.9% females were affected by subclinical hypothyroidism while only 1.2% by overt hypothyroidism. Males were affected only by subclinical hypothyroidism (18.0%) in this present study. High number of total thyroid dysfunction was observed in 21 to 40 years of age groups, followed by 41 to 60 years of age groups. Less than 40 years people were having 1.03, 0.99, 2.51 and 1.15 times risk of developing overt hyperthyroidism, subclinical hyperthyroidism, overt hypothyroidism and subclinical hyperthyroidism respectively compared to greater than 40. Female were having 0.29 times risk of developing subclinical hyperthyroidism compared to male. But overt hyperthyroidism, subclinical hyperthyroidism and overt hypothyroidism female were having more risk of developing compared to male.

Conclusions

The thyroid disorder, especially overt hyperthyroidism (14.9%) and subclinical hyperthyroidism (9.9%) was high. Further studies are required to characterize the reasons for this high prevalence.     

The prevalence of undiagnosed thyroid disorders in a previously iodine-deficient area.

OBJECTIVE: The aim of the present study was to analyze the current status of morphologic and functional thyroid abnormalities in a previously iodine-deficient area. METHODS: The population based Study of Health in Pomerania (SHIP) comprised 4310 participants, aged 20-79 years. Thyroid function (thyrotropin [TSH] free triiodothyronine [FT(3)], and free thyroxine [FT(4)]) and serum autoantibodies to thyroperoxidase (TPOAb) were evaluated from blood samples. Thyroid structure and size were measured by ultrasound. Data from 3941 participants with no known thyroid disorders were analyzed. RESULTS: The median iodine urine excretion was 12.4 microg/dL. The rate of decreased serum TSH levels (<0.3 mIU/L) was 11.3%; 2.2% of participants had suppressed serum TSH levels (<0.1 mIU/L). The prevalence of subclinical hyperthyroidism was 1.8%, the prevalence of overt hyperthyroidism 0.4%. Elevated TSH levels were found in 1.2% of individuals. Subclinical hypothyroidism was observed in 0.5%, overt hypothyroidism in 0.7% of the sample. Elevated TPOAb were detected in 7% of subjects, 4.1% of participants had TPOAb greater than 200 IU/mL. The prevalence of goiter was 35.9%. An inhomogeneous echo pattern was detected in 35.2% and nodules in 20.2% of participants. Diffuse autoimmune thyroiditis was diagnosed in 47 subjects (1.2%). CONCLUSION: There are a number of thyroid disorders in this previously iodine-deficient region. Further studies are required to investigate the change of thyroid disorders during iodine supplementation programs.     

A sensitive thyroid stimulating hormone assay for screening of thyroid functional disorder in elderly Japanese

The use of a screening test for thyroid functional disorder by sensitive thyroid stimulating hormone assay in the elderly was investigated. The basal thyroid stimulating hormone levels predicted the response of thyroid stimulating hormone to thyrotropin releasing hormone; it was suppressed in 99 (99.0%) of 100 hyperthyroid patients. Therefore, not only primary hypothyroidism but also hyperthyroidism can be excluded when the serum thyroid stimulating hormone levels are normal. An epidemiological study was then performed on 2,421 (76.7%) of the Japanese general population aged 40 or over recruited from the residents in Hisayama town and also in 122 residents between 20 and 40 years of age. Additional free T4 measurement was necessary in about 10% of the residents with abnormal TSH levels to confirm the diagnosis of hyperthyroidism or distinguish latent from overt hypothyroidism. There was a significant correlation between age and serum thyroid stimulating hormone levels after logarithmic conversion (r = 0.1533, P less than .001). The prevalence of thyroid dysfunction found in 1,026 males and in 1,395 females aged 40 or over was, respectively: hyperthyroidism, less than 0.1% and 0.2%, latent (subclinical) hypothyroidism, 3.2% and 5.5%, and overt hypothyroidism, 0.4% and 0.7%. We conclude that the screening with this sensitive thyroid stimulating hormone assay and additional free T4 measurement is useful for detection of patients with thyroid functional disorder.     

No association between HIV disease and its treatment and thyroid function

OBJECTIVES: The aims of the study were (i) to investigate the prevalence of overt and subclinical thyroid disease in HIV-positive patients in a London teaching hospital; (ii) to determine risk factors associated with the development of thyroid dysfunction, including highly active antiretroviral therapy (HAART) and individual antivirals, and (iii) to determine the occurrence of thyroid dysfunction longitudinally over 3 years. METHODS: The study consisted of retrospective analyses of thyroid function tests (TFT) in HIV-positive patients. The period prevalence of and factors associated with clinical and subclinical thyroid dysfunction were investigated. Patients with normal TFT but previous thyroid disease were identified from pharmacy records and included in the overt category. RESULTS: A total of 1565 patients (73% of the clinic population) had at least one TFT taken since 2001. Overall, 3584 samples were analysed. Of the patients included in the study, 1233 (79%) were male, 1043 (66%) were white and 365 (23%) were black African, and in 969 (62%) the main risk for HIV was homosexual sex. Median age at baseline was 37 years. Nine hundred patients (58%) were on HAART at the start of the study. Thirty-nine (2.5%) were found to have overt hypothyroidism, and eight (<1%) had overt hyperthyroidism. Sixty-one (4%) had subclinical hypothyroidism, five (<1%) had subclinical hyperthyroidism and 263 (17%) had a nonthyroidal illness. A normal TFT was obtained for 1118 patients (75.5%). Multivariate analysis suggested that no independent variables were significantly associated with overt hypothyroidism, including HAART and stavudine use specifically. Repeated measurements over 3 years were available for 825 patients and only eight new cases (1%) of overt thyroid disease occurred. CONCLUSIONS: The prevalence of overt thyroid disease was low in this cohort, suggesting that screening is not warranted.     

Alterations in thyroid function tests in aged hospitalized patients: prevalence, aetiology and clinical outcome

Background Thyroid dysfunction is common in aged people and has recently been associated to mortality. Aims Our aims have been (1) to assess the prevalence of alterations in thyroid function tests in hospitalized patients over age 60 years and (2) to study the relationship between thyroid functional status and mortality during hospitalization. Methods We studied a group of 447 patients (62% women), aged 61–101 year, hospitalized during 2005. Thyroid dysfunction was assessed by measuring serum concentrations of thyrotrophin (TSH), free thyroxine (FT4), and free thriiodothyronine (FT3). Thyroid autoimmune status was evaluated through thyroid peroxidase (TPO) and thyroglobulin (TG) antibodies quantification. Results Twenty‐one patients (4·7%, 19 women) showed previously known thyroid dysfunction. 332 patients (74·3%) showed alterations in thyroid function tests. Euthyroid sick syndrome (ESS) was the derangement more frequently found (n = 278, 62·2%). After excluding ESS patients, 60 patients (13·4%) showed thyroid dysfunction: overt hypothyroidism, 14 (3·1%); subclinical hypothyroidism, 25 (5·6%); overt hyperthyroidism, 11 (2·5%), and subclinical hyperthyroidism, 10 patients (2·2%). Thyroid autoimmunity was positive in only 4·0% and 2·3% of patients, for TPOAb and TgAb, respectively. The presence of alterations in thyroid function tests was positively associated with the age of the patients and mortality during hospital stay (P < 0·001). Serum levels of FT3 were negatively related to death during hospitalization (OR 0·56; CI 95%, 0·38–0·81; P < 0·01). Conclusions About three quarters of patients admitted in our geriatric unit exhibited alterations in thyroid function tests. This finding was associated with elevated age and poor prognosis. The reduction of FT3 values was a powerful predictor for mortality during hospitalization in elderly patients.     

碘致甲状腺功能减退症的流行病学对比研究

目的：研究不同碘摄入量人群的临床甲减和亚临床甲减患病率,方法：选择盘山,彰武和黄骅3个农村社区（分别为低碘,适碘和高碘地区（）,在入户问卷调查的基础上行采样调查,共问卷调查16287人,采样3761人,所有采样对象接受体格检查,,测定血清TSH,甲状腺过氧化的酶抗体（TPOAb),甲状腺球蛋白抗体（TGAb)和甲状腺球蛋白（TG）,测定尿碘浓度及进行甲状腺B超检查,TSH异常者测定FT4,FT3和TSH受体抗体（TRAb)。结果：盘山,彰武和黄骅社区成人尿碘水平分别为103．1ug/L,374.8ug/L和614.6ug/L,盘山,彰武和黄骅社区临床甲减患病率分别为0．27％,0．95％和2．05％, 临临床甲减的患病率分别为0．91％,2．90％,和5．96％,引起临床甲减的主要原因是自身免疫性甲状腺炎,亚临床甲减中三分之一患者甲状腺自身抗体阳性,结论：横断面的流行病学对比研究证实碘摄入量增加有可能导致甲状腺功能减退症患病率增加。     

Evaluation of thyroid functions with respect to iodine status and TRH test in chronic autoimmune thyroiditis

Objective: Chronic autoimmune thyroiditis (CAT) is the most common form of thyroiditis in childhood and a frequent cause of acquired hypothyroidism. The objective of this study was to evaluate the thyroid status of childrenand adolescents with CAT with respect to iodine status and diagnostic values of thyrotropin-releasing hormone (TRH) test. Methods: Seventy-one children (mean age: 11.6 years) were studied in a retrospective analysis. Free thyroxine (T4), thyrotropin (TSH), TSH response to TRH test, thyroid autoantibodies, thyroid sonography, and urinary iodine excretion (UIE) were evaluated. Results: At diagnosis, 8.5% of patients had overt hypothyroidisim and 36.6% subclinical hypothyroidism; 5.6% had overt hyperthyroidisim and 8.5% had subclinical hyperthyroidism. Of them, 40.8% were euthyroid. Median UIE was 51 mg/L in overt hypothyroidism and 84 mg/L in subclinical hypothyroidism. The values were 316 mg/L and 221 mg/L in overt and subclinical hyperthyroidism, respectively. Basal TSH showed a strong correlation with peak TSH level on TRH test. Thirty-four percent of patients with normal basal TSH level showed an exaggerated TSH response. Conclusion: Iodine deficiency was seen more in cases with hypothyroidism, while excess of iodine was observed to be more frequent in hyperthyroid patients. Iodine status was a strong predictorof the thyroid status in CAT. TRH test may be helpful in further delineating patients with subclinical hypothyroidism. Conflict of interest:None declared.     

Lower prevalence of mild hyperthyroidism related to a higher iodine intake in the population: prospective study of a mandatory iodization programme

Objective  Marked differences in pattern of thyroid dysfunction are seen in populations with different iodine intakes. We evaluated the influence of a higher iodine intake on thyroid hormone levels and the prevalence of thyroid dysfunction in the Danish population.
Design  Two cross-sectional studies matched on a group level according to sex and age.
Participants  In all, 8219 individuals were examined before ( n  = 4649) or after ( n  = 3570) the introduction of a mandatory iodization programme in 2000 in two regions with established mild and moderate iodine deficiency. Serum TSH, fT₄ and fT₃ were measured. An ultrasonography of the thyroid was performed.
Results  We found a higher median serum TSH after the introduction of mandatory iodization of salt: 1·51 mU/l (10–90th percentiles: 0·72–3·00) vs. 1·30 mU/l (10–90th percentiles: 0·59–2·66) before iodization. The difference was found in both regions and across age groups. There was a lower prevalence of mild hyperthyroidism and a tendency towards a lower prevalence of overt hyperthyroidism. The prevalence of mild hypothyroidism increased, most pronounced among young women after iodization. Conversely, there was a lower prevalence of undiagnosed overt hypothyroidism. However, when currently treated participants were included, the prevalence of hypothyroidism increased after iodization in the area with formerly mild iodine deficiency.
Conclusion  A change in pattern of thyroid dysfunction was seen in relation to mandatory iodization of salt. There was no rise in the prevalence of hyperthyroidism and the prevalence of mild hyperthyroidism was halved. Conversely, prevalence of hypothyroidism increased.     

Prevalence of subclinical thyroid dysfunction and its relation to socioeconomic deprivation in the elderly: a community-based cross-sectional survey

CONTEXT: Population-based screening has been advocated for subclinical thyroid dysfunction in the elderly because the disorder is perceived to be common, and health benefits may be accrued by detection and treatment. OBJECTIVE: The objective of the study was to determine the prevalence of subclinical thyroid dysfunction and unidentified overt thyroid dysfunction in an elderly population. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional survey of a community sample of participants aged 65 yr and older registered with 20 family practices in the United Kingdom. EXCLUSIONS: Exclusions included current therapy for thyroid disease, thyroid surgery, or treatment within 12 months. OUTCOME MEASURE: Tests of thyroid function (TSH concentration and free T4 concentration in all, with measurement of free T3 in those with low TSH) were conducted. EXPLANATORY VARIABLES: These included all current medical diagnoses and drug therapies, age, gender, and socioeconomic deprivation (Index of Multiple Deprivation, 2004). ANALYSIS: Standardized prevalence rates were analyzed. Logistic regression modeling was used to determine factors associated with the presence of subclinical thyroid dysfunction. RESULTS: A total of 5960 attended for screening. Using biochemical definitions, 94.2% [95% confidence interval (CI) 93.8-94.6%] were euthyroid. Unidentified overt hyper- and hypothyroidism were uncommon (0.3, 0.4%, respectively). Subclinical hyperthyroidism and hypothyroidism were identified with similar frequency (2.1%, 95% CI 1.8-2.3%; 2.9%, 95% CI 2.6-3.1%, respectively). Subclinical thyroid dysfunction was more common in females (P < 0.001) and with increasing age (P < 0.001). After allowing for comorbidities, concurrent drug therapies, age, and gender, an association between subclinical hyperthyroidism and a composite measure of socioeconomic deprivation remained. CONCLUSIONS: Undiagnosed overt thyroid dysfunction is uncommon. The prevalence of subclinical thyroid dysfunction is 5%. We have, for the first time, identified an independent association between the prevalence of subclinical thyroid dysfunction and deprivation that cannot be explained solely by the greater burden of chronic disease and/or consequent drug therapies in the deprived population.     

249名老年人中甲状腺疾病的发生及转归临床分析

目的研究老年人甲状腺疾病的患病率和发生发展特点。方法249例来自我国辽宁省、河北省的老年人(男102名,女147名;年龄60~88岁)参加了1999年的横断面调查,5年后进行了随访。初访和随访时均测定血清促甲状腺激素(TSH)、甲状腺过氧化物酶抗体(TPOAb)和甲状腺球蛋白抗体(TgAb),TSH异常者加测游离甲状腺激素(FT3、FT4)。结果该研究人群TSH正常范围为0.28~4.75mU/L。甲状腺功能异常(含临床和亚临床型)的总患病率10.84%,TPOAb和TgAb的阳性率分别为12.85%和11.65%。初访时确定为正常甲状腺功能的老年人(n=222,随访率79.7%),5年后新发临床甲状腺功能亢进(甲亢)1例、亚临床甲亢2例(均为男性),亚临床甲减3例(均为女性)。初访时甲状腺自身抗体阴性者,随访时有6例出现抗体的阳转,但未伴有甲状腺功能的异常。结论老年人甲状腺疾病患病率较高,应当开展甲状腺疾病筛查;老年人的亚临床甲状腺疾病多数可自行缓解,可采取以观察为主的处理方式。     

Thyroid function in humans with morbid obesity.

Morbidly obese subjects may present with abnormal thyroid function tests but the reported data are scarce. Therefore, we studied the thyroid parameters in 144 morbidly obese patients, 110 females and 34 males, to assess the prevalence of hypothyroidism. Eleven percent (11.8%) carried the diagnosis of hypothyroidism and were undergoing levothyroxine (LT4) replacement therapy, 7.7% had newly diagnosed subclinical hypothyroidism, 0.7% had subclinical hyperthyroidism and 7.7% were euthyroid with positive antibodies (anti-thyroid peroxidase antibodies [TPOAb]). From the 144 subjects, we selected a cohort of 78 euthyroid subjects with negative TPOAb, who did not receive LT4 replacement or suppression therapy (the experimental group) and compared them to 77 normal-weight euthyroid subjects, TPOA-negative, matched for age and gender who served as controls. The experimental group had higher serum levels of triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), and thyrotropin (TSH) compared to the control group. Serum TSH concentration was associated with fasting serum insulin levels and insulin resistance but not with serum leptin levels, body mass index (BMI), fat mass, and lean body mass. In conclusion, in morbidly obese individuals, the prevalence of overt and subclinical hypothyroidism was high (19.5%). The morbidly obese subjects have higher levels of T3, FT3, T4, and TSH, probably the result of the reset of their central thyrostat at higher level.     

Autoimmune thyroid disease in pregnancy and the postpartum period: relationship to spontaneous abortion.

The aim of this study was to determine the prevalence of autoimmune thyroid disease and the risk of miscarriage in autoimmune thyroid antibody (ATA)-positive women. Eight hundred seventy-six subjects completed the study, and 12.3% were thyroid antibody-positive (4.5% tested positive for both thyroid peroxidase antibody [TPO-Ab] and thyroglobulin autoantibody [Tg-Ab], 4.79% were TPO-Ab-positive only, and 3.1% were Tg-Ab-positive only). Fifty percent of the ATA-positive women and 14.1% of the ATA-negative group had a history of spontaneous abortion. Forty-eight of the ATA-positive women developed postpartum autoimmune thyroid dysfunction (PATD). Of these, 50% had hypothyroidism alone, 31.3% had transient hyperthyroidism followed by hypothyroidism, and 18.8% had transient thyrotoxicosis alone. Of the 48 PATD subjects, 12.5% developed persistent hypothyroidism. None of the ATA-negative women developed any form of thyroid dysfunction. The thyroid-stimulating hormone (TSH) levels in the ATA-positive group were significantly higher than those in the ATA-negative group, and only the ATA-positive women with a history of abortion had significantly higher TSH and lower free thyroxine (FT4) concentrations than the other subgroups. The results revealed a 5.5% prevalence rate for PATD in the study population. In addition to TPO-Ab, Tg-Ab is a useful marker for autoimmune thyroiditis.     

The immunofluorometric TSH assay as first-line test for suspected thyroid dysfunction

In this study of 103 patients with suspected thyroid dysfunction, the diagnostic value of a single basal immunofluorometric (IFMA) TSH measurement was evaluated and compared with the classical TRH test with RIA-TSH measurements, plasma TT4 concentrations and FT4I. A single basal TSH determination accurately predicted the TRH-stimulated TSH response, making the TRH test redundant in most patients. Because undetectable basal TSH did not always exclude a small rise in TSH, the TRH test could still be indicated in patients receiving thyroxine suppression therapy for thyroid cancer. Basal TSH differentiated accurately between euthyroidism and thyroid dysfunction, especially at the decision values of 0.20 and 4.0 mU/l, as proposed in this study. For diagnosis of clinical and subclinical hypo- and hyperthyroidism, additional measurement of TT4 and/or FT4I is necessary. A 2-yr follow-up of patients with subclinical thyroid dysfunction did not show progression to clinical disease. In some of the patients with subclinical hypothyroidism, substitution therapy with thyroxine had been started after initial testing. Indications for treatment of subclinical thyroid dysfunction are discussed.     

Follow up of thyroid hormone parameters in chronically ill geriatric patients: screening for thyroid disorders at hospital admission justified.

The objective of this study was to investigate if screening of chronically ill geriatric patients for thyroid dysfunction is justified just upon hospital admission. TSH was measured in 124 patients at hospital admission and 11-86 (Median 37) days afterwards. FT4 was measured in cases with subnormal, suppressed or elevated TSH (43 cases). Out of 81 patients with normal (0.5-3.6 mU/l) TSH, the control value was subnormal (0.1-<0.5 mU/l) in 6 and elevated (>3.6 mU/l) in one case, but in none of the patients became suppressed (<0.1 mU/l). In 13/30 patients with subnormal TSH the control value was normal but in none of the patients suppressed or elevated. On the contrary, all cases with suppressed (N=9) or elevated (N=4) TSH remained in the same ranges at follow up. Low (<13 pmol/l, N=3) or elevated (>27 pmol/l, N=5) initial FT4 levels did not change in the follow up as well. Out of 35 patients with normal FT4, one became low and another elevated. Improvement or worsening of the clinical state in the follow up did not correlate to changes of TSH. The prevalence of unsuspected thyroid dysfunctions were 11.3% (hyperthyroidism clinical: 4, subclinical: 5, hypothyroidism clinical: 3, subclinical: 2 cases). All cases except one with subclinical hypothyroidism were detected by the initial screening. Only one patient with clinical hyperthyroidism was initial misinterpreted as having subclinical disease. Conclusions: In chronically ill geriatric patients investigated at hospital admission, a measurable TSH practically excludes hyperthyroidism in the follow up. Suppressed TSH levels remain suppressed but subnormal levels should be controlled because their normalization frequently occur in the follow up. Screening upon hospital admission is sensitive enough to detect cases of thyroid dysfunction and justified by their high prevalence.     

Prevalence of thyroid dysfunction in elderly subjects. A randomized study in a Norwegian rural community (Naer?y)

The prevalence of thyroid dysfunction was investigated in a small, rural community located at the coast in Middle Norway. Two hundred persons (114 women and 86 men) of the total 802 persons over 70 years of age in the community were examined regarding thyroid dysfunction. Blood samples were drawn from 197 (113 women and 84 men). In women previously diagnosed hypothyroidism was found in 3.5% and previously diagnosed hyperthyroidism in 0.9%. In men no previously diagnosed thyroid disease was found. Undiagnosed primary hypothyroidism (TT4 less than 70 nmol/l and TSH greater than 6 mU/l) was found in 1.8% and 1.2% of women and men, respectively. Latent hypothyroidism (TT4 70-150 nmol/l and TSH greater than 6 mU/l) was found in 3.5% and 2.4%, and borderline hypothyroidism (TSH 4.5-6.0 mU/l) in 3.5% and 2.4%, respectively. Undiagnosed hyperthyroidism was not found in women but in 1.2% of men. Antibody to the thyroid microsomal antigen (TMA) greater than or equal to 400 was detected in 17.5% of women and 9.6% of men. Clearly elevated serum thyrotropin (TSH) concentrations or previously diagnosed thyroid disease were found in 21.7% and 37.5% of the TMA positive women and men, respectively.     

Masked thyroid dysfunction among elderly patients with atrial fibrillation

Seventy-five elderly patients with atrial fibrillation (41 males and 34 females with a mean age of 75.6 years) were studied to evaluate the incidence of masked thyroid dysfunction. A thyrotropin (TSH)-releasing-hormone (TRH) test (intravenous injection of 250 micrograms of synthetic TRH) was performed in the patients and 30 age matched controls without atrial fibrillation. In the controls, no abnormal TRH stimulated TSH response was observed. In the patients with atrial fibrillation, no response of TSH to TRH (hyperthyroidism) was found in 5 cases (6.6%), while hyperresponse of TSH to TRH (hypothyroidism) was found in 6 cases (8.0%). Thyroid dysfunction (hyper or hypothyroidism) was more frequently observed in the patients than in the controls (p less than 0.05). Two of 5 hyperthyroid patients had normal thyroid hormone levels. All patients with hyperthyroidism were treated with antithyroid drugs or 131I. Unfortunately, atrial fibrillation persisted in all but 1 case. It is concluded that the TRH test is a useful screening test for detecting those patients with abnormal thyroid function among elderly patients with atrial fibrillation, and that hypothyroidism should be considered as a cause of atrial fibrillation in the elderly.