Thyroid dysfunction prevalence and relation to glycemic control in patients with type 2 diabetes mellitus

ObjectiveIt is usually difficult to clinically identify thyroid abnormalities in diabetics as features of thyroid dysfunction may simulate diabetes symptoms or complications. So, assessing thyroid dysfunction prevalence in patients with type 2 diabetes mellitus (DM) would help better control of DM and its complications. Several studies reported this prevalence, however, some included small sample size or lacked a control group. We aimed to determine thyroid dysfunction prevalence in diabetic patients as well as its relation to glycemic control.MethodsA cross-sectional study included 200 patients having type 2 DM and 200 apparently healthy controls. Each participant was tested for fasting and 2-h post-prandial blood glucose, glycated haemoglobin (HbA1C), thyroid function tests: thyroid-stimulating hormone (TSH), free tri-iodothyronine (FT3), free thyroxine (FT4), serum total cholesterol and triglycerides and thyroid antibodies; anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) for hypothyroidism only.ResultsThere was a significant increase in serum TSH and T3 levels in diabetics when compared with the controls, (P < 0.001, P = 0.001), respectively. Thyroid dysfunction was significantly more prevalent in patients with HbA1c ≥ 8%, (P = 0.0001), and in those having longer diabetes duration, (P < 0.001).ConclusionThere was a higher prevalence of thyroid dysfunction among patients with type 2 DM. This dysfunction increased with the rise of HbA1c. This could suggest that poor glycemic control may have a role in the development of thyroid dysfunction in type 2 DM patients. Subclinical hypothyroidism was the most prevalent type of thyroid dysfunction in diabetic patients.     

Anti-TPO antibodies and screening of thyroid dysfunction in type 1 diabetic patients

The diagnosis of thyroid dysfunction is often late in type 1 diabetic population. So, the aims of this study were 1) to evaluate the prevalences of thyroperoxydase (TPO) and thyroglobulin (Tg) autoantibodies detected by highly sensitive radioimmunological method in a cohort of 258 adult type 1 diabetic patients without evidence of clinical thyroid disease; 2) to determine whether or not measurement of TPO and/or Tg antibodies can identify subjects at risk of clinical or infraclinical thyroid dysfunction by measuring TSH in the entire group. TPO antibodies were found in 45 of the 258 diabetic patients (17%). The prevalence of TPO antibodies was not influenced by the following factors: gender, duration of disease, age at screening and at diabetes diagnosis, positivity of familial history. Tg antibodies were found in 19 patients (7%), including 13 cases with TPO antibodies. All patients without TPO antibody (n=213), including Tg-positive patients displayed TSH values in normal range. Among the 45 TPO-positive patients, 11 patients displayed infraclinical thyroid dysfunction. At the end of the 5-year follow-up, only 2/45 patients became anti-TPO negative. Thirteen of the 45 patients developed subclinical or clinical thyroid diseases (4 Graves'disease and 9 thyroiditis with hypothyroidism). By contrast, none of 45 TPO negative patients, sex and age matched with the TPO-positive patients, developed during follow-up anti-TPO positivity and/or infraclinical thyroid dysfunction. In conclusion, the determination of TPO antibodies by a highly sensitive method allows identifying diabetic patients with thyroid autoimmunity and at risk of subsequent impaired thyroid function, whatever age at diagnosis and diabetes duration. By contrast, anti-Tg determination did not give further information about subsequent thyroid dysfunction. In TPO antibody positive patients repeated thyroid clinical examination and TSH determination could be recommended to detect infraclinical thyroid dysfunction.     

Evaluation of thyroid structure and function in patients with Turner syndromes

The aim of our study was an estimation of thyroid structure and function in 37 patients with Turner syndrome aged from 19 to 60 years and in control group of healthy women. In each case the following studies were performed: cytogenetic examination, thyroid ultrasonography, serum total and free thyroid hormones, TSH, thyroglobulin (Tg), thyroid hormones binding globulin (TBG), antithyroglobulin and antithyroperoxidase antibodies (anti-Tg and anti-TPO) levels. In Turner syndrome ultrasonographic volume of the thyroid was significantly lower than in control group (11.03 vs 16.98 cm3). Abnormalities of thyroid function were found in 8 (22%) studied cases (subclinical primary hypothyroidism in 16%, full-clinical primary hypothyroidism in 3% and hyperthyroidism in course of Graves disease in 3%). Serum elevated antithyroid antibodies were present in 62% cases of Turner syndrome and were significantly higher than in control group (16%). In Turner syndrome thyroid diseases are more frequent than in healthy population. Every patient with Turner syndrome needs routine diagnostics of the thyroid structure and function.     

Thyroid disorders in Brazilian patients with celiac disease

INTRODUCTION/AIM: Patients with celiac disease (CD) can develop a gluten related autoimmune disorder that affects not only the small intestine but other tissues as well. An increased prevalence of autoimmune diseases has been reported, particularly autoimmune thyroiditis. The aim of this study was to characterize thyroid disorders in patients with CD. PATIENTS/METHODS: Fifty-two patients with CD (43 female, 9 male; mean age, 41.1 years) were studied. Nine were on a gluten-free diet (GFD). They were divided into four groups: Group 1, without thyroid involvement (n=30); Groups 2A-C, with thyroid involvement (n=22); Group 2A, subclinical hypothyroidism (n=11); Group 2B, clinical hypothyroidism (n=10); and Group 2C, other thyroid disorders (n=1). CD was confirmed by serologic and histologic criteria. Thyroid involvement was detected by measurement of thyroid stimulating hormone (TSH) and anti-thyroperoxidase antibodies (anti-TPO). RESULTS: Increased levels of TSH and/or anti-TPO levels were detected in Groups 2A (21.1%) and 2B (19.2%). The patients of Group 2B presented clinical symptoms of hypothyroidism before the diagnosis of CD, and 5 of these patients were receiving levothyroxine. One woman (Group 2C; 1.92%) had a medullary carcinoma. There was statistical significance between the age when thyroid disease was diagnosed (current age) and the age of CD diagnosis between Groups 1 and 2B. Patients with thyroid involvement presented associated diseases such as diabetes mellitus (2), Down's syndrome (2), ulcerative colitis (1), and dermatitis herpetiformis (2). CONCLUSIONS: Our findings demonstrated an increased prevalence of thyroid disorders (hypothyroidism, 19.2%; and subclinical hypothyroidism, 21.2%), and other associated diseases in celiac patients, even on a GFD, increasing with the age of the patients. Screening for associated diseases is recommended for patients with CD, independent of age at diagnosis or treatment duration.     

Subclinical hypothyroidism is an independent risk factor for atherosclerosis and myocardial infarction in elderly women: the Rotterdam Study

BACKGROUND: Overt hypothyroidism has been found to be associated with cardiovascular disease. Whether subclinical hypothyroidism and thyroid autoimmunity are also risk factors for cardiovascular disease is controversial. OBJECTIVE: To investigate whether subclinical hypothyroidism and thyroid autoimmunity are associated with aortic atherosclerosis and myocardial infarction in postmenopausal women. DESIGN: Population-based cross-sectional study. SETTING: A district of Rotterdam, The Netherlands. PARTICIPANTS: Random sample of 1149 women (mean age +/- SD, 69.0 +/- 7.5 years) participating in the Rotterdam Study. MEASUREMENTS: Data on thyroid status, aortic atherosclerosis, and history of myocardial infarction were obtained at baseline. Subclinical hypothyroidism was defined as an elevated thyroid-stimulating hormone level (>4.0 mU/L) and a normal serum free thyroxine level (11 to 25 pmol/L [0.9 to 1.9 ng/dL]). In tests for antibodies to thyroid peroxidase, a serum level greater than 10 IU/mL was considered a positive result. RESULTS: Subclinical hypothyroidism was present in 10.8% of participants and was associated with a greater age-adjusted prevalence of aortic atherosclerosis (odds ratio, 1.7 [95% CI, 1.1 to 2.6]) and myocardial infarction (odds ratio, 2.3 [CI, 1.3 to 4.0]). Additional adjustment for body mass index, total and high-density lipoprotein cholesterol level, blood pressure, and smoking status, as well as exclusion of women who took beta-blockers, did not affect these estimates. Associations were slightly stronger in women who had subclinical hypothyroidism and antibodies to thyroid peroxidase (odds ratio for aortic atherosclerosis, 1.9 [CI, 1.1 to 3.6]; odds ratio for myocardial infarction, 3.1 [CI, 1.5 to 6.3]). No association was found between thyroid autoimmunity itself and cardiovascular disease. The population attributable risk percentage for subclinical hypothyroidism associated with myocardial infarction was within the range of that for known major risk factors for cardiovascular disease. CONCLUSION: Subclinical hypothyroidism is a strong indicator of risk for atherosclerosis and myocardial infarction in elderly women.     

Circulating lipids and minor abnormalities of thyroid function

OBJECTIVE: We determined the effect of subclinical hyperthyroidism (defined as low circulating TSH with normal serum free T4) and subclinical hypothyroidism (raised serum TSH with normal free T4) on fasting levels of blood lipids. DESIGN: Prospective study of lipid concentrations in patients identified as having abnormal TSH. PATIENTS: Patients were identified in a population screening study of those over 60 years, with persistently low TSH with normal free T4 (n = 27) or high TSH but normal free T4 (n = 57). Patients were matched to controls with normal serum TSH by age, sex and body mass index. MEASUREMENTS: Serum TSH, free T4, free T3, total cholesterol, low density lipoprotein (LDL) cholesterol and high density lipoprotein (HDL) cholesterol. RESULTS: Serum free T4 measurements were significantly higher in those with subclinical hyperthyroidism than in their controls (P < 0.001) and lower in those with subclinical hypothyroidism than in matched controls (P < 0.001). Measurement of fasting lipids in patients and controls revealed a marked (12.2%) reduction in serum total cholesterol in subclinical hyperthyroidism (P < 0.01); no significant difference in fasting lipids between patients with subclinical hypothyroidism and controls was observed. CONCLUSIONS: Differences in free T4 between those with low or high TSH and controls with normal TSH suggest that abnormalities of TSH directly reflect thyroid hormone excess and deficiency. A reduction in cholesterol in those with subclinical hyperthyroidism suggests a direct influence of thyroid hormone excess on lipid metabolism in these patients.     

Well-being, health-related quality of life and cardiovascular disease risk profile in women with subclinical thyroid disease - a community-based study

OBJECTIVES: The aim of this study was to evaluate whether subclinical thyroid disease is associated with impaired health-related quality of life and a more adverse cardiovascular disease risk profile. DESIGN: A community-based cross-sectional study. SETTING AND PARTICIPANTS: A total of 1423 non-healthcare-seeking women, aged 18-75 years were randomly recruited from the community via the electoral roll from April 2002 to August 2003. MAIN OUTCOME MEASURES: These were the scores for the Short-Form 36 (SF-36), the Psychological General Well-being Index (PGWI), thyroid hormone levels, serum lipids and high sensitivity C-reactive protein (hsCRP). Subclinical hypothyroidism (SCH) and subclinical hyperthyroidism (SCHyper) were defined as serum TSH > 4.0 mIU/l and < 0.5 mIU/l, respectively, with a normal free thyroxine (free T4) level. RESULTS: Evaluable data were available for all participants. 10.7% of all women had an abnormal TSH value. The prevalence of a low TSH level by age group ranged from 1.2% to 6.4%, whereas the prevalence of an elevated TSH level ranged from 2.8% to 9.2% and increased with age (P = 0.002). There were no significant differences between women with SCH or SCHyper and age-matched controls for the total PGWI score or the Mental and Physical Component Scores of the SF-36. Women with SCH were no different from controls for serum lipids or hsCRP. Using linear regression, SCH vs. euthyroidism did not make an independent contribution to variation in either total cholesterol or triglycerides, with or without adjustment for age +/- age(2) +/- BMI. CONCLUSIONS: Our data indicate that subclinical thyroid disease in women in the community is not associated with lower well-being or impaired health-related quality of life and SCH is not associated with increased serum markers of CVD risk.     

开展亚临床甲状腺功能减退症的临床研究

亚临床甲状腺功能减退症 (甲减 )是一种常见的内分泌专业亚临床疾病 ,主要诊断依据是血清TSH水平增高 ,而血清FT4正常。亚临床甲减的主要不良后果是发展为临床甲减和促进缺血性心脏病的发生。影响亚临床甲减发展为临床甲减的主要因素有两个 :血清TSH水平和甲状腺自身抗体 ,两个因素有叠加作用。甲状腺激素替代治疗对于阻止亚临床甲减发展为临床甲减的效果尚不确切 ;亚临床甲减与高胆固醇血症、高血压、吸烟和糖尿病一样 ,构成动脉粥样硬化和心肌梗塞的独立危险因素 ,其对此两病的危险度分别为 1.9和 3 .1。甲状腺素纠正亚临床甲减对降低血清胆固醇有一定效果 ;妊娠妇女的亚临床甲减对后代的智力影响已经引起高度关注。我国一组根据对流行病学调查的结果 ,提出了血清TSH、甲状腺自身抗体 (TPOAb、TgAb)的正常值范围 ,以及与疾病相关的甲状腺自身抗体的切割点值 ,可供参考。     

The prevalence of subclinical hypothyroidism at different total plasma cholesterol levels in middle aged men and women: a need for case-finding?

OBJECTIVE: In order to determine whether screening of thyroid function is justified in patients with hypercholesterolaemia, we determined the prevalence of subclinical hypothyroidism at different levels of total plasma cholesterol in middle-aged men and women. DESIGN AND METHODS: 1200 participants were selected from a population based cross sectional study on risk factors for cardiovascular diseases. The participants were divided into three groups: total plasma cholesterol < 5 mmol/l, total plasma cholesterol 5-8 mmol/l, total plasma cholesterol > 8 mmol/l. Each group was comparable in size and sex distribution. Subclinical hypothyroidism was defined as plasma TSH levels higher than 4 mU/l, in the presence of normal free thyroxine (FT4(4)) concentration. RESULTS: Plasma samples of a total of 1191 participants were analyzed. The overall prevalence of subclinical hypothyroidism was 1.9% in men and 7.6% in women of middle age. In women the prevalence of subclinical hypothyroidism increased from 4.0 percent in the lowest, to 10.3 percent in the highest cholesterol stratum (P = 0.02). In men, the mean prevalence was 1.8 percent and roughly similar in the various strata. After age correction, an increase of 1 mU/l TSH in women was associated with an increase of 0.09 mmol/l total plasma cholesterol (95% confidence interval (CI) 0.02-0.16 mmol/l). A similar trend was found in men (0.16 mmol/l, 95% CI -0.02-0.34 mmol/l). CONCLUSIONS: In the population, the prevalence of subclinical hypothyroidism is up to 10 percent in middle aged women with high levels of total plasma cholesterol and may justify case-finding. In these women approximately 0.5 mmol/l of total plasma cholesterol can be attributed to the subclinical thyroid dysfunction. In men a similar correlation between thyroid dysfunction and total plasma cholesterol is seen, but the prevalence of thyroid dysfunction is considerably lower.     

Spontaneous subclinical hypothyroidism in patients older than 55 years: an analysis of natural course and risk factors for the development of overt thyroid failure

We aimed to analyze the natural course of subclinical hypothyroidism, quantify the incidence rate of overt hypothyroidism, and evaluate the risk factors for the development of definitive thyroid failure in elderly patients. One hundred seven patients (93 women and 14 men) over age 55 yr with subclinical hypothyroidism and no previous history of thyroid disease were prospectively studied. Subjects were followed up for 6-72 months (mean, 31.7 months) with repeated determinations of TSH and free T(4). Twenty-eight patients (26.8%) developed overt hypothyroidism, and 40 (37.4%) showed normalization of their TSH values. The incidence rate of overt hypothyroidism was 9.91 cases per 100 patient-years in the whole population, and 1.76, 19.67, and 73.47 cases per 100 patient-years in subjects with initial TSH values between 5.0-9.9, 10.0-14.9, and 15.0-19.9 mU/liter, respectively. Kaplan-Meier analysis showed that the development of definitive thyroid hypofunction was significantly related to the presence of symptoms of hypothyroidism, goiter, positive thyroid antibodies (P < 0.05), and mainly low normal free T(4) (P < 0.01) and high TSH (P < 0.0001) concentrations at baseline. A stepwise multivariate Cox regression analysis showed that the only significant factor for progression to overt hypothyroidism was serum TSH concentration (P < 0.0001). In conclusion, TSH concentration is the most powerful predictor for the outcome of spontaneous subclinical hypothyroidism in patients over age 55 yr. Subjects with mildly elevated TSH have a low incidence rate of overt hypothyroidism. We recommend follow-up with clinical and biochemical monitoring in these patients.     

Decreased HDL cholesterol in subclinical hypothyroidism: the effect of L-thyroxine therapy

Thyroid function and lipid tests were measured in 29 premenopausal women with subclinical hypothyroidism. This group was compared with 41 euthyroid women matched for age and metabolic parameters. In basal condition there was no difference in thyroid hormone levels between the two groups except for TSH concentration (P less than 0.01). Total cholesterol, triglycerides and apolipoprotein (apo A1, A2, B) of women with subclinical hypothyroidism were not different from controls. HDL cholesterol was significantly decreased in subclinical hypothyroidism compared to the controls (P less than 0.01). With thyroxine therapy, normalization of serum TSH was associated with (1) no significant change in total cholesterol and triglycerides, (2) an increase of HDL cholesterol (P less than 0.01) and apoprotein A1 (P less than 0.05) levels. Total cholesterol/HDL cholesterol ratio was increased in subclinical hypothyroidism (P less than 0.01). During L-thyroxine therapy this ratio returned to normal value. Decreased HDL cholesterol concentration might cause coronary heart disease reported in women with subclinical hypothyroidism.     

亚临床甲状腺功能减退症

亚临床甲状腺功能减退症（甲减）是一种亚临床甲状腺疾病。诊断标准是血清促甲状腺激素（TSH）水平高于正常上限而游离T4水平尚在正常范围。目前全世界亚临床甲减的平均患病率为4％-10％,主要发生在女性和老年人群。桥本甲状腺炎是最常见的病因。其主要的临床危害包括引起血脂异常、导致动脉粥样硬化和冠心病、影响认知功能,还可导致不孕和流产。治疗主要针对血清TSH〉10ml U／L的患者,应用左旋-T4替代治疗。对于血清TSH4～10ml U／L,特别是甲状腺自身抗体阳性者需密切监测。此外,对妊娠期亚临床甲减患者的治疗要求控制TSH〈2．5ml U／L。     

Thyroid and celiac disease: clinical, serological, and echographic study

Objective: We sought to reevaluate the prevalence of thyroid dysfunction and thyroid autoimmunity in 47 patients with celiac disease; 91 healthy subjects were studied as controls. Both patients and controls were from Sardinia, Italy.
Methods: Diagnosis of celiac disease was made on the basis of clinical history, presence of positive antigliadin IgA (AGA-A) and IgG (AGA-G) antibodies, antireticulin antibodies (ARA), antiendomysium antibodies (EMA), and was confirmed by jejunal biopsy. HLA class II typing for DQB1 and DQA1 alleles was performed in 36/47 celiac patients. Thyroid was evaluated by palpation and echography; serum free thyroid hormones (FT4, FT3), thyrotropic hormone (TSH), and antithyroid peroxidase autoantibodies (anti-TPO) were assayed by radioimmunoassays.
Results: The prevalence of anti-TPO was higher in celiac patients (29.7%) than in healthy controls (9.6%) (   p < 0.001  ) and thyroid echography frequently displayed (42.5%) a hypoechogenic pattern. Five anti-TPO–positive celiac patients were hypothyroid (two overt, three subclinical). A higher but not significantly different prevalence of anti-TPO (3/ 7 = 42.8%) was found in celiac patients displaying the DQB1*0502 genotype, when compared with the remaining patients (8/29 = 27.6%).
Conclusions: An elevated prevalence of clinical and subclinical autoimmune thyroid autoimmunity was found in Sardinian celiac patients, especially in those displaying the DQB1*0502 genotype; this finding could be related to a particular genetic background of the Sardinian population.     

The spectrum of thyroid disorders in systemic lupus erythematosus

To study the spectrum of thyroid disorders in systemic lupus erythematosus (SLE). Hundred SLE patients as per American Rheumatology Association(ARA) classification criteria underwent clinical examination, including assessment of disease activity (SLEDAI) and laboratory evaluation for serum triiodothyronine (T3),free thyroxine (FT4), thyroid stimulating hormone (TSH), antithyroperoxidase (TPO) antibody and antithyroglobulin (TG) antibody. Hundred age- and sex-matched apparently healthy individuals served as control. Thirty-six (36%) lupus patients had thyroid dysfunction when compared to 8 (8%) of controls and all of them were women. Primary hypothyroidism was the commonest dysfunction in 14 (14%), while subclinical hypothyroidism and subclinical hyperthyroidism was seen in 12 (12%) and 2 (2%), respectively. Eight (8%) had isolated low T3 consistent with sick euthyroid syndrome. Eighteen (50%) of thyroid dysfunction were autoimmune in nature (autoantibody positive) and rest 18 (50%) were non-autoimmune. Euthyroid state with the elevation of antibodies alone was seen in 12 (12%) of the lupus patients. In contrast, only 5 (5%) of controls had primary hypothyroidism and 3 (3%) had subclinical hypothyroidism, while none had hyperthyroidism. SLEDAI score and disease duration were compared between lupus patients with thyroid dysfunction to those with normal thyroid function. A statistically significant association was found between SLEDAI and thyroid dysfunction of sick euthyroid type.SLE disease duration had no statistically significant association with thyroid dysfunction. Prevalence of thyroid autoantibodies in lupus patients was 30% when compared to 10% of controls. Ninety-six (96%) of the SLE patients were ANA positive, while 4 (4%) of them were ANA negative but were anti-Sm antibody positive. There were no suggestions of any other autoimmune endocrine diseases like diabetes or Addison’s disease (clinically and on baseline investigations) in our lupus cohort and hence no further work up was done for these diseases. Thyroid disorders are frequent in SLE and are multifactorial with a definite higher prevalence of hypothyroidism as well as thyroid autoantibodies.     

Risk for ischemic heart disease and all-cause mortality in subclinical hypothyroidism

We investigated possible associations between subclinical hypothyroidism and atherosclerotic diseases (ischemic heart disease and cerebrovascular disease) and mortality. Of 2856 participants (mean age 58.5 yr) in a thyroid disease screening between 1984 and 1987, 257 subjects with subclinical hypothyroidism (TSH > 5.0 mU/liter) and 2293 control subjects (TSH range 0.6-5.0 mU/liter) were analyzed. In the baseline cross-sectional analysis, subclinical hypothyroidism was associated with ischemic heart disease independent of age, systolic blood pressure, body mass index, cholesterol, smoking, erythrocyte sedimentation rate, or presence of diabetes mellitus [odds ratio (OR), 2.5; 95% confidence interval (95% CI), 1.1-5.4 in total subjects and OR, 4.0; 95% CI, 1.4-11.5 in men] but not in women. However, there was no association with cerebrovascular disease (OR, 0.9; 95% CI, 0.4-2.4). We were unable to detect an influence of thyroid antibody presence on the association between subclinical hypothyroidism and ischemic heart disease. In a 10-yr follow-up study until 1998, increased mortalities from all causes in yr 3-6 after baseline measurement were apparent in men with subclinical hypothyroidism (hazard ratio, 1.9-2.1) but not in women, although specific causes of death were not determined. Our results indicate that subclinical hypothyroidism is associated with ischemic heart disease and might affect all-cause mortality in men.     

Predictivity of thyroid autoantibodies for the development of thyroid disorders in children and adolescents with Type 1 diabetes.

AIMS: To investigate the prevalence of thyroid autoantibodies and their significance for the development of thyroid disorders in children and adolescents with Type 1 diabetes. METHODS: Antibodies to thyroglobulin (anti-TG) and thyroperoxidase (anti-TPO) were measured in 216 patients (113 boys; median age 12.9 years (range 1-22 years)) with Type 1 diabetes (diabetes duration 2.5 years (0-14 years)) in a cross-sectional study. Sixteen patients with significantly elevated anti-TPO titres were followed longitudinally (6.0 years (4-13 years)) including the measurement of anti-TPO, anti-TG, T(3), T(4), thyroid-stimulating hormone (TSH) and ultrasound assessment. RESULTS: Twenty-two patients (10.0%) had significantly elevated titres of anti-TPO, 19 (8.7%) of anti-TG and 13 (5.9%) of both autoantibodies. Girls had more frequently elevated anti-TPO antibodies than boys (P < 0.05). Eight of 16 patients (50%) developed thyroid disorders defined by a TSH elevation (> or = 4.5 microU/ml) and/or sonographic thyroid abnormalities during a median time of 3.5 years (2-6 years) after first detection of anti-TPO positivity. They were characterized by higher levels of anti-TPO (P = 0.001) and a more frequent coexistence of anti-TG antibodies (P = 0.002) than those with no development of thyroid disorder even after an observation period of 5.5 years (5-10 years). CONCLUSIONS: Because 50% of children with diabetes and significant titres of anti-TPO develop thyroid problems within 3-4 years, examinations of thyroid antibodies should be performed yearly. In cases of significant antibody titres, thyroid function tests and ultrasound assessment are recommended in order to minimize the risk of undiagnosed hypothyroidism in these patients.     

Increased prevalence of thyroid autoimmunity in patients successfully treated for Cushing's disease

BACKGROUND: Cushing's disease is characterized by abnormalities of immune function. OBJECTIVE: To evaluate the prevalence of autoimmune thyroid diseases in patients with Cushing's disease (CD), after successful treatment and the possible association between previous nodular goitre or positive thyroid autoantibodies during the active phase of CD and the subsequent development of autoimmune thyroid diseases after cure. SUBJECTS AND METHODS: Twenty patients with CD and 40 sex- and age-matched healthy controls were considered for the study. In CD patients, thyroid ultrasonography and measurement of circulating free thyroxine (fT4), free triiodothyronine (fT3), thyroid stimulating hormone (TSH), antithyroglobulin (anti-Tg) and antithyroperoxidase (anti-TPO) antibodies were performed at diagnosis and 6 months after disease cure while in controls they were performed only at study entry. RESULTS: Serum fT3, and fT4 levels were similar in patients, either during the active phase or after cure of the disease, and controls. Conversely, in the patients, serum TSH levels were significantly lower during active disease (0. 4 +/- 0.05 mU/l, P = 0.001) and significantly higher after disease cure (4.7 +/- 0.1 mU/l, P < 0.001) than in controls (2.3 +/- 0.4 mU/l). Four patients (20%) and 11 controls (27.5%) had positive anti-Tg and/or anti-TPO titre at study entry, while eight patients (40%) developed positive anti-Tg and/or anti-TPO titre after disease cure. The prevalence of positive antithyroid antibodies titre in cured CD patients was significantly higher than that observed in the same patients during the active disease (P = 0.008) and in controls (P = 0.031). A significantly higher prevalence of autoimmune thyroiditis was found in patients cured from CD (35%) than in patients with active CD (0%) (P = 0.016) and in controls (10%) (P = 0.031). A significant association was found between the presence of autoimmune thyroiditis after CD cure and the presence of a previous nodular goitre (P = 0.017) or positive thyroid autoantibodies titre (P = 0.007) during the active phase of the disease. CONCLUSION: Patients successfully treated for Cushing's disease have an increased prevalence of thyroid autoimmunity and autoimmune thyroiditis as compared to a control population. Therefore, patients with hypercortisolism need an accurate evaluation of thyroid function after remission of the disease in order to prevent the eventual onset of subclinical or overt post-thyroiditis hypothyroidism.     

Five‐year incidence and progression of thyroid dysfunction in an older population

Background: Very few studies have assessed both the incidence and progression of thyroid dysfunction in a single older population‐based cohort. In this study, we aimed to assess the 5‐year incidence, progression and risk factors for development of thyroid dysfunction in an older Australian population. Methods: The Blue Mountains Eye Study is a longitudinal population‐based cohort study. During 1997–1999, 1768 participants (≥55 years) had thyroid function assessed. After excluding participants reporting any form of treatment for their thyroid condition at baseline, 951 participants (91.4%) without thyroid dysfunction and 54 (5.4%) with thyroid dysfunction were re‐examined 5 years later. Thyroid dysfunction was defined using serum thyrotropin (thyroid stimulating hormone (TSH)) screen, followed by serum free T4 assessment. Results: The overall 5‐year incidence of thyroid dysfunction was 4.7% (95% confidence interval (CI) 3.4–6.1). Obesity (body mass index ≥ 30 kg/m²) and serum TSH > 2 mIU/L at baseline predicted incident overt hypothyroidism (odds ratio (OR) 4.05, CI 1.74–9.41) and (OR 5.46, CI 1.16–25.67) respectively. The 5‐year incidence of subclinical hypothyroidism was significantly higher in women than in men, 2.5% versus 0.7% (P= 0.03). Progression to overt hypothyroidism was observed in 17.9% of subjects with subclinical hypothyroidism over 5 years. Conclusions: The 5‐year incidence of thyroid dysfunction in this older population was relatively low, and was associated with obesity and serum TSH level > 2 mIU/L at baseline. Over one in six persons with subclinical hypothyroidism progressed to overt thyroid dysfunction over the 5‐year period. Our findings highlight the need for appropriate management of subclinical hypothyroidism among older people.     

Thyroid disorders during interferon alpha therapy in 625 patients with chronic hepatitis C: a prospective cohort study

AIM: to report the prevalence, risk factors, management and long-term outcome of thyroid disorders caused by INFalpha in patients with chronic hepatitis C. PATIENTS AND METHODS: From January 1991 to December 2004, 625 patients with chronic hepatitis C underwent INFalpha therapy. TSH assay was normal and antithyroperoxidase antibodies (anti-TPO) was performed before onset antiviral treatment; then TSH was performed every 2 months in all patients during therapy, and every 3 months after treatment. RESULTS: 58 patients developed thyroid disorder (8.9%). Mean age was 50.6+/-13 years; sex ratio: 1 M/2 F; the anti-TPO antibodies were positive before onset antiviral treatment in 9 patients (13.8%). 26 patients developed hypothyroidism (44.8%), 9 patients developed hyperthyroidism (15.5%) and among them 3 cases of Grave's disease. Biphasic thyroiditis occurred in 21 patients (36.2%), anti-TPO increase during treatment in 2 patients (3.5%) without hypothyroidism. The dysthyroidism was more frequent in risk in female gender (p<0.05) and in the group with positive antiTPO antibodies before treatment (p<0.02). CONCLUSION: Female gender and positive antiTPO antibodies are the predictive factors of development of the thyroid dysfunction during INFalpha therapy.     

亚临床甲状腺功能减退症

亚临床甲状腺功能减退症(甲减)是一种业临床甲状腺疾病.诊断标准是血清促甲状腺激素(TSH)水平高于正常上限而游离T4水平尚在正常范围.目前全世界业临床甲减的平均患病率为4%～10%,主要发生在女性和老年人群.桥本甲状腺炎是最常见的病因.其卡要的临床危害包括引起血脂异常、导致动脉粥样硬化和,冠心病、影响认知功能,还可导致不孕和流产.治疗主要针对血清TSH10 mIU/L的患者,应用左旋-T4替代治疗.对于血清TSH 4～10 mIU/L,特别是甲状腺自身抗体阳性者需密切监测.此外,对妊娠期亚临床甲减患者的治疗要求控制TSH<2.5 mlU/L.