Untreated Hypothyroid Patients Research Articles

Synaptic Plasticity and Cognitive Ability in Experimental Adult-Onset Hypothyroidism.

Adult-onset hypothyroidism impairs normal brain function. Research on animal models of hypothyroidism has revealed critical information on how deficiency of thyroid hormones impacts the electrophysiological and molecular functions of the brain, which leads to the well known cognitive impairment in untreated hypothyroid patients. Currently, such information can only be obtained from experiments on animal models of hypothyroidism. This review summarizes important research findings that pertain to understanding the clinical cognitive consequences of hypothyroidism, which will provide a better guiding path for therapy of hypothyroidism. SIGNIFICANCE STATEMENT: Cognitive impairment occurs during adult-onset hypothyroidism in both humans and animal models. Findings from animal studies validate clinical findings showing impaired long-term potentiation, decreased CaMKII, and increased calcineurin. Such findings can only be gleaned from animal experiments to show how hypothyroidism produces clinical symptoms.

Assessment of cardiovascular autonomic dysfunction in untreated adult hypothyroid patients

Introduction and Aim: Hypothyroidism is an endocrine disorder with a high prevalence worldwide in the adult population. Due to the thyroid hormone’s widespread role in controlling metabolic processes to permissive action on the heart, patients with hypothyroidism suffer from a significant chance of acquiring cardiac autonomic dysfunction which further deteriorates the prognosis. Heart rate Variation analysis can be a possible way to detect this autonomic dysfunction early and may help in patient care. This study aims to assess Heart Rate Variability (HRV) parameters in untreated overt hypothyroid patients and compare the parameters of heart rate variability test with an age and sex-matched healthy control group. Materials and Methods: With the permission from the institutional ethics committee, 50 untreated hypothyroid patients are collected from the endocrine outpatient department and 50 healthy age, sex, and matched individuals are taken, maintaining proper inclusion and exclusion criteria. HRV analysis data is collected in both time and frequency domains in both groups and compared using statistical tools. Results: In our research, it is seen that compared to healthy control group, untreated hypothyroid patients have a significant alteration in the following parameters - SDNN (p<0.005) and RMSSD (p<0.009) in the time domain and LF (nu), LF (%), HF (%), LF/HF, HF (nu)[p<0.05] in the frequency domain. Conclusion: Due to several alterations in HRV parameters indicating sympathovagal disbalance in the hypothyroid patients, it can be concluded that untreated hypothyroid patients are prone to develop cardiovascular autonomic dysfunction and HRV analysis can be a possible way to detect it early.

Prevalence of diabetes in people with thyroid dysfunction

ObjectiveTo describe the prevalence and relative risk of diabetes in the population with hypothyroidism and hyperthyroidism. MethodsA retrospective study was carried out using the Primary Care Clinical Database (BDCAP) of the Ministry of Health. Relative risks (OR) and their 95% confidence intervals (CI) were calculated for type 1 (T1D) and type 2 (T2D) diabetes. ResultsIn the group of 2,596,041 hypothyroid patients, we found an OR of 1.77 (1.75−1.80) for T1D, and 1.77 (1.76−1.78) for T2D. This elevated risk was observed in both men and women. Hypothyroid people over 65 years of age had a near neutral risk of T1D (0.96 [0.94−0.99]) and T2D (0.99 [0.98−0.99]). Hypothyroid patients receiving replacement therapy showed a higher risk of T1D (1.32 [1.28−1.36]) and T2D (1.23 [1.22−1.24]) compared to untreated hypothyroid patients. In the group of 418,772 people with hyperthyroidism, an increased risk of T1D (1.66 [1.60−1.72]) and T2D (1.71 [1.70−1.73]) was also noticed. This risk was observed in both sexes. Those over 65 years of age did not present a high risk of T1D (0.89 [0.83−0.95]) and their risk of T2D was close to neutrality (1.03 [1.02−1.05]). Hyperthyroid patients treated with antithyroid agents had a higher risk of T1D (1.26 [1.14−1.40]) and T2D (1.32 [1.28−1.36]) than those without therapy. ConclusionPeople registered in BDCAP of both sexes, under 65 years of age, with thyroid dysfunction have an increased risk of suffering from diabetes, especially those on thyroid medication.

Prevalencia de diabetes en personas con disfunción tiroidea

ObjectiveTo describe the prevalence and relative risk of diabetes in the population with hypothyroidism and hyperthyroidism. MethodsA retrospective study was carried out using the Primary Care Clinical Database (BDCAP) of the Ministry of Health. Relative risks (OR) and their 95% confidence intervals (CI) were calculated for type1 (T1D) and type2 (T2D) diabetes. ResultsIn the group of 2,596,041 hypothyroid patients, we found an OR of 1.77 (95%CI: 1.75-1.80) for T1D, and 1.77 (95%CI: 1.76-1.78) for T2D. This elevated risk was observed in both men and women. Hypothyroid people over 65years of age had a near neutral risk of T1D (0.96 [95%CI: 0.94-0.99]) and T2D (0.99 [95%CI: 0.98-0.99]). Hypothyroid patients receiving replacement therapy showed a higher risk of T1D (1.32 [95%CI: 1.28-1.36]) and T2D (1.23 [95%CI: 1.22-1.24]) compared to untreated hypothyroid patients. In the group of 418,772 people with hyperthyroidism, an increased risk of T1D (1.66 [95%CI: 1.60-1.72]) and T2D (1.71 [95%CI: 1.70-1.73]) was also noticed. This risk was observed in both sexes. Those over 65years of age did not present a high risk of T1D (0.89 [95%CI: 0.83-0.95]) and their risk of T2D was close to neutrality (1.03 [95%CI: 1.02-1.05]). Hyperthyroid patients treated with antithyroid agents had a higher risk of T1D (1.26 [95%CI: 1.14-1.40]) and T2D (1.32 [95%CI: 1.28-1.36]) than those without therapy. ConclusionPeople registered in BDCAP of both sexes, under 65years of age, with thyroid dysfunction have an increased risk of suffering from diabetes, especially those on thyroid medication.

Effects of Slow-Acting Metformin Treatment on the Hormonal and Morphological Thyroid Profile in Patients with Insulin Resistance.

Metformin appears to reduce TSH levels in untreated hypothyroid patients. In contrast, in euthyroid patients with type 2 diabetes mellitus (T2DM), metformin is initially devoid of effects on TSH. However, it is followed by a significant reduction in TSH level after twelve months of treatment. Additionally, some evidence suggests that metformin may also improve thyroid morphological abnormalities. This study aimed to evaluate the effects of metformin not only on TSH and thyroid hormone values, but also on thyroid volume and nodules. A total of 50 patients (mean age: 36.9 ± 12.8 years) with insulin resistance (homeostatic model assessment (HOMA) index ≥2.5) and with thyroid uninodular disease were recruited for this study. They were prescribed slow-acting metformin at a daily dose of 500 mg for six months. Treatment with metformin in euthyroid patients with uninodular thyroid disease and insulin resistance reduces TSH levels, increases FT4 and FT3 values, and decreases thyroid and nodule volumes. These data suggest that metformin may be an effective drug not only for the treatment of T2DM and metabolic syndrome, but also for thyroid disease.

Assessment of Maximum Voluntary Ventilation (MVV) in Female Hypothyroids and Its Relationships with Serum TSH and FT4 Levels

Background: Hypothyroidism is a common hormonal disorder affecting various organs including lungs and pulmonary dysfunction in hypothyroid patients has been noted.
 Objective: To observe maximum voluntary ventilation (MVV) in hypothyroid female patients.
 Materials and method: This cross-sectional study was carried out in the Department of Physiology, BSMMU, Dhaka, Bangladesh, from 1st July 2008 to 30th June 2009 on 60 hypothyroid female patients of 30-50 years old. Based on treatment, hypothyroid patients were divided into B1 (untreated patients on their 1st day of diagnosis) and B2 (patients treated for at least 12-18 months). For comparison, 30 age and BMI matched apparently healthy subjects (Group A) were also studied. The study group was selected from the Out Patient Department of Endocrinology, BSMMU, Dhaka, Bangladesh, and the control group was selected by personal contact. Serum TSH and serum FT4 levels were measured by Microparticle Enzyme Immunoassay (MEIA) principle in AxSYM system. Maximum voluntary ventilation (MVV), which is a lung function parameter, was measured by a digital MicroDL spirometer. Data were analyzed by one way ANOVA test, independent sample t-test and Pearson’s correlation coefficient test.
 Results: The mean percentage of predicted values of lung function parameter of MVV in control subjects and treated hypothyroids were within normal ranges. However, this value was significantly lower in untreated hypothyroid subjects in comparison to those of control and treated hypothyroid subjects. In addition, MVV showed negative correlation with serum TSH level and positive correlation with serum FT4 level and these relationships were statistically significant in control group and treated hypothyroid subjects.
 Conclusion: This study reveals that MVV may be lower in untreated hypothyroid female patients compared to control and treated hypothyroids and the deterioration may be positively correlated with serum FT4 level and negatively correlated with serum TSH level. Treatment of hypothyroids may reverse these changes.
 Delta Med Col J. Jul 2020;8(2): 55-60

Gut dysbiosis is associated with primary hypothyroidism with interaction on gut-thyroid axis

Background Previous studies have shown that the gut microbiome is associated with thyroid diseases, including Graves' disease, Hashimoto's disease, thyroid nodules, and thyroid cancer. However, the association between intestinal flora and primary hypothyroidism remains elusive. We aimed to characterize gut microbiome in primary hypothyroidism patients. Methods Fifty-two primary hypothyroidism patients and 40 healthy controls were recruited. The differences in gut microbiota between the two groups were analyzed by 16S rRNA sequencing technology. Fecal microbiota transplantation (FMT) was performed in mice using flora from both groups; changes in thyroid function were then assessed in the mice. Results There were significant differences in α and β diversities of gut microbiota between primary hypothyroidism patients and healthy individuals. The random forest analysis indicated that four intestinal bacteria (Veillonella, Paraprevotella, Neisseria, and Rheinheimera) could distinguish untreated primary hypothyroidism patients from healthy individuals with the highest accuracy; this was confirmed by receiver operator characteristic curve analysis. The short chain fatty acid producing ability of the primary hypothyroidism patients' gut was significantly decreased, which resulted in the increased serum lipopolysaccharide (LPS) levels. The FMT showed that mice receiving the transplant from primary hypothyroidism patients displayed decreased total thyroxine levels. Conclusions Our study suggests that primary hypothyroidism causes changes in gut microbiome. In turn, an altered flora can affect thyroid function in mice. These findings could help understand the development of primary hypothyroidism and might be further used to develop potential probiotics to facilitate the adjuvant treatment of this disease.

Duration of over- and under-treatment of hypothyroidism is associated with increased cardiovascular risk.

Objective To investigate the association between hypothyroidism and cardiovascular disease (CVD) in both treated and untreated hypothyroid patients, and the consequences of over- and under-treatment with respect to cardiovascular risk. Design A registry-based case-control study nested within a population-based cohort of 275 467 individuals with at least one serum thyroid stimulating hormone (TSH) measurement in the period of 1995-2011. Methods Incident cases of CVD were matched with controls according to gender, age and year of birth. Conditional logistic regression analyses were performed to calculate CVD risks associated with exposure to hypothyroidism, with adjustment for 19 pre-existing comorbidities, including cardiovascular disease and diabetes, using the Charlson Comorbidity Index. Results Overall, 20 487 individuals experienced CVD (9.4%, incidence rate 13.1 per 1000 person-years, 95% confidence interval (CI), 13.0-13.3). Risk of CVD was increased in untreated hypothyroidism compared to euthyroidism (odds ratio (OR): 1.83 (95% CI: 1.43-2.35; P < 0.001)). Cardiovascular risk was increased in both treated and untreated hypothyroid individuals per half year of elevated TSH (OR: 1.11 (95% CI: 1.06-1.16; P < 0.001) and OR: 1.15 (95% CI: 1.09-1.23; P = 0.001), respectively). In patients treated with levothyroxine, OR for CVD was 1.12 (95% CI: 1.06-1.18; P < 0.001) for each 6 months of decreased TSH. Conclusion Cardiovascular risk is increased in untreated, but not in treated hypothyroid patients. Among those with treated hypothyroidism, duration of decreased TSH (overtreatment) had a similar impact on cardiovascular risk as duration of elevated TSH (under-treatment), highlighting the importance of initiating treatment and maintaining biochemical euthyroidism in hypothyroid patients in order to reduce the risk of CVD and death.

English

Background: The studies on association between subclinical hypothyroidism and lipid profile have produced conflicting results. The assessment of cardiovascular risk skin subclinical hypothyroid patients are rare in Indian scenario. Aim: To study the lipid profile in subclinical hypothyroid patients and to assess the cardiovascular risk in subclinical hypothyroid patients by using atherogenic indexes. Materials and Methods: In this case - control study newly diagnosed untreated subclinical hypothyroid patients were studied for dyslipidemia and cardiovascular risk is assessed using lipid ratios Athrogenic index of Plasma and Castelli risk index- I and II compared to euthyroid subjects. To find the significant difference between the bivariate samples in Independent groups the Unpaired sample t-test was used and to find the significance in categorical data Chi-Square test and Fisher's Exact was used. In all the above statistical tools the probability value .05 was considered as significant level. Results: Total cholesterol ,triglyceride and VLDL-C levels shows statistically significant association among subclinical hypothyroid patients compared to euthyroid subjects. Castelli risk index-II showed statistically significant association in subclinical hypothyroid patients compared to euthyroid controls. Conclusion: The positive association of subclinical hypothyroid patients and dyslipidemia warrants that all patients with subclinical hypothyroidism should be evaluated for deranged lipid profile paramaters. Castelli risk index-II calculated as LDL-C/HDL-C could be used as a better predictor of cardiovascular risk compared to the other risk assessment ratios Atherogenic index of plasma and Castelli risk index I.

Over- and Under-Treatment of Hypothyroidism Is Associated with Excess Mortality: A Register-Based Cohort Study.

This study investigated the association between hypothyroidism and mortality in both treated and untreated hypothyroid patients, and the consequences of over- and under-treatment with respect to mortality. This was a register-based cohort study of 235,168 individuals who had at least one serum thyrotropin (TSH) during 1995-2011 (median follow-up 7.2 years). Hypothyroidism was defined as at least two measurements of TSH >4.0 mIU/L within a half year spaced by at least 14 days, or one measurement of TSH >4.0 mIU/L and two filled prescriptions of levothyroxine the following year. All-cause mortality rates were calculated using multivariable Cox regression analysis adjusted for age, sex, and comorbidities using the Charlson Comorbidity Index. Mortality was increased in untreated hypothyroid individuals (n = 673; hazard ratio [HR] = 1.46 [confidence interval (CI) 1.26-1.69]; p < 0.001) compared to euthyroid controls. Results remained significant even when subdividing according to mild (TSH >4.0 mIU/L and ≤10 mIU/L; p < 0.001) and marked hypothyroidism (TSH >10 mIU/L; p = 0.002). Mortality was increased in both treated and untreated hypothyroid individuals for each six months a patient had increased TSH (HR = 1.05 [CI 1.02-1.07], p < 0.0001, and HR = 1.05 [CI 1.02-1.07], p = 0.0009, respectively). In patients who received levothyroxine, the HR for mortality increased by a factor 1.18 ([CI 1.15-1.21]; p < 0.0001) for each six months a patient exhibited decreased TSH. This finding was essentially unchanged after stratification by disease severity (mild or marked hypothyroidism) and age (older and younger than 65 years). Mortality was increased in untreated but not in treated hypothyroid individuals, independently of age and severity of hypothyroidism. Duration of decreased TSH in treated individuals had a greater impact on mortality than did duration of elevated TSH. These results stress the need for close monitoring of treatment in individuals receiving thyroid hormone replacement therapy.

Thyroid Hormone Replacement Therapy Improves Olfaction and Taste Sensitivity in Primary Hypothyroid Patients: A Prospective Randomised Clinical Trial.

Smell and taste are known to be influenced by thyroid function changes. However, many hypothyroid patients and physicians are unaware of their dysosmia and dysgeusia. The present study was performed to shed more light on the relation between hypothyroidism and olfactory loss. 32 primary hypothyroid patients and 31 controls enrolled in the prospective randomized interventional study. Newly diagnosed Primary hypothyroid patients were treated with L-thyroxine for 3-6 months. The control group was selected on the basis of the biochemical evidence of a normal thyroid function. Psychophysiological olfactory testing was performed using odor dispensers similar to felt-tip pens ("Sniffin' Sticks", Burghart, Wedel, Germany). Taste function tests were made using "Taste Strips" (Burghart, Wedel, Germany) which are basically tastant adsorbed filter paper strip. Smell identification, threshold, discrimination, TDI scores, bitter and sweet taste scores were significantly lower in untreated hypothyroid patients compared to controls (12.31±1.09 vs. 14.03±1.05, p<0.001; 7.09±1.15 vs. 8.89±1.12, p<0.001; 11.47±0.95 vs. 13.06±0.85, p<0.001; 30.90±2.70 vs. 35.89±2.07, p<0.001; 4.88±1.6 vs. 6.64±0.96, p<0.001; and 5.5±2.22 vs. 6.58±1.28, p=0.021) respectively. Comparison of scores at the third month of treatment and before treatment of hypothyroid patients revealed significant improvement in smell and taste functions in terms of identification, threshold, discrimination, TDI scores, bitter, sweet and salty tastes (12.31±1.09 vs. 13.84±1.22, p<0.001; 7.09±1.15 vs. 8.02±1.16, p<0.001; 11.47±0.95 vs. 12.41±1.21, p<0.001; 30.90±2.70 vs. 34.27±3.25, p<0.001; 4.88±1.6 vs. 6.06±1.4, p<0.001; 5.5±2.22 vs. 6.38±1.28, p<0.001; and 6.12±2.32 vs. 6.62±1.48, p=0.044) respectively. On correlation analysis, there was a negative correlation between TPO-Ab levels and discrimination, identification and TDI scores (r=-0.409, p=0.02; r=-0.424, p=0.016; r=-0.532, p=0.002), and also between Tg-Ab levels and identification, TDI, and bitter scores (r=-0.423, p=0.016; r=-0.468, p=0.007; r=-0.409, p=0.02) respectively. Primary hypothyroidism was found to have a negative effect on smell and taste. RAI treatment was found to be most destructive on smell and taste compared to surgical and autoimmune hypothyroidism. Treatment of hypothyroidism was positively correlated with an improvement of both senses. Thus, the future workup of patients with smell/taste loss should include investigations for thyroid functions.

Native Magnetic Resonance T1-Mapping Identifies Diffuse Myocardial Injury in Hypothyroidism.

Background and AimHypothyroidism (HT) is characterized by thyroid hormone deficiencies, which can lead to diffuse myocardial interstitium lesions in patients with HT. Myocardial longitudinal relaxation time (T1) mapping is a potential diagnostic tool for quantifying diffuse myocardial injury. This study aimed to assess the usefulness of T1 mapping in identifying myocardial involvement in HT, and determine the relationship between T1 values and myocardial function.MethodsA cross-sectional study was conducted with 30 untreated HT patients alongside 23 age- and sex-matched healthy controls. All subjects underwent cardiac magnetic resonance (CMR) with non-contrast (native) T1 mapping using a modified Look-Locker inversion-recovery (MOLLI) sequence to assess the native T1 values of myocardium and cardiac function.ResultsNative myocardial T1 values were significantly increased in HT patients, especially those with pericardial effusion (p < 0.05), compared with healthy controls. In addition, significantly reduced peak filling rate (PFR) and prolonged peak filling time (PFT) were obtained (p < 0.05) in HT patients compared with controls. Furthermore, stroke volume (SV) and cardiac index (CI) were significantly lower in HT patients than controls (all p < 0.05). Interestingly, native T1 values were negatively correlated with free triiodothyronine (FT3), PFR, SV and CI (all p < 0.05).ConclusionDiffuse myocardial injuries are common in HT patients, and increased T1 values are correlated with FT3 and cardiac function impairment. These findings indicate that T1 mapping might be useful in evaluating myocardial injuries in HT patients.

A Double-Blind Placebo-Controlled Trial of Liquid Thyroxine Ingested at Breakfast: Results of the TICO Study.

Levothyroxine (LT4) is the recommended treatment for millions of hypothyroid patients. Current guidelines recommend that LT4 tablets be taken in a fasting state, but inability to adhere to this often leads to poor therapy compliance. A randomized, double-blind, placebo-controlled, crossover trial was conducted in previously untreated hypothyroid patients randomly assigned to receive an oral solution of LT4 either at least 30 minutes before breakfast or directly at breakfast time. Each patient completed two six-week treatment periods, with different timing of active LT4 administration: placebo before breakfast and active LT4 at breakfast, or vice versa. At the end of each period, thyrotropin (TSH), free thyroxine (fT4), and free triiodothyronine (fT3) were measured. The primary endpoint was to verify any difference in serum TSH levels whether consuming liquid LT4 at breakfast or 30 minutes prior to breakfast. A total of 77 patients (64 females; median age 45.4 ± 3.7 years) completed the study. No statistically significant differences in serum TSH, fT4, or fT3 levels were observed whether LT4 was taken at breakfast or 30 minutes before, in a fasting state. No significant effect from the sequence of regimens, breakfast composition, and/or concomitantly administered drugs was observed on the dose of LT4 administered, or on the post-treatment serum TSH values. The TICO study suggests that a liquid LT4 formulation can be ingested directly at breakfast, thus potentially improving therapeutic compliance. This observation is of considerable clinical relevance, since non-adherence to LT4 therapy requirements is more likely to cause variability in serum TSH concentrations.

Simultaneous measurement of serum chemokines in autoimmune thyroid diseases: possible role of IP-10 in the inflammatory response.

Autoimmune thyroid diseases (AITDs), including Graves' diseases (GD) and Hashimoto's thyroiditis (HT), are the most common autoimmune diseases, and are mainly mediated by T cells that produce cytokines and chemokines in abnormal amounts. Few reports have described the circulating chemokines active in AITDs. Recently, we used a new multiplex immunobead assay to simultaneously measure cytokines and chemokines in small volume serum samples from patients with AITDs. We measured 23 selected serum chemokines in patients with GD (n=45) or HT (n=26), and healthy controls (n=9). GD patients were further classified as either untreated, intractable, or in remission, while HT patients were classified as either hypothyroid or euthyroid. Of the 23 serum chemokines assayed, only the serum level of IP-10 (CXCL10/interferon-γ-inducible protein 10) was elevated, depending on disease activity, in GD or HT compared with healthy controls. However, the serum level of IP-10 was also increased in both untreated GD patients and hypothyroid HT patients, suggesting that levels of this cytokine may not be affected by disease specificity. In conclusion, autoimmune inflammation in patients with AITD is closely related to the level of the serum chemokine, IP-10. Therefore, IP-10 might be a good biomarker for tissue inflammation in the thyroid, but not a useful biomarker for predicting disease specific activity, the progression of AITDs, or responsiveness to treatment because of its independence from thyroid function or disease specificity.

A voxel-based morphometry study of gray matter abnormalities in patients with hypothyroidism

Objective To investigate the gray matter volume differences between adult hypothyroid subjects and healthy controls using voxel-based morphometry (VBM). Methods A total of 28 untreated hypothyroid patients and 28 age and gender-matched normal controlswere recruited.The concentrations of their freetriiodothyronine (FT3), free theroxine (FT4), and thyroid stimulating hormone (TSH)were testedfrom their venous blood on the day they accepted MR scanning.High resolution 3D-datawereobtained using 3.0 T MRI scanner. VBM analysis was performed to detect the volume differences between the groups by using voxel-wise two sample t test. Multiple regression analysis was employed to analyze the influence exerted upon gray matter volume by serum FT3, FT4, and TSH concentrationof hypothyroid patients. Results Compared to controls, gray matter volumes in the bilateral superior frontal gyri, left precentralgyrus and bilateral cerebellum were decreased in hypothyroid patients (voxels 211–2 142, t=3.36–3.69, P 0.05) was found in the multiple regression analysis. Conclusions VBM analysis revealed that hypothyroid patients exhibited reduced gray matter volume in multiple brain regions. It suggests that the lack of thyroid hormones can lead to the structural abnormalities in adult brain and selective gray matter atrophy in multiple brain regions. Key words: Hypothyroidism; Magnetic resonance imaging; Brain

Impaired aortic distensibility in hypothyroid patients with negative coronary angiograms: Simultaneous evaluation with 128-slice multiple row detector computed tomography

To determine the relationship between arterial distensibility and hypothyroidism by simultaneous assessment of coronary angiography and aortic distensibility, measured using 128-slice retrospective electrocardiogram-gated multiple row detector computed tomography (MDCT). Untreated hypothyroid patients and age-matched euthyroid patients, who underwent 128-slice retrospective electrocardiogram-gated MDCT to evaluate the coronary arteries, were assessed. Intraluminal aortic areas in systolic and diastolic phases of the cardiac cycle were measured with multiphase reformation at predefined locations including the ascending aorta, proximal descending aorta and distal descending aorta in the widest axial plane. The study included 21 hypothyroid and 21 euthyroid patients. Patients with hypothyroidism exhibited decreased aortic distensibility between each location in the thoracic aorta (ascending aorta, proximal descending aorta and distal descending aorta) compared with euthryoid patients. Hypothyroidism was associated with preclinical vascular alteration, characterized by impaired aortic distensibility at each location of the thoracic aorta, which has been shown to be related to increased cardiovascular risk. Monitoring of aortic distensibility is relevant for evaluating coronary artery disease progression and treatment choices.

Assessment of Autonomic Nerve Function In Hypothyroids By Time Domain Method of Heart Rate Variability

Background: Cardiovascular complications are common in hypothyroids .Time domain measures of HRV is useful to determine the cardiac autonomic regulation by assessing sympathovagal balance.Objective: To assess the cardiac autonomic nerve function activity by time domain measures of heart rate variability in patients with hypothyroidism.Methods: This cross sectional study was carried out in the Department of Physiology, Banghabandhu Sheikh Mujib Medical University between July 2008 to June 2009 on 60 female patients with hypothyroidism aged 30-50 years. 30 age matched apparently healthy euthyroid subjects were also studied as control. Hypothyroid patients were divided into 2 subgroups, one group includes patients on their 1st day of diagnosis, before starting of treatment and another group includes patients with medication for 12-18 months. The patients were selected from the Out Patients Department of Endocrinology Wing BSMMU. Serum TSH and FT4 levels of all subjects were measured by AxSYM system. For assessing HRV by time domain method, mean R-R interval, mean heart rate, SDNN, RMSSD and variance were measured by a Polyrite. For statistical analysis, Independent Sample t test and One Way ANOVA were used.Results: The mean serum TSH was significantly higher and FT4 was significantly lower (p&lt;0.001) in newly diagnosed hypothyroids than those of control and treated group. In untreated hypothyroid patients the mean values of heart rate, SDNN, RMSSD,variance were found significantly (p&lt;0.001) lower in comparison to both control and treated patients. No significant difference in these hormonal levels and all these time domain measures were found between control and treated group.Conclusion: This study concludes that decrease parasympathetic nerve activity may be a consequence of hypothyroidism, if not treated properly. DOI: http://dx.doi.org/10.3329/jbsp.v7i1.11162 J Bangladesh Soc Physiol. 2012, June; 7(1): 48-52

Etiology of anemia in primary hypothyroid subjects in a tertiary care center in Eastern India

Introduction:The association of anemia with primary hypothyroidism has been common knowledge for many years. However; its pathogenesis is far from clear in many cases. Often the causes of anemia are manifold.Aims and objectives:In this study, we evaluated the causes of anemia in patients with primary hypothyroidism.Materials and Methods:Sixty adult nonpregnant untreated primary hypothyroid patients with anemia without any obvious cause were included. All patients were subjected to full medical history, clinical examination, biochemical and imaging studies. Serum iron profile, vitamin B12, folic acid, anti parietal cell antibody, anti TPO antibody, bone marrow study, and stool for occult blood, Coomb's test, HPLC for hemoglobinopathies and complete hemogram with reticulocyte count were done and analyzed.Results:Normocytic, normochromic anemia was present in 31 patients (51.6%) followed by microcytic anemia in 26 patients (43.3%). Six patients (10%) had megaloblastic anemia with vitamin B12 deficiency including 3 cases of pernicious anemia. Two patients had combined deficiency of iron and vitamin B12.Conclusion:Normocytic normochromic anemia with normal bone marrow was commonest type of anemia in this study, followed by iron deficiency anemia.

Variation in thyroid function in subclinical hypothyroidism: importance of clinical follow-up and therapy

Subclinical hypothyroidism (SCH) is a common condition that is often observed without therapy. However, no evidence-based recommendation exists with regards to how patients with untreated SCH should be monitored. Monitoring involves regular assessment of symptoms and signs of hypothyroidism (HYPO) and biochemical tests of thyroid function. An important question when repeated tests of thyroid function are performed is how large a difference in test results is needed to be confident that the change is real and not just due to chance variation. Recent data show that the least significant difference between two tests in SCH is 40% for TSH and 15% for free thyroxine and free triiodothyronine, with 90% confidence. Furthermore, monitoring has to be based on biochemical function testing because serial evaluation of symptoms and signs related to HYPO is rather insensitive in detecting worsening of thyroid insufficiency. When the presence of thyroid peroxidase auto-antibodies (TPO-Ab) in serum has been demonstrated, repeated measurements do not add much useful information in the monitoring of individual subclinical hypothyroid patients, as levels of TPO-Ab vary in parallel with TSH in these patients. Lastly, we discuss how differences in the monitoring procedure influence the diagnostic outcome, and we suggest a follow-up approach for untreated subclinical hypothyroid patients.

Hypothyroidism and the Risk of Developing Open-Angle Glaucoma: A Five-Year Population-Based Follow-up Study

To investigate the risk of open-angle glaucoma (OAG) after a diagnosis of hypothyroidism. A retrospective, population-based follow-up study using an administrative database. The study group comprised 257 hypothyroidism patients. The comparison group included 2056 subjects. Data were retrospectively collected from the Taiwan Longitudinal Health Insurance Database. The study cohort comprised patients aged ≥ 60 who received a first diagnosis of hypothyroidism (International Classification of Diseases, Ninth Revision, Clinical Modification code 244.9) from 1997 to 2001 (n = 257). The comparison cohort consisted of randomly selected patients without hypothyroidism who were aged ≥ 60 and had no diagnosis of glaucoma before 2001 (8 for every OAG patient; n = 2056). Each sampled patient was tracked for 5 years from their index visit. Cox proportional hazard regressions were used to compute the 5-year OAG-free survival rate, after adjusting for possible confounding factors. The risk of developing OAG during the 5-year follow-up period. Open-angle glaucoma developed in 7.4% of patients with hypothyroidism and 3.8% of patients in the comparison cohort during the follow-up period. Hypothyroid patients had a significantly lower 5-year OAG-free survival rate than patients in the comparison cohort. After adjusting for patients' age, gender, monthly income, urbanization level, and comorbid medical disorders, hypothyroidism patients were found to have a 1.78-fold (95% confidence interval [CI], 1.04-3.06) greater risk of developing OAG than the comparison cohort. This association remained significant in untreated hypothyroidism patients (adjusted hazard ratio [HR], 2.37; 95% CI, 1.10-5.09) and became statistically nonsignificant in patients treated with levothyroxine (adjusted HR, 1.73; 95% CI, 0.89-3.38). Hypothyroid patients had a significantly increased risk of OAG development during the 5-year follow-up period. Levothyroxine seemed to be protective.