Reduced thyroid volume and nodularity in dyslipidaemic patients on statin treatment

Genetic insights into repurposing statins for hyperthyroidism prevention: a drug-target Mendelian randomization study

Background

Current therapeutic measures for thyroid dysfunction are limited and often accompanied by adverse effects. The use of lipid-lowering drugs like statins has recently been associated with lower thyroid eye diseases risk.

Objective

To investigate the implications of genetically proxied lipid-lowering drugs on thyroid dysfunction.

Methods

In this drug-target Mendelian randomization (MR) study, we utilized genetic variants within drug target genes associated with low-density lipoprotein (LDL) or triglyceride (TG), derived from a genome-wide association study (GWAS) meta-analysis (N ≤ 188,577), to simulate lifelong drug interventions. Genetic summary statistics for thyroid dysfunction outcomes were retrieved from GWAS datasets of Thyroid Omics Consortium (N ≤ 54,288) and UK Biobank (N = 484,598). Inverse-variance-weighted MR (IVW-MR) method was performed as primary analysis, followed by validation in colocalization analysis. A subsequent two-step MR analysis was conducted to identify biomarkers mediating the identified drug-outcome association.

Results

In IVW-MR analysis, genetic mimicry of 3-hydroxy-3-methylglutarylcoenzyme reductase (HMGCR) inhibitors (e.g. statins) was significantly associated with lower risk of hyperthyroidism in two independent datasets (OR1, 0.417 per 1-mmol/L lower in LDL-C; 95% CI 0.262 to 0.664; P1 = 2.262 × 10-4; OR2 0.996; 95% CI 0.993-0.998; P2 = 0.002). Two-step MR analysis revealed eighteen biomarkers linked to genetic mimicry of HMGCR inhibition, and identified insulin-like growth factor 1 (IGF-1) levels mediating 2.108% of the negative causal relationship between HMGCR inhibition and hyperthyroidism.

Conclusion

This study supports HMGCR inhibition as a promising therapeutic strategy for hyperthyroidism and suggests its underlying mechanisms may extend beyond lipid metabolism. Further investigations through laboratory studies and clinical trials are necessary to confirm and elucidate these findings.

Ultrasound of benign thyroid nodules: A 120 months follow-up study

OBJECTIVE

Some evidence suggests that most benign nodules exhibit no significant size increase during 5 years of follow-up, although conflicting results have emerged. The aim of the present study is to evaluate the frequency and the magnitude of growth in benign nodules during 120 months of follow-up.

DESIGN

We reviewed the medical and imaging records of patients who were submitted to ultrasound-guided FNA of thyroid nodules at our hospital from January 2007 to March 2009. We selected only patients with benign nodules who underwent annual ultrasound evaluation in our Department.

RESULTS

Among 966 selected patients, 289 were lost during follow-up, meaning that the total number of patients analysed was 677 (474 women and 203 men), with a mean age of 45.6 (16-71) years. In 559/677 patients (82.7%), the size of the nodule remained stable during follow-up; 42 (6.2%) patients experienced spontaneous nodule shrinkage, and 75 (11.1%) patients showed nodule growth. Patients with or without nodule growth during follow-up were superimposable at baseline for age, gender, TSH values, number of patients on levothyroxine treatment and nodule characteristics. All baseline variables in predicting nodular growth were entered to an adjusted multivariate logistic regression model. None of the parameters taken into account was associated with nodular growth.

CONCLUSIONS

In conclusion, the majority of benign nodules remained stable over the period of monitoring. On the basis of our experience, we recommend ultrasound examination at a distance of 2 and 5 years following cytological evaluation, then every 4-5 years from then on.

Evaluation of the relationship between previous statin use and thyroid cancer using Korean National Health Insurance Service-Health Screening Cohort data

The association of thyroid cancer with statin use is controversial. This study aimed to investigate the association of previous statin use with thyroid cancer in the ≥ 40-year-old population in the Korean National Health Insurance Service-Health Screening Cohort. The 5501 patients in the thyroid cancer group were matched with the 22,004 patients in the non-thyroid cancer group for age, sex, income, and region of residence. Previous statin use during the 2 years before the diagnosis of thyroid cancer was examined. The odds ratios (ORs) with 95% confidence intervals (CIs) of previous statin use for thyroid cancer were estimated using conditional logistic regression analyses. Additionally, subgroup analyses were conducted. The thyroid cancer group showed more days of previous statin use than the non-thyroid cancer group (72.3, standard deviation [SD] = 181.2 days vs. 64.3, SD = 174.4 days, P = 0.003). Although the odds of previous statin use for thyroid cancer were high in the crude model (OR = 1.10, 95% CI 1.04–1.17, P = 0.002), they were low in the fully adjusted model (OR = 0.89, 95% CI 0.82–0.95, P = 0.001). According to age and sex subgroups, the younger (< 60 years old) male group showed lower odds for thyroid cancer according to previous statin use (adjusted OR = 0.70, 95% CI 0.55–0.88, P = 0.003), but this finding was not observed in other subgroups of older men or in any groups of women. Thyroid cancer was negatively associated with statin use in the previous 2 years in the adjusted model.

Is Statin Use Associated With Risk of Thyroid Diseases? Results of a Retrospective Cohort Study

BACKGROUND

Given the ubiquity of statin use and prevalence of thyroid diseases, such as thyroid cancer, hyperthyroidism, and thyroiditis, understanding their association deserves further attention.

OBJECTIVE

To examine the association between statin use and thyroid cancer, thyrotoxicosis, goiter, and thyroiditis.

METHODS

Using Tricare data, 2 propensity score (PS)-matched cohorts of statin users and nonusers were formed: (1) a PS-matched general cohort (all patients aged 30-85 years) and (2) a PS-matched healthy cohort (excluded patients with cardiovascular diseases or severe comorbidities). Outcomes were thyroid cancer, thyrotoxicosis, goiter, and thyroiditis. Odds ratios (ORs) and 95% CIs of outcomes were estimated using conditional regression analysis.

RESULTS

Of 43 438 patients, the PS-matched general cohort matched 6342 statin users to 6342 nonusers. The OR of thyroid cancer was 0.62 (95% CI = 0.39-0.996). There was no significant difference between statin users and nonusers in risk of thyrotoxicosis (OR = 0.88; 95% CI = 0.71-1.09), goiter (OR = 0.9; 95% CI = 0.77-1.03), or thyroiditis (OR = 0.78; 95% CI = 0.53-1.15). In the PS-matched healthy cohort (3351 statin users to 3351 nonusers), there was no difference between statin users and nonusers in any outcome. Limitations of the study include its retrospective observational design and use of administrative codes in outcomes ascertainment.

CONCLUSION AND RELEVANCE

This study did not demonstrate any association of statins with harmful effects on thyroid diseases, which offers assurance to clinicians and patients. Furthermore, statin use appears to be associated with a decreased risk of thyroid cancer, but more studies are needed.

Thyroid scintigraphy in the era of fine-needle aspiration cytology

PURPOSE

To evaluate whether thyroid scintigraphy would alter the clinical management of patients referred for fine-needle aspiration cytology (FNA).

METHODS

We reviewed the medical and imaging records of patients referred to our Department between 2016 and 2019. All the patients had to take a serum thyrotropin test administered in our hospital at least two months before the FNA; where the TSH level was ≤1.5 mIU/L, the patients were subjected to a scan and subsequently to FNA, where indicated. We selected only healthy patients with no previous history of thyroid disease, who were not taking any drugs and who had a TSH level of ≤1.5 mIU/L. We excluded patients with multinodular goitre.

RESULTS

A total of 176 patients were analysed. A total of 67/176 patients (38%) showed a serum of TSH ≤ 0.27 mIU/L. Scintigraphy identified a hot nodule in 142 lesions (80.7%), a warm nodule in 8 lesions (4.5%) and a cold nodule in 26 lesions (14.8%). The ROC curve analysis indicated that a TSH value of ≤0.42 mIU/L identified patients with hyperfunctioning nodules with a sensitivity of 65% and a specificity of 77%. All patients with cold and warm nodules were submitted to FNA: 22/26 (85%) and 5/8 (63%) lesions showed suspected malignancy or were compatible with malignancy, respectively.

CONCLUSION

Speculating on our data, if we had subjected our patients to FNA as indicated by the 2015 ATA guidelines, we would have subjected 117 patients to cytology, from whom 83 had undetected hot nodules. Conversely, by adopting scintigraphy for all patients with TSH ≤ 1.5 mIU/L, 109 patients have avoided FNA. However, our study was performed in a region with a history of mild iodine deficiency. Therefore, we cannot claim that our observation is valid for patients born and living in areas with sufficient iodine uptake. We recommend thyroid scintigraphy for treating single thyroid nodules in euthyroid patients born and living in regions with an iodine deficiency, when TSH levels are below 1.5 mIU/L before FNA.

Open-source chemogenomic data-driven algorithms for predicting drug-target interactions

While novel technologies such as high-throughput screening have advanced together with significant investment by pharmaceutical companies during the past decades, the success rate for drug development has not yet been improved prompting researchers looking for new strategies of drug discovery. Drug repositioning is a potential approach to solve this dilemma. However, experimental identification and validation of potential drug targets encoded by the human genome is both costly and time-consuming. Therefore, effective computational approaches have been proposed to facilitate drug repositioning, which have proved to be successful in drug discovery. Doubtlessly, the availability of open-accessible data from basic chemical biology research and the success of human genome sequencing are crucial to develop effective in silico drug repositioning methods allowing the identification of potential targets for existing drugs. In this work, we review several chemogenomic data-driven computational algorithms with source codes publicly accessible for predicting drug-target interactions (DTIs). We organize these algorithms by model properties and model evolutionary relationships. We re-implemented five representative algorithms in R programming language, and compared these algorithms by means of mean percentile ranking, a new recall-based evaluation metric in the DTI prediction research field. We anticipate that this review will be objective and helpful to researchers who would like to further improve existing algorithms or need to choose appropriate algorithms to infer potential DTIs in the projects. The source codes for DTI predictions are available at: https://github.com/minghao2016/chemogenomicAlg4DTIpred.

The Pleiotropic Effects of Statins in Endocrine Disorders

BACKGROUND

The 3-Hydroxy-3-MethylGlutaryl-CoA reductase inhibitors, better known as statins, are used extensively in the treatment of dyslipidemia and cardiovascular risk reduction. They have also demonstrated a variety of non-lipid lowering, or pleiotropic effects. Pertaining to the endocrine system the benefits of statins can extend to patients with the polycystic ovarian syndrome and thyroid disease. However, there is also increasing evidence that statin use can lead to deleterious effects in different organs, including worsening glycemia and the development of diabetes mellitus.

OBJECTIVE

The aim of this review is to describe the most relevant and updated evidence regarding the pleiotropic effects of statins in endocrine disorders.

METHODS

We did a systematic review of scientific articles published in PubMed regarding the effects of statins on the different aspects of the endocrine system up until June 5th of 2018.

RESULTS

We identified preliminarily 61 publications, of which 4 were excluded due to having abstract format only, and 5 were excluded for not containing pertinent information to the study.

CONCLUSION

Several aspects of the endocrine system have been shown to be influenced by the pleiotropic effects that statins exert, however, the benefits of statins on cardiovascular morbidity and mortality largely outweigh this deleterious effect, and statin therapy should continue to be recommended.

Thyroid volumes and serum VEGF levels in dyslipidemic patients: effects of statin treatment

Background/aim

Defective vascularization may be important in thyroid nodular disease. In this study, we aimed to investigate serum vascular endothelial growth factor (VEGF) levels in dyslipidemic patients with thyroid nodules, as well as the effects of statin therapy.

Materials and methods

The study included 37 dyslipidemic patients with thyroid nodules and 32 dyslipidemic patients without thyroid nodules. Anthropometry, serum VEGF levels, biochemical parameters, thyroid-stimulating hormone (TSH), free triiodothyronine (fT3) and free thyroxine (fT4) levels, and thyroid sonography were determined before and after 6 months of statin therapy.

Results

Patients with and without thyroid nodules had similar metabolic parameters. Serum VEGF levels did not differ between the groups. In patients with nodules, VEGF levels remained unchanged (P = 0.931) after statin therapy. However, serum VEGF levels were lowered by statin treatment in patients without nodules (P = 0.030). Statin therapy resulted in a decrease in the dominant thyroid nodule volume. The changes in thyroid volume and dominant thyroid nodule volume were not correlated with changes in VEGF, body mass index, total cholesterol, low-density lipoprotein cholesterol, or homeostatic model assessment of insulin resistance (HOMA-IR).

Conclusion

Although statin treatment decreases serum VEGF levels in dyslipidemic patients without thyroid nodules, it has no lowering effect on serum VEGF levels in patients with thyroid nodules. The decrease in thyroid nodule volume with statin treatment was associated with neither metabolic parameters nor serum VEGF levels.

Evaluation of Thyroid Nodules

This is a brief overview of the initial workup of patients with thyroid nodules. Most nodules are incidentally discovered, benign, and do not require surgery, but the clinician's job is to determine which nodules are concerning and what the appropriate workup should be. Ultrasound examination is the best imaging modality to evaluation thyroid nodules and, when biopsy is indicated, fine needle aspiration is the proper technique to sample thyroid nodules.

Ultrasound Microvascular Blood Flow Evaluation: A New Tool for the Management of Thyroid Nodule?

BACKGROUND

Toshiba Medical System has developed a new Doppler technique [Superb Microvascular Imaging (SMI)] that has improved microvascular flow imaging. SMI depicts perinodular and intranodular thyroid microvascular flow in higher detail compared to standard colour Doppler (CD) and power Doppler (PD) imaging.

OBJECTIVE

Assess the nodular microvascular architecture by SMI compared to CD and PD features in a series of thyroid nodules submitted to fine needle aspiration cytology, in order to evaluate the potential of SMI in detecting thyroid cancer.

MATERIALS AND METHODS

From April 2016 to July 2017, 254 patients with thyroid nodules, evaluated as at high risk for malignancy in agreement with AACE/ACE/AME guidelines, were submitted to cytology. All nodules were previously submitted to ultrasound grayscale, CD, PD, and SMI evaluation. Benign and malignant nodules were stratified in accordance to the number of vessels visualised by SMI: score 1 with a maximum of two blood vessels and score 2 with three or more vessels.

RESULTS

Score 1 was found in 59.6% of benign nodules and in 17.9% of malignant nodules, whereas score 2 was found in 40.4% and in 82.1%, respectively (sensitivity 81.7%; specificity 60.5%, p < 0.001). Variables significantly associated with malignancy in the univariate analysis were gender (OR, 0.18; 95% CI, 0.08-0.37; p < 0.001), vascularity (OR, 1.91; 95% CI, 1.65-3.89; p < 0.001), and SMI (OR, 6.72; 95% CI, 3.89-11.59; p < 0.001); multivariate logistic model confirmed SMI score 2 as an independent risk factor for malignancy (OR, 6.99; 95% CI, 3.46-12.09; p < 0.001).

CONCLUSIONS

This prospective pilot study showed that SMI can depict intranodular flow in higher detail compared to CDI and PDI, thus improving thyroid cancer detection.

Do Statins Affect Thyroid Volume and Nodule Size in Patients with Hyperlipidemia in a Region with Mild-to-Moderate Iodine Deficiency? A Prospective Study

OBJECTIVE

The objective of this study was to assess the antiproliferative pleiotropic effects of statins on thyroid function, volume, and nodularity.

SUBJECTS AND METHODS

One hundred and six hyperlipidemic patients were included in this prospective study. The 69 patients in the statin groups received atorvastatin (16 received 10 mg and 18 received 20 mg) or rosuvastatin (20 received 10 mg and 15 received 20 mg). The 37 patients in the control group, assessed as not requiring drugs, made only lifestyle changes. Upon admission and after 6 months, all patients were evaluated by ultrasonography as well as for lipid variables (total cholesterol, high- and low-density lipoprotein cholesterol, and triglycerides) and thyroid function and structure.

RESULTS

After 6 months, no differences in thyroid function, thyroid volume, the number of thyroid nodules, or nodule size were observed in the statin and control groups. In a subgroup analysis, total thyroid volume had decreased more in patients receiving 20 mg of rosuvastatin than that in the control group (p < 0.05). Maximum nodule size had decreased more in those receiving 10 mg of rosuvastatin (p < 0.05).

CONCLUSIONS

Our results suggest an association between rosuvastatin treatment and smaller thyroid volume and maximum nodule diameter; this could be attributable to the antiproliferative effects of statin therapy on the thyroid.

Predicting drug-target interactions by dual-network integrated logistic matrix factorization

In this work, we propose a dual-network integrated logistic matrix factorization (DNILMF) algorithm to predict potential drug-target interactions (DTI). The prediction procedure consists of four steps: (1) inferring new drug/target profiles and constructing profile kernel matrix; (2) diffusing drug profile kernel matrix with drug structure kernel matrix; (3) diffusing target profile kernel matrix with target sequence kernel matrix; and (4) building DNILMF model and smoothing new drug/target predictions based on their neighbors. We compare our algorithm with the state-of-the-art method based on the benchmark dataset. Results indicate that the DNILMF algorithm outperforms the previously reported approaches in terms of AUPR (area under precision-recall curve) and AUC (area under curve of receiver operating characteristic) based on the 5 trials of 10-fold cross-validation. We conclude that the performance improvement depends on not only the proposed objective function, but also the used nonlinear diffusion technique which is important but under studied in the DTI prediction field. In addition, we also compile a new DTI dataset for increasing the diversity of currently available benchmark datasets. The top prediction results for the new dataset are confirmed by experimental studies or supported by other computational research.

Etiopathology, clinical features, and treatment of diffuse and multinodular nontoxic goiters

Goiter, an enlargement of the thyroid gland, is a common problem in clinical practice associated with iodine deficiency, increase in serum thyroid-stimulating hormone (TSH) level, natural goitrogens, smoking, and lack of selenium and iron. Evidence suggests that heredity also has an important role in the etiology of goiter. The current classification divides goiter into diffuse and nodular, which may be further subdivided into toxic (associated with symptoms of hyperthyroidism, suppressed TSH or both), or nontoxic (associated with a normal TSH level). Nodular thyroid disease with the presence of single or multiple nodules requires evaluation due to the risk of malignancy, toxicity, and local compressive symptoms. Measurement of TSH, accurate imaging with high-resolution ultrasonography or computed tomography, and fine-needle aspiration biopsy are the appropriate methods for evaluation and management of goiter. This review discusses the clinical presentation, diagnostic evaluation, and treatment considerations of nontoxic diffuse and nodular goiters.

The effect of statin therapy on thyroid autoimmunity in patients with Hashimoto's thyroiditis: A pilot study

BACKGROUND

Statins have been found to exert antiinflammatory and immunomodulatory properties. The aim of this study was to compare the effects of intensive and less aggressive statin treatment on thyroid autoimmunity and hypothalamic-pituitary-thyroid axis activity in patients with Hashimoto's thyroiditis.

METHODS

The study included 38 adult women with Hashimoto's thyroiditis, who required statin therapy and were allocated into one of two groups. Patients at very high cardiovascular risk (n=16) received intensive statin treatment (rosuvastatin 20-40mg daily), while patients at moderate or moderately high cardiovascular risk (n=22) were treated with simvastatin (20-40mg daily) for the following 6 months. Serum levels of thyrotropin, total and free thyroid hormones, and high-sensitivity C-reactive protein (hsCRP), as well as titers of thyroid peroxidase and thyroglobulin antibodies were measured at the beginning and at the end of the study.

RESULTS

Thirty-six individuals completed the study and were included in the final analyses. Apart from improving plasma lipids and reducing circulating levels of hsCRP, intensive, but not less aggressive, statin therapy reduced thyroid peroxidase and thyroglobulin antibody titers, as well as tended to reduce circulating levels of thyrotropin. The effect of intensive statin therapy on thyroid antibody titers was lipid-independent but correlated with treatment-induced changes in thyrotropin and hsCRP.

CONCLUSIONS

Although 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors are able to reduce thyroid autoimmunity in women with Hashimoto's thyroiditis, intensive statin therapy is required to produce this effect.

An Epidemiological Study of Risk Factors of Thyroid Nodule and Goiter in Chinese Women

Thyroid nodule (TN) and goiter are two common disorders of the thyroid. Despite their benign nature, both conditions can be associated with multiple pathologic conditions including thyroid cancer. In this study, we conducted a large-scale epidemiological study in Chinese women to identify the risk factors implicated in the occurrence of TN and goiter. We analyzed demographic data, lifestyle, medical history, body height, weight, waist circumference, body mass index (BMI), blood pressure, serum glucose and lipids. In addition, thyroid ultrasonography was performed for all subjects. Our results showed that age, menopause, waist circumference, BMI, hypertension, dyslipidemia, and hyperglycemia were associated with both TN and goiter. Furthermore, we found that the prevalence of TN was significantly affected by the medical management of hypertension. Our study suggests that postmenopausal Chinese women with advanced age, obesity, diabetes, and hypertension have an increased awareness of thyroid examination in the annual physical check. Conversely, patients with TN and goiter of the same population may have a higher incidence of age- and obesity-related metabolic disorders.

Repositioning therapy for thyroid cancer: new insights on established medications

Repositioning of established non-cancer pharmacotherapeutic agents with well-known activity and side-effect profiles is a promising avenue for the development of new treatment modalities for multiple cancer types. We have analyzed some of the medications with mechanism of action that may have relevance to thyroid cancer (TC). Experimental in vitro and in vivo evidences, as well as results of clinical studies, have indicated that molecular targets for medications currently available for the treatment of mood disorders, sexually transmitted diseases, metabolic disorders, and diabetes may be active and relevant in TC. For instance, the derivatives of cannabis and an anti-diabetic agent, metformin, both are able to inhibit ERK, which is commonly activated in TC cells. We present here several examples of well-known medications that have the potential to become new therapeutics for patients with TC. Repositioning of established medications for the treatment of TC could broaden the scope of current therapeutic strategies. These diverse treatment choices could allow physicians to provide an individualized approach to optimize treatment for patients with TC.

Hypothyroidism as a risk factor for statin intolerance

BACKGROUND

Three-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) are one of the most commonly prescribed classes of medications because of their proven cardiovascular benefits. However, statin intolerance occurs in 5% to 20% of patients. Understanding the basis for statin intolerance remains a key issue in preventive medicine.

OBJECTIVES

To evaluate the association of statin intolerance with hypothyroidism in a large integrated health care system, including its sex-specific relationship and subsequent statin rechallenge and prescription history.

METHODS

The Intermountain Healthcare electronic medical record database identified patients (n = 2686; males = 1276, females = 1410) with a documentation of intolerance ("allergy") to at least 1 statin. Age and sex similar controls (n = 8103; males = 3892, females = 4211) were identified among patients prescribed statins without documented intolerance. Patients were evaluated for a history of hypothyroidism, development of hypothyroidism, and statin prescription history up to 5 years of follow-up.

RESULTS

A total of 30.2% patients (210 males, 16.5%; 602 females, 42.7%) with statin intolerance had a history of hypothyroidism compared with 21.5% of statin-tolerant patients (475 males, 12.2%; 1266 females, 30.1%), for an odds ratio (OR) in the total population of 1.49 (95% confidence interval [CI] 1.34-1.65; P < .0001); in males, OR was 1.29 (CI 1.07-1.55; P = .001); in females, OR was 1.60 (CI 1.41-1.82; P < .0001). During follow-up, patients with statin intolerance and hypothyroidism were less likely to be on a statin than their statin-intolerant counterparts without hypothyroidism (hazard ratio 0.84; 95% CI 0.75-0.94; P = .002).

CONCLUSIONS

Hypothyroidism is more prevalent in those with statin intolerance, both in males and, especially, in females. People with hypothyroidism are less likely to have a prescription for a statin at follow-up than those without hypothyroidism.

Morbid obesity in women is associated to a lower prevalence of thyroid nodules

BACKGROUND

Few studies have recently showed functional and morphological changes of the thyroid gland in relation to obesity. To our knowledge, no data are available about the prevalence of thyroid nodules in female obese patients. The aim of this study was to investigate the prevalence of thyroid nodules in morbidly obese women.

METHODS

One hundred eight consecutive female obese patients were selected from those referred to our medical and surgery outpatients providing that following criteria were satisfied: (1) affected by morbid obesity (body mass index (BMI) >40 kg/m(2)); (2) no previous diagnosis of thyroid disease; (3) biochemically proven euthyroid state at the time of recruitment. Ninety-seven control subjects, constituted by normo-weight and/or slightly overweight (BMI ≤ 30 kg/m(2)) women, should satisfy the above criteria 2 and 3. All the subjects were submitted to ultrasound investigation.

RESULTS

The two groups of patients displayed no differences for age and fT4 levels. Obese patients clearly showed a lower prevalence of thyroid nodules [odds ratio 0.294, 95% confidence interval 0.206-0.382]. A single nodule was found in 23% of obese patients as compared to 65% of control subjects (p < 0.0001). No difference for age (year) was found between obese and non-obese subjects with nodules (40.5 ± 8.2 vs. 44.2 ± 8.9, respectively, p = 0.07).

CONCLUSIONS

Our data clearly show a significantly lower prevalence of thyroid nodules in morbidly obese patients. Further studies are needed to confirm and to understand this first observation.

The relationship between thyroid nodules and uterine fibroids

Previous studies suggested that estrogen might have an important role in thyroid nodule formation. Besides, it was recently reported that women with uterine fibroids, which estrogen has effects on, had an increased incidence of thyroid nodules. Our study was to identify the relationship between uterine fibroids and thyroid nodules and to find the factors that may have influences on the occurrence of thyroid nodules. We reviewed the records of 1144 participants who attended health check-ups from 2005 to 2008. Evaluated clinical variables included the size and number of thyroid nodules, presence of uterine fibroids, menopausal status, BMI, smoking, alcohol, medication status, serum levels of cholesterol, LH, FSH, and estradiol. A total of 925 participants were included and 163 (17.6%) subjects had thyroid nodules and uterine fibroids simultaneously. A significant association between both diseases existed (P=0.010), and closer relationship was observed in premenopausal women (n=445, P=0.001). In univariate analysis of systemic E2 level and the incidence of thyroid nodule in premenopausal women, systemic E2 levels had inverse correlation with the incidence of thyroid nodules (P=0.024, OR=0.631, CI: 0.424-0.940). In multivariate logistic regression analysis, older age and the presence of uterine fibroids were the independent factors for the presence of thyroid nodules. Our study suggested that uterine fibroids in women were definitely associated with thyroid nodules and estrogen might have a pivotal role in occurrence of both uterine fibroids and thyroid nodules.

Radioiodine studies, low serum thyrotropin, and the influence of statin drugs

BACKGROUND

A low serum thyrotropin (TSH) concentration is an excellent predictor of hyperthyroidism, either overt or subclinical. Whether statin use influences the ability of a low serum TSH measurement to detect hyperthyroidism has not been evaluated.

METHODS

In a cohort of 307 patients with low or undetectable serum TSH concentrations suggestive of hyperthyroidism, we determined whether concurrent statin use influenced the results of radioiodine uptakes and scans. Participants included 29 patients taking a statin medication and 278 who were not taking a statin. Radioiodine uptakes and scans were interpreted by board-certified nuclear medicine physicians.

RESULTS

Sixteen of the 29 patients who were taking a statin (55%) had normal radioiodine uptakes and scans despite their low serum TSH. The remaining 13 low-TSH patients who were taking a statin (45%) had abnormal uptakes and scans, most commonly showing diffuse thyroid hyperplasia with increased radioiodine uptake. In contrast, the vast majority of the 278 patients not taking a statin had abnormal uptakes and scans (84%), while only 16% of them had normal uptakes and scans (p < 0.001 vs. those on statins). The age- and sex-adjusted odds ratio of a statin user with a low serum TSH having normal radioiodine studies (as opposed to abnormal studies) was 3.6 (95% CI, 1.6-8.4).

CONCLUSION

In patients with a low serum TSH concentration, normal thyroid function and morphology, as assessed by radioiodine studies, were much more common if the patient was taking a statin. Statins may falsely lower the serum TSH without altering thyroid function ("pseudohyperthyroidism") or, alternatively, statins may improve thyroid function in patients with hyperthyroidism.