Subclinical hyperthyroidism in patients with type 2 diabetes

Prevalence of thyroid dysfunction and associated factors among adult type 2 diabetes mellitus patients, 2000-2022: a systematic review and meta-analysis

BACKGROUND

Thyroid dysfunction (TD) and type 2 diabetes mellitus (T2DM) frequently co-occur and have overlapping pathologies, and their risk increases with age. Thyroid dysfunction along with T2DM will worsen macro- and microvascular complications, morbidity, and mortality.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guideline was followed. The databases used were Embase, ScienceDirect, PubMed, and Google Scholar. The Joana Briggs Institute (JBI) scale was used to assess the quality of the included studies. The data was extracted by Microsoft Excel and analyzed through STATA version 14 software. The overall pooled prevalence of TD and its main components were estimated using the random-effects model. The consistency of studies was assessed by I2 test statistics. Pooled meta-logistic regression was used to present the pooled prevalence with a 95% confidence interval (CI). Besides, subgroup and sensitivity analyses were employed.

RESULT

Thirty-eight studies were included. The pooled prevalence of TD was 20.24% (95% CI: 17.85, 22.64). The pooled prevalence of subclinical hypothyroidism, hypothyroidism, subclinical hyperthyroidism, and hyperthyroidism was found to be 11.87% (95% CI: 6.90, 16.84), 7.75% (95% CI: 5.71, 9.79), 2.49% (95% CI: 0.73, 4.25), and 2.51% (95% CI: 1.89, 3.13), respectively. Subgroup analysis based on continent revealed a higher prevalence of TD in Asia and Africa. Factors like being female, HbA1c ≥ 7%, DM duration > 5 years, family history of TD, central obesity, smoking, the presence of retinopathy, and neuropathy were found associated with TD.

CONCLUSION

The current systematic review and meta-analysis showed that the TD's pooled prevalence was relatively higher than the general population. Therefore, regular screening of TD should be done for T2DM patients.

Hyperthyroidism and cardiovascular disease: an association study using big data analytics

BACKGROUND

The cardiovascular (CV) system is profoundly affected by thyroid hormones. Both hypo- and hyperthyroidism can increase the risk of severe CV complications.

OBJECTIVE

To assess the association of hyperthyroidism with major CV risk factors (CVRFs) and CV diseases (CVDs) using a big data methodology with the Savana Manager platform.

MATERIAL AND METHODS

This was an observational and retrospective study. The data were obtained from the electronic medical records of the University Hospital Puerta de Hierro Majadahonda (Spain). Artificial intelligence techniques were used to extract the information from the electronic health records and Savana Manager 3.0 software was used for analysis.

RESULTS

Of a total of 540,939 patients studied (53.62% females; mean age 42.2 ± 8.7 years), 5504 patients (1.02%; 69.9% women) had a diagnosis of hyperthyroidism. Patients with this diagnosis had a significantly (p < 0.0001) higher frequency of CVRFs than that found in non-hyperthyroid subjects. The higher frequency of CVRFs in patients with hyperthyroidism was observed in both women and men and in patients younger and older than 65 years of age. The total frequency of CVDs was also significantly (p < 0.0001) higher in patients diagnosed with hyperthyroidism than that found in patients without this diagnosis. The highest odds ratio values obtained were 6.40 (4.27-9.61) for embolic stroke followed by 5.99 (5.62-6.38) for atrial fibrillation. The frequency of all CVDs evaluated in patients with a diagnosis of hyperthyroidism was significantly higher in both women and men, as well as in those younger and older than 65 years, compared to subjects without this diagnosis. A multivariate regression analysis showed that hyperthyroidism was significantly and independently associated with all the CVDs evaluated except for embolic stroke.

CONCLUSION

The data from this hospital cohort suggest that there is a significant association between the diagnosis of hyperthyroidism and the main CVRFs and CVDs in our population, regardless of the age and gender of the patients. Our study, in addition to confirming this association, provides useful information for understanding the applicability of artificial intelligence techniques to "real-world data and information".

Hyperthyroidism and cardiovascular risk factors: A nationwide study

BACKGROUND

Thyroid hormones (THs) have important effects on cardiovascular (CV) physiology. Thyroid disorders are accompanied by serious effects on the CV system.

OBJECTIVE

To study the association between hyperthyroidism and the main CV risk factors (CVRFs), such as hypertension, dyslipidemia, diabetes and smoking in the Spanish population.

MATERIAL AND METHODS

An observational, retrospective, non-interventional study was performed using the statistical portal of the Spanish Ministry of Health associated with the Base de Datos Clínicos de Atención Primaria (BDCA) database.

RESULTS

In 2019, 384,182 people [300,243 women (78.1%)] were diagnosed with hyperthyroidism, which represents 1.0% of the population with health problems registered in the BDCAP database (38,365,258 people). The prevalence of hyperthyroidism was more frequent in women (2.48 times) than in men and increased with age. When the whole population was considered, the prevalence of hypertension (34.90% vs. 19.90%; odds ratio, OR 2.16, 95% CI 2.14-2.17), dyslipidemia (34.47% vs. 21.57%; OR 1.90, 95% CI 1.88-1.91), diabetes (12.88% vs. 8.12%; OR 1.66, 95% CI 1.65-1.68) and smoking (10.89% vs. 7.61%; OR 1.48, 95% CI 1.46-1.49) was significantly (p<0.0001) higher in the population diagnosed with hyperthyroidism compared to those without this diagnosis. These significant differences were maintained in both women and men. A separate analysis of the age group 65 years or older showed statistically significant (p<0.0001) differences in the prevalence of hypertension (66.26% vs. 59.43%; OR 1.34, 95% CI 1.33-1.36), dyslipidemia (52.61% vs. 49.05%; OR 1.15, 95% CI 1.14-1.17) and smoking (6.29% vs. 5.93%; OR 1.06, 95% CI 1.04-1.09) between patients with and without a diagnosis of hyperthyroidism, but not in the prevalence of diabetes, which was similar (24.63% vs. 24.63%; OR 1.00, 95% CI 0.99-1.01; p=0.89).

CONCLUSION

Our study shows that the diagnosis of hyperthyroidism is significantly associated with the main CVRFs in Spanish population attended by primary care regardless of the gender of the patients. This association disappears in those patients aged 65 years or older diagnosed with diabetes.

The association of diabetes, subclinical hypothyroidism and carotid intima-media thickness: results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brazil)

INTRODUCTION

The association of diabetes with subclinical thyroid diseases may increase the risk of cardiovascular diseases. We analyzed the association of subclinical hypothyroidism, diabetes, and both diseases with carotid Intima-Media Thickness (cIMT) as a surrogate maker for early cardiovascular disease in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

METHODS

Cross-sectional analysis with data from the 3^rd visit (2017‒2019). Linear regression models were used to evaluate the association of subclinical hypothyroidism, diabetes and of both diseases with a cIMT presented as Beta (95% Confidence Interval ‒ 95% CI) without adjustment, with adjustment for sociodemographic variables (Model 1) and multivariable adjustment (Model 1 more cardiovascular risk factors). We also used logistic regression models to analyze the Odds Ratio (OR) and 95% CI for the association of both diseases using cIMT > P75%.

RESULTS

After the exclusion of patients with previous cardiovascular disease, 5,077 participants with no diseases, 1578 with diabetes, 662 with subclinical hypothyroidism, and 234 with both diseases were included in the analysis. Linear regression models showed an association of cIMT with only diabetes (β = 0.019; 95% CI 0.012 to 0.027; p < 0.0001) and subclinical hypothyroidism more diabetes (β = 0.03; 95% CI 0.010‒0.047, p < 0.0001). The logistic regression model reported an association between diabetes and CIMT higher than P75% (OR = 1.49, 95% CI 1.30‒1.71). No interaction between diabetes and subclinical hypothyroidism was detected using cIMT respectively as a continuous (p = 0.29) or as a categorical variable (p = 0.92).

DISCUSSION

Diabetes was associated with higher cIMT values. However, no additive effect of subclinical hypothyroidism associated with diabetes over cIMT was detected.

Metformin Attenuates Inflammation and Fibrosis in Thyroid-Associated Ophthalmopathy

The pathogenesis of thyroid-associated ophthalmopathy (TAO) is still unclear, and therapeutic drugs have great limitations. As metformin has multiple therapeutic effects in many autoimmune diseases, we explored the effects of metformin on TAO in an in vitro fibroblast model. We used orbital connective tissues and fibroblasts that were obtained from TAO patients and normal controls. The activity of adenosine monophosphate-activated protein kinase (AMPK) and the levels of inflammatory or fibrotic factors were examined by immunofluorescence (IF) and immunohistochemistry (IHC). Quantitative real-time polymerase chain reaction (qPCR), cytokine quantification by enzyme-linked immunosorbent sssay (ELISA), IF, and western blotting (WB) were used to measure the expression of factors related to inflammation, fibrosis, and autophagy. To determine the anti-inflammatory and antifibrotic mechanisms of metformin, we pretreated cells with metformin, 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR, an AMPK activator) or compound C (CC, an AMPK inhibitor) for 24 h and used WB to verify the changes in protein levels in the AMPK/mammalian target of rapamycin (mTOR) pathway. We determined that the low activity of AMPK in the periorbital tissue of TAO patients may be closely related to the occurrence and development of inflammation and fibrosis, and metformin exerts multiple effects by activating AMPK in TAO. Furthermore, we suggest that AMPK may be a potential target of TAO therapy.

Prevalencia de diabetes en personas con disfunción tiroidea

OBJECTIVE

To describe the prevalence and relative risk of diabetes in the population with hypothyroidism and hyperthyroidism.

METHODS

A 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.

RESULTS

In 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.

CONCLUSION

People 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.

Serum Antithyroglobulin Antibody Levels Are Associated with Diabetic Retinopathy among Euthyroid Type 2 Diabetes Patients: A Hospital-Based, Retrospective Study

BACKGROUND

Previous studies have revealed that the variation of thyroid indicators may be associated with the risk of diabetic retinopathy (DR) among euthyroid type 2 diabetes (T2D) patients. But the specific conclusions are currently inconsistent.

METHODS

This is a hospital-based retrospective survey. We recruited 1,145 euthyroid T2D patients and checked the thyroid function and fundus photographs. The modified Airlie House classification system was used to categorize the stages of DR. The association between thyroid indicators and different stages of DR was analyzed.

RESULTS

We divided free triiodothyronine (FT3) into tertiles and found that the prevalence of mild nonproliferative DR (NPDR) was significantly higher in T2, compared with T1 (32.0% vs. 25.2%, p < 0.05). When FT3 was within the level of T2, FT3 could be an independent risk factor for mild NPDR (OR 1.426, 95% CI (1.031, 1.971), p < 0.05). In addition, the prevalence of severe NPDR and proliferative DR (PDR) was significantly higher in thyroglobulin antibody (TgAb) positive group (8.8% vs. 4.1%, p < 0.05) and vice versa (33.3% vs. 18.4%, p < 0.05). TgAb positivity was also an independent risk factor for severe NPDR and PDR (OR 2.212, 95% CI (1.244, 3.934), p < 0.05).

CONCLUSIONS

We hardly observed a significant change in DR risk with the elevation or reduction of serum TSH or thyroid hormone within the reference interval. Although the slightly elevated FT3 may be associated to mild NPDR, the extensibility of this result remains to be seen. For T2D patients with euthyroid function, there may be a significant correlation between serum TgAb positivity and severe NPDR and PDR.

Human immunodeficiency virus, diabetes mellitus and thyroid abnormalities: Should we be screening?

BACKGROUND

Diabetes mellitus (DM) and human immunodeficiency virus (HIV) are associated with thyroid abnormalities. Scarce literature exists on the prevalence of thyroid abnormalities in people living with HIV (PLWH) and DM (PLWHD). Guidelines vary regarding thyroid-stimulating hormone (TSH) screening in PLWH and/or DM.

OBJECTIVES

This study describes thyroid abnormalities in PLWHD and HIV-uninfected people living with DM (PLWD).

METHOD

This was a cross-sectional analysis of demographic, clinical and biochemical data including TSH results of first-visit patients to the Edendale Hospital diabetes clinic between January 2016 and December 2017.

RESULTS

A total of 915 patients were enrolled: 165 PLWHD and 750 PLWD. Overall prevalence of thyroid disorders in PLWD was 8.53% (64/750). The occurrence of 'total' thyroid disorders and of 'subclinical-hypothyroidism' (SCH) was higher in PLWHD than PLWD (23.03% vs. 8.53% and 20.61% vs. 4%, p < 0.001; respectively). People living with HIV and diabetes with thyroid disorders had lower CD4 counts than PLWHD without thyroid disorders (376.08 ± 333.30 vs. 509 ± 341.7 cells/mm3; p = 0.004). Subclinical-hypothyroidism was more common in patients on antiretroviral therapy [ART] (27/136 [19.85%] vs. 4/27 [14.81%], p < 0.001). A significant number of PLWHD acquired HIV before the onset of DM (107/165 [64.85%] vs. 58/165 [35.15%], p < 0.001). Patients on ART were more likely to develop DM, OR 2.66 (95% CI 1.11-6.38).

CONCLUSION

Our study showed an increased prevalence of thyroid disorders (especially SCH) in PLWD and a higher prevalence in PLWHD. Young, overweight, female PLWHD were at risk of SCH. People living with HIV and DM on ART demonstrated an increased prevalence of thyroid dysfunction and poor lipaemic control. The introduction of combined communicable-non-communicable disease clinics might provide an integrated patient screening option.

Thyroid Hormone Changes in Euthyroid Patients with Diabetes

BACKGROUND

Thyroid dysfunction is associated with diabetes, but it is unclear if the thyroid hormone levels change in euthyroid adults with diabetes.

OBJECTIVE

To investigate the association between thyroid hormone levels and diabetes in euthyroid adults.

METHODS

Among the euthyroid adults who underwent health examination in West China Hospital of Sichuan University in 2016, patients with diabetes were identified according to the medical history, fasting blood glucose and HbA1c. Age and sex matched controls were identified from the population. The patients with diabetes group was further divided into two subgroups: patients with newly diagnosed diabetes (NDD) and with previously diagnosed diabetes (PDD). Independent t-test and multivariate logistic regression models were used to investigate the difference in the levels of thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) and the ratio of FT4/FT3 between groups.

RESULTS

We included 32,557 participants, 2,271 with diabetes. Compared to the adults without diabetes, the odds ratios (ORs) per one unit elevation of TSH, FT4, FT4/FT3 ratio and FT3 in patients with diabetes were 0.88 [95% confidence interval (CI): 0.82-0.95], 1.11 (95% CI: 1.08-1.14), 2.05 (95% CI: 1.81-2.32) and 0.85 (95% CI: 0.78-0.93), respectively. Compared to the NDD group, the ORs per one unit elevation of TSH, FT4, FT4/FT3 ratio and FT3 of the PDD group were 0.81 (95% CI: 0.71-0.92), 1.08 (95% CI: 1.04-1.12), 1.76 (95% CI: 1.49-2.08) and 1.01 (95% CI: 0.92-1.12), respectively.

CONCLUSION

In euthyroid adults, diabetes was associated with increased FT4/FT3 ratio, which is linked to the peripheral turnover of the thyroid hormones.

Thyroid Dysfunction and Diabetes Mellitus: Two Closely Associated Disorders

Thyroid dysfunction and diabetes mellitus are closely linked. Several studies have documented the increased prevalence of thyroid disorders in patients with diabetes mellitus and vice versa. This review critically discusses the different underlying mechanisms linking type 1 and 2 diabetes and thyroid dysfunction to demonstrate that the association of these two common disorders is unlikely a simple coincidence. We assess the current state of knowledge on the central and peripheral control of thyroid hormone on food intake and glucose and lipid metabolism in target tissues (such as liver, white and brown adipose tissue, pancreatic β cells, and skeletal muscle) to explain the mechanism linking overt and subclinical hypothyroidism to type 2 diabetes and metabolic syndrome. We also elucidate the common susceptibility genes and the pathogenetic mechanisms contributing to the autoimmune mechanism involved in the onset of type 1 diabetes mellitus and autoimmune thyroid disorders. An untreated thyroid dysfunction can impair the metabolic control of diabetic patients, and this association can have important repercussions on the outcome of both of these disorders. Therefore, we offer recommendations for the diagnosis, management, and screening of thyroid disorders in patients with diabetes mellitus, including the treatment of diabetic patients planning a pregnancy. We also discuss the major causes of failure to achieve an optimal management of thyroid dysfunction in diabetic patients and provide recommendations for assessing and treating these disorders during therapy with antidiabetic drugs. An algorithm for a correct approach of these disorders when linked is also provided.

Effects of Maternal Flaxseed Supplementation on Female Offspring of Diabetic Rats in Serum Concentration of Glucose, Insulin, and Thyroid Hormones

Objective: This study aimed to evaluate the effect of maternal consumption of flaxseed flour and oil on serum concentrations of glucose, insulin, and thyroid hormones of the adult female offspring of diabetic rats. Methods: Wistar rats were induced to diabetes by a high-fat diet (60%) and streptozotocin (35 mg/kg). Rats were mated and once pregnancy was confirmed, were divided into the following groups: Control Group (CG): casein-based diet; High-fat Group (HG): high-fat diet (49%); High-fat Flaxseed Group (HFG): high-fat diet supplemented with 25% flaxseed flour; High-fat Flaxseed Oil group (HOG): high-fat diet, where soya oil was replaced with flaxseed oil. After weaning, female pups (n = 6) from each group were separated, received a commercial rat diet and were sacrificed after 180 days. Serum insulin concentrations were determined by ELISA, the levels of triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) were determined by chemiluminescence. Results: There was a significant reduction in body weight at weaning in HG (-31%), HFG (-33%) and HOG (44%) compared to CG (p = 0.002), which became similar by the end of 180 days. Blood glucose levels were reduced in HFG (-10%, p = 0.044) when compared to CG, and there was no significant difference between groups in relation to insulin, T3, T4, and TSH after 180 days. Conclusions: Maternal severe hyperglycemia during pregnancy and lactation resulted in a microsomal offspring. Maternal consumption of flaxseed reduces blood glucose levels in adult offspring without significant effects on insulin levels and thyroid hormones.

Thyroid dysfunction in patients with impaired glucose metabolism: 11 year follow up from the Tehran Thyroid Study

Objectives

This study aimed to assess the prevalence and incidence and predictive factors of thyroid disorders (TD) in patients with impaired glucose metabolism.

Methods

Prevalence of TD was calculated in patients with impaired glucose metabolism compared to healthy controls, aged over 30 years in phase 1 of the Tehran Thyroid Study (TTS). Follow up assessments were conducted every 3 yrs, after which incidence of TD was calculated and its correlations with age, sex, smoking, blood pressure, body mass index (BMI), thyroid peroxidase antibody (TPOAb), thyrotropin (TSH), insulin resistance index, triglycerides and cholesterol were assessed.

Results

Incidence of TD among 435 diabetics, 286 prediabetics, and 989 healthy controls at baseline was 14, 18, and 21 per 1000 patients per year, respectively, being significantly lower in diabetics than that in healthy controls, a difference however that was not significant after adjusting for the variables mentioned (OR:0.64, 95% CI: 0.39–1.01). The incidence of TD in subjects with baseline serum TSH>1.94 mU/L or TPOAb≥40 IU/ml in all three groups was higher than that in patients with TSH≤1.94 mU/L or TPOAb<40 IU/ml, and remained significant after variable adjustment. Baseline TSH>1.94 mU/L was predictive of TD with 70% sensitivity and specificity. Baseline serum TSH (ROC area: 0.73, 95% CI: 0.68–0.77) had better predictive value than TPOAb (ROC area: 0.65, 95% CI: 0.61–0.69) for developing TD.

Conclusion

Incidence of TD in type 2 diabetics or prediabetics is not higher than healthy controls. It is however necessary to conduct thyroid tests in patients with TPOAb≥40 IU/ml or TSH>1.94 mU/L.

Relation of thyroid hormone abnormalities with subclinical inflammatory activity in patients with type 1 and type 2 diabetes mellitus

Thyroid hormone (TH) abnormalities are common in patients with diabetes mellitus (DM). These thyroid hormone abnormalities have been associated with inflammatory activity in several conditions but this link remains unclear in DM. We assessed the influence of subclinical inflammation in TH metabolism in euthyroid diabetic patients. Cross-sectional study involving 258 subjects divided in 4 groups: 70 patients with T2DM and 55 patients with T1DM and two control groups of 70 and 63 non-diabetic individuals, respectively. Groups were paired by age, sex, and body mass index (BMI). We evaluated the association between clinical and hormonal variables [thyrotropin, reverse T3 (rT3), total and free thyroxine (T4), and triiodothyronine (T3)] with the inflammation markers C-reactive protein (hs-CRP), serum amyloid A (SAA), and interleukin-6 (IL-6). Serum T3 and free T3 were lower in patients with diabetes (all P < 0.001) compared to the control groups. Interleukin-6 showed positive correlations with rT3 in both groups (P < 0.05). IL-6 was independently associated to FT3/rT3 (B = -0.193; 95% CI -0.31; -0.076; P = 0.002) and FT4/rT3 (B = -0.107; 95% CI -0.207; -0.006; P = 0.039) in the T1DM group. In the T2DM group, SAA (B = 0.18; 95% CI 0.089; 0.271; P < 0.001) and hs-CRP (B = -0.069; 95% CI -0.132; -0.007; P = 0.03) predicted FT3 levels. SAA (B = -0.16; 95% CI -0.26; -0.061; P = 0.002) and IL6 (B = 0.123; 95% CI 0.005; 0.241; P = 0.041) were related to FT4/FT3. In DM, differences in TH levels compared to non-diabetic individuals were related to increased subclinical inflammatory activity and BMI. Altered deiodinase activity was probably involved. These findings were independent of sex, age, BMI, and HbA1c levels.

Italian Association of Clinical Endocrinologists (AME) & Italian Association of Clinical Diabetologists (AMD) Position Statement : Diabetes mellitus and thyroid disorders: recommendations for clinical practice

Thyroid disease and diabetes mellitus, the most common disorders in endocrine practice, are not infrequently associated in the same subject. An altered thyroid function may affect glucose tolerance and worsen metabolic control in patients with diabetes. Thyrotoxicosis increases the risk of hyperglycemic emergencies, while a clinically relevant hypothyroidism may have a detrimental effect on glycemic control in diabetic patients. The association of alterations in thyroid function with diabetes mellitus may adversely affect the risk of cardiovascular and microvascular complications resulting from diabetes. Moreover, the treatments used for both diabetes and thyroid disease, respectively, can impact one other. Finally, multinodular goiter, but not thyroid carcinoma, was shown to be more prevalent in type 2 diabetes mellitus. Aim of the present Position Statement is to focus on the evidence concerning the association of thyroid disease and diabetes mellitus and to provide some practical suggestions for an updated clinical management.

Serum cholesterol and triglyceride concentrations in diabetic patients with subclinical hypothyroidism

OBJECTIVE

To assess whether subclinical hypothyroidism is associated to elevations in serum cholesterol and triglyceride levels in patients with type 2 diabetes.

PATIENTS AND METHODS

From a total population of 1,112 patients with type 2 diabetes screened for thyroid dysfunction (thyrotropin measurement), a group of 325 patients with normal thyroid function and another group of 29 patients with subclinical hypothyroidism were selected. No patient had known dyslipidemia or was taking lipid lowering medication.

RESULTS

Patients with subclinical hypothyroidism had serum levels of total cholesterol (4.88 ± 0.74 mmol/L), HDL cholesterol (1.37 ± 0.34 mmol/L), LDL cholesterol (2.94 ± 0.58 mmol/L), and triglycerides (1.05 [0.88-1.41] mmol/L) that did not significantly differ from those found in euthyroid patients (4.79 ± 0.83, 1.33 ± 0.36, 2.87 ± 0.76, and 1.11 [0.81-1.43] mmol/L, respectively). Multiple regression analysis showed no association between TSH and serum lipid levels.

CONCLUSION

These results suggest that, in our population, there are no significant differences in serum cholesterol and triglyceride levels between diabetic patients with normal and reduced thyroid function.

Non-alcoholic fatty liver disease and thyroid dysfunction: A systematic review

Thyroid hormones are totally involved in the regulation of body weight, lipid metabolism, and insulin resistance. Therefore it is anticipated that thyroid hormones may have a role in the pathogenesis of non alcoholic fatty liver disease (NAFLD) and non alcoholic steatohepatitis (NASH). In this study, we reviewed the current literature on the association between thyroid dysfunction and NAFLD/NASH. A search for English language medical literature reporting an association between thyroid dysfunction and NAFLD/NASH in humans was conducted across PubMed, ISI Web of Science, and Scopus in August, 2013. Out of 140 studies initially identified through the search, 11 relevant articles were included in the final review. Thyroid dysfunctions in the form of overt or subclinical hypothyroidism are prevalent among patients with NAFLD/NASH. Hypothyroidism appears to be an independent risk factor for NAFLD/NASH in some studies; however, other newly published studies failed to find such an association. The results of the studies on the role of thyroid abnormalities in NAFLD/NASH are inconsistent, and further research is recommended to determine the relationship between hypothyroidism and NAFLD/NASH and the underlying mechanisms.

Thyroid disease in insulin-treated patients with type 2 diabetes: a retrospective study

BACKGROUND

Diabetes mellitus and thyroid diseases frequently coexist. In order to evaluate how thyroid disorders interfere with glycemic control, we analysed insulin-treated type 2 diabetes patients with thyroid disease.

METHODS

Diabetes patients (n = 1.957) were retrospectively investigated. We focused on type 2 diabetes patients who had been admitted for insulin-treatment and diagnosed thyroid diseases (n = 328). Patients were divided into three groups according to thyroid disease manifestation in relation to diabetes onset: prior to (group 1), same year (group 2) and thyroid disease following diabetes (group 3).

RESULTS

Out of all diabetes patients 27.3% had a thyroid disorder with more women (62.2%) being affected (p < 0.001). Thyroid disease was predominantly diagnosed after diabetes onset. Patients with type 2 diabetes and prior appearance of thyroid disease required insulin therapy significantly earlier (median insulin-free period: 2.5 yrs; Q1 = 0.0, Q3 = 8.25) compared to patients who had thyroid dysfunction after diabetes onset (median insulin-free period: 8.0 yrs; Q1 = 3.0, Q3 = 12.0; p < 0.001). Age at diabetes onset correlated with insulin-free period (p < 0.001).

CONCLUSIONS

Thyroid disease may be a marker of a distinct metabolic trait in type 2 diabetes potentially requiring earlier insulin treatment.

Relationship between serum thyrotropin concentrations and metformin therapy in euthyroid patients with type 2 diabetes

AIM

A thyrotropin(TSH)-lowering effect of metformin therapy has been recently reported in patients with type 2 diabetes (T2D) and hypothyroidism. We aimed to evaluate the interplay between metformin therapy and serum TSH concentrations in a group of patients with T2D and normal thyroid function.

PATIENTS AND METHODS

Eight hundred and twenty-eight euthyroid patients with T2D (53% women, mean age 65·9 years, median duration of diabetes 10 years) were retrospectively evaluated. There were 250 patients on metformin treatment (30·2%). Serum concentrations of TSH were measured in all subjects.

RESULTS

Patients on metformin treatment exhibited significantly higher TSH levels [1·63 (1·11-2·24) mU/l] than those found in patients without metformin [1·40 (1·01-2·24) mU/l, P = 0·009]. We found no significant differences in TSH levels in patients who were on therapy with other oral antidiabetics, antihypertensive drugs or hypolipidemic agents in relation to subjects not taking these drugs. Serum TSH was significantly related to gender, body mass index, hyperlipidaemia and the presence of goitre and diabetic macroangiopathy. In multiple regression analysis with TSH as dependent variable, goitre was negatively related to TSH values. Metformin therapy was a nonsignificant variable in this model.

CONCLUSION

In summary, this is the first survey analysing the relationship between metformin and thyroid function in a large cohort of patients with diabetes. Our data do not support the presence of an independent and significant relationship between TSH values and metformin treatment in euthyroid patients with T2D.

Thyroid function and stress hormones in children with stress hyperglycemia

The purpose of the study is to determine the prevalence of stress hyperglycemia and to investigate how thyroid and stress hormones alter during stress hyperglycemia in children admitted to pediatric emergency wards. A prospective cross-sectional study was conducted in children, less than 19 years old, who were admitted to pediatric emergency wards of Nemazee and Dastgheib Hospitals, Shiraz, Southern Iran. Those patients taking steroids, beta-agonists or intravenously administered glucose before venipuncture, and patients with diabetes mellitus (DM) or thyroid diseases were excluded. Children with blood glucose ≥ 150 mg/dL during admission were regarded as cases. The controls were age- and- sex- matched, euglycemic children. Stress hormones including cortisol, insulin, growth hormone, and prolactin were measured, and thyroid function was tested with a radioimmunoassay (RIA) method in all cases and controls. The results showed that among 1,054 screened children, 39 cases (3.7 %) had stress hyperglycemia and 89 controls were included in the study. The occurrence of hyperglycemia was independent of sex, but it occurred mostly in children under 6 years old. Hyperglycemia occurred more frequently in patients with a positive family history of DM (odds ratio = 3.2, 95 % CI = 1.3-7.9, and P = 0.009). There were no significant differences between cases and controls regarding any hormones except higher cortisol, and lower total T3 and T4 in cases compared with controls. Neither of cases developed diabetes in the 24-month follow-up period. These findings led us to the conclusion that stress hyperglycemia is occasionally seen in critically ill patients. Among the stress hormones measured, only cortisol increased during hyperglycemia. It seems that hyperglycemia is not an important risk factor for future diabetes.

Type 2 diabetes mellitus and risk of incident atrial fibrillation in women

OBJECTIVES

The purpose of this study was to assess whether changes of major atrial fibrillation (AF) risk factors and/or intercurrent cardiovascular events could explain the relationship between type 2 diabetes mellitus (T2D) and incident AF.

BACKGROUND

Previous studies found an increased risk of incident AF among individuals with T2D, but few, if any, of these studies took into account changes of AF risk factors over time.

METHODS

A total of 34,720 female health professionals who participated in the Women's Health Study, and who were free of cardiovascular disease and AF at baseline were followed for a median of 16.4 years. Cox proportional-hazards models were constructed to assess the relationship between T2D and incident AF, using either information at baseline or time-varying covariates for both T2D and potential confounders.

RESULTS

At baseline, 937 (2.7 %) women had T2D. Compared with women without T2D, women with T2D had an age-adjusted hazard ratio (HR) for new-onset AF of 1.95 (95% confidence interval [CI]: 1.49 to 2.56; p<0.0001). In multivariable analyses adjusting for baseline confounders, this HR was substantially attenuated, but baseline T2D remained a significant predictor of incident AF (HR: 1.37, 95% CI: 1.03 to 1.83; p=0.03). In time-updated models that adjusted for changes in AF risk factors and intercurrent cardiovascular events, the HR for T2D was attenuated further and became nonsignificant (HR: 1.14; 95% CI: 0.93 to 1.40; p=0.20).

CONCLUSIONS

Although this study confirms a significant relationship between baseline T2D and incident AF, our data suggest that the increased risk associated with T2D is mainly mediated by changes of other AF risk factors.