Hypothyroidism among pediatric patients with type 1 diabetes mellitus, from patients' characteristics to disease severity

Olfactory function in diabetes mellitus

Diabetes mellitus (DM) is an increasingly common disease in both children and adults. In addition to neuronal and/or vascular disorders, it can cause chemosensory abnormalities including olfactory deterioration. The purpose of this article is to summarize current knowledge on olfactory function in DM, highlighting the impact of co-morbidities, especially obesity, thyroid dysfunction, chronic kidney disease and COVID-19 on olfactory outcomes. Research to date mostly shows that olfactory impairment is more common in people with diabetes than in the general population. In addition, the presence of concomitant diseases is a factor increasing olfactory impairment. Such a correlation was shown for type 1 diabetes, type 2 diabetes and gestational diabetes. At the same time, not only chronic diseases, but also DM in acute conditions such as COVID-19 leads to a higher prevalence of olfactory disorders during infection. Analyzing the existing literature, it is important to be aware of the limitations of published studies. These include the small number of patients studied, the lack of uniformity in the methods used to assess the sense of smell, frequently relying on rated olfactory function only, and the simultaneous analysis of patients with different types of diabetes, often without a clear indication of diabetes type. In addition, the number of available publications is small. Certainly, further research in this area is needed. From a practical point of view decreased olfactory performance may be an indicator for central neuropathy and an indication for assessing the patient's nutritional status, examining cognitive function, especially in older patients and performing additional diagnostic tests, such as checking thyroid function, because all those changes were correlated with smell deterioration.

Predictors of the clinical severity of T1DM presentation at diagnosis in children and adolescents with type 1 diabetes mellitus (T1DM)

PURPOSE

We aimed to assess factors associated with the presence and severity of ketoacidosis (DKA) at pediatric type 1 diabetes (T1DM) diagnosis, in relation to pancreatic, associated and familial autoimmunity.

METHODS

Antibodies against pancreatic beta-cells, organ specific autoantibodies (thyroid, celiac, and parietal) and family history of autoimmunity were retrospectively evaluated in 116 T1DM patients aged 11.9 ± 4.6 (mean ± SD) years, with disease duration 7.62 ± 3.67 years (mean ± SD).

RESULTS

Most patients (67.2%) presented with DKA at diagnosis. Younger children (< 2 years) had tenfold risk of DKA, compared to older children (12.1-15 years) (OR = 10.8, 95% CI: 1.0-116.9, P = 0.05). Fasting c-peptide levels were lower in the DKA group (OR = 0.26, 95% CI = 0.07-0.89, P = 0.033). The number of anti-pancreatic antibodies at disease onset did not show any significant correlations with the presence (p = 0.889) or severity of DKA (p = 0.863). All patients with multiple autoimmunity (> 2 autoimmune diseases plus T1DM) presented with DKA. Familial autoimmunity acted protectively against DKA manifestation (OR = 0.40, 95% CI = 0.16-1.0, P = 0.051).

CONCLUSIONS

Among newly diagnosed T1DM patients, 67.2% presented with DKA. Younger age, lower c-peptide and the presence of associated autoimmunity were predictive factors of the presence and severity of DKA at diagnosis. High degree of suspicion, due to family history, may prevent DKA development and severity.

Significance of monitoring the levels of thyroid hormone antibodies and glucose and lipid metabolism antibodies in patients suffer from type 2 diabetes

The association of thyroid hormone antibodies and glycolipid metabolism indicators with Type 2 diabetes mellitus (T2DM) was explored. As the disease worsens, the levels of thyroglobulin antibody (TGAb), thyroid peroxidase antibody (TPOAb), and thyroid-stimulating hormone (TSH) was increased, and the levels of total tri-iodothyronine (TT3) and total thyroxine (TT4) was decreased (P < 0.001). The severe, medium, and light group had higher level of high-density lipoprotein (HDL), lower level of total cholesterol (TC), low-density lipoprotein (LDL), glycosylated hemoglobin (HbA1c), triacylglycerol (TAG), and fasting blood sugar (FBG) than the control group (P ＜ 0.05). The level of HDL was lower in the severe group than the light group and the medium group, but the levels of TC, LDL, HbA1c, TAG, and FBG were increased with the progress of T2DM (P ＜ 0.001). The levels of TGAb, TPOAb, and TSH in patients with T2DM were positively correlated with the levels of TC, LDL, HbA1c, TAG, and FBG (P < 0.05), and were negatively correlated with HDL levels (P < 0.05). The life quality score was lower in the severe group than the light and the medium group (P < 0.001). Among the above indicators, the predictive value of TT3, TT4, and HbA1c in T2DM was better. Clinically, detecting the levels of thyroid hormone antibodies and glycolipid metabolism indicators had a certain predictive value for the severity of T2DM. Main findings: The results of this study found that the thyroid hormone antibody and glycolipid metabolism levels in T2DM patients were abnormal, and had different degrees of impact on the quality of life of patients. Thus, monitoring these indicators had certain predictive value for the severity of the disease, and also had a certain degree of suggestive effect on the evaluation of diabetic vascular complications. Clinically, attention should be paid to the screening of thyroid disease in diabetic patients, and the assessment and prognosis of thyroid function on diabetes, the control of diabetes, and the prevention and treatment of complications have important clinical significance.

Diabetes Modulates Iodothyronine Deiodinase 2 Expression in the Mouse Retina: A Role for Thyroid Hormone in the Pathogenesis of Diabetic Retinopathy

Purpose

Clinical investigations associate hypothyroidism with an increased risk for microvascular complications, yet the mechanism by which thyroid hormone regulates the development of diabetic retinopathy is not clearly understood. We investigated the role of iodothyronine deiodinase 2 (DIO2) in the pathogenesis of diabetic retinopathy.

Methods

Retinas from streptozotocin-induced diabetic and nondiabetic mice were evaluated by RNA sequencing, RT-PCR, and immunostaining. Media and cell lysates from mouse retinal microvascular endothelial cells and retinal astrocytes exposed to physiologic (5 mM) and high glucose (25 mM) containing media were assessed by liquid chromatography-tandem mass spectrometry to measure tetraiodothyronine (T4) and tri-iodothyronine (T3) concentrations and by Western blot analysis to determine the relationship of T4/T3 to oxidative stress and inflammatory mediators. Cell death was determined by Trypan Blue exclusion assay.

Results

At 12 weeks of diabetes duration, retinas from diabetic mice compared with nondiabetic mice demonstrated a significant decrease in Dio2 transcripts and Dio2 gene and protein (P < 0.05) expression. When cultured in the presence of high glucose, both mouse retinal astrocytes and microvascular endothelial cells demonstrated a significant reduction of DIO2 protein compared with cells cultured in physiologic glucose. High glucose inhibited generation of T3, leading to a significantly increased T4/T3 (P < 0.0079). Supplementation of cells with T3, but not T4, prevented the high glucose-induced rise in endothelial nitric oxide synthase, intercellular cell adhesion molecule 1, and endothelial cell death (P < 0.0079).

Conclusions

Decreased intraretinal T3 owing to diabetes-induced loss of DIO2 may lead to dysfunction and death of cells in the retina, thereby contributing to the pathogenesis of early diabetic retinopathy.

Evaluation of the Thyroid Characteristics and Correlated Factors in Hospitalized Patients with Newly Diagnosed Type 2 Diabetes

BACKGROUND

Diabetes mellitus (DM) and thyroid dysfunction (TD) are two closely associated disorders. The objective of the present study was to investigate the thyroid status and the relationships between thyroid hormones, diabetic complications and metabolic parameters in hospitalized patients with newly diagnosed type 2 DM (T2DM).

METHODS

This was an observational cross-sectional study, conducting on 340 patients with newly diagnosed T2DM who were admitted to ward of endocrinology department and 120 matched individuals without diabetes. Anthropometric, clinical and biochemical data were collected. Spearman correlation coefficients were calculated to evaluate the correlations between thyroid hormones and other variables. Factors associated with diabetic nephropathy (DN) was analyzed with multivariate logistic regression.

RESULTS

Levels of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) were significantly lower in patients with T2DM as compared to control group without diabetes. The prevalence of TD was 21.2% in patients with diabetes, higher than that in controls (4.2%). The low T3 syndrome was the most frequent TD, shown in 14.7% of patients. The presence of diabetic complications DN, diabetic ketosis or ketoacidosis), metabolic and demographic factors, including age, glycemic control and insulin resistance were factors significantly associated with levels of thyroid hormones. FT3 level was inversely correlated with the level of urinary total protein (mg/24h) and the presence of DN. Multivariate analysis indicated low FT3 level as a strong independent risk factor (OR = 0.364, P = 0.001) for DN.

CONCLUSION

TD is not rarely seen in hospitalized patients with newly diagnosed T2DM. Diabetic complications and diabetes-related metabolic and demographic factors are related to thyroid hormone levels. Decreased FT3 is strongly correlated with the presence of DN.

Thyroid Dysfunction and Dysmetabolic Syndrome: The Need for Enhanced Thyrovigilance Strategies

Thyroid dysfunction (TD) is common in metabolic disorders such as diabetes mellitus (DM), cardiovascular disease (CVD), obesity, dyslipidemia, hyperuricemia, kidney and liver dysfunctions, and polycystic ovary syndrome (PCOS). Subclinical hypothyroidism (SHypo) worsens glycemic control in patients with DM, and these patients, especially those with Type-1DM, have higher prevalence of TD. Both TD and DM increase CVD risk. Even minor alteration in thyroid hormone (TH) levels can alter cardiovascular function. While hyperthyroidism increases systolic blood pressure and leads to high-output heart failure, hypothyroidism increases diastolic blood pressure and leads to low-output heart failure. Chronic subclinical hyperthyroidism (SHyper) and SHypo both increase the risk of hypertension, coronary artery disease (CAD) events, CAD deaths, and total deaths. SHyper alters cardiac morphology and function. SHypo causes dyslipidemia and endothelial dysfunction and increases the risk for weight gain and obesity. Overweight and obese patients often have hyperleptinemia, which increases the secretion of thyroid stimulating hormone (TSH) and induces TD. Dyslipidemia associated with TD can increase serum uric acid levels. Hyperuricemia promotes inflammation and may increase the risk for dyslipidemia, atherosclerosis, and CVD. TD increases the risk for developing chronic kidney disease. In nephrotic syndrome, proteinuria is associated with urinary loss of TH leading to TD. Some correlation between TD and severity of liver disease is also seen. TD and PCOS have common risk factors and pathophysiological abnormalities. Hypothyroidism must be excluded before diagnosing PCOS. Current guidelines do not strongly recommend thyroid screening in the presence of all metabolic disorders. However, pragmatic thyrovigilance is required. Clinicians must stay alert to signs and symptoms of TD, maintain high clinical suspicion, and investigate thoroughly. Drug-induced TD should be considered when TH levels do not match clinical findings or when patients are on medications that can alter thyroid function.

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.

Factors associated with thyroid dysfunction in children with newly diagnosed type 1 diabetes mellitus

BACKGROUND

This study aimed to investigate the possible factors associated with thyroid dysfunction (TD) in children with type 1 diabetes mellitus (T1DM).

METHODS

Eighty-seven children with T1DM were evaluated in terms of their clinical profile as well as tested for pancreatic and thyroid antibodies. Thyroid function was tested at baseline and 10 days after treatment onset.

RESULTS

Thyroid dysfunction was present in 13 (14.9%) patients after correction of acute metabolic disorders. The prevalence of subclinical hypothyroidism (10.3%) was found to be higher than that of clinical hypothyroidism (3.4%) and clinical hyperthyroidism (1.2%). Both pancreatic and thyroid antibody were detected positive in TD patients, which was significantly different from that with euthyroidism (P<0.01, P<0.05). The frequency of TD family history was significantly higher in subjects with TD rather than with euthyroidism (P<0.01). The levels of free and total triiodothyronine, free and total thyroxine were in the hypothyroid range at the time of admission, all of which increased to normal range after 10 days of therapy in 32 DKA children (P=0.02 and P<0.01). There was a significant correlation between pH and free triiodothyronine levels (P<0.05).

CONCLUSIONS

TD is related to family factors, autoimmunity, and acute metabolic stress in the T1DM and regular thyroid screening should be performed.