Other complications and associated conditions with diabetes in children and adolescents

The interface between thyroid and diabetes mellitus

Thyroid disease and type 1 but also type 2 diabetes mellitus (DM) are strongly associated, and this has important clinical implications for insulin sensitivity and treatment requirements. The pathophysiological basis of this association has only recently been better elucidated. It rests on a complex interaction of common signalling pathways and, in the case of type 1 diabetes and autoimmune thyroid disease, on a linked genetic susceptibility. The pathophysiological mechanisms underlying this linked regulation are increasingly being unravelled. They are exemplified in the regulation of 5' adenosine monophosphate-activated protein kinase (AMPK), a central target not only for the modulation of insulin sensitivity but also for the feedback of thyroid hormones on appetite and energy expenditure. The present review will discuss these concepts and their consequences for the clinical care of patients with DM and thyroid disorders. Moreover, it makes reference to the added effect of metformin in suppressing TSH.

Do children and adolescents with type 1 diabetes mellitus have a higher frequency of parietal cell antibodies than healthy controls?

OBJECTIVES

Parietal cell antibodies (PCA) are markers of autoimmune gastritis (AG). AG can lead to hypergastrinemia and iron-deficiency anaemia (IDA). Compared to healthy controls, adults with type 1 diabetes mellitus (T1DM) show a higher prevalence of PCA (1% vs 20%). The aim of the present study was to evaluate the frequency of PCA in children and adolescents with T1DM compared to healthy controls and the clinical and biochemical markers.

PATIENTS AND METHODS

We studied 170 patients (87 boys) with T1DM (mean age 12.9 years) and 101 healthy controls (49 boys; mean age 13.0 years). PCA, free T4, free T3, thyroid-stimulating hormone (TSH), and thyroid antibodies were measured in all of the patients. In addition, gastrin, pepsinogen I, iron, ferritin, vitamin B12, and folate were measured in patients with T1DM only. Gastroscopy was carried out in patients with T1DM having high (>100 U/mL) PCA levels.

RESULTS

The frequency of PCA in patients with T1DM was 5.29% compared to 1.98% in healthy controls (not significant). PCA was strongly correlated to both thyroid peroxidase antibodies (TPOAb) and gastrin levels (P = 0.001). IDA was present in 4 of 9 patients from the PCA-positive group compared to 4 of 160 patients from the PCA-negative group. Hypergastrinemia was found in 2 PCA-positive patients. Histopathologically, 1 of 4 patients showed early symptoms of AG.

CONCLUSIONS

Children and adolescents with T1DM have a lower frequency of PCA than is reported for adults. Compared to healthy controls, they seem to be at increased risk for developing PCA, in particular if positive for TPOAb, but overt clinical disease is rare in children with T1DM.

Potential celiac disease in type 1 diabetes: a multicenter study

AIMS

To describe the prevalence of potential celiac disease (pot-CD) in young patients with type 1 diabetes mellitus (T1DM) and characterize their clinical features.

METHODS

This cross-sectional multicenter study involved 8717 T1DM patients from 31 Italian centers. Information was collected on the total number of T1DM patients, CD patients and pot-CD patients. The following data were collected on pot-CD patients: gender, age at T1DM diagnosis, age at the first CD serological positivity, presence of CD-related symptoms, presence of other autoimmune disorders and treatment with gluten free diet (GFD). One thousand-three-hundred-sixty-one patients who were positive for CD serology were the control group.

RESULTS

CD serological positivity was found in 7.2% T1DM patients. Prevalence of pot-CD was 12.2% (n=77) among CD positive patients: symptoms were present in 12/77; a third autoimmune disorder was found in 15 patients. Prevalence of pot-CD in the control population was 8.4% (n=114; p=0.005). No difference was found with regard to clinical features. Only few symptomatic patients were on GFD both in T1DM and control patients.

CONCLUSIONS

A higher prevalence of pot-CD was found in T1DM patients, that may be ascribed to the routine screening, although the influence of genetic factors cannot be excluded.

Anthropometry, metabolic control, and follow-up in children and adolescents with type 1 diabetes mellitus and biopsy-proven celiac disease

OBJECTIVE

To evaluate the influence of biopsy-proven celiac disease (BPCD) on somatic development and metabolic parameters in children with type 1 diabetes mellitus (T1DM) in a multicenter survey.

STUDY DESIGN

Within the Diabetes Patienten Verlaufsdokumentationssystem-Wiss project, data of 41 951 patients with T1DM, aged <20 years (52% males, mean age 13.9 years; mean duration of diabetes 5.5 years) were collected in 297 centers in Germany and Austria from 1995 to 2009.

RESULTS

The number of BPCD (0.6% in 1995; 1.3% in 2008) has increased over time. Patients with BPCD were significantly younger at diabetes onset (5.9 vs 8.3 years), had a significantly lower weight standard deviation score (SDS); (0.20 vs 0.43) and height SDS (-0.28 vs -0.03) (P < .001, each) compared with patients without celiac disease. No differences were found in hemoglobin A1c or numbers of severe hypoglycemia. In a subgroup of 9805 patients (183 with BPCD) significantly lower height and weight SDS (P < .001) were still found after a 5-year follow-up.

CONCLUSIONS

Screening for celiac disease is important in children with T1DM to prevent persistent growth failure.

GADA positivity at onset of type 1 diabetes is a risk factor for the development of autoimmune thyroiditis

AIM

To evaluate whether the presence of diabetes-specific autoantibodies may predict the development of autoimmune thyroiditis (AIT) in children with type 1 diabetes (T1D).

METHODS

Glutamic acid decarboxylase antibodies (GADA), tyrosine phosphatase IA2 antibodies (IA2A), and insulin autoantibodies (IAA) were determined at T1D onset in 341 children and adolescents. Thyroid antibodies (anti-TG, anti-TPO), thyroid stimulating hormone (TSH), T(3) and T(4) were measured in 335 patients at T1D onset and thereafter annually with a follow-up time of 1-15 yr. In case of thyroid antibody positivity and/or TSH elevation, thyroid gland sonography was performed. Treatment with l-thyroxine was started if persistent elevation of TSH and/or thyroid volume was present.

RESULTS

The majority of patients (92.1%) had at least one T1D antibody (71.6% GADA, 73.0% IA2A, and 44.9% IAA). GADA positive patients were older than those without GADA (p < 0.001). Thyroid autoimmunity was found in 15 of 335 patients (4.5%) at T1D onset with female preponderance (p = 0.013). At the end of follow-up, 70 patients (20.9%) had developed thyroid autoantibodies [cumulative incidence (CI) 0.36 ± 0.06 at 10 yr of T1D]. In 30 patients (9.0%), AIT was diagnosed up to 9.4 yr after T1D onset (CI 0.24 ± 0.06 at 10 yr). AIT incidence was not influenced by IAA or IA2A positivity. In multivariate analysis, GADA positive patients were estimated to have a 3.5-fold increased risk of AIT (CI 0.31 ± 0.11 at 10 yr) compared to those without GADA (p = 0.024).

CONCLUSION

Based on the present results, a special focus should be given to GADA positive patients concerning screening for AIT as they are at increased risk to develop autoimmune thyroiditis.

Diabetes and thyroid disorders

It has long been recognised that thyroid hormones have marked effects on glucose homeostasis. Glucose intolerance is associated with hyperthyroidism and most recently it was shown that hypothyroidism is characterised by insulin resistance. Although autoimmune thyroid disease is more prevalent in type 1 diabetes as a result of their common origin, in patients with type 2 diabetes the prevalence of hypothyroidism and hyperthyroidism is similar to that of the general population. However, in type 2 diabetic patients, the presence of the highly frequent sub-clinical forms of hyperthyroidism and hypothyroidism should be ruled out since they may be associated with higher cardiovascular risk. While there are no doubts about the therapeutic impact of normalising hypothyroidism and hyperthyroidism, the information available about the benefit of treating subclinical thyroid disease in diabetes remains insufficient.

Thyroid dysfunction in patients with diabetes: clinical implications and screening strategies

BACKGROUND

Patients with diabetes mellitus are at an increased risk of thyroid disease. The frequency of thyroid dysfunction in diabetic patients is higher than that of the general population and up to a third of patients with type-1 diabetes (T1DM) ultimately develop thyroid dysfunction. Unrecognised thyroid dysfunction may impair metabolic control and add to cardiovascular disease risk in diabetic patients.

AIMS

Our aims were to review the current literature on the association between thyroid dysfunction and diabetes mellitus, to highlight relevant clinical implications, and to examine present thyroid disease screening strategies in routine diabetes care.

RESULTS

The pleiotropic effects of thyroid hormones on various metabolic processes are now better understood. Uncontrolled hyperthyroidism in diabetic patients may trigger hyperglycaemic emergencies while recurrent hypoglycaemic episodes have been reported in diabetic patients with hypothyroidism. Furthermore, thyroid dysfunction may amplify cardiovascular disease risk in diabetic patients through inter-relationships with dyslipidaemia, insulin resistance and vascular endothelial dysfunction. However, the significance of subclinical degrees of thyroid dysfunction remains to be clarified. While these developments have implications for diabetic patients a consensus is yet to be reached on optimal thyroid screening strategies in diabetes management.

CONCLUSIONS

The increased frequency of thyroid dysfunction in diabetic patients and its likely deleterious effects on cardiovascular and metabolic function calls for a systematic approach to thyroid disease screening in diabetes. Routine annual thyroid testing should be targeted at diabetic patients at risk of thyroid dysfunction such as patients with T1DM, positive thyroid autoantibodies or high-normal TSH concentrations.