Prediabetes blunts DPP4 genetic control of postprandial glycaemia and insulin secretion

AIMS/HYPOTHESIS

Imbalances in glucose metabolism are hallmarks of clinically silent prediabetes (defined as impaired fasting glucose and/or impaired glucose tolerance) representing dysmetabolism trajectories leading to type 2 diabetes. CD26/dipeptidyl peptidase 4 (DPP4) is a clinically proven molecular target of diabetes-controlling drugs but the DPP4 gene control of dysglycaemia is not proven.

METHODS

We dissected the genetic control of post-OGTT and insulin release responses by the DPP4 gene in a Portuguese population-based cohort of mainly European ancestry that comprised individuals with normoglycaemia and prediabetes, and in mouse experimental models of Dpp4 deficiency and hyperenergetic diet.

RESULTS

In individuals with normoglycaemia, DPP4 single-nucleotide variants governed glycaemic excursions (rs4664446, p=1.63x10^-7) and C-peptide release responses (rs2300757, p=6.86x10^-5) upon OGTT. Association with blood glucose levels was stronger at 30 min OGTT, but a higher association with the genetic control of insulin secretion was detected in later phases of the post-OGTT response, suggesting that the DPP4 gene directly senses glucose challenges. Accordingly, in mice fed a normal chow diet but not a high-fat diet, we found that, under OGTT, expression of Dpp4 is strongly downregulated at 30 min in the mouse liver. Strikingly, no genetic association was found in prediabetic individuals, indicating that post-OGTT control by DPP4 is abrogated in prediabetes. Furthermore, Dpp4 KO mice provided concordant evidence that Dpp4 modulates post-OGTT C-peptide release in normoglycaemic but not dysmetabolic states.

CONCLUSIONS/INTERPRETATION

These results showed the DPP4 gene as a strong determinant of post-OGTT levels via glucose-sensing mechanisms that are abrogated in prediabetes. We propose that impairments in DPP4 control of post-OGTT insulin responses are part of molecular mechanisms underlying early metabolic disturbances associated with type 2 diabetes.

Interpersonal Relationships in Diabetes: Views and Experience of People with Diabetes, Informal Carers, and Healthcare Professionals in Portugal

INTRODUCTION

The increasing burden of diabetes poses a great challenge to healthcare systems and economy worldwide. Although modern therapeutic strategies for diabetes are widely available, most patients still fail to achieve optimal clinical targets and well-being. The primary objective of this study was to assess and explore potential drivers and successful management of diabetes among people with diabetes, family members and healthcare professionals in Portugal, by applying the protocol of the multinational study "Diabetes, Attitudes, Wishes and Needs (DAWN2)".

MATERIAL AND METHODS

A total of 767 adults, including 417 people with diabetes, 123 family members and 227 healthcare professionals, participated in the study. Surveys assessed health-related quality of life, self-management, attitudes/beliefs, social support and priorities for improvement areas in diabetes care.

RESULTS

Diabetes has a negative impact on the physical health and emotional well-being of patients in Portugal and is also a psychological burden for family members. Earlier diagnosis and treatment of diabetes were mentioned as a major area of improvement. Healthcare professionals indicated the need for diabetes self-management education.

CONCLUSION

We have used for the first time in Portugal the DAWN2 protocol to address the wishes, needs, and attitudes of Portuguese diabetes patients, their relatives, and healthcare professionals regarding the disease.

Loss of postprandial insulin clearance control by Insulin-degrading enzyme drives dysmetabolism traits

Systemic insulin availability is determined by a balance between beta-cell secretion capacity and insulin clearance (IC). Insulin-degrading enzyme (IDE) is involved in the intracellular mechanisms underlying IC. The liver is a major player in IC control yet the role of hepatic IDE in glucose and lipid homeostasis remains unexplored. We hypothesized that IDE governs postprandial IC and hepatic IDE dysfunction amplifies dysmetabolic responses and prediabetes traits such as hepatic steatosis. In a European/Portuguese population-based cohort, IDE SNPs were strongly associated with postprandial IC in normoglycemic men but to a considerably lesser extent in women or in subjects with prediabetes. Liver-specific knockout-mice (LS-IDE KO) under normal chow diet (NCD), showed reduced postprandial IC with glucose intolerance and under high fat diet (HFD) were more susceptible to hepatic steatosis than control mice. This suggests that regulation of IC by IDE contributes to liver metabolic resilience. In agreement, LS-IDE KO hepatocytes revealed reduction of Glut2 expression levels with consequent impairment of glucose uptake and upregulation of CD36, a major hepatic free fatty acid transporter. Together these findings provide strong evidence that dysfunctional IC due to abnormal IDE regulation directly impairs postprandial hepatic glucose disposal and increases susceptibility to dysmetabolic conditions in the setting of Western diet/lifestyle.

Association between area- and individual-level socio-economic factors with glycated haemoglobin-Evidence from a Portuguese population-based study

AIMS

This study aims to estimate the associations between area-level deprivation and individual-level socio-economic factors, as well as their interaction, with glycated haemoglobin (HbA_1c ) levels.

METHODS

We conducted a gamma multilevel regression analysis using individual-level data from the Portuguese National Health Examination Survey and a deprivation index built through factor analysis, at municipality level, with census variables.

RESULTS

Living in a municipality with high material deprivation and having a low level of education were independently associated with an increase of 2.3% (95% confidence interval [CI] 0.6, 4.0) and of 1.6% (95% CI 0.6, 2.7) in the mean levels of HbA_1c , respectively. The interaction between area material deprivation and individual-level education was not associated with the levels of HbA_1c (0.5%, 95% CI -1.3, 2.3).

CONCLUSIONS

Our findings support the collective resources model that argues that people in less deprived areas have better health because there are more collective resources. The results suggest that to reduce socio-economic inequalities associated with the levels of HbA_1c and, consequently, with diabetes, will require attention to the area material deprivation and individual-level education. Upstream social determinants of health are thus highlighted.

Prevalence, awareness, treatment and control of diabetes in Portugal: Results from the first National Health examination Survey (INSEF 2015)

AIMS

Diabetes Mellitus is a major public health threat worldwide and continues to increase in numbers and significance. Estimates of diabetes prevalence, awareness, treatment and control are essential to effectively monitor its trends, plan and evaluate interventions.

METHODS

We conducted a nationwide health examination survey in the population residing in Portugal aged between 25 and 74 years old in 2015. It consisted in a cross sectional prevalence study which included the measurement of HbA1c, a physical examination and a general health interview of a probabilistic sample of 4911 individuals (Authorization n°9348/2010 of the National Committee for Data Protection).

RESULTS

The overall prevalence of diabetes was 9.9% (95%CI: 8.4; 11.5). It was higher in males than in females (12.1% vs 7.8%). Diabetes was more prevalent among individuals of lower education and without any professional activity. The majority of persons with diabetes was aware of their condition (87.1%) and was taking antidiabetic medication (79.7%). Of these, 63.2% had glycated hemoglobin levels lower than 7.0% (53 mmol/mol), but the majority failed to comply with the LDL and blood pressure recommended clinical targets (71.9% and 59.0%). Similarly, the prevalence of prediabetes was 16%, higher among women than men (17.5% vs 14.4%).

CONCLUSION

The prevalence of diabetes and prediabetes remains higher than the global and European estimates, although there is increasing awareness of this disorder.

Trends in diabetes incidence from 1992 to 2015 and projections for 2024: A Portuguese General Practitioner's Network study

BACKGROUND

Diabetes is known as a major cause of morbidity and mortality worldwide. Portugal is known as the European country with the highest prevalence of this disease. While diabetes prevalence data is updated annually in Portugal, the General Practitioner's (GP) Sentinel Network represents the only data source on diabetes incidence. This study describes the trends in Diabetes incidence, between 1992 and 2015, and estimate projections for the future incidence rates in Portugal until 2024.

METHODS

An ecological time-series study was conducted using data from GP Sentinel Network between 1992 and 2015. Family doctors reported all new cases of Diabetes in their patients' lists. Annual trends were estimated through Poisson regression models as well as the future incidence rates (until 2024), sex and age group stratified. Incidence rate projections were adjusted to the distribution of the resident Portuguese population given Statistics Portugal projections.

RESULTS

The average increase in Diabetes incidence rate was in total 4.29% (CI95% 3.80-4.80) per year under study. Until 1998-2000, the annual incidence rate was higher in women, and from 1998-2000 to 2013-2015 turn out to be higher in men. The incidence rate projected for 2022-2024 was 972.77/10(5) inhabitants in total, and 846.74/10(5) and 1114.42/10(5), respectively, in women and men.

CONCLUSIONS

This is the first study in Portugal to estimate diabetes incidence rate projections. The disturbing reported projections seem realistic if things continue as in the past. Actually, effective public health policies will need to be undertaken to minimize this alarming future scenario.

Use of Electronic Health Records and Geographic Information Systems in Public Health Surveillance of Type 2 Diabetes: A Feasibility Study

Background

Data routinely collected in electronic health records (EHRs) offer a unique opportunity to monitor chronic health conditions in real-time. Geographic information systems (GIS) may be an important complement in the analysis of those data.

Objective

The aim of this study was to explore the feasibility of using primary care EHRs and GIS for population care management and public health surveillance of chronic conditions, in Portugal. Specifically, type 2 diabetes was chosen as a case study, and we aimed to map its prevalence and the presence of comorbidities, as well as to identify possible populations at risk for cardiovascular complications.

Methods

Cross-sectional study using individual-level data from 514 primary care centers, collected from three different types of EHRs. Data were obtained on adult patients with type 2 diabetes (identified by the International Classification of Primary Care [ICPC-2] code, T90, in the problems list). GISs were used for mapping the prevalence of diabetes and comorbidities (hypertension, dyslipidemia, and obesity) by parish, in the region of Lisbon and Tagus Valley. Descriptive statistics and multivariate logistic regression were used for data analysis.

Results

We identified 205,068 individuals with the diagnosis of type 2 diabetes, corresponding to a prevalence of 5.6% (205,068/3,659,868) in the study population. The mean age of these patients was 67.5 years, and hypertension was present in 71% (144,938/205,068) of all individuals. There was considerable variation in diagnosed comorbidities across parishes. Diabetes patients with concomitant hypertension or dyslipidemia showed higher odds of having been diagnosed with cardiovascular complications, when adjusting for age and gender (hypertension odds ratio [OR] 2.16, confidence interval [CI] 2.10-2.22; dyslipidemia OR 1.57, CI 1.54-1.60).

Conclusions

Individual-level data from EHRs may play an important role in chronic disease surveillance, namely through the use of GIS. Promoting the quality and comprehensiveness of data, namely through patient involvement in their medical records, is crucial to enhance the feasibility and usefulness of this approach.

Diabetes hinders community-acquired pneumonia outcomes in hospitalized patients

OBJECTIVES

This study aimed to estimate the prevalence of diabetes mellitus (DM) in hospitalized patients with community-acquired pneumonia (CAP) and its impact on hospital length of stay and in-hospital mortality.

RESEARCH DESIGN AND METHODS

We carried out a retrospective, nationwide register analysis of CAP in adult patients admitted to Portuguese hospitals between 2009 and 2012. Anonymous data from 157 291 adult patients with CAP were extracted from the National Hospital Discharge Database and we performed a DM-conditioned analysis stratified by age, sex and year of hospitalization.

RESULTS

The 74 175 CAP episodes that matched the inclusion criteria showed a high burden of DM that tended to increase over time, from 23.7% in 2009 to 28.1% in 2012. Interestingly, patients with CAP had high DM prevalence in the context of the national DM prevalence. Episodes of CAP in patients with DM had on average 0.8 days longer hospital stay as compared to patients without DM (p<0.0001), totaling a surplus of 15 370 days of stay attributable to DM in 19 212 admissions. In-hospital mortality was also significantly higher in patients with CAP who have DM (15.2%) versus those who have DM (13.5%) (p=0.002).

CONCLUSIONS

Our analysis revealed that DM prevalence was significantly increased within CAP hospital admissions, reinforcing other studies' findings that suggest that DM is a risk factor for CAP. Since patients with CAP who have DM have longer hospitalization time and higher mortality rates, these results hold informative value for patient guidance and healthcare strategies.

Geografias da Diabetes Mellitus em Portugal: Como as Condições do Contexto Influenciam o Risco de Morrer

<strong>Introduction:</strong> Diabetes Mellitus is a public health problem that is on the increase throughout the world, including in Portugal. This paper aims to identify the changing geographic pattern of this cause of death in Portugal and its association with sociomaterial deprivation.<br /><strong>Material and Methods:</strong> This is a transversal ecological study of the deaths by Diabetes Mellitus in Portuguese municipalities in three periods (1989-1993, 1999-2003 and 2006-2010). It uses a Bayesian hierarchical model in order to obtain a smooth standardized mortality ratio and the relative risk of death by Diabetes Mellitus associated to sociomaterial deprivation.<br /><strong>Results:</strong> In 1989-1993, the highest smooth standardized mortality ratio values were found in coastal urban municipalities (80% of municipalities with smooth standardized mortality ratio ≥ 161, of which 60% are urban); in 2006-2010, the opposite was found, with the highest smooth standardized mortality ratio values occurring in rural areas in southern inland regions (76.9% of municipalities with smooth standardized mortality ratio ≥ 161, of which 69.2% are rural), particularly the Alentejo. The relative risk of death by Diabetes Mellitus increases with vulnerability associated to social and economic conditions in the area of residence, and is significant in the last two periods (relative risk: 1.00; IC95%: 0.98-1.02).<br /><strong>Discussion:</strong> Diabetes Mellitus presents a geographic pattern marked by coastal-inland and urban-rural asymmetry. However, this has been altering over the last twenty years. 48% of the population reside in municipalities where the smooth standardized mortality ratio has increased in the last twenty years, particularly in the rural areas of inland Portugal.<br /><strong>Conclusion: </strong>The highest smooth standardized mortality ratio are currently found in rural municipalities with the highest index of sociomaterial deprivation.<br /><strong>Keywords:</strong> Demography; Diabetes Mellitus/epidemiology; Diabetes Mellitus/mortality; Portugal; Socioeconomic Factors.

[The geography of diabetes mellitus in Portugal: how context influence the risk of dying]

INTRODUCTION

Diabetes Mellitus is a public health problem that is on the increase throughout the world, including in Portugal. This paper aims to identify the changing geographic pattern of this cause of death in Portugal and its association with sociomaterial deprivation.

MATERIAL AND METHODS

This is a transversal ecological study of the deaths by Diabetes Mellitus in Portuguese municipalities in three periods (1989-1993, 1999-2003 and 2006-2010). It uses a Bayesian hierarchical model in order to obtain a smooth standardized mortality ratio and the relative risk of death by Diabetes Mellitus associated to sociomaterial deprivation.

RESULTS

In 1989-1993, the highest smooth standardized mortality ratio values were found in coastal urban municipalities (80% of municipalities with smooth standardized mortality ratio ≥ 161, of which 60% are urban); in 2006-2010, the opposite was found, with the highest smooth standardized mortality ratio values occurring in rural areas in southern inland regions (76.9% of municipalities with smooth standardized mortality ratio ≥ 161, of which 69.2% are rural), particularly the Alentejo. The relative risk of death by Diabetes Mellitus increases with vulnerability associated to social and economic conditions in the area of residence, and is significant in the last two periods (relative risk: 1.00; IC95%: 0.98-1.02).

DISCUSSION

Diabetes Mellitus presents a geographic pattern marked by coastal-inland and urban-rural asymmetry. However, this has been altering over the last twenty years. 48% of the population reside in municipalities where the smooth standardized mortality ratio has increased in the last twenty years, particularly in the rural areas of inland Portugal.

CONCLUSION

The highest smooth standardized mortality ratio are currently found in rural municipalities with the highest index of sociomaterial deprivation.

A Mortalidade por Diabetes em Portugal

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[Therapeutic patient education in diabetes management]

Late complications of type 1 and type 2 diabetes can also be effectively avoided or delayed using active intervention and available therapies. Despite these facts, the percentage of people with diabetes following the therapy proposed by health care professionals is quite low. People with diabetes or any other chronic disease have to be involved in their own treatment. Basic knowledge is very important for the patient but the reinforcement of appropriate attitudes and a continuous process of motivation is fundamental in changing habits and behaviour. We need to educate patients, giving them the tools and skills to manage their disease, allowing them to become autonomous, empowering them. In the Therapeutic Patient Education model the patient is no longer the object but instead one of the actors in the process. He becomes part of the team and part of the solution. Goals are agreed as a result of input of the patient's desires, details of his daily life, his perceptions and the HCP's biomedical objectives. The patient takes care of himself and will, step by step, become aware of the consequences of his actions, in collaboration with his health team.

Prevalence of chronic kidney disease and associated risk factors, and risk of end-stage renal disease: data from the PREVADIAB study

BACKGROUND/AIMS

Chronic kidney disease (CKD) is a growing public health problem. However, data on risk factors and prevalence of CKD exist only in a small number of countries. Portugal has the highest incidence of end-stage renal disease (ESRD) among European countries, but there are huge disparities among countries. Whether these disparities reflect differences in risk factors, prevalence of CKD or other factors is currently unknown.

METHODS

We analyzed data from a nationally representative sample of 5,167 subjects, and estimated the prevalence of CKD and associated risk factors, and combined these prevalence estimates with available data on ESRD.

RESULTS

The prevalence of risk factors such as diabetes (11.7%), obesity (33.7%), and metabolic syndrome (41.5%) was similar to that in the US, but greater than in most European countries. The prevalence of CKD stages 3-5 was 6.1%, which is similar to that in other Western countries. The risk of ESRD was greater than in other European countries, but lower than in the US.

CONCLUSION

The high incidence of ESRD among the Portuguese population is not due to a greater prevalence of CKD. A higher rate of progression associated with the high prevalence of risk factors may account for the high incidence of ESRD. The role of unmeasured factors needs to be evaluated in further studies.

Independent factors associated with depression in type 1 diabetes mellitus

Diabetes has been associated with depression since Thomas Willis' work in 1684 (Rubin and Peyrot in Diabetes Metab Rev 18:173-175, 2002). The aim of this study is to identify social and clinical factors independently associated with depression in individuals with type 1 diabetes. We carried out a descriptive transversal study with 110 type 1 diabetes patients, administered a questionnaire and obtained demographical and diabetes-related data (number of years from diagnosis, initial admission at diagnosis, glycated hemoglobin, number of complications, insulin dose, number of insulin injections per day, admission for ketoacidosis or hypoglycemia at diagnosis, and specific diabetes complications such as nephropathy, retinopathy, peripheral neuropathy, coronariopathy, and amputation). Depressive symptoms were quantified using the Hamilton Score. We used T tests to investigate potential relations between the covariates and depression (Hamilton score). We concluded the following: as few as 10% of our patients had glycated hemoglobin under 7%; women had more symptoms of depression, and there are four independent factors associated with depression in individuals with type 1 diabetes mellitus: age, Graffar score, admission for ketoacidosis, and insulin dose.

First diabetes prevalence study in Portugal: PREVADIAB study

AIMS

Diabetes is a growing worldwide problem. Ascertaining its prevalence is vital as a starting point to establish and measure the success of health interventions. This study aimed to determine the prevalence of Type 2 diabetes and 'pre-diabetes', defined as impaired fasting glucose and impaired glucose tolerance, in the Portuguese population aged between 20 and 79 years.

METHODS

Considering the number of inhabitants between 20 and 79 years old, statistical units were selected that were representative regionally and nationally. The total sample comprised 5167 subjects. National prevalence was calculated. Analyses were performed on all those without previously known diabetes using World Health Organization reference diagnostic criteria.

RESULTS

We found a diabetes prevalence of 11.7% (95% confidence interval 10.8-12.6%), with a significant difference between men (14.2%; 95% confidence interval 12.5-15.5%) and women (9.5%; 95% confidence interval 8.5-10.6%). While 6.6% of the subjects had previously been diagnosed with diabetes, 5.1% were undiagnosed. By age groups, 2.4% of the population between 20 and 39 years, 12.6% of people from 40 to 59 years old and 26.3% of those aged between 60 and 79 years had diabetes. Prevalence of 'pre-diabetes' (impaired fasting glucose, impaired glucose tolerance or both) in the population was 23.3%.

CONCLUSIONS

Diabetes has a high prevalence in Portugal. If 'pre-diabetes' is also considered, about one-third (34.9%) of the population aged 20-79 years is affected. A greater number of males were found to have diabetes. We detected a high percentage of people with undiagnosed diabetes (43.6%).

Quality indicators for the prevention of type 2 diabetes in Europe--IMAGE

BACKGROUND

The marked increase of type 2 diabetes necessitates active development and implementation of efficient prevention programs. A European level action has been taken by launching the IMAGE project to unify and improve the various prevention management concepts, which currently exist within the EU. This report describes the background and the methods used in the development of the IMAGE project quality indicators for diabetes primary prevention programs. It is targeted to the persons responsible for diabetes prevention at different levels of the health care systems.

METHODS

Development of the quality indicators was conducted by a group of specialists representing different professional groups from several European countries. Indicators and measurement recommendations were produced by the expert group in consensus meetings and further developed by combining evidence and expert opinion.

RESULTS

The quality indicators were developed for different prevention strategies: population level prevention strategy, screening for high risk, and high risk prevention strategy. Totally, 22 quality indicators were generated. They constitute the minimum level of quality assurance recommended for diabetes prevention programs. In addition, 20 scientific evaluation indicators with measurement standards were produced. These micro level indicators describe measurements, which should be used if evaluation, reporting, and scientific analysis are planned.

CONCLUSIONS

We hope that these quality tools together with the IMAGE guidelines will provide a useful tool for improving the quality of diabetes prevention in Europe and make different prevention approaches comparable.

Take action to prevent diabetes--the IMAGE toolkit for the prevention of type 2 diabetes in Europe

When we ask people what they value most, health is usually top of the list. While effective care is available for many chronic diseases, the fact remains that for the patient, the tax payer and the whole of society: prevention is better than cure. Diabetes and its complications are a serious threat to the survival and well-being of an increasing number of people. It is predicted that one in ten Europeans aged 20-79 will have developed diabetes by 2030. Once a disease of old age, diabetes is now common among adults of all ages and is beginning to affect adolescents and even children. Diabetes accounts for up to 18 % of total healthcare expenditure in Europe. The good news is that diabetes is preventable. Compelling evidence shows that the onset of diabetes can be prevented or delayed greatly in individuals at high risk (people with impaired glucose regulation). Clinical research has shown a reduction in risk of developing diabetes of over 50 % following relatively modest changes in lifestyle that include adopting a healthy diet, increasing physical activity, and maintaining a healthy body weight. These results have since been reproduced in real-world prevention programmes. Even a delay of a few years in the progression to diabetes is expected to reduce diabetes-related complications, such as heart, kidney and eye disease and, consequently, to reduce the cost to society. A comprehensive approach to diabetes prevention should combine population based primary prevention with programmes targeted at those who are at high risk. This approach should take account of the local circumstances and diversity within modern society (e.g. social inequalities). The challenge goes beyond the healthcare system. We need to encourage collaboration across many different sectors: education providers, non-governmental organisations, the food industry, the media, urban planners and politicians all have a very important role to play. Small changes in lifestyle will bring big changes in health. Through joint efforts, more people will be reached. The time to act is now.

A European evidence-based guideline for the prevention of type 2 diabetes

BACKGROUND

The prevalence and socioeconomic burden of type 2 diabetes (T2DM) and associated co-morbidities are rising worldwide.

AIMS

This guideline provides evidence-based recommendations for preventing T2DM.

METHODS

A European multidisciplinary consortium systematically reviewed the evidence on the effectiveness of screening and interventions for T2DM prevention using SIGN criteria.

RESULTS

Obesity and sedentary lifestyle are the main modifiable risk factors. Age and ethnicity are non-modifiable risk factors. Case-finding should follow a step-wise procedure using risk questionnaires and oral glucose tolerance testing. Persons with impaired glucose tolerance and/or fasting glucose are at high-risk and should be prioritized for intensive intervention. Interventions supporting lifestyle changes delay the onset of T2DM in high-risk adults (number-needed-to-treat: 6.4 over 1.8-4.6 years). These should be supported by inter-sectoral strategies that create health promoting environments. Sustained body weight reduction by >or= 5 % lowers risk. Currently metformin, acarbose and orlistat can be considered as second-line prevention options. The population approach should use organized measures to raise awareness and change lifestyle with specific approaches for adolescents, minorities and disadvantaged people. Interventions promoting lifestyle changes are more effective if they target both diet and physical activity, mobilize social support, involve the planned use of established behaviour change techniques, and provide frequent contacts. Cost-effectiveness analysis should take a societal perspective.

CONCLUSIONS

Prevention using lifestyle modifications in high-risk individuals is cost-effective and should be embedded in evaluated models of care. Effective prevention plans are predicated upon sustained government initiatives comprising advocacy, community support, fiscal and legislative changes, private sector engagement and continuous media communication.

Two novel variants in the thyroxine-binding globulin (TBG) gene behind the diagnosis of TBG deficiency

OBJECTIVE

Search for germline mutations in the thyroxine-binding globulin (TBG) gene of two unrelated Portuguese females of Caucasian origin in whom the diagnosis of TBG deficiency was suspected because of suppressed TSH despite marginally low total thyroxine and tri-iodothyronine.

DESIGN AND METHODS

Screening for germline mutations was conducted by non-radioactive PCR-SSCP analysis. The variants documented by this approach were characterized by sequencing. Moreover, in order to define whether they were mutations or polymorphisms we looked for the same variants analysing 100 alleles at random. To achieve this goal we used, alternatively, restriction analysis and the minisequencing method with an automated capillary electrophoresis system and fluorescent-labelled dideoxynucleotides.

RESULTS AND CONCLUSIONS

Two novel variants, one in each patient, were identified. One, involved codon 23 (TCA-->TAA) and the other, codon 223 (CAA-->TAA). Analysis of 50 DNA samples, randomly chosen, revealed that all were homozygous for the wild variant at codon 23. One of them was heterozygous for the variant CAA-->TAA at codon 223. This sample was found to correspond to a Caucasian female in whom serum TBG proved to be not detected. Since both variants identified result in stop codons likely to induce truncated TBG proteins, they are probably responsible for the TBG phenotype observed in the individuals studied.

An unusual case of papillary carcinoma of the thyroid with cutaneous and breast metastases only

Cutaneous metastases of thyroid carcinoma are infrequent and, when present, are usually located in the vicinity of a widespread primary tumor. Breast metastases from these tumors are even less common. We report the case of a 64-year-old female with a toxic multinodular goiter in whom a fine-needle biopsy, performed in 1985 at the age of 52, was suggestive of papillary carcinoma of the thyroid. Total thyroidectomy for a papillary carcinoma, follicular variant, was performed in 1988. Four months after surgery, a cutaneous metastasis was discovered in the right thigh. Surgical excision of the lesion followed by treatment with radioactive iodine decreased serum Tg levels from 7495 to 3.3 micrograms/l. Under suppressive therapy with L-thyroxine, serum Tg remained undetectable for the next 4 years. Then, serum Tg levels rose to 3.9-5.6 micrograms/l and a second cutaneous metastasis was removed from the abdominal wall. The patient was again treated with radioactive iodine and the post-treatment whole-body scan did not show any area of increased uptake of the radionuclide. However, serum Tg levels under suppression with L-thyroxine remained elevated at 4-20 micrograms/l for the next 2 years. In August 1995, a 1.5 cm nodule was found in the right breast. Cytological examination was suggestive of a breast metastasis from thyroid carcinoma and the lesion was removed by enucleation. This proved to be a metastasis from a papillary carcinoma of the thyroid. Elevated (19-44 micrograms/l) serum Tg levels persisted postoperatively. A third cutaneous metastasis was revealed by 131I scintigraphy in the right buttock and surgically removed in December 1996. Serum Tg levels have remained undetectable since then. To the best of our knowledge, this is a unique case of a papillary carcinoma of the thyroid with a propensity to metastasize only to the skin and breast during a follow-up of 11 years.

ACTH-producing carcinoma of the pituitary with haematogenic metastases

The case report is presented of a 47-year-old white woman with Cushing's disease treated by bilateral adrenalectomy in June 1981. A first computed tomography (CT) scan in September 1984 showed a voluminous pituitary adenoma with invasion of the sphenoid sinus and left parasellar extension. The tumour increased progressively in size, a suprasellar extension developed and the optic chiasm was eventually affected. In March 1988 and June 1989 the patient underwent two surgeries for the pituitary tumour, the second followed by radiotherapy. During this period, the ACTH values varied between 100 pmol/l and 403 pmol/l (normal: < 13 pmol/l). After radiotherapy, a progressive shrinking of the tumour was observed and the ACTH concentrations decreased to a lowest value of 27.5 pmol/l. The patient was clinically well until September 1993 when, suddenly, the plasma ACTH concentration increased to very high levels (greater than 965 pmol/l). There was no evidence of tumour growth on the sellar CT scan. In January 1995, an ACTH-producing pituitary carcinoma was diagnosed, based on the presence of bone metastases. The patient died in May 1995.

[The prevention of insulin-dependent diabetes mellitus]

At the present time, there are markers which we can use to identify individuals with a high susceptibility of developing insulin-dependent diabetes mellitus (IDDM) years before the onset of the disease. Insulin-dependent diabetes mellitus is an autoimmune disease strongly associated with HLA antigens DR3 and DR4. In this manuscript, we discuss the usefulness of several markers, such as islet cell antibodies, insulin autoantibodies and glutamic acid decarboxylase antibodies, to identify individuals with a high susceptibility to IDDM before the disease is clinically evident. Monitoring first phase insulin release during intravenous glucose administration is a useful index of residual beta cell function that can be used to detect individuals who are close to insulin dependence. Several drugs have been used to prevent the development of IDDM. These include immunodepressors, anti-inflammatory agents, non-specific immunomodulators and free radical scavengers. Due to their toxicity, studies employing aziothioprine and cyclosporin were discontinued. Other agents, such as tetrandrin and lymphotoxin, are now restricted to non-human trials. Currently, two large-scale multicentric human trials, one in Europe using nicotinamide (European Nicotinamide Diabetes Intervention Trial, ENDIT) and the other in the USA using insulin (Diabetes Prevention Trial), are now in full activity and will test the benefits of these drugs in the prophylaxis of IDDM in highly susceptible individuals.