Islet cell antibodies are not specifically associated with insulin-dependent diabetes in Tanzanian Africans

The phenotype of type 1 diabetes in sub-Saharan Africa

The phenotype of type 1 diabetes in Africa, especially sub-Saharan Africa, is poorly understood. Most previously conducted studies have suggested that type 1 diabetes may have a different phenotype from the classical form of the disease described in western literature. Making an accurate diagnosis of type 1 diabetes in Africa is challenging, given the predominance of atypical diabetes forms and limited resources. The peak age of onset of type 1 diabetes in sub-Saharan Africa seems to occur after 18-20 years. Multiple studies have reported lower rates of islet autoantibodies ranging from 20 to 60% amongst people with type 1 diabetes in African populations, lower than that reported in other populations. Some studies have reported much higher levels of retained endogenous insulin secretion than in type 1 diabetes elsewhere, with lower rates of type 1 diabetes genetic susceptibility and HLA haplotypes. The HLA DR3 appears to be the most predominant HLA haplotype amongst people with type 1 diabetes in sub-Saharan Africa than the HLA DR4 haplotype. Some type 1 diabetes studies in sub-Saharan Africa have been limited by small sample sizes and diverse methods employed. Robust studies close to diabetes onset are sparse. Large prospective studies with well-standardized methodologies in people at or close to diabetes diagnosis in different population groups will be paramount to provide further insight into the phenotype of type 1 diabetes in sub-Saharan Africa.

Survival of children and youth with type 1 diabetes mellitus in Tanzania

INTRODUCTION

Survival from type 1 diabetes Mellitus is low in lower-income countries with underdeveloped health systems. Support programs from partners like life for a child (LFAC) and changing diabetes in children (CDiC) were implemented in Tanzania in 2005 to provide diabetes care to children and youth. No evaluation of survival has been done since their implementation.

OBJECTIVE

To assess the survival of children and youth living with diabetes mellitus (CYLDM) in Tanzania.

METHODS

A retrospective data collection from 39 clinics of CYLDM was done by extracting data from the diabetes registry between 1991 and 2019. Three cohort were analyzed (1) Cohort 1991-2004 (pre-implementation), (2) Cohort 2005-2010 (during implementation), and (3) 2011-2019 (after the implementation of LFAC/CDiC). Data were analyzed using STATA-version 14.

RESULTS

A total of 3822 data of CYLDM were extracted, mean age at diagnosis was 13.8 (±5) years. Approximately fifty-one percent (50.8%) were male. The total observation time was 28 years, and the Median duration of diabetes of 5 (IQR2, 8) years. Total death was 95 (3%), with a mean age at death of 17.7 (SD 4.7) years. The last cohort (2011-2019) had more diagnosis 2353 (72.7%), as compared to the <2005 cohort with only 163(5%). The survival improved from 59% before 2005 to 69% in the last cohort (2011-2019).

CONCLUSION

The implemented programs have facilitated the diagnosis and retention of CYLDM in the health care system. In doing so, it has also increased the survival probability in Tanzania compared to the early 90s.

Global and regional estimates of the morbidity due to type I diabetes among children aged 0-4 years: a systematic review and analysis

Background

Epidemiology of type 1 diabetes mellitus (T1DM) among children aged 0-4 years globally is not well understood. We aim to assess the incidence of T1DM in low- and middle-income countries (LMIC) by conducting a systematic review of previous reports. We also aim to address possible contribution to child mortality and to identify any temporal trends.

Methods

A systematic review was performed using a carefully designed search strategy to explore MEDLINE, EMBASE and Global Health databases. Data was extracted from all studies that satisfied the inclusion criteria –a total of 83 records extracted from 26 830 sources that were analysed. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process to assess quality of evidence and applied meta-analysis approaches to assess global and regional incidence and time trends.

Results

The overall pooled incidence of T1DM in children aged 0-4 years globally is 11.2 (95% CI = 10.0-12.3) per 100 000 child years. The regional incidence were the highest for European Region A (EUR A) at 15.5 (95% CI = 13.5-17.5) per 100 000 child years. EUR C had the incidence of 10.0 (95% CI = 6.5-13.6) and EUR B 5.8 (95% CI = 4.7-7.0), Region of the Americas A (AMR A) 11.4 (95% CI = 7.8-14.9), AMR B of 2.5 (95% CI = 0.2-4.8), Eastern Mediterranean Region (EMR B) 7.1 (95% CI = 4.2-10.0) and Western Pacific Region (WPR A) 7.0 (95% CI = 2.9-11.0) per 100 000 child years, while other regions had very low rates or no data. When data points were categorised in the study periods and re-analysed, an increasing trend of the T1DM incidence was observed, with the incidence of 20.9 (95% CI = 7.8-34.1) per 100 000 child years in the years 2010-2015, preceded by 13.2 (95% CI = 11.0-15.5) in 2000-2009 study period, 10.0 (95% CI = 8.4-11.7) in 1990-1999 and 8.3 (95% CI = 5.1-11.6) in 1980-1989, respectively. Although the data are scarce, and variation and uncertainty are large, we estimated that the number of new cases of T1DM among children aged 0-4 years in the world each year is between 100 000 and 150 000.

Conclusions

The identified large variation in incidence estimates for different parts of the world, along with scarcity of information and the identified strong temporal increase in T1DM incidence suggest a clear need for further research into this subject.

Clinical and biological characteristics of diabetic patients under age 40 in Cameroon: relation to autoantibody status and comparison with Belgian patients

AIMS

We investigated the prevalence of diabetes autoantibodies (Abs) in Cameroonian patients and controls, assessed their contribution in disease classification and compared results with data from Belgium.

METHODS

Abs against GAD (GADA), IA-2 (IA-2A) and zinc transporter 8 (ZnT8A) were assessed in 302 recently diagnosed Cameroonian patients with diabetes and 184 control subjects without diabetes aged below 40 years.

RESULTS

Only 27 (9%) Cameroonian patients were younger than 15 years. Overall, 29% of patients presented at least one diabetes-associated antibody vs 9% in healthy controls (24% vs 7% for GADA (p<0.001), 10% vs 3% for IA-2A (p<0.006), 4% vs 2% for ZnT8A). Ab(+) patients had lower C-peptide levels (p<0.001), were more often insulin-treated (p<0.002) and were as frequently diagnosed with type 1 diabetes as Ab(-) patients. Only 43% of Ab(+) patients aged 15-39 years were clinically classified as having type 1 diabetes in Cameroon vs 96% in Belgium (p<0.001). Not one Ab(+) Cameroonian patient carried HLA-DQ2/DQ8 genotype vs 23% of Belgian Ab(+) patients (p<0.001). Younger age at diagnosis and antibody positivity were independent predictors of insulin therapy. Ab(+) Cameroonian patients were older (p<0.001), had higher BMI (p<0.001) and lower Ab titers than Belgian Ab(+) patients. In ketonuric patients, prevalence of autoantibodies was similar as in non-ketonuric patients.

CONCLUSIONS

In Cameroonian patients with diabetes aged under 40 years, antibody-positivity is not clearly related to disease phenotype, but may help predict the need for insulin treatment.

Insulin-requiring diabetes in Ethiopia: associations with poverty, early undernutrition and anthropometric disproportion

BACKGROUND/OBJECTIVES

Most insulin-requiring diabetes patients in Ethiopia have an atypical form of the disease, which resembles previous descriptions of malnutrition-related diabetes. As so little is known about its aetiology, we have carried out a case-control study to evaluate its social and nutritional determinants.

SUBJECTS/METHODS

Men and women with insulin-requiring diabetes (n=107), aged 18-40 years, were recruited in two centres, Gondar and Jimma, 750 km northwest and 330 km southwest of the capital, Addis Ababa, respectively. Controls of similar age and sex (n=110) were recruited from patients attending other hospital clinics.

RESULTS

Diabetes was strongly associated with subsistence farming, odds ratio=3.5 (95% confidence interval: 1.5-7.8) and illiteracy/low levels of education, odds ratio=4.0 (2.0-8.0). Diabetes was also linked with a history of childhood malnutrition, odds ratio=5.5 (1.0-29.0) the mother's death during childhood, odds ratio=3.9 (1.0-14.8), and markers of poverty including poorer access to sanitation (P=0.004), clean water (P=0.009), greater overcrowding (P=0.04), increased distance from the clinic (P=0.01) and having fewer possessions (P=0.01). Compared with controls, people with diabetes had low mid upper arm circumference, body mass index (BMI) and fat/lean body mass (P<0.01). In addition, men with the disease tended to be shorter, were lighter (P=0.001), with reduced sitting height (P=0.015) and reduced biacromial (P=0.003) and bitrochanteric (P=0.008) diameters.

CONCLUSIONS

Insulin-requiring diabetes in Ethiopia is strongly linked with poor education and markers of poverty. Men with the disease have associated disproportionate skeletal growth. These findings point towards a nutritional aetiology for this condition although the nature of the nutritional deficiency and its timing during growth and development remains obscure.

Diabetes in sub-Saharan Africa

In Sub-Saharan Africa, prevalence and burden of type 2 diabetes are rising quickly. Rapid uncontrolled urbanisation and major changes in lifestyle could be driving this epidemic. The increase presents a substantial public health and socioeconomic burden in the face of scarce resources. Some types of diabetes arise at younger ages in African than in European populations. Ketosis-prone atypical diabetes is mostly recorded in people of African origin, but its epidemiology is not understood fully because data for pathogenesis and subtypes of diabetes in sub-Saharan African communities are scarce. The rate of undiagnosed diabetes is high in most countries of sub-Saharan Africa, and individuals who are unaware they have the disorder are at very high risk of chronic complications. Therefore, the rate of diabetes-related morbidity and mortality in this region could grow substantially. A multisectoral approach to diabetes control and care is vital for expansion of socioculturally appropriate diabetes programmes in sub-Saharan African countries.

Islet cell autoantibodies in African patients with Type 1 and Type 2 diabetes in Dar es Salaam Tanzania: a cross sectional study

Background

The aim of the present study was to assess the occurrence of glutamic acid decarboxylase autoantibodies (GADA) and insulinoma antigen 2 autoantibodies (IA2A) among patients of African origin in Dar es Salaam, Tanzania and to compare the occurrence of autoimmune mediated Type 1 diabetes with findings previously reported from the same place and from other African diabetic populations.

Methods

Two hundred and forty five patients from the diabetic clinic at Muhimbili Hospital were recruited for a cross sectional study. Patients were clinically classified into groups with Type 1 (T1D) and Type 2 diabetes (T2D); there were 94 patients with T1D and 151 with T2D. Autoantibodies for GAD and IA2 were measured with an assay based on radioligand binding. Fasting and random blood glucose, HbA1c, and C-peptide levels were also determined.

Results

Of the patients with T1D, 28 (29.8%) were GADA positive and 20 (21.3%) were IA2A positive. The overall occurrence of any autoantibody was 42.6%. The GAD and IA2 autoantibodies were detected more frequently among patients with T1D than among patients with T2D (P < 0.001). A higher autoantibody prevalence was observed with combined GADA and IA2A measurements compared to individual autoantibody measurements; 40 (42.6%) patients with T1D versus 11 (7.3%) with T2D had at least one positive autoantibody titer. There was no correlation between duration of disease and detection of autoantibodies in patients with T1D. There was a strong association with family history of diabetes among the autoantibody positive versus autoantibody negative patients with T1D (p < 0.01).

Conclusion

The prevalence of GAD and IA2 autoantibodies among African patients with T1D in Dar es Salaam was the same as that reported previously for South Africa and Ethiopia. It was much higher than the prevalence of islet cell autoantibodies (ICA) reported from the same clinic about 15 years ago. For unknown reasons the prevalence of pancreatic related autoantibodies in this African population is lower than the prevalence found among Caucasian populations.

Beta cell function and response to treatment in Nigerians with Type 2 diabetes mellitus

There are scant data from African populations on the association between beta-cell function and response to treatment with oral hypoglycaemic agents in Type 2 diabetes mellitus (T2DM). Fasting plasma C-peptide (FCP) and glucagon-stimulated C-peptide (GSCP) levels were measured in 116 Nigerians with T2DM at a university teaching hospital. After 9 months of follow-up and treatment, they were categorized into three groups based on response to treatment: (A) good control but not on maximum sulphonylurea (SU) therapy, (B) inadequate control but not on maximum SU therapy and (C) on maximum SU therapy+/-insulin or biguanide. Logistic regression models were used to investigate how well C-peptide levels predicted the subjects belonging to Group C who are likely to require insulin. The mean FCP and mean GSCP levels of Group C were significantly lower than in the other groups (p=0.024; p= <0.001 respectively). A GSCP cut-off value of < or =1.3 ng/mL predicted membership of Group C with 85% sensitivity and 89% specificity while a cut-off of < or =1.8 ng/mL was associated with 91% sensitivity and 66% specificity. In resource-poor settings where inadequate treatment are common, estimation of GSCP may be useful in predicting treatment response and should be weighed against the cost of inadequate therapy with higher morbidity and mortality.

A Tanzanian perspective on the nutrition transition and its implications for health

OBJECTIVE

The purpose of this paper is to describe social and economic changes related to shifts in diet and activity and to present prevalences for chronic diseases associated with the nutrition transition.

DESIGN

Observations about social changes are descriptive, based on published reports and personal observations. Prevalence and trends data are based on a Ministry of Health published report and, for infants and toddlers, on primary data.

SETTING

Disease prevalences for diabetes mellitus and hypertension are taken from four sites, representing underdeveloped, semi-developed and well-developed rural communities and Dar es Salaam, the largest city in Tanzania. The prevalences of underweight and overweight for infants and toddlers are taken from a small periurban clinic in Tanzania.

SUBJECTS

Adults over 15 years of age are included in the prevalence data for chronic disease. The urban sample is stratified by occupation and ethnicity. The data for infants and toddlers include newborns to those aged 23 months.

RESULTS

An increase in the prevalence of diabetes and hypertension was observed. Simultaneously, there have been rapid changes in diet and physical activity related to urbanisation and modernisation. The highest prevalences for diabetes and hypertension were among high-ranking executives.

CONCLUSION

The increase in chronic disease could be related to the rise in the number of high-ranking executives. Simultaneously, per capita income has gone down, and malnutrition prevalence has risen. Programmes are being developed to simultaneously monitor trends in overweight while preventing protein-energy malnutrition and micronutrient deficiency.

Type 1 1/2 diabetes: myth or reality?

The disease process in classical Type 1 diabetes patients (IDDM) is believed to be autoimmune. In contrast, the disease process in classical Type 2 diabetes patients (NIDDM) is not autoimmune and a decreased sensitivity to insulin action is the main abnormality. The clinical distinction of Type 1 diabetes versus Type 2 diabetes is recognized to be imperfect and has limitations. There is a group of individuals (Type 1 1/2 diabetes), who present like typical NIDDM, but have some of the immunological and clinical features of IDDM. We review the current medical literature on Type 1 1/2 diabetes with special reference to its clinical characteristics, natural history and pathophysiology. Since the distinction between these two forms of diabetes may have important therapeutic implications especially with regards to the benefits of insulin therapy in patients with Type 1 1/2 diabetes and because of the need for uniformity in its diagnosis we recommend that both clinical plus biochemical criteria (the presence of ICA and/or GAD Ab, HLA typing and tests to quantify beta cell function) be used to make a diagnosis. Comparative studies in the area of cytokine production, T cell reactivity and autoantibody clustering between classic Type 1 diabetes and Type 1 1/2 diabetes patients are needed as are studies with the animal model of Type 1 1/2 diabetes, Psammomys obesus.

A pilot epidemiologic study of diabetes mellitus in the Sudan

Records of 523 consecutive diabetic patients attending a diabetic clinic in Wad Madeni, Central Region, Sudan, were reviewed to determine epidemiologic features and the relation between their diabetes and nutritional state. The male to female ratio was 0.97:1. The age at diagnosis ranged between 0-61 years with a mean age of 51.7 +/- 11.9 years for males and 49.4 +/- 11.4 for females. Obesity was a feature, in that 47.4% of females and 30% of males were determined to be in excess of normal body mass index (BMI) standards. A family history of diabetes was present in 67% of cases. Hypertension was present in 38% of cases; it was slightly more common among females than males (52% vs 48%), respectively. Insulin was employed for control of diabetes in 75% of cases, and oral hypoglycaemics in 20%. The remainder were on diet therapy alone. Thirty-four percent of the patients are rural dwellers that should be saved from disabling and even fatal complications of the disease in combination with malnutrition and infectious diseases that hasten death in rural areas. It is hoped that the interest of those concerned regarding public health implications of the findings in this study will be stimulated.

The ethnic distribution of antibodies to glutamic acid decarboxylase: presence and levels of insulin-dependent diabetes mellitus in Europid and Asian subjects

Our objective was to ascertain the frequency of antibodies to glutamic acid decarboxylase (GAD) in Europids and four Asian ethnic groups with insulin-dependent diabetes mellitus (IDDM) to gain insight into why the prevalence and incidence of IDDM varies so widely among ethnic and/or geographically diverse population groups. The subjects in this study were Europid (n = 49), Japanese (n = 16), Thai (n = 7), Korean (n = 21), and Chinese (n = 13) persons with IDDM with a duration ranging from 5 to 14 years. There were similar numbers of healthy controls matched for each ethnic group. A validated radioimmunoprecipitation assay used GAD from pig brain radiolabeled with 125I using chloramine T. Islet cell cytoplasmic antibodies measured by indirect immunofluorescence were expressed as Juvenile Diabetes Foundation units. The prevalence of antibodies to GAD, compared with Europids (63%), was much lower in all Asian populations with IDDM: Japanese (31%), Thai (29%), Korean (5%), and Chinese (27%). The mean level of antibodies to GAD, however, among diabetics from each population who gave a positive reaction, was similar. For all groups, the prevalence of antibodies to GAD was much higher than that of islet cell cytoplasmic antibodies. Almost all IDDM subjects positive for islet cell antibodies had antibodies to GAD, but the converse did not hold. A radioimmunoprecipitation assay for antibodies to GAD applied to serum from subjects with IDDM in various ethnic groups showed that Europids with IDDM had a much higher prevalence of such antibodies than did Asians. This held for all ethnic groups, and particularly Koreans. Thus, among different populations, there may be etiologic heterogeneity of IDDM.(ABSTRACT TRUNCATED AT 250 WORDS)

Islet-cell antibodies and endogenous insulin secretion in Sudanese diabetic children

Cytoplasmic islet-cell antibodies (ICA) and endogenous insulin secretion were studied in 46 Sudanese children (mean age 11.6 years) with newly diagnosed insulin-dependent diabetes mellitus (IDDM). Islet-cell antibodies were detected both by the indirect immunofluorescence (IF) and complement fixation (CF) methods. Endogenous insulin levels were measured as C-peptide concentration using radio-immunoassays. The degree of metabolic control of diabetics was judged by the presence of diabetic ketoacidosis (DKA) at onset, glycated haemoglobin (HbA1c) level and insulin requirement, expressed as dose per kg body weight per day, at the time of presentation. Twenty-nine patients (63%) had either IF-ICA or CF-ICA or both in their sera. These figures are significantly higher than those reported for African populations. Islet-cell antibody positive patients had significantly lower C-peptide concentration, higher HbA1c level, higher insulin requirement and higher prevalence of ketoacidosis at presentation. Furthermore, the C-peptide levels were higher in CF-ICA positive patients than in subjects who showed only IF-ICA positivity. Our findings show a clear association between ICA and severity of diabetes at clinical onset and also suggest that the presence of CF-ICA at or shortly after diagnosis of IDDM is indicative of preservation of some functioning beta-cell mass.

Islet cell antibodies and other markers of autoimmunity and diabetes mellitus in Nauruans

Among the population of Nauru there is a high prevalence of diabetes with onset in early adult life. To ascertain whether autoimmunity to islet cell antigens contributes to this diabetes, a population survey of serum autoantibodies was performed. Subjects were grouped into euglycaemic control subjects, those with impaired glucose tolerance, and those with diabetes subdivided according to duration of disease. No subject was positive by immunofluorescence for islet cell autoantibodies. Various other autoantibodies to nuclear, thyroid and gastric autoantigens were detectable, at comparable frequencies in the three groups. This population study on Nauruan subjects selected to include those in the early phases of disease negates a contribution from islet cell autoimmunity, and thus supports the concept that the disease is the Type 2 (non-insulin-dependent) type.