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

Abstract

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 versus 9% in healthy controls (24% versus 7% for GADA (p < 0.001), 10% versus 3% for IA-2A (p < 0.006); 4% versus 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 versus 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.

Type 1 Diabetes in a Resource-Poor Setting: Malnutrition Related, Malnutrition Modified, or Just Diabetes?

“…1 which shows the age of presentation of a consecutive series of over 2280 diabetic patients over a 14-year period; nearly a half of the patients had T1DM. There were similar findings in a third culturally distinct area of Ethiopia, Mekelle [ 6 ], South Africa [ 7 ] and Cameroon [ 8 ]. By contrast, the pattern of disease reported from diabetes registries in the West show a much higher incidence rate in the under-15 age group (50–60%) with peak incidence at or before puberty [ 9 ].…”

“…Autoimmunity is believed to be a very important factor in the aetiology of T1DM, especially that arising in childhood. Recent studies have reported rates of islet autoantibody positivity ranging from 30% in Tanzania [ 23 ], 29–35% in Ethiopia [ 24 •, 25 ] to 43% in Cameroon [ 8 ] in T1DM. These studies have been carried out for the most part in adult patients and some in mainly urban areas.…”

“…These results suggest that, even when using age-appropriate comparisons, the proportion of diabetes resulting from autoimmunity in sub-Saharan Africa may be lower than in the European population. Recent reports from Cameroon [ 8 ], Tunisia [ 29 ] and Egypt [ 30 ] have drawn attention to the influence of HLA status on autoantibody production in T1DM in these countries. In regions where there are lower frequencies of diabetes-associated HLA haplotypes, there may be fewer cases of diabetes with an autoimmune basis, although this is unlikely to be the only factor.…”

Type 1 diabetes in Africa: an immunogenetic study in the Amhara of North-West Ethiopia

“…A recent study of type 1 diabetes from West Africa (Cameroon) investigated an urban group shortly after clinical diagnosis and compared them with a Belgian population. As in Ethiopia, few (9%) had childhood-onset type 1 diabetes, and in those who were classified as having type 1 diabetes a very low percentage of children (≤15 years) and adults (median age 30 years) were autoantibody positive; the majority of these had GADA, and far fewer had IA-2A or ZnT8A [2]: the overall autoantibody prevalence in those classified as having type 1 diabetes was lower than in the Amhara. The adult Belgian diabetic participants had a much higher incidence of multiple autoantibodies than the Cameroonian participants.…”

“…There is wide genetic diversity in sub-Saharan Africa; that being the case, we have studied a single ethnic group to limit genetic diversity within this study and have emphasised that the results from the Semitic-background Amhara differ in autoantibody profile from the Bantu-background Cameroonians [2], who were investigated at a similar time, close to clinical diagnosis. Additionally, both the Amhara and Bantu have shown some differences from European background groups.…”