Abstract:
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.
