Frequency of diabetes and thyroid autoantibodies in patients with autoimmune endocrine disease from Cameroon

Diabetes is a major cause of morbidity and mortality in both industrialized and developing countries. In Africa, there are little data on the prevalence and immunological features of patients with autoimmune endocrine diseases.

The present hospital-based study was carried out to evaluate disease-associated autoantibodies in both type 1 diabetes and thyrotoxicosis attending the Central Hospital of Yaoundee in Cameroon.

Samples were collected from a total of 101 subjects, 47 of whom clinically had established type 1 diabetes (mean age 30.1 years +/- 7.6, mean disease duration 3.3 years), 18 had thyrotoxicosis (mean age 32.7 years +/- 7.6, mean disease duration 6.3 years +/- 2.8) and 36 normal subjects (mean age 26 years +/- 4.5). All subjects were tested for diabetes-associated glutamic acid decarboxylase (GAD) and tyrosine phosphatase (IA2) autoantibodies using antigen-specific radioimmunoassay as well as thyroiditis-associated thyroglobulin (Tg) and thyroid peroxidase (TPO) autoantibodies using commercially available kits.

Of 47 patients with type 1 diabetes, 16 (34%) had GAD autoantibodies (Abs), 3 (6.4%) had IA2 Abs, and 2 (4.3%) had TPO Abs. Of 18 patients with thyrotoxicosis 4 (22.2%) had GAD Abs, 5 (27.8%) showed IA2 Abs, while 8 patients (44.4%) were TPO Abs positive. No patients in either group had Tg Abs. Among normal subjects, 2 (5.6%) showed GAD Abs, and one of these was also IA2 Abs positive, but none had thyroid autoantibodies.

Adult-onset type 1 diabetic patients some years post-diagnosis from central Africa show GAD, IA2 or TPO Abs; and surprisingly, patients with thyrotoxicosis had a similar frequency of diabetes-associated autoantibodies. We conclude that, despite a different genetic and environmental background to European populations, islet cell autoimmunity is common in autoimmune endocrine patients in central Africa.