Latent autoimmune diabetes in adults in a population-based cohort of Polish patients with newly diagnosed diabetes mellitus.

INTRODUCTION: Latent autoimmune diabetes in adults (LADA) is a slowly developing form of autoimmune diabetes characterized by the presence of type 1 diabetes-associated autoantibody. The aim of this study was to determine the incidence and characteristics of LADA in a population-based cohort of Polish patients with newly-diagnosed diabetes.

MATERIAL AND METHODS: The study cohort was taken from the resident population of the city Białystok, Poland, during the period 1 January to 31 December 2003, aged 20-64 years. During this period we identified 231 cases of diabetes. We measured glutamic acid decarboxylase (GADA) and insulin antibody (IAA), insulin, C peptide and glycated hemoglobin (HbA(1c)). Diagnosis of LADA was made according to Immunology Diabetes Society and Action LADA criteria.

RESULTS: The incidence of LADA was 10 per year per 100 000 people. The proportion of patients with LADA was 8.9% among newly diagnosed cases with diabetes. Patients with LADA were younger at diagnosis (48.5 ±9.4 years vs. 54.8 ±10.6 years, p < 0.01), had lower body mass index (26.9 ±9.3 kg/m(2) vs. 29.5 ±5.2 kg/m(2), p < 0.05), C peptide (126 ±127 pmol/l vs. 446 ±592 pmol/l, p < 0.001), and were less insulin resistant (HOMA IR 0.94 ±0.85 vs. 3.6±4.4, p < 0.001) compared to patients with type 2 diabetes. Glycated hemoglobin and fasting glucose were similar in patients with LADA and type 2 diabetes.

CONCLUSIONS: In addition to GAD, anti-insulin antibodies are useful for diagnosing autoimmune diabetes in adults. Patients with LADA have similar glucose control parameters (HbA(1c)) compared to patients with type 2 diabetes, although they are usually younger and have a lower body mass index. Patients with LADA make up a significant proportion of newly diagnosed people with diabetes mellitus in a Polish population.