Barbara Szepietowska, Anna Głębocka, Urszula Puch, Maria Górska, Małgorzata Szelachowska The prevalence of LADA among type 2 diabetics in a large cohort of European individuals aged 25 to 65 years in the United Kingdom Prospective Dia- betes study (UKPDS) was 10% [2]. In Finish and Swedish individuals with type 2 diabetes, the preva- lence was 9% and 8%, respectively [3, 4]. The inci- dence of LADA in Wales was calculated to be 9 cases per 100 000 inhabitants, per year [5]. Iden- tification of patients with LADA has important clin- ical implications, because these individuals require therapeutic intervention adjusted for the progres- sive decline of β cell function [6-8]. We used the immunological marker anti-glu- tamic acid decarboxylase antibody (GADA) to iden- tify LADA as this is the common standard used to identify patients with LADA. The GADA persists after diagnosis, and unlike ICA, commercial available assays can be used for measurements [9, 10]. In this study we investigated patients with new onset diabetes and used an additional marker, anti-insulin antibody (IAA), to identify those with LADA. Anti-insulin antibody were first identified in the .. sera of newly diagnosed insulin-naIve patients with type 1 diabetes by Palmer et al. [11]. Anti-insulin antibody has now been demonstrated as an autoimmune marker for prediction and diagnosis of type 1 diabetes [12, 13]. According to the Immunology of Diabetes Society, IAA can also be used to identify patients with LADA [1]. In a large Chinese population, IAA was found to be present (3.39%) in phenotypic type 2 diabetes patients and, in combination with GADA, significantly increased the number of patients diagnosed with LADA [14]. The aim of this study was to determine the inci- dence and characteristics of LADA in a population- based cohort of Polish patients with newly-diag- nosed diabetes and determine whether anti-insulin antibody may be useful in identifying patients with LADA. Material and methods Participants The study protocol was approved by the Ethics Committee of the Medical University of Bialystok. Informed consent was obtained from all patients before blood sampling. Diabetes was diagnosed according to the World Health Organization (WHO) 1999 criteria. The study base was the resident pop- ulation of the city Bialystok, Poland, aged 20 to 64 years during the period 1 January 2003 to 31 Decem- ber 2003 (291 931 inhabitants, 188 738 aged 20-65 years). All cases of diabetes arising during the study period were identified through primary care physi- cians or primary care physicians and diabetologists working in the public health clinic. All patients were Polish citizens and, irrespective of their social sta- tus or employment, were cared for by a general practitioner as part of the National Health System. Primary care for diabetic patients is mainly provid- ed by specialized diabetes clinics. All diabetic patients can obtain drugs and diabetes devices free of charge from the National Health System, pro- vided they have certification of diabetes diagnosed. For the above-mentioned reasons, almost all new- ly diagnosed patients are attended by a primary care physician from the National Health System or diabetes clinic at the onset of the disease. Dia- betologists and primary care physicians were peri- odically contacted by the coordinating centre. The coordinating center was the Department of Inter- nal Medicine, Diabetology and Endocrinology, locat- ed in the Teaching Hospital of the Medical Univer- sity of Bialystok. In 2003 and 2004, the clinical charts of all diabetes patients in the area of inter- est were reviewed to identify cases that had not been reported to the coordinating center and to assess clinical features of the individuals who had not been tested. Data collection Recruited participants arrived at the research unit for data collection after an overnight fast. Blood samples for biochemical and immunological analy- sis were obtained prior to the morning insulin or oral therapy. Detailed demographic data and clini- cal and treatment history were recorded using an interviewer-administered questionnaire. The data were verified using medical records. Anthropomet- ric measurements were recorded according to the standard methods. Blood sampling was performed following diagnosis and stored at –20°C for future analysis. Laboratory measurements Fasting plasma glucose was measured immedi- ately by the enzymatic method using a glucose analyser. Total plasma cholesterol, HDL cholesterol and triglycerides were evaluated by the enzymatic method (Cormay, Poland); LDL cholesterol was cal- culated using Friedewald’s formula. Glycated hemo- globin (HbA1c) was assessed by the high perform- ance liquid chromatography method (Bio-Rad, Germany). Plasma insulin was measured with the Medgenix EASIA test (Biosource Europe, Belgium). The minimum detectable concentration was 1.05 pg/l. In this method, human and animal proinsulin exhibits no cross-reactivity. C-peptide concentra- tion was measured using an immunoenzymatic assay (Biosource Europe, Belgium) (specificity: 88%, human proinsulin – 12.5%, sensitivity: 0.01 pmol/ml; intra-assay CV: 5.8%). GADA and IAA were meas- ured by commercially available RIA sets (CIS bio international, France). Anti-glutamic acid decar- boxylase antibody was considered positive with 492 Arch Med Sci 3, June / 2012