Research Article

Type 1 diabetes risk and autoantibody positivity in Sardinian migrants in the province of Pavia

Maria T. Tenconi*, Gabriele Devoti§, Maria Rizzo*, Federico Roncarolo*, Andrea Bernasconi*, Niccolò Lanati*, Valeria Calcaterra#, Marco Songini°, Mattia Locatelli°°, Gian F. Bottazzo°°.

*Department of Preventive Medicine, University of Pavia, Viale Forlanini 2, 27100 Pavia (PV), Italy. §Department of Social Sciences and Communication, University of Lecce, Lecce, Italy. #Department of Pediatrics, University of Pavia and Foundation IRCCS Policlinico San Matteo, Pavia, Italy. °Centre for Diabetes & Metabolic Diseases, Department of Internal Medicine, S. Michele Hospital, Cagliari, Italy. °°Scientific Directorate, Bambino Gesù Pediatric Hospital, Scientific Institute, Rome, Italy.

Background: Type 1 diabetes is an autoimmune disease. Genetics as well as environmental factors seem to play a role in the pathogenesis of type 1 diabetes. Aims: We sought to investigate the possible relationship between migration from Sardinia to a low incidence area of type 1 diabetes (Lombardy) and the prevalence of autoantibody positivity. Methods: We enrolled 554 Sardinian immigrants and 226 offspring. All subjects underwent a complete anamnestic evaluation. Fasting blood glucose, HbA1c, GADA and IA-2 were measured in all study participants. Additionally, the presence of risk haplotypes (HLA-DR3 –DR4 and DQB1/0302) was determined. After seven-year follow-up, high genetic risk and/or autoantibody positivity subjects were re-evaluated. Results: Among Sardinian immigrants, prevalence of type 1 diabetes was 0.9%, while in the offspring group was 0.4%. After removing type 1 diabetic patients, GADA prevalence was 2.4% in the immigrant group and 3.8% among offspring. Among Sardinian migrants, IA-2 prevalence was 0.7%, while all offspring were IA-2 negative. After seven-year follow-up, 85.7% of GADA positive migrants had persistent GADA positivity. Two GADA negative offspring subjects turned positive. None of the study participants developed diabetes during follow-up. Conclusions: The present study showed a higher prevalence of GADA positivity within Sardinian immigrants at high genetic risk: GADA positivity may represent the first detectable phase of type 1 diabetes. After a 7 year follow-up, none of the high genetic/antibody risk group subjects developed type 1 diabetes. However, it seems reasonable to strictly control high-risk individuals in order to diagnose subclinical diabetes. (Tenconi MT, Devoti G, Rizzo M, Federico Roncarolo F, Bernasconi A, Lanati N, Calcaterra V, Songini M, Locatelli M, Gian F. Bottazzo Type 11 diabetes risk and autoantibody positivity in Sardinian migrants in the province of Pavia. North Am J Med Sci 2009; 1: 48-53)

KEY WORDS: Type 1 diabetes; Autoimmunity; Autoantibodies; Immigration.

Correspondence to: M.T. Tenconi, Department of Preventive Medicine, University of Pavia, Viale Forlanini 2, 27100 Pavia (PV), Italy, telephone number +39.0382.987278, fax +39.0382.526388 , e-mail: tenconi@unipv.it