Marco Songini on behalf of the Sardinian IDDM Study Groups The Type 1 Diabetes

1. Marco Songini on behalf of the Sardinian IDDM Study Groups The Type 1 Diabetes Sardinia (Hot&Cold Spot) Project: what did we learn so far?

2. Dr. Marco Songini is the director of the Diabetes Unit at the S. Michele Hospital in Cagliari (Sardinia- Italy) He is also the vice-president of ASRIS (Association for the Study of Type 1 Diabetes in Sardinia)

3. The island of Sardina has the second highest incidence of type 1 diabetes in the world and a high prevalence of other autoimmune diseases (celiac disease, thyroid autoimmune diseases) has been reported. The type 1 diabetes prevalence has rapidly increased after the second world war. The island also offers a relatively small population with a homogenous genetic background selected by centuries of isolation.

4. Immune markes of type 1 diabetes (ICA, GADA, IA2, IAA) appear several years before the clinical onset of the disease, as was seen in family members of diabetic patients, but relatively little is know about the prevalence and prognosis of such markers in the general population. The aim of the Hot and Cold Spot Project is to investigate the prevalence of immune markers in Sardinian population and to evaluate their prognostic significance to develop a screening procedure.

5. History of the Hot&Cold Spot Project (1) ending of the recruitment of the SSI (total cohort  10,000 children) 1995 first recruitment of newborn from the general population: launch of the Sardinian Newborn IDDM study (SNI) 1994 the Military Service approach (secular trend of type 1 diabetes among Sardinians) 1993 ICA assay in 1,800 serum samples of school children from the general population enrolled for an epidemiological study of goitre prevalence in Sardinia; first milestone of the Sardinian School children IDDM Study (SSI) 1990 1989 Eurodiab - Ace: Sardinia is an ‘hot spot’ for Type 1 diabetes in Europe

6. History of the Hot&Cold Spot Project (2) 1999 HLA typing in ‘immunologically at risk’ children for type 1 diabetes the Post-partum Thyroiditis and Neonatal Hypothyiroidism studies 1998 the Gestational Diabetes (GDM) Study 1998 Coeliac Disease in the Northern Sardinia school children 1997 The Sardinian Migrants IDDM study (SMI) in the province of Pavia 1997 stop of recruitment of SNI (total cohort  19,000 children) 1997 1996 The Environmental / Veterinarian / Ecological studies - first results

7. Time trends in Type 1 Diabetes incidence ( 0 - 14 years) 45 Finland (40) 40 Sardinia (35) 35 30 Sweden (25.8) 25 Incidence (per 100,000) Norway (21.2) 20 Denmark (16.4) 15 10 Hungary (8.8) 5 0 1960 1965 1970 1975 1980 1985 1990 1994 Calendar year

8. The Sardinian Schoolchildren IDDM Study (SSI) (1) Survival Function 1,0 ,9 Number of Abs ,8 ,7 3 Cum Survival 2 ,6 1 0 ,5 0 20 40 60 80 100 LATENCY (months)

9. Oristano 45/100,000/year Cagliari 38/100,000/year Nuoro 35/100,000/year Sassari 30/100,000/year The Sardinian Schoolchildren IDDM Study (SSI) (2) % 10 9 8 7 6 5 4 3 2 1 0 >= 2 Abs 1 Ab

10. The Sardinian Newborn-IDDM Study (SNI) (1) 18 Centres from the 4 Sardinian provinces involved in the Study Number recruited ~ 19,000 ICA tested = 15,509 (cord blood) ICA JDF-u 2.3% ICA 6-19 JDF-u 1.7% ICA JDF-u 0.6%

11. The Sardinian Newborn-IDDM Study (SNI) (2) FOLLOW UP % 2.0 1.6 prevalence 1.2 0.8 0.4 0.0 2,959 2,125 2,117 1,148 399 399 388 1st YEAR 2nd YEAR 3rd YEAR ICA JDF-u GADA  IA-2icA 

12. P r e v a l e n c e o f i s l e t - r e l a t e d a u t o a n t i b o d i e s (ICA, GADA and IA - 2icA) according to the different age (from the S a r d i n i a n N e w b o r n and the S a r d i n i a n S c h o o l C h i l d r e n S t u d i e s) 7 % 6 5 prevalence 4 3 2 1 0 cord blood 1 2 3 6 7 8 9 10 11 12 13 14 15 age (years) ICA JDF-u GADA  IA-2icA 10

13. The COELIAC DISEASE study (1) ~ 1,600 Sardinian school children investigated for AGA-IgG, AGA-IgA and AEA Prevalence of coeliac disease (confirmed by intestinal biopsy) 10.5/1000 children the highest reported so far in a background population

14. Coeliac Disease and pre -Type 1 Diabetes in Sardinian schoolchildren (2) Islet-related Abs CD-related Abs 11* 126 79 * ICA + IgG-AGA = 8 GADA + IgG-AGA = 1 GADA + IgG/IgA-AGA + AEA = 2

15. The MILITARY SERVICE approach Secular trend of type 1 diabetes prevalence at 19 years among male conscripts in Sardinia 7,00 6,00 5,00 4,00 Prevalence (per 1000) 3,00 2,00 1,00 0,00 1936 1940 1944 1950 1954 1958 1962 1964 1966 1968 1972 1976 1938 1942 1946 1948 1952 1956 1960 1970 1974 1978 Birth cohorts

16. The ENVIRONMENTAL and ECHOLOGICAL studies Birth seasonality Onset seasonality Temp, pop. density, urban/rural Average rainfall Time- and space-clustering overlap with: - malaria - talassemia - G-6-P-D deficiency Nitrate intake (bottle and tap waters) Cow’s and breast milk feeding YES YES NO NO YES NO NO NO NO NO

17. The GESTATIONAL DIABETES (GDM) Study ~ 100 Sardinian mothers with GDM investigated for ICA, GADA and IA-2icA 8 women resulted positive for at least 1 islet-related autoantibody at the time of OGTT After a follow up of 4 yrs, 5 became diabetic (3 insulin-dependent and 2 non insulin-dependent)

18. 6 5 ATA pos (%) 4 Males 3 Females 2 1 0 6-7 7-8 8-9 9-10 10-11 11-12 12-13 13-14 >14 Age (years) AUTOIMMUNE THYROIDITIS in Sardinian school children (1) ~ 8,000 Sardinian schoolchildren from the general population investigated for ATA Overall, the prevalence of ATA was 3.7% and the prevalence of a subclinical thyroiditis was about 0.9% No correlations were found between prevalence of ATA and urinary iodine excretion or prevalence of goitre

19. ATA and ICA in Sardinian school children (2) ICA + 325 ATA + 211 16

20. 40 35 100 30 80 25 60 20 15 40 10 20 5 0 0 OR CA NU SS ATA at low titers ICA*  20 JDFu ICA 5-19 JDFu ICA < 5 JDFu ATA at high titers AUTOIMMUNE THYROIDITIS and PREGNANCY (3) ~ 2,500 Sardinian mothers at delivery time were investigated for ATA and ICA At the time of delivery, the prevalence of ATA and ICA was 11.8 and 2.6%, respectively (0.4% with both specificities) Prevalence of ATA (%)

21. The SARDINIAN MIGRANTS study the prevalence of type 1 diabetes was assessed in ~ 2,200 born in Sardinia and migrated to Pavia In 10 individuals the diagnosis of T1D has been confirmed giving a prevalence (4/1000) similar to that registered in the island and 3 times higher than the ones registered in Northern Italy. 3 subjects were already diabetic at the time of migration, and 7 developed the disease after the migration to Pavia. 35 30 25 20 Age at onset of T1D (years) 15 10 5 0 Before migration (Nr=3) After migration (Nr=7)

22. What did we learn so far? (1) Islet-related autoantibodies can appear very early in life (with particular reference to GADA) and they play a predictive role towards the future onset of type 1 diabetes. The appearance of islet-related autoantibodies progressively increases in the first years of life. The combination of more than 1 islet-related autoantibody (rather than which autoantibody) is the best predictor for the development of type 1 diabetes in the Sardinian school children population.

23. What did we learn so far? (2) Even though some epidemiological evidences suggest a role of the environment on the etiopathogenesis of type 1 diabetes, none of the variables considered so far have shown their influence; however other variables need to be further investigated. Coeliac disease shows an high prevalence among Sardinian school children and then it deserves more large investigations. It seems not to play a relevant role on the etiopathogenesis of type 1 diabetes in Sardinia instead.

24. What did we learn so far? (3) The prevalence of thyroid-related autoantibodies seems not to be as much as high among Sardinian school children, even though they live in an Island at high risk for other autoimmune diseases. The same findings appear among the pregnant mothers, in whom the prevalence of ATA is not significantly higher than the ones registered in other matched populations. However, the possible immunosuppressive role of pregnancy on these parameters needs to be further investigated.

25. What we are doing now (1) Trying to further improve the prediction of type 1 diabetes in the general population by carrying out HLA genetic typing in children found ‘at immunological risk’ during the screening. Studying the immunological and genetic markers for type 1 diabetes and other autoimmune diseases in Sardinian migrants and their relatives. Investigating other putative environmental factors which can play a role towards the etiopathogenesis of type 1 diabetes (e.g., chemicals, toxins, vaccinations, viral infections, etc.).

26. What we are doing now (2) Broadening the original investigation for type 1 diabetes on the prevalence of coeliac disease and autoimmune thyroid diseases and to study their associations. Comparing data from Sardinia and other areas (continental Italy, Finland, Sweden, Spain) by new collaborative studies. Investigating LADA within the Sardinian type 2 patients.

27. $ 250,000 20 225,000 18 200,000 16 175,000 cost saved 14 150,000 12 years 125,000 10 cost saved cost saved 100,000 8 75,000 6 50,000 4 25,000 2 0 0 Cost of predicting T1-DM from birth andin school children background population 1 2 3 modified from Hahl et al. Diabetologia (1998) 41:79-85 4

28. 1. Early diagnosis / Early insulin treatment (In U.S.A. about 50 deaths yearly from DKA) 2. ? Prevention and/or delay of diabetic complications 3. Prevention of the onset of type 1 diabetes in ‘at risk’ individuals (? magic bullet) 4. Identification of ‘non at-risk’ individuals (>99%) Benefits of a predictive screening for Type 1 diabetes in the general population

29. In spite of Gian Franco’s breakthrough twenty-five years ago with the ICA, the mystery of Type 1 diabetes still remains deeply hidden ... ? ? ? ? ? ? ? ? … but we strongly believe that along with him in this beautiful Island, we have a very good chance to unravel the causes of the autoimmune diseases. ? ? ? ? The IDDM-Sardinia Study Groups