Title:Global epidemiology of Type 1 diabetes in young adults and adults. A Systematic Review

Author's response to reviews Title:Global epidemiology of Type 1 diabetes in young adults and adults. A Systematic Review Authors: Paula A Diaz-Valencia (paula.diaz@inserm.fr) Pierre Bougnères (pierre.bougneres@inserm.fr) Alain-Jacques Valleron (alain-jacques.valleron@inserm.fr) Version:3Date:7 February 2015 Author's response to reviews: see over

Response to Reviewers Ms Ma. Celine Zapanta on behalf of Dr. Charumathi Sabanayagam Academic Editor BMC Public Health BioMed Central Floor 6, 236 Gray's Inn Road London WC1X 8HB United Kingdom Paris, February 7 th 2015 Dear Dr Sabanayagam: We are pleased to submit on the BioMed Central website of BMC Public Health the revised version of our manuscript: 1900671941518901; research article, entitled: Global epidemiology of Type 1 diabetes in young adults and adults. A Systematic Review We thank you for your most helpful comments, which we addressed as outlined in following attached file. We hope that you will find this revised version suitable for publication. Thank you in advance for your consideration; we look forward to hearing from you. Sincerely yours, Paula A. Diaz-Valencia, Pierre Bougnères, Alain-Jacques Valleron Inserm Unité 1169 Site de l'hôpital de Bicêtre. Bâtiment Grégory Pincus - 80, rue du Général Leclerc. 94276 Le Kremlin Bicêtre. France Tel: +33 01 49 59 53 45 e-mail: paula.diaz@inserm.fr, paulaandreadiaz@gmail.com

MS: 1900671941518901 Research article Global epidemiology of Type 1 diabetes in young adults and adults. A Systematic Review Paula A Diaz-Valencia, Pierre Bougnères and Alain-Jacques Valleron BMC Public Health ANSWER TO THE REVIEWER: RYTAS OSTRAUSKAS Major Compulsory Revisions: 1. Very interesting topic, but very strange method of working and of presentation. Data about adulthood onset type 1 diabetes in not so much and I don't understand why you snub a part of them. It is true that in the previous version of the paper, we only presented the papers that we used in the statistical analyses. Therefore our list of 47 papers could not be read as giving the full list of published papers on adult T1D. There were 12 papers that we found, but did not show, for example the first of two papers concerning the same region or country (in this case, we only included the last one). For the new version of the MS in addition, we examined cited references of all retrieved papers in Google scholar. In the new version of the paper, we now show all the papers retrieved in the main text (see Table 1: Systematic review of type 1 diabetes in adults, diagnostic criteria and sources of information ). They are 70 papers (71 studies), 23 more than in the previous version: the 12 that were excluded from the analysis, and 11 new papers. They are: Country, Area First Author, publication year Ref Australia: New South Wales Tran F, 2014 [1] Belgium, Antwerp Vandewalle C, 1997 [2] Belgium, Antwerp Weets I, 2002 [3] France: Aquitaine, Lorraine, Charkaluk M L, 2002 [4] Basse Normandie, Haute Normandie Israel: NW Blumenfeld O, 2014 [5] Israel: NW Sella T, 2011 [6] Italy, Lombardie Garancini G, 1991 [7] Italy: Sardinia Muntoni S, 1992 [8] Italy: Turin Bruno G, 1993 [9] Lithuania, Nationwide Ostrauskas R, 2000 [10] Lithuania, Nationwide Pundziute-Lycka A, 2003 [11] Poland: Province of Rzeszow Sobel-Maruniak A, 2006 [12] Spain: Catalonia Goday A. 1992 [13] Spain: Navarra Forga L, 2014 [14] Sweden, Nationwide Blohme G, 1992 [15] Sweden, Nationwide Pundziute-Lycka A, 2002 [16] Sweden, Nationwide Östman J, 2008 [17] Sweden, Nationwide Nyström L, 1992 [18] United Kingdom: Oxford Bingley P J, 1989 [19] region United States of America: Wagenknecht L E, 1989 [20] Alabama (Jefferson County) United States of America: Colorado Kostraba J.N, 1992 [21]

United States of America: The United States Navy Gorham C, 1993 [22] US Virgin Islands: NW Washington RE, 2013 [23] Note: The Additional file 1: Search equation used for the bibliographic analysis and Figure 1: PRISMA Flow diagram bibliographic search strategies were updated to include the new references, and simplified. 2. Authors who describe children's diabetes, find better methods of data presentation. I wish you success for summarizing more data. In the previous version of the paper, we probably were wrong to split the information as we did between the main MS and the Additional data files. In the new MS we present a summary of all retrieved information in Table 1 of the paper: Systematic review of type 1 diabetes in adults, diagnostic criteria and sources of information of the main MS with the classical presentation of incidence data: country/area, first author, year of publication, age group reporting incidence, diagnostic criteria used to define T1D, sources of information, and % of ascertainment. Incidence level by age class can be found in Additional File 4_Table 1, and the specific information on sex differences in Additional File 5_ Table 2). Minor Essential Revisions: 3. Data should be compared not only by the countries but also in periods of time. In our SR, we found information on incidence of T1D in people aged >30 years of age of different periods of time only for Belgium (Antwerp), Lithuania and Sweden. In the discussion, we stress in the discussion that very sparce data were available to document a possible trend in adult T1D incidence. In main text lines 224:228 The paucity of data made it impossible to document an increase in adult T1D incidence that would parallel the dramatic increase observed in children [24-26]. Indeed, successive studies in the same region over different periods reporting incidence in people aged >30 years of age were only found for Belgium [2, 3, 27], Lithuania [10, 11, 28] and Sweden [15-18, 29]. 4. It is not clear whether the incidence data differ by geographic location or by different data periods. As mentioned above, a quantitative analysis of the possible trend in adult T1D incidence is not feasible. However it can be noticed that the correlation described in Figure 3 Geographical covariation between 0-14 T1D incidence and adult T1D incidence between children and adults was based on studies all collected during approximately the same period (1980-1990).

5. Manuscript submitted online, so it can be longer and wider. Following the reviewer s advice, our MS now includes more information, in particular a table giving the details of all retrieved information (Table 1 Systematic review of type 1 diabetes in adults, diagnostic criteria and sources of information ). Quality of written English: Needs some language corrections before being published A senior researcher, and native English speaker edited the final version of our MS. References: 1. Tran F, Stone M, Huang CY, Lloyd M, Woodhead HJ, Elliott KD, Crock PA, Howard NJ, Craig ME: Population-based incidence of diabetes in Australian youth aged 10-18 yr: increase in type 1 diabetes but not type 2 diabetes. Pediatric diabetes 2014, 15(8):585-590. 2. Vandewalle CL, Coeckelberghs MI, De Leeuw IH, Du Caju MV, Schuit FC, Pipeleers DG, Gorus FK: Epidemiology, clinical aspects, and biology of IDDM patients under age 40 years. Comparison of data from Antwerp with complete ascertainment with data from Belgium with 40% ascertainment. The Belgian Diabetes Registry. Diabetes care 1997, 20(10):1556-1561. 3. Weets I, De Leeuw IH, Du Caju MV, Rooman R, Keymeulen B, Mathieu C, Rottiers R, Daubresse JC, Rocour-Brumioul D, Pipeleers DG et al: The incidence of type 1 diabetes in the age group 0-39 years has not increased in Antwerp (Belgium) between 1989 and 2000: evidence for earlier disease manifestation. Diabetes care 2002, 25(5):840-846. 4. Charkaluk ML, Czernichow P, Levy-Marchal C: Incidence data of childhood-onset type I diabetes in France during 1988-1997: the case for a shift toward younger age at onset. Pediatr Res 2002, 52(6):859-862. 5. Blumenfeld O, Dichtiar R, Shohat T, Israel IRSG: Trends in the incidence of type 1 diabetes among Jews and Arabs in Israel. Pediatric diabetes 2014, 15(6):422-427. 6. Sella T, Shoshan A, Goren I, Shalev V, Blumenfeld O, Laron Z, Chodick G: A retrospective study of the incidence of diagnosed Type 1 diabetes among children and adolescents in a large health organization in Israel, 2000-2008. Diabetic medicine : a journal of the British Diabetic Association 2011, 28(1):48-53. 7. Garancini P, Gallus G, Calori G, Formigaro F, Micossi P: Incidence and prevalence rates of diabetes mellitus in Italy from routine data: a methodological assessment. European journal of epidemiology 1991, 7(1):55-63. 8. Muntoni S, Songini M: High incidence rate of IDDM in Sardinia. Sardinian Collaborative Group for Epidemiology of IDDM. Diabetes care 1992, 15(10):1317-1322.

9. Bruno G, Merletti F, Vuolo A, Pisu E, Giorio M, Pagano G: Sex differences in incidence of IDDM in age-group 15-29 yr. Higher risk in males in Province of Turin, Italy. Diabetes care 1993, 16(1):133-136. 10. Ostrauskas R, Zalinkevicius R: Incidence in young adulthood-onset Type 1 diabetes mellitus in Lithuania during 1991-1997. Lithuanian Epidemiology Diabetes Study Group. Diabetes, nutrition & metabolism 2000, 13(2):68-74. 11. Pundziute-Lycka A, Urbonaite B, Ostrauskas R, Zalinkevicius R, Dahlquist GG: Incidence of type 1 diabetes in Lithuanians aged 0-39 years varies by the urban-rural setting, and the time change differs for men and women during 1991-2000. Diabetes care 2003, 26(3):671-676. 12. Sobel-Maruniak A, Grzywa M, Orlowska-Florek R, Staniszewski A: The rising incidence of type 1 diabetes in south-eastern Poland. A study of the 0-29 yearold age group, 1980-1999. Endokrynol Pol 2006, 57(2):127-130. 13. Goday A, Castell C, Tresserras R, Canela J, Taberner JL, Lloveras G: Incidence of type 1 (insulin-dependent) diabetes mellitus in Catalonia, Spain. The Catalan Epidemiology Diabetes Study Group. Diabetologia 1992, 35(3):267-271. 14. Forga L, Goni MJ, Ibanez B, Cambra K, Mozas D, Chueca M: [Incidence of type 1 diabetes in Navarre, 2009-2012]. Anales del sistema sanitario de Navarra 2014, 37(2):241-247. 15. Blohme G, Nystrom L, Arnqvist HJ, Lithner F, Littorin B, Olsson PO, Schersten B, Wibell L, Ostman J: Male predominance of type 1 (insulin-dependent) diabetes mellitus in young adults: results from a 5-year prospective nationwide study of the 15-34-year age group in Sweden. Diabetologia 1992, 35(1):56-62. 16. Pundziute-Lycka A, Dahlquist G, Nystrom L, Arnqvist H, Bjork E, Blohme G, Bolinder J, Eriksson JW, Sundkvist G, Ostman J: The incidence of Type I diabetes has not increased but shifted to a younger age at diagnosis in the 0-34 years group in Sweden 1983-1998. Diabetologia 2002, 45(6):783-791. 17. Ostman J, Lonnberg G, Arnqvist HJ, Blohme G, Bolinder J, Ekbom Schnell A, Eriksson JW, Gudbjornsdottir S, Sundkvist G, Nystrom L: Gender differences and temporal variation in the incidence of type 1 diabetes: results of 8012 cases in the nationwide Diabetes Incidence Study in Sweden 1983-2002. Journal of internal medicine 2008, 263(4):386-394. 18. Nystrom L, Dahlquist G, Ostman J, Wall S, Arnqvist H, Blohme G, Lithner F, Littorin B, Schersten B, Wibell L: Risk of developing insulin-dependent diabetes mellitus (IDDM) before 35 years of age: indications of climatological determinants for age at onset. Int J Epidemiol 1992, 21(2):352-358. 19. Bingley PJ, Gale EA: Incidence of insulin dependent diabetes in England: a study in the Oxford region, 1985-6. BMJ 1989, 298(6673):558-560. 20. Wagenknecht LE, Roseman JM, Alexander WJ: Epidemiology of IDDM in black and white children in Jefferson County, Alabama, 1979-1985. Diabetes 1989, 38(5):629-633. 21. Kostraba JN, Gay EC, Cai Y, Cruickshanks KJ, Rewers MJ, Klingensmith GJ, Chase HP, Hamman RF: Incidence of insulin-dependent diabetes mellitus in Colorado. Epidemiology 1992, 3(3):232-238. 22. Gorham ED, Garland FC, Barrett-Connor E, Garland CF, Wingard DL, Pugh WM: Incidence of insulin-dependent diabetes mellitus in young adults: experience

of 1,587,630 US Navy enlisted personnel. American journal of epidemiology 1993, 138(11):984-987. 23. Washington RE, Orchard TJ, Arena VC, Laporte RE, Tull ES: Incidence of type 1 and type 2 diabetes in youth in the U.S. Virgin Islands, 2001-2010. Pediatric diabetes 2013, 14(4):280-287. 24. The DIAMOND Project Group: Incidence and trends of childhood Type 1 diabetes worldwide 1990-1999. The DIAMOND project Group. Diabet Med 2006, 23(8):857-866. 25. Patterson CC, Dahlquist GG, Gyurus E, Green A, Soltesz G: Incidence trends for childhood type 1 diabetes in Europe during 1989-2003 and predicted new cases 2005-20: a multicentre prospective registration study. Lancet 2009, 373(9680):2027-2033. 26. Patterson CC, Gyurus E, Rosenbauer J, Cinek O, Neu A, Schober E, Parslow RC, Joner G, Svensson J, Castell C et al: Trends in childhood type 1 diabetes incidence in Europe during 1989-2008: evidence of non-uniformity over time in rates of increase. Diabetologia 2012, 55(8):2142-2147. 27. Weets I, Rooman R, Coeckelberghs M, De Block C, Van Gaal L, Kaufman JM, Keymeulen B, Mathieu C, Weber E, Pipeleers DG et al: The age at diagnosis of type 1 diabetes continues to decrease in Belgian boys but not in girls: a 15-year survey. Diabetes Metab Res Rev 2007, 23(8):637-643. 28. Ostrauskas R, Zalinkevicius R, Jurgeviciene N, Radzeviciene L, Lasaite L: The incidence of type 1 diabetes mellitus among 15-34 years aged Lithuanian population: 18-year incidence study based on prospective databases. BMC public health 2011, 11:813. 29. Dahlquist GG, Nystrom L, Patterson CC: Incidence of Type 1 Diabetes in Sweden Among Individuals Aged 0-34 Years, 1983-2007: An analysis of time trends. Diabetes Care 2011, 34(8):1754-1759.

MS: 1900671941518901 Research article Global epidemiology of Type 1 diabetes in young adults and adults. A Systematic Review Paula A Diaz-Valencia, Pierre Bougnères and Alain-Jacques Valleron BMC Public Health ANSWER TO THE REVIEWER: CHARUMATHI SABANAYAGAM Diaz-Valencia et al. evaluated the epidemiology of type-1 diabetes in adults worldwide using a systematic review approach. The title sounds interesting; however the review was not rigorously done. It is true that in the previous version of the paper, we only presented the papers that we used in the statistical analyses. Therefore our list of 47 papers could not be read as giving the full list of published papers on adult T1D. There were 12 papers that we found, but did not show, for example the first of two papers concerning the same region or country (in this case, we only included the last one). For the new version of the MS, in addition, we examined the cited references of all retrieved papers in Google scholar. In the new version of the paper, we now show all the papers retrieved in the main text (see Table 1: Systematic review of type 1 diabetes in adults, diagnostic criteria and sources of information ). They are 70 papers (71 studies), 23 more than in the previous version: the 12 that were excluded from the analysis, and 11 new papers. They are: Country, Area First Author, publication year Ref Australia: New South Wales Tran F, 2014 [1] Belgium, Antwerp Vandewalle C, 1997 [2] Belgium, Antwerp Weets I, 2002 [3] France: Aquitaine, Lorraine, Charkaluk M L, 2002 [4] Basse Normandie, Haute Normandie Israel: NW Blumenfeld O, 2014 [5] Israel: NW Sella T, 2011 [6] Italy, Lombardie Garancini G, 1991 [7] Italy: Sardinia Muntoni S, 1992 [8] Italy: Turin Bruno G, 1993 [9] Lithuania, Nationwide Ostrauskas R, 2000 [10] Lithuania, Nationwide Pundziute-Lycka A, 2003 [11] Poland: Province of Rzeszow Sobel-Maruniak A, 2006 [12] Spain: Catalonia Goday A. 1992 [13] Spain: Navarra Forga L, 2014 [14] Sweden, Nationwide Blohme G, 1992 [15] Sweden, Nationwide Pundziute-Lycka A, 2002 [16] Sweden, Nationwide Östman J, 2008 [17] Sweden, Nationwide Nyström L, 1992 [18] United Kingdom: Oxford Bingley P J, 1989 [19] region United States of America: Wagenknecht L E, 1989 [20] Alabama (Jefferson County) United States of America: Colorado Kostraba J.N, 1992 [21]

United States of America: The United States Navy Gorham C, 1993 [22] US Virgin Islands: NW Washington RE, 2013 [23] Note: The Additional file 1: Search equation used for the bibliographic analysis and Figure 1: PRISMA Flow diagram bibliographic search strategies were updated to include the new references, and simplified. 1. Title: As the title suggests, authors should present other epidemiological features such as risk factors, trends, differences by gender, ethnicity etc. in addition to geographic variation in incidence. The papers retrieved focus on the descriptive epidemiology of adult T1D, and do not give conclusive data on risk factors. Trends: In this MS we could not study the change in the incidence trends of T1D in young adults and adults because too little data were available. In the new MS, we explain this in the discussion (lines 224:231): The paucity of data made it impossible to document an increase in adult T1D incidence that would parallel the dramatic increase observed in children [24-26]. Indeed, successive studies in the same region over different periods reporting incidence in people aged >30 years of age were only found for Belgium [2, 3, 27], Lithuania [10, 11, 28] and Sweden [15-18, 29]. Similarly, this SR did not dispose of sufficient data to document differences in the clinical presentation of T1D of adults and children as suggested elsewhere [2, 30]; indeed only two of the 71 studies describe differences in clinical presentation of T1D between adults and children [31, 32]. Difference by gender: Thank you for the suggestion. Yes, it was possible to study this aspect and we did so. The analysis of the incidence of T1D by sex is now included in the new article, and the main result (a larger T1D incidence in men than in women) is also reported in the abstract. A table giving the detailed information is presented in the Additional File 5 Table 2. In results (main manuscript lines 189:192), we indicate: Comparison of male and female T1D adult incidences T1D incidence was larger in males aged 15 to 39 years than in females in 44 (81%) of the 54 studies reporting incidence by sex (Additional File 5 Table 2). The mean male-to-female ratio in our SR was 1.47 (95% CI for mean 1.33-1.60, SD = 0.49, n = 54, p= < 0.0001). Ethnicity: We explored this aspect in depth and considered that the available data were too sparse to be presented. For the Reviewer, the information here includes a description of the information we retrieved about ethnicity:

In Mauritius, the incidence was similar among individuals of Asian Indian, Chinese or Creole origin [33]. In Israel, a significant difference was found between Jews and Arabs [5, 30]. In Unites States, in Pennsylvania, the incidence was higher in non-whites than in Whites [34], in Alabama the opposite was found [20, 35], whereas, in Colorado non significant differences were found after exploring the incidence of T1D in different periods [36]. 2. The title mentions adults, but majority of the included studies reported the incidence among 0-14 or 15-19 years. The title could be modified to include young adults in addition to adults. We agree. We changed the title of our manuscript to: Global epidemiology of Type 1 diabetes in young adults and adults. A Systematic Review 3. Do calendar period and urban/rural area play a role in the incidence? Were there any within-country variations in the incidence? Calendar period: see answer, above. Rural-urban differences in T1D Incidence of T1D in Adults: Here again, there are too few data: only ten percent (7 of the 71 studies) explored the differences in the incidence of T1D in rural vs urban areas. A significantly higher urban proportion of the incidence of T1D among young adults and adults was found in 4 of these 7, (Iran (Fars) [37], Lithuania (Nationwide) [11], Italy (Pavia) [38], and United States of America (Wisconsin) [39]). In another one from Poland (Bialystok), a significantly rising incidence trend was found in the rural areas but not in the urban regions [40]. In the Province of Rzeszow no differences were found between the rural and urban incidences [41], nor in Turin, Italy [9]. We did not feel that this information deserved to be included in the MS. In the discussion (main manuscript lines 216:218), we indicate: In this SR a significantly higher urban proportion of T1D incidence among adults was found in 4 of the 7 studies reporting differences between rural vs urban areas [17, 37-39]. 4. Was there any difference by clinical presentation between children and adults? Again, very few data. We now indicate in the discussion, lines 228:231: Similarly, this SR did not dispose of sufficient data to document differences in the clinical presentation of T1D of adults and children as suggested elsewhere [2, 30]; indeed only two of the 71 studies describe differences in clinical presentation of T1D between adults and children [31, 32]. 5. What was the age-specific/age-standardized incidence of type 1 diabetes? What was the annual incidence rate in the older age groups vs. young adults? All incidences reported in our MS are expressed per 100.000 persons/per year. The annual incidence rates in the different age groups are in Additional File 4 Table 1.

6. Was there any difference in the type of auto antibodies detected between age groups? Only one paper [42] explores this question. It is now indicated in the discussion. Lines 163-168: Auto-antibodies against beta-cell antigens or the C-peptide were included in the T1D diagnostic criteria in 14 studies [2, 3, 14, 27, 37, 42-50], detection of ICAs was reported in 9 studies [2, 3, 27, 37, 43-45, 47, 48], IAA in 4 studies [2, 3, 27, 45], IA2 in 5 studies [2, 3, 14, 27, 49], and GAD in 11 studies [2, 3, 14, 27, 42-44, 47, 49-51]. In one paper difference of auto-antibodies by age group (0-19) was explored but no significant differences were detected [42]. Quality of written English: Needs some language corrections before being published References: A senior researcher, and native English speaker edited the final version of our MS. 1. Tran F, Stone M, Huang CY, Lloyd M, Woodhead HJ, Elliott KD, Crock PA, Howard NJ, Craig ME: Population-based incidence of diabetes in Australian youth aged 10-18 yr: increase in type 1 diabetes but not type 2 diabetes. Pediatric diabetes 2014, 15(8):585-590. 2. Vandewalle CL, Coeckelberghs MI, De Leeuw IH, Du Caju MV, Schuit FC, Pipeleers DG, Gorus FK: Epidemiology, clinical aspects, and biology of IDDM patients under age 40 years. Comparison of data from Antwerp with complete ascertainment with data from Belgium with 40% ascertainment. The Belgian Diabetes Registry. Diabetes care 1997, 20(10):1556-1561. 3. Weets I, De Leeuw IH, Du Caju MV, Rooman R, Keymeulen B, Mathieu C, Rottiers R, Daubresse JC, Rocour-Brumioul D, Pipeleers DG et al: The incidence of type 1 diabetes in the age group 0-39 years has not increased in Antwerp (Belgium) between 1989 and 2000: evidence for earlier disease manifestation. Diabetes care 2002, 25(5):840-846. 4. Charkaluk ML, Czernichow P, Levy-Marchal C: Incidence data of childhood-onset type I diabetes in France during 1988-1997: the case for a shift toward younger age at onset. Pediatr Res 2002, 52(6):859-862. 5. Blumenfeld O, Dichtiar R, Shohat T, Israel IRSG: Trends in the incidence of type 1 diabetes among Jews and Arabs in Israel. Pediatric diabetes 2014, 15(6):422-427. 6. Sella T, Shoshan A, Goren I, Shalev V, Blumenfeld O, Laron Z, Chodick G: A retrospective study of the incidence of diagnosed Type 1 diabetes among children and adolescents in a large health organization in Israel, 2000-2008. Diabetic medicine : a journal of the British Diabetic Association 2011, 28(1):48-53. 7. Garancini P, Gallus G, Calori G, Formigaro F, Micossi P: Incidence and prevalence rates of diabetes mellitus in Italy from routine data: a methodological assessment. European journal of epidemiology 1991, 7(1):55-63.

8. Muntoni S, Songini M: High incidence rate of IDDM in Sardinia. Sardinian Collaborative Group for Epidemiology of IDDM. Diabetes care 1992, 15(10):1317-1322. 9. Bruno G, Merletti F, Vuolo A, Pisu E, Giorio M, Pagano G: Sex differences in incidence of IDDM in age-group 15-29 yr. Higher risk in males in Province of Turin, Italy. Diabetes care 1993, 16(1):133-136. 10. Ostrauskas R, Zalinkevicius R: Incidence in young adulthood-onset Type 1 diabetes mellitus in Lithuania during 1991-1997. Lithuanian Epidemiology Diabetes Study Group. Diabetes, nutrition & metabolism 2000, 13(2):68-74. 11. Pundziute-Lycka A, Urbonaite B, Ostrauskas R, Zalinkevicius R, Dahlquist GG: Incidence of type 1 diabetes in Lithuanians aged 0-39 years varies by the urban-rural setting, and the time change differs for men and women during 1991-2000. Diabetes care 2003, 26(3):671-676. 12. Sobel-Maruniak A, Grzywa M, Orlowska-Florek R, Staniszewski A: The rising incidence of type 1 diabetes in south-eastern Poland. A study of the 0-29 yearold age group, 1980-1999. Endokrynol Pol 2006, 57(2):127-130. 13. Goday A, Castell C, Tresserras R, Canela J, Taberner JL, Lloveras G: Incidence of type 1 (insulin-dependent) diabetes mellitus in Catalonia, Spain. The Catalan Epidemiology Diabetes Study Group. Diabetologia 1992, 35(3):267-271. 14. Forga L, Goni MJ, Ibanez B, Cambra K, Mozas D, Chueca M: [Incidence of type 1 diabetes in Navarre, 2009-2012]. Anales del sistema sanitario de Navarra 2014, 37(2):241-247. 15. Blohme G, Nystrom L, Arnqvist HJ, Lithner F, Littorin B, Olsson PO, Schersten B, Wibell L, Ostman J: Male predominance of type 1 (insulin-dependent) diabetes mellitus in young adults: results from a 5-year prospective nationwide study of the 15-34-year age group in Sweden. Diabetologia 1992, 35(1):56-62. 16. Pundziute-Lycka A, Dahlquist G, Nystrom L, Arnqvist H, Bjork E, Blohme G, Bolinder J, Eriksson JW, Sundkvist G, Ostman J: The incidence of Type I diabetes has not increased but shifted to a younger age at diagnosis in the 0-34 years group in Sweden 1983-1998. Diabetologia 2002, 45(6):783-791. 17. Ostman J, Lonnberg G, Arnqvist HJ, Blohme G, Bolinder J, Ekbom Schnell A, Eriksson JW, Gudbjornsdottir S, Sundkvist G, Nystrom L: Gender differences and temporal variation in the incidence of type 1 diabetes: results of 8012 cases in the nationwide Diabetes Incidence Study in Sweden 1983-2002. Journal of internal medicine 2008, 263(4):386-394. 18. Nystrom L, Dahlquist G, Ostman J, Wall S, Arnqvist H, Blohme G, Lithner F, Littorin B, Schersten B, Wibell L: Risk of developing insulin-dependent diabetes mellitus (IDDM) before 35 years of age: indications of climatological determinants for age at onset. Int J Epidemiol 1992, 21(2):352-358. 19. Bingley PJ, Gale EA: Incidence of insulin dependent diabetes in England: a study in the Oxford region, 1985-6. BMJ 1989, 298(6673):558-560. 20. Wagenknecht LE, Roseman JM, Alexander WJ: Epidemiology of IDDM in black and white children in Jefferson County, Alabama, 1979-1985. Diabetes 1989, 38(5):629-633.

21. Kostraba JN, Gay EC, Cai Y, Cruickshanks KJ, Rewers MJ, Klingensmith GJ, Chase HP, Hamman RF: Incidence of insulin-dependent diabetes mellitus in Colorado. Epidemiology 1992, 3(3):232-238. 22. Gorham ED, Garland FC, Barrett-Connor E, Garland CF, Wingard DL, Pugh WM: Incidence of insulin-dependent diabetes mellitus in young adults: experience of 1,587,630 US Navy enlisted personnel. American journal of epidemiology 1993, 138(11):984-987. 23. Washington RE, Orchard TJ, Arena VC, Laporte RE, Tull ES: Incidence of type 1 and type 2 diabetes in youth in the U.S. Virgin Islands, 2001-2010. Pediatric diabetes 2013, 14(4):280-287. 24. The DIAMOND Project Group: Incidence and trends of childhood Type 1 diabetes worldwide 1990-1999. The DIAMOND project Group. Diabet Med 2006, 23(8):857-866. 25. Patterson CC, Dahlquist GG, Gyurus E, Green A, Soltesz G: Incidence trends for childhood type 1 diabetes in Europe during 1989-2003 and predicted new cases 2005-20: a multicentre prospective registration study. Lancet 2009, 373(9680):2027-2033. 26. Patterson CC, Gyurus E, Rosenbauer J, Cinek O, Neu A, Schober E, Parslow RC, Joner G, Svensson J, Castell C et al: Trends in childhood type 1 diabetes incidence in Europe during 1989-2008: evidence of non-uniformity over time in rates of increase. Diabetologia 2012, 55(8):2142-2147. 27. Weets I, Rooman R, Coeckelberghs M, De Block C, Van Gaal L, Kaufman JM, Keymeulen B, Mathieu C, Weber E, Pipeleers DG et al: The age at diagnosis of type 1 diabetes continues to decrease in Belgian boys but not in girls: a 15-year survey. Diabetes Metab Res Rev 2007, 23(8):637-643. 28. Ostrauskas R, Zalinkevicius R, Jurgeviciene N, Radzeviciene L, Lasaite L: The incidence of type 1 diabetes mellitus among 15-34 years aged Lithuanian population: 18-year incidence study based on prospective databases. BMC public health 2011, 11:813. 29. Dahlquist GG, Nystrom L, Patterson CC: Incidence of Type 1 Diabetes in Sweden Among Individuals Aged 0-34 Years, 1983-2007: An analysis of time trends. Diabetes Care 2011, 34(8):1754-1759. 30. Koton S: Incidence of type 1 diabetes mellitus in the 0- to 17-yr-old Israel population, 1997-2003. Pediatric diabetes 2007, 8(2):60-66. 31. Karjalainen J, Salmela P, Ilonen J, Surcel HM, Knip M: A comparison of childhood and adult type I diabetes mellitus. The New England journal of medicine 1989, 320(14):881-886. 32. Sabbah E, Savola K, Ebeling T, Kulmala P, Vahasalo P, Ilonen J, Salmela PI, Knip M: Genetic, autoimmune, and clinical characteristics of childhood- and adultonset type 1 diabetes. Diabetes care 2000, 23(9):1326-1332. 33. Tuomilehto J, Dabee J, Karvonen M, Dowse GK, Gareeboo H, Virtala E, Tiihonen M, Alberti KG, Zimmet PZ: Incidence of IDDM in Mauritian children and adolescents from 1986 to 1990. Diabetes care 1993, 16(12):1588-1591. 34. Libman IM, LaPorte RE, Becker D, Dorman JS, Drash AL, Kuller L: Was there an epidemic of diabetes in nonwhite adolescents in Allegheny County, Pennsylvania? Diabetes care 1998, 21(8):1278-1281.

35. Wagenknecht LE, Roseman JM, Herman WH: Increased incidence of insulindependent diabetes mellitus following an epidemic of Coxsackievirus B5. American journal of epidemiology 1991, 133(10):1024-1031. 36. Vehik K, Hamman RF, Lezotte D, Norris JM, Klingensmith G, Bloch C, Rewers M, Dabelea D: Increasing Incidence of Type 1 Diabetes in 0- to 17-Year-Old Colorado Youth. Diabetes care 2007, 30(3):503-509. 37. Pishdad GR: Low incidence of type 1 diabetes in Iran. Diabetes care 2005, 28(4):927-928. 38. Tenconi MT, Devoti G, Albani I, Lorini R, Martinetti M, Fratino P, Ferrari E, Ferrero E, Severi F: IDDM in the province of Pavia, Italy, from a population-based registry.a descriptive study. Diabetes care 1995, 18(7):1017-1019. 39. Allen C, Palta M, D'Alessio DJ: Incidence and differences in urban-rural seasonal variation of type 1 (insulin-dependent) diabetes in Wisconsin. Diabetologia 1986, 29(9):629-633. 40. Kretowski A, Kowalska I, Peczynska J, Urban M, Green A, Kinalska I: The large increase in incidence of Type I diabetes mellitus in Poland. Diabetologia 2001, 44 Suppl 3:B48-50. 41. Grzywa MA, Sobel AK: Incidence of IDDM in the province of Rzeszow, Poland, 0- to 29-year-old age-group, 1980-1992. Diabetes care 1995, 18(4):542-544. 42. Bell RA, Mayer-Davis EJ, Beyer JW, D'Agostino RB, Jr., Lawrence JM, Linder B, Liu LL, Marcovina SM, Rodriguez BL, Williams D et al: Diabetes in non-hispanic white youth: prevalence, incidence, and clinical characteristics: the SEARCH for Diabetes in Youth Study. Diabetes care 2009, 32 Suppl 2:S102-111. 43. Bruno G, Runzo C, Cavallo-Perin P, Merletti F, Rivetti M, Pinach S, Novelli G, Trovati M, Cerutti F, Pagano G: Incidence of type 1 and type 2 diabetes in adults aged 30-49 years: the population-based registry in the province of Turin, Italy. Diabetes care 2005, 28(11):2613-2619. 44. Bruno G, Novelli G, Panero F, Perotto M, Monasterolo F, Bona G, Perino A, Rabbone I, Cavallo-Perin P, Cerutti F: The incidence of type 1 diabetes is increasing in both children and young adults in Northern Italy: 1984 2004 temporal trends. Diabetologia 2009, 52(12):2531-2535. 45. Abellana R, Ascaso C, Carrasco JL, Castell C, Tresserras R: Geographical variability of the incidence of Type 1 diabetes in subjects younger than 30 years in Catalonia, Spain. Med Clin (Barc) 2009, 132(12):454-458. 46. Lammi N, Taskinen O, Moltchanova E, Notkola IL, Eriksson JG, Tuomilehto J, Karvonen M: A high incidence of type 1 diabetes and an alarming increase in the incidence of type 2 diabetes among young adults in Finland between 1992 and 1996. Diabetologia 2007, 50(7):1393-1400. 47. Thunander M, Petersson C, Jonzon K, Fornander J, Ossiansson B, Torn C, Edvardsson S, Landin-Olsson M: Incidence of type 1 and type 2 diabetes in adults and children in Kronoberg, Sweden. Diabetes research and clinical practice 2008, 82(2):247-255. 48. Molbak AG, Christau B, Marner B, Borch-Johnsen K, Nerup J: Incidence of insulindependent diabetes mellitus in age groups over 30 years in Denmark. Diabetic medicine : a journal of the British Diabetic Association 1994, 11(7):650-655.

49. Forga L, Goni MJ, Cambra K, Ibanez B, Mozas D, Chueca M, En Representacion del Grupo de Estudio de Diabetes tipo 1 de N: [Differences by age and gender in the incidence of type 1 diabetes in Navarre, Spain (2009-2011)]. Gaceta sanitaria / SESPAS 2013, 27(6):537-540. 50. Lin WH, Wang MC, Wang WM, Yang DC, Lam CF, Roan JN, Li CY: Incidence of and mortality from Type I diabetes in Taiwan from 1999 through 2010: a nationwide cohort study. PloS one 2014, 9(1):e86172. 51. Lammi N, Taskinen O, Moltchanova E, Notkola IL, Eriksson JG, Tuomilehto J, Karvonen M: A high incidence of type 1 diabetes and an alarming increase in the incidence of type 2 diabetes among young adults in Finland between 1992 and 1996. Diabetologia 2007, 50(7):1393-1400.