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Global estimates of incidence of type 1 diabetes in children and adolescents: Results from the International Diabetes Federation Atlas, 10th edition

Published:December 06, 2021DOI:https://doi.org/10.1016/j.diabres.2021.109083

      Abstract

      Background

      Type 1 diabetes (T1D) incidence in children and adolescents varies widely, and is increasing in many nations. The 10th edition of the International Diabetes Federation Atlas estimated incident cases in 2021 for 215 countries/territories (“countries”).

      Methods

      Studies on T1D incidence for young people aged 0–19 years were sourced and graded using previously described methods. For countries without studies, data were extrapolated from similar nearby countries.

      Results

      An estimated 108,300 children under 15 years will be diagnosed in 2021, a number rising to 149,500 when the age range extends to under 20 years. The ratio of incidence in 15–19 years compared to those aged 0–14 years was particularly high in some countries in sub-Saharan Africa, North Africa/Middle East, and in Mexico.
      Only 97 countries have their own incidence data, with extrapolation required for some very populous nations. Most data published were not recent, with 27 countries (28%) having data in which the last study year was 2015 or afterwards, and 26 (27%) having no data after 1999.

      Conclusions

      Many countries have recent data but there are large gaps globally. Such data are critical for allocation of resources, teaching, training, and advocacy. All countries are encouraged to collect and publish current data.

      Keywords

      1. Introduction

      Type 1 diabetes (T1D) is the commonest form of diabetes in children and adolescents, but type 2 diabetes, monogenic diabetes, and other forms also occur (

      Mayer-Davis E, Kahkoska A, Jefferies C, Dabelea D, Balde N, Gong C, et al. ISPAD clinical practice consensus guidelines 2018: Definition, epidemiology, and classification of diabetes in children and adolescents. Pediatr Diabetes. 2018;19:7-19 PMID: 30226024 10.1111/pedi.12773.

      ). T1D is a complex condition to manage. Insulin injections are needed for survival, and good outcomes can only be achieved with multiple daily injections, self-monitoring of blood glucose, comprehensive diabetes education and guidance from skilled health professionals (

      Ogle G, von Oettingen J, Middlehurst A, Hanas R, Orchard T. Levels of type 1 diabetes care in children and adolescents for countries at varying resource levels. Pediatr Diabetes. 2019;20(1):93-8 PMID: 30471084 10.1111/pedi.12801.

      ).
      The International Diabetes Federation (IDF) Atlas is regularly updated to provide evidence to raise awareness of diabetes and inform development of national diabetes plans that are appropriate to unique local contexts. Numbers of new (incident) and existing (prevalent) T1D cases are increasing each year due to rising incidence in many countries/territories (hereafter called “countries”) (

      Tuomilehto J, Ogle G, Lund-Blix N, Stene L. Update on worldwide trends in occurrence of childhood type 1 diabetes in 2020. Pediatric endocrinology reviews : PER. 2020;17:198-209 PMID: 32208564 10.17458/per.vol17.2020.tol.epidemiologychildtype1diabetes.

      ), and reductions in mortality (

      Sandy J, Besançon S, Sidibé A, Minkailou M, Togo A, Ogle G. Rapid increases in observed incidence and prevalence of type 1 diabetes in children and youth in Mali, 2007-2016. Pediatr Diabetes. 2021:1-7 10.1111/pedi.13191.

      ). This 10th edition of the IDF Atlas estimates that 1,211,900 children and adolescents younger than 20 years have T1D globally.
      T1D incidence varies around the world with some regions having much higher incidences than others. Incidence has been increasing in recent decades in nearly all countries studied, although there is now evidence that this increase maybe tailing off or has ceased in some high-income countries (

      Tuomilehto J, Ogle G, Lund-Blix N, Stene L. Update on worldwide trends in occurrence of childhood type 1 diabetes in 2020. Pediatric endocrinology reviews : PER. 2020;17:198-209 PMID: 32208564 10.17458/per.vol17.2020.tol.epidemiologychildtype1diabetes.

      ,

      Patterson C, Harjutsalo V, Rosenbauer J, Neu A, Cinek O, Skrivarhaug T, et al. Trends and cyclical variation in the incidence of childhood type 1 diabetes in 26 European centres in the 25 year period 1989-2013: A multicentre prospective registration study. Diabetologia. 2019;62(3):408-17 PMID: 30483858 10.1007/s00125-018-4763-3.

      ,

      Patterson C, Karuranga S, Salpea P, Saeedi P, Dahlquist G, Soltesz G, et al. Worldwide estimates of incidence, prevalence and mortality of type 1 diabetes in children and adolescents: Results from the International Diabetes Federation Diabetes Atlas, 9th edition. Diab Res Clin Pract. 2019;157:107842.

      ). The reasons for this increase are unclear, however various environmental factors have been proposed and are being investigated (

      Tuomilehto J, Ogle G, Lund-Blix N, Stene L. Update on worldwide trends in occurrence of childhood type 1 diabetes in 2020. Pediatric endocrinology reviews : PER. 2020;17:198-209 PMID: 32208564 10.17458/per.vol17.2020.tol.epidemiologychildtype1diabetes.

      ,
      • Katsarou A.
      • Gudbjörnsdottir S.
      • Rawshani A.
      • Dabelea D.
      • Bonifacio E.
      • Anderson B.J.
      • et al.
      Type 1 diabetes mellitus.
      ).
      Complimentary to the 10th edition of the IDF Atlas, this article aims to present current country incidence data, and to identify knowledge gaps.

      2. Subjects, materials and methods

      The incidence estimates of T1D in children and adolescents (0–14 and 0–19 years of age) were produced by the 10th edition IDF Atlas T1D in Children and Adolescents Special Interest Group, using methodology from the 9th edition of the IDF Atlas as previously described (

      Patterson C, Karuranga S, Salpea P, Saeedi P, Dahlquist G, Soltesz G, et al. Worldwide estimates of incidence, prevalence and mortality of type 1 diabetes in children and adolescents: Results from the International Diabetes Federation Diabetes Atlas, 9th edition. Diab Res Clin Pract. 2019;157:107842.

      ), and updated in 2021 with a further search using Covidence systematic review software (Veritas Health Innovation, Melbourne, Australia).
      The scientific literature was searched, without language restrictions, for data sources that contained population-based studies on T1D incidence in children and adolescents aged up to 20 years. If more than one study was available for a country, the following criteria were applied to select the most suitable: recent; population-based studies; high (≥90%) ascertainment level; covering a large part of the country; providing age- and sex-specific rates; and including the age ranges 0–14 and 15–19 years. For some countries where two or more studies met these criteria to an equal extent, results were combined by averaging age- and sex-specific rates.
      If a country did not have any information available, the incidence rate for ages under 15 years was estimated using data from a similar country, based on geographical proximity, income, and ethnicity. For ages 15–19 years, in the absence of specific country or area data the incidence rate was estimated using the average regional ratio of incidence in the 15–19 years and 0–14 years age groups.
      Unless stated, data are presented for ages 0–14 years.

      3. Results

      3.1 Atlas estimates

      3.1.1 Global results

      This study estimates that around 108,300 children and adolescents under 15 years will be diagnosed in 2021, and this number rises to 149,500 when the age range extends to under 20 years (Table 1).
      Table 1Estimated incident cases.
      IDF RegionNumber of countries with incidence rates available (%)Incident cases per annum (1000 s)
      014 years019 years
      AFR6/48 (12.5)7.719.7
      EUR44/59 (74.6)24.731.0
      MENA12/21 (57.1)18.125.0
      NAC8/23 (34.8)18.724.4
      SACA12/19 (63.2)9.512.3
      SEA4/7 (57.1)20.525.7
      WP11/38 (29)0.111.6
      World97/215 (45.1)108.3149.5
      IDF = International Diabetes Federation; AFR = Africa; EUR = Europe; MENA = Middle East and North Africa, NAC = North America and Caribbean; SACA = South and Central America; SEA = South-East Asia; and WP = Western Pacific.
      T1D age-standardised incidences are highest in populations of northern European origin, and in several countries in the Middle Eastern and North African Region (Table 2, Fig. 1, and Supplementary Material 1). Table 2 shows the ten countries with the highest published age-standardised incidence of T1D reported in children aged 0–14 years, and estimated number of incident cases of T1D in children aged 0–14 years. India and the United States of America had the highest numbers of estimated incident cases of T1D, followed by various other populous countries.
      Table 2The ten countries/territories with the highest a) published age-standardised incidence of type 1 diabetes reported in children aged 0–14 years; and b) estimated number of incident cases of type 1 diabetes in children aged 0–14 years.
      Highest age-standardised incidenceHighest incident cases (2021)
      RankCountry/territoryIDF RegionIncidence (per 100,000 per annum)RankCountry/territoryIDF RegionIncident cases
      1FinlandEUR52.21IndiaSEA19,194
      2SwedenEUR44.12United States of AmericaNAC15,288
      3KuwaitMENA41.73BrazilSACA7,117
      4QatarMENA38.14ChinaWP4,900
      5CanadaNAC37.95AlgeriaMENA4,874
      6AlgeriaMENA34.86Russian FederationEUR3,345
      7NorwayEUR33.67GermanyEUR2,845
      8Saudi ArabiaMENA31.48United KingdomEUR2,713
      9United KingdomEUR28.19Saudi ArabiaMENA2,680
      10IrelandEUR27.510CanadaNAC2,274
      IDF = International Diabetes Federation; EUR = Europe; MENA = Middle East and North Africa, NAC = North America and Caribbean; SACA = South and Central America; SEA = South-East Asia; and WP = Western Pacific.
      Figure thumbnail gr1a
      Fig. 1Published age-standardised incidence of type 1 diabetes reported in children aged 0–14 years.
      Figure thumbnail gr1b
      Fig. 1Published age-standardised incidence of type 1 diabetes reported in children aged 0–14 years.
      Similar patterns of age-standardised T1D incidence and estimated incident cases of T1D per year were seen when considering ages 0–19 years (Supplementary Material 1).

      3.1.2 Age ratio calculations for 15–19-year age group

      All included studies had data for 0–14 years. However, only 26 countries also had data for 15–19 years (Supplementary Material 2).
      The mean ratio of incidence 15–19 years compared to incidence 0–14 years was calculated by IDF Region (Fig. 2). The Africa Region ratio (5.91) was over three times higher than any other region.
      Figure thumbnail gr2
      Fig. 2Ratio estimates for type 1 diabetes 0–14-year rates to 15–19-year rates. IAFR = Africa; EUR = Europe; MENA = Middle East and North Africa, NAC = North America and Caribbean; SACA = South and Central America; SEA = South-East Asia; and WP = Western Pacific.

      3.1.3 Income level

      The World Bank categorises all countries into four income groups (

      World Bank. World Bank country and lending groups. Available at: https://datahelpdesk.worldbank.org/knowledgebase/articles/906519-world-bank-country-and-lending-groups, accessed 28th June 2021.

      ). Within high-income countries, highest incidences were seen in Northern European and some Middle Eastern countries, with much lower rates in Japan and Singapore (Supplementary Material 1). For upper-middle income countries, rates were again highest in European countries as well as Brazil, and lower in China and some other non-European population countries. For lower-middle income countries, the highest rates were seen in Northern African countries and the Ukraine. For low-Income countries, incidence was highest in Eritrea.

      3.2 Gaps in knowledge

      3.2.1 Data extrapolation

      Only 97 of the 215 countries covered by the Atlas have their own incidence data (Table 1, Fig. 1, and Supplementary Material 1). Table 3 lists countries used for extrapolation and the countries without incidence data to which rates were extrapolated.
      Table 3Data extrapolation.
      Source country/territoryCountry/territory data extrapolated to
      African Region
      EritreaDjibouti and Somalia
      GabonBenin, Cameroon, Cape Verde, Congo, Côte d'Ivoire, Equatorial Guinea, Ghana, Mauritania, Nigeria, Sao Tome and Principe and Senegal
      MaliBurkina Faso, Central African Republic, Chad, Gambia, Guinea, Guinea-Bissau, Liberia, Niger, Sierra Leone and Togo
      MauritiusComoros, Mayotte and Seychelles
      United Republic of TanzaniaAngola, Eswatini, Kenya, Lesotho, Madagascar, Malawi, Mozambique, Namibia, South Africa, Uganda, Zambia and Zimbabwe
      RwandaBotswana, Burundi, Democratic Republic of the Congo
      SudanSouth Sudan
      European Region
      ChinaKazakhstan and Kyrgyzstan
      DenmarkFaroe Islands and Greenland
      FranceMonaco
      ItalyHoly See and San Marino
      North MacedoniaAlbania
      RomaniaMoldova
      SpainAndorra
      SwitzerlandLiechtenstein
      TurkeyTurkmenistan
      United KingdomChannel Islands and Isle of Man
      UzbekistanTajikistan
      Middle Eastern and Northern African Region
      AlgeriaMorocco
      JordanIraq, Lebanon, State of Palestine and Syria
      OmanBahrain, United Arab Emirates and Yemen
      UzbekistanAfghanistan
      North American and Caribbean Region
      BarbadosGrenada, St Kitts and Nevis, St Lucia, St Vincent and the Grenadines, and Trinidad, and Tobago
      CubaCayman Islands and Jamaica
      Dominican RepublicHaiti
      GabonBermuda
      MexicoBelize
      US Virgin IslandsBritish Virgin Islands
      VenezuelaAruba, Curaçao, Guyana and Suriname
      South and Central American Region
      ColombiaCosta Rica, Ecuador and Panama
      MexicoEl Salvador, Guatemala, Honduras and Nicaragua
      South-East Asian Region
      IndiaBhutan, Nepal and Sri Lanka
      Western Pacific Region
      ChinaMongolia
      FijiAmerican Samoa, French Polynesia, Kiribati, New Caledonia, Northern Mariana Islands, Samoa, Tonga, Tuvalu and Vanuatu
      Hong Kong, ChinaMacao
      ThailandBrunei Darussalam, Cambodia, Indonesia, Laos, Malaysia, Myanmar, Philippines, Timor L'Este and Vietnam
      Papua New GuineaGuam, Marshall Islands, Micronesia (Federated States of), Nauru, Palau, and the Solomon Islands
      Republic of KoreaDemocratic People's Republic of Korea

      3.2.2 Period of data

      Much published data were not recent, with only 27 of the 97 countries (28%) including data from years as recent as 2015. Thirty-seven countries (38%) had data with the most recent year between 2010 and 2014, 7 (7%) with most recent years between 2000 and 2009, and 26 (27%) with most recent year between 1990 and 1999. The median most recent year of data was 2012. Fig. 3 shows the geographical variation around period of most recent data, indicating the limited data from the African Region.

      4. Discussion

      This article presents most recent country T1D incidence data for children and adolescents and identifies various gaps.
      In the two years since the IDF Atlas 9th Edition in 2019 (

      International Diabetes Federation. IDF diabetes atlas. 9th edition. International Diabetes Federation: Brussels. 2019.

      ), estimated numbers of new T1D cases 0–14 years have increased from 98,200 to 108,300 and for 0–19 years from 128,900 to 149,500. Increases were most pronounced in the African, Middle East and North Africa Regions. For the African Region, this is due to new data from Gabon (
      • Pambou Damiens A.
      • Ganga –Zandzou P.S.
      • Tsoucka Ibounde E.
      • Kayemba-Kay's S.
      • Baye E.
      • Biloghe P.
      • et al.
      Type 1 diabetes mellitus in Gabon: A study of epidemiological aspects.
      ) and Eritrea (

      Mebrahtu G, Maniam J, James S, Ogle G. High incidence of type 1 diabetes in adolescents and young adults in Eritrea. Diabet Med. 2021;38:e14544 10.1111/dme.

      ), as well as updated data from Tanzania (

      Jasem D, Majaliwa E, Ramiaya K, Najem S, Swai A, Ludvigsson J. Incidence, prevalence and clinical manifestations at onset of juvenile diabetes in Tanzania. Diabetes Res Clin Pract. 2019;156:107817 10.1016/j.diabres.2019.

      ) that were higher than previous estimates and also extrapolated to various other countries in sub-Saharan Africa without any data. For the Middle East and North Africa Region, new data from Algeria increased estimates.
      These data continue to show great differences globally, with incidence in the highest country (Finland) over fifty times higher than various countries in South Asia, Africa, South and Central America and the Western Pacific. It must be noted that some countries had studies that are quite dated, and also there is also the strong possibility of underestimation of incidence rates because of death through missed diagnosis in some countries (

      Ogle G, von Oettingen J, Middlehurst A, Hanas R, Orchard T. Levels of type 1 diabetes care in children and adolescents for countries at varying resource levels. Pediatr Diabetes. 2019;20(1):93-8 PMID: 30471084 10.1111/pedi.12801.

      ,

      Sandy J, Besançon S, Sidibé A, Minkailou M, Togo A, Ogle G. Rapid increases in observed incidence and prevalence of type 1 diabetes in children and youth in Mali, 2007-2016. Pediatr Diabetes. 2021:1-7 10.1111/pedi.13191.

      ,
      • Pambou Damiens A.
      • Ganga –Zandzou P.S.
      • Tsoucka Ibounde E.
      • Kayemba-Kay's S.
      • Baye E.
      • Biloghe P.
      • et al.
      Type 1 diabetes mellitus in Gabon: A study of epidemiological aspects.
      ,

      Marshall S, Edidin DA, VC, Becker D, Bunker C, Gishoma C, Gishoma F, et al. Prevalence and incidence of clinically recognized cases of Type 1 diabetes in children and adolescents in Rwanda, Africa. Diabet Med. 2015;32(9):1186-92.

      ). However, both Finland and Japan have recent data and well-resourced health systems but still have a 24-fold difference in rates 0–14 years (52.2 versus 2.2 per 100,000 per year).
      Only 97 of the 215 countries covered by the Atlas have their own incidence data. Countries without any data include some very populous nations such as Nigeria, Indonesia, Philippines, Vietnam, and South Africa. In these cases, data are extrapolated from a nearby country with similar characteristics, but there are various reasons why such data may not be very accurate. Gaps are greatest in sub-Saharan Africa and parts of Asia, South and Central America, and the Caribbean. Only six of the 48 countries in the Africa Region have data. This sparsity of data results in wide extrapolations of incidence data across the continent. Given that this region has great genetic diversity, these extrapolations may be inaccurate (

      Tishkoff S, Reed F, Friedlaender F, Ehret C, Ranciaro A, Froment A, et al. The genetic structure and history of Africans and African Americans. Science. 2009;324(5930):1035–44 10.126/science.1172257.

      ).
      Most data published were also not recent; only 27 countries (28%) having data in which the last study year was as recent as 2015, with 26 (27%) having most recent data between 1990 and 1999. Given the global rise in incidence over the last few decades, incidence figures are likely to be markedly under-estimated. For instance, a 3% annual rise over 20 years will increase incidence by 81%.
      Incidence data are also much more limited for the 15–19 year than for the 10–14-year age groups, with only 26 countries having 15–19-year data. This is particularly important as the peak age of onset of T1D varies substantially. In Finland, T1D incidence peaks in the 5–9 years age group (
      • Harjutsalo H.
      • Sund R.
      • Knip M.
      • Per-Henrik Groop P.-H.
      Incidence of type 1 diabetes in Finland.
      ) and in most other non-European origin populations in the 10–14 years group (

      Tuomilehto J, Ogle G, Lund-Blix N, Stene L. Update on worldwide trends in occurrence of childhood type 1 diabetes in 2020. Pediatric endocrinology reviews : PER. 2020;17:198-209 PMID: 32208564 10.17458/per.vol17.2020.tol.epidemiologychildtype1diabetes.

      ,
      • Diaz-Valencia P.
      • Bougnères P.
      • Valleron A.-J.
      Global epidemiology of type 1 diabetes in young adults and adults: a systematic review.
      ). T1D onset has become earlier over the last few decades in these populations (

      International Diabetes Federation. IDF diabetes atlas. 9th edition. International Diabetes Federation: Brussels. 2019.

      ). However, peak age of T1D onset in most sub-Saharan African studies is later, in the late teens or even later (

      Sandy J, Besançon S, Sidibé A, Minkailou M, Togo A, Ogle G. Rapid increases in observed incidence and prevalence of type 1 diabetes in children and youth in Mali, 2007-2016. Pediatr Diabetes. 2021:1-7 10.1111/pedi.13191.

      ,

      Mebrahtu G, Maniam J, James S, Ogle G. High incidence of type 1 diabetes in adolescents and young adults in Eritrea. Diabet Med. 2021;38:e14544 10.1111/dme.

      ,

      Marshall S, Edidin DA, VC, Becker D, Bunker C, Gishoma C, Gishoma F, et al. Prevalence and incidence of clinically recognized cases of Type 1 diabetes in children and adolescents in Rwanda, Africa. Diabet Med. 2015;32(9):1186-92.

      ,

      Alemu S, Dessie A, Seid E, Bard E, Lee P, Trimble E, et al. Insulin-requiring diabetes in rural Ethiopia: should we reopen the case for malnutrition-related diabetes? Diabetologia. 2009;52(9):1842-5.

      ). Possible reasons for this include different phenotypes of T1D, a greater likelihood of deaths with missed diagnosis in younger children, and a temporal delay in the environmental changes that have resulted in earlier age of onset in European-origin populations. A higher ratio of onset at 15–19 years is also seen in Iran (Islamic Republic of), Sudan, Libya, and Mexico, raising the ratio for their respective Regions.
      Given the very wide range of measured T1D incidence and the fact that incidence has been increasing over time in most countries (

      Tuomilehto J, Ogle G, Lund-Blix N, Stene L. Update on worldwide trends in occurrence of childhood type 1 diabetes in 2020. Pediatric endocrinology reviews : PER. 2020;17:198-209 PMID: 32208564 10.17458/per.vol17.2020.tol.epidemiologychildtype1diabetes.

      ,

      Patterson C, Harjutsalo V, Rosenbauer J, Neu A, Cinek O, Skrivarhaug T, et al. Trends and cyclical variation in the incidence of childhood type 1 diabetes in 26 European centres in the 25 year period 1989-2013: A multicentre prospective registration study. Diabetologia. 2019;62(3):408-17 PMID: 30483858 10.1007/s00125-018-4763-3.

      ), it is essential that countries ascertain their current rates of new and existing cases of T1D for children and adolescents. Knowledge of the number of new and existing cases is critical so that sufficient health resources can be allocated. These numbers inform health professional training and advocacy efforts.
      The authors and the IDF, Life for a Child, and the International Society for Pediatric and Adolescent Diabetes (ISPAD) are very willing to advise and foster new incidence studies in countries that either have no data or no recent data. The IDF Guide for Diabetes Epidemiological Studies, released in 2021 and available on the IDF website (

      International Diabetes Federation. International Diabetes Federation’s guide for diabetes epidemiologcial studies. Available at: https://www.idf.org/our-activities/epidemiology-research/idf-guide-for-diabetes-epidemiology-studies.html, accessed 24th September 2021. 2021.

      ), provides useful and practical information on how to plan, conduct, and report such studies.
      In summary, compared with the 9th edition of the IDF Atlas in 2019, estimated numbers of new cases of T1D have increased, particularly in the Africa, Middle East and North Africa Regions. However, less than half of the countries and territories covered by the Atlas have their own incidence data, with many studies having dated data. Data limitations can only be resolved with more, and more recent data. Efforts should be made by all countries to ascertain their current rates of new and existing cases of T1D for children and adolescents. Such information will guide allocation of health resources as well as health professional training and advocacy efforts.

      5. Authors’ contributions

      All authors (excluding SJ) co-designed the study, collected, and analysed the data. SJ wrote the first draft of the manuscript, and all authors contributed to the manuscript.

      Funding

      GDO, JM and ELK were partly funded by a grant from The Leona M and Harry B Helmsley Charitable Trust.

      Declaration of Competing Interest

      The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

      Acknowledgements

      We thank Suvi Karuranga (International Diabetes Federation, Brussels, Belgium) for her ongoing support, and Mapchart.net, whose software were used to create Fig. 3; work licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

      Appendix A. Supplementary data

      The following are the Supplementary data to this article:

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      2. Ogle G, von Oettingen J, Middlehurst A, Hanas R, Orchard T. Levels of type 1 diabetes care in children and adolescents for countries at varying resource levels. Pediatr Diabetes. 2019;20(1):93-8 PMID: 30471084 10.1111/pedi.12801.

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