Background: Impaired glucose tolerance (IGT) is an important risk marker for the development of type 2 diabetes. The 9th edition of the International Diabetes Federation (IDF) Diabetes Atlas provides updated estimates on the worldwide prevalence of IGT in 2019 and its projections for the years 2030 and 2045.

Methods: A literature review of studies reporting the age-specific prevalence of IGT between 1990 and 2019 was conducted. The number of studies that satisfied the selection criteria according to the analytical hierarchy process was limited to 62 studies (from 49 countries). A generalised linear regression model was used to estimate the prevalence of IGT in the world’s 211 countries and territories. IGT prevalence estimates for countries without high quality in-country data sources were extrapolated from countries deemed to be similar.

Results: In 2019, the estimated global prevalence of IGT in adults aged 20-79 years is 7.5% (374 million people). The vast majority (72.2%) of people with IGT live in low- and middle-income countries and 48.1% (180 million) are under the age of 50 years. The projected prevalences for 2030 and 2045 are estimated to be 8.0% and 8.6%, respectively. The IDF North America and Caribbean Region has the highest age-adjusted comparative prevalence of IGT (12.3%) in 2019, while the Europe Region has the lowest in 2019 (4.4%). The top three countries with the largest number of people in the age group 20-79 years with IGT in 2019 are China (54.5 million), the United States of America (37.4 million) and Indonesia (29.1 million), while Papua New Guinea (29.2%), Indonesia (17.8%) and New Zealand (17.5%) have the highest age-adjusted comparative prevalences of IGT in 2019.

Conclusion: The majority of people with IGT are living in low- and middle-income countries. Given that IGT signifies a risk for future diabetes, its early detection and intervention can play a crucial role in primary prevention of type 2 diabetes.


P. Saeedi: None. A. Kaundal: None. S. Karuranga: None. B. Malanda: None. A.A. Motala: None. P. Aschner: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim International GmbH, Merck Sharp & Dohme Corp., Sanofi. Speaker’s Bureau; Self; Novo Nordisk A/S. W. Rathmann: Advisory Panel; Self; AstraZeneca. Consultant; Self; Boehringer Ingelheim Pharmaceuticals, Inc. Research Support; Self; Novo Nordisk Inc. Speaker’s Bureau; Self; Eli Lilly and Company, Novo Nordisk Inc.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at