News and insights brought to you by the International Diabetes Federation

IDF Diabetes Atlas IGT image

Let’s talk numbers: the IDF Diabetes Atlas 8th Edition 2017 reports that over 350 million people between 20 to 79 years worldwide are estimated to have developed impaired glucose tolerance (IGT). Translated, this estimate equates to more than every 14th person worldwide with impaired glucose regulation after testing for an oral glucose tolerance test (OGTT), routinely used for diagnosing type 2 diabetes.

IGT occurs when results are above the normal range (7.8 mmol/L (140.4 mg/dL) to 11.1 mmol/L (199.8 mg/dL)), but not high enough to be classified as having diabetes. IGT, also called prediabetes, carries a high risk for developing type 2 diabetes. Prediabetes is a term that covers varying degrees of altered glucose metabolism.

IGT is a time-bomb and it requires action. By 2045, it is projected that 587 million people will be diagnosed with IGT or 1 in 12 people aged 20 to 79 years. In general, women and men are equally affected, but differences do exist by lifespan. The prevalence of IGT in people under 50 is higher in men. Almost half of all adults with IGT are under the age of 50, and nearly one-third of them are between 20 to 39 years. If the condition is left untreated, people are not only at high risk of developing type 2 diabetes, but because of development of IGT at a young age, people in this category are very likely to spend many years at a higher risk for type 2 diabetes.

The majority of people with IGT live in low- and middle-income countries (72.3%). The IDF North America and Caribbean region has the highest prevalence of IGT (14.1%) among all IDF regions, with 1 in 7 adults affected. South-East Asia has the lowest prevalence (3.5%). The three countries with the highest number of people with IGT are China (48.6 million), USA (36.8 million) and Indonesia (27.7 million), accounting for almost one-third of the total number of people with IGT. Despite these alarming figures, National Diabetes Prevention plans still do not exist in many countries.

The numbers reflect a large distinct global population at risk for type 2 diabetes. Currently, IGT does not get much attention from healthcare providers, because many people experience no symptoms at first.1 People who have developed prediabetes are likely to stay undiagnosed and under the radar until the condition develops into type 2 diabetes. In addition to type 2 diabetes, IGT also increases the risk of cardiovascular disease (CVD) and other major health complications affecting the eyes, kidneys or nervous system.2 Previous research has estimated that up to 70% of people with IGT develop type 2 diabetes.2

Ignoring IGT may have a primary role in early mortality. Worldwide, over 4 million people (20-79 years) deaths were attributed to diabetes in 2017. This number is higher than the combined number of deaths from infectious diseases such as HIV/AIDS, Tuberculosis and Malaria. In the IDF South-East Asia region, over half a million diabetes-related deaths occur in people under the age of 60, while in Africa, three quarters of all deaths due to diabetes arise in this age group.

Prediabetes also has a significant economic role in terms of lost productivity and increased health systems cost. People with IGT are more susceptible to overuse healthcare services and are thus subject to higher healthcare expenditure. In the USA, for example, it was estimated that IGT accounted for USD 44 billion spent on healthcare.3

While IGT and other forms of impaired glucose tolerance put individuals at high risk for developing type 2 diabetes, in many cases these conditions are preventable and reversible. Meda Pavkov, a physician scientist from the Centers for Disease Control (CDC), weighs in on what is commonly known, but seldom acted upon. “Impaired Glucose Tolerance is a serious but preventable and reversible health condition. Both, persons who are affected and their physicians need to recognise this condition and take action. Losing weight, a healthy lifestyle and getting regular physical activity can prevent its progression to type 2 diabetes as well as reverse it back to a normal state.

The risk factors of prediabetes are the same as for type 2 diabetes: overweight, poor diet or poor nutrition, lack of physical activity, smoking, advanced age, and family history.4,5 There are a number of high quality studies which support the effectiveness of lifestyle interventions and changes in behaviour in preventing the progression of prediabetes to type 2 diabetes.6-8 Lifestyle modifications include diet, increased physical activity, or weight loss. Studies suggest that even a moderate reduction in weight and only half an hour of walking each day reduces the incidence of type 2 diabetes by more than 50%.

So, what should we do? The problem of IGT must be acknowledged, because we have measures to turn the trend around! As simple as it sounds, a healthy (ier) diet and more physical activity (e.g. walk/bike to work) can do the trick.

Impaired Glucose Tolerance is a serious but preventable and reversible health condition. Both, persons who are affected and their physicians need to recognise this condition and take action.


IDF Diabetes Atlas Key Messages What do they really mean?
Global prevalence of IGT in 2017 is 7.3% IGT is known to be interlinked with other chronic conditions, obesity and diabetes complications causing serious public health threat to our generation. Especially some parts of the world carry higher burden on this condition, such as the North America and Caribbean region, which has the highest prevalence of IGT (14.1%). Furthermore, China has 60 million people with IGT, which is 17% of the global total.
The number of people with IGT in 2017 is 352.1 million People with IGT are often unaware of their condition and therefore do not know it is important to take care of their health. One to three out of every four people with IGT will develop diabetes within a decade. It is important to note that nearly one-third (28.8%) of all those who currently have IGT are in the 20-39 age group and are therefore likely to spend many years at high risk and often not knowing.
34 million more people with IGT since 7th edition. By 2045, the number of people 20-79 years with IGT is projected to increase to 587 million IDF draws its estimates on reliable data sources and can observe a rising trend, but IGT is also preventable and reversible and these huge prevalence figures can be avoided. Prevention through healthy lifestyle such as physical activity and healthy diet will help prevent IGT. Government investments are needed to provide health education and healthy environments to live.



  1. Andersson S, Ekman I, Lindblad U, et al. Perceived symptoms in people living with impaired glucose tolerance. Nursing Research and Practice. 2011; 2011: 1-9.
  2. Nathan DM, Davidson MB, DeFronzo RA, et al. Impaired fasting glucose and impaired glucose tolerance. Diabetes Care 2007; 30: 753-9.
  3. Dall TM, Yang W, Halder P, et al. The economic burden of elevated blood glucose levels in 2012: diagnosed and undiagnosed diabetes, gestational diabetes mellitus, and prediabetes. Diabetes Care 2014; 37: 3172-9.
  4. Vazquez G, Duval S, Jacobs Jr DR, Silventoinen K. Comparison of body mass index, waist circumference, and waist/hip ratio in predicting incident diabetes: a meta-analysis. Epidemiol Rev 2007; 29: 115-28.
  5. Forouzanfar MH, Alexander L, Anderson HR, et al. Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. The Lancet 2015; 386: 2287-323.
  6. Diabetes Prevention Program Research Group. Long-term effects of lifestyle intervention or metformin on diabetes development and microvascular complications over 15-year follow-up: the Diabetes Prevention Program Outcomes Study. The Lancet Diabetes & Endocrinology 2015; 3: 866-75.
  7. Gilinsky AS, Kirk AF, Hughes AR, et al. Lifestyle interventions for type 2 diabetes prevention in women with prior gestational diabetes: a systematic review and meta-analysis of behavioural, anthropometric and metabolic outcomes. Prev Med Rep 2015; 2: 448-61.
  8. Howells L, Musaddaq B, McKay AJ, Majeed A. Clinical impact of lifestyle interventions for the prevention of diabetes: an overview of systematic reviews. BMJ Open 2016; 6:e013806.

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