Intermediate states of hyperglycaemia, also known as prediabetes, is a condition that rarely makes headlines. Yet, it is a warning sign for diabetes. So, what exactly is intermediate hyperglycaemia, and why does it matter? In the early 2000s, the American Diabetes Association introduced the term “prediabetes”. It refers to people whose blood glucose levels are higher than normal but not yet in the range for diabetes, and who typically show no symptoms.
Experts argue that the criteria set by the ADA are too broad, labelling many people as having prediabetes when they may never go on to develop diabetes. Not only is the term unhelpful and unnecessary, but it can also affect a person’s mental health, causing undue stress and anxiety. The World Health Organization (WHO) does not recognise prediabetes as a formal diagnosis, but an intermediary condition. Their preferred term is intermediate hyperglycaemia, which encompasses impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). Although they may sound technical, simply put, intermediate hyperglycaemia is higher than normal blood glucose levels, but not high enough to qualify as type 2 diabetes.
Recognising intermediate hyperglycaemia matters because, without intervention, it can progress to type 2 diabetes. Along the way, it increases the likelihood of diabetes-related complications and premature death. The good news is that the condition is also an opportunity. With awareness, lifestyle adjustments, and, where necessary, medical support, people can stop or even reverse its course.
In 2024, more than 1.1 billion adults worldwide were living with impaired glucose tolerance (IGT) or impaired fasting glucose (IFG)
IFG is diagnosed when blood glucose levels are higher than normal after an overnight fast, but not high enough to meet the threshold for diabetes. It highlights difficulties in maintaining glucose control when the body is at rest, particularly in the liver’s ability to regulate glucose output overnight.
IGT, on the other hand, is diagnosed using the oral glucose tolerance test (OGTT), which measures the body’s response to a glucose surge after drinking a glucose solution. People with IGT exhibit higher-than-normal blood glucose levels two hours after this test, indicating that their muscles and other tissues are struggling to absorb and use glucose efficiently.
Some people may have only IFG, some only IGT, and others both. Identifying the type helps healthcare professionals better understand a person’s diabetes risk and the best lifestyle or medical interventions for each situation.
According to the International Diabetes Federation (IDF) Diabetes Atlas 11th edition, the prevalence of intermediate hyperglycaemia varies worldwide, ranging from as low as 5.5% in Ireland to over 40% in Nigeria. These variations reflect differences in health systems, screening practices and underlying risk factors. What remains consistent is the sheer number of people affected.
In 2024, more than 1.1 billion adults worldwide were living with IGT or IFG. Both conditions cut across income levels, though patterns differ. IGT is slightly more common in middle-income countries, while IFG rates are highest in high-income regions.
IGT affected around 635 million adults, with the highest prevalence in South-East Asia and the lowest in Europe. IFG was identified in about 488 million adults, most common in North America and the Caribbean.
Looking ahead, the numbers are set to rise sharply. By 2050, projections suggest 846 million people will have IGT and 648 million will have IFG. Together, this means that well over a billion adults – one in eight globally – will be living with these early warning signs of diabetes.
A family history of diabetes increases the likelihood of developing IFG or IGT, but genes alone do not determine a person’s future health
Intermediate hyperglycaemia arises from a mix of genetic, biological and lifestyle factors. A family history of diabetes increases the likelihood of developing IFG or IGT, but genes alone do not determine a person’s future health. Lifestyle choices play a decisive role in determining who goes on to develop diabetes. Nutrition high in processed foods, refined carbohydrates and sugary drinks, combined with a sedentary lifestyle, contribute to increased glucose levels.
Other health conditions, such as hypertension and high LDL cholesterol, frequently occur alongside IFG or IGT, further increasing the risk of diabetes. Demographics matter as well. Older adults are more likely to develop intermediate hyperglycaemia, and men show slightly higher prevalence than women. Although people of all body sizes can develop the condition, excess body weight further fuels insulin resistance.
The most redoubtable characteristic of the condition is its silence. Most people experience no apparent symptoms. When signs such as increased thirst, frequent urination, fatigue or blurred vision do occur, it usually indicates that type 2 diabetes has already developed. Because of this, blood tests are the only reliable way to detect IFG or IGT.
Diagnostic thresholds are well defined. According to the American Diabetes Association, intermediate hyperglycaemia is identified by fasting plasma glucose levels between 5.6 and 6.9 mmol/L (100 to 125 mg/dL), a two-hour plasma glucose result of 7.8 to 11.0 mmol/L (140 to 199 mg/dL) following an oral glucose tolerance test, or an HbA1c result between 5.7 and 6.4%.
In 2024, the International Diabetes Federation issued a Position Statement recommending the use of the 1-hour post-load plasma glucose (1-h PG) test as a more sensitive and practical tool for detecting intermediate hyperglycaemia and type 2 diabetes in people at risk. The statement proposes validated cut-off points of 155 mg/dL (8.6 mmol/L) for intermediate hyperglycaemia and 209 mg/dL (11.6 mmol/L) for type 2 diabetes, marking an important step towards earlier and more accurate diagnosis.
Each test offers a unique perspective on how the body manages glucose. Fasting plasma glucose reflects overnight control, the oral glucose tolerance test measures how glucose is managed after a meal, and HbA1c provides an average over the past two to three months. Used together, they offer a comprehensive picture of glucose regulation and help identify those most at risk.
Each test offers a unique perspective on how the body manages glucose. Used together, they offer a comprehensive picture of glucose regulation
Even though intermediate hyperglycaemia is not yet diabetes, it carries risks. Without changes, many people with IFG or IGT will develop type 2 diabetes within five to ten years. The concern does not end there. The condition is independently associated with higher risks of cardiovascular disease, including heart attack and stroke. Complications involving the kidneys, nerves and eyes can also begin before diabetes is diagnosed. In fact, it is often when a diabetes-related complication appears that diabetes is diagnosed.
The need for early identification and management is therefore urgent, both for individuals and for health systems that are already struggling under the weight of chronic conditions.
Intermediate hyperglycaemia can be turned around. Decades of research, including the landmark Diabetes Prevention Program, have demonstrated that lifestyle interventions can reduce the risk of progression to type 2 diabetes by nearly 60%. Even medication, such as metformin, has been shown to minimise the risk by about one-third. However, lifestyle changes remain the cornerstone of prevention.
The most effective strategies are simple but sustained. A healthy and balanced diet that includes whole grains, fruits, vegetables, lean proteins and healthy fats supports healthier glucose control. Regular physical activity — at least 150 minutes of moderate exercise each week — improves insulin sensitivity and helps maintain a healthy weight. For those who are overweight, even a modest weight reduction of 5–7% can have profound benefits.
At the same time, public health efforts that bring screening into daily primary care and community settings support diabetes prevention — especially in low- and middle-income countries, where access to formal healthcare is limited. Raising awareness, reducing stigma, and ensuring safe environments for exercise, as well as access to affordable and healthy food, are equally important in supporting long-term change.
The most effective strategies are simple but sustained. A diet rich in whole grains, fruits, vegetables, lean proteins and healthy fats supports healthier glucose control
Behind every number is a person navigating uncertainty. For someone told they have IFG or IGT, the diagnosis can feel unsettling. It is neither diabetes nor a clear health issue. Nonetheless, with the proper support, it can be empowering. Many people find that small, manageable changes, such as walking daily, preparing meals at home, or reducing sugary drinks, not only improve glucose levels but also bring better energy, sleep, and overall well-being.
Healthcare professionals, advocates, and policymakers all have a role to play in supporting people living with intermediate hyperglycaemia. That begins with language. Blame has no place here. The condition is not a personal failure; it is a signal that the body is under strain and needs support. A person-first, compassionate approach helps individuals feel capable of making changes, rather than overwhelmed by risk.
Intermediate hyperglycaemia is widespread across the world, even though experts do not always agree on its exact definition. What is clear, however, is that these early changes in blood glucose are common and signal an increased risk of developing type 2 diabetes, underscoring the scale of the challenge facing health systems worldwide.
