Elevated blood sugar levels within an hour of an oral glucose tolerance test (OGTT) can be a critical indicator, even before prediabetes sets in. This finding offers a glimmer of hope for those at risk, as it suggests a window of opportunity for early intervention and prevention of type 2 diabetes.
Researchers from the University of Tübingen, Helmholtz Munich, and the German Center for Diabetes Research (DZD) have discovered that individuals with elevated one-hour blood glucose levels respond exceptionally well to lifestyle changes. This discovery could lead to a new clinically relevant biomarker, allowing for more targeted and timely prevention strategies.
But here's where it gets controversial...
Prediabetes, often seen as a precursor to type 2 diabetes, doesn't always progress to full-blown diabetes. In fact, over 40% of those diagnosed with prediabetes don't develop diabetes within a decade. And here's the part most people miss: current ADA prediabetes criteria fail to identify around 20% of individuals who later develop diabetes, leaving them without an early warning. So, how can we better identify and treat those at risk?
To answer this question, researchers have been searching for more precise markers. Their attention turned to the one-hour plasma glucose concentration (1h-PG) during an oral glucose tolerance test (OGTT). This is the blood glucose level measured exactly one hour after a patient consumes a glucose solution.
According to the International Diabetes Federation (IDF), a value of ≥ 155 mg/dl in the 1h-PG test is an early indicator of impaired glucose regulation, often before fasting or two-hour values become abnormal. The hope is that this measurement could help identify at-risk individuals early on and allow for targeted treatment.
The Tübingen Lifestyle Intervention Program (TULIP) put this hypothesis to the test. Over nine months, researchers closely monitored 317 individuals with varying glucose tolerance levels. The goal of the lifestyle intervention was to achieve a weight loss of at least 5% through a balanced diet and regular exercise.
Participants were divided into three groups based on metabolic parameters:
- Normal glucose regulation
- Isolated elevated 1-hour prostaglandin (other values, such as fasting glucose and 2-hour prostaglandin, were normal)
- Classic impaired glucose regulation (prediabetes)
At the beginning of the study, it became clear that individuals with high 1-hour prostaglandin levels were metabolically in an intermediate state between healthy and unhealthy. Their insulin sensitivity and beta-cell function were impaired, and they had elevated liver and abdominal fat levels, but these were still reversible.
After nine months of intervention, the 1h-PG group saw significant improvements in insulin sensitivity and beta-cell function, restoring them to levels comparable to metabolically healthy individuals. At the same time, liver fat levels normalized. These improvements were much less pronounced in the prediabetes group.
The long-term benefits were impressive: individuals with elevated 1-hour glucose levels who participated in the intervention had an 80% lower risk of developing type 2 diabetes compared to people with prediabetes. Almost half even achieved normal blood glucose levels (normoglycemia), twice as many as in the prediabetes group.
"Weight loss and reduced liver fat improved both insulin sensitivity and the ability of beta cells to respond to glucose. This normalization of key metabolic processes could be crucial for enabling the transition to stable, healthy glucose metabolism," says Yiying Wang, the first author of the study and a MD student in the Department of Diabetology, Endocrinology and Nephrology of the University Hospital Tübingen and a Clinician Scientist in the DZD.
This new prevention strategy has practical potential. The one-hour glucose value proved to be the most sensitive marker for the early detection of impaired glucose tolerance. It was significantly more informative than the HbA1c value, fasting glucose, or two-hour glucose. "This value apparently marks the optimal point in time to normalize metabolism," comments Prof. Dr. Andreas Birkenfeld, the senior author of the study.
Birkenfeld suggests that this test could potentially enable the early identification and effective treatment of at-risk individuals, long before prediabetes is diagnosed. This could establish the 1-hour post-load glucose (1h-PG) as a new, clinically relevant biomarker.
So, what do you think? Could this be a game-changer in diabetes prevention? We'd love to hear your thoughts in the comments!
