How do I know if my blood sugar is healthy (prediabetes)?
Prediabetes can be measured reliably, but no single blood test provides complete certainty on its own. If in doubt, have multiple values measured and discuss with your doctor whether a lifestyle programme or medication is worthwhile, because that difference has been proven to matter.
Prediabetes is an intermediate stage in which your blood sugar is higher than normal, but not yet high enough to qualify as type 2 diabetes. There are three ways to measure it: a fasting blood sugar (100-125 mg/dL is the prediabetes range), an HbA1c measurement (a kind of 'three-month average' of your blood sugar; prediabetes falls between 5.7% and 6.4%), and an oral glucose tolerance test, in which you are tested after drinking a sugar solution. The problem is that there is no international consensus on which test is best, and the three tests sometimes identify different groups of people.
Moreover, fasting blood sugar and HbA1c are not without flaws. Compared with the oral glucose tolerance test, fasting blood sugar measurement overestimates prediabetes by about 25%, and HbA1c by about 10%. This means that some people who appear to have 'prediabetes' based on those tests score normally on the tolerance test. Conversely, at the conventional cut-off value, HbA1c misses about half of people with undetected full diabetes. No single test, therefore, ever gives the complete picture.
Prediabetes is not a neutral finding to be ignored. Without making any changes, approximately 10% of people with prediabetes in the US develop actual diabetes each year. Prediabetes is also associated with a greater risk of cardiovascular disease and mortality, although these are associations rather than proven causal relationships.
What you can concretely do about it is well supported by evidence. Eating less, exercising for at least 150 minutes per week, and active coaching reduced the risk of diabetes in research by 6.2 cases per 100 person-years over three years. That is more than medication: metformin achieved 3.2 cases per 100 person-years. Metformin works best in specific groups, namely women with a prior history of gestational diabetes, people under 60 with a BMI of 35 or higher, or those with somewhat more elevated blood sugar values (fasting blood sugar above 110 mg/dL or HbA1c of 6.0% or higher). Whether the evidence for lifestyle intervention also applies to people with a normal weight or exclusively a slightly elevated fasting blood sugar remains unclear, because most studies were conducted in people with excess weight.
Based on two meta-analyses, multiple reviews, and several studies not further indexed. Diagnostic accuracy and risk figures are robustly described; progression and interventions have been examined in randomised research (Diabetes Prevention Program and related studies), although the representativeness of the study populations is sometimes open to question.
What does stable blood sugar do for healthy ageing?
A stable, low blood sugar is associated worldwide with more healthy life years. The association is clear, but the exact gain per individual cannot be quantified on the basis of this research.
Is a glucose meter useful if you don't have diabetes?
Without diabetes, a glucose monitor gives you some genuinely interesting information about how your body responds to food, exercise and stress. But that monitoring actually leads to better health has not yet been demonstrated.
How do you measure insulin resistance?
There is no single best method for everyone: the clamp is the most accurate but is only feasible in a specialised setting. For practical use, HOMA or QUICKI from a fasting blood draw are a reasonable starting point, provided the result is compared against population-specific norms.
Does eating a lot of sugar give you type 2 diabetes?
Sugary drinks clearly and demonstrably increase your risk of type 2 diabetes. Sugar from solid food barely does. The biggest difference comes from drinking fewer sugary drinks, exercising more and losing weight.
What is a healthy HbA1c value?
There is no fixed 'healthy' HbA1c value: lower within the normal range appears to be better, but how low is optimal also depends on your personal circumstances. Discuss your result with your doctor if you are pregnant or have risk factors.
What does your HbA1c tell you about your risk of diabetes and ageing?
An elevated HbA1c, even well below the official diabetes threshold, is associated with a greater risk of diabetes, kidney damage, eye complications and possibly dementia. Have your HbA1c checked regularly and discuss with your doctor what a healthy target value is for you.