Can your HbA1c also be too low?
An HbA1c below 5.0% is associated with an increased risk of death in people without diabetes, although this is likely a signal of an underlying condition. Always have a strikingly low value investigated by your doctor.
HbA1c is a measure of how high your blood sugar has been on average over the past two to three months. Most attention goes to values that are too high, but a study among people without diabetes shows that a very low value (below 5.0%) is also associated with a higher risk of death. Compared with a value in the middle range (5.0-5.7%), that risk was 30% higher in the short term and 12% higher over ten years. This is a statistical association, not a proven causal relationship. A low value may therefore reflect an underlying condition rather than cause harm itself.
One indication of this comes from brain injury research. An analysis of tens of thousands of lab results showed that brain injury was the only condition in which HbA1c was consistently lower than in healthy individuals. In all 35 other disease categories examined, HbA1c was either elevated or within normal range. A low HbA1c can therefore sometimes be a signal that something else is going on in the body.
In addition, a low measurement can simply be unreliable. Certain conditions or medications, such as an autoimmune disease combined with specific drugs, can interfere with the measurement so that the result appears much lower than the actual blood sugar level. In such a case, a different test, such as fructosamine, is a better option. This comes from a case report, so it is a rare situation, but it does show that a strikingly low result always deserves closer examination.
Finally, there is an observational study in pregnant women suggesting that a low-normal HbA1c reduces the blood sugar buffer. In mothers with an HbA1c below 5.6%, severe gum disease was associated with a one-and-a-half to two times higher chance of having a baby with a low birth weight. In mothers with a slightly higher value, that association disappeared. What explains this mechanism is not yet clear; the study is purely observational and was conducted in a specific Brazilian study population.
All claims are based on associational research (no RCTs). The mortality figures come from one larger study (PMID 33378417). The brain injury research is a large laboratory analysis (PMID 30905458). The falsely low measurement and the pregnancy finding are respectively a case report and an observational study (PMID 34611711, 34792204).
How do you lower a high HbA1c?
Several medications demonstrably lower HbA1c: the weekly semaglutide injection has the strongest evidence base, but oral combinations involving empagliflozin or semaglutide also offer good evidence. Discuss with your doctor which option suits your situation, side-effect profile and reimbursement coverage.
What is a healthy HbA1c value?
In healthy adults, a normal HbA1c falls between roughly 4.79% and 6.15%, with an average of 5.47%. If your value is above this, discuss it with your general practitioner to rule out prediabetes or diabetes.
How often should you have your HbA1c measured?
In stable diabetes, measuring twice a year is standard; when values fluctuate or treatment has changed, four times a year is the norm. Discuss the frequency that suits you best with your doctor.
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.
Why is it harder for me to lose weight than it used to be?
Ageing lowers your energy expenditure through muscle loss and a slower metabolism, making weight loss objectively harder. Strength training two to three times per week is the best-supported way to slow that process and support weight loss, ideally with professional guidance.
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.