A woman of fifty-four has a routine blood test and is told her HbA1c is 43. Not diabetes. Prediabetes. She is handed a leaflet about eating less sugar and told to come back in a year.
Nobody mentions that her waist has grown four inches in six years without her weight changing much, that she has lost muscle she did not know she had, or that both of those things are more relevant to that number than the sugar in her tea.
Metabolic risk changes in midlife. The question is what actually drives it, because the answer determines whether the leaflet is any use.
Type 2 diabetes becomes considerably more common in women after menopause. One study of 15,406 postmenopausal women found a prevalence of 12.7 per cent.
Timing matters too. Women who reach menopause before forty have roughly double the risk of developing diabetes compared with women who reach it between forty-five and fifty-four. That is a substantial difference, and it is one of the reasons early menopause is treated as a medical event rather than an inconvenience. Early menopause before 45 covers the wider implications.
So the association is real. What causes it is more interesting, and more useful.
Here is where honest coverage separates from the rest, because the evidence is genuinely contested.
The obvious story is that falling oestrogen directly causes insulin resistance. Oestrogen does influence how your body handles glucose, and removing the ovaries from animals produces insulin resistance reliably.
But the largest study following women through the transition, SWAN, suggested something less tidy: the changes in glucose handling seen around menopause track chronological ageing rather than the menopause itself. Women get older, and glucose handling changes with age in both sexes.
Studies attempting to separate the two have produced conflicting results, and the field acknowledges this openly.
Why does this matter to you rather than to researchers? Because if oestrogen were the direct cause, replacing it would be the obvious answer. If body composition is doing most of the work, the answer is something else entirely, and it is something you control.
Two changes happen through midlife, and both impair insulin sensitivity regardless of what oestrogen is doing directly.
Visceral fat increases. As oestrogen falls, fat redistributes from hips and thighs to the abdomen, including the fat packed around your organs. That fat is metabolically active in a way subcutaneous fat is not: it releases inflammatory signals and free fatty acids that directly interfere with insulin signalling. Why weight gathers around your middle covers the mechanism.
This is why your waist tells you more than your weight. A woman whose scales have not moved in five years but whose waist has grown three inches has undergone a meaningful metabolic change.
Muscle mass falls. Skeletal muscle is where most of the glucose in your bloodstream is disposed of. It is, in a real sense, your glucose sink. Lose muscle through your forties and fifties and you have less capacity to clear glucose, which means higher circulating insulin to do the same job.
The endocrine literature is explicit that increased visceral fat and decreased lean mass together impair insulin sensitivity, and that these body composition changes predispose women to type 2 diabetes after menopause independent of oestrogen deficiency.
Read that again, because it is the practical heart of this. The two biggest drivers are things you can change.
The standard prediabetes conversation is about sugar and weight. Both matter, and both miss what is specific to midlife.
Cutting sugar without addressing muscle leaves the glucose sink shrinking. You can eat well and still lose metabolic capacity every year.
Losing weight through restriction alone costs muscle alongside fat, which is precisely backwards. A woman who diets down four kilograms and loses two of them as lean tissue has improved a number and worsened the mechanism. Losing weight in menopause covers why this backfires repeatedly.
Watching the scales rather than the waist misses the redistribution entirely, which is the change that actually matters here.
Most women get an HbA1c and nothing else, which tells you where you are but not where you are heading.
HbA1c gives your average glucose over about three months. Under 42 mmol/mol is normal, 42 to 47 is prediabetes, 48 or above suggests diabetes.
Fasting glucose and fasting insulin together. This is the useful addition, and it is rarely offered. Insulin resistance develops years before glucose rises, because your pancreas compensates by producing more insulin. Glucose stays normal while insulin climbs, and by the time glucose rises the process has been running for a long time. Fasting insulin catches it early; HbA1c alone does not.
With both numbers you can calculate HOMA-IR, and our free insulin resistance calculator does the arithmetic.
Waist measurement. More informative than weight or BMI in midlife, because it reflects the fat that matters. Keeping your waist under half your height is the simplest useful target, and the waist-to-height tool takes thirty seconds.
Lipids and blood pressure, because insulin resistance rarely travels alone.
A reasonable request: "Could we check fasting insulin alongside glucose? I understand insulin resistance shows up there before it shows in HbA1c."
Resistance training, twice a week. This is the intervention that directly rebuilds the glucose sink, and it improves insulin sensitivity independently of weight loss. If you do one thing from this article, do this one. Strength training in midlife covers how to begin.
Protein at every meal. Around 1.2 to 1.6 grams per kilogram of body weight daily, spread across the day. Without it, the training cannot build anything.
Walking after meals. Ten to fifteen minutes after eating measurably blunts the glucose rise, because working muscle takes up glucose without needing insulin. It is unglamorous and it works.
Sleep. A few nights of poor sleep measurably reduce insulin sensitivity in healthy people. If night sweats are wrecking your sleep, treating them is a metabolic intervention. How hormones hijack your sleep.
Alcohol. Energy without fullness, plus disrupted sleep, plus impaired glucose handling the following day.
This is where it becomes interesting, and where overstating it would be easy.
A meta-analysis of randomised trials covering more than 29,000 participants between 1998 and 2024 found that hormone therapy significantly reduced insulin resistance in healthy postmenopausal women without existing metabolic disease. A 2025 review of 17 randomised trials reached the same conclusion.
The effect appears larger in women who already have diabetes. An earlier meta-analysis found HRT reduced insulin resistance by around 30 per cent in women with diabetes, against roughly 13 per cent in women without.
Now the necessary caveats, because they are the difference between information and marketing.
HRT is not licensed or recommended for preventing diabetes. No guideline recommends starting it for metabolic reasons alone, and improved insulin sensitivity is a welcome side effect rather than an indication.
Timing appears to matter, as it does for cardiovascular outcomes, with benefit concentrated in women starting close to menopause.
Route matters. Transdermal oestrogen bypasses first-pass liver metabolism and carries a lower clot risk than oral, which is relevant for women who already have metabolic risk factors.
The honest summary: if you are taking HRT for symptoms, a metabolic benefit is a reasonable bonus. If you are considering it purely for glucose, the evidence does not yet support that decision. The truth about HRT research covers the wider picture.
Two groups need a word of their own.
Women with PCOS arrive at menopause with insulin resistance already established, which raises the stakes on everything above. PCOS explained covers the underlying picture.
Women with type 1 diabetes face a particular gap: they tend to reach menopause earlier, insulin requirements often change through the transition, and the evidence on HRT in this group is genuinely sparse. Current guidance suggests an individualised approach with transdermal oestradiol preferred. If this is you, it is worth having your diabetes team and menopause prescriber in the same conversation.
And for anyone on GLP-1 medication, the interaction with hormones is its own subject. GLP-1 medications and women's hormones covers what to know.
Diabetes risk rises after menopause, and the reason is less mysterious than it sounds. Fat moves inward, muscle quietly disappears, and together those two changes reduce your ability to handle glucose.
The mechanism is why the usual advice about sugar falls short, and why the most useful thing you can do is not dietary at all. Rebuilding the muscle rebuilds the capacity.
And if your last blood test said prediabetes, that is not a sentence. It is the earliest useful warning you will get, and it arrives at the point where the changes that matter are still entirely within reach.
Does menopause cause type 2 diabetes?
It is associated with higher risk, but the mechanism is contested. The largest cohort study suggested glucose changes track ageing rather than menopause itself. What is not contested is that increased visceral fat and lost muscle impair insulin sensitivity independently of oestrogen.
Does early menopause increase diabetes risk?
Yes. Women reaching menopause before forty have roughly twice the risk compared with those reaching it between forty-five and fifty-four.
What tests should I ask for?
HbA1c, plus fasting glucose and fasting insulin together. Insulin resistance appears in insulin years before it appears in glucose, so HbA1c alone catches it late. Add a waist measurement, lipids and blood pressure.
Does HRT reduce diabetes risk?
Trials show it significantly reduces insulin resistance, with a larger effect in women who already have diabetes. But it is not licensed or recommended for preventing diabetes, and no guideline suggests starting it for that reason alone.
What is the single most useful thing I can do?
Resistance training twice a week. Muscle is where most glucose is disposed of, and rebuilding it improves insulin sensitivity independently of any weight change.
Why does my waist matter more than my weight?
Because visceral fat around the organs drives insulin resistance in a way that fat under the skin does not. Your waist can grow while the scales stay still, and that change is the one that counts.
Sources: Salpeter SR et al., Meta-analysis: effect of hormone-replacement therapy on components of the metabolic syndrome in postmenopausal women, Diabetes Obes Metab 2006;8(5):538-54 · Mauvais-Jarvis F, Manson JE, Stevenson JC, Fonseca VA, Menopausal hormone therapy and type 2 diabetes prevention: evidence, mechanisms, and clinical implications, Endocr Rev 2017;38(3):173-88 · Meta-analysis of randomised controlled trials on hormone therapy and insulin resistance, 29,000+ participants, 1998-2024 · Slopien R et al., Menopause and diabetes: EMAS clinical guide, Maturitas 2018;117:6-10 · Educational only, not medical advice.
Keep reading: Why weight gathers around your middle · Strength training in midlife · The heart-health shift · PCOS explained · Free insulin resistance calculator · Take the free Hormone Quiz