Pre-Diabetes: More Than a Number

One line makes the difference

Worldwide, about one in ten adults has diabetes. In Hong Kong, among people aged 15 to 84 living outside institutions, about 8.5% have diabetes or high blood glucose, according to the 2020–22 Population Health Survey. Roughly a third of that group (3.1% of the whole population) did not know it before the survey. The same survey found another 1.6% already had fasting glucose above normal, between 6.1 and 6.9 mmol/L: pre-diabetes.

When the body-check report comes back, most people only look at the lines marked in red. Seeing a slightly high glucose reading, the usual reaction is: nothing to worry about yet, come back next year. But pre-diabetes isn’t really a question of “yet” or “next year.” It’s a question of whether you take the chance to reverse it, while you still can.

What the numbers actually mean

Pre-diabetes is not one test. It is any of three:

• Impaired fasting glucose — a fasting level of 6.1 to 6.9 mmol/L by the WHO definition, or 5.6 to 6.9 mmol/L by the American Diabetes Association.
• Impaired glucose tolerance — a glucose of 7.8 to 11.0 mmol/L two hours after a 75g oral glucose tolerance test.
• HbA1c of 5.7% to 6.4%.

It’s worth noting that two authoritative bodies don’t agree on where the cut off for Pre-diabetes on fasting-glucose line sits. That’s because these lines are drawn from long-term statistics and statistics can’t cleanly separate “normal” from “not normal” for everyone. A cut-off is a “number” but the body doesn’t work like a machine with one clean line; it’s dynamic. Pre-diabetes reflects the functioning of one particular person’s pancreas.

More than a number

What the report doesn’t show you is the day-to-day work of your pancreas.

The body keeps blood glucose steady to keep itself running. After eating, energy from food is stored away; between meals, that stored energy is released again. In simple terms, this is the job of two hormones — insulin and glucagon. Insulin, secreted by the pancreas, controls glucose levels so eating doesn’t send them swinging up and down. When insulin secretion falls short, or the body’s cells stop responding properly to it, glucose rises — and can stay raised for a long time.

By the time a fasting glucose reads 6.2, that process has been underway for years. The cells have already become resistant. The pancreas has already been compensating — working harder, secreting more, to keep the number looking almost normal. The number is the last thing to move, not the first.

This also explains a common misunderstanding. Many people assume high blood glucose comes from eating too many sweet things. It doesn’t work that way — excess weight, especially around the abdomen, makes cells less responsive to insulin, so you don’t need to eat much sugar for glucose to climb. And it’s rarely glucose alone: people at this stage often carry central obesity, abnormal lipids and raised blood pressure together i.e. metabolic syndrome. Large studies have found that many patients with heart disease turn out to be in the pre-diabetic range already which means coronary atherosclerosis often forms before diabetes is ever diagnosed.

So pre-diabetes isn’t a term doctors invented to scare you. It marks a real stage in a real process. High blood glucose is more than a number — it reflects the body’s reduced ability to control how it stores energy.

What happens if nothing changes

Each year, 5% to 10% of people with pre-diabetes go on to develop diabetes. Roughly a quarter convert within three to five years. Around 70% eventually do. University of Hong Kong showed that local data put the ten-year risk at about six times that of someone with normal glucose.

Read those figures as risk, not as fate. Seventy percent is not everyone. The number that matters is the one you can still change.

Who should be checking

You are at higher risk if you are over 45, overweight or obese, physically inactive, or have a parent or sibling with diabetes. Also if you have had gestational diabetes or delivered a baby over 4kg, or if you already have heart disease, stroke, high blood pressure, or polycystic ovary syndrome.

If any of these apply, blood glucose should be checked at least once a year, and sooner if your condition changes. Track your body weight and your other parameters at the same time. One reading in isolation says much less than a direction of travel.

The crucial difference is reversal

Diabetes, once established, is usually managed. Pre-diabetes can still be reversed. With early attention, blood glucose in pre-diabetes has a genuine chance of returning to a normal healthy level.

This is the golden period, not just about the numbers, for reducing the strain on your pancreas and improve how cells in your body respond to insulin. The ultimate aim is to restore the system to a state that the organ potentially maintain its function as long as possible. Chinese medicine has a phrase for this: 上工治未病, claiming that the superior physician treats the illness that has not yet appeared. Treating early, before the disease declares itself, is exactly what this stage offers.

That comes from change not from a pill. Sustained change about your mindset, weight and movement. This is not something extra to be done or some target to be achieved; it is about restoration, restore back to the state that your body should have been.

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Sources

1. Hong Kong prevalence — Department of Health (HKSAR), Population Health Survey 2020–22: adults 15-84, non-institutionalised — diabetes/high blood glucose 8.5%; undiagnosed diabetes 3.1%; impaired fasting glucose (6.1-6.9 mmol/L) 1.6%
2. Progression to diabetes — Diabetes Care 2007;30:753-759 — 5-10% per year progress to diabetes; ~25% within 3-5 years; ~70% eventually
3. Ten-year risk — University of Hong Kong data — 10-year risk of progression to diabetes approximately 6 times that of normoglycaemic individuals
4. Diagnostic criteria — WHO: IFG 6.1-6.9 mmol/L; ADA: IFG 5.6-6.9 mmol/L; IGT: 2-hour glucose 7.8-11.0 mmol/L after 75g OGTT; ADA: HbA1c 5.7-6.4%
5. Lancet — Global, regional, and national burden of diabetes from 1990 to 2021, with projections of prevalence to 2050: a systematic analysis for the Global Burden of Disease Study 2021. thelancet.com — 529 million people living with diabetes worldwide in 2021; projected to exceed 1.31 billion by 2050. Type 2 diabetes accounted for 96.0% of cases; 52.2% of global type 2 diabetes DALYs attributable to high BMI.
6. WHO — Diabetes fact sheet — a healthy diet, regular physical activity, maintaining a normal body weight and avoiding tobacco use are ways to prevent or delay the onset of type 2 diabetes.