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Preventive Health · Early Detection · Functional Testing

Nobody Gets Ill
Out of Nowhere.

Every heart attack, every cancer diagnosis, every autoimmune flare has a story that began years — often a decade or more — before the event that everyone calls "sudden." The data was there. The markers were moving. The window to intervene was open. Most people never knew because nobody looked — or looked at the wrong things, too late, with the wrong threshold for concern.

Stephen DuncanFDN-P MSc BSc · 37 years clinical practice
Reading time14 minutes
RelatedBlood chemistry · HOMA-IR · Homocysteine

The conversation we keep having

"Did you hear about so-and-so? Had a heart attack on Tuesday. Seemed absolutely fine. No warning at all."

I have heard some version of this sentence for 37 years. Sometimes it is a heart attack. Sometimes it is a cancer diagnosis — bowel, pancreatic, breast, prostate — delivered as though the tumour appeared overnight. Sometimes it is a stroke, a type 2 diabetes diagnosis, a multiple sclerosis flare, a lupus presentation. Always with the same quality of surprise. Always "no warning at all."

The surprise is understandable. But it is almost never accurate.

Chronic degenerative disease does not arrive without warning. It arrives without detected warning — which is a different problem entirely. The warning was present in the data. The HOMA-IR was elevated seven years before the diabetes diagnosis. The homocysteine was climbing five years before the cardiac event. The hsCRP was persistently above 3.0 for a decade before the autoimmune flare. The HbA1c was 38 at 50, 41 at 54, 46 at 57. The dam was building pressure the whole time.

What people call "sudden" is almost always the moment the dam bursts — not the moment it started filling.

The pressure build-up — what a ten-year metabolic trajectory looks like
Age 40
Age 43
Age 46
Age 49
Age 52
Age 55
Age 58 · EVENT
Metabolic dysfunction accumulates gradually and largely silently. The cardiac event at 58 that "came from nowhere" was building for 18 years. The person who tested at 40 and 45 and 50 had three opportunities to redirect the trajectory. None of them were taken — not because the will wasn't there, but because the right markers weren't measured and the results weren't read with early dysfunction in mind.

The cardiovascular example — a decade in plain sight

Let me walk through what a cardiovascular event trajectory actually looks like in functional blood chemistry. This is not a hypothetical. It is a composite of the clinical picture I have seen repeatedly across 37 years of practice — the markers that were available, the story they were telling, and the point at which conventional medicine would have intervened versus the point at which functional medicine would have.

40
Stage 01 · Early dysfunction · Compensated
Insulin is working harder than it should
Fasting glucose5.1 mmol/L · normal
Fasting insulin78 pmol/L · elevated functional
HOMA-IR1.8 · early resistance
Triglycerides1.4 mmol/L · borderline
HDL1.1 mmol/L · low-normal
hsCRP1.8 mg/L · early elevation
Symptoms: mild afternoon energy dip, slight weight gain around the middle, occasional brain fog. "Normal for my age."
NHS response: Glucose normal. Cholesterol checked, within range. "Everything looks fine — come back in 5 years."
44
Stage 02 · Progressive dysfunction · Still compensated
The pancreas is compensating — but the pressure is building
Fasting glucose5.4 mmol/L · rising
Fasting insulin105 pmol/L · significantly elevated
HOMA-IR2.5 · moderate resistance
HbA1c37 mmol/mol · high-normal
Homocysteine11.2 µmol/L · elevated
hsCRP2.9 mg/L · approaching concern
Triglycerides1.9 mmol/L · elevated
Symptoms: sleep worsening, fatigue more persistent, waist measurement up 3 inches over 4 years, some joint stiffness in mornings.
NHS response: HbA1c still below 42 — not pre-diabetic. Cholesterol checked — total acceptable. "Watch your diet and exercise more." Homocysteine not measured.
48
Stage 03 · Established dysfunction · Endothelial damage underway
The vessel walls are now being damaged
Fasting glucose5.7 mmol/L · pre-diabetic by some criteria
HbA1c41 mmol/mol · upper edge of "normal"
Homocysteine14.8 µmol/L · significantly elevated
hsCRP4.2 mg/L · established elevation
ICAM-1elevated · endothelial activation
Lipoprotein(a)elevated · if ever measured
TG:HDL ratio2.8 · atherogenic pattern
Symptoms: blood pressure now 138/88, shortness of breath on exertion, intermittent chest heaviness dismissed as stress. Sleep apnoea developing. Erectile dysfunction appearing.
NHS response: HbA1c still below 42 — not pre-diabetic. Blood pressure "a bit high — reduce salt." Statin considered if cholesterol rises. Homocysteine and ICAM-1 not on standard panel.
52
Stage 04 · Advanced dysfunction · Plaque establishing
The atherogenic process is now established
HbA1c45 mmol/mol · pre-diabetic
Fasting glucose6.1 mmol/L · pre-diabetic
Blood pressure148/94 · medicated
LDL cholesterolelevated · statin now prescribed
Homocysteine18.4 µmol/L · critically elevated
hsCRP6.1 mg/L · high risk
NT-proBNPearly elevation · cardiac stress
Symptoms: now on antihypertensive medication, starting statin. Fatigue described as "my new normal." Reduced exercise tolerance. Still told overall cardiac risk is "moderate."
NHS response: Pre-diabetes confirmed — lifestyle advice and 6-monthly monitoring. Statin started for LDL. Antihypertensive adjusted. Homocysteine still not measured. Risk calculator puts 10-year CVD risk at 12% — "not high enough for intervention."
56
Stage 05 · The dam bursts
The cardiac event that "came from nowhere"
Troponin Televated · myocardial injury confirmed
ECGST changes
The event. Hospitalised. Stent or bypass. "Such a shock — he seemed absolutely fine."
What happened in retrospect: 16 years of documented metabolic dysfunction across markers that were available but not connected. The homocysteine at 11.2 at age 44 — if it had been measured, if it had been addressed with methylfolate and B12, the endothelial damage trajectory changes. The HOMA-IR at 1.8 at age 40 — addressable with dietary change and targeted support while beta cells were still fully functional. The window was open for a decade and a half.

The "it won't happen to me" problem

There is a cognitive distortion that runs through this conversation that is worth naming directly. It is not denial exactly — most people intellectually accept that chronic disease is possible for them. It is something more like temporal distance: the consequences feel abstract and far away, while the effort of early investigation feels immediate and concrete.

The person at Stage 1 in the trajectory above is not ignoring the risk. They feel well. Their annual blood test came back normal. Their GP said everything looks fine. There is no signal in their lived experience that anything is wrong — because the compensatory mechanisms of the body are extraordinary at masking dysfunction until they can no longer maintain the compensation.

This is the tragedy of the conventional screening threshold model. It is calibrated to detect disease, not to detect dysfunction before it becomes disease. The NHS threshold for pre-diabetes is an HbA1c of 42 mmol/mol. An HbA1c of 41 is not pre-diabetic. An HbA1c of 38 is entirely normal. But the person whose HbA1c has moved from 32 to 35 to 38 to 41 over twelve years is not in stable health — they are in slow-motion metabolic deterioration, and every one of those data points was available to tell that story if someone had been looking for the trajectory rather than the threshold.

A single blood test tells you where you are. A series of blood tests tells you where you are going. The trajectory is almost always more informative than the snapshot — and the trajectory is almost always visible years before the threshold is crossed.

The window of reversibility

This is not a counsel of inevitability. It is the opposite. The reason the trajectory matters is precisely because intervention at Stage 1 or Stage 2 requires far less effort and produces far better outcomes than intervention at Stage 4 or Stage 5.

Window 01 · Wide open
Age 38–44 · Early insulin resistance
What's reversible: Everything. Insulin sensitivity fully restorable with dietary intervention, targeted support, and lifestyle change.
Effort required: Moderate. Dietary change, magnesium, berberine or myo-inositol, exercise protocol, sleep optimisation.
Time to improvement: 3–6 months to meaningful marker improvement.
What conventional medicine does: Nothing. All markers within normal range.
Window 02 · Closing
Age 44–50 · Progressive resistance + endothelial stress
What's reversible: Most of it. Insulin resistance addressable, endothelial inflammation reducible, homocysteine correctable with B-vitamin support.
Effort required: Significant. Requires sustained dietary change, targeted methylation support, anti-inflammatory protocol, and regular retesting.
Time to improvement: 6–12 months to meaningful marker improvement. 2 years for full trajectory change.
What conventional medicine does: Monitors. Sometimes advises lifestyle change. Rarely addresses homocysteine.
Window 03 · Narrowing
Age 50–56 · Established dysfunction
What's reversible: Much of it, with the right approach. But structural changes (early plaque, arterial stiffness) are less reversible than functional ones. Beta-cell function may be partially compromised.
Effort required: High. Medication may now be appropriate alongside nutritional and lifestyle intervention.
Time to improvement: 12–18 months to meaningful marker improvement. Structural changes take longer.
What conventional medicine does: Prescribes statins, antihypertensives. Monitors glucose. Rarely addresses root cause.
Window 04 · Crisis response
After the event
What's reversible: Secondary prevention is still meaningful. But the primary event cannot be un-had. Structural damage is permanent.
Effort required: Maximum. Multi-drug regime, significant lifestyle change, ongoing monitoring.
Where the NHS is excellent: Acute crisis management is world-class. The system is designed for this moment.
The honest observation: The ten years before this window cost far less — in money, in medication burden, in quality of life, in years — than the treatment of the event itself and its sequelae.

The markers that tell the ten-year story

Not all markers provide equal early warning. Some — total cholesterol, fasting glucose in isolation — are late-stage indicators that move only when the problem is well established. Others show dysfunction a decade or more before the conventional threshold is crossed. The difference between the two categories is the difference between a screening test and an early warning system.

Marker When it moves What it signals NHS routine?
Fasting Insulin 10–15 years early Beta-cell compensation for developing insulin resistance — the earliest measurable metabolic signal No — not routinely measured
HOMA-IR 10–15 years early Calculated insulin resistance index — requires fasting insulin and glucose both measured No — requires fasting insulin
Homocysteine 8–12 years early Methylation insufficiency, endothelial toxin — directly predicts cardiovascular events independent of cholesterol No — not on standard panel
hsCRP 5–10 years early Systemic low-grade inflammation — more predictive of cardiac events than LDL cholesterol in multiple studies Occasionally, not routinely
TG:HDL Ratio 5–10 years early Surrogate insulin resistance marker calculable from standard lipid panel — rarely calculated Data available — rarely calculated
HbA1c 3–8 years early Three-month glucose average — the trajectory matters more than the single reading Yes — but threshold too late
Lipoprotein(a) Genetic — present lifelong Independent cardiovascular risk factor affecting 20% of population — inherited, minimally diet-responsive No — rarely measured
ICAM-1 / VCAM-1 3–7 years early Endothelial activation markers — monocyte adhesion beginning, early atherogenesis No — specialist testing
NT-proBNP 1–5 years early Cardiac wall stress — ventricle under pressure before clinical symptoms emerge Only if symptomatic
Fasting Glucose Late — compensated for years Rises only when insulin can no longer maintain normoglycaemia — the dysfunction has been present for a decade Yes — standard
Total Cholesterol Poor early warning Weak independent predictor of cardiovascular events — the most-tested marker with the least early-warning value Yes — standard

Why the surprise persists

Given that this data is available, why does the "sudden" narrative persist? Several reasons, all worth naming.

The screening model is designed for population efficiency, not individual optimisation. Measuring fasting insulin on everyone at 40 would catch a significant proportion of early insulin resistance. It would also generate millions of results requiring follow-up. The NHS system is not resourced for that — and the intervention for early insulin resistance (dietary change, targeted supplements) is not a pharmaceutical product that generates prescribing data.

The threshold model reinforces binary thinking. Normal or abnormal. Diabetic or not diabetic. This or that. The actual clinical picture is continuous — there is no cliff edge between a HOMA-IR of 1.4 and 1.6, between a homocysteine of 9 and 11. The trajectory through those values tells the story. The thresholds hide it.

The "it won't happen to me" bias is universal and well-documented. Optimism bias — the tendency to believe negative events are less likely to happen to oneself than to others — is stronger in health contexts than almost any other domain. The person who smokes and knows smoking causes cancer, who carries excess abdominal weight and knows metabolic syndrome is a cardiovascular risk, who has poor sleep and knows sleep deprivation has cardiac consequences — that person still experiences genuine surprise when the event occurs. The knowledge coexists with the assumption of personal exemption.

The annual blood test creates a false sense of coverage. "I had my bloods done last year and everything was fine" is a sentence that closes the conversation in most social contexts. What it often means is: my fasting glucose was below 6.0, my total cholesterol was below 5.0, my thyroid was within range, my full blood count showed no anaemia. None of which measures fasting insulin, HOMA-IR, homocysteine, hsCRP, TG:HDL ratio, or any of the markers that tell the early-stage story.

The honest framing
The surprise is a measurement gap, not a biological mystery
When someone says a diagnosis came "out of nowhere," what they mean is: the markers they measured didn't predict it, the symptoms they noticed weren't connected to it, and the system they interacted with didn't have the framework to see it coming. None of that means it wasn't visible. It means it wasn't looked for with the right tools, at the right resolution, with the right clinical framework for interpreting early dysfunction rather than established disease.

What a different model looks like

The alternative is not expensive, not complicated, and not dependent on anything that doesn't already exist. It requires two things that conventional screening currently lacks: the right markers, and the willingness to interpret them as a trajectory rather than a threshold.

A comprehensive blood panel at 40 — including fasting insulin alongside fasting glucose (enabling HOMA-IR), homocysteine, hsCRP, TG:HDL ratio, and the full lipid subfraction picture including Lp(a) — tells a story that the standard NHS screen cannot. Repeated at 45, 50, and 55 with the same markers, it reveals direction of travel. A homocysteine that was 7.8 at 40 and is now 11.2 at 45 is not a stable finding — it is a trend requiring explanation and intervention. A HOMA-IR that was 1.2 at 40 and is 2.1 at 45 is not a number to reassure — it is an early warning to act on.

The intervention at that stage is not a pharmaceutical regime. It is targeted B-vitamin support for the homocysteine. It is dietary change and targeted metabolic support for the HOMA-IR. It is sleep optimisation, stress load reduction, anti-inflammatory dietary principles. These interventions are inexpensive, evidence-based, and highly effective when applied at Stage 1 or Stage 2. They are significantly less effective when applied at Stage 4 — and they cannot un-burst the dam.

The testing argument in one sentence

The most expensive test is the one that comes too late to change the outcome. A comprehensive blood panel at 40 costs a few hundred pounds and takes one blood draw. A cardiac catheterisation costs tens of thousands and requires hospitalisation. The NHS will pay for the second one. Most people will pay for the first one themselves only if someone explains that the second one is what happens when the first one doesn't happen early enough.

The connected picture

The cardiovascular trajectory above is one example. The same logic applies to every chronic degenerative condition. Autoimmunity — the zonulin, the anti-TPO antibodies, the antigliadin antibodies were elevated years before the Hashimoto's diagnosis. Cognitive decline — the homocysteine, the omega-3 index, the vitamin D, the insulin resistance were all visible before the memory complaints. Cancer — the chronic inflammation, the oxidative stress markers, the immune dysregulation were present in the terrain before the tumour.

None of this means that testing always prevents disease. Some processes are genetic, some are environmental, some are stochastic in ways no measurement can fully predict. The claim is not that testing is infallible. The claim is that the information is available, the window to act is open for longer than most people realise, and the surprise we experience at diagnosis is almost always — not always, but almost always — a failure of detection rather than evidence that nothing could have been detected.

This is what drives the Test, Don't Guess approach. Not the belief that testing resolves all uncertainty. But the conviction that acting with data is better than acting without it — and that the data, for most of the conditions that kill and disable people in middle age, is available years before the crisis.

Know where you are in the trajectory

A comprehensive blood panel — including fasting insulin, HOMA-IR, homocysteine, hsCRP, TG:HDL ratio, Lp(a), and up to 180 additional markers on the Randox Signature Female panel — gives you the early-stage picture that standard NHS screening does not. Interpreted as a trajectory, not just a snapshot.

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