INTERSTROKE: The Study That Proved we can change our Stroke risk

Nikhil Sharma
Jan 10
3 min read

Stroke Proof Risk Map based on Interstroke factors

For years, stroke has carried this unhelpful aura of inevitability.

People talk about it like it’s a lightning strike:

“It just happens… my dad was fine and then suddenly…”

But the INTERSTROKE project changed the conversation — permanently.

It didn’t just show that stroke is often preventable (we suspected that). It showed something much more useful:

✅ stroke risk is predictable✅ stroke risk is measurable✅ stroke risk is modifiable

And when you know what drives risk, you can do something about it.

What was INTERSTROKE?

INTERSTROKE was a huge international research project designed to answer a very practical question:

What are the biggest modifiable causes of stroke worldwide?

It was a large standardised case-control study across multiple continents — including low and middle-income countries — where:

cases = people admitted with their first-ever stroke
controls = people without stroke matched from the community/hospital setting
participants underwent the same structured risk assessment
stroke diagnosis was confirmed using routine neuroimaging

This matters, because it means INTERSTROKE isn’t based on vague data. It’s “real world”, global, and properly designed.

Why INTERSTROKE was a game changer

INTERSTROKE concluded something that I still find incredible:

A small cluster of risk factors accounts for ~90% of the population attributable risk of stroke.

In plain English:

If you tackle these major drivers, you can dramatically lower your odds of stroke — regardless of your age, sex, ethnicity, or country.

That’s why I call it the stroke prevention playbook.

Not theory. Not hype. Not “wellness”.

A manual to prevent a devastating condition.

The Top 10 Stroke Risk Factors (Ranked by Odds Ratio)

INTERSTROKE didn’t just list risk factors — it quantified them.

Below are the Top 10 key modifiable stroke risk factors, in approximate order by odds ratio (i.e., how strongly each is associated with stroke).

Important note: Odds ratios vary slightly by region, age, and stroke subtype (ischaemic vs haemorrhagic), but these are the headline drivers globally.

1) High blood pressure

This is the biggest factor.

High BP damages the lining of arteries, accelerates atherosclerosis, and directly drives:

intracerebral haemorrhage
lacunar strokes
vascular cognitive impairment

If you do one thing for stroke prevention, make it this:

Treat blood pressure like your number one brain-health biomarker. Get it checked and if it is high speak to a doctor.

2) Smoking

Smoking is an arterial toxin:

promotes clot formation
raises BP
increases inflammation
damages endothelium

Stroke risk drops meaningfully after quitting — and continues falling over time.

3) Abdominal obesity (waist-to-hip ratio)

This is not about weight stigma.

Central fat strongly tracks with:

insulin resistance
inflammation
dyslipidaemia
hypertension

4) Poor diet

Diet was measured using a diet risk score.

Essentially more fruit and veg and less high fat foods were better for us.

5) Physical inactivity

A powerful protective factor in reverse.

Regular activity improves:

BP
insulin sensitivity
lipid metabolism
vascular function
inflammatory profile

Exercise is essential

6) Diabetes mellitus

Diabetes accelerates vascular ageing.

It drives:

small vessel disease
atherosclerosis
endothelial dysfunction

Worth noting: insulin resistance likely matters years before diabetes appears, which is why prevention clinics should measure it early.

7) High alcohol intake

Alcohol is dose-dependent - the more you drink the worse it is:

heavy intake raises BP
increases haemorrhagic stroke risk
worsens AF (irregular heart rate) risk

8) Psychosocial stress / depression

INTERSTROKE included psychosocial factors — and they mattered.

This is huge, because it validates what clinicians see daily:

chronic stress and depression aren’t “soft”
they’re biological
they change risk through BP, inflammation, sleep, alcohol, adherence, and metabolic effects

9) Cardiac causes (especially atrial fibrillation)

This is the “silent assassin” category.

AF is common, often asymptomatic, and highly treatable — yet missed constantly.

This is exactly why rhythm monitoring (and increasingly wearables) has a legitimate place in prevention.

10) Abnormal blood lipids (ApoB / ApoA1 ratio)

INTERSTROKE used apolipoproteins rather than total cholesterol.

That’s very modern, and clinically important:

ApoB = number of atherogenic particles
the ApoB:ApoA1 ratio tracks vascular risk better than LDL alone in many people

This is one reason longevity-style testing (ApoB, Lp(a)) can genuinely upgrade stroke prevention.

The Stroke-Proof message: your risk is not random

The power of INTERSTROKE is not the statistics.

It’s the psychology.

Because it tells us:

Stroke is not mainly about rare diseases, genetic bad luck, or medical mystery.

It’s mainly driven by:

blood pressure
smoking
metabolic health
diet and activity
alcohol
stress
treatable heart rhythm issues

And that means you can do something radical:

You can stop waiting.

You can stop hoping.

You can build your own protection.

The real “playbook” (what to do next)

If INTERSTROKE gives us the map, then Stroke-Proof is the journey plan.