A huge medical review of 400,000 patients reveals a quiet risk doctors see every day

Most people think a broken bone is simple.

You break it.
Doctors fix it.
You heal.

But for tens of thousands of patients, that final step never comes.

The bone simply… doesn’t heal.

And according to one of the largest medical reviews ever published, one everyday habit may more than double the risk.

The hidden problem doctors call “non-union”

When a bone breaks, the body starts a slow rebuilding process.

New bone forms.
Blood vessels grow.
Cells work for months behind the scenes.

Doctors expect healing within six months.

But in some patients, the process stalls completely.

The medical term is non-union.
The bone ends never fully join.

This often means:

• Ongoing pain

• Repeat surgery

• Metal plates that never come out

• Years of limited movement

So what makes this happen?

A massive review looked for answers

In 2021, researchers from Australia, South Korea, and China decided to look at everything.

Not one hospital.
Not one fracture.

Everything.

They analysed 122 previous medical studies, covering an extraordinary 417,767 adult patients with broken bones.

Their goal was simple:

👉 What factors make bones fail to heal?

One factor stood out immediately

When researchers compared patients, one group kept appearing in the worst outcomes.

Smokers.

Across different bones, different surgeries, and different countries, the pattern stayed the same.

Smokers were far more likely to experience non-union.

In fact, the numbers were stark:

• Smokers had about 2.5 times the risk of a broken bone never fully healing

• They also had much higher rates of deep surgical infection

This wasn’t a small difference.
It showed up again and again across studies.

Why would smoking affect bone healing?

Bones don’t heal in isolation.

They rely on:

• Blood flow

• Oxygen

• New vessel growth

• Cell signalling

Smoking is already known to affect circulation and tissue repair.

This review didn’t test why in a lab.

But it showed something doctors see in real life:
👉 Healing struggles more often in smokers.

What about alcohol?

Surprisingly, alcohol didn’t show the same clear effect.

When researchers compared drinkers and non-drinkers:

• The results were mixed

• No consistent increase in non-union was seen

That doesn’t mean alcohol is “safe”.

It means the evidence wasn’t as strong or as clear as smoking.

A small but important detail before surgery

The review also found something interesting about timing.

Patients who stopped smoking at least four weeks before surgery:

• Had lower rates of post-surgical infection

• Compared to those who kept smoking right up to surgery

It didn’t magically fix everything.

But the infection risk dropped.

That caught doctors’ attention.

Why this matters to patients right now

Every year, thousands of people leave hospital believing healing is guaranteed.

For most, it is.

But for others, recovery becomes a long, frustrating story of:

• “Why hasn’t it healed yet?”

• “Why do I still need surgery?”

• “Why does my bone look the same on scans?”

This study helps explain why outcomes differ, even when injuries look similar.

Why doctors take this seriously

This wasn’t a small study.
It wasn’t a guess.
And it wasn’t a headline based on one experiment.

It was published in EClinicalMedicine, part of The Lancet group — one of the most respected medical publishers in the world.

The findings came from real patients, not lab animals.

That’s why hospitals and surgeons pay attention.

The study at a glance

This table summarises selected observations only. Full details are in the original study.

The question many patients now ask

If healing depends on more than surgery…

What else quietly affects recovery that patients are never warned about?

Original study

The influence of smoking and alcohol on bone healing: Systematic review and meta-analysis of non-pathological fractures
Published in EClinicalMedicine (The Lancet group)
DOI: https://doi.org/10.1016/j.eclinm.2021.101179

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⚠️ Important disclaimer

This article is for general information only.
It is not medical advice and does not replace professional care or the original scientific paper.

If you want full detail, always read the original study directly.

Universities, researchers, and publishers mentioned are not affiliated with this article and ORIEMS FIT and do not endorse the article or our products.