pillar  10

Preventive and Public
Health

Why the Best Treatment Is the One You Never Need
Pillar 10 of 12 | Reading Time: 18 minutes
 
 
 

content last reviewd: january 2026

Based on peer-reviewed research available at time of publication. Medical science advances continuously. Always consult a qualified healthcare provider for personalised medical advice.

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the smartest medicine no one talks about

There is a form of medicine that gets very little attention.
It does not make dramatic headlines.
It does not involve exciting new technology.
It does not require a hospital or an expensive procedure.
But it saves more lives than almost any other medical intervention on earth.

 

An intervention simply means an action taken to improve a situation or outcome.
This form of medicine is called prevention.
The World Health Organisation estimates that at least 80 per cent of premature heart disease, stroke, and type 2 diabetes cases could be prevented.

 

Premature means happening earlier than it should, before a person has lived a full, healthy life.
Not treated after they arrive.
Prevented before they do.
Think about that for a moment.
Eight out of ten people who die too early from those conditions did not have to.
 
Every year, millions of people undergo, which means go through, heart surgery, dialysis, which is a medical procedure that cleans the blood when the kidneys cannot, chemotherapy, which is powerful medication used to treat cancer, and amputation, which means the surgical removal of a limb, for conditions that the evidence shows were substantially preventable.
Prevention does not just save lives.
It preserves the quality of those lives.
The difference between dying at 55 from a heart attack and living actively until 85 is not mostly genetics.
It is mostly choices made daily over decades.
And it is access to the right information at the right time.
This pillar is about giving you that information.

a story about two men

 

Picture two men who went to school together.
Same teachers.
Same town.
Same general starting point in life.
Marcus is 52.
He has never had a full health check.
He does not know his blood pressure, which is the force of blood pushing against the walls of the blood vessels.
He does not know his cholesterol levels.
Cholesterol is a fatty substance found in the blood.
He has never been screened for bowel cancer despite being over 50.
Screened means checked for signs of a condition before any symptoms appear.
He has been meaning to book an appointment with his doctor for two years.
He feels fine, so he keeps postponing it.
Then one Tuesday morning he has a heart attack.
Moderate.
Not fatal.
But he spends a week in hospital.
He learns that his blood pressure had been significantly elevated, which means higher than the healthy range, for years.
His cholesterol was high.
His blood sugar was in the pre-diabetic range, which means higher than normal but not yet at the level diagnosed as type 2 diabetes.
None of it had produced obvious symptoms.
None of it had been picked up.
Because he had never been checked.
His old schoolfriend James is also 52.
He has had a health check every two years since his mid-forties.
His blood pressure was flagged as slightly elevated four years ago.
He made dietary changes and started walking every day.
It came down without medication.
His cholesterol was checked.
His blood sugar was checked.
He completed his bowel cancer screening when it was offered.
All clear.
He does not take his health for granted.
He treats his annual check as seriously as he treats his car’s MOT.
The MOT is the annual safety inspection required for vehicles in the United Kingdom.
A car that is never checked eventually breaks down.
Often at the worst possible moment.
The body works the same way.

THE THREE LEVELS PF PREVENTION

Not all prevention is the same.
There are three distinct levels.

 

Primary Prevention:

 

Primary prevention stops disease from developing in the first place.
Think of it as building a strong fence before the animal escapes.
It includes lifestyle choices like not smoking, eating well, moving regularly, sleeping adequately, and managing stress.
It also includes vaccinations, which are injections or treatments that train the immune system to recognise and fight specific diseases before they cause illness.
Primary prevention is the most powerful level.
It is also the one most within the control of the individual.

 

Secondary Prevention:

 

Secondary prevention catches disease early, before it has caused significant damage.
Think of it as spotting a small leak in the roof before it brings the ceiling down.
It includes health screenings and check-ups that detect, which means find, high blood pressure, elevated cholesterol, early cancer, and abnormal blood sugar before obvious symptoms appear.
Most serious diseases do not announce themselves in their early stages.
They develop silently.
Secondary prevention is the process of looking for them before they make themselves known.

 

Tertiary Prevention:

 

Tertiary prevention manages existing disease to prevent it from worsening.
Tertiary means third level or third in order.
Think of it as repairing the ceiling after the leak has happened and making sure it never collapses entirely.
It includes cardiac rehabilitation, which means a structured programme to help people recover after a heart attack, diabetes management to prevent complications, and physiotherapy, which means physical therapy to help restore movement and function, after a stroke.
All three levels matter.
But most people focus only on tertiary prevention, managing disease after it has already arrived, when the greatest opportunity lies in primary and secondary prevention.

the screenings that save lives

Health screenings are one of the most powerful tools in medicine.

 

A screening is a test done on people who appear healthy to find signs of a condition before symptoms develop.
They find the problems nobody knew were there.
Before those problems become life-threatening.
Here are the most important screenings for most adults.

 

Blood Pressure:

 

High blood pressure is sometimes called the silent killer.
It almost never produces symptoms.
But over years it silently damages arteries, which are the blood vessels that carry blood away from the heart, the heart itself, the brain, and the kidneys.
The NHS recommends that all adults get their blood pressure checked at least every five years.

 

Blood pressure is checked in minutes with a simple inflatable cuff placed around the upper arm.
Knowing your numbers is one of the most important pieces of health information you can have.

 

Cholesterol and Lipid Profile:

 

A lipid profile is a blood test that measures different types of fat in the blood.
Lipid is the scientific term for fat.
Elevated LDL cholesterol, which is the type sometimes called bad cholesterol because it contributes to the build-up of fatty deposits in blood vessels, quietly accumulates on artery walls over years.
Think of it like a slow narrowing of a pipe.
The water still flows.
Until the narrowing becomes critical.
And then it does not.
The NHS recommends that adults get a cholesterol check as part of their regular health assessment.

 

Blood Sugar:

 

Type 2 diabetes develops over years through a gradual process of insulin resistance, which means the body becoming less responsive to the hormone that manages blood sugar.
Most people with pre-diabetes, which means blood sugar higher than normal but not yet at diabetic levels, have no symptoms.
A simple blood test called a fasting blood glucose test, which measures blood sugar after not eating for several hours, or an HbA1c test, which measures the average blood sugar over the previous three months, reveals blood sugar levels.
HbA1c stands for haemoglobin A1c, which is a form of the protein in red blood cells that carries oxygen.
When blood sugar is consistently elevated, more glucose attaches to this protein, so measuring it gives a picture of blood sugar control over time.
Think of it like a three-month average rather than a single day’s snapshot.
Catching elevated blood sugar in the pre-diabetic range gives an enormous opportunity to reverse the process before it becomes type 2 diabetes.
The American Diabetes Association recommends screening for type 2 diabetes in all adults from age 35.

 

Bowel Cancer Screening:

 

Bowel cancer is one of the most common cancers in the world.
The bowel is the lower part of the digestive system, including the large intestine and the rectum, which is the final section before waste leaves the body.
When bowel cancer is caught early, it is one of the most treatable cancers.
The NHS bowel cancer screening programme invites adults between 50 and 74 to complete a home stool test every two years.
A stool test means a test on a small sample of your bowel movements.
The test looks for tiny traces of blood in the stool.
Blood in the stool can indicate the presence of polyps, which are small growths on the inner lining of the bowel.
Most polyps are harmless.
But some can develop into cancer over years if left untreated.
Removing them early removes the risk entirely.
If you receive your screening invitation, complete it.
It takes minutes.
It could save your life.

 

Breast Cancer Screening:

 

The NHS breast screening programme invites women between 50 and 71 for mammography, which is a type of X-ray of the breast, every three years.
Mammography can detect tumours, which are abnormal growths, before they can be felt by hand.
When breast cancer is found at stage 1, which is the earliest stage when the tumour is small and has not spread, the survival rate is over 90 per cent.
When found at stage 4, which is when the cancer has spread to other parts of the body, the outlook is much more difficult.
Early detection, which means finding the cancer early, saves lives in the most direct and measurable way possible.

 

Cervical Screening:

 

The NHS cervical screening programme invites women between 25 and 64 for regular smear tests.
The cervix is the lower part of the uterus, which is the womb, where it connects to the vagina.
Cervical screening does not test for cancer.
It tests for changes in the cells of the cervix that could develop into cancer if left untreated.
Treating these changes before they become cancer is prevention at its most direct.

the vaccinations that protect communities

Vaccination is one of the greatest achievements in the history of medicine.

A vaccine is a treatment, usually given as an injection, that trains the immune system to recognise and fight a specific disease before it causes illness.

Smallpox, which was a deadly infectious disease that disfigured and killed millions throughout history, was declared eradicated, which means completely eliminated, in 1980 after a global vaccination campaign.

Polio, which is a disease caused by a virus that can cause paralysis, meaning loss of movement, has been eliminated from most of the world.

Yet vaccine hesitancy, which means reluctance or refusal to take vaccines, has allowed diseases that were nearly eliminated to return in communities where vaccination rates have fallen.

Think of community vaccination like a fire break in a forest.

A fire break is a gap in a forest that stops fire from spreading.

If enough of the forest has been cleared, a fire cannot spread.

It runs out of fuel.

This is called herd immunity.

Herd immunity means when enough people in a community are immune to a disease, either through vaccination or previous infection, that the disease cannot spread easily from person to person.

The vulnerable people in the community, the very young, the very old, and those with weakened immune systems who cannot be vaccinated, are protected by the vaccination of those around them.

The [WHO](https://www.who.int/news-room/fact-sheets/detail/immunization-coverage) estimates that vaccination prevents 3.5 to 5 million deaths every year.

For adults, important vaccinations include the seasonal flu vaccine, the COVID-19 booster as recommended, and shingles vaccination for adults over 70.

Shingles is a painful condition caused by the reactivation of the chickenpox virus in people who had chickenpox earlier in life.

Speak to your doctor or pharmacist about which vaccinations are recommended for your age and health status.

how chronic diseases develop

Understanding how chronic disease develops is one of the most empowering things a person can learn.
Chronic disease means a long-lasting health condition that develops over time rather than appearing suddenly.
Because the process is not sudden.
It is slow.
It is gradual.
And for most of its duration it is reversible.

Think of chronic disease like erosion.
Erosion is the process by which rock or soil is gradually worn away by wind, water, or other natural forces.
A river does not cut a canyon in a day.
A canyon is a deep valley with steep sides.
It carves it slowly over thousands of years.
Each day the change is invisible.
But the direction is consistent.
And over time the canyon is undeniable.

Cardiovascular disease, which means disease of the heart and blood vessels, begins with small injuries to the inner walls of arteries.
Inflammation, which is the body’s response to damage, moves in to repair them.
LDL cholesterol particles, which are the type that contribute to fatty deposits in blood vessels, accumulate at the site of inflammation.
Plaques begin to form.

A plaque is a build-up of fatty material inside a blood vessel.
Think of plaques as slowly forming blockages inside a pipe.
Over years the pipe narrows.
Blood flow is reduced.
One day, a plaque ruptures, which means breaks open suddenly.
A clot, which is a thickened mass of blood, forms.
The pipe blocks entirely.
A heart attack or stroke is the result.

This process begins in some people in their twenties and thirties.
It progresses silently for decades.
Without a single obvious symptom.
Until it is not silent anymore.
Type 2 diabetes follows a similar trajectory.
Trajectory means the path something follows over time.
Years of blood sugar spikes, insulin resistance, and elevated insulin produce damage to blood vessels, nerves, and organs long before a diagnosis is made.

Knowing this changes everything.
Because if the process starts decades before the crisis, the window for intervention is enormous.
The daily choices being made right now are either building those plaques or preventing them.
Either deepening the insulin resistance or reversing it.
Either driving the erosion or stopping it.

the lifestyle choices with the strongest preventive evidence

The evidence on prevention is consistent across thousands of studies and decades of research.
The same behaviours appear again and again as the most powerful protectors against chronic disease.

Not smoking:


Smoking is the single most preventable cause of premature death globally.
It causes 12 types of cancer.
It is the leading preventable cause of cardiovascular disease.
It causes chronic obstructive pulmonary disease, which is a serious lung condition that makes breathing progressively more difficult.
Stopping at any age produces real and measurable health benefits.

Maintaining a healthy body weight:


Obesity, which means carrying significantly more body fat than is healthy, is a significant risk factor, which means it meaningfully increases the likelihood, for cardiovascular disease, type 2 diabetes, several cancers, sleep apnoea, which is a condition where breathing repeatedly stops during sleep, joint disease, and early death.
Weight management is not primarily an aesthetic concern.
Aesthetic means relating to appearance.
It is a medical one.

Regular physical activity:


The WHO recommends 150 minutes of moderate activity per week as the evidence-based minimum.
Physical inactivity is one of the leading modifiable, which means changeable, risk factors for premature death globally.

A healthy dietary pattern:


A diet centered on vegetables, fruits, whole grains, legumes, which are foods like lentils, beans, and chickpeas, and quality protein with minimal ultra-processed food reduces the risk of cardiovascular disease, type 2 diabetes, and several cancers.
The Global Burden of Disease Study published in The Lancet estimated that poor diet is responsible for 11 million deaths per year globally.

Limiting alcohol:


Alcohol is classified as a Group 1 carcinogen by the International Agency for Research on Cancer.
A carcinogen is a substance that causes cancer.
Group 1 is the highest classification, meaning the evidence that it causes cancer in people is definitive, which means completely certain.
It increases the risk of at least seven types of cancer.
Reducing or eliminating alcohol reduces these risks proportionally, which means the more you reduce, the more the risk falls.

Managing blood pressure:


Hypertension, which is the medical term for high blood pressure, is the leading preventable risk factor for stroke and a major risk factor for heart disease and kidney disease globally.
Knowing your blood pressure and keeping it in a healthy range through diet, movement, and medication if necessary is one of the highest-impact preventive actions available.

wha public health actually is

Public health is health at the population level.
Population means all the people in a community or country.
It is the science and practice of protecting and improving the health of entire communities.

Think of individual medicine as treating one patient at a time.
Think of public health as changing the conditions that make populations of patients sick in the first place.
Clean water.
Safe food.
Vaccination programmes.
Workplace safety regulations, which means rules that protect workers from harm.
Air quality standards, which means rules about how clean the air must be.
Anti-smoking legislation, which means laws that restrict smoking in public places.
Road safety rules.
All of these are public health interventions.
All of them save lives at a scale that individual medicine cannot match.

The introduction of clean water and sewage systems in the 19th century prevented more deaths than all the antibiotics ever produced.
Antibiotics are medicines used to treat bacterial infections.
Not because antibiotics are not remarkable.
They are.
But because removing the conditions that made people sick in the first place is more powerful than treating people after they become sick.

the health inequalities nobody should accept

Prevention is not equally available to everyone.
And that is a fact that deserves honest attention.
People living in poverty have lower life expectancy, which means they tend to live fewer years.
Higher rates of chronic disease.
Less access to preventive care.
More exposure to environmental health hazards, which means harmful things in the environment like pollution.
Less time to prepare healthy food.
Less access to safe spaces for physical activity.
More chronic stress from financial insecurity, poor housing, and unstable employment.
All of these factors are health determinants.
A health determinant is anything that influences a person’s health.
And none of them are the fault of the individuals experiencing them.

The WHO defines the social determinants of health as the conditions in which people are born, grow, live, work, and age.
Social determinants means the social and economic factors that shape health.
These conditions are shaped by the distribution of money, power, and resources.

A person born into poverty faces a biological environment fundamentally different from a person born into comfort.
This is not acceptable.
And acknowledging it is not a political act.
It is a scientific one.

Health inequalities are measurable.
They are documented.
They are substantially preventable through policy, investment, and genuine societal commitment to the health of every member of society.
This site exists partly because of this reality.
Because the knowledge that prevents chronic disease should not be available only to people with the money to pay for good doctors.
It should be available to every person on earth.
Simply.
Honestly.
Free.

a personal prevention framework

Here are the most impactful preventive actions within reach of most people.

Know your numbers:


Blood pressure.
Cholesterol.
Blood sugar.
Body mass index, which is a measure of body weight in relation to height used to assess whether weight is in a healthy range.
Waist circumference, which is the measurement around the middle of the body.
You cannot prevent what you cannot measure.
Book a health check.
Know your starting point.

Complete your recommended screenings:


Bowel cancer screening.
Cervical screening.
Breast screening.
Blood pressure checks.
Cholesterol checks.
These exist because they save lives.
Use them.

Stay up to date with recommended vaccinations:


Flu vaccine each year.
COVID-19 boosters as recommended.
Shingles vaccination for those over 70.
Speak to your doctor about what applies to you.

Not smoking is the single most impactful preventive action available to a smoker:


If you smoke, the most powerful thing you can do for your long-term health is to stop.
The NHS Stop Smoking Service provides support that significantly improves quit success rates.

Move every day:


150 minutes of moderate activity per week.
21 minutes per day.
The single most evidence-based, universally accessible lifestyle intervention for chronic disease prevention.

Eat mostly whole food:


Not perfectly.
Mostly.
The majority of what you eat should be close to its natural form.

Limit or eliminate alcohol:


There is no safe level of alcohol from a cancer risk perspective.
Reducing it reduces risk proportionally.

Manage stress actively:


Chronic stress is not just unpleasant.
It is a measurable health risk.
Treat stress management as a medical necessity.

key takeaways

✓ The WHO estimates that at least 80 per cent of premature heart disease, stroke, and type 2 diabetes cases could be prevented through healthy lifestyle choices.

✓ Most serious chronic diseases develop silently over decades before producing obvious symptoms. Health screenings detect them during the window when intervention is most effective.
 
✓ The NHS Health Check is available every five years to adults between 40 and 74. It is one of the most valuable preventive health tools available.

✓ Vaccination prevents 3.5 to 5 million deaths every year according to the WHO.

✓ Poor diet is responsible for 11 million deaths per year globally according to the Global Burden of Disease Study published in The Lancet.

✓ Alcohol is a Group 1 carcinogen, which means a substance definitively proven to cause cancer, according to the International Agency for Research on Cancer. It increases the risk of at least seven types of cancer.

✓ Cardiovascular disease and type 2 diabetes begin developing decades before diagnosis. The choices being made today are either building or preventing that process.

✓ Health inequalities are real, measurable, and substantially preventable. They are shaped by social and economic conditions, not individual character.

✓ Know your numbers. Complete your screenings. Stay vaccinated. Do not smoke. Move daily. Eat mostly whole food. These are the foundations of personal prevention.

frequently asked questions

At what age should I start thinking about prevention?
Now.

Regardless of your age.
The processes that lead to cardiovascular disease and type 2 diabetes begin in early adulthood for many people.
Primary prevention, which means the lifestyle choices that stop disease developing in the first place, is relevant at every age.
Secondary prevention, which means screenings and check-ups that detect problems early, becomes particularly important from the mid-thirties onwards, or earlier if you have risk factors such as family history, obesity, or smoking.
There is no age at which prevention becomes irrelevant.
For smokers, stopping smoking is the most impactful single action available.

For non-smokers, the most impactful preventive actions are maintaining a healthy body weight, being physically active for 150 minutes per week, eating a predominantly whole food diet, knowing and managing blood pressure and cholesterol, and completing recommended health screenings.
The NHS recommends an NHS Health Check every five years for adults between 40 and 74.

Outside of formal checks, blood pressure should ideally be checked every one to two years.
Cholesterol should be checked every five years or more frequently if previously elevated, which means higher than the healthy range.
Blood sugar should be checked every three years in adults with risk factors.
Speak to your doctor about what frequency is appropriate for your specific situation.
Family history is a risk factor, which means it increases your likelihood of developing a condition.

It is not a sentence, which means it does not determine the outcome.
Having a parent or sibling who experienced heart disease or type 2 diabetes increases your personal risk.
But the research is clear that lifestyle choices modify, which means change, that risk substantially.
Someone with a strong family history of heart disease who does not smoke, exercises regularly, eats well, and manages their blood pressure and cholesterol has a significantly lower risk than a family member with the same genes who does not do these things.
Family history is useful information.
It tells you where to pay closest attention.
It does not determine the outcome.
Preventive medicine is a specialised branch of medicine focused on preventing disease rather than treating it.

But the principles of prevention are relevant to everyone, not just specialists.
Every doctor has a role in preventive care.
And every person has the ability to apply preventive principles to their own daily life.
The most powerful preventive interventions, not smoking, being physically active, eating well, sleeping adequately, managing stress, and attending regular screenings, require no specialist.
They require knowledge and consistent action.

medical references

World Health Organisation. (2023). Noncommunicable Diseases: Key Facts.
 
World Health Organisation. (2023). Immunization Coverage.
 
World Health Organisation. (2023). Social Determinants of Health.
 
National Health Service. (2023). NHS Health Check.
 
National Health Service. (2023). High Blood Pressure (Hypertension).
 
National Health Service. (2023). High Cholesterol.
 
National Health Service. (2023). Bowel Cancer Screening.
 
National Health Service. (2023). Breast Screening (Mammography).
 
National Health Service. (2023). Cervical Screening.
 
GBD 2017 Diet Collaborators. (2019). Health Effects of Dietary Risks in 195 Countries. The Lancet. 393(10184):1958-1972.
 
International Agency for Research on Cancer. (2023). IARC Monographs on the Identification of Carcinogenic Hazards to Humans.
 
American Diabetes Association. (2022). Classification and Diagnosis of Diabetes. Diabetes Care. 45(Supplement 1):S17-S38.