Going from Infectious Diseases to Chronic Diseases: An Evolutionary Perspective

Heather Campbell
 min read

Going from infectious diseases to chronic diseases is due to evolution.

Going from Infectious Diseases to Chronic Diseases: An Evolutionary PerspectiveFor centuries, infectious diseases have been the greatest threat to humans.

As a whole, chronic conditions are increasing every year while infectious diseases are declining thanks to antibiotics. Nearly 75% of today’s deaths are caused by chronic diseases such as cancer, cardiovascular disease, dementia, and diabetes. Problems are starting at increasingly younger ages.

Major epidemics, such as the plague in the 14th century, impacted society that is difficult to overestimate.

People got up healthy, started feeling unwell during the day, and 2 to 3 days later had simply died.

Even more recently, after World War I, just under 100 million people died due to Spanish flu, making this terrible disease more deadly than the war itself.

Going from infectious diseases to chronic diseases: Introduction

Two things have ensured that this doom and gloom is behind us:

First breakthrough

The first epidemiological studies made it clear that the plague was spread around wells (which proved to be a significant source of infection).

That insight was the basis for numerous hygienic measures to reduce mass spread.

Consider the installation of toilets, sewers, regular hand washing, etc.

These lifestyle adjustments ultimately helped curb the outbreak (and associated disastrous consequences) of many infectious diseases.

Second breakthrough

The second breakthrough was the emergence of antibiotics. This allowed people to heal even if they did get sick.

The effect of antibiotics was nothing short of spectacular. It was truly a triumph for science and especially for pharmaceuticals.

The treatment was not only efficient but also extremely simple and inexpensive. It almost seemed too good to be true…

You feel sick, you go to the doctor, and he diagnoses an infection. He prescribes antibiotics, and after spending a few days in bed, you are cured.

In particular, our grandparents’ generation witnessed how this miracle pill could save people who were until then simply doomed to die..

Not surprisingly, faith in medicines grew a lot during that period, partly because other drugs also showed great promise.

Medicines became hugely popular in fighting infectious diseases

The model of infectious diseases, which could be cured efficiently and effortlessly by a simple pill, was so attractive that it became a standard model for our medicine.

Soon, the field of medicine was almost equated with medication.

The fact that a drug could be patented and sold provided an enormous boost that allowed drug use to soar.

It is also very tempting for doctors to finish a consultation with a prescription for some medication. After all, it implies that something can be done about the disease. And also, the patient is usually quite happy because they get value for money.

Antibiotics and how (not) to use them

Medicines continue to occupy a prominent place in medicine and health care today.

Yet their use is far from always rationally justifiable.

The fact that drugs are part of evidence-based medicine (i.e., efficacy has been demonstrated by robust scientific research) does not imply that their use is always scientifically sound.

Antibiotics are an excellent illustration of this!

A pill may work perfectly for specific conditions. However, the problem lies in the mass use of antibiotics for conditions where they are not needed.

The danger of antibiotic resistance of bacteria

Antibiotics are so lavishly prescribed and used for trivial conditions that many bacteria have become resistant to the drugs. For example, conditions for which they are either:

  • not needed (e.g., uncomplicated bronchitis), or
  • not helpful (e.g., for viral infections such as influenza).

As a result, unfortunately, we now have bacteria such as MRSA (better known as the hospital bacteria), which regular antibiotics can no longer control.

Moreover, the bacteria themselves become resistant, so this problem applies to all patients, not just those who have been prescribed too many antibiotics in the past.

Other drugs can also cause problems

In addition to antibiotics, there are numerous other drugs whose use is often problematic.

Sleeping and sedative drugs are excellent practical examples of this.

Those who take a sleeping pill regularly may find it easier to fall asleep. But whether this will make you better rested remains to be seen.

In fact, often, these drugs also alter sleep structure, reducing its quality, not to mention the various side effects.

For example, users (often elderly people with more fragile bones) are at a higher risk of falling and suffering bone fractures as a result.

On top of that, habituation often occurs in the user after only a few weeks, rendering them completely ineffective.

Once the habituation period has set in, sleep aids have only symbolic-ritual significance.

Purely biochemically, they don’t do anything anymore. However, the belief that they make one sleep well still makes people feel like they can’t live without them.

For example, scientific research shows that subjects barely notice when their sleep aids are replaced with fake pills (placebos).

When they were subsequently told that they had actually just been given fake pills and that they might as well stop, this met with vehement protest.

But we certainly do not want to diabolize medicines because they are critical in specific cases.

Medicines are very effective for specific conditions such as bacterial infections. Still, they do have their limitations for other, mainly contemporary conditions related to our lifestyle.

Therefore, there is a need for a different approach: a lifestyle modification as the first step to a healthier life.

Evolution from acute to chronic conditions

The great threat of germs to our health is now largely under our control. And yet, human mortality is still 100%.

In other words, whether you smoke often or not, or drink a lot of alcohol or not, eventually we all die. No one can escape death.

If not by an infectious disease, then perhaps by a non-infectious disease.

Acute conditions

Acute conditions are usually caused by infections.

Such acute diseases usually evolve rapidly. You get the symptoms, then the disease develops in a matter of hours or days, and then you heal (or don’t heal).

Common examples of this are a cold and the flu.

If infections are caused by bacteria, they are usually treatable with antibiotics, but this is certainly not always necessary and useful.

For example, when an infection is due to a virus, antibiotics do not help. But exceptionally, they may still be prescribed in high-risk patients to prevent bacterial infections.

Chronic conditions

Chronic conditions (also called non-communicable diseases) have a longer lead time (sometimes even several decades) before they manifest themselves.

Examples include cancer, diabetes, and arteriosclerosis.

Often (but not always), there are noticeable symptoms such as high blood pressure or insulin resistance (where one becomes less sensitive to insulin).

But even these symptoms are not immediately felt and often only come to light after a doctor’s visit.

Lifestyle plays an important role

Important fact: Lifestyle also plays a role in acute conditions such as infections.

For example, many bacteria have become resistant to our antibiotics through overuse and unnecessary use, once again causing people to die from conditions we used to be able to treat.

It’s actually kind of the same story as with our diet.

Medicines are generally very easily and readily available. Still, the consequences are not unavoidable when we reach for them too quickly and too often.

One reason, for example, is the pressure to continue working rather than taking time to rest.

A sensible goal for policymakers is to aim for much less antibiotic use to keep the problems of resistant bacteria to an absolute minimum.

In addition, our lifestyle also has a significant impact on our immune system. Indeed, suppose we adjust our lifestyles to prevent or cure chronic diseases. In that case, a side effect is that we are also less likely to contract infections.

Chronic diseases become more likely as we age. Still, the risk also becomes greater when our lifestyles deviate from the pattern we have been selected for over millions of years.

Let that be just the situation many people find themselves in today. Society is aging, and our way of life has changed (and is still changing) significantly.

Chronic conditions: Alarming figures

The proportion of chronic conditions is increasing year by year.

This alarming increase occurred mainly after World War II, not coincidentally the period when most infectious diseases became easily treatable with antibiotics.

Our lifestyles changed drastically in terms of diet, exercise, social contacts, and life also became a lot busier and more hurried.

Unfortunately, the consequences are now quite visible.

Related: Why Should We Avoid Ultra-Processed Foods? Risks and Consequences

Serious public health consequences

Nearly 75% of today’s deaths are caused by chronic (non-communicable) diseases such as cancer, cardiovascular disease, dementia, and diabetes.

Millions of Americans suffer from diabetes, which is still a rising trend. Also of concern is that the problems are beginning to appear at increasingly younger ages.

The number of new cases of cancer has also increased in recent years.

In particular, prostate cancer (in men), breast cancer (in women), colorectal cancer, and lung cancer are the most frequently diagnosed cancers.

Interestingly, the incidence of lung cancer in women has increased by about 50% in a decade.

And skin cancer has increased even more in both men and women, about 250% over two decades.

The thing is that these cancers are largely preventable with some simple lifestyle changes:

Lifestyle modifications are a hugely valuable prevention tool

In cardiovascular disease, the approach of lifestyle modifications together with proper follow-up and new medical technology has resulted in a significant decrease in deaths due to these conditions.

After a rapid rise after World War II, cardiovascular disease rates have declined by 10-20%.

This is due to proper prevention and treatment, including lifestyle modifications.

But when we look at all causes of death, regardless of age, chronic conditions still remain the biggest killer.

Particularly alarming is that mental health is also greatly affected, especially among young women. A lot of people struggle with anxiety disorders and depression, for example.

So the use of antidepressants is very high and continues to rise. In some cases, depression leads to suicide.

Going from infectious diseases to chronic diseases: Conclusion

Going from infectious diseases to chronic diseases is a direct result of improved medicine thanks to modern science.

However, our lifestyle has allowed chronic diseases to flourish.

Better food and healthier overall lifestyles are as vital for prevention as for cure.

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About Heather Campbell

As a nutritionist, my field of specialization is science-based nutritional advice but more importantly, it is my goal to share capturing and inspiring stories, examples and solutions which can help plus-size individuals overcome their specific difficulties. Read More