This is Why We Die

Most of us die from ageing. For every person that dies in a car accident, 34 have died from cancer, cardiovascular disease, diabetes, and other age-related diseases. Compared to homicide (105 to 1) and conflict (357 to 1) it’s even more striking[1].

Yet we don’t focus most of our energy on preventing age-related diseases. And maybe with good reason, one day we will die (probably). But what if we could extend our healthy lifespan by 10, 20, 50 or even more years. I for one think that is a very exciting possibility.

Today is the right time to start thinking about this, or as the Chinese would say: “The best time to plant a tree was 20 years ago, the second best time is now.” To the best of my knowledge, we are now at the point where we start to understand some of the underlying processes that cause ageing.

The elixer of life is now growing on the tree of knowledge and this is my first step at learning more about this.

Why We Die

With all that being said, here are the 7 reasons/categories why we die. I’ve taken these from Aubrey de Grey (wiki), a brilliant gerontologist/connector/promoter of the fight against ageing. Here we go:

  1. Mutations – in chromosomes
    • this causes cancer due to changes in the nuclear DNA, proteins that bind to this, or molecules that contain genetic information in the eukaryotes
  2. Mutations – in mitochondria
    • this causes problems in the energy-producing parts of a cell (the mitochondria), again these are changes to the (local) DNA
  3. Junk – inside of cells
    • when the junk inside the cell is not being cleaned/digested properly neurodegenerative diseases rear their heads
  4. Junk – outside of cells
    • the same but this time outside/in-between cells, Alzheimer’s senile plaques are the most well-known example of this
  5. Cells – too few
    • some cells don’t get replaced (or too slowly) and this makes us weaker with age (Parkinson’s disease, immune system)
  6. Cells – too many
    • the dead cells that don’t divide but also are in the way (senescence), they can block space for living cells or even secrete proteins that do harm
  7. Extracellular protein crosslinks
    • cells are held together by linking proteins and when too many connections form, they lose elasticity

Which Diseases are Responsible?

If we look at it from another angle, the diseases that kill us, what is it that actually takes us out? All of them have links to the 7 systems described above, yet all in different ways, which I hope to describe in future in-depth blogs.

  1. Cardiovascular diseases (18 million, 32%)
    • A class of diseases that involve the heart or blood vessels
    • “The most important determinant of cardiovascular health is a person’s age.”[2]
    • Related terms: caloric restriction (CR), sirtuins, IGF-1, rapamycin (mTOR)
  2. Cancers (9 million, 17%)
    • A disease caused by an uncontrolled division of abnormal cells in a part of the body
    • “Ageing is the inevitable time-dependent decline in physiological organ function and is a major risk factor for cancer development. “[3]
    • Related terms: genomic instability, telomere attrition, epigenetic changes, loss of proteostasis, decreased nutrient sensing and altered metabolism, cellular senescence and stem cell function
  3. Respiratory disease (3.5 million, 7%)
    • A type of disease that affects the lungs and other parts of the respiratory system. Includes asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, pneumonia, and lung cancer [4]
    • “The respiratory system undergoes various anatomical, physiological and immunological changes with age. The structural changes include chest wall and thoracic spine deformities which impairs the total respiratory system compliance leading to increase work of breathing .”[5]
    • Related terms: Stiffening of the thoracic cage (7th underlying principle), lower respiratory muscle strength (especially in men),
  4. Diabetes, blood and endocrine disease (3 million, 6%)
    • A disease in which the body’s ability to produce or respond to the hormone insulin is impaired, resulting in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood
    • “Almost one-third of U.S. adults over the age of 65 years have diabetes. Approximately half of those are undiagnosed, and an additional one-third of older adults have prediabetes.”[6]
    • Related terms: impaired glucose intolerance, postprandial hyperglycemia, defects in β-cell function, metformin
  5. Lower respiratory infections (2.5 million, 4,5%)
    • Lower respiratory tract infections are any infections in the lungs or below the voice box. These include pneumonia, bronchitis, and tuberculosis
    • Viruses, bacteria, fungal infections, and mycoplasma are the main causes.
    • I guess this one is a bit of an odd one out, it’s not so much related to ageing as to health (in how strong your body is to overcome this). Also, the main burden of it is felt in subsahara Africa. [7]
  6. Dementia (2.5 million, 4,5%)
    • Dementia is a general term for a decline in mental ability severe enough to interfere with daily life. Memory loss is an example. Alzheimer’s is the most common type of dementia
    • “Epidemiological studies have shown that dementia could be avoided even at extreme old ages.” The incidence of dementia has also gone down in the last few decades. [8,9]
    • Related terms: Amyloid-beta, microglia (CD22), P. gingivalis
  7. Neonatal deaths (1.7 million, 3%)
    • The first cause on the list that is not directly related to ageing
    • Neonatal deaths are all the children that die in the first month
    • This has fallen dramatically from 140/1000 (14%) to 5/1000 (0,5%) of births [10]
  8. Diarrheal diseases (1.7 million, 3%)
    • The second cause on the list that is not directly related to ageing
    • Diarrheal diseases are a collection of diseases caused by multiple viral, bacterial, and parasitic organisms that share the common symptom of diarrhoea, defined as the passage of three or more loose or liquid stools per day
    • Especially kids and the elderly are the most at risk (thus in a way linking it to ageing, at least for the latter group)
  9. Road incidents (1.3 million, 2%)
    • Not related to ageing, and unfortunately something that hasn’t gone down over the last 10 years
    • It has gone down in some countries (e.g. Germany) where safety measures prevent deaths
    • The most vulnerable group is in the 70+ bracket (35/100.000 people)
  10. Liver disease (1.3 million, 2%)
    • Not strictly related to ageing, but damage over time may lead to liver cancer

Together this top 10 causes of death cover approximately 85% of deaths. If we remove all those not strictly related to ageing, we still have 73% of deaths that are related to ageing directly.

Other Causes?

I think this list doesn’t cover everything we think of when we image death. Two things are missing that many relate to deaths. The first is war/conflict/terrorism [11]. The second is our lifestyle.

War used to be a much more common cause of death. Until the 20th century, most countries were at war, not at peace. The peak in the last 100 years was the second world war, with 22 deaths per 100.000. Today it stands at just over 1 per 100.000.

Our lifestyle is not something to boast about. Obesity stands at 13% worldwide, and at 28% in North America and Europe [12]. And I think that this can be one of the causes/co-factors of many of the causes of death listed above. Together with air pollution, bad diets, no exercise and other lifestyle related choices, we should count ourselves lucky that we’re actually living this long.

In this post I’ve explored the causes of death and looked at the diseases that eventually tackle us. I’m optimistic that we will find solutions to most, if not all, of these in the coming decades. Our solutions should be combined with an approach in which we also make sure we do our best to keep our body healthy through diet and exercise.

To end a short analogy. Imagine yourself as a car. If you run it down, put in the wrong fuel, and eventually drive it total loss in a car accident, you would be a very irresponsible driver. If you take good care of your car, change the oil when needed, and sometimes push the peddle to the floor for just a sprint, then you might have a longer journey ahead. If then someone comes along and replaces a part of the car, or gives it a special fuel that restores the engine, you might be driving the car for a very long time to come.