I had to go to the emergency room last night for a minor issue. Everything is okay for me, but it made me think about death—how optimistic I am! 😂—and how to prevent it…

So here are the main causes of death in the developed world (it's quite different in low-income countries):

They can be grouped into the following categories:

• Cardiovascular: ischaemic heart disease, stroke, hypertensive heart disease

• Respiratory: chronic obstructive pulmonary disease (COPD), lower respiratory infections

• Cancers: trachea, bronchus and lung and colon and rectum

• Dementia (including Alzheimer’s disease)

• Kidney diseases

• Diabetes

Non-communicable diseases account for the majority of deaths in high-income countries. Homicides, terrorism, falls, drownings, fire, and natural disasters are negligible compared to these diseases, even though they’re the most talked about in the news.

However, suicide, drug overdose, road accident, and homicide are significant in the 15 to 49 years old category:

The only way to prevent some respiratory infections is to get vaccinated. For the other diseases, although there are genetic factors (like for most of our traits), there are also non-hereditary risk factors that we can control:

• Cardiovascular diseases: risk factors include high blood pressure (hypertension), smoking, diabetes, lack of exercise, obesity, high blood cholesterol, poor diet, depression, and excessive alcohol.

• COPD and lung cancer: the most common cause is tobacco smoking, with fewer cases due to air pollution.

• Colorectal cancer: risk factors include unhealthy diet (too much red meat and processed meat), obesity, smoking, lack of physical activity, and excessive alcohol.

• Dementia: risk factors for Alzheimer’s disease include less education, hypertension, hearing impairment (using hearing aids reduces the excess risk), smoking, obesity, depression, physical inactivity, diabetes, low social contact, excessive alcohol consumption, traumatic brain injury, and air pollution. Sleep disorder may be a risk factor as well. Some cognitive activities—such as book reading—are also associated with a lower risk of dementia.

• Kidney diseases: causes include long term usage of painkillers (such as aspirin), toxicity of chemotherapy agents, exposure to lead, diabetes, hypertension, and higher dietary intake of animal protein, animal fat, and cholesterol.

• Diabetes: risk factors include obesity and lack of exercise.

One risk factor can be associated with several diseases. So we can breakdown deaths by risk factor instead:

(Again, the ranking is different from 15 to 49 years old.)

Some risk factors—such as obesity or smoking—are easy to define and understand. Others are more subjective.

For instance, physical inactivity is defined as less than 150 minutes of moderating intensity activity per week (like brisk walking or cycling) or 75 minutes of vigorous-intensity activity (such as running or playing football). Being active can reduce the risk of developing some cardiovascular diseases by as much as 35%. And yet, 38% of adults in the UK do not meet this target.

Air pollution is mainly measured by the nitrogen dioxide (NO2) concentration and fine ambient particulate matter (PM)2·5. In big cities like London and Paris are still around the limit values: higher than the limit near roads and lower in the urban background. But the situation is improving, thanks to the modernization of cars.

It’s even harder to define a “healthy diet.” The most common recommendation in the literature is the Mediterranean diet: rich in olive oil, vegetables, fruits, unrefined cereals, and fish with low red meat consumption. Some people promote other diets, such as the ketogenic diet, based on recent studies. I’m extremely skeptical about studies in this field because you need a long timeframe (a lifetime?) to understand all the effects of a diet on the body. And it’s hard to know exactly what the people in the experiment ate and what was the quality of the food. So I prefer to follow Lindy’s law: I eat what has withstood the test of time. Peoples around the Mediterranean, including some of the greatest civilizations (Egyptian, Phoenician, Hellenistic, Roman, Ottoman…), have eaten the same way for centuries, if not millennia, I trust them. The cherry on the cake: it’s tasty! Anecdotally, if you plot life expectancy / GDP per capita, countries from the Mediterranean Basin often perform better than their richer non-Mediterranean neighbors: Spain has the same life expectancy as Switzerland but is twice as poor; Albanians and Lebanese live longer than Emiratis and Bahrainis, even though they are 4 to 7 times poorer. By the way, I wonder if the prohibition from eating pork (in Judaism and Islam) and beef (in Hinduism) may be a way to reduce the consumption of red meat.

Regarding alcohol, some studies show that moderating drinking (one to two drinks per day depending on gender) is associated with a decreased risk of heart disease, stroke, diabetes, and Alzheimer’s disease. [Edit: However, recent studies show this may not be true.] Here as well, academics are consistent with tradition. Indeed, red wine is part of the Mediterranean diet, and in 375 BC, Greek poet Eubulus was already writing:

Three bowls do I mix for the temperate: one to health, which they empty first, the second to love and pleasure, the third to sleep. When this bowl is drunk up, wise guests go home. The fourth bowl is ours no longer, but belongs to violence; the fifth to uproar, the sixth to drunken revel, the seventh to black eyes, the eighth is the policeman's, the ninth belongs to biliousness, and the tenth to madness and hurling the furniture. Too much wine, poured into one little vessel, easily knocks the legs from under the drinkers.

(One bowl was 250 mL with wine diluted at 1:2 or 1:3 with water. With today’s non-diluted wine, this means about 2 standard glasses of 175mL. [Edit: it’s unclear whether Eubulus was referring to the amount per meal or per day.])

[Edit: Many people think they drink moderately, but actually, in the US, two in three adult drinkers drink above moderate levels at least once a month. So if you can’t respect the guidelines, it’s better not to drink at all. It’s probably the reason why many religions forbid or discourage the consumption of alcoholic beverages. I rarely drink and won’t drink more, but from now on, when I drink, I’ll stick to red wine, and not more than one glass per meal!]

How much can you reduce your risk by modifying your behavior? For instance, it is estimated that “modifying 12 risk factors might prevent or delay up to 40% of dementias”. The remaining risks are either unknown or due to genetics. Same for other diseases.

So most of the ways to prevent the most common diseases are fairly simple and cheap. But could technology help as well?

The Apple Watch Series 6 and the Samsung Galaxy Watch 3 both have a sleep tracker, blood oxygen (SpO2) and heart rate monitoring, and an FDA-approved electrocardiogram (ECG) sensor. The Samsung Galaxy Watch 3 can also measure blood pressure, but you need to calibrate it first with a full blood pressure cuff. Therefore, these smartwatches can detect signs of atrial fibrillation, an irregular heartbeat that can cause blot clots and lead to stroke. In February 2020, Apple started a study with Johnson & Johnson to know whether the Apple Watch could prevent stroke or not.

Regular testing is also important to identify prediabetes and prevent progression to diabetes type 2. What if we all have devices at home to be regularly tested in the future? It would dramatically reduce the prevalence of diabetes.

All these technological developments are promising, but in the meantime, we only have one solution: exercise and eat healthily! :)

Antoine