Can someone explain the link of the lowered life expectancy to flu and pneumonia? I thought that these were deceases that were only fatal for people with compromised immunity.
No, they are not. They are likely to be much more dangerous for those groups, but the flu or pneumonia can kill anyone.
Some strains of the flu are believed to be more deadly to the "strong" patients, due to a phenomena known as "cytokine storm" - where the strong immune system response directly contributes to death.
The 1918 flu strain was unusual in that it was more effective in killing previously healthy adults because it stimulated an immune system overreaction. So having a weakened immune system when exposed to this H1N1 strain actually increased survivability.
The 1918 flu was exceptional in that aspirin recently became a generic drug and the recommendation was to soak the patient in it. The symptoms of aspirin poisoning are similar to those of pneumonia (the main cause of death via flu).
>"In February 1919…Edward's fever kept getting higher and higher…aspirin…was given to him by the 1/2-handful over and over…Edward sweated through his mattress…Dr.…could not save his patient.
[...]
A confluence of events created a “perfect storm” for widespread salicylate toxicity. The loss of Bayer's patent on aspirin in February 1917 allowed many manufacturers into the lucrative aspirin market. Official recommendations for aspirin therapy at toxic doses were preceded by ignorance of the unusual nonlinear kinetics of salicylate (unknown until the 1960s), which predispose to accumulation and toxicity; tins and bottles that contained no warnings and few instructions; and fear of “Spanish” influenza, an illness that had been spreading like wildfire."
https://academic.oup.com/cid/article/49/9/1405/301441
Flu and especially pneumonia can be deadly to anyone just a lot less likely. Since the seasonal flu variate in intensity appended with off-season flu's added to the death rate from this kind of diseases. Just a hypotheses though, nothing concrete.
If you get the flu as a healthy adult, you're statistically likely to be fine, but you absolutely may die, especially with some of the nastier strains.
Wow, maybe (not being sarcastic) eating a monocultured food diet and living as sedate humans in sterile environments has a bigger effect on our immune systems than we'd like. This must have been measured? Compare immunity in farmers vs office workers or some such?
I'd have thought, if anything, that a farmer living in a rural environment saw less exposure to (human) diseases than an office worker in an urban environment. They have far less exposure to _people_, after all, and people are generally the main carriers.
Also, basically no-one works in a sterile environment. There's a reason that so many places have hand sanitiser dispensers.
I think you underestimate the amount of bad health environments there are in cities (anecdotal evidence only). I would not call most cities or working environments anywhere close to sterile.
To be honest, nobody is talking about very deadly exposure to pesticides in farmers populations. There actually have been papers published on that. While living outside a big city might be on average better for you, being a farmer is probably not.
Actually: lots of people bring a lot of diseases with them, so it you judge by germs, I would argue a city with buses, train stations, airports and harbors would be worse than any soil outside of it. Though it says nothing about food, can't argue there. Though (from experience) "farmers" tend not to be too broad in their nutritional uptake and eat mostly the same where I come from as people in the cities. Might be different in the states though.
Its immunity before you're exposed that at issue. How did you grow up? What routine exposures did you experience?
I grew up muddy and dirty, eating anything I found in nature that was mostly edible (apples, ground cherries, berries, chewing bark and grass), as well as organic beef and pork (before we knew what that meant) and garden vegetables. That was closer to historical experience.
Some strains of the flu are believed to be more deadly to the "strong" patients, due to a phenomena known as "cytokine storm" - where the strong immune system response directly contributes to death.