Modern healthcare is very bad at treating chronic illnesses. Symtomatic treatment is not a cure. I believe if people would live by these simple rules chronic diseases would be actually prevented and cured (in order of importance and effectiveness):

1. Don't mouthbreathe and don't overbreathe. See "Breath - The New Science of A Lost Art" by James Nestor for why and how.

2. Don't eat sugar, it's a chronic poison. See https://www.youtube.com/watch?v=dBnniua6-oM

3. Min. 1 hr of physical activity per day. Your body is not meant to sit all the time.

4. Avoid noise of the city life as much as you can. It leads to chronic stress and thus chronic diseases. Noise-cancelling earphones may help.