In reply to LeeWood:
You are right that advances in hygiene and sanitation have probably done more than anything else to increase overall life expectancy. However, even with perfect hygiene and sanitation, a huge number of people would still die or lose important functions from conditions which are now simply treated by surgery - and this has been been made possible (or at least humane) by the development of anaesthesia, which depended entirely on advances in drug research.
And even with good hygiene and sanitation, plenty of clean-living folk still get pneumonia and other infections which can be life-threatening without antibiotics.
Post edited at 23:02