Hadn't thought of these before

Life-saving inventions, people, and ideas: Cotton, shoes, fluoride, the Clean Air Act. - Slate Magazine

This post in Slate's longevity series lists "14 oddball reasons you're not dead yet".  Most of them I had heard of before, but I found two which were a bit new to me:

Cotton. One of the major killers of human history was typhus, a bacterial disease spread by lice. It defeated Napoleon’s army; if Tchaikovsky’s 1812 Overture were historically accurate, it would feature less cannon fire and more munching arthropods. Wool was the clothing material of choice before cotton displaced it. Cotton is easier to clean than wool and less hospitable to body lice.

And:

Pasteurization. This should be an obvious lifesaver, right up there with hand-washing and proper nutrition. But the rise of the raw milk movement suggests that a lot of people take safe dairy products for granted. Contaminated milk was one of the major killers of children, transmitting typhoid fever, scarlet fever, diphtheria, tuberculosis, and other diseases. One of the most successful public health campaigns of the late 19^th and early 20^th centuries was for pure and pasteurized milk—so successful that we don’t really remember how deadly milk can be.

 (I didn't realise that so many diseases had been associated with unpasteurised milk.)