History

The frustrating part about researching this is that dying of preventable malnutrition isn't regarded as dying because of the depression. Most literature I've seen on the topic is mortality rates actually dropped in the USA between 1929 and 1939 except regarding suicides. Life expectancy between 1920 and 1940 actually rose by 9 years among Americans.

Which to be fair, is probably because that's when everyone started getting vaccinated against tuberculosis. The vaccine was invented in 1921. It can't be overstated how many people died of TB, something like 80% of people in North America used to be infected with it, you had a 5 to 10% chance of developing active symptoms, and you had an 80% chance of dying if your TB went active. The vaccine basically eradicated tuberculosis from North America and now hardly anyone gets it. Used to be a top 5 cause of death.

That's part of why it's difficult to gauge these numbers. It's also difficult because the majority of people impacted by the great depression were poor and rural, and many of the victims were very young children. The USA didn't give much of a shit about formal census records of rural people until kinda recently. Birth certificates weren't issued until 1902, and weren't made federally standard until 1946. My great-grandmother born in 1896 didn't have a birth certificate and sometimes she'd brag about it.

I've also read an interesting theory about why life expectancy actually rises during big American recessions. Less work typically means less strenuous labor, fewer industrial accidents, less alcohol consumption and smoking, and more hours of sleep per night. Also means fewer cars on the road. America is such a stupid fucking country that economic recessions are actually good for public health?