For life expectancy you could use either low or short, since they are referring to the number amount (someone’s age in years). You would not say that life is low, it would sound like you were giving life a position or a height. Life is short would be correct because it is referring to the duration of time. Hope this helps!

I saw the phrase “low life expectancy” in an article. Both “short” and “low” work. You can think of life expectancy as a number (low) or a time (short). It could depend on the context.