This would be useful information to have, but I don't agree that this makes the data meaningless. No matter when you are killed, and what by, your life has been cut short. Just because certain diseases (e.g. heart disease) mostly kill older people doesn't mean they aren't most important and worth tackling. If in the future due to medical advancement most people are living to 100+, we will regard dying at 80 an early death and a travesty.