Personally I've never seen a death certificate, have you? Have no idea, but both my parents died from cancer as that is what their doctors told me.
Seen many, completed many.
Yes I've seen them. We say people die from cancer. But that's the contributory cause. The primary or immediate cause of death would be let's say renal failure. The cancer attacks the organs so they stop working properly and you die. But we don't say the person died from renal failure, we say they died from cancer which caused the renal failure. I believe these often get confused or there may be unknown reasons especially if there's no autopsy. If someone is really old, and dies, they're not going to perform an autopsy unless it looks like there was foul play.
In the UK, there is considerable flexibility in certifying the cause of death. A death certificate contains
I(a) Disease or condition directly leading to death:
I(b) Other disease or condition, if any, leading to
I(a):
I(c) Other disease or condition, if any, leading to
I(b):
II Other significant conditions CONTRIBUTING TO THE DEATH but not related to the disease or condition causing it:
I've never certified a death in the US; the form may well be different.
The last sentence is untrue, at least in the UK: a death must be referred to the coroner if the deceased has not been seen by a doctor within two weeks of death. That rule has been relaxed for the last three months, which has done little to improve the reliability of data on cause of death.
Jeremy