The queen's death certificate says she died of 'old age'. But what does that really mean?

Queen Elizabeth’s newly released death certificate contains just two curious words under her cause of death – old age.

We might talk about people dying of old age in everyday speech. But who actually dies of old age, medically speaking, in the 21st century?

Such a vague cause of death not only raises questions about how someone died, it can also be hard on family and loved ones left behind.