Ok so official cause of death is the most important aspect on a death certificate. The causes of death are listed numerically. So, number 1 is the official cause of death, but number 1 can be 1a, 1b, 1c etc. So it would read 1a ..... is caused by 1b ..... which is caused by 1c. 1c is the OFFICIAL cause of death, the overriding factor of everything else. There can also be numbers 2, 3 etc and these can be contributory factors but nothing to do with official cause of death legally. So a person may have 1. Heart attack 2. (Something else) but the heart attack would be the ultimate overall cause of death. That is unfortunately, what doctors etc listen to when looking at if someone can die from something. In the U.K., only Merryn and Sophia have this.
I hope this is clear and clears up a few things. This is why for example, the deaths relating to suicide will never have ME as official cause of death because the suicide is what killed the person. Those figures should be used in their own right though, as they are devastating and reflect how little support pwME receive