This is from the UK ONS, Em, for 2011.
"Figures released today show that mortality rates last year were the lowest ever recorded for England and Wales, at 6,236 deaths per million population for males and 4,458 deaths per million population for females.
Cancer accounted for 30% of them, with circulatory diseases, such as heart disease and strokes, the cause of 29%.
But cancer death rates have fallen by 14% for men and 10% for women in the previous decade.
And between 2001 and 2011, the death rates for circulatory diseases fell by 44% to 1,803 deaths per million population for males and 1,110 deaths per million population for females"
So death from all types of cancer is a close candidate for highest contributor to the mortality rate, hotly contested by cardiovascular problems.
Lung cancer would not be the highest single contributor to mortality, although it might the single largest contributor to death by cancer - an important distinction given the topic of conversation.
Smoking, of course, contributes a lot to the overall mortality rate, impacting as it does on cardiovascular, respiratory and cancer related deaths....
As far as this particular case goes - it would be preferable if prospective donors were non alcoholic non- smokers - but we do not, at this moment in time, have that luxury. There are far more recipients, some in a desperate state of health, than there are donors.