Easily the 53K.
The 5 million that died almost always made the choice to smoke at some point. That doesn't mean they "deserve" it or anything like that, but it was an act of their own free will that led to their death. For all it matters, perhaps they loved smoking and it was their one joy in life, something they would never give up. Maybe it was positive to them. That's not for me to decide and they should be free to do that. Maybe they got addicted and don't feel they have a choice anymore, but they still did have that choice at one point even if they're unhappy with where they are now. Just because it led to their eventual death doesn't automatically mean they're suffering addicts that cry themselves to sleep every night. They could very well be enjoying their freedom to have a good time.
The 53K suffer from something that is largely not their choice. As such, it cannot have been prevented by them.