In mathematics, we simply say A larger than B larger than C. However, that is grammatically incorrect, because there is no verb in it.
In my case,
A: people who still smoke
B: people who used to smoke
C: people who never smoked
One way of specifying A > B > C is ...
A has a higher risk of cancer than B and B has a higher risk of cancer than C.
But considering B is too long and I wonder if there is any way that I can just mention B once.
A has a higher risk of cancer than B and in turn than C?