Question

Which health factor is outside your individual control?

Answer 1

Clean living environment. Only fortune and opportunities can determine that, while you yourself can control the other two.

Answer 2

Having a support structure of people you can count on for advice. You can choose who your friends are, and you can try your best to have good friends you can count on, but this is two sided. You all haft to do your part to make this one work, so it is not individual.

But my second guess would be the clean living environment. This one, although it CAN be, is not always in your control.