If Osteoporosis is a hereditary risk factor in your family, I hope you are supplementing with a Calcium Citrate supplement like Citrical or one of the generics. Use the Citrate because you can metabolize the calcium easier than a Calcium Carbonate supplement, by the way, and make sure it has a Vitamin D supplement in it as well, as that will help with the Ca uptake as well. Talk to your Dr or a Dietitian for proper dosing amounts, though.
Do some load bearing exercises as well, by the way, like freeweights and body mass utilizers like squats, etc. Load bearing exercise will encourage greater bone density as part of the metabolic process. It also builds stronger muscles, so you have a +/+ situation there.
A Bone Density test would also be a recommendation I'd make, since a routine of exclusively cycling can lead to Osteopenia in the lower spine, which is a pre Osteoporosis condition.
The bones you save will be your own.