Roman says that the risk of osteoporosis can be reduced by making a certain lifestyle choices. which lifestyle choice could roman be referring to

Certain lifestyle changes like increasing the intake of Vitamin D and calcium could lower the risk of osteoporosis.

Explanation:

On the basis of what Roman narrates regarding the threat of osteoporosis, a certain lifestyle choice that would minimize the threat of the condition would be increasing the consumption of calcium and calcium-rich components, and enhancing the uptake of Vitamin D for the absorption of calcium.  

In order to cure the conditions like osteoporosis, the consumption of calcium is possibly one of the prime things that one should do.