How do osteopenia and osteoporosis differ based on their word parts?

Osteopenia and osteoporosis differ in their word parts primarily through the prefixes used. 'Osteopenia' includes 'penia,' which means deficiency, indicating a lower than normal bone density. In contrast, 'osteoporosis' uses 'porosis,' meaning porous, which refers to a condition where bones become more porous and fragile due to significant loss of bone density.