In a patient on chronic glucocorticoids, osteoporosis primarily results from which cellular process?

• A. Stimulating osteoblast activity and reducing bone resorption
• B. Inhibition of osteoblast activity and increased bone resorption
• C. Decreasing osteoclast formation
• D. Enhancing calcium absorption in the gut

Answer: (B)

Chronic glucocorticoid use causes osteoporosis primarily by suppressing bone formation and increasing bone resorption. Glucocorticoids inhibit osteoblast differentiation and promote osteoblast and osteocyte apoptosis, leading to a marked drop in bone formation. At the same time, they enhance osteoclast activity, partly by altering the RANKL/osteoprotegerin balance to favor osteoclast development and function, so bone resorption rises. The combination produces a net loss of bone mass and weakened bone structure. Additional effects, like reduced calcium absorption from the gut and increased renal calcium loss, can worsen bone loss, but the central mechanism described is the dual hit of decreased osteoblast activity and increased osteoclast-mediated resorption.