This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Osteology, Subject name: Pathology
A 24-year-old man on chronic corticosteroid therapy for severe asthma presents with a 6-month history of increasing hip pain. This patient most likely exhibits symptoms of which of the following metabolic bone diseases? 
Select and explain. 
A. Gaucher disease, B. Osteomalacia, C. Osteopetrosis, D. Osteoporosis
D: Osteoporosis
Answer: D: Osteoporosis 
Explanation: Risk factors for osteoporosis include smoking, vitamin D deficiency, low body mass index, hypogonadism, a sedentary lifestyle, and glucocorticoid therapy (seen in this patient). Bone loss and fractures are the hallmarks of osteoporosis, regardless of the underlying cause. Choices A and C are congenital disorders that are not related to corticosteroid therapy. Choices B and E are acquired conditions but they are not related to corticosteroid therapy.Diagnosis: Osteoporosis