This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Which of the following conditions are associated with osteoporosis? 
Select and explain. 
A. Cushing's syndrome, B. Anorexia nervosa, C. Acromegaly, D. All the above
D: All the above
Answer: D: All the above 
Explanation: Cushing's syndrome, anorexia nervosa and acromegaly are all associated with osteoporosis. Other endocrine disorders associated with osteoprosis are hyperparathyroidism, thyrotoxicosis, type 1 diabetes and adrenal insufficiency.