This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'All are causes of Osteoporosis, except- \nSelect and explain. \nA. Thyrotoxicosis, B. Hypothyroidism, C. Chronic heparin therapy, D. Old age', 'role': 'user'}, {'content': "Answer: B \nExplanation: Causes of osteoporosis are : * Lifestyle factors * Risk increases with age * Genetic factors * Hypogonadal states * Endocrine disorders - premature ovarian failure, adrenal insufficiency, Cushing's syndrome, central adiposity, Diabetes mellitus (types 1 and 2), hyperparathyroidism, thyrotoxicosis. * Gastrointestinal disorders * Hematologic disorders * Rheumatologic and autoimmune diseases * Central nervous system disorders * Miscellaneous conditions and diseases like AIDS/HIV, alcoholism, amyloidosis * Medications - aluminum (in antacids), Anticoagulants (heparin), Anticonvulsants, Aromatase inhibitors, Barbiturates, Glucocoicoids , GnRH antagonists and agonists, Cancer chemotherapeutic drugs, Lithium, Cyclosporine A and tacrolimus, Depomedroxyprogesterone (premenopausal contraception), Proton pump inhibitors, SSRIs, Tamoxifen (premenopausal use), Thiazolidinediones, Thyroid hormones (in excess), Parenteral nutrition. Reference : page 2490 Harrison's Principles of Internal Medicine 19th edition", 'role': 'assistant'}]