Osteoporosis is frequently categorized as primary or secondary osteoporosis. Primary osteoporosis is associated with menopause, advancing age, and “idiopathic osteoporosis” that may be seen in premenopausal women and middle-aged men. Secondary osteoporosis is caused by certain medical conditions or treatments that prevent either attainment of peak bone mass or enhance bone loss. Diseases commonly associated with increased risk of developing generalized osteoporosis in adults include (1) hypogonadal states, (2) endocrine disorders such as Cushing’s syndrome, hyperparathyroidism, thyrotoxicosis, insulin-dependent diabetes mellitus, acromegaly, and adrenal insufficiency, (3) nutritional and gastrointestinal disorders, (4) rheumatologic disorders including rheumatoid arthritis and ankylosing spondylitis, (5) hematologic disorders and malignancy such as multiple myeloma, lymphoma, leukemia, and malignancy-associated parathyroid hormone-related (PTHrP) production, (6) several inherited disorders, and (7) other disorders such as immobilization, chronic obstructive pulmonary disease, pregnancy and lactation, scoliosis, multiple sclerosis, sarcoidosis, and amyloidosis.