11. Has severe osteoporosis or has had a bone fracture within a year prior to enrollment. For adults, severe osteoporosis as defined by the World Health Organization (WHO) as bone mineral density (BMD) 2.5 standard deviations below that of a young, normal adult (T-score at or below -2.5 and one or more fractures). For individuals, less than age 18, severe osteoporosis as defined by the First Pediatric Consensus Development Conference as a Z-score below -2 and one or more fractures.