SPINE FRACTURE RISK IS PREDICTED BY NON-SPINE FRACTURES

A prospective cohort study of 1098 postmenopausal Japanese-American wo men evaluated the relationship between baseline non-spine fractures an d new (incident) spine fractures. At the baseline examination in 1981, prevalent non-spine fractures were ascertained by interview, and prev alent spine fractures by radiograph. Bone mass measurements of the dis tal radius, proximal radius, calcaneus (1981), the lumbar spine (1984) were obtained and repeated at 1- to 2-year intervals. Women with exis ting non-spine fractures have a threefold greater risk of subsequent s pine fractures, independent of bone mass, and independent of the known association between prevalent spine fractures and subsequent spine fr actures. Women with both a prevalent non-spine fracture and low bone m ass (50th percentile or lower) have an eightfold greater risk of new s pine fractures compared with women above the 50th percentile of bone m ass and no prevalent fractures. In addition to low bone mass, both pre valent spine fractures and prevalent non-spine fractures are strong ri sk factors for subsequent spine fracture. These data suggest that not all osteoporotic risk factors are expressed via bone mass, and that ot her, unmeasured risk factors, such as bone quality defects, may explai n these results. In clinical terms, women with both prevalent fracture s and low bone mass should be recognized as being at extremely high ri sk, and treatment potency should be commensurate with this level of ri sk.