Fractures associated with low BMD are deemed osteoporotic; however, it is unclear whether the degree of trauma should also be considered.OBJECTIVE
To evaluate the relationship between low BMD, high-trauma fracture and future fracture risk.DESIGN AND INTERVENTION
This study assessed community-dwelling adults aged ≥65 years, residing in seven geographically diverse US regions, who had enrolled in one of two prospective cohort studies. The Study of Osteoporotic Fracture (SOF) enrolled only white women, whereas the Osteoporotic Fractures in Men Study (MrOS) enrolled predominantly white men (89%). Exclusion criteria for both studies included bilateral hip replacement and requirement for ambulatory assistance from another individual. BMD at the proximal femur and lumbar spine was assessed at baseline in MrOS and during the second study visit in SOF. Other measurements included height, weight, BMI, history of falling within the past year, and history of fractures since age 50 years. Participants were contacted every 4 months to determine whether a fracture had occurred. Low-trauma fracture was defined as any fracture that resulted from a fall of standing height or less, or any mild or moderate trauma not resulting from a fall. High-trauma fracture was defined as any fracture that resulted from a fall of greater than standing height or from a motor vehicle accident.OUTCOME MEASURES
The main outcome measures were hip and vertebral BMD, nonvertebral fracture, and degree of trauma.RESULTS
SOF followed 8,022 women for a mean of 9.1 years and MrOS followed 5,995 men for a mean of 5.1 years. An initial high-trauma fracture was sustained by 264 women and 94 men, whereas an initial low-trauma fracture was sustained by 3,211 women and 346 men. Individuals who sustained a fracture were more likely to have low BMD (≤−2.5 SD) than those who did not experience fracture, regardless of sex or degree of trauma. For women, a 1 SD reduction in total hip BMD was associated with a 47% and a 50% increased risk of high-trauma and low-trauma fracture, respectively. Similarly, a 1 SD reduction in total hip BMD correlated with a 58% and a 67% increased risk of high-trauma and low-trauma fracture, respectively, for men. Age was associated with an increased risk of low-trauma fracture per 5-year increase in both men and women. Women with initial high-trauma or low-trauma fracture had a similar increased risk of subsequent fracture (34% and 31%, respectively). Subsequent fracture risk was not modeled for men; however, both high-trauma and low-trauma fracture groups had an increased incidence of new fractures (6.4% and 8.1%, respectively).CONCLUSION
High-trauma fracture was associated with low BMD and an increased risk of subsequent fracture, which suggests that affected individuals should receive the same osteoporosis care as those with low-trauma fracture.