红字部分的区别？

以下两种骨折的区别？

Alendronate 70 mg once weekly and risedronate 35 mg once weekly are the most commonly used bisphosphonates worldwide. In the Fracture Intervention (FIT) study, alendronate was shown to reduce the incidence of vertebral, wrist and hip fractures by approximately half in women with prevalent vertebral fractures [207–209]. In women without prevalent vertebral fractures, there was no significant decrease in clinical fractures in the overall population, but the reduction was significant in the one third of patients that had a baseline hip BMD T-score lower than − 2.5 SD [210]. In a population of more than 90,000 men and women aged 80 years and older and who had sustained a prior fracture, a case-control analysis revealed that alendronate use was associated with a 34% decrease in hip fracture risk, and a 12% lower mortality risk but with a 58% increase in the risk of mild upper gastrointestinal symptoms [211].

prior fracture 和prevalent vertebral fractures的区别？