Fracture threshold in the Thai elderly and bone mineral density evaluation.

Fractures in the elderly as the result of minor trauma or normal physiological stress in daily activities usually occur in load-bearing body areas such as the lumbar spine and the neck or trochanter of the femur, causing high morbidity and mortality. Surveillance of high-risk Thai elderly with low bone mineral density by determining the cutoff point as the fracture threshold may guide us in the proper management for preventing these unpleasant events. Of 329 elderly with age range of 50-110 years, 63 with lumbar spine fracture and 55 with hip fracture were descriptively and studied prospectively during May 1997 to December 1998 at Pramongkutklao Hospital. Bone mineral density (BMD) was analyzed to determine the fracture threshold using a receiver-operating characteristic (ROC) curve and compared with the total BMD at the lumbar spine and proximal femur. The cutoff point of the lumbar BMD at 0.799 g/cm2 (78.30% sensitivity, 73.60% specificity, and 74.5% accuracy) yields the likelihood of lumbar spine or hip fracture. For the femoral BMD, the cutoff point at 0.649 g/cm2 (92.5% sensitivity, 73.2% specificity, and 73.05% accuracy) is also used to predict the likelihood of lumbar spine or hip fracture. Of the nonfracture group, 27.33% had a total BMD value below the fracture threshold. In conclusion, early prevention among the elderly to decrease the risks of fracture is very important. Also, the detection and fracture prevention for normal population who had BMD below the fracture threshold are interesting. The BMD measurements and the loss of bone mass in Thai elderly people and the other risks of fracture need further studies.