The combination of body mass index and age as a new index for identifying osteoporosis in Thai postmenopausal women.

Objective: The purpose of this study was to evaluate the application of the combination of bone mass index (BMI) and age as a new screening tool to identify osteoporosis in Thai postmenopausal women.

Design: Diagnostic study.

Material And Method: Bone mineral density (BMD) data of Thai postmenopausal women, age 40-80 years old who attended the outpatient clinic, Thammasat University Hospital, Thailand, between January 2004 and December 2008 were enrolled. The participants with history of metabolic bone disease or use of drugs associated with secondary osteoporosis and/or history of treatment for osteoporosis were excluded. Each had BMD records of lumbar spine, femoral neck and intertrochanter. The data were completely collected in all 372 women. A diagnosis of osteoporosis made according to WHO criteria.

Results: The prevalence of osteoporosis at lumbar spine, femoral neck and intertrochanter were 8.1%, 20.2% and 15.3% respectively. The combination of BMI and age as the index to detect osteoporosis had a sensitivity at 76.67%, 76% and 77.19%, respectively. The OSTA index at the standard cut-point of -1 had a sensitivity at 80%, 70.67% and 70.17%, respectively. Raising the cut-point to < or =0 would had a sensitivity at 90%, 85.33% and 78.95%, respectively.

Conclusion: The application of the combination of BMI and age as a screening tool is another option to identify osteoporosis in Thai postmenopausal women. Change the cut-point of < or =0, OSTA index could improve the detection of osteoporosis at a very high level of the sensitivity.