Material and Method: The present study was conducted in 4,528 women of > 40 years who underwent first BMD measurement at King Chulalongkorn Memorial Hospital between 2000 and 2010. Bone mineral density (BMD) of femoral neck (nondominant side) and lumbar spine (L1-L4) was measure by Dual-energy x-ray Absorptiometer (DXA). The percentage of osteoporosis was determined by WHO cutoff value using Thai nationwide reference database.

Results: The percentages of osteoporosis at femoral neck (FN) in age group of 40 to 49, 50 to 59, 60 to 69, and > 70 years were 6.2%, 7.4%, 24.4%, and 51.8% respectively. The corresponding figures for lumbar spine (LS) were 3.4%, 5.6%, 12.7%, and 20.9% respectively. The percentage of osteoporosis seems to increase strikingly after 60 years at both sites. The percentage of osteoporosis at FN in underweight, normal weight, overweight and obesity were 52.1%, 20.3%, 15.7%, and 9.4% respectively. The corresponding figures for LS were 22.8%, 12%, 4.8%, and 5.9% respectively. Over 30% of women of age > 60 years with BMI of less than 23 kg/m2 had osteoporosis by the studied criteria.

Conclusion: The percentage of osteoporosis seemed to be increasing with age and declining with BMI. Using the WHO cutoff value and Thai reference database, the percentage of femoral neck osteoporosis appeared to be higher than the lumbar spine. In the present study, the authors found that women of > 60 years with BMI of less than 23 kg/m2 posed a substantial percentage of osteoporosis.

Keywords: Osteoporosis, Bone mineral density (BMD), Body mass index (BMI)