644 J Med Assoc Thai Vol. 95 No. 5 2012 Correspondence to: Rithirangsriroj K, Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand. Phone: 0-2256-4241 E-mail: choyu56@hotmail.com Osteoporosis in Different Age-Groups and Various Body Mass Index (BMI) Ranges in Women Undergoing Bone Mass Measurement at King Chulalongkorn Memorial Hospital Kunthida Rithirangsriroj MD*, Krasean Panyakhamlerd MD*, Sukanya Chaikittisilpa MD*, Tawatchai Chaiwatanarat MD**, Nimit Taechakraichana MD* * Department of Obstetrics and Gynecology, King Chulalongkorn Memorial Hospital, Bangkok, Thailand ** Division of Nuclear Medicine, Department of Radiology, King Chulalongkorn Memorial Hospital, Bangkok, Thailand Objective: To determine percentage of osteoporosis at femoral neck and lumbar spine (L1-L4) in women with different age group and various BMI ranges. 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 (non- dominant 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/m 2 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/m 2 posed a substantial percentage of osteoporosis. Keywords: Osteoporosis, Bone mineral density (BMD), Body mass index (BMI) Osteoporosis is a worldwide health issue with increasing disease prevalence not only in the north-western countries but also in Asia and Latin America. Of various possible sites of fragility fractures, vertebral and hip fractures are associated with pronounced morbidity and excess mortality. Avoidance of debilitating fracture consequences is best achieved by identifying patients at risk and providing appropriate therapeutic intervention. For instance, low body weight and body mass index (BMI) were shown to be predictive of osteoporosis and associated with an increased fracture risk (1) . Osteoporosis is considered as the disease of the young but manifests in aging. In the United States, one third of women between 60 and 70 years have osteoporosis. Women at 75 years of age or over have an osteoporotic fracture rate as high as 80 to 90% (2) . In Thailand, the proportion of the aging population (over 60) was 7.2% in 1990 and is expected to increase to 15.2% in 2020 (3,4) . The prevalence of osteoporosis in Thailand was between 13 and 19% according to a nationwide survey during 1998/1999 (5) . With increasing life expectancy, osteoporosis is likely to be one of the major health problems in the upcoming decade. J Med Assoc Thai 2012; 95 (5): 644-9 Full text. e-Journal: http://www.jmat.mat.or.th