Calcif Tissue Int (1995) 56:186-191 SLIP aJ 9 1995 Springer-Verlag New York Inc. Bone Density in White Brazilian Women: Rapid Loss at the Time Around the Menopause V. L. Szejnfeld, 1 E. Atra, 1 E. C. Baracat, 1 J. M. Aldrighi, 2 R. Civitelli 3 IDivision of Rheumatology, Escola Paulista de Medicina, Rua Botucatu, 140, Silo Panlo, SP, Brazil 2Division of Gynecology, Departments of Medicine and Obstetrics and Gynecology, Escola Paulista de Medicina, Silo Paulo, Brazil 3Division of Bone and Mineral Diseases, Washington University School of Medicine at the Jewish Hospital, 216 S. Kingshighway Blvd., St. Louis, Missouri, 63110 USA Received: 29 April 1994 / Accepted: 4 October 1994 Abstract. Dual energy x-ray absorptiometry (DXA) was used to measure bone mineral density (BMD) of the lumbar spine and proximal femur (neck, Ward's triangle, and tro- chanter) in 417 normal women (aged 20-79) living in S~o Paulo, Brazil. Bone density decreased with age at all sites. At the spine, the greatest decrease occurred during the sixth decade, with an average 11.4% bone loss compared with the previous decade. Stratifying the subjects according to meno- pausal status revealed that the fastest bone loss occurred at the time around the menopause (ages 45-60) when the rate of bone loss (-0.66%/year) was almost twice as rapid as in postmenopausal women (-0.39%/year). Although signifi- cant linear rates of bone loss were detected in all proximal femur sites before the menopause, a menopause-dependent pattern was less evident than at the spine. Lifetime rates of bone loss at the appendicular skeleton were -0.43, -0.62, and -0.35%/year at the femoral neck, Ward's triangle, and trochanteric area, respectively. After the menopause, BMD declined with menopausal age at all sites, although the rate of bone loss was faster at the femoral neck (-0.62%/year) and Ward's triangle (-0.84%/year) than at the spine (-0.49%/year). The results are consistent with the notion that in women, the fastest bone loss occurs at the time around the menopause, most likely consequent to ovarian failure; and that faster rates of bone loss are detected at the proximal femur than at the lumbar spine in late postmeno- pausal women. Key words: Bone mineral density -- Dual energy X-ray ab- sorptiometry -- Osteoporosis -- Menopause. than other ethnic groups [7, 10]. In addition to the genetic potential, environmental factors also play a significant role in determining bone density in single individuals and in peo- ple living in specific geographical areas. For example, sib- lings of Japanese immigrants born in the United States were found to have higher bone densities than Japan-born immi- grants [11]. Therefore, the diagnostic value of bone mass measurements in a determined population living in a certain geographical location is heavily dependent on the knowledge of historical data obtained in healthy subjects living under the same environmental conditions and with similar ethnic characteristics. Deviations from normative values can thus be used to assess the risk of fractures, and to establish the need of therapeutic interventions. Although bone density of white populations of diverse ethnic origin can be reasonably compared [12, 13], data on age-related distributions of bone density in predominantly Latin-American populations are still scanty. Normative data for Argentinean women have been reported [14], and only one study has compared bone mineral density (BMD) of the spine and proximal femur between healthy young women and postmenopausal osteoporotic patients in subjects living in Brazil [15]. However, that study did not provide numeri- cal data that could be used as normative reference values of bone density according to age groups in Brazilian female populations. This study was aimed at establishing normal reference values for vertebral and proximal femur bone density, and at defining patterns of age-related bone loss in Caucasian women living in an area of southern Brazil using dual energy x-ray absorptiometry (DXA). Bone mass is the most important factor for the skeleton to support the load of the body, and to withstand the stress of everyday life [1, 2]. Although bone density can be measured with good precision, the wide interracial variability in bone mass precludes the use of single normative data. People of African origin have higher bone density [3-6] and fewer os- teoporotic fractures [7, 8] than age- and weight-matched whites. Furthermore, blacks attain a higher peak bone mass compared with Caucasians, probably because of a greater bone density growth at puberty [91. Likewise, people of Asian origin are thought to be at increased risk for fractures Correspondence to: V. L. Szejnfeld Materials and Methods Experimental Subjects Normal Brazilian women, all residents of Sgo Paulo city (southwest- ern Brazil), served as subjects for this study. The sample was com- prised of Caucasian females, all born in Brazil, in good health from 20 to 79 years of age. Most of the subjects were recruited from three different outpatient clinics in the area. These subjects were healthy women undergoing routine gynecological examinations and/or phys- ical examinations. The youngest subjects (20-29 years) were volun- teers recruited among medical students attending the Escola Paulista de Medicina. Each subject underwent a medical interview to verify inclusion/exclusion criteria before undergoing a complete physical examination and bone density measurement.