A síndrome de Down (SD) é a causa genética mais comum de comprometimento intelectual associada a doenças sistêmicas, como o envelhecimento precoce e alterações músculo-esqueléticas que aumentam o risco de osteoporose (OP). A OP é uma doença do esqueleto, caracterizada por baixa massa óssea e deterioração da micro arquitetura do tecido ósseo, com aumento de fragilidade óssea e susceptibilidade à fratura, considerada um problema de saúde mundial, que aumenta o risco de mortalidade e os custos médicos. Tem como fatores de risco para o desenvolvimento de OP: sexo feminino, raça branca ou asiática, história familiar, imobilidade, abuso de álcool, massa muscular, uso crônico de corticosteróides, a falta de terapia de reposição hormonal, tabagismo, sedentarismo e baixa ingestão de cálcio. Muitos destes fatores podem ser encontrados em indivíduos com SD, onde recentemente a OP foi identificada em adultos jovens. O diagnóstico precoce da OP impede fraturas e é extremamente importante, realizado pelo exame absormetria de dupla energia de raios X (DXA), ou seja, a densitometria óssea, que determina a densidade óssea (DO). Embora exames radiográficos não serem precisos para o diagnóstico da OP, se bem interpretados, eles podem ser ferramentas poderosas para o screeening da OP. A radiografia panorâmica é o exame radiográfico mais solicitado do corpo humano e muitas vezes é realizado como exame complementar no diagnóstico odontológico. Assim, os dentistas podem desempenhar um papel importante para o diagnóstico da OP e prevenção de fraturas osteoporóticas. O objetivo deste trabalho foi comparar a radiografia panorâmica (PAN) com a DXA para identificar a OP na SD. Foram avaliados 37 pacientes com SD do CAPE/FOUSP, com idade mínima de 25 anos, cujos pais ou responsáveis concordaram e assinaram o Consentimento Informado (CEP-FOUSP 79/2009). Foram colhidos os dados do histórico médico, realizado a PAN e a DXA do rádio e da ulna. Na radiografia panorâmica foram avaliados a medida da largura da cortical mandibular e o formato da cortical mandibular usando o software Radiocef Studio 2. Foram comparado os resultados da PAN com os resultados da DXA. Os resultados mostraram 21 pacientes do sexo masculino e 16 do sexo feminino, sendo 33 pacientes brancos, 03 negros e 01 amarelo. A idade variou de 25 a 60 anos e 01 mês, com média de 32 anos. As medidas da cortical mandibular dos pacientes com SD variou de 1,94 mm a 4,49 mm, com média de 3,01mm. Na avaliação do formato da cortical mandibular, 2 pacientes apresentaram formato C1 (cortical mandibular normal), 15 pacientes apresentaram formato C2 (cortical mandibular com ligeira erosão) e 20 pacientes apresentaram formato C3 (cortical mandibular severamente erodida), segundo a classificação de Klemeti et al., 1994. O trabalho realizado nos permitiu concluir que os indicadores anatômicos mensuráveis de radiografias panorâmicas digitais normalmente utilizados para identificação de baixa DO na população normorreativa não devem ser utilizados como parâmetros para a identificação de baixa densidade óssea em pacientes com SD; o screening da OP em pacientes com SD deve ser baseado na avaliação clínica e nas mudanças radiográficas, uma vez que as alterações das estruturas ósseas destes pacientes dificultam a correlação com valores pré-estabelecidos e ainda que faz-se necessário a elaboração de valores padrões de indicadores anatômicos mensuráveis exclusivos para identificação de baixa densidade óssea em pacientes com SD. / Down Syndrome (DS) is the most common genetic cause of intellectual impairment associated with systemic disorders such as premature aging and muscle skeletal changes that increase the risk of osteoporosis (OP). The OP is an skeletal disease characterized by low bone mass and micro architectural deterioration of bone tissue, with increase of bone fragility and susceptibility to fracture, which is a global health problem, that increases the risk of mortality and medical costs. Risk factors for the development of OP are: female gender, white or asian race, family history, immobility, alcohol abuse, poor muscle mass, chronic corticosteroid use, lack of hormone replacement therapy, smoking, sedentary lifestyle and low calcium intake. Many of these factors can be found in individuals with DS, where recently the OP has been identified in young adults. Early diagnosis of OP prevents fractures and it is extremely important. It´s performed by the exam dual-energy X-ray absorptiometry (DXA), which determines the bone density (BD). However, these tests are not available for the Brazilian population in general. Although X-ray exams are not precise for the diagnosis of OP, they can provide powerful tools to screen potential patients with OP, since they are well interpreted. The panoramic radiograph (PAN) is the most requested x-ray of the human body and is often performed as a complementary test in dental diagnosis. Thus dental surgeons can play an important role for the diagnosis of OP and prevention of fractures. The aim of this study was compare PAN with dual-energy X-ray absorptiometry (DXA) to identify OP at DS. STUDY DESIGN: Patients with DS-CAPE/FOUSP, aged at least 25 years, who parents agreed and signed the Informed Consent (CEP-FOUSP 79/2009). The data from medical history was taken, it was performed PAN, and DXA of radius and ulna. The width and the shape of the mandibular cortical was evaluated at PAN using Radiocef Studio 2 software, and the results of PAN were compared with the result of DXA. CONCLUSIONS: The screening of OP in DS patients should be based on clinical evaluation and radiographic changes, since the changes of the bone structure of these patients are difficult to compare with values previously established.

O objetivo do trabalho foi avaliar o uso de minerais orgânicos na alimentação de potros, avaliando a deposição óssea de Cálcio e Fósforo, através de biopsia e densitometria óssea, além das medidas de crescimento, de altura da cernelha e da garupa, perímetro torácico, joelho, canela e ganho de peso. Foram utilizados dez potros com idade entre 10 e 13 meses e peso aproximado de 221 kg, distribuídos aleatoriamente em dois tratamentos: dieta formulada com minerais orgânicos e dieta formulada com minerais inorgânicos, com cinco repetições por tratamento. A dieta foi composta de 40% de volumoso, feno de gramínea e 60% de concentrado, a qual foi adicionada 3% da mistura mineral orgânico ou inorgânico. Não foi observada diferença entre os tratamentos em relação ao consumo da deita, medidas de crescimento, e deposição óssea de cálcio e fósforo. No entanto, a deposição óssea dos animais do tratamento orgânico foram maiores quando comparada com as médias do tratamento inorgânico. Entretanto para a variável densitometria, a deposição óssea dos potros alimentados com fonte orgânica foi maior aos 90 dias, quando comparado com todos os animais do tratamento com fonte inorgânica. Os animais do tratamento orgânico apresentaram melhor ganho de peso médio e diário em relação aos animais que receberam mineral inorgânico. / The aim of this study was to evaluate the effects of mineral organic in the diet of foals, evaluating the bone mineral deposit of calcium and phosphorus, throughout biopsy and bone mineral density, measures of growing was also did measuring height withers and croup, thoracic circumference, knee, cannon and weight gain. Ten foals which approximated 10 and 13 months and almost 221 Kg weight each one were spread randomly into two treatments: diet with organic mineral and diet with inorganic mineral both with five repetitions for treatments. The diet were composed by 40% of roughage and 60% for concentrate, with was addition 3% of mixed mineral organic or inorganic. It was not detected any for consumption of diet, either for measures of growing and bone mineral concentration of calcium and phosphorus. Nevertheless, the average bone mineral concentration for organic treatment was better than mineral inorganic supplementation. However, the concentration in bone mineral was greater for organic treatment which was better for bone mineral density and weight. The bone deposition was better in 90 days of treatment. Therefore, the diet with organic mineral for foals probably better for bone mineral density and weight gain.

Diante da importância do zinco no desempenho produtivo e reprodutivo de matrizes suínas, e no desempenho de leitões, foram conduzidos três experimentos com o objetivo de avaliar diferentes fontes de zinco na alimentação de suínos. O experimento I avaliou diferentes fontes de zinco, orgânico (zinco+metionina ((Zn-Met) e zinco+glicina(Zn-Gli)) e inorgânico (óxido de zinco(ZnO)) na dieta de matrizes em gestação e lactação e os efeitos do uso destas fontes na sua progênie. Foram utilizadas 18 fêmeas de uma linhagem comercial distribuídas em delineamento experimental de blocos ao acaso, com três tratamentos e seis repetições de um animal. As características avaliadas nas matrizes foram: peso, espessura de toucinho, prolificidade, número de leitões nascidos vivos e níveis séricos de zinco no colostro e no leite. Para os leitões após parto até a desmama foram analisados: níveis de zinco no soro, ganho de peso, histomorfologia entérica e densidade óssea. No experimento II foram utilizados 180 leitões, desmamados com 21 dias de idade, distribuídos em delineamento de blocos ao acaso em esquema fatorial 3 x 3 (3 dietas maternas - 100 ppm de ZnO, Zn-Met, Zn-Gli x 3 dietas da progênie - 100 ppm de ZnO, Zn-Met, Zn-Gli) totalizando 9 tratamentos e 5 repetições de 4 animais cada, em que foram avaliados o desempenho, incidência de diarréia, níveis de zinco no soro, densidade óssea e histomorfologia entérica No experimento III foram utilizados 810 leitões, desmamados com 21 dias de idade, distribuídos em delineamento de blocos ao acaso com 6 tratamentos de 3 repetições de 45 animais: Fases I e II - 1. dieta + 2300 ppm de ZnO; 2. dieta + 2200 ppm de ZnO + 100 ppm de Zn-Met; 3. dieta + 2200 ppm de ZnO + 100 ppm de Zn-Gli; 4. dieta + 2400 ppm de ZnO; 5. dieta + 2200 ppm de ZnO + 200 ppm de Zn-Met; 6. dieta + 2200 ppm de ZnO+200 ppm de Zn-Gli; Fase III - 1. dieta + 1600 ppm de ZnO; 2. dieta + 1500 ppm de ZnO + 100 ppm de Zn-Met; 3. dieta + 1500 ppm de ZnO + 100 ppm de Zn-Gli; 4. dieta + 1700 ppm de ZnO; 5. dieta + 1500 ppm de ZnO + 200 ppm de Zn-Met; 6. dieta + 2200 ppm de ZnO+200 ppm de Zn-Gli, em que avaliou-se o desempenho dos animais. Os dados foram analisados utilizando o programa SAS (1998). As médias dos tratamentos foram comparadas pelo teste de Tukey ao nível de 5% de probabilidade, segundo Steel e Torrie (1980). / Given the importance of zinc in the productive and reproductive performance of sows and piglets performance, three experiments to evaluate different sources of zinc in swine were conducted. The first experiment evaluated different sources of zinc, organic (zinc methionine (Zn-Met) and zinc glycine (Zn-Gly)) and inorganic (zinc oxide (ZnO)) in the diet of pregnant gilts and sows lactating and the effects of using these sources in their progeny. Were used 18 female of a commercial strain distributed in experimental design of randomized blocks with three treatments and six repetitions with one animal each. The characteristics evaluated in the sows were: weight, backfat thickness, prolificacy, number of piglets born alive and zinc levels in serum, colostrum and milk; In the piglets after birth until weaning were analyzed: serum levels of zinc, weight gain, bone density and histomorphology enteric. The second experiment 180 piglets were used, weaned at 21 days of age in a randomized block design in a factorial 3 x 3 (3 maternal diets - 100 ppm from ZnO , Zn-Met , Zn-Gly x 3 diets progeny - 100 ppm ZnO , Zn-Met - , Zn-Gly) totaling 9 treatments and 4 replicates of 5 animals each, which evaluated the performance, diarrhea incidence, serum zinc levels, bone density and histomorphology enteric. The third experiment 810 weaned pigs weaned at 21 days of age in a randomized block design with 6 treatments of 3 replicates of 45 animals each: Phases I and II - 1. diet + 2300 ppm of ZnO; 2. diet + 2200 ppm of ZnO + 100 ppm of Zn-Met; 3. diet + 2200 ppm ZnO + 100 ppm of Zn-Gly; 4. diet + 2400 ppm of ZnO; 5. diet + 2200 ppm of ZnO + 200 ppm of Zn- Met; 6. diet + 2200 ppm of ZnO + 200 ppm of Zn-Gly; Phase III - 1. diet + 1600 ppm of ZnO; 2. diet + 1500 ppm of ZnO + 100 ppm of Zn-Met; 3. diet + 1500 ppm of ZnO + 100 ppm of Zn-Gly; 4. diet + 1700 ppm of ZnO; 5. diet + 1500 ppm of ZnO + 200 ppm of Zn- Met; 6. diet + 2200 ppm of ZnO + 200 ppm of Zn-Gly in evaluating the performance of animals. All datas were analyzed using SAS (1998 ) program. The treatment means were compared by Tukey test at 5 % probability , according to Steel and Torrie (1980).

Although there are now many theories describing empirical relationships between strength properties of bone and various explanatory variables, the need for improved non-invasive diagnostic techniques to assess bone fragility is of core importance in clinical problems such as osteoporosis. The aim of this thesis was to develop non-invasive radiological methods to assess trabecular bone architecture. Measures of structural anisotropy and bone structure from X-ray or radiological projections have been developed. The first measure, the projected mean intercept length (PMIL), allows extraction of the total bone surface (BS/TV) and the mean intercept length (MIL) from projections of trabecular structure. The second measure, the line projection deviation (LPD), is a technique that quantifies the preferential alignment of trabecular bone from projections of the trabecular structure. Hence, in combination, the PMIL and LPD allow non-invasive extraction of BS/TV and more detailed preferential alignment from projections of the trabecular structure. In this thesis the PMIL and LPD are introduced and their properties explored. The PMIL and LPD are used to examine the anisotropy and architectural properties of a number of human vertebral body trabecular bone samples. When used in combination with clinical densitometry, these measures improve explanation of the variance in strength, elastic modulus and toughness of vertebral body trabecular bone samples by up to 40% when compared to densitometric values alone. While µCT can provide the information needed to access trabecular architecture, it cannot be used in clinical settings since its high radiation dose makes it only applicable to small objects ex-vivo. At present, clinically available CT does not provide sufficient resolution to resolve trabecular structures. Thus, the methods described in this thesis will allow estimates of structural parameters from plain X-rays, providing for the first time, the possibility of clinical use of such estimates. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1311218 / Thesis (Ph.D.) -- School of Medical Sciences, 2008

Sex differences in bone mass and size are thought to contribute to the greater incidence of vertebral fractures in women. While these sex differences are widely recognized, the relative contributions of bone mass, bone density, and bone size to the differences in vertebral strength and fracture risk between men and women have not been fully delineated. Furthermore, it is unknown whether the roles of each of these factors in determining vertebral strength change differently with age in men and women. We studied the bone content, density and geometry as well as vertebral loading and the factor of risk of the L3 vertebra in a sample of prepubertal males and females. Our first aim was to assess differences in vertebral bone dimensions, bone density, vertebral loading patterns and fracture risk, as measured by the factor of risk, in prepubertal children. Our second aim was to determine whether pre-pubertal growth affects the geometry and density of L3 differently in boys and girls. We measured vertebral dimensions, cross-sectional area and volumetric BMD of the third lumbar vertebral body in 93 prepubertal children (54 boys and 39 girls), using dual-energy X-ray absorptiometry scans obtained in the posterior-anterior and lateral projections. We also employed basic biomechanics to estimate vertebral loading during upright standing and forward bending. Bone strength and loading data were used to assess sex differences in the factor of risk in prepubertal children. Twenty children (11 boys and 9 girls) were assessed at baseline and seven months later to examine the effects of growth on bone size and vBMD. At baseline, boys and girls were similar for age, height, weight and calcium intake. L3 width and depth were 6.7% and 5.8% greater in boys than girls, respectively (P<0.001 and P=0.01, respectively). In contrast, vertebral height was 3.5% greater in girls than boys (P= 0.04). While vertebral loading was similar between sexes, stresses on the spine were 12.2% lower in boys during upright standing and 12.0% lower in boys during forward bending at both 50° and 90°, as compared to girls (P<0.001, P<0.01 and P<0.01, respectively). The factor of risk was similar between boys and girls under each loading condition. During growth, changes in vertebral size and density were not different between boys and girls. Our results indicate that even prior to puberty, sex differences in vertebral size contribute to differences in vertebral stress during standing and forward bending. Furthermore, before the onset of puberty, growth does not result in disparate changes between sexes. / Graduation date: 2004

Studies in young women show that rowing exercise is osteogenic at the spine. However, little is known regarding rowing exercise and spine bone mineral density in older women. The aim of this study was to examine differences in spine bone mineral density (BMD) and back strength between premenopausal and postmenopausal competitive female masters rowers (n=28, 45.5 ± 4.7 yrs, n=28, 56.1 ± 5.7 years, respectively) and age-matched non-rowers (n=30, 43.3 ± 4.2 yrs; n=26, 56.8 ± 4.8 years). Competitive rowers were recruited from nine rowing clubs in the local area and compared to controls recruited from the same region who were normally active but not participating in rowing activity. Participating rowers had been engaged in competitive rowing for a minimum of one year. The average years spent rowing for the premenopausal and postmenopausal groups was 7.5 ± 6.6 yrs and 5.9 ± 6.9 yrs, respectively. BMD (g/cm²) of the third lumbar vertebrae (L3) was measured by dual-energy x-ray absorptiometry (DXA) in both the anterior-posterior and lateral views. Back strength was assessed using a standing cable tensiometer. Subjects also completed questionnaires to assess diet, physical activity, medical history and rowing history. Differences in BMD and back strength between groups were determined by analysis of covariance, controlling for lean mass. Compared to controls, postmenopausal rowers had 3.2% higher BMD at the anterior-posterior spine (p=.02) and 4.4% higher lateral spine BMD (p=.04). Furthermore, isometric back strength was 22.6% greater in these rowers than controls (p=.01). In contrast, controls had higher lateral BMD than rowers, with no differences in AP spine BMD or back strength between the premenopausal rowers and controls. Back strength was a significant predictor of AP spine BMD in premenopasual rowers and controls (R²=0.137, p=0.004) and of lateral spine BMD in postmenopausal rowers only (R²=0.153, p=0.04). There were no differences in calcium intake, age, menopausal status, weight, or lean mass between rowers and controls in either the premenopausal or postmenopausal samples. Since both increased BMD and back strength are associated with reductions in vertebral fracture risk, our results suggest that rowing exercise may be an important strategy to promote bone health and reduce vertebral fracture risk in postmenopausal women. However, the forces applied in rowing may not be great enough to alter bone mass before the onset of menopause. Therefore more research is needed examining rowing exercise in these older populations. / Graduation date: 2005

Discordance in bone mass between young adult swimmers and soccer players may be a direct result of differences in bone loading patterns that influence bone mineralization during growth. Our aim was to evaluate whether sports participation (soccer and swimming) had an independent effect on bone mass accrual at the hip and lumbar spine in adolescent female athletes. We recruited boys and girls 10 to 14-years of age from Corvallis, Albany, Sweet Home, Salem, Eugene, and the greater Portland area. Bone mineral content (BMC, g) and bone mineral density (BMD, g/cm²) of the proximal left hip, spine, and whole body were assessed by dual energy x-ray absorptiometry (Hologic QDR 4500A; Hologic Inc., Waltham, MA, USA). We used ANCOVA and report that baseline BMC and BMD values of girl soccer players at the greater trochanter were significantly higher compared to controls and the swim group, and femoral neck BMC was significantly greater than the swimmers. At baseline, all boy groups were similar at the hip and spine. After 12-months, ANCOVA was also used to assess absolute change for BMC and BMD at the hip and spine. The girl soccer players had significantly more BMC and BMD at the greater trochanter as well as total hip BMD and lumbar spine BMC compared to the swimmers, but not the controls. The girl control group showed a significantly greater 12-month change for femoral neck and greater trochanter BMC than swimmers. Overall, the girl swimmers demonstrated a lower accumulation of bone mass during the 12-month study period. As for the boys, soccer players had a significantly higher 12-month change for femoral neck BMC than swimmers, but were similar at the spine. There were no differences between the boy control subjects and the swimmers for 12-month change values at the hip and spine. While preliminary and limited by the small sample size, our results indicate that after controlling for growth, soccer players gained significantly more BMC at the femoral neck than swimmers. Furthermore, exposing the young skeleton to impact loading exercise has site-specific benefits at the hip whereas prolonged training in a non-weight bearing environment may compromise skeletal acquisition. / Graduation date: 2004

In the United States, falls are the leading cause of unintentional death with one of every three people 65 years and older falling each year. Falls account for approximately 95% of hip fractures among older adults and falls to the side predominate hip fracture related falls in this population. However, risk factors for side and frequent falls are poorly understood. Furthermore, few data exist to explain differences in bone mineral density among older postmenopausal women. In particular, data regarding the timing of hormone replacement therapy (HRT) among older women is scarce. In the first aim of this dissertation, we examined changes in mobility and balance-related risk factors for side falls as well as differences in these risk factors according to fall status in a population of 107 independent, elderly women (>70 yrs), who were followed over 2 years. We found hip abduction strength decreased (p<.001) in all subjects, with side-fallers exhibiting weaker hip abduction strength (p=.008), greater sway velocity (p=.027), and slower performances on the tandem walk (p=.039) and Get Up and Go (p<.001) compared to non-fallers. For the second study, in the same population, we examined 2-year changes in balance self-efficacy (BSE) and the relationship of BSE to side fall risk factors and falls incidence. Results showed BSE at baseline was predictive of Get Up and Go, hip abduction strength and tandem walk at follow-up (p<.008), but that BSE decreased only among the non-fallers (p=.013). In the third study, we examined 3-yr hip bone mineral density (BMD) changes in women with distinct hormone replacement therapy (HRT) profiles: 1) no hormone replacement therapy (N0HRT), 2) HRT continually since menopause (Continual), 3) HRT begun 10 years after menopause (Late), 4) HRT initiated within 5 years (New), and compared the change in BMD of the hip across HRT groups. Only the NoHRT group lost bone over the 3 years (p=.014). We also assessed BMD of the lateral spine across levels of estrogen use in a sub-sample of participants and found long-term HRT users had significantly higher lateral spine BMD (p=.041) compared to women who had never been on HRT. / Graduation date: 2003

This study was designed to investigate the relationship between retinol intake, bone mineral density, and falls in 101 elderly women aged 72 to 90 years (78.6 yrs. �� 4.3 yrs.). Bone mineral density (BMD) (g/cm��) of the left hip, anterior-posterior lumbar spine (L3), and lateral spine (L3) was measured using dual-energy x-ray absorptiometry. Dietary intake and physical activity were assessed by validated questionnaires (the 100-item Block Food Frequency Questionnaire and the Physical Activity Scale for the Elderly, respectively). Isometric hip abduction strength of the right and left legs was assessed using a hand-held dynamometer. Fall surveillance was collected using a "postcard" system at three-month intervals over a two-year period. Multiple regression analyses were used to show the predictability of retinol, vitamin D, calcium, years past menopause, years on hormone replacement therapy, and physical activity on BMD variables. Together, these variables explained 14% of the variance in total hip BMD at follow-up (R��=0.14, SEE=0.12, p=0.020), 26% of the variance in the anterior-posterior spine BMD at follow-up BMD (R��=0.26, SEE=0.17, p=0.051), and 33% of the variance in lateral spine BMD at follow-up (R��=0.33, SEE=0.10, p=0.009). Two-year changes in hip BMD were poorly predicted using the model with only 5% of total hip BMD variance being explained by the six independent variables (R��=0.05, SEE=0.03, p=0.558). Logistic regression was used to determine whether the likelihood of being a faller vs. a non-faller could be predicted from a model using retinol, vitamin D, average hip strength, and physical activity. It was shown that 11.5% of the variability in fall status could be explained by the model (Cox & Snell's R��=0.115). Using an ROC curve analysis, the model correctly classified 69% of the individuals into the correct "fall category". We conclude that retinol, although not an independent predictor of BMD or fall status, is an important component in the prediction of both BMD and falls. Further interventional research is needed to determine the effects of retinol on BMD and falling. / Graduation date: 2004

We evaluated anthropometric and performance measures which best predict bone mineral density (BMD) in 54 adolescent girls (14.6��0.5y; 22.7��14.0 months past menarche). BMD for the whole body, femoral neck, greater trochanter, lumbar spine (L2-L4), and mid-femoral shaft was assessed using dual-energy x-ray absorptiometry (DXA) (Hologic QDR 1000/W). Whole body lean mass and fat mass were derived from the whole body scan. Knee extensor strength and leg power were assessed by isokinetic dynamometry and the Wingate Anaerobic Power Test, respectively. Using simple regression, lean mass was significantly correlated with BMD at all bone sites r=.45-.77; p<0.001), and was more highly correlated with BMD at all sites than was body weight. Maximum leg power was also associated with bone mass at all sites (r=.41-.67; p<0.001) while leg strength correlated significantly with all sites (r=.41-.53; p<0.001) except the lumbar spine. Stepwise regression analyses revealed that 59% of the variance in whole body BMD was predicted by lean mass alone. No other variables, including fat mass, height, months past menarche, leg power, or leg strength, contributed additionally to the regression model. Similarly, lean mass was the only predictor of lumbar spine and femoral shaft BMD (R��=.25, R��=.37, respectively), while femoral neck and trochanteric BMD were best predicted by leg power (R��=.38, R��=.36, respectively). In this group of adolescent girls, lean body mass and leg power independently predicted bone mineral density of the whole body, lumbar spine, femoral shaft, and hip, which may suggest an important role for muscle mass development during growth to maximize peak bone density. / Graduation date: 1997