PURPOSE: To establish the reliability of anthropometric and dual energy X-ray absorptiometry(DXA) techniques used to assess percent body fat (% BF)in female athletes; to establish limits for detecting the smallest real change in % BF associated with anthropometric and DXA testing;to evaluate the validity of commonly used % BF prediction equations recommended by national certification programs along with equations derived from Multicompartment (MC), and DXA, in female athletes; and to create a new DXA based regression equation for elite female athletes. METHODS:Female athletes aged 17-31 were recruited into the study and participated in the establishment of anthropometric reliability (N=20), DXA reliability (N=32), and /or skinfold validity (N=95) testing. Anthropometric testing consisted of measurements of skinfolds,circumferences, and breadths. DXA measurements were conducted using a GE Lunar Prodigy DXA which served as the criterion measure (% BF DXA). RESULTS: Excellent reliability for both anthropometric sum5 skinfolds (ICC= .997, %TEM=0.9 %) and DXA (ICC =.996, CV =1.13% BF) techniques allows for detection of smallest real differences of 2.2 mm and 721g in summed skinfolds (sum5) and fat mass respectively. The DXA based equation of Ball et al.(2004) displayed the greatest validity of existing equations R=.874, total error (TE) 2.9% BF, and Bland Altman Limits of Agreement -4.7to 6.5 % BF. The newly created regression equation demonstrated a non-linear characteristic and displayed similar predictive ability R= .840, TE 3.0%BF, and Bland Altman Limits of Agreement of -6.1to 6.1 % BF. CONCLUSIONS: Anthropometric equations derived from various criteria yielded dissimilar results. Long utilized popular equations advocated in national accreditation schemes (ACSM, CSEP) show considerable bias compared to modern values obtained by current DXA technology. A new regression equation was created for female Canadian athletes 17-31yrs of age using skinfolds taught in the Canadian national professional certification program (CSEP).

In this thesis, a two-dimensional (2D) finite element (FE) model was developed from the patient’s hip DXA image to evaluate osteoporotic fracture risk. The loading configuration was designed to simulate a lateral fall onto the greater trochanter. Bone inhomogeneous mechanical properties (e.g. Young’s modulus) assigned to the FE model were correlated to bone mineral density captured in DXA image using empirical functions. In-house MATLAB codes were developed to investigate the effects of different factors such as bone mineral density, femoral neck length, neck diameter, neck angle and patient’s body weight on fracture risk. The 2D FE model constructed from DXA image was able to de-termine the factors which affect fracture risk to a greater extent based on the location of femur. The model developed here can be considered as a first attempt for investigating the effects of different parameters on fracture risk using patient specific 2D FE method.

The function of skeletal adaptation to mechanical load is to adjust the amount and distribution of bone tissue (geometry); such that stresses experienced within the bone are kept within certain physiological limits and fractures are prevented. Genetic, environmental or hormonal factors may cause heterogeneity in this adaptive response, altering geometry and consequently fragility. The purpose of this thesis was to explore the skeletal response to load in vivo, by evaluating stress at the hip under three different conditions: FRACTURE (Study 1), DIABETES (Study 2) and ESTROGEN deficiency (STUDY 3). We studied women 25 years of age or older who participated in the Canadian Multicentre Osteoporosis Study and had available Hip Structure Analysis (HSA) data from baseline dual energy x-ray absorptiometry (DXA) scans. Women were categorized according to fracture status (fracture or no fracture), diabetes status (diabetes or no diabetes) and estrogen use (current users or never users). We computed stress (megapascals=MPa) at the infero-medial margin of the femoral neck in a one-legged iii stance using a 2-D engineering beam analysis. We used linear regression to determine associations between femoral neck stress and each categorical variable. Study 1 (n=2168) demonstrated higher stresses in postmenopausal women with fractures compared to women without fractures (10.57 ± 2.19 vs. 10.30 ± 2.03 MPa; p=0.0031). Study 2 (n=3665) demonstrated higher stresses in women with Type 2 Diabetes Mellitus compared to non-diabetic women (10.98 ± 2.33 vs. 10.57 ± 2.20 MPa; p=0.0194). Study 3 (n=2447) demonstrated higher stresses in postmenopausal women not on estrogen than in premenopausal women (10.66 ± 2.14 vs. 10.09 ± 2.01 MPa; p<0.0001), but no differences in stresses between postmenopausal women on estrogen and premenopausal women (10.16 ± 2.00 vs. 10.09 ± 2.01 MPa; p=0.6102). Since stress is an indicator of underlying geometry, and geometry should be adapted to prevalent loads, higher stress indicates weaker geometry and suggests an impaired modeling response in these three conditions. Compromised modeling has important clinical implications in terms of treatment selection, as individuals with reduced load sensitivity may respond best to metabolic agents that would improve modeling responses to load stimuli.

The function of skeletal adaptation to mechanical load is to adjust the amount and distribution of bone tissue (geometry); such that stresses experienced within the bone are kept within certain physiological limits and fractures are prevented. Genetic, environmental or hormonal factors may cause heterogeneity in this adaptive response, altering geometry and consequently fragility. The purpose of this thesis was to explore the skeletal response to load in vivo, by evaluating stress at the hip under three different conditions: FRACTURE (Study 1), DIABETES (Study 2) and ESTROGEN deficiency (STUDY 3). We studied women 25 years of age or older who participated in the Canadian Multicentre Osteoporosis Study and had available Hip Structure Analysis (HSA) data from baseline dual energy x-ray absorptiometry (DXA) scans. Women were categorized according to fracture status (fracture or no fracture), diabetes status (diabetes or no diabetes) and estrogen use (current users or never users). We computed stress (megapascals=MPa) at the infero-medial margin of the femoral neck in a one-legged iii stance using a 2-D engineering beam analysis. We used linear regression to determine associations between femoral neck stress and each categorical variable. Study 1 (n=2168) demonstrated higher stresses in postmenopausal women with fractures compared to women without fractures (10.57 ± 2.19 vs. 10.30 ± 2.03 MPa; p=0.0031). Study 2 (n=3665) demonstrated higher stresses in women with Type 2 Diabetes Mellitus compared to non-diabetic women (10.98 ± 2.33 vs. 10.57 ± 2.20 MPa; p=0.0194). Study 3 (n=2447) demonstrated higher stresses in postmenopausal women not on estrogen than in premenopausal women (10.66 ± 2.14 vs. 10.09 ± 2.01 MPa; p<0.0001), but no differences in stresses between postmenopausal women on estrogen and premenopausal women (10.16 ± 2.00 vs. 10.09 ± 2.01 MPa; p=0.6102). Since stress is an indicator of underlying geometry, and geometry should be adapted to prevalent loads, higher stress indicates weaker geometry and suggests an impaired modeling response in these three conditions. Compromised modeling has important clinical implications in terms of treatment selection, as individuals with reduced load sensitivity may respond best to metabolic agents that would improve modeling responses to load stimuli.

Orientador: Silvana Regina Perez Orrico / Banca: Luis Carlos Spolidorio / Banca: Marcio Fernando de Moraes Grisi / Resumo: O presente estudo teve como objetivo avaliar possíveis alterações na densidade mineral óssea mandibular e femoral decorrentes da deficiência de estrógeno promovida pela ooforectomia (OVX), e a influência dessas alterações sobre a doença periodontal induzida em ratas. Quarenta e oito ratas, Holtzman, com idade de 90 dias, foram distribuídas em 5 grupos: Grupo controle (n=9), Grupo 1- "SHAM" sem indução de doença periodontal (n=11), Grupo 2- "SHAM" com indução de doença periodontal (n=10), Grupo 3- OVX sem indução de doença periodontal (n=9) e Grupo 4- OVX com indução de doença periodontal (n=9). Nove animais foram sacrificados no dia zero; 18 foram submetidos à cirurgia de OVX e 21 à cirurgia simulada ("SHAM"). Para os animais pertencentes aos grupos 2 e 4, após um período de 120 dias, foram colocadas ligaduras de fio de algodão nos primeiros molares inferiores as quais permaneceram por um período de 30 dias. Finalizado o período de 5 meses, os animais foram mortos sendo removidos a mandíbula, o fêmur e o útero. Foram efetuadas medidas de BMD global e de sub-regiões, da mandíbula e do fêmur, assim determinadas: hemimandíbula: global; R1 - região do côndilo mandibular; R2 - bordo inferior do corpo mandibular e R3 - região incisal da mandíbula e para o fêmur: global; R1 - epífise distal; R2 - epífise proximal e R3 - diáfise. Foram avaliadas, por meio de radiografias digitais, a presença ou ausência de perda óssea vertical, medindo-se a distância da crista óssea à junção cemento-esmalte na mesial do primeiro molar inferior. A análise dos resultados do fêmur diferença estatisticamente significativa entre os grupos "SHAM" e "OVX" quanto aos valores medianos de densidade óssea, para todas as regiões. A comparação entre os grupos Controle, "SHAM" e OVX em relação à BMD da mandíbula nas regiões R1, R2, R3 e Global... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: This study had the objective to assess possible changes in mandibular and femoral bone mineral density resulting from estrogen deficiency due to ovariectomized, and the influence of these alterations of the periodontal disease induced in rats. Forty eight rats Holtzman, at the age of 90 days, were distributed in 5 groups: control group (n=9), group 1- "SHAM" without inducement of periodontal disease (n=11), group 2- "SHAM" with inducement of periodontal disease (n=10), group 3- OVX without inducement of periodontal disease (n=9) and group 4- OVX with inducement of periodontal disease (n=9). Nine animals were sacrificed on day 0 (baseline); 18 of them were subjected to OVX surgery and to "SHAM" simulate surgery. For the animals belonging to group 2 and 4, after a period of 120 days, were placed ligatures first inferior molar, wich remained on for 30 days. At the end of 5 months, the animals were killed and the mandible, femur and uteri were excised. Measures of BMD global and sub-regions of the mandible and femur were taken such as, mandible: global; R1 - condylar region; R2 - inferior border of mandible, and R3 - incisal region of mandible and for femur: global; R1 - distal epiphysis; R2 - proximal epiphysis and R3 - diaphysis. The presence or absence of the vertical loss bone was assessed by digital radiography, measuring the distance of the bone crest to the cementodentinal junction in the mesial of first inferior molar. The analysis of the femur results gives us evidence that there is a significant difference in median values of bone density between the groups "SHAM" and OVX, for all the regions. The comparison between the groups control, "SHAM" and OVX in relation to BMD of mandible in the region R1, R2, R3 and global, didn't show any significant difference (p>0,05) between themselves. The measures of... (Complete abstract, click electronic address below). / Mestre

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-10-05T00:08:46Z No. of bitstreams: 1 JonatasCardosoDaSilveira_DISSERT.pdf: 960551 bytes, checksum: 6a74842dfe817418a8368241ea11424f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-10-16T21:23:01Z (GMT) No. of bitstreams: 1 JonatasCardosoDaSilveira_DISSERT.pdf: 960551 bytes, checksum: 6a74842dfe817418a8368241ea11424f (MD5) / Made available in DSpace on 2017-10-16T21:23:01Z (GMT). No. of bitstreams: 1 JonatasCardosoDaSilveira_DISSERT.pdf: 960551 bytes, checksum: 6a74842dfe817418a8368241ea11424f (MD5) Previous issue date: 2017-03-31 / A distribui??o de massa de um indiv?duo est? fortemente relacionada com os n?veis gerais de sa?de e condicionamento f?sico do mesmo. Para Mouad e Matias (2015), atrav?s da composi??o corporal (CC) ? poss?vel saber informa??es como tamanho, forma, constitui??o e caracter?sticas gen?ticas e adquiridas da pessoa ou at? mesmo de uma popula??o. Objetivo: Testar a validade de predi??o da massa livre de gordura de atletas universit?rios de futebol por equa??es de bioimpedanciometria, utilizando a Absortometria de Raios X de Dupla Energia como padr?o. M?todos: A amostra foi composta por 39 homens, da sele??o de futebol universit?ria da Universidade Federal do Rio Grande do Norte. As medidas de DXA e da BIA foram coletadas no mesmo dia no laborat?rio da institui??o. Para c?lculo de composi??o por BIA foi utilizado um software da Biotetronic, que propos as equa??es de Segal et. Al. (1988), Gray et. Al. (1989), Lohman (1992) e Carvalho e Neto (1998). Na an?lise dos dados foi verificada suanormalidade, e efetuada an?lise descritiva de m?dia e desvio padr?o, test T de Student para amostra dependentes (p < 0,05), modelos de regress?o linear, coeficientes de correla??o de Pearson (R), os coeficientes de determina??o (R2) e o erro padr?o de estimativa (EPE), assim como o coeficiente de correla?ao de concord?ncia (CCC), al?m do m?todo de Bland Altman. Conclus?o: Os resultados sugerem que para todas as equa??es, propostas pelo software da BIA, quando comparadas ao m?todo de referencia (DXA) os coeficientes de correla??o e concord?ncia foram classificados como fracos. Havendo ainda a necessidade de produ??o de novas equa??es que atendam ao estudo de uma popula??o espec?fica ou maior controle de in?meras vari?veis capazes de alterar os n?veis de resist?ncia e reat?ncia do sujeito naquele momento. / The distribution of mass of is strongly related with the general levels of health and physical conditioning. For Mouad and Matthias (2015), through the body composition (BC) it is possible to know information such as size, shape, composition and genetic traits and acquired by the person or even of a population. Objective: Test the validity of prediction of fat-free mass of soccer athletes by equations of bioimpedanciometry, using the Absortometry of dual-energy X-ray as a default. Methods: The sample was composed of 39 men, of the college soccer team of Universidade Federal do Rio Grande do Norte. The measures of DXA AND BIA were collected on the same day in the laboratory of the institution. For calculation of composition by BIA was used software from Biotetronic, who proposed the equations of Segal et al. Al. (1988), Gray et al. Al. (1989), Lohman (1992) and Carvalho and Neto (1998). In the analysis of data was verified the normality, and performed a descriptive analysis of media and, standard deviation test T-Test for dependent samples (p < 0.05), linear regression models, Pearson correlation coefficients (R), the coefficient of determination (R2) and the standard error of estimate (EPE), as well as the coefficient of correlance of concordance (CCC), in addition to the method of Bland Altman. Conclusion: The results suggest that for all the equations proposed by the software of the BIA, when compared to the method of reference (DXA) the coefficients of correlation and concordance were classified as weak. There is still need for production of new equations that meet the study of a specific population or greater control of numerous variables that can alter the levels of resistance and reactance of the subject at that moment.

Hip fracture is the leading cause of acute orthopaedic hospital admission amongst the elderly, with around a third of patients not surviving one-year post-fracture. Current risk assessment tools ignore cortical bone thinning, a focal structural defect characterizing hip fragility. Cortical thickness can be measured using computed tomography, but this is expensive and involves a significant radiation dose. Dual-energy X-ray absorptiometry (DXA) is the preferred imaging modality for assessing fracture risk, and is used routinely in clinical practice. This thesis proposes two novel methods which measure the cortical thickness of the proximal femur from multi-view DXA scans. First, a data-driven algorithm is designed, implemented and evaluated. It relies on a femoral B-spline template which can be deformed to fit an individual?s scans. In a series of experiments on the trochanteric regions of 120 proximal femurs, the algorithm?s performance limits were established using twenty views in the range 0? ? 171?: estimation errors were 0.00 ? 0.50 mm. In a clinically viable protocol using four views in the range ?20? to 40?, measurement errors were ?0.05 ? 0.54 mm. The second algorithm accomplishes the same task by deforming statistical shape and thickness models, both trained using Principal Component Analysis (PCA). Three training cohorts are used to investigate (a) the estimation efficacy as a function of the diversity in the training set and (b) the possibility of improving performance by building tailored models for different populations. In a series of cross-validation experiments involving 120 femurs, minimum estimation errors were 0.00 ? 0.59 mm and ?0.01 ? 0.61 mm for the twenty- and four-view experiments respectively, when fitting the tailored models. Statistical significance tests reveal that the template algorithm is more precise than the statistical, and that both are superior to a blind estimator which naively assumes the population mean, but only in regions of thicker cortex. It is concluded that cortical thickness measured from DXA is unlikely to assist fracture prediction in the femoral neck and trochanters, but might have applicability in the sub-trochanteric region.

Introduction: Metaphyseal inwaisting is a process that occurs during long bone growth and remodelling of epiphyses and results in a proportional increase in growth plate width (GPW) and a decrease in metaphyseal width (MW). The Metaphyseal Index (MI) compares GPW to MW, usually in the distal femur. However, due to bone-age assessments, the most commonly performed radiograph in children is that of the hand/forearm. Previous work showed that gymnasts have a more widened growth plate at the distal radius than normal children, but these studies did not quantify the morphological changes using the MI and pQCT measures. Previous studies have shown that the use of DXA hand/forearm images for the purposes of bone-age assessment were unreliable for children aged 11 and under. Aims: Examine distal radius morphology of 378 Normal subjects (155 male), 36 Gymnast subjects (15 male), 17 NF1 subjects (7 male) and 108 CDGP subjects (83male) to calculate the precision of MI, MW and GPW measurements, to determine a normal reference range for the MI in Normal subjects and use this to compare to the other 3 groups, and to compare longitudinal measurements. Also, to investigate whether DXA software upgrades have improved the ability to make TW3 bone-age assessments, to investigate how closely DXA compares with standard radiographs using 98 (38 male) DXA hand images and radiographs, and calculate the precision (CV%) of the GP and TW3 bone-age assessment methods. Methods: Anthropometric data, Tanner stage, posterior-anterior hand radiographs and pQCT scans of the non-dominant hand/forearm were obtained. MI was measured using a semi-automated computer-assisted method. Statistical analyses were used to compare males and females, and compare the Normal group to other groups. Also, DXA images and radiographs were assessed by the same assessor and the TW3 and GP bone-ageing methods were compared. A CV% was calculated for both comparisons. Results: The CV% of MI, MW and GPW = 1.05%, 0.92% and 1.28% respectively. MI of males and females was not statistically different in any group. The MI of Gymnasts was significantly lower than the Normal group (p = 0.008). The NF1 and CDGP groups were not significantly different from the Normal group. Longitudinal measurements indicated those with a low/high MI at the first visit were likely to have a low/high MI at the second visit, though occasionally the MI would decrease between visits. DXA bone age assessments proved to be reliable in subjects of all ages assessed in this study and showed a CV% only slightly higher than standard radiographs (CV = 2.95% DXA vs2.68% radiograph). The CV% of GP and TW3 methods = 2.68% & 1.61% respectively. Discussion: The CV% of MI, MW and GPW shows these methods to be very precise. The mean MI of gymnasts is significantly lower than in normal children due to a widening of the growth plate and not due to a reduction in metaphyseal width. Insufficient subject numbers and smaller age ranges, particularly in the Gymnast and NF1 groups may play a part in the non-significant differences between them and the Normal group. DXA CV% shows that DXA is almost interchangeable with standard radiographs. The TW3 and GP CVs% show that TW3 bone-age assessment is more precise than the GP method. This confirms the tight control that the MW and GPW have in proportion to each other. This is the first study to quantify changes in distal radius morphology in normal, athlete and disease groups, and create a range of normal reference values, which could be useful for future work in this area.

Currently, about 1 in 3 women of reproductive age are obese (Flegal, Kruszon-Moran, Carroll, Fryar, & Ogden, 2016). Obesity in pregnancy has been associated with adverse maternal and infant outcomes (“Clinical Management Guidelines for Obstetrician–Gynecologists. Number 49, December 2003,” 2003) and maternal overweight and obesity have been implicated as increasing the risk for early childhood obesity (Ramonienė et al., 2017). Obesity is defined by the World Health Organization as having a body mass index (BMI) greater than 30 kg/m2, however, there is mounting evidence that BMI is not an accurate measure of adiposity (Kennedy, Shea, & Sun, 2009), which is one of the leading clinical concerns surrounding obesity. Understanding the associations between maternal body composition and infant body composition could begin to answer questions regarding the underpinnings of intergenerational obesity and offer a modifiable factor such as body composition as a target of opportunity to improve maternal and infant outcomes. This secondary analysis of 372 mother-infant dyads examines the associations of maternal body composition, as measured by BMI, fat mass and lean mass, with infant body composition, as measured by fat mass, lean mass, and BMI z-scores. Fat and lean masses were derived from dual-energy x-ray absorptiometry (DXA). Correlations between maternal BMI and maternal fat and lean mass were explored at one month postpartum. Associations between maternal body composition exposures at one month postpartum and infant body composition outcomes at one, four, and seven months postpartum were explored in the entire cohort and then stratified in two separate analyses by maternal BMI and infant sex to determine the potential for effect modification. Maternal BMI was strongly correlated with maternal fat mass at one month postpartum (r=0.91), and less strongly correlated with maternal lean mass (r=0.71). Maternal lean mass was positively associated with infant lean mass at four months postpartum. In obese women, maternal BMI was negatively associated with infant lean mass at seven months postpartum. In overweight women, maternal fat mass and maternal lean mass were positively associated with infant lean mass. In obese women, maternal fat mass was negatively associated with infant lean mass at four months postpartum. Maternal fat mass and lean mass were positively associated with infant lean mass at four and seven months postpartum in females but not in male infants. An increase in maternal lean mass was also found to be associated with a significant increase in female infant BMI z-scores at seven months postpartum but were not associated with male infants’ BMI z-scores. This study found that obese women with increased adiposity, as measured by BMI and fat mass, tended to have infants with less lean mass at four and seven months postpartum, while overweight women with increased lean mass tended to have infants with greater lean mass at all postpartum through seven months postpartum. It was also found that female infants born to mom’s with larger fat mass or larger lean mass tended to have increased lean mass at four and seven months postpartum, while there seemed to be no associations with maternal and infant body composition in male infants. These results confirm that the first year of life is an important time in infant development and potential programming, but they also suggest that this programming may be associated with lean mass accrual in early infancy as opposed to fat mass or adiposity. The complexity of the relationships between maternal and infant body composition in the postpartum period may involve other factors such as sex differences, genetics and nutrition, and should be further explored in future studies.

No description available.