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Body DXA (body + dxa)
Selected AbstractsBone Fragility Contributes to the Risk of Fracture in Children, Even After Moderate and Severe Trauma,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2008Emma M Clark Abstract We prospectively examined whether the relationship between skeletal fragility and fracture risk in children 9.9 ± 0.3 (SD) yr is affected by trauma level. Bone size relative to body size and humeral vBMD showed similar inverse relationships with fracture risk, irrespective of whether fractures followed slight or moderate/severe trauma. Introduction: Fracture risk in childhood is related to underlying skeletal fragility. However, whether this relationship is confined to low-trauma fractures or whether skeletal fragility also contributes to the risk of fracture caused by higher levels of trauma is currently unknown. Materials and Methods: Total body DXA scan results obtained at 9.9 yr of age were linked to reported fractures over the following 2 yr in children from the Avon Longitudinal Study of Parents and Children. DXA scan results that were subsequently derived included total body less head (TBLH) bone size relative to body size (calculated from TBLH area adjusted for height and weight) and humeral volumetric BMD (vBMD; derived from subregional analysis at this site). Trauma level was assigned using the Landin classification based on a questionnaire asking about precipitating causes. Results: Of the 6204 children with available data, 549 (8.9%) reported at least one fracture over the follow-up period, and trauma level was assigned in 280 as follows: slight trauma, 56.1%; moderate trauma, 41.0%; severe trauma, 2.9%. Compared with children without fractures, after adjustment for age, sex, socioeconomic status, and ethnicity, children with fractures from both slight and moderate/severe trauma had a reduced bone size relative to body size (1133 cm2 in nonfractured children versus 1112 cm2 for slight trauma fractures, p < 0.001; 1112 cm2 for moderate/severe trauma fractures, p = 0.001) and reduced humeral vBMD (0.494 g/cm3 in nonfractured children versus 0.484 g/cm3 for slight trauma fractures, p = 0.036; and 0.482g/cm3 for moderate/severe trauma fractures, p = 0.016). Conclusions: Skeletal fragility contributes to fracture risk in children, not only in fractures caused by slight trauma but also in those that result from moderate or severe trauma. [source] Habitual Levels of Physical Activity Influence Bone Mass in 11-Year-Old Children From the United Kingdom: Findings From a Large Population-Based Cohort,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2007Jon H Tobias MD Abstract We examined the influence of habitual levels of physical activity on bone mass in childhood by studying the relationship between accelerometer recordings and DXA parameters in 4457 11-year-old children. Physical activity was positively related to both BMD and bone size in fully adjusted models. However, further exploration revealed that this effect on bone size was modified by fat mass. Introduction: Exercise interventions have been reported to increase bone mass in children, but it is unclear whether levels of habitual physical activity also influence skeletal development. Materials and Methods: We used multivariable linear regression to analyze associations between amount of moderate and vigorous physical activity (MVPA), derived from accelerometer recordings for a minimum of 3 days, and parameters obtained from total body DXA scans in 4457 11-year-old boys and girls from the Avon Longitudinal Study of Parents and Children. The influence of different activity intensities was also studied by stratification based on lower and higher accelerometer cut-points for moderate (3600 counts/minute) and vigorous (6200 counts/minute) activity, respectively. Results: MVPA was positively associated with lower limb BMD and BMC adjusted for bone area (aBMC; p < 0.001, adjusted for age, sex, socio-economic factors, and height, with or without additional adjustment for lean and fat mass). MVPA was inversely related to lower limb bone area after adjusting for height and lean mass (p = 0.01), whereas a positive association was observed when fat mass was also adjusted for (p < 0.001). Lower limb BMC was positively related to MVPA after adjusting for height and lean and fat mass (p < 0.001), whereas little relationship was observed after adjusting for height and lean mass alone (p = 0.1). On multivariable regression analysis using the fully adjusted model, moderate activity exerted a stronger influence on lower limb BMC compared with light activity (light activity: 2.9 [1.2,4.7, p = 0.001]; moderate activity: 13.1 [10.6,15.5, p < 0.001]; regression coefficients with 95% confidence intervals and p values). Conclusions: Habitual levels of physical activity in 11-year-old children are related to bone size and BMD, with moderate activity exerting the strongest influence. The effect on bone size (as reflected by DXA-based measures of bone area) was modified by adjustment for fat mass, such that decreased fat mass, which is associated with higher levels of physical activity, acts to reduce bone size and thereby counteract the tendency for physical activity to increase bone mass. [source] Total body bone measurements: A cross-sectional study in children with acute lymphoblastic leukemia during and following completion of therapyPEDIATRIC BLOOD & CANCER, Issue 1 2009Kara M. Kelly MD Abstract Background Abnormalities in bone mineral density (BMD) occur in children treated for acute lymphoblastic leukemia (ALL). However, BMD estimates have been performed using varied instruments, reference data, and interpretations. This exploratory cross sectional study to evaluate bone mass in children with ALL, uses an algorithm that serially adjusts for variables known to affect pediatric bone measures by dual energy X-ray absorptiometry (DXA), based on models developed in 1,218 healthy children and adolescents. Procedure Anthropometry, DXA scans, and factors with possible influence on bone mass were evaluated in 21 ALL patients receiving chemotherapy and 20 in the follow-up phase. Main outcome was treatment group differences in Z -scores for total body bone mineral content (BMC), bone area (Area), and areal BMD (aBMD). Results Mean Z -scores for the entire study population for BMC, Area, and aBMD were significantly less than zero. Among possible contributing factors, only calcium intake was a significant co-variate. Comparison between treatment groups showed that least-square mean Z -scores for patients on-therapy for at least 12 months were significantly lower than those off therapy for at least 12 months (P: 0.0008,0.044), except for BMC at last step of the algorithm (adjusted for sex, age, ethnicity, height, weight, and bone area). Conclusions Evaluation of total body DXA by this algorithm is consistent with better general bone status in those off-therapy. However, in this small exploratory study, the lack of significant difference between Z -scores for fully adjusted BMC in on- versus off-therapy groups suggests possible risk of low peak bone mass. Additional longitudinal evaluation is warranted. Pediatr Blood Cancer 2009;52:33,38. © 2008 Wiley-Liss, Inc. [source] No association between inhaled corticosteroids and whole body DXA in postmenopausal women,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 7 2006Sölve Elmståhl MD Abstract Purpose Postmenopausal women treated with corticosteroids are regarded as a high-risk group due to the effect of both natural bone loss and possible adverse effects of treatment with inhaled corticosteroids (IC). Objective To compare bone mineral density (BMD) in postmenopausal women exposed only to IC (IC group, n,=,106) with that of BMD in women not exposed to corticosteroids (n,=,124) and women exposed to oral and/or intra-articular injections in addition to inhaled corticosteroids (OC group, n,=,31). The women were recruited from a population-based prospective cohort study. Methods Dual X-ray absorptiometry (DXA) technique was used to measure BMD in whole body, spine, pelvis and lower extremities. A health questionnaire and an interview about past and present medication use were used. Results The mean duration and dose of IC were 9.5,±,4.5 years and 615,µg daily. Whole body BMD did not significantly differ between the IC group (1.103,g/cm2) and the unexposed group (1.087,g/cm2). Within the IC group, BMD stratified for cumulative dose of IC, duration or current dose above or below 800,µg did not differ. Z -score BMD for tertiles did not differ when comparing the IC and OC groups. Conclusion No difference in BMD was noted between postmenopausal women exposed to inhaled corticosteroids and unexposed controls nor was there any dose response relationship between inhaled corticosteroid therapy and BMD. Copyright © 2006 John Wiley & Sons, Ltd. [source] |