Search results for "Bone density"
showing 10 items of 339 documents
In vivo vibrational wave propagation in human tibiae at different ages
1989
Vibrational wave propagation was tested in vivo on the tibial bone of both legs of 56 female volunteers. The impact was produced by a hammer with a force strain gauge and the response was monitored by two accelerometers. The peak amplitude of the accelerations, the velocity of the acceleration wave propagation and damping were analysed for comparison among the different age groups. The results showed significant negative correlations between age and the peak amplitude of acceleration, and the velocity of acceleration wave propagation (p less than 0.01). The damping time of the acceleration wave also had a negative correlation with age. These findings suggested that age differences were rela…
The effects of calorie restriction, intermittent fasting and vegetarian diets on bone health.
2019
Uncountable health care organizations, clinicians, and individuals are striving to prevent obesity and the many chronic medical conditions linked to it by advocating a healthy lifestyle that includes measures such as reducing dietary calorie intake (i.e., calorie restriction = CR and intermittent fasting = IF) or limiting/abolishing animal source foods (i.e., practices termed vegetarianism and veganism). Although these regimens are traditionally considered healthy, their real impact on bone health has yet to be established, and some studies have reported that they have negative effects on bone outcomes. The current work provides an overview of the studies carried out to examine the effect/s…
25-hydroxy vitamin D levels in healthy premenopausal women: Association with bone turnover markers and bone mineral density
2008
Abstract Background Vitamin D deficiency is very common in elderly people while there are very few reports on its incidence, determinants and metabolic consequences in young subjects. Results In 608 young healthy premenopausal women participating in the BONTURNO study, levels of 25-hydroxyvitamin D [25(OH)D] below 20 ng/ml were found in almost a third of the women. Its levels were inversely ( P 2 ) and directly with sunlight exposure during the summer time, and latitude: i.e. the higher the latitude over Italy, the higher the 25(OH)D level. In women on contraceptive pill the mean 25(OH)D level was significantly increased even when the data were adjusted for age, BMI and sun exposure. 25(OH)…
Exercise loading and cortical bone distribution at the tibial shaft
2011
Cortical bone is not a uniform tissue, and its apparent density [cortical volumetric density (vBMD)] varies around the bone cross-section as well as along the axial length of the bone. It is not yet known, whether the varying vBMD distribution is attributable to modulation in the predominant loads affecting bone. The aim of the present study was to compare the cortical bone mass distribution through the bone cortex (radial distribution) and around the center of mass (polar distribution) among 221 premenopausal women aged 17-40 years representing athletes involved in high impact, odd impact, high magnitude, repetitive low impact, repetitive non-impact sports and leisure time physical activit…
Is bone loss the reversal of bone accrual? Evidence from a cross-sectional study in daughter-mother-grandmother trios.
2011
Bone adapts to mechanical loads applied on it. During aging, loads decrease to a greater extent at those skeletal sites where loads increase most in earlier life. Thus, the loss of bone may occur preferentially at sites where most bone has been deposited previously; ie, bone loss could be the directional reversal of accrual. To test this hypothesis, we compared the bone mass distribution at weight-bearing (tibia) and non-weight-bearing (radius) bones among 18-year-old girls, their premenopausal mothers, and their postmenopausal maternal grandmothers. Bone and muscle properties were measured by pQCT, and polar distribution of bone mass was obtained in 55 girl-mother–maternal grandmother trio…
Incidence of bisphosphonate-associated osteonecrosis of the jaws in breast cancer patients.
2009
BACKGROUND: Bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) is a relatively new disease. The aim of this study was to evaluate the prevalence of BP-ONJ in breast cancer patients with osseous metastasis and bisphosphonate therapy. METHODS: A retrospective study was conducted in a EUSOMA accredited breast unit in Germany. All patients treated from January of 2000 to March of 2006 with metastatic breast cancer and bisphosphonate therapy were reviewed. All patients were contacted, and missing data were completed through structured interviews with their dentists and physicians (n = 75). Primary outcome was the development of BP-ONJ and the detection of possible additional trigger fa…
Effect of undersized drilling on the stability of immediate tapered implants in the anterior maxillary sector. A randomized clinical trial.
2020
Background To evaluate the effect of undersized drilling on the primary and secondary stability of immediate implants placed in the anterior maxilla. Material and Methods A comparative randomized clinical trial was carried out in 30 healthy adults. Thirty tapered implants, 16 involving conventional drilling and 14 undersized drilling, were placed immediately after anterior maxillary tooth removal. Insertion torque and implant stability assessed by resonance frequency analysis (RFA) were evaluated at three different timepoints: at implant placement and 6 and 12 weeks post-implantation. The results were compared using parametric statistical tests. Results All implants showed adequate stabilit…
Long-term leisure time physical activity and properties of bone: A twin study
2009
Effects of physical activity on bone properties, when controlled for genetic effects, are not fully understood. We aimed to study the association between long-term leisure time physical activity (LTPA) and bone properties using twin pairs known to be discordant for leisure time physical activity for at least 30 yr. Volumetric BMD and geometric properties were measured at the tibia shaft and distal end using pQCT in 16 middle-aged (50-74 yr) same-sex twin pairs (seven monozygotic [MZ] and nine dizygotic [DZ] pairs) selected from a population-based cohort. Paired differences between active and inactive co-twins were studied. Active members of MZ twin pairs had larger cortical bone cross-secti…
Loading modalities and bone structures at nonweight-bearing upper extremity and weight-bearing lower extremity: a pQCT study of adult female athletes.
2005
This cross-sectional study of adult female athletes assessed whether the apparent loading-related differences in bone structure are primarily associated with the loading type or the muscle performance-related joint moments. Several structural variables at shaft sites of the tibia, radius and humerus, and distal sites of the tibia and radius were measured with peripheral quantitative computed tomography (pQCT) among 113 female national level athletes (representing hurdling, volleyball, soccer, racket-sports and swimming) and their 30 nonathletic referents. For the weight-bearing lower extremities, the loading modalities of the above sports were classified into high-impact (hurdling, volleyba…
Association between long-term exercise loading and lumbar spine trabecular bone score (TBS) in different exercise loading groups
2015
Objective: To examine whether different exercise loading is associated with lumbar vertebral texture as assessed with Trabecular Bone Score (TBS). Methods: Data from 88 Finnish female athletes and 19 habitually active women (reference group) were analyzed. Participants’mean age was 24.3 years(range 17-40 years).Athletes were divided into five specific exercise loading groups according to sport-specific training history: high-impact (triple jumpers and high jumpers), odd-impact (soccer players and squash players), high-magnitude (power lifters), repetitive impact (endurance runners), and repetitive non-impact (swimmers). TBS-values were determined from lumbar vertebral L1-L4 DXA images. Body…