Osteoporosis: An Age-Related and Gender-Specific Disease – A Mini-Review

Osteoporosis, a classical age-related disease and known to be more common in women than in men, has been reported increasingly often in men during the past few years. Although men at all ages after puberty have larger bones than women, resulting in greater bending strength, mortality after a hip fracture, one of the major complications of osteoporosis, is more common in men than in women. Sex hormone deficiency is associated with unrestrained osteoclast activity and bone loss. Even though estrogen deficiency is more pronounced in women, it appears to be a major factor in the pathogenesis of osteoporosis in both genders. In contrast to osteoporosis in postmenopausal women, the treatment of osteoporosis in men has been scarcely reported. Nevertheless, some drugs commonly used for the treatment of osteoporosis in women also appear to be effective in men. The aim of this study is to review primary osteoporosis in the elderly with particular emphasis on gender-related aspects.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

Is weight loss harmful for skeletal health in obese older adults?

Purpose of Review: In view of the existing uncertainty about the implications of intentional weight loss in older obese adults, the present review (a) summarizes the available evidence from epidemiological and interventional studies concerning the effects of weight loss through lifestyle modifications on skeletal health parameters in older overweight/obese individuals, (b) proposes mechanisms that link weight loss to bone loss in this age group, and (c) identifies appropriate animal models. Main Findings and Future Directions: Based on prospective epidemiological studies, weight loss is associated with bone loss, impaired bone macro- and microstructure, and increased fracture risk in the elderly. Data from interventional studies confirm the negative effects of intentional weight loss achieved by lifestyle modifications on skeletal health outcomes in obese older individuals. These effects appear to be modest following a single weight loss attempt, but may persist in the longer term, and presumably, during subsequent weight loss efforts. Current evidence suggests that resistance exercise coupled with caloric restriction mitigates bone and muscle loss. However, alternative strategies do not exist for older individuals, especially those who are unable or unwilling to exercise. Clinical weight loss studies in obese older individuals and preclinical research in relevant animal models with obesity and osteoporosis are required. These will advance our understanding of the pathophysiology of weight-loss-associated skeletal alterations and provide evidence on how bone loss can be counteracted or prevented

Osteoporosis

Osteoporosis is a metabolic bone disease that, on a cellular level, results from osteoclastic bone resorption not compensated by osteoblastic bone formation. This causes bones to become weak and fragile, thus increasing the risk of fractures. Traditional pathophysiological concepts of osteoporosis focused on endocrine mechanisms such as estrogen or vitamin D deficiency as well as secondary hyperparathyroidism. However, research over the last decades provided exiting new insights into mechanisms contributing to the onset of osteoporosis, which go far beyond this. Selected mechanisms such as interactions between bone and the immune system, the gut microbiome, and cellular senescence are reviewed in this article. Furthermore, an overview on currently available osteoporosis medications including antiresorptive and bone forming drugs is provided and an outlook on potential future treatment options is given

The Power Spectrum of Mass Fluctuations Measured from the Lyman-alpha Forest at Redshift z=2.5

We measure the linear power spectrum of mass density fluctuations at redshift z=2.5 from the \lya forest absorption in a sample of 19 QSO spectra, using the method introduced by Croft et al. (1998). The P(k) measurement covers the range 2\pi/k ~ 450-2350 km/s (2-12 comoving \hmpc for \Omega=1). We examine a number of possible sources of systematic error and find none that are significant on these scales. In particular, we show that spatial variations in the UV background caused by the discreteness of the source population should have negligible effect on our P(k) measurement. We obtain consistent results from the high and low redshift halves of the data set and from an entirely independent sample of nine QSO spectra with mean redshift z=2.1. A power law fit to our measured P(k) yields a logarithmic slope n=-2.25 +/- 0.18 and an amplitude \Delta^2(k_p) = 0.57^{+0.26}_{-0.18}, where $\Delta^2$ is the contribution to the density variance from a unit interval of lnk and k_p=0.008 (km/s)^{-1}. Direct comparison of our mass P(k) to the measured clustering of Lyman Break Galaxies shows that they are a highly biased population, with a bias factor b~2-5. The slope of the linear P(k), never previously measured on these scales, is close to that predicted by models based on inflation and Cold Dark Matter (CDM). The P(k) amplitude is consistent with some scale-invariant, COBE-normalized CDM models (e.g., an open model with \Omega_0=0.4) and inconsistent with others (e.g., \Omega=1). Even with limited dynamic range and substantial statistical uncertainty, a measurement of P(k) that has no unknown ``bias factors'' offers many opportunities for testing theories of structure formation and constraining cosmological parameters. (Shortened)Comment: Submitted to ApJ, 27 emulateapj pages w/ 19 postscript fig

The effect of postexercise carbohydrate and protein ingestion on bone metabolism

Purpose To investigate the effect of feeding carbohydrate and protein (CHO+PRO), immediately or 2 h after an exhaustive run, on the bone turnover response in endurance runners. Methods 10 men (age 28±5 y, height 1.74±0.05 m, body mass 69.7±6.3 kg) performed treadmill running at 75%VO2max, until exhaustion, on three occasions. Blood was collected before and immediately, 1, 2, 3, 4 and 24 h post-exercise, for measurement of β-CTX, P1NP, PTH, PO4, ACa and Ca2+. This was a randomised, counterbalanced, placebo-controlled, single-blinded, cross-over study. The three trials were; i) placebo (PLA), PLA solution was ingested immediately and 2 h post-exercise, ii) immediate feeding (IF), CHO+PRO (1.5 g.kgBM-1 dextrose and 0.5 g.kgBM-1 whey) were ingested immediately post-exercise and PLA 2 h post-exercise, and iii) delayed feeding (DF), PLA was ingested immediately post-exercise and CHO+PRO solution 2 h post-exercise. Data were analysed using repeated measures ANOVA and post-hoc Tukey’s HSD. Results At 1 and 2 h post-exercise, β-CTX concentrations were lower in the IF trial than the DF and PLA trials (P≤0.001). At 3 h post-exercise, β-CTX concentrations were higher in the PLA trial than the IF (P≤0.001) and DF trials (P=0.026). At 4 h post-exercise, β-CTX concentrations were lower in the DF trial than the IF (P=0.003) and PLA trials (P≤0.001). At 4 h post-exercise, P1NP was higher in the IF trial than in DF (P=0.026) and PLA trials (P=0.001). At 3 h post-exercise, PTH was higher in the IF trial than the DF trial (P≤0.001). Conclusions Following exhaustive running, immediate ingestion of CHO+PRO may be beneficial, as it decreases bone resorption marker concentrations and increases bone formation marker concentrations; creating a more positive bone turnover balance

Analysis and modelling of muscles motion during whole body vibration

The aim of the study is to characterize the local muscles motion in individuals undergoing whole body mechanical stimulation. In this study we aim also to evaluate how subject positioning modifies vibration dumping, altering local mechanical stimulus. Vibrations were delivered to subjects by the use of a vibrating platform, while stimulation frequency was increased linearly from 15 to 60Hz. Two different subject postures were here analysed. Platform and muscles motion were monitored using tiny MEMS accelerometers; a contra lateral analysis was also presented. Muscle motion analysis revealed typical displacement trajectories: motion components were found not to be purely sinusoidal neither in phase to each other. Results also revealed a mechanical resonant-like behaviour at some muscles, similar to a second-order system response. Resonance frequencies and dumping factors depended on subject and his positioning. Proper mechanical stimulation can maximize muscle spindle solicitation, which may produce a more effective muscle activation

Physical activity and enhanced fitness to improve cognitive function in older people without known cognitive impairment

Background Physical activity is beneficial for healthy ageing. It may also help maintain good cognitive function in older age. Aerobic activity improves cardiovascular fitness, but it is not known whether this sort of fitness is necessary for improved cognitive function. Studies in which activity, fitness and cognition are reported in the same individuals could help to resolve this question. Objectives To assess the effectiveness of physical activity, aimed at improving cardiorespiratory fitness, on cognitive function in older people without known cognitive impairment. Search strategy We searched MEDLINE, EMBASE, PEDro, SPORTDiscus, PsycINFO, CINAHL, Cochrane Controlled Trials Register (CENTRAL), Dissertation abstracts international and ongoing trials registers on 15 December 2005 with no language restrictions. Selection criteria All published randomised controlled trials comparing aerobic physical activity programmes with any other intervention or no intervention with participants older than 55 years of age were eligible for inclusion. Data collection and analysis Eleven RCTs fulfilling the inclusion criteria are included in this review. Two reviewers independently extracted the data from these included studies. Main results Eight out of 11 studies reported that aerobic exercise interventions resulted in increased cardiorespiratory fitness of the intervention group (an improvement on the maximum oxygen uptake test which is considered to be the single best indicator of the cardiorespiratory system) of approximately 14% and this improvement coincided with improvements in cognitive capacity. The largest effects on cognitive function were found on motor function and auditory attention (effect sizes of 1.17 and 0.50 respectively). Moderate effects were observed for cognitive speed (speed at which information is processed; effect size 0.26) and visual attention (effect size 0.26). Authors' conclusions There is evidence that aerobic physical activities which improve cardiorespiratory fitness are beneficial for cognitive function in healthy older adults, with effects observed for motor function, cognitive speed, auditory and visual attention. However, the majority of comparisons yielded no significant results. The data are insufficient to show that the improvements in cognitive function which can be attributed to physical exercise are due to improvements in cardiovascular fitness, although the temporal association suggests that this might be the case. Larger studies are still required to confirm whether the aerobic training component is necessary, or whether the same can be achieved with any type of physical exercise. At the same time, it would be informative to understand why some cognitive functions seem to improve with (aerobic) physical exercise while other functions seem to be insensitive to physical exercise. Clinicians and scientists in the field of neuropsychology should seek mutual agreement on a smaller battery of cognitive tests to use, in order to render research on cognition clinically relevant and transparent and heighten the reproducibility of results for future research