Dataset Information

Bone loss in elderly men: increased endosteal bone loss and stable periosteal apposition. The prospective MINOS study.

ABSTRACT: INTRODUCTION: Longitudinal studies on the age-related bone loss in men concerns the decrease in areal bone mineral density (aBMD), which can be qualified as "apparent bone loss" because it does not reflect the change in bone mineral content (BMC). Loss of BMC can be referred to as "net bone loss" because it does not take into account the morphological basis of the bone loss (decreased periosteal apposition; endosteal bone loss, i.e. bone loss on the trabecular, endocortical and intracortical surfaces). The aim of this study was to assess age-related apparent net and endosteal bone loss as well as their morphological basis and age-related changes during a prospective follow-up in a large cohort of elderly men. METHODS: This analysis was performed in 725 men aged 51-85 at baseline who were followed up for 90 months. RESULTS: Bone densitometry was carried out at the lumbar spine, hip and whole body by using the HOLOGIC QDR1500 device and at the distal forearm by using the Osteometer DTX100 device. Sixty-five men who abandoned the study after the first examination were older and had lower aBMC at most sites of measurement. Apparent bone loss was significant at the hip, distal forearm and whole body. Net bone loss was also significant at these sites, except for the femoral neck. Periosteal expansion was significant at all sites of measurement. Apparent and net bone loss accelerated with age, whereas the rate of periosteal expansion remained stable. At the distal radius and ulna, endosteal bone loss accelerated with age, whereas the rate of periosteal apposition remained stable. CONCLUSION: In a large cohort of elderly men, age-related apparent bone loss (aBMD) at the hip, distal forearm and whole body was determined by the net bone loss (BMC), except for the femoral neck. Apparent and net bone loss accelerated with age, whereas the periosteal expansion rate (bone widening) remained constant. At the distal forearm, age-related acceleration of the apparent bone loss was determined by the higher endosteal bone loss, whereas the periosteal apposition rate (estimated mass of deposited bone) remained constant.

SUBMITTER: Szulc P

PROVIDER: S-EPMC1820756 | biostudies-other | 2007 Apr

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:The capacity of bone to optimize its structure in response to mechanical loads has been widely observed. The mechanical load acting on a bone at the macroscopic level influences the bone cells, particularly osteocytes within the lacunae canalicular network (LCN). Osteocytes are responsive to a range of physical signals, including strain, interstitial fluid flow, and pore pressure. However, physiological tissue strain is known to be typically smaller than that required to directly induce bone formation. On the other hand, as per evidence provided by this study from the literature, models based on fluid flow alone cannot simultaneously predict bone formation at both the periosteal and endocortical surfaces. This suggests that another component of the osteocyte's mechanical environment, such as pore pressure, may play an essential role in bone adaptation, either alone or in combination with other stimuli, such as tissue strain and/or interstitial fluid flow. In vitro experiments have also confirmed that osteocytes respond to cyclic pore pressure and, thus, have a mechanism to sense the pressure, possibly because of its viscoelasticity. In this work, dissipation energy density, being irreversible work done per unit volume, has been successfully used as a greater stimulus to incorporate all of the parameters of mechanical environments of the LCN, such as waveforms of both fluid velocity and pore pressure, number of loading cycles. Mineral Apposition Rate (MAR) has also been mathematically derived to be proportional to the square root of the dissipation energy density minus its reference value. A hypothesis is accordingly proposed and successfully tested/validated for both endocortical and periosteal surfaces with respect to an in-vivo study on mouse tibia available in the literature. The constant of proportionality and the reference/threshold value of the dissipation energy density are determined through a nonlinear curve fitting. The mathematical/computational method thus developed is then successfully used to predict MAR at both endocortical and periosteal surfaces induced by a different loading condition. Computational implementation of the mathematical model has been done through a poroelastic finite element analysis of bone, where bone is assumed to be porous and filled with fluid, with a boundary condition that the periosteum is impermeable to the fluid and the endosteal surface maintains a reference zero pressure. This work also provides evidence for these assumptions to be true based on the state-of-the-art literature on related experimental studies. The currently developed model shows that the bone uses these conditions (assumptions) to its advantage, as the greater stimulus, i.e., the dissipation energy due to both fluid flow and pore pressure, are of a similar order at both the surfaces, and hence osteogenesis of the same order at both the surfaces. As a bottom line, the resulting model is the first of its kind as it has been able to correctly predict MAR at both endocortical and periosteal surfaces. This study thus significantly advances the modeling of cortical bone adaptation to exogenous mechanical loading.

Project description:One risk factor for osteoporosis that has attracted increasing attention in recent years is exposure to cadmium. The aim of this study was to examine the associations between low-level cadmium exposure, from diet and smoking, and bone mineral density (BMD) and incident fractures in elderly men. The study population consisted of 936 men from the Swedish cohort of the Osteoporotic Fractures in Men (MrOS) study, aged 70 to 81 years at inclusion (years 2002 to 2004), with reliable data on cadmium in urine (U-Cd) analyzed using inductively coupled plasma mass spectrometry in baseline samples. The participants also answered a questionnaire on lifestyle factors and medical history. BMD was measured at baseline using dual-energy X-ray absorptiometry (DXA) in the total body, hip, and lumbar spine. During the follow-up period (until 2013), all new fractures were registered by date and type. Associations between BMD and U-Cd were assessed using multiple linear regression, and associations between incident fractures and baseline U-Cd were analyzed using Cox regression. In both cases, a number of potential confounders and other risk factors (eg, age, smoking, body mass index [BMI], and physical activity) were included in the models. We found significant negative associations between U-Cd and BMD, with lower BMD (4% to 8%) for all sites in the fourth quartile of U-Cd, using the first quartile as the reference. In addition, we found positive associations between U-Cd and incident fractures, especially nonvertebral osteoporosis fractures in the fourth quartile of U-Cd, with hazard ratios of 1.8 to 3.3 in the various models. U-Cd as a continuous variable was significantly associated with nonvertebral osteoporosis fractures (adjusted hazard ratio 1.3 to 1.4 per μg Cd/g creatinine), also in never-smokers, but not with the other fracture groups (all fractures, hip fractures, vertebral fractures, and other fractures). Our results indicate that even relatively low cadmium exposure through diet and smoking increases the risk of low BMD and osteoporosis-related fractures in elderly men.

Project description:Prior studies suggest that increased urine albumin is associated with a heightened fracture risk in women, but results in men are unclear. We used data from Osteoporotic Fractures in Men (MrOS), a prospective cohort study of community-dwelling men aged ≥65 years, to evaluate the association of increased urine albumin with subsequent fractures and annualized rate of hip bone loss. We calculated albumin/creatinine ratio (ACR) from urine collected at the 2003-2005 visit. Subsequent clinical fractures were ascertained from triannual questionnaires and centrally adjudicated by review of radiographic reports. Total hip BMD was measured by DXA at the 2003-2005 visit and again an average of 3.5 years later. We estimated risk of incident clinical fracture using Cox proportional hazards models, and annualized BMD change using ANCOVA. Of 2982 men with calculable ACR, 9.4% had ACR ≥30 mg/g (albuminuria) and 1.0% had ACR ≥300 mg/g (macroalbuminuria). During a mean of 8.7 years of follow-up, 20.0% of men had an incident clinical fracture. In multivariate-adjusted models, neither higher ACR quintile (p for trend 0.75) nor albuminuria (HR versus no albuminuria, 0.89; 95% CI, 0.65 to 1.20) was associated with increased risk of incident clinical fracture. Increased urine albumin had a borderline significant, multivariate-adjusted, positive association with rate of total hip bone loss when modeled in ACR quintiles (p = 0.06), but not when modeled as albuminuria versus no albuminuria. Macroalbuminuria was associated with a higher rate of annualized hip bone loss compared to no albuminuria (-1.8% more annualized loss than in men with ACR <30 mg/g; p < 0.001), but the limited prevalence of macroalbuminuria precluded reliable estimates of its fracture associations. In these community-dwelling older men, we found no association between urine albumin levels and risk of incident clinical fracture, but found a borderline significant, positive association with rate of hip bone loss. © 2016 American Society for Bone and Mineral Research.

Dataset Information

Bone loss in elderly men: increased endosteal bone loss and stable periosteal apposition. The prospective MINOS study.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets