Limb Muscular Strength and Bone Mineral Density in Elderly Subjects with Low Skeletal Muscle Mass Index.

The aim of the current study was to investigate the relationships between limb muscular strength and bone mineral density (BMD) in a group of elderly subjects with low skeletal muscle mass index (SMI).55 elderly Lebanese subjects (35 women and 20 men) participated in the current study. Handgrip, one-repetition maximum (1-RM) dumbbell curl (1-RM biceps), 1-RM lying one arm triceps (1-RM triceps), 1-RM calf raise, 1-RM leg extension and 1-RM leg curl were evaluated using validated methods.In both genders, 1-RM biceps, 1-RM triceps, 1-RM leg extension and 1-RM leg curl were positively correlated to total hip BMD. The current study shows that limb muscular strength is positively correlated to hip BMD in elderly subjects with low SMI. This may have clinical implications in the field of osteoporosis prevention in elderly subjects with low SMI.

Sarcopenia negatively affects hip structure analysis variables in a group of Lebanese postmenopausal women.

BACKGROUND: The current study's purpose is to compare hip structural analysis variables in a group of postmenopausal women with sarcopenia and another group of postmenopausal women with normal skeletal muscle mass index. To do so, the current study included 8 postmenopausal women (whose ages ranged between 65 and 84 years) with sarcopenia and 60 age-matched controls (with normal skeletal muscle mass index (SMI)). Body composition and bone parameters were evaluated by dual-energy X-ray absorptiometry (DXA). RESULTS: Weight, lean mass, body mass index, femoral neck cross-sectional area (FN CSA), FN section modulus (Z), FN cross sectional moment of inertia (CSMI), intertrochanteric (IT) CSA, IT Z, IT CSMI, IT cortical thickness (CT), femoral shaft (FS) CSA, FS Z and FS CSMI were significantly greater (p < 0.05) in women with normal SMI compared to women with sarcopenia. In the whole population, SMI was positively associated with IT CSA, IT Z, IT CSMI, IT CT, FS CSA, FS Z, FS CSMI, FS CT but negatively correlated to IT buckling ratio (BR) and FS BR. CONCLUSION: The current study suggests that sarcopenia has a negative effect on hip bone strength indices in postmenopausal women.

Muscular Maximal Strength Indices and Bone Variables in a Group of Elderly Women.

The aim of the present study was to explore the relations between muscular maximal strength indices and bone parameters (bone mineral density [BMD], hip geometry indices, and trabecular bone score [TBS]) in a group of elderly women. This study included 35 healthy elderly women whose ages range between 65 and 75 yr (68.1 ± 3.1 yr). BMD (in gram per square centimeter) was determined for each individual by dual-energy X-ray absorptiometry at the whole body, lumbar spine (L1-L4), total hip (TH), and femoral neck (FN). L1-L4 TBS and hip geometry indices were also evaluated by dual-energy X-ray absorptiometry. Maximal muscle strength of bench press (1-repetition maximum [RM] bench press), maximal muscle strength of leg press (1-RM leg press), and handgrip were measured using validated methods. 1-RM bench press was positively correlated to TH BMD (r = 0.40; p < 0.05), FN BMD (r = 0.41; p < 0.05), FN section modulus (r = 0.33; p < 0.05), and FN cross-sectional moment of inertia (r = 0.35; p < 0.05). 1-RM leg press was positively correlated to TH BMD (r = 0.50; p < 0.01), FN BMD (r = 0.35; p < 0.05), FN cross-sectional area (r = 0.38; p < 0.05), and TBS (r = 0.37; p < 0.05). Handgrip was correlated only to FN cross-sectional moment of inertia (r = 0.43; p < 0.01). This study suggests that 1-RM bench press and 1-RM leg press are positive determinants of BMD in elderly women.

Bone Geometric Properties of the Femoral Neck in Underweight Eumenorrheic Women.

The aim of this study was to describe femoral neck (FN) geometry among eumenorrheic underweight women around the age of peak bone mass. Proximal femur geometry and body composition were assessed in 12 underweight women and in 24 healthy controls using dual-energy X-ray absorptiometry. The Hip Structural Analysis program was used to determine bone geometry at the FN. The cross-sectional area (CSA) and the cross-sectional moment of inertia (CSMI) were significantly lower in underweight women than in controls (p < 0.05). There was a trend toward lower sectional modulus (Z) and strength index in underweight women (p < 0.15). Body weight, body mass index, and lean mass (LM) were positively correlated with CSA, CSMI, Z, and neck-shaft angle (r = 0.428-0.611, p < 0.05). After controlling for body weight, body mass index, and LM, the differences in CSA, CSMI, Z, and neck-shaft angle were no more statistically significant between the 2 groups. The multivariate analysis retained LM as the main predictor of CSA, CSMI, and Z in the whole population. The present study suggests that thinness is associated with low resistance to axial forces (CSA) and bending load (Z and CSMI) in adult eumenorrheic women. LM seems to be a key determinant of FN geometry in underweight women.

The relationships between bone variables and physical fitness across the BMI spectrum in young adult women.

In this cross-sectional study we aimed to evaluate the relationship between physical fitness and bone variables across the body mass index (BMI) spectrum in women aged 20-35 years. The study included 13 underweight women (BMI < 18.5 kg/m2), 24 normal weight women (BMI 18.5-24.9 kg/m2), and 20 overweight/obese women (BMI ≥ 25 kg/m2) aged between 20 and 35 years. Bone mineral density (BMD) and content (BMC) at the whole body, lumbar spine, and femoral neck, lumbar spine trabecular bone score, femoral neck geometry were assessed using dual-energy X-ray absorptiometry. Cardiorespiratory fitness and lower limb muscle power were estimated using the 20-m shuttle run test and the Sargent jump test, respectively. The associations between bone variables and physical fitness were different according to BMI categories. Correlations between physical fitness and bone parameters are particularly significant in normal BMI and less significant in low and high BMI. Multivariate ANCOVA regression models demonstrated that absolute VO2max (L/min) is a strong determinant of all the bone parameters regardless of BMI. Implementing strategies for increasing VO2max (L/min) by increasing lean mass and promoting resistance and/or high-intensity interval training could be effective to optimize bone health in underweight and overweight young adult women.

Positive Correlations Between Free Vitamin D and Bone Variables in a Group of Young Lebanese Women.

Optimizing bone mass in adulthood is of great importance to prevent the occurrence of osteoporosis in later age. Vitamin D is an essential component of bone health. Low-serum vitamin D is associated with low bone mineral density (BMD), which is an important predictor of fracture risk. However, most cells, apart from renal tubular cells, are exposed to free rather than to total 25-hydroxyvitamin D. Whether free vitamin D would be a better marker than total vitamin D is still under debate. The aim of the present study was to explore the relationships between serum total vitamin D, vitamin D-binding protein (BP), free vitamin D, and bone parameters in a group of young Lebanese women. This study included 88 young female adults aged between 18 and 35 yr. Body composition and BMD were assessed by dual-energy X-ray absorptiometry, and the lumbar spine trabecular bone score was derived. Bone mineral content (BMC) and BMD were measured at the whole body (WB), the lumbar spine (L1-L4), the total hip (TH), and the femoral neck (FN). To evaluate hip bone geometry, dual-energy X-ray absorptiometry scans were analyzed at the FN, the intertrochanteric region, and the femoral shaft by the Hip Structure Analysis program. The cross-sectional area, the index of axial compression strength, and the section modulus (Z), as well as index of bending strength, were measured from bone mass profiles. Composite indices of FN strength (compressive strength index [CSI], bending strength index, and impact strength index [ISI]) were calculated as previously described. Direct measurement of free 25-hydroxyvitamin D concentrations was performed by immunoassay, which detects free vitamin D by ELISA on a microtiter plate. Serum vitamin D BP was measured using a Quantikine ELISA kit, which employed the quantitative sandwich enzyme immunoassay technique. Serum free vitamin D was positively correlated with WB BMC (r = 0.26, p < 0.05), WB BMD (r = 0.29, p < 0.05), L1-L4 BMD (r = 0.28, p < 0.05), TH BMD (r = 0.34, p < 0.01), FN BMD (r = 0.29, p < 0.05), CSI (r = 0.24, p < 0.05), and ISI (r = 0.28, p < 0.05). No positive correlations were detected between the total vitamin D level, the vitamin D BPs, and BMD. The positive associations between free vitamin D and several bone variables (WB BMC, WB BMD, L1-L4 BMD, TH BMD, FN BMD, CSI, bending strength index, and ISI) remained significant after adjustment for weight. In conclusion, the current study suggests that the free vitamin D serum level is a stronger positive determinant of bone parameters and hip bone strength indices in young female adults than total serum vitamin D.

Evaluation of chronic kidney disease in cancer patients: is there a preferred estimation formula?

BACKGROUND: The evaluation of chronic kidney disease (CKD) in cancer patients seems to rely mostly on the Cockcroft-Gault (CG) formula or the creatinine levels to adjust treatment dosages which is a practice refuted by internists. AIMS: We evaluate the overall agreement of the CG, modification of diet in renal disease (MDRD) and CKD-epidemiology collaboration equations (CKD-EPI) equation with the newly devised Janowitz and Williams' (JW) equation. METHODS: The renal function was estimated in 235 cancer patients according to the CG, MDRD, body surface area (BSA)-adjusted MDRD, CKD-EPI, BSA-adjusted CKD-EPI and JW formulae. RESULTS: JW equation was more in agreement with CG and CKD-EPI estimations than the other equations. Taking JW equation as reference, receiver operating characteristic curve analysis showed that CG eGFR had the higher area under the curve when compared with other equations. Hierarchical cluster analysis showed more proximity between CG and JW equations than the other equations. CONCLUSION: The newly proposed JW eGFR estimation was more in agreement with CG equation than the other equations.

Vitamin D and Trabecular Bone Score in a Group of Young Lebanese Adults.

The relationship between vitamin D and trabecular bone score (TBS) in young adults remains unclear. The aim of this study was to explore the relationship between 25-hydroxyvitamin D [25(OH)D] serum levels and TBS in a healthy adult population. A total of 54 men and 61 women whose ages range from 18 to 35 participated in the present study. Participants with 25(OH)D insufficiency (between 21 and 29 ng/mL) were 55.7%, and those with 25(OH)D deficiency (≤20 ng/mL) were 11.4%. TBS positively correlated with 25(OH)D in men (r = 0.393; p <0.05) and women (r = 0.324; p < 0.05). In both genders, TBS was significantly higher in 25(OH)D-sufficient participants (≥30 ng/mL). The present study provides evidence that vitamin D positively affects bone health and suggests that maintaining adequate vitamin D status may be essential for optimal TBS values.

Increased Bone Marrow Adiposity in a Context of Energy Deficit: The Tip of the Iceberg?

Elevated bone marrow adiposity (BMA) is defined as an increase in the proportion of the bone marrow (BM) cavity volume occupied by adipocytes. This can be caused by an increase in the size and/or number of adipocytes. BMA increases with age in a bone-site-specific manner. This increase may be linked to certain pathophysiological situations. Osteoporosis or compromised bone quality is frequently associated with high BMA. The involvement of BM adipocytes in bone loss may be due to commitment of mesenchymal stem cells to the adipogenic pathway rather than the osteogenic pathway. However, adipocytes may also act on their microenvironment by secreting factors with harmful effects for the bone health. Here, we review evidence that in a context of energy deficit (such as anorexia nervosa (AN) and restriction rodent models) bone alterations can occur in the absence of an increase in BMA. In severe cases, bone alterations are even associated with gelatinous BM transformation. The relationship between BMA and energy deficit and the potential regulators of this adiposity in this context are also discussed. On the basis of clinical studies and preliminary results on animal model, we propose that competition between differentiation into osteoblasts and differentiation into adipocytes might trigger bone loss at least in moderate-to-severe AN and in some calorie restriction models. Finally, some of the main questions resulting from this hypothesis are discussed.