Maximal oxygen consumption and bone mineral density in a group of young Lebanese adults

The Benefits of Utilizing Total Body Composition as a Predictor of Cardiorespiratory Fitness Based on Age: A Pilot Study

Maximal oxygen consumption (VO2max) has been associated with body fat percentage (%BF) or fat free mass. However, most analyses do not consider total body composition (TBC) as defined by %BF, fat free mass index (FFMI—a height-adjusted measure of muscle mass), visceral adipose tissue, and bone mineral content (BMC). The aim of this study was to determine if TBC predicts cardiorespiratory fitness in healthy adults and if a relationship exists in young and older adults. Sixty healthy individuals (age group 1 (AG1, ≤35 years), n = 35; age group 2 (AG2, >35 years), n = 25) were screened in a cross-sectional study and retrospectively examined. All participants completed a full body DEXA scan and a standardized multistage treadmill test to determine VO2max. A multiple linear regression analysis was performed to examine the relationship between TBC and VO2max. The multiple regression model showed an overall significant effect for TBC (p < 0.001, R2 = 0.282). When analyzed by age group, the regression model of TBC was not significant in young adults (AG1, p = 0.319, R2 = 0.141), but significant in older adults (AG2, p < 0.001, R2 = 0.683). Significant predictors of VO2max in the older cohort were %BF (β = −0.748, p = 0.001) and BMC (β = 0.014, p = 0.002). Total body composition predicted VO2max in a small cohort of healthy adults. This study highlights the importance of TBC for cardiovascular health, especially in mid-to later-life individuals.

Composite Indices of Femoral Neck Strength in Middle-Aged Inactive Subjects Vs Former Football Players

The purpose of this study was to compare composite indices of femoral neck strength ((compression strength index [CSI], bending strength index [BSI], and impact strength index [ISI]) in inactive middle-aged men (n = 20) and middle-aged former football players (n = 15). 35 middle-aged men participated in this study. Body composition and bone variables were evaluated by dual-energy X-ray absorptiometry. Composite indices of femoral neck strength (CSI, BSI, and ISI) were calculated. Handgrip strength, vertical jump, maximum power of the lower limbs (watts), horizontal jump, maximal half-squat strength, maximal bench-press strength, sprint performance (10 meters), and maximum oxygen consumption (VO₂ max, ml/min/kg) were evaluated using validated tests. CSI, BSI, and ISI were significantly higher in football players compared to inactive men. Vertical jump, horizontal jump, maximal half-squat strength, VO₂ max and sprint performance were significantly different between the 2 groups. CSI, BSI, and ISI remained significantly higher in football players compared to inactive men after adjusting for physical activity level. The current study suggests that former football practice is associated with higher composite indices of femoral neck strength in middle-aged men.

The Relationships Between Skeletal Muscle Index and Bone Variables in a Group of Young Adults

The purpose of this study was to investigate the relationships between skeletal muscle index (SMI) and bone variables in a group of young adults. Three hundred and thirty-five young adults (129 men and 206 women) whose ages ranged from 18 to 35 yr voluntarily participated in this study. Weight and height were measured, and body mass index (BMI) was calculated. Body composition, bone mineral content (BMC), bone mineral density (BMD), geometric indices of hip bone strength and trabecular bone score (TBS) were determined for each individual by Dual-energy X-ray absorptiometry (DXA). Appendicular skeletal mass (ASM, in kg) was calculated by summing the muscle masses of the 4 limbs, assuming that all nonfat and nonebone mass is skeletal muscle. Skeletal muscle index (SMI) was defined as ASM/height². In young men, SMI was positively correlated to WB BMC (r = 0.63; p < 0.001), WB BMD (r = 0.53; p < 0.001), L1-L4 BMC (r = 0.33; p < 0.001), L1-L4 BMD (r = 0.30; p < 0.001), L1-L4 TBS (r = 0.26; p < 0.01), TH BMC (r = 0.61; p < 0.001), TH BMD (r = 0.46; p < 0.001), FN BMC (r = 0.51; p < 0.001), FN BMD (r = 0.46; p < 0.001), FN cross-sectional area (CSA) (r = 0.56; p < 0.001), FN cross-sectional moment of inertia (CSMI) (r = 0.52; p < 0.001) and FN section modulus (Z) (r = 0.54; p < 0.001) but negatively correlated to FN strength index (SI) (r = -0.24; p < 0.01). In young women, SMI was positively correlated to WB BMC (r = 0.61; p < 0.001), WB BMD (r = 0.60; p < 0.001), L1-L4 BMC (r = 0.35; p < 0.001), L1-L4 BMD (r = 0.33; p < 0.001), L1-L4 TBS (r = 0.29; p < 0.001), TH BMC (r = 0.61; p < 0.001), TH BMD (r = 0.53; p < 0.001), FN BMC (r = 0.45; p < 0.001), FN BMD (r = 0.49; p < 0.001), FN CSA (r = 0.60; p < 0.001), FN CSMI (r = 0.52; p < 0.001), and FN Z (r = 0.40; p < 0.001) but negatively correlated to FN SI (r = -0.20; p < 0.01). The current study suggests that SMI is a positive determinant of bone mineral density and geometric indices of hip bone strength in young adults.

Influence of Physical Activity Level on Composite Indices of Femoral Neck Strength in a Group of Young Overweight Men

The aim of the present study was to explore the influence of physical activity level on composite indices of femoral neck strength (compression strength index [CSI], bending strength index, and impact strength index) in a group of young overweight men. To do so, we compared composite indices of femoral neck strength in active overweight men and insufficiently active overweight men. They were divided into 2 groups based on their physical activity level: 70 active overweight men (engaging in more than 150 minutes of physical activity per week; 8.7 ± 4.8 h/wk) and 26 insufficiently active overweight men (engaging in less than 150 minutes of physical activity per week; 1.2 ± 0.7 h/wk). Height (m) and weight (kg) were measured, and body mass index (kg/m²) was calculated. Bone mineral density was measured by dual-energy X-ray absorptiometry at whole body, lumbar spine, total hip, and femoral neck. Body weight, lean mass, fat mass, and body mass index were not significantly different between the 2 groups. CSI, bending strength index, and impact strength index were significantly higher in active overweight men compared to insufficiently active overweight men. After adjustment for age, physical activity (h/wk) and lean mass, only CSI remained higher in active overweight men compared to insufficiently active overweight men. This study suggests that, in young overweight men, being active (engaging in more than 150 minutes of physical activity per week) is associated with greater composite indices of femoral neck strength. To our knowledge, this is the first study that finds a significant difference regarding composite indices of femoral neck strength between 2 groups of young overweight men with different levels of physical activity.

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.

Does Muscular Power Predict Bone Mineral Density in Young Adults?

The aim of this study was to explore the relationships between maximum power and bone variables in a group of young adults. Two hundred and one young adults (53 men and 148 women) whose ages range from 18 to 35 years voluntarily participated in this study. Weight and height were measured, and body mass index was calculated. Body composition, bone mineral content (BMC) and bone mineral density (BMD) were determined for each individual by dual-energy X-ray absorptiometry. Vertical jump was evaluated using a validated field test (Sargent test). The highest vertical jump was selected. Maximum power (P max, in watts) of the lower limbs was calculated accordingly. In young men, maximum power was positively correlated to whole body (WB) BMC (r = 0.65; p < 0.001), WB BMD (r = 0.41; p < 0.01), L1-L4 BMC (r = 0.54; p < 0.001), total hip (TH) BMC (r = 0.50; p < 0.001), femoral neck (FN) BMC (r = 0.35; p < 0.01), FN cross-sectional area (CSA) (r = 0.33; p < 0.05) and FN cross-sectional moment of inertia (CSMI) (r = 0.50; p < 0.001). In young women, maximum power was positively correlated to WB BMC (r = 0.48; p < 0.001), WB BMD (r = 0.28; p < 0.001), L1-L4 BMC (r = 0.34; p < 0.001), TH BMC (r = 0.43; p < 0.001), TH BMD (r = 0.21; p < 0.01), FN BMC (r = 0.42; p < 0.001), FN BMD (r = 0.31; p < 0.001), FN CSA (r = 0.41; p < 0.001), FN CSMI (r = 0.40; p < 0.001) and FN Z (r = 0.41; p < 0.01). The current study suggests that maximum power is a positive determinant of WB BMC, WB BMD, FN CSA, and FN CSMI in young men. It also shows that maximum power is a positive determinant of WB BMC, WB BMD, TH BMD, FN BMD, FN CSA, FN CSMI, and FN Z in young 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 VO_2max (L/min) is a strong determinant of all the bone parameters regardless of BMI. Implementing strategies for increasing VO_2max (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.

Physical Performance Variables and Bone Parameters in a Group of Young Overweight and Obese Women

The aim of this study was to explore the relationships between physical performance variables and bone parameters such as bone mineral density (BMD), bone mineral content, hip geometry indices, and trabecular bone score in a group of young overweight and obese adult women. Sixty-eight overweight/obese (body mass index ≥25 kg/m²; 25.5-42.4 kg/m²) young women whose ages range from 18 to 35 yr participated in this study. Body composition and bone outcomes were measured by dual-energy X-ray absorptiometry. Maximum oxygen consumption (VO₂ max, in liter per minute) was determined indirectly using a progressive shuttle run test. One-repetition-maximum half-squat was directly measured. Vertical jump was measured and maximum power (P max) of the lower limbs was calculated. Lean mass was positively correlated to whole body (WB) BMD, total hip BMD, femoral neck (FN) BMD, femoral neck cross-sectional area (FN CSA) and femoral neck cross sectional moment of inertia (FN CSMI) (p < 0.05). VO₂ max (in liter per minute) and muscle power were positively correlated to WB BMD, total hip BMD, FN BMD, FN CSA, and FN CSMI (p < 0.05). One-repetition-maximum half-squat was positively correlated with lumbar spine trabecular bone score, WB BMD, FN BMD, FN CSA and FN CSMI (p < 0.05). This study suggests that lean mass, vertical jump, VO₂ max (liter per minute), muscle power and one-repetition-maximum half squat are positive determinants of BMD and hip geometry indices in young overweight and obese women.

Physical Performance Variables and Bone Mineral Density in a Group of Young Overweight and Obese Men

The aim of this study was to explore the relationships between performances obtained in different physical tests and bone parameters (bone mineral density [BMD], bone mineral content, hip geometry indices, and trabecular bone score [TBS]) in a group of young Lebanese overweight and obese adult men. Fifty-two overweight and/or obese (body mass index > 25 kg/m²) young men whose ages range from 18 to 35 yr participated in this study. Weight and height were measured, and body mass index was calculated. Body composition, BMD, cross-sectional area and section modulus (Z) of the femoral neck (FN), and TBS were measured by dual-energy X-ray absorptiometry. Maximum oxygen consumption (VO₂ max, in liter per minute) was determined by direct measurement while exercising on a medical treadmill. One-repetition-maximum half-squat and maximum power (P max) of the lower limbs were measured using validated exercises. Lean mass was a positive determinant of whole-body bone mineral content (r = 0.71, p < 0.001), FN cross-sectional area (r = 0.51, p < 0.001), and FN Z (r = 0.58, p < 0.001). VO₂ max (in liter per minute) was a positive determinant of whole-body BMD (r = 0.47, p < 0.001), total hip BMD (r = 0.43, p < 0.01), and FN BMD (r = 0.42, p < 0.01). VO₂ max (in milliliter per minute per kilogram) was a positive determinant of TBS (r = 0.30, p < 0.05). One repetition maximum was a positive determinant of L1-L4 BMD (r = 0.33, p < 0.05). This study suggests that VO₂ max (in liter per minute) is a positive determinant of BMD, and VO₂ max (in milliliter per minute per kilogram) is a positive determinant of TBS in overweight and obese men.

Sport- and sample-specific features of trace elements in adolescent female field hockey players and fencers

Active physical exercises and growth are associated with mineral imbalances in young athletes. The purpose of this study was to examine the impact of sport-related factors on tissue mineral status in adolescent female athletes. Saliva and hair samples were used for the analysis of immediate and more permanent tissue mineral status, respectively. Samples taken from a control non-athletic female group and two groups of female athletes (field hockey and fencing) were analyzed for seven essential minerals: calcium, chromium, iron, potassium, magnesium, selenium and zinc. Inductively-coupled plasma mass spectrometry was used for the quantification of elements having very low concentration range in samples (Se, Cr and Zn) whereas inductively coupled plasma optical emission spectrometry was used for quantification of more ubiquitous elements (Mg, К, Са, Fe). The obtained results for athletic groups were compared with control. Female athletes had increased levels of selenium in both saliva and hair as well as chromium in saliva. Field hockey players had the higher level of zinc in hair whereas fencers had the lower levels of salivary calcium. Strong negative correlation between potassium levels in saliva and hair was identified. Iron and magnesium did not differ between the studied groups. In conclusion, novel sport-specific features of chromium tissue levels in female athletes were found. The studied sport disciplines have different impact on the distribution of osteoporosis-related minerals (calcium and zinc). Our finding can help in the development of osteoporosis preventive trainings and in the proper nutrient supplementation to correct mineral imbalances in female athletes.

Bone Variables in Active Overweight/Obese Men and Sedentary Overweight/Obese Men

The aim of this study was to compare bone variables in active overweight/obese men and sedentary overweight/obese men. Thirty-seven active overweight/obese men and 45 sedentary overweight/obese men participated in this study. Weight and height were measured, and body mass index was calculated. Body composition and bone variables (bone mineral content [BMC], bone mineral density [BMD], geometric indices of hip bone strength, and trabecular bone score) were measured by DXA. Physical activity level, daily calcium intake, daily protein intake, and sleep duration were measured by validated questionnaires. Maximum oxygen consumption (VO₂ max) was determined by direct measurement while exercising on a medical treadmill. One-repetition-maximum half-squat of the lower limbs was measured using a validated protocol. Body weight and body mass index were higher in sedentary overweight/obese men than in active overweight/obese men. In the whole population (n = 82), VO₂ max (in liter per minute), lean mass, and one-repetition-maximum half-squat were positively correlated to BMC, BMD, and geometric indices of hip bone strength (cross-sectional area and section modulus [Z] of the femoral neck [FN]). After adjusting for body weight using a 1-way analysis of covariance, active overweight/obese men displayed higher whole-body BMC, lumbar spine BMD, total hip BMD, FN BMD, FN cross-sectional area, and FN Z values than sedentary overweight/obese men. In conclusion, the current study suggests that physical activity level positively affects bone variables in overweight/obese men. Optimizing lean mass and muscular strength of the lower limbs can help to prevent osteoporosis in overweight and obese men.

High Cardiorespiratory Fitness Is Associated with Reduced Risk of Low Bone Density in Postmenopausal Women

PURPOSE

The goal of this study was to determine the association between cardiorespiratory fitness (CRF) and bone mineral density (BMD) of the femoral neck (FN) in postmenopausal women using existing Cooper Center Longitudinal Study data.

MATERIALS AND METHODS

A cohort of 1,720 predominantly healthy Caucasian women (57.1 ± 6.9 years) underwent preventive medical examinations that included CRF assessment by maximal Balke treadmill testing and measurement of BMD by dual-energy X-ray absorptiometry. CRF was estimated from total treadmill time and categorized into five categories of CRF (further defined as fitness category 1 = low fitness, 2-3 = moderate fitness, and 4-5 = high fitness). Logistic regression was used to characterize the association between CRF and BMD, adjusting for age, weight, and resistance activity level.

RESULTS

Overall, the mean body-mass index (BMI) for all subjects was 25.0 ± 4.5 kg/m2, although BMI was in the obese range in the low fitness group. The prevalence of osteoporosis (T-score ≤ -2.5 at the FN) was greater in the low fit group than moderate or high fit (5.8% vs. 3.0% or 3.9%, respectively); with a similar pattern seen for prevalence of osteopenia (T-score > -2.5 and ≤ -1.0 at the FN) (47.5% vs. 46.4% or 44.8%, respectively). Higher age and lower weight were associated with low BMD. Fully adjusted logistic regression models showed an inverse association between CRF and low BMD of the FN. For T-score ≤ -1.0, the primary outcome, the odds ratio (OR) was 0.50 (95% confidence interval [CI] 0.32-0.79) for moderate fitness, and OR of 0.32 (95% CI 0.21-0.51) for high fitness was seen. For T-score ≤ -2.5 at the FN, OR was 0.30 (95% CI 0.11-0.80) for moderate fitness, and OR was 0.29 (95% CI 0.12-0.71) for high fitness.

CONCLUSION

Increased CRF levels are associated with reduced risk for low bone density in postmenopausal women.

Associations between Bone Mineral Characteristics and Serum Levels of Ghrelin and Peptide YY in Overweight Adolescent Boys

BACKGROUND/AIMS

The role of ghrelin and peptide YY (PYY) in bone mineralization is not fully known. The aim of this study was to determine whether acylated and des-acyl ghrelin and PYY in addition to leptin are related to bone mineral density (BMD) in adolescent overweight boys (OWB) and normal-weight boys (NWB).

PARTICIPANTS AND METHODS

Fifty- five OWB (BMI >85th percentile) and 154 NWB (BMI <85th percentile) aged 12-16 years participated in this study. Fasting serum acylated and des-acyl ghrelin, PYY, leptin, testosterone levels, total body (TB) and lumbar spine (LS) bone mineral content (BMC), and BMD were measured. TB BMC for height and TB and LS bone mineral apparent density (BMAD) were calculated.

RESULTS

No differences were seen in acylated and des-acyl ghrelin or PYY levels, while the leptin levels were significantly higher in the OWB compared to the NWB. In the OWB, TB BMAD was positively correlated with acylated ghrelin and leptin, and TB BMC for height was positively correlated with PYY. In the OWB, the variability of TB BMD was determined by TB fat-free mass and des-acyl ghrelin, whereas the variability of TB BMAD was determined by leptin.

CONCLUSIONS

Des-acyl ghrelin and PYY are involved in the bone mineralization process in puberty, and the impact can vary between normal and overweight subjects.

Muscle strength, power and cardiorespiratory fitness are associated with bone mineral density in men aged 31-60 years

BACKGROUND

Osteoporotic fractures represent a growing economical burden to society, not only because of fractures in women, but also because of an increasing number of fractures in men.

AIMS

In this cross-sectional study we aimed to investigate the association of muscular and cardio-respiratory fitness with BMD at the spine and hip in men.

RESULTS

The association between independent variables maximal aerobic capacity (VO(2max)), leg power and hand grip strength, and dependent variables BMD at the spine and total hip was explored in a series of linear regression models successively adjusted for age, weight and height, smoking, alcohol intake and leisure time physical activity level. In the fully adjusted model we found a significant association of VO(2max) with BMD at the lumbar spine, p<0.0089. Furthermore, we observed significant associations of VO(2max) (p<0.0022) and leg power (p<0.011) with BMD at total hip.

CONCLUSIONS

We found that cardiorespiratory fitness was associated with BMD in men. Furthermore, hand grip strength and leg power were associated with increasing BMD at the lumbar spine and total hip in men, respectively. Further prospective studies are needed to further investigate the association between physical activity and BMD in men.