Polar Strength Strain Index Research Articles

High muscular fitness level may positively affect bone strength and body composition in children with overweight and obesity

SummaryMuscular fitness plays a major role in bone health and body composition in overweight and obese children. It is key that the development of this muscle fitness is affected by absolute isometric strength and dynamic strength.PurposeTo compare bone health and body composition between overweight/obese children considering muscular fitness (MF) levels, and to investigate whether weight-bearing dynamic or absolute isometric strength, both involved in the development of this muscular fitness, are more related with bone health.MethodsMF of 59 overweight or obese children (10.1 ± 0.9 years, 27 females) was measured by a countermovement jump (CMJ), handgrip, and maximal isometric strength of knee extension. Participants were divided into four groups depending on their MF level performing a cluster analysis: 16 children with high MF (HMF) in all tests, 18 with high performance in isometric strength (HIS), 15 with high performance in CMJ (HCMJ) and 10 low isometric and low dynamic force values (LMF). Body composition values were measured by dual energy X-ray absorptiometry, and bone strength values were assessed by peripheral quantitative computed tomography. Motor skills were evaluated using TGMD-3. Multivariate analysis of covariance test was applied to analyse bone strength differences between children in the different MF groups, using maturity offset, height and weight as covariates, and correlations were investigated.ResultsHMF excelled in bone health. HIS had higher cortical bone area, periosteal circumference, bone mass, polar strength strain index and fracture load than LMF, while HCMJ only showed better results in trabecular bone area than LMF. HMF had significantly better values of fracture load and periosteal and endosteal circumferences than HCMJ, but not than HIS.ConclusionsHigh MF level shows positive effects on bone health in overweight/obese children. Those with highest isometric strength had better bone health compared to those with higher dynamic strength.Trial registrationThe research project was registered in a public database Clinicaltrials.gov in June 2020 with the identification number NCT04418713.

Comparison of the strength parameters of the bilateral third metacarpal bones in horses by pQCT

The third metacarpal (MC3) bone, along with the proximal phalanx, is one of the bones that are most prone to injury in sport horses. To date, no detailed analysis has been conducted that would compare the strength parameters of bilateral MC3 bones taking into account differences depending on the site of measurement. The aim of the study was to compare strength parameters between the left and right MC3 bones in horses at 10%, 20%, 30%, 40%, 50%, 60%, 70% and 80% of the bone length using peripheral quantitative computed tomography (pQCT). The research material comprised isolated bilateral MC3 bones from 21 horses (age range: 3-27 years). The structure of these bones was measured using high-resolution pQCT. The following bone parameters were determined: polar strength strain index, strength strain index X and strength strain index Y. The computed tomographic analysis of the MC3 bones was carried out at sections from 10% to 80% (every 10%) of the bone length. The statistical analysis showed that in most cases the strength parameters calculated using pQCT were significantly higher for the right MC3 bones at 10%, 20% and 50% of the bone length, i.e. at the proximal metaphysis and at the proximal diaphysis. However, strength parameters measured at 60% and 80% of the diaphyseal length, i.e. at the distal diaphysis, were significantly higher for the left MC3 bones. Further studies of the MC3 bones parameters should focus on the vicinity of the proximal metaphysis and at the proximal diaphysis.

Peak vertical jump power predicts radial bone strength better than hand grip strength in healthy individuals.

Osteoporosis is considered a pediatric disease with geriatric consequences. However, measuring bone strength in children is complex and creates a practical problem for health professionals, teachers and parents. A non-invasive measure of muscle fitness that correlates to bone strength may provide a means to monitor bone strength throughout the lifespan. Therefore, the purpose of this study was to investigate the relationship between common muscle function tests (relative grip strength (RGS), peak vertical jump power (PP)) and bone strength in the radial diaphysis and epiphysis of a healthy population. Healthy participants (n=147 (81 female)) performed a bilateral grip strength test using a hand dynamometer, and a maximal vertical jump test. Peak vertical jump power was calculated from maximal jump height using the Sayer’s equation. Moment of inertia (MoI), cortical area (CoA), cortical bone mineral density (cBMD), and polar strength-strain index (SSIp) were measured using peripheral Quantitative Computed Tomography (pQCT) to determine bone strength parameters at the 66% radial site (predominantly cortical bone). At the 4% site (trabecular bone site), bone mineral content (vBMC.tb), bone mineral density (vBMD.tb), total area (ToA.tb) and bone strength index (BSIc) were measured. Hierarchical multiple regression analyses determined the relationship of each muscle function test for each bone envelope (cortical and trabecular). For the cortical bone measurements: RGS, and PP were both significantly correlated with CoA, MoI, and SSIp. Peak vertical jump power predicted bone strength parameters to a greater extent compared to RGS. For the trabecular bone envelope, RGS was not a predictor of bone strength however peak power was a significant predictor of bone strength parameters. Peak vertical jump power was a significant predictor of bone strength at both trabecular and cortical radial sites. Interestingly PP, a lower limb measurement explained the most variance in the bone strength of the upper limb.

Evaluation of Femoral Bone Fracture Healing in Rats by the Modal Damping Factor and Its Correlation With Peripheral Quantitative Computed Tomography.

IntroductionMonitoring the progress of fracture healing is essential in order to establish the appropriate timing that ensures adequate bone strength for weight-bearing. In the present experimental study on a rat model of femoral fracture healing, the measurement of bone density and strength by peripheral quantitative computerized tomography (pQCT) was correlated with the modal damping factor (MDF) method.MethodsFour groups of 12 male six-month-old Wistar rats each were anesthetized and submitted to baseline femoral pQCT and MDF scanning, followed by aseptic midshaft osteotomy of the right femur which was fixed by a locking intramedullary nail technique. The animals were left to recover and re-scanned following euthanasia of each group after six, eight, 10, and 12 weeks, respectively. The parameters measured by the pQCT method were total bone mineral density (BMD) and polar strength strain index (SSIp).ResultsFracture healing progressed over time and at 12 weeks post-osteotomy there was no statistically significant difference between the osteotomized right and the control left femurs regarding MDF, BMD, and SSIp measurements. The highest correlations for the osteotomized femurs were observed between MDF and BMD (r = -0.647, P = 0.043), and between MDF and SSIp (r = -0.350, P = 0.321), at 10 weeks postoperatively. The high to moderate correlations between MDF and BMD, and between MDF and SSIp respectively, support the validity of MDF in assessing fracture healing.ConclusionsBased on our findings in this fracture healing animal model, the results from the MDF method are reliable and correlate highly with the total BMD and moderately with the SSI polar values obtained by the pQCT method of bone quality measurement. Further studies are needed which may additionally support that the MDF method can be an attractive portable alternative to monitor fracture healing in the community.

Influence of Changes in Soft Tissue Composition on Changes in Bone Strength in Peripubertal Girls: The STAR Longitudinal Study.

Obesity and osteoporosis remain two major public health concerns. Soft tissue composition and bone are interrelated; however, it is still not well understood how changes in adiposity during adolescence affect bone development. The aim of this study was to assess how changes in DXA-derived total body lean mass (TBLM) and total body fat mass (TBFM) associate with 2-year changes in bone outcomes at the 20% femur, 66% tibia, 66% radius, and 4% tibia, as measured by pQCT, during the years surrounding the onset of menarche in a cohort of 9- to 12-year-old (baseline) adolescent girls (70% Hispanic). From baseline to 2-year follow-up, girls showed statistically significant increases in all bone outcomes, except radial endosteal circumference. In separate linear regression models, change in TBLM and change in TBFM were both positively associated with 2-year changes in bone outcomes at all measured bone sites, after controlling for relevant covariates. However, when change in TBLM and change in TBFM were included in the same model, change in TBLM was the predominant predictor of bone outcomes, explaining 4% to 14% of the variance in bone strength outcomes. Change in TBFM remained a positive predictor of tibia polar strength strain index (SSIp) (2% variance explained). A significant interaction between change in TBFM and menarcheal status was identified at the radius for SSIp and indicated that greater gains in TBFM were beneficial for SSIp in girls that were premenarcheal at baseline but detrimental for girls who were postmenarcheal at baseline. The overall findings suggest that changes in TBLM during the peripubertal years have a greater influence on bone outcomes than changes in TBFM. While gains in TBFM might benefit the weight bearing 66% tibia, greater gains in TBFM may be detrimental to bone development at the non-weight bearing 66% radius after the onset of menarche. © 2020 American Society for Bone and Mineral Research (ASBMR).

Oral administration of melatonin contained in drinking water increased bone strength in naturally aged mice

Melatonin has recently been found to be a possible new regulator of bone metabolism. However, the influence of melatonin in natural age-related osteoporosis has not been fully elucidated yet, although there have been some reports regarding postmenopausal osteoporosis with melatonin treatments. The present study investigated the effects of long-term melatonin administration during the aging process on bone metabolism. Using quantitative computed tomography methods, we found that the total bone density of both the femur metaphysis and diaphysis decreased significantly in 20-month-old male mice. In the metaphysis, both trabecular bone mass and Polar-Strength Strain Index (SSI), which is an index of bone strength, decreased significantly. Judging from bone histomorphometry analysis, trabecular bone in 20-month-old male mice decreases significantly with age and is small and sparse, as compared to that of 4-month-old male mice. Loss of trabecular bone is one possible cause of loss of bone strength in the femoral bone. In the metaphysis, the melatonin administration group had significantly higher trabecular bone density than the non-administration group. The Polar-SSI, cortical area, and periosteal circumference in the diaphysis was also significantly higher with melatonin treatments. Since the melatonin receptor, MT2, was detected in both osteoblasts and osteoclasts of the femoral bone of male mice, we expect that melatonin acts on osteoblasts and osteoclasts to maintain the bone strength of the diaphysis and metaphysis. Thus, melatonin is a potential drug for natural age-related osteoporosis.

Muscle Power Predicts Bone Strength in Division II Athletes.

Yingling, VR, Webb, SL, Inouye, C, O, J, and Sherwood, JJ. Muscle power predicts bone strength in Division II athletes. J Strength Cond Res 34(6): 1657-1665, 2020-The relationship between muscle fitness measures and tibial bone strength in collegiate level athletes was investigated. Eighty-six Division II collegiate athletes (mean ± SD: age: [18-29 years], height: 1.71 m [0.09], mass: 66.7 kg [10.5], 56 female: 30 male) participated in this cross-sectional study. Maximum grip strength (GS), 1 repetition maximum leg press, and vertical jump peak power (PP) tests were measured. Cortical area, cortical bone mineral density (cBMD), moment of inertia, and bone strength (polar strength-strain index) were measured using peripheral quantitative computed tomography at 50% tibia length. For each bone strength parameter, a hierarchical multiple regression analysis was performed to examine the contribution of sex and the 3 muscle fitness parameters (muscle power, relative 1 repetition leg extensor strength, and relative GS) to bone parameters. Vertical jump PP explained 54-59% of the variance in bone strength parameters, and relative leg extensor and GS were not predictive of bone strength parameters. Muscle power correlated with bone mass and architecture variables but not cBMD values. Cortical bone mineral density was also not predicted by relative leg extensor strength or relative GS. Muscular fitness assessment, specifically PP calculated from vertical jump height assessments, provides a simple, objective, valid, and reliable measure to identify and monitor bone strength in collegiate athletes.

Association Between Physical Fitness and Bone Strength and Structure in 3- to 5-Year-Old Children.

The positive association between physical fitness and bone structure has been widely investigated in children and adolescents, yet no studies have evaluated this influence in young children (ie, preschoolers). Fit children will present improved bone variables when compared with unfit children, and no sex-based differences will emerge in the sample. Cross-sectional study. Level 3. Handgrip strength, standing long jump (SLJ), speed/agility, balance, and cardiorespiratory fitness (CRF) were assessed using the Assessing FITness levels in PREschoolers (PREFIT) test battery in 92 children (50 boys; age range, 3-5 years). A peripheral quantitative computed tomography scan was performed at 38% of the length of the nondominant tibia. Cluster analysis from handgrip strength, SLJ, speed/agility, and CRF was developed to identify fitness groups. Bone variables were compared between sexes and between cluster groups. The association between individual physical fitness components and different bone variables was also tested. Three cluster groups emerged: fit (high values on all included physical fitness variables), strong (high strength values and low speed/agility and CRF), and unfit (low strength, speed/agility, and CRF). The fit group presented higher values than the strong and unfit groups for total and cortical bone mineral content, cortical area, and polar strength strain index (all P < 0.05). The fit group also presented a higher cortical thickness when compared with the unfit group (P < 0.05). Handgrip, SLJ, and speed/agility predicted all bone variables except for total and cortical volumetric bone mineral density. No differences were found for bone variables between sexes. The results suggest that global fitness in preschoolers is a key determinant for bone structure and strength but not volumetric bone mineral density. Physical fitness is a determinant for tibial bone mineral content, structure, and strength in very young children. Performing physical fitness tests could provide useful information related to bone health in preschoolers.

Deficits in Bone Architecture and Strength in Children Living With HIV on Antiretroviral Therapy.

Reduced bone mineral mass by dual x-ray absorptiometry is reported in children living with HIV (CLWH), but few studies of bone microarchitecture, particularly in sub-Saharan Africa, have been conducted. Here, we compare bone architecture and strength in black South African CLWH and uninfected control children by peripheral quantitative computed tomography (pQCT). One hundred seventy-two CLWH on antiretroviral therapy (ART) and 98 controls in the CHANGES Bone Study in Johannesburg, South Africa received pQCT scans of the radius and tibia. Measurements included trabecular and cortical volumetric bone mineral density (vBMD) and bone strength, estimated by the polar strength strain index (SSI), a validated measure of fracture risk. CLWH (51% boys) and controls (63% boys) were an average of age 10.4 years. Mean ART duration for CLWH was 9.5 years, with 70.9% on an efavirenz-based, 28.5% on a lopinavir/ritonavir-based, and 1 child on an atazanavir/ritonavir-based regimen. Male CLWH had lower trabecular vBMD at the radius than controls after adjustment for age, radial length, and Tanner stage (β = -17.3, standard error = 7.2, P = 0.018). Bone strength by polar SSI was lower in CLWH than controls (778 vs. 972 mm, P < 0.01). CLWH on an LPV/r-based regimen had lower trabecular vBMD (199 vs. 222 mg/cm, P < 0.001) and cortical vBMD (1074 vs. 1093 mg/cm, P = 0.004) than those on an efavirenz-based regimen. No difference in bone strength by polar SSI was observed between treatment groups. CLWH initiated on ART early in life with well-controlled HIV have deficits in bone architecture and reductions in bone strength as detected by pQCT.

An 8-Year Longitudinal Analysis of Physical Activity and Bone Strength From Adolescence to Emerging Adulthood: The Iowa Bone Development Study.

Most pediatric physical activity and bone health research has focused on the period immediately around puberty; few have addressed bone structural strength outcomes. This study assessed the magnitude and consistency of the longitudinal relationships between device-measured vigorous-intensity physical activity (VPA) and structural bone strength outcomes across adolescence to emerging adulthood. Participants with 3 to 5 bone scans between the age of 11 and 19 years were studied (N = 439, 220 females, 1838 records). Dual-energy X-ray absorptiometry scans of the hip (hip structural analysis) and peripheral quantitative computed tomography scans of the tibia were obtained. Outcomes included femoral neck section modulus, femoral neck cross-sectional area, tibial Bone Strength Index, and tibial torsion strength (polar Strength Strain Index). Sex-specific bone mixed growth models were developed using biological age (chronological age - age at peak height velocity) as the time variable, and height, weight, and device-measured VPA as time-varying covariates. Models also included the VPA-biological age interaction. Individual-centered VPA and the VPA-biological age interaction were significantly, positively associated (P < .05) with Bone Strength Index, polar Strength Strain Index, section modulus, and cross-sectional area in males and females, indicating accumulative effects of VPA throughout maturation and beyond. Bone remains responsive to the mechanical loading of physical activity throughout adolescence and into emerging adulthood. Attention should be placed on promoting bone-strengthening physical activity after the prepubertal years when adult exercise patterns are likely formed.

Bone geometry and lower extremity bone stress injuries in male runners

Bone stress injuries (BSI) are common among distance runners and research investigations examining risk factors for BSI among men are limited. Therefore, investigations are needed to determine if men with a history of BSI have skeletal properties that may heighten BSI incidence. ObjectivesTo analyze differences in bone density, bone geometry, and estimates of bone strength in male runners with and without a BSI history. DesignCross-sectional. MethodsWe recruited 36 male distance runners ages 18–41 for this study. We used peripheral quantitative computed tomography (pQCT) to assess volumetric bone mineral density (vBMD, mg/mm3), bone geometry (total and cortical bone area, mm2), tibia robustness (total area/tibia length, mm) and estimates of bone strength (section modulus and polar strength-strain index, mm3) at 5 tibial sites. ResultsAfter adjusting for age, the BSI group had more slender tibias (9%), lower stress strain indices (−16%), lower section moduli (−17%) and smaller total cross-sectional (−11%) and cortical areas (−12%) at the 66% site of the tibia compared with controls (P < 0.05 for all). Similar differences were found at all other measurement sites. After adjusting for body size, differences in bone outcomes remained significant at the 66% site. ConclusionsThese results indicate that men with a history of BSI have lower estimated bending strength compared to controls because of narrower tibias. However, differences are largely attenuated in the distal ½ of the tibia after adjusting for body size. Thus, smaller tibia size, particularly at the mid-diaphysis, may be an important indicator for BSI incidence.

Middle School Recreational Sport Participation as a Determinant of Adult Muscle and Bone Strength

Physical activity during adolescence promotes the development of skeletal strength and muscle function. Musculoskeletal adaptations result from mechanical forces common in sporting activities. Recent studies have reported strong positive correlations between muscle power and bone strength (Janz, 2015, Yingling, 2017). PURPOSE: To determine if participation in middle school sports (self-report questionnaire) resulted in greater muscle and bone strength later in life. METHODS: 79 participants, 41 female and 38 male (age (yrs) 29.2 + 10.8, height (cm) 166.5 + 9.2, body fat (%) 24.6 + 9.3) performed a Relative Grip Strength (RGS) test using a hand grip dynamometer, 1 Repetition Maximum leg extension test (1RM), and a vertical jump test. Peak Power (PP) was calculated from jump height (Sayers, 1999). Peripheral Quantitative Computed Tomography (pQCT) was used to measure bone strength (polar Strength-Strain Index (SSIp)) in the cortical region of the tibia and radius. A questionnaire completed by participants stated “Did you participate in recreational sports during middle school (Grades 6-8)?” Welch’s t-test determined differences in the muscle function tests and bone strength measures based on middle-school sports participation. RESULTS: 55 individuals participated in recreational sports during middle school, 16 individuals did not. Those who participated in sports during middle school had an average relative PP of 55.41 W/kg, RGS of 6.46 N/kg, 1RM of 2.86 RW/BM, radial SSIp of 279.31 mm3, and tibial SSIp of 2036.13 mm3. Individuals that did not participate in recreational sports during middle school had an average PP of 49.12 W/kg, RGS of 5.58 N/kg, 1RM of 2.45RW/BM, radial SSI of 268.49 mm3, tibial SSI of 1957.50 mm3. Middle school sports participation resulted in significantly greater PP (p = 0.008), RGS (p = 0.010) and 1RM (p = 0.018) but no differences were found for bone strength in either the radius or tibia. CONCLUSIONS: Adolescence is a key time for bone and muscle strength adaptation. However, the results suggest that self report of middle school recreational sport involvement may not be an optimal way to predict muscle and bone strength in adulthood. . Evaluating past activity by survey has limitations with self-reported activity including the inability to determine the intensity of activity.

Perceived Quantity of Physical Activity as a Reflective Measure in Muscle and Bone Strength

Perception plays a powerful role in shaping health outcomes. An active lifestyle, provides mechanical load needed to strengthen and maintain both muscle and bone health. Many recommendations on the quantity of physical activity needed for health benefits exist however it is unclear if individuals perception of their activity habits relates to muscle and bone strength benefits. PURPOSE: To determine if those who perceived that they get the right amount or more than needed amount of exercise, have greater muscle and bone strength. METHODS: 79 participants, 41 females and 38 males (age (yrs) 29.2 + 10.8, height (cm) 166.5 + 9.2, body fat % 24.6 + 9.3) performed a relative grip strength (RGS) test using a hand grip dynamometer, 1 repetition maximum leg extension test (1RM), and a vertical jump test using a Vertec (PP). Bone Strength Index (compression) (BSIc) and polar Strength-Strain Index (SSIp) were measured using peripheral Quantitative Computed Tomography (pQCT). A questionnaire stated “Do you feel you get too much exercise, too little exercise, or about the right amount of exercise?” Welch’s t-tests detected differences in muscle function and bone strength based on perception of exercise quantity (Above and Below). RESULTS: 41 participants perceived they got the “right amount of exercise or above” (Above) and 29 participants reported that they got below the right amount of exercise (Below). Perception of the Above group resulted in greater muscle function tests compared to the Below group (Average PP: 11.5% (p=0.004), RGS: 5.7% (p=0.004). “Right amount of exercise or above” resulted in greater bone strength (SSIp) at both the radius (11.7% (p=0.055) and tibia (13.3% p=0.02). CONCLUSIONS: Participants’ perception on quantity of exercise reflected their bone and muscle strength. Those who perceived that they get the appropriate or a higher amount of exercise had greater bone and muscle strength values compared to participants’ who perceived they exercised less. Perception of getting the “right amount of exercise or above” compared to “below right amount of exercise” was a good indicator of greater bone and muscle strength.

The muscle-bone unit in adolescent swimmers.

To examine the functional and structural muscle-bone unit in adolescent swimmers. Sixty-five swimmers (34 girls/31 boys) and 119 controls (51 girls/68 boys) participated in the study. Muscle cross-sectional area (MCSA), bone mineral content (BMC), and polar strength-strain index (SSIPOL) were measured in the non-dominant radius by peripheral quantitative computed tomography (pQCT). Subtotal BMC and lean mass were evaluated with dual-energy X-ray absorptiometry (DXA). Handgrip and isometric knee extension (IKE) tests were performed to determine muscle force. The effect of MCSA, lean and force on SSIPOL, and BMC were tested, and the functional and structural muscle-bone ratios of swimmers and controls were compared. Both muscle size (MCSA and lean) and muscle force (handgrip and IKE) influenced BMC and SSIPOL in swimmers and controls similarly. Swimmers presented normal MCSA and lean values for their height, but when compared with controls, swimmers presented a higher amount of lean and MCSA for the same BMC or SSIPOL (structural muscle-bone unit). For the functional muscle-bone unit, different results were found for the lower and upper limbs, as no differences were found for the upper limbs, while for the lower limbs, swimmers presented higher muscle force for the same amount of BMC. The contradictory results regarding BMC in swimmers found in previous studies could partly be explained with the findings of the present study that reinforce the idea that swimming is not an effective sport to practice regarding bone mass and that the muscle-bone unit is different in swimmers than in controls.

Tibia functionality and Division II female and male collegiate athletes from multiple sports

BackgroundBone strength is developed through a combination of the size and shape (architecture) of a bone as well as the bone’s material properties; and therefore, no one outcome variable can measure a positive or negative adaptation in bone. Skeletal robusticity (total area/ bone length) a measure of bones external size varies within the population and is independent of body size, but robusticity has been associated with bone strength. Athletes may have similar variability in robusticity values as the general population and thus have a wide range of bone strengths based on the robustness of their bones. Therefore, the purpose of this study was to determine if an athlete’s bone strength and cortical area relative to body size was dependent on robusticity. The second aim was to determine if anthropometry or muscle function measurements were associated with bone robusticity.MethodsBone variables contributing to bone strength were measured in collegiate athletes and a reference group using peripheral quantitative computed tomography (pQCT) at the 50% tibial site. Bone functionality was assessed by plotting bone strength and cortical area vs body size (body weight x tibial length) and robustness (total area/length) vs body size. Bone strength was measured using the polar strength-strain index (SSIp). Based on the residuals from the regression, an athlete’s individual functionality was determined, and two groups were formed “weaker for size” (WS) and “stronger for size” (SS). Grip strength, leg extensor strength and lower body power were also measured.ResultsDivision II athletes exhibited a natural variation in (SSIp) relative to robusticity consistent with previous studies. Bone strength (SSIp) was dependent on the robusticity of the tibia. The bone traits that comprise bone strength (SSIp) were significantly different between the SS and WS groups, yet there were minimal differences in the anthropometric data and muscle function measures between groups. A lower percentage of athletes from ball sports were “weaker for size” (WS group) and a higher percentage of swimmers were in the WS group.DiscussionA range of strength values based on robusticity occurs in athletes similar to general populations. Bones with lower robusticity (slender) were constructed with less bone tissue and had less strength. The athletes with slender bones were from all sports including track and field and ball sports but the majority were swimmers.ConclusionsAthletes, even after optimal training for their sport, may have weaker bones based on robusticity. Slender bones may therefore be at a higher risk for fracture under extreme loading events but also yield benefits to some athletes (swimmers) due to their lower bone mass.

Diet Quality and Bone Measurements Using HRpQCT and pQCT in Older Community-Dwelling Adults from the Hertfordshire Cohort Study

There are few data describing associations between dietary patterns and bone microarchitecture. This study investigated the relationship between diet quality and HRpQCT and pQCT measures in older adults. Data were available for 184 men and 166 women. Dietary data were collected at baseline (1998–2003) using an administered food frequency questionnaire. A ‘prudent’ diet score (PDS) was identified using principal component analysis and used as an indicator of dietary quality. HRpQCT and pQCT images were acquired at follow-up in 2012, from the non-dominant distal radius and tibia using Scanco XtremeCT and Stratec XCT2000 instrument scanners, respectively. The mean (SD) PDS was − 0.24 (1.23) for men and 0.62 (1.14) for women. In women, a significant positive relationship was found between baseline dietary pattern and total and trabecular area at both the radius and the tibia, measured by HRpQCT. Similar trends were observed with pQCT parameters. Positive associations were observed for tibia total area (38% slice). At the radius, significant positive associations were found for total area (4% slice) and polar strength strain index (33% slice). All relationships remained robust to adjustment. For men, although patterns were similar, there were no significant associations for HRpQCT outcomes. Significant associations were observed for baseline PDS and polar strength strain and total area (66% slice) at the radius, measured by pQCT. Our data suggest that diets high in fruit, vegetables, oily fish and whole grain cereals in early old age are associated with greater bone size but not volumetric bone density or microarchitecture in later life in women.

Sex-difference in bone architecture and bone fragility in Vietnamese

This study sought to define the sex-difference in trabecular and cortical bone parameters in Vietnamese individuals. The study involved 1404 women and 864 men aged between 20 and 86 years who were recruited from Ho Chi Minh City, Vietnam. Trabecular and cortical volumetric BMD were measured at the proximal tibia and proximal radius at 4%, 38%, and 66% points, using a peripheral quantitative computed tomography XCT2000 (Stratec, Germany). Polar strength strain index was estimated from cortical bone parameters. Changes in bone parameters were assessed by the multiple linear regression model. Among individuals aged 20–39 years, women had significantly lower peak trabecular BMD at both the radius (40%) and tibia (16%) than men, but the age-related reduction in trabecular BMD were similar between two sexes. For cortical BMD, peak values in women and men were comparable, but the age-related diminution was greater in women than men. At any age, polar strength strain index in women was lower than men, and the difference was mainly attributable to cortical bone area and total bone mass. We conclude that in the elderly, sex-related difference in trabecular BMD is originated during growth, but sex-related difference in cortical BMD is determined by differential age-related bone loss.

Bone geometry in young male and female football players: a peripheral quantitative computed tomography (pQCT) study.

The aim of this study was to compare bone geometry in adolescent football players and controls. A total of 107 football players (71 males/36 females; mean age 12.7 ± 0.6/12.7 ± 0.6years) and 42 controls (20 males/22 females; mean age 13.1 ± 1.4/12.7 ± 1.3years) participated in this study. Total and trabecular volumetric bone mineral content (Tt.BMC/Tb.BMC), cross-sectional area (Tt.Ar/Tb.Ar), and bone strength index (BSI) were measured at 4% site of the non-dominant tibia by peripheral quantitative computed tomography (pQCT). Moreover, Tt.BMC, cortical BMC (Ct.BMC), Tt.Ar, cortical Ar (Ct.Ar), cortical thickness (Ct.Th), periosteal circumference (PC), endosteal circumference (EC), fracture load in X-axis, and polar strength strain index (SSIp) were measured at 38% site of the tibia. Multivariate analyses of covariance were used to compare bone pQCT variables between football players and controls using the tibia length and maturity offset as covariates. Female football players demonstrated 13.8-16.4% higher BSI, Ct.Th, fracture load in X-axis, and SSIp than controls (p < .0036). Males showed no significant differences in bone strength when compared to controls (p > .0036). In relation to bone mineral content and area, male football players showed 8.8% higher Tt.Ar and Tb.Ar at the 4% site of the tibia when compared to controls; whereas 13.8-15.8% higher Tt.BMC, Ct.BMC, and Ct.Ar at the 38% site of the tibia were found in female football players than controls (p < .0036). In this study, female adolescent football players presented better bone geometry and strength values than controls. In contrast, only bone geometry was higher in male football players than controls.

Whole egg consumption and cortical bone in healthy children.

This study examined the relationships between egg consumption and cortical bone in children. The cross-sectional study design included 294 9-13-year-old black and white males and females. Three-day diet records determined daily egg consumption. Peripheral quantitative computed tomography measured radius and tibia cortical bone. Body composition and biomarkers of bone turnover were assessed using dual-energy X-ray absorptiometry and ELISA, respectively. Egg intake was positively correlated with radius and tibia cortical bone mineral content (Ct.BMC), total bone area, cortical area, cortical thickness, periosteal circumference, and polar strength strain index in unadjusted models (r = 0.144-0.224, all P < 0.050). After adjusting for differences in race, sex, maturation, fat-free soft tissue mass (FFST), and protein intakes, tibia relationships were nullified; however, egg intake remained positively correlated with radius Ct.BMC (r = 0.138, P = 0.031). Egg intake positively correlated with total body bone mineral density, BMC, and bone area in the unadjusted models only (r = 0.119-0.224; all P < 0.050). After adjusting for covariates, egg intake was a positive predictor of radius FFST (β = 0.113, P < 0.050) and FFST was a positive predictor of Ct.BMC (β = 0.556, P < 0.050) in path analyses. There was a direct influence of egg on radius Ct.BMC (β = 0.099, P = 0.035), even after adjusting for the mediator, FFST (β = 0.137, P = 0.020). Egg intake was positively correlated with osteocalcin in both the unadjusted (P = 0.005) and adjusted (P = 0.049) models. If the positive influence of eggs on Ct.BMC observed in this study is confirmed through future randomized controlled trials, whole eggs may represent a viable strategy to promote pediatric bone development and prevent fractures.

Physical activity, but not sedentary time, influences bone strength in late adolescence.

To examine the influence of physical activity (PA) and sedentary time on bone strength, structure, and density in older adolescents. We used peripheral quantitative computed tomography to estimate bone strength at the distal tibia (8% site; bone strength index, BSI) and tibial midshaft (50% site; polar strength strain index, SSIp) in adolescent boys (n = 86; 15.3 ± 0.4years) and girls (n = 106; 15.3 ± 0.4years). Using accelerometers (GT1M, Actigraph), we measured moderate-to-vigorous PA (MVPAAccel), vigorous PA (VPAAccel), and sedentary time in addition to self-reported MVPA (MVPAPAQ-A) and impact PA (ImpactPAPAQ-A). We examined relations between PA and sedentary time and bone outcomes, adjusting for ethnicity, maturity, tibial length, and total body lean mass. At the distal tibia, MVPAAccel and VPAAccel positively predicted BSI (explained 6-7% of the variance, p < 0.05). After adjusting for lean mass, only VPAAccel explained residual variance in BSI. At the tibial midshaft, MVPAAccel, but not VPAAccel, positively predicted SSIp (explained 3% of the variance, p = 0.01). Lean mass attenuated this association. MVPAPAQ-A and ImpactPAPAQ-A also positively predicted BSI and SSIp (explained 2-4% of the variance, p < 0.05), but only ImpactPAPAQ-A explained residual variance in BSI after accounting for lean mass. Sedentary time did not independently predict bone strength at either site. Greater tibial bone strength in active adolescents is mediated, in part, by lean mass. Despite spending most of their day in sedentary pursuits, adolescents' bone strength was not negatively influenced by sedentary time.