Bone Strength Index Research Articles

Structural differences in cortical shell properties between upper and lower human fibula as described by pQCT serial scans. A biomechanical interpretation

This study describes the structural features of fibula cortical shell as allowed by serial pQCT scans in 10/10 healthy men and women aged 20–40years. Indicators of cortical mass (mineral content -BMC-, cross-sectional area -CSA-), mineralization (volumetric BMD, vBMD), design (perimeters, thickness, moments of inertia -MIs-) and strength (Bone Strength Indices, BSIs; polar Strength-Strain Index, pSSI) were determined. All cross-sectional shapes and geometrical or strength indicators suggested a sequence of five different regions along the bone, which would be successively adapted to 1. transmit loads from the articular surface to the cortical shell (near the proximal tibia-fibular joint), 2. favor lateral bending (central part of upper half), 3. resist lateral bending (mid-diaphysis), 4. favor lateral bending again (central part of the lower half), and 5. resist bending/torsion (distal end). Cortical BMC and the cortical/total CSA ratio were higher at the midshaft than at both bone ends (p<0.001). However, all MIs, BSIs and pSSI values and the endocortical perimeter/cortical CSA ratio (indicator of the mechanostat's ability to re-distribute the available cortical mass) showed a “W-shaped” distribution along the bone, with maximums at the mid-shaft and at both bone's ends (site effect, p<0.001). The correlation coefficient (r) of the relationship between MIs (y) and cortical vBMD (x) at each bone site (“distribution/quality” curve that describes the efficiency of distribution of the cortical tissue as a function of the local tissue stiffness) was higher at proximal than distal bone regions (p<0.001). The results from the study suggest that human fibula is primarily adapted to resist bending and torsion rather than compression stresses, and that fibula's bending strength is lower at the center of its proximal and distal halves and higher at the mid-shaft and at both bone's ends. This would favor, proximally, the elastic absorption of energy by the attached muscles that rotate or evert the foot, and distally, the widening of the heel joint and the resistance to excessive lateral bending. Results also suggest that biomechanical control of structural stiffness differs between proximal and distal fibula.

Comparison of Tibial Strength Between Adult Female Dancers, Gymnasts, and Runners

The magnitude, frequency, and patterns of mechanical loading are important factors in how weight-bearing bones adapt their strength. Overall, adolescent and adult female athletes that participate in high impact physical activity have greater gains in bone strength than athletes that participate in low-repetitive impact activities (Nichols et al., 2007, Uusi-Rasi et al., 2006, and Nikander et al., 2010); however, it is not clear how medium impact activities (dance) compare to high impact activities (gymnastics) and low-repetitive activities (running) with respect to their osteogenic effects at the tibia. PURPOSE: To compare tibial strength between female adult dancers, gymnasts, and runners. METHODS: Eleven eumenorrheic dance majors and eleven eumenorrheic collegiate gymnasts (ages 18–22) were recruited. Runner (n=22) and sedentary control (n=19) data were obtained from the University of Minnesota Laboratory of Musculoskeletal Health database (Smock et al., 2009 and Bruininks, 2009). Participants’ non-dominant tibias were scanned using peripheral quantitative computed tomography at two locations - 4% (metaphyseal) and 66% (diaphyseal) sites from the distal tibia endplate. The scans provided two estimates of bone strength; bone strength index (BSI; mg.mm-4/10,000) and polar strength-strain index (SSIp, mm3). BSI is an estimate of bone compressive strength at metaphyseal sites and SSIp is an estimate of bone’s ability to resist torsion at diaphyseal sites (Smock et. al. 2009; Farr et al. 2010). BSI at the 4% site and the SSIp at the 66% site were compared between groups using linear regression models. RESULTS: Participants did not differ in age, weight, or tibial length. After controlling for height and body mass, SSIp did not differ significantly between groups. Dancers, gymnasts and runners had significantly greater BSI (33.2%, 43.7% and 20%, respectively) than controls (p=0.001, p<0.001, and p=0.03, respectively). CONCLUSIONS: Despite differences in impact type, dance, gymnastics, and running appear to be effective at increasing distal tibia compressive strength - which is known to delay or prevent bone fragility later in life. Future studies should analyze the magnitude and frequency of loadings to further identify which activities provide the greatest osteogenic benefits in adult females.

Unique Effects of Energy versus Estrogen Deficiency on Components of Bone Strength in Exercising Women

Exercising women with menstrual disturbances are at risk for poor bone health due to hypoestrogenism. Energy deficiency often instigates menstrual dysfunction resulting in metabolic adaptations that independently threaten bone. Women experiencing both an energy and estrogen deficiency face an exacerbated risk to bone health. PURPOSE: To describe volumetric bone mineral density (vBMD), bone geometry, and estimated bone strength in exercising women (n=50) grouped by energy status (energy replete (EnR: n=25); energy deficient (EnD: n=25)) and estrogen status (estrogen replete (E2R: n=24); estrogen deficient (E2D: n=26)) resulting in four groups: EnR+E2R (n=12), EnR+E2D (n=13), EnD+E2R (n=12), EnD+E2D (n=13). METHODS: Energy status was defined by the ratio of measured to predicted resting energy expenditure (mREE/pREE). Estrogen status was defined by self-reported menstrual status and confirmed by assessment of urinary metabolites of reproductive hormones over one menstrual cycle or 28 day monitoring period. Peripheral quantitative computed tomography assessed vBMD, bone geometry, and estimated bone strength at the radius and tibia. RESULTS: The groups were similar in age (21 ± 0.4 years), gynecological age (8 ± 0.5 years), height (165.7 ± 0.9 cm), and weight (57.7 ± 1.2 kg). At the proximal tibia, EnD women exhibited significantly lower total vBMD, cortical area, and cortical thickness and greater endosteal circumference than EnR women (p≤0.020). E2D women exhibited significantly lower total and cortical vBMD and bone strength index (BSI) and greater total and trabecular area (p≤0.040) at the distal radius and lower cortical vBMD and thickness (p≤0.019) at the proximal radius compared to E2R women. EnD+E2D women had significantly lower total and trabecular vBMD at the distal tibia and radius and total vBMD and cortical thickness at the proximal tibia compared to EnR+E2D women (p≤0.048). CONCLUSION: Energy versus estrogen status affected bone differently and effects were site-specific. Women with both an energy and estrogen deficiency experienced the most adverse bone adaptations. Treating energy deficiency in exercising women may improve reproductive health, in turn addressing the unique contributions of energy status versus estrogen status to bone health. Supported by US DoD (PR054531).

Site-specific, adult bone benefits attributed to loading during youth: A preliminary longitudinal analysis

We examined site-specific bone development in relation to childhood and adolescent artistic gymnastics exposure, comparing up to 10years of prospectively acquired longitudinal data in 44 subjects, including 31 non-gymnasts (NON) and 13 gymnasts (GYM) who participated in gymnastics from pre-menarche to ≥1.9years post-menarche. Subjects underwent annual regional and whole-body DXA scans; indices of bone geometry and strength were calculated. Anthropometrics, physical activity, and maturity were assessed annually, coincident with DXA scans. Non-linear mixed effect models centered growth in bone outcomes at menarche and adjusted for menarcheal age, height, and non-bone fat-free mass to evaluate GYM-NON differences. A POST-QUIT variable assessed the withdrawal effect of quitting gymnastics. Curves for bone area, mass (BMC), and strength indices were higher in GYM than NON at both distal radius metaphysis and diaphysis (p<0.0001). At the femoral neck, greater GYM BMC (p<0.01), narrower GYM endosteal diameter (p<0.02), and similar periosteal width (p=0.09) yielded GYM advantages in narrow neck cortical thickness and buckling ratio (both p<0.001; lower BR indicates lower fracture risk). Lumbar spine and sub-head BMC were greater in GYM than NON (p<0.036). Following gymnastics cessation, GYM slopes increased for distal radius diaphysis parameters (p≤0.01) and for narrow neck BR (p=0.02). At the distal radius metaphysis, GYM BMC and compressive strength slopes decreased, as did slopes for lumbar spine BMC, femoral neck BMC, and narrow neck cortical thickness (p<0.02). In conclusion, advantages in bone mass, geometry, and strength at multiple skeletal sites were noted across growth and into young adulthood in girls who participated in gymnastics loading to at least 1.9years post-menarche. Following gymnastics cessation, advantages at cortical bone sites improved or stabilized, while advantages at corticocancellous sites stabilized or diminished. Additional longitudinal observation is necessary to determine whether residual loading benefits enhance lifelong skeletal strength.

Bone structure of adolescent swimmers; a peripheral quantitative computed tomography (pQCT) study.

The aims of the present study were: (1) to characterize vBMD, bone structure and strength with peripheral quantitative computerized tomography (pQCT) in adolescent swimmers and compare it to normo-active controls (CG); and (2) to evaluate the possible interaction that weight-bearing sports might have on swimmers bone. Cross-sectional. The non-dominant radius and tibia of 79 (32 females) swimmers and 49 (22 females) CG (both 11-18 years old) were evaluated at proximal and distal sites with a pQCT scanner. Values of total, trabecular and cortical volumetric bone mineral density (vBMD) were obtained from each scan. Cortical thickness, endosteal and periosteal circumferences were also measured and bone strength indexes were calculated. Analyses of covariance were used to compare variables between groups adjusting for age, tanner stage and bone length. Three different analyses were performed according to present and past sport participation in addition to swimming in order to determine differences among swimmers who had performed or were performing other sports (OTHER-SP) (10 females/17 males) and swimmers who had not performed other sports (NO-OTHER-SP) (22 females/22 males). Both of these groups were compared to each other and to a CG (22 females/27 males). No differences were found between swimmers and CG for bone strength indexes, structure or vBMD (independently of the compared sample). These results indicate that swimmers present similar bone strength and structure than CG who did not present high physical activity levels.

Are bone turnover markers associated with volumetric bone density, size, and strength in older men and women? The AGES-Reykjavik study.

Association between serum bone formation and resorption markers and bone mineral, structural, and strength variables derived from quantitative computed tomography (QCT) in a population-based cohort of 1745 older adults was assessed. The association was weak for lumbar spine and femoral neck areal and volumetric bone mineral density. The aim of this study was to examine the relationship between levels of bone turnover markers (BTMs; osteocalcin (OC), C-terminal cross-linking telopeptide of type I collagen (CTX), and procollagen type 1N propeptide (P1NP)) and quantitative computed tomography (QCT)-derived bone density, geometry, and strength indices in the lumbar spine and femoral neck (FN). A total of 1745 older individuals (773 men and 972 women, aged 66-92years) from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik cohort were studied. QCT was performed in the lumbar spine and hip to estimate volumetric trabecular, cortical, and integral bone mineral density (BMD), areal BMD, bone geometry, and bone strength indices. Association between BTMs and QCT variables were explored using multivariable linear regression. Major findings showed that all BMD measures, FN cortical index, and compressive strength had a low negative correlation with the BTM levels in both men and women. Correlations between BTMs and bone size parameters were minimal or not significant. No associations were found between BTMs and vertebral cross-sectional area in women. BTMs alone accounted for only a relatively small percentage of the bone parameter variance (1-10%). Serum CTX, OC, and P1NP were weakly correlated with lumbar spine and FN areal and volumetric BMD and strength measures. Most of the bone size indices were not associated with BTMs; thus, the selected bone remodeling markers do not reflect periosteal bone formation. These results confirmed the limited ability of the most sensitive established BTMs to predict bone structural integrity in older adults.

Does the frequency and intensity of physical activity in adolescence have an impact on bone? The Tromsø Study, Fit Futures.

BackgroundOptimization of the genetic potential for bone accrual in early life may prevent future fractures. Possible modification factors include lifestyle factors such as nutrition and physical activity. Measured levels of bone mineral density (BMD) and bone mass content (BMC) are indicators of bone strength, and are correlated with fracture risk. This study explored the impact of self-reported physical activity frequencies and intensity on BMD and BMC in Norwegian adolescents.MethodsIn 2010–2011 school students in two North-Norwegian municipalities were invited to a health survey, the Fit Future study. 508 girls and 530 boys aged 15–18 years attended. BMD and BMC were measured by dual X-ray absorptiometry. Physical activity and other lifestyle-factors were reported by questionnaires and clinical interviews. Statistical analyses were performed sex stratified, using ANOVA for comparison of means and linear regression models adjusting for factors known to affect bone.ResultsApproximately 2/3 of girls and boys reported themselves as physically active outside school hours. Active participants had a significantly higher BMD and BMC at all sites (p < 0.001), except for BMC total body in girls, compared to inactive participants. In multiple linear regression analyses, increased physical activity measured as days a week, categorized into seldom, moderate and highly, was positively associated with BMD (g/cm2) at all sites in girls. Girls reporting themselves as highly active had BMD levels 0.093 g/cm2, 0.090 g/cm2 and 0.046 g/cm2 higher (p < 0.001) than their more seldom active peers at femoral neck, total hip and total body respectively. Corresponding values for boys were 0.125 g/cm2, 0.133 g/cm2 and 0.66 g/cm2. BMC measures showed similar trends at femoral neck and total hip.ConclusionsIncreased level of physical activity is associated with higher BMD and BMC levels in adolescents. For both sexes high activity frequency seems to be essential, whilst boys reporting quite hard intensity has an additional impact. The differential effects of physical activity on bone strength in adolescence have clinical implications, especially in preventive strategies.

Muscle Power Predicts Adolescent Bone Strength: Iowa Bone Development Study.

To assess association between lower body muscle power and bone strength as well as the mediating effect of muscle cross-sectional area (MCSA) on that association. Participants (141 males and 162 females) were approximately 17 yr. Muscle power was predicted using vertical jump and the Sayers equation. Using peripheral quantitative computed tomography (pQCT), bone strength indices were obtained at two locations of the tibia, corresponding to primary stressors acting upon each site: bone strength index for compression (BSI) at the distal 4% site; density-weighted polar section modulus strength-strain index (SSIp) and cortical bone area (CoA) at the 66% midshaft site for torsion. Muscle cross-sectional area was measured at the 66% site. Pearson bivariate and partial correlation coefficients were estimated to quantify the strength of the associations among variables. Direct and indirect mediation model effects were estimated, and 95% bootstrap confidence intervals were constructed to test the causal hypothesis. Height and maturity were examined as covariates. Pearson correlation coefficients among muscle power, MCSA, and bone strength were statistically significant (P < 0.01) and ranged from r = 0.54 to r = 0.78. After adjustment for covariates, associations were reduced (r = 0.37 to 0.69) (P < 0.01). Mediation models for males for BSI, SSIp, and CoA accounted for 38%, 66%, and 54% of the variance in bone strength, respectively. Models for females for BSI, SSIp, and CoA accounted for 46%, 77%, and 66% of the variance, respectively. We found strong and consistent associations as well as direct and indirect pathways, among muscle power, MCSA, and tibia strength. These results support the use of muscle power as a component of health-related fitness in bone health interventions for older adolescents.

Chronic effects of stroke on hip bone density and tibial morphology: a longitudinal study.

The study aimed to quantify the long-term effects of stroke on tibial bone morphology and hip bone density. Only the trabecular bone mineral density and bone strength index in the hemiparetic tibial distal epiphysis showed a significant decline among individuals who had sustained a stroke 12-24months ago. This study aims to determine the changes in bone density and morphology in lower limb long bones during a 1-year follow-up period and their relationship to muscle function in chronic stroke patients. Twenty-eight chronic stroke patients (12-166months after the acute stroke event at initial assessment) and 27 controls underwent bilateral scanning of the hip and tibia using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, respectively. Each subject was re-assessed 1year after the initial assessment. Twenty stroke cases and 23 controls completed all assessments. At the end of the follow-up, the paretic tibial distal epiphysis suffered significant decline in trabecular bone density (-1.8 ± 0.6%, p = 0.006) and bone strength index (-2.7 ± 0.6%, p < 0.001). More severe decline in the former was associated with poorer leg muscle strength (ρ = 0.447, p = 0.048) and motor recovery (ρ = 0.489, p = 0.029) measured at initial assessment. The loss in trabecular bone density remained significant among those whose stroke onset was 12-24months ago (p < 0.001), but not among those whose stroke onset was beyond 24months ago (p > 0.05) at the time of initial assessment. The changes of outcomes in the tibial diaphysis, except for cortical bone mineral content on the non-paretic side (-1.3 ± 0.3%, p = 0.003), and hip bone density were well within the margin of error for precision. There is evidence of continuous trabecular bone loss in the paretic tibial distal epiphysis among chronic stroke patients, but it tends to plateau after 2years of stroke onset. The steady state may have been reached earlier in the hip and tibial diaphysis.

Cystic fibrosis-related bone disease in children: Examination of peripheral quantitative computed tomography (pQCT) data

BackgroundThe investigation of skeletal health data beyond dual X-ray absorptiometry (DXA) is limited in young individuals with CF. We assessed volumetric bone mineral densities (BMD), and bone and muscle parameters using peripheral quantitative computed tomography (pQCT) in individuals with CF and controls, 7.00–17.99years. MethodsPeripheral QCT (XCT 3000, Stratec) measurements were made in 53 individuals with CF and 53 controls. Bone mineral content (BMC), total volumetric BMD (vBMD) and cross sectional area (CSA) of the bone were measured at the 4% and 66% sites of the non-dominant tibia and radius. Additionally, trabecular vBMD and bone strength index (BSIc) were measured at the 4% sites, and cortical vBMD, muscle CSA (mCSA) and strength strain index (SSI) were measured at the 66% sites. ResultsPre-pubertal males with CF had greater trabecular vBMD (p=0.01) and total vBMD (p=0.00) at 4% tibia, and greater total vBMD (p=0.02) at 4% radius. Pre-pubertal females with CF had greater total vBMD at 66% tibia (p=0.02) and radius (p=0.04), and cortical vBMD (p=0.04) at the radius. At puberty, the CF cohort had less BMC at 4% tibia (males, p=0.02; females, p=0.01), and smaller mCSA at 66% tibia (males, p=0.02; females, p=0.01). Pubertal CF females had a smaller bone CSA (p=0.01) at 4% tibia, and lower bone strength (SSI) at the tibia (p=0.00) and radius (p=0.05) sites. ConclusionsBone strength parameters were not compromised prior to puberty in this CF cohort. At puberty, the bone phenotype changed for this CF cohort, showing several deficits compared to the controls. However, bone strength was adapting to the mechanical demands of the muscle. Altered bone parameters and their implications for lowered bone strength with increased age may be greatly influenced by: the CF cohort remaining smaller for age and/or a reduced bone strain, secondary to reduced muscle force.

Effect of dexamethasone on mandibular bone biomechanics in rats during the growth phase as assessed by bending test and peripheral quantitative computerized tomography.

Long-term glucocorticoid administration to growing rats induces osteopenia and alterations in the biomechanical behavior of the bone. This study was performed to estimate the effects of dexamethasone (DTX), a synthetic steroid with predominant glucocorticoid activity, on the biomechanical properties of the mandible of rats during the growth phase, as assessed by bending test and peripheral quantitative computed tomographic (pQCT) analysis. The data obtained by the two methods will provide more precise information when analyzed together than separately. Female rats aged 23 d (n=7) received 500μg.kg-1 per day of DXT for 4 weeks. At the end of the treatment period, their body weight and body length were 51.3% and 20.6% lower, respectively, than controls. Hemimandible weight and area (an index of mandibular size) were 27.3% and 9.7% lower, respectively. The right hemimandible of each animal was subjected to a mechanical 3-point bending test. Significant weakening of the bone, as shown by a correlative impairment of strength and stiffness, was observed in experimental rats. Bone density and cross-sectional area were measured by pQCT. Cross-sectional, cortical and trabecular areas were reduced by 20% to 30% in the DTX group, as were other cortical parameters, including the bone density, mineral content and cross-sectional moment of inertia. The "bone strength index" (BSI, the product of the pQCT-assessed xCSMI and vCtBMD) was 56% lower in treated rats, which compares well with the 54% and 52% reduction observed in mandibular strength and stiffness determined through the bending test. Data suggest that the corticosteroid exerts a combined, negative action on bone geometry (mass and architecture) and volumetric bone mineral density of cortical bone, which would express independent effects on both cellular (material quality) and tissue (cross-sectional design) levels of biological organization of the skeleton in the species.

Adolescence physical activity is associated with higher tibial pQCT bone values in adulthood after 28-years of follow-up — The Cardiovascular Risk in Young Finns Study

High peak bone mass and strong bone phenotype are known to be partly explained by physical activity during growth but there are few prospective studies on this topic. In this 28-year follow-up of Cardiovascular Risk in Young Finns Study cohort, we assessed whether habitual childhood and adolescence physical activity or inactivity at the age of 3–18years were associated with adult phenotype of weight-bearing tibia and the risk of low-energy fractures. Baseline physical activity and data on clinical, nutritional and lifestyle factors were assessed separately for females and males aged 3–6-years (N=395–421) and 9–18-years (N=923–965). At the age of 31–46-years, the prevalence of low-energy fractures was assessed with a questionnaire and several tibial traits were measured with pQCT (bone mineral content (BMC; mg), total and cortical cross-sectional areas (mm2), trabecular (for the distal site only) and cortical (for the shaft only) bone densities (mg/cm3), stress–strain index (SSI; mm3, for the shaft only), bone strength index (BSI; mg2/cm4, for the distal site only) and the cortical strength index (CSI, for the shaft only)). For the statistical analysis, each bone trait was categorized as below the cohort median or the median and above and the adjusted odds ratios (OR) were determined. In females, frequent physical activity at the age of 9–18-years was associated with higher adulthood values of BSI, total and cortical areas, BMC, CSI and SSI at the tibia independently of many health and lifestyle factors (ORs 0.33–0.53, P≤0.05; P-values for trend 0.002–0.05). Cortical density at the tibial shaft showed the opposite trend (P-value for trend 0.03). Similarly in males, frequent physical activity was associated with higher values of adult total and cortical areas and CSI at the tibia (ORs 0.48–0.53, P≤0.05; P-values for trend 0.01–0.02). However, there was no evidence that childhood or adolescence physical activity was associated with lower risk of low energy fractures during the follow-up. In conclusion, frequent habitual physical activity in adolescence seems to confer benefits on tibial bone size and geometry in adulthood.

Does playing surfaces influence the bone geometry and strength indexes in young male soccer players?

Does playing surfaces influence the bone geometry and strength indexes in young male soccer players?

The muscle–bone interaction in Turner syndrome

ObjectivesTurner syndrome (TS) is associated with an increased fracture rate due to reduced bone strength, which is mainly determined by skeletal muscle force. This study aimed to assess the muscle force–bone strength relationship in TS and to compare it with that of healthy controls. MethodsThis study included 39 girls with TS and 67 healthy control girls. Maximum muscle force (Fmax) was assessed through multiple one-legged hopping with jumping mechanography. Peripheral quantitative computerized tomography assessed the bone strength index at the tibial metaphysis (BSI 4) and the polar strength–strain index at the diaphysis (SSI polar 66). The effect of TS on the muscle–bone unit was tested using multiple linear regression. ResultsTS had no impact on Fmax (p=0.14); however, a negative effect on bone strength (p<0.001 for BSI 4 and p<0.01 for SSI polar 66) was observed compared with healthy controls. Bone strength was lower in the TS group (by 18%, p<0.01, for BSI 4 and by 7%, p=0.027, for SSI polar 66), even after correcting for Fmax. ConclusionsSimilar muscle force induces lower bone strength in TS compared with healthy controls, which suggests altered bone-loading sensitivity in TS.

Morphological and bone strength indices in girls with adolescent idiopathic scoliosis and their correlations with leptin and soluble leptin receptor

Results Compared with controls, AIS subjects had higher sOB-R level (p=0.006), higher SMI value (p=0.020) reflecting more rod-like structures within the trabecular compartment, and numerically lower stiffness (-2.03%) and estimated failure load (-3.07%). Significant negative correlation was found between SMI and serum total leptin level in AIS (r=-0.325; p=0.003) but not in controls (p=0.533). Significant positive correlations were found between stiffness, estimated failure load, and serum total leptin in both AIS (r=0.278, p=0.003; r=0.268, p=0.004 respectively) and controls (r=0.462, p<0.001; r=0.468, p<0.001 respectively). Conclusion

Adult bone strength of children from single-parent families: the Midlife in the United States Study.

Bone health may be negatively impacted by childhood socio-environmental circumstances. We examined the independent associations of single-parent childhood and parental death or divorce in childhood with adult bone strength indices. Longer exposure to a single-parent household in childhood was associated with lower bone strength in adulthood. Because peak bone mass is acquired during childhood, bone health may be negatively impacted by childhood socio-environmental disadvantage. The goal of this study was to determine whether being raised in a single-parent household is associated with lower bone strength in adulthood. Using dual-energy X-ray absorptiometry data from 708 participants (mean age 57 years) in the Midlife in the United States Biomarker Project, we examined the independent associations of composite indices of femoral neck bone strength relative to load (in three failure modes: compression, bending, and impact) in adulthood with the experience of single-parent childhood and parental death or divorce in childhood. After adjustment for gender, race, menopause transition stage, age, and body mass index, each additional year of single-parent childhood was associated with 0.02 to 0.03 SD lower indices of adult femoral neck strength. In those with 9-16 years of single-parent childhood, the compression strength index was 0.41 SD lower, bending strength index was 0.31 SD lower, and impact strength index was 0.25 SD lower (all p values < 0.05). In contrast, parental death or divorce during childhood was not by itself independently associated with adult bone strength indices. The magnitudes of these associations were unaltered by additional adjustment for lifestyle factors and socioeconomic status in childhood and adulthood. Independent of parental death or divorce, growing up in a single-parent household is associated with lower femoral neck bone strength in adulthood, and this association is not entirely explained by childhood or adult socioeconomic conditions or lifestyle choices.

The Influence of Organized Physical Activity (Including Gymnastics) on Young Adult Skeletal Traits: Is Maturity Phase Important?

We prospectively evaluated adolescent organized physical activity (PA) as a factor in adult female bone traits. Annual DXA scans accompanied semiannual records of anthropometry, maturity, and PA for 42 participants in this preliminary analysis (criteria: appropriately timed DXA scans at ~1 year premenarche [predictor] and ~5 years postmenarche [dependent variable]). Regression analysis evaluated total adolescent interscan PA and PA over 3 maturity subphases as predictors of young adult bone outcomes: 1) bone mineral content (BMC), geometry, and strength indices at nondominant distal radius and femoral neck; 2) subhead BMC; 3) lumbar spine BMC. Analyses accounted for baseline gynecological age (years pre- or postmenarche), baseline bone status, adult body size and interscan body size change. Gymnastics training was evaluated as a potentially independent predictor, but did not improve models for any outcomes (p > .07). Premenarcheal bone traits were strong predictors of most adult outcomes (semipartial r2 = .21-0.59, p ≤ .001). Adult 1/3 radius and subhead BMC were predicted by both total PA and PA 1-3 years postmenarche (p < .03). PA 3-5 years postmenarche predicted femoral narrow neck width, endosteal diameter, and buckling ratio (p < .05). Thus, participation in organized physical activity programs throughout middle and high school may reduce lifetime fracture risk in females.

Heel bone strength is related to lifestyle factors in Okinawan men with type 2 diabetes mellitus.

Aims/IntroductionAlthough male diabetic patients have an increased risk of fracture, there is little information about this in the literature. The association between heel bone stiffness and the lifestyle of male patients with diabetes was evaluated.Materials and MethodsThe study included 108 participants with type 2 diabetes mellitus patients and 168 age-adjusted, healthy male volunteers. None of the participants had a history of osteoporosis or other severe diseases. Heel bone stiffness was examined by quantitative ultrasound, and each participant completed a health interview survey questionnaire. Bone stiffness was taken as an indicator of bone strength. Stepwise regression analysis was used to investigate associations between bone stiffness and lifestyle-related factors, such as sunlight exposure, intake of milk or small fish, regular exercise, cigarette smoking, consumption of alcohol, and number of remaining teeth.ResultsBone stiffness showed a significant negative association with cigarette smoking [standardized coefficient (SC) = −0.297, F-value (F) = 10.059] and age (SC = −0.207, F = 7.565) in diabetic patients. Bone stiffness showed a significant negative association with age (SC = −0.371, F = 12.076) and height (SC = −0.193, F = 7.898), as well as a significant positive association with sunlight exposure (SC = 0.182, F = 9.589) and intake of small fish (SC = 0.170, F = 7.393) in controls.ConclusionsThese findings suggest that cigarette smoking and age are negatively associated with bone stiffness in Okinawan male patients with type 2 diabetes mellitus.

Exercise characteristics influence femoral cross-sectional geometry: a magnetic resonance imaging study in elite female athletes.

The associations between mid-femoral cross-sectional geometry and exercise characteristics were investigated in female athletes. The effects on bone geometry for weight-bearing sports with low-to-high-impact were greater than those for non-impact weight-bearing sports, whereas low-impact or high-strain-magnitude/low-strain-rate sports had less of an effect on bone geometry compared with higher-impact sports. Many previous studies have investigated tibial geometry in athletes; however, few studies have examined the associations between femoral cross-sectional geometry and exercise characteristics. The aim of this study was to investigate these relationships using magnetic resonance imaging (MRI) at the femoral mid-shaft. One hundred and fifty-three female elite athletes, aged 18-34 years, were classified into five groups based on the characteristics of their sports. Sports were considered non-impact (n = 27), low- or moderate-impact (n = 39), odd-impact (n = 38), high-strain-magnitude/low-strain-rate (n = 10), or high-impact (n = 39). Bone geometrical parameters, including cortical area, periosteal perimeter, and moment of inertia (bone strength index), were determined using MRI images. Higher-impact groups displayed bone expansion, with significantly greater periosteal perimeters, cortical areas (~37.3%), and minimum moments of inertia (I(min,) ~92.3%) at the mid-femur than non- and low-impact groups. After adjusting for age, height, and weight, the cortical area and I(min) of the low-impact and high-strain-magnitude/low-strain-rate groups were also significantly greater than those of the non-impact group. Higher-impact sports with high strain rates stimulated periosteal bone formation and improved bone geometry and strength indices at the femoral mid-shaft. Although our results indicate that weight-bearing sports are beneficial even if they are low impact, the effects of lower-impact or high-strain-magnitude/low-strain-rate sports on bone geometry were less pronounced than the effects of higher-impact sports at the femoral mid-shaft.

Geometric indices of hip bone strength in male professional soccer players.

The aim of this study was to compare geometric indices of hip bone strength in male professional soccer players and controls. Twenty-three male professional soccer players and 21 male sedentary subjects whose ages range between 18 and 30 years participated in this study. Weight and height were measured, and body mass index (BMI) was calculated. Daily calcium intake and physical activity were evaluated using validated questionnaires. Hip bone mineral density was measured by dual-energy X-ray absorptiometry (DXA). To evaluate hip bone geometry, DXA scans were analyzed at the narrow-neck (NN), the intertrochanteric (IT) region and the femoral shaft (FS) by the Hip Structure Analysis (HSA) program. Cross sectional area (CSA), an index of axial compression strength, cross sectional moment of inertia (CSMI), an index of structural rigidity, section modulus (Z), an index of bending strength, cortical thickness (CT) and buckling ratio (BR) were measured from bone mass profiles. CSA, CSMI, Z and CT of the three regions (NN, IT and FS) were higher in soccer players compared to controls. After adjustment for either age, body weight, height or physical activity duration (h/week), CSA, CSMI, Z and CT of the three regions remained higher in soccer players compared to controls. This study suggests that, in young adult males, soccer practice is associated with greater axial strength, bending strength and structural rigidity indices at the hip.