Physical activity is the strongest predictor of calcaneal peak bone mass in young Swedish men

Genomic imputation of ancient Asian populations contrasts local adaptation in pre- and post-agricultural Japan

Early modern humans lived as hunter-gatherers for millennia before agriculture, yet the genetic adaptations of these populations remain a mystery. Here, we investigate selection in the ancient hunter-gatherer-fisher Jomon and contrast pre- and post-agricultural adaptation in the Japanese archipelago. Building on the successful validation of imputation with ancient Asian genomes, we identify selection signatures in the Jomon, particularly robust signals from KITLG variants, which may have influenced dark pigmentation evolution. The Jomon lacks well-known adaptive variants (EDAR, ADH1B, and ALDH2), marking their emergence after the advent of farming in the archipelago. Notably, the EDAR and ADH1B variants were prevalent in the archipelago 1,300 years ago, whereas the ALDH2 variant could have emerged later due to its absence in other ancient genomes. Overall, our study underpins local adaptation unique to the Jomon population, which in turn sheds light on post-farming selection that continues to shape contemporary Asian populations.

Trabecular bone morphology in big cats reflects the complex diversity of limb use but not home range size or daily travel distance

A relationship exists between mechanical loading and bone morphology. Although studies show a relationship between trabecular bone morphology and locomotor strategy in mammals, none of them have studied trabecular bone morphology in felid species occupying disparate and overlapping habitats. We investigate trabecular bone volume fraction (BVF) in the femoral and humeral heads, and distal tibia of four felid species (mountain lions, jaguars, cheetahs, and leopards) to identify whether there is a relationship between BVF and locomotor behavior. This study's goals are to identify whether felid species with high daily travel distance or large home range size have greater BVF compared with those with small daily travel distance or home range size, and whether BVF is correlated among the three elements of the fore and hindlimb studied. We quantified BVF in micro- and peripheral computed tomography images and found no significant differences across species in the femoral and humeral head (p > 0.05). However, in the distal tibia, results showed that leopards, mountain lions, and cheetahs have significantly greater (p < 0.05) BVF than jaguars. Despite differences in home range size and daily travel distance, the proximal elements did not reflect differences in BVF; however, the distal-most element did, suggesting decreased loading among jaguars. These findings suggest that the observed pattern of trabecular bone morphology is potentially due to the diversity in locomotor strategy of the forelimb. Additionally, these results imply that neither home range size nor daily travel distance are clear indicators of activity levels. A cautious approach is warranted in studying how loading influences trabecular morphology.

Effects of reduced mobility on trabecular bone density in captive big cats

Bone responds to elevated mechanical loading by increasing in mass and density. Therefore, wild animals should exhibit greater skeletal mass and density than captive conspecifics. This expectation is pertinent to testing bone functional adaptation theories and to comparative studies, which commonly use skeletal remains that combine zoo and wild-caught specimens. Conservationists are also interested in the effects of captivity on bone morphology as it may influence rewilding success. We compared trabecular bone volume fraction (BVF) between wild and captive mountain lions, cheetahs, leopards and jaguars. We found significantly greater BVF in wild than in captive felids. Effects of captivity were more marked in the humerus than in the femur. A ratio of humeral/femoral BVF was also lower in captive animals and showed a positive relationship to home range size in wild animals. Results are consistent with greater forelimb than hindlimb loading during terrestrial travel, and possibly reduced loading of the forelimb associated with lack of predatory behaviour in captive animals. Thus, captivity among felids has general effects on BVF in the postcranial skeleton and location-specific effects related to limb use. Caution should be exercised when identifying skeletal specimens for use in comparative studies and when rearing animals for conservation purposes.

Ontogenetic changes to metacarpal trabecular bone structure in mountain and western lowland gorillas

The trabecular bone morphology of adult extant primates has been shown to reflect mechanical loading related to locomotion. However, ontogenetic studies of humans and other mammals suggest an adaptive lag between trabecular bone response and current mechanical loading patterns that could result in adult trabecular bone morphology reflecting juvenile behaviours. This study investigates ontogenetic changes in the trabecular bone structure of the third metacarpal of mountain gorillas (Gorilla beringei beringei; n = 26) and western lowland gorillas (Gorilla gorilla gorilla; n = 26) and its relationship to expected changes in locomotor loading patterns. Results show that trabecular bone reflects predicted mechanical loading throughout ontogeny. Bone volume fraction, trabecular thickness and trabecular number are low at birth and increase with age, although degree of anisotropy remains relatively stable throughout ontogeny. A high concentration of bone volume fraction can be observed in the distopalmar region of the third metacarpal epiphysis in early ontogeny, consistent with the high frequency of climbing, suspensory and other grasping behaviours in young gorillas. High trabecular bone concentration increases dorsally in the epiphysis during the juvenile period as terrestrial knuckle-walking becomes the primary form of locomotion. However, fusion of the epiphysis does not take place until 10-11 years of age, and overall trabecular structure does not fully reflect the adult pattern until 12 years of age, indicating a lag between adult-like behaviours and adult-like trabecular morphology. We found minimal differences in trabecular ontogeny between mountain and western lowland gorillas, despite presumed variation in the frequencies of arboreal locomotor behaviours. Altogether, ontogenetic changes in Gorilla metacarpal trabecular structure reflect overall genus-level changes in locomotor behaviours throughout development, but with some ontogenetic lag that should be considered when drawing functional conclusions from bone structure in extant or fossil adolescent specimens.

Cortical and trabecular bone structure of the hominoid capitate

Morphological variation in the hominoid capitate has been linked to differences in habitual locomotor activity due to its importance in movement and load transfer at the midcarpal joint proximally and carpometacarpal joints distally. Although the shape of bones and their articulations are linked to joint mobility, the internal structure of bones has been shown experimentally to reflect, at least in part, the loading direction and magnitude experienced by the bone. To date, it is uncertain whether locomotor differences among hominoids are reflected in the bone microarchitecture of the capitate. Here, we apply a whole‐bone methodology to quantify the cortical and trabecular architecture (separately and combined) of the capitate across bipedal (modern Homo sapiens), knuckle‐walking (Pan paniscus, Pan troglodytes, Gorilla sp.), and suspensory (Pongo sp.) hominoids (n = 69). It is hypothesized that variation in bone microarchitecture will differentiate these locomotor groups, reflecting differences in habitual postures and presumed loading force and direction. Additionally, it is hypothesized that trabecular and cortical architecture in the proximal and distal regions, as a result of being part of mechanically divergent joints proximally and distally, will differ across these portions of the capitate. Results indicate that the capitate of knuckle‐walking and suspensory hominoids is differentiated from bipedal Homo primarily by significantly thicker distal cortical bone. Knuckle‐walking taxa are further differentiated from suspensory and bipedal taxa by more isotropic trabeculae in the proximal capitate. An allometric analysis indicates that size is not a significant determinate of bone variation across hominoids, although sexual dimorphism may influence some parameters within Gorilla. Results suggest that internal trabecular and cortical bone is subjected to different forces and functional adaptation responses across the capitate (and possibly other short bones). Additionally, while separating trabecular and cortical bone is normal protocol of current whole‐bone methodologies, this study shows that when applied to carpals, removing or studying the cortical bone separately potentially obfuscates functionally relevant signals in bone structure.

Genetic contributions to variation in human stature in prehistoric Europe

Measurements of prehistoric human skeletal remains provide a record of changes in height and other anthropometric traits over time. Often, these changes are interpreted in terms of plastic developmental response to shifts in diet, climate, or other environmental factors. These changes can also be genetic in origin, but, until recently, it has been impossible to separate the effects of genetics and environment. Here, we use ancient DNA to directly estimate genetic changes in phenotypes and to identify changes driven not by genetics, but by environment. We show that changes over the past 35,000 y are largely predicted by genetics but also identify specific shifts that are more likely to be environmentally driven.

The relative contributions of genetics and environment to temporal and geographic variation in human height remain largely unknown. Ancient DNA has identified changes in genetic ancestry over time, but it is not clear whether those changes in ancestry are associated with changes in height. Here, we directly test whether changes over the past 38,000 y in European height predicted using DNA from 1,071 ancient individuals are consistent with changes observed in 1,159 skeletal remains from comparable populations. We show that the observed decrease in height between the Early Upper Paleolithic and the Mesolithic is qualitatively predicted by genetics. Similarly, both skeletal and genetic height remained constant between the Mesolithic and Neolithic and increased between the Neolithic and Bronze Age. Sitting height changes much less than standing height—consistent with genetic predictions—although genetics predicts a small post-Neolithic increase that is not observed in skeletal remains. Geographic variation in stature is also qualitatively consistent with genetic predictions, particularly with respect to latitude. Finally, we hypothesize that an observed decrease in genetic heel bone mineral density in the Neolithic reflects adaptation to the decreased mobility indicated by decreased femoral bending strength. This study provides a model for interpreting phenotypic changes predicted from ancient DNA and demonstrates how they can be combined with phenotypic measurements to understand the relative contribution of genetic and developmentally plastic responses to environmental change.

Effect of 7 Months of Physical Training and Military Routine on the Bone Mass of Young Adults

INTRODUCTION

Physical activity (PA) has a great influence on bone mineral density (BMD) and bone mineral content (BMC), however longitudinal studies that seek to relate bone mass to physical activity are scarce and have a small sample size. The aim of this study was to evaluate and compare the effect of 7 months of military physical training (MPT), impact sports (IS), and swimming in the bone mass of young military adults.

MATERIALS AND METHODS

A prospective study was conducted with 213 military school students (male and aged 19.2 ± 1.2 years) divided into three groups: MPT (n = 144), IS (n = 56), and Swimming (n = 13). Dual-energy X-ray absorptiometry was used to determine body composition (percentage of fat, fat mass, and fat-free mass) and bone mass (BMD, BMD Z-Score, total BMC, arm BMC, leg BMC, and trunk BMC), at the beginning of the military service and after 7 months of training.

RESULTS

It was observed a significant increase in BMD, BMD Z-Score, total BMC and BMC of all segments analyzed for all groups (p < 0.01). There was a significantly greater variation in BMD of the IS group in relation to the MPT group (p < 0.01), and in the arm BMC of the MPT group in relation to the IS group (p < 0.05).

CONCLUSION

After 7 months of training, there were significant increases in BMC and BMD of all the groups evaluated. The bone response was associated with the muscular group used in the physical exercise and the IS group showed greater gain in BMD.

The interactions of physical activity, exercise and genetics and their associations with bone mineral density: implications for injury risk in elite athletes

Low bone mineral density (BMD) is established as a primary predictor of osteoporotic risk and can also have substantial implications for athlete health and injury risk in the elite sporting environment. BMD is a highly multi-factorial phenotype influenced by diet, hormonal characteristics and physical activity. The interrelationships between such factors, and a strong genetic component, suggested to be around 50-85% at various anatomical sites, determine skeletal health throughout life. Genome-wide association studies and case-control designs have revealed many loci associated with variation in BMD. However, a number of the candidate genes identified at these loci have no known associated biological function or have yet to be replicated in subsequent investigations. Furthermore, few investigations have considered gene-environment interactions-in particular, whether specific genes may be sensitive to mechanical loading from physical activity and the outcome of such an interaction for BMD and potential injury risk. Therefore, this review considers the importance of physical activity on BMD, genetic associations with BMD and how subsequent investigation requires consideration of the interaction between these determinants. Future research using well-defined independent cohorts such as elite athletes, who experience much greater mechanical stress than most, to study such phenotypes, can provide a greater understanding of these factors as well as the biological underpinnings of such a physiologically "extreme" population. Subsequently, modification of training, exercise or rehabilitation programmes based on genetic characteristics could have substantial implications in both the sporting and public health domains once the fundamental research has been conducted successfully.

Changes in physical activity over the lifespan: impact on body composition and sarcopenic obesity

Physical activity and body composition show a typical pattern over the lifecycle. Fat-free mass and physical performance generally peak in early adulthood. Here, evidence for a relation between physical activity changes over the life span and the development of sarcopenic obesity is presented. Activity-induced energy expenditure increases with body size and physical activity during growth. The physical activity level, calculated by expressing total energy expenditure as a multiple of resting energy expenditure, gradually increases from early age to adulthood to decrease again in old age. Habitual physical activity has a significant effect on growth of fat-free mass during adolescence and thus on peak fat-free mass and physical performance in early adulthood. Older subjects have a lower fat-free mass and lower physical activity levels but there is no association, suggesting physical activity does not protect against loss of lean body mass at higher age. Prevention of sarcopenic obesity starts with a physically active lifestyle to develop a healthy peak fat-free mass and subsequent prevention of excess fat gain. The change from a physically active to a more sedentary routine in later life requires restriction of energy intake to maintain energy balance.

Cancellous bone and theropod dinosaur locomotion. Part I-an examination of cancellous bone architecture in the hindlimb bones of theropods

This paper is the first of a three-part series that investigates the architecture of cancellous ('spongy') bone in the main hindlimb bones of theropod dinosaurs, and uses cancellous bone architectural patterns to infer locomotor biomechanics in extinct non-avian species. Cancellous bone is widely known to be highly sensitive to its mechanical environment, and has previously been used to infer locomotor biomechanics in extinct tetrapod vertebrates, especially primates. Despite great promise, cancellous bone architecture has remained little utilized for investigating locomotion in many other extinct vertebrate groups, such as dinosaurs. Documentation and quantification of architectural patterns across a whole bone, and across multiple bones, can provide much information on cancellous bone architectural patterns and variation across species. Additionally, this also lends itself to analysis of the musculoskeletal biomechanical factors involved in a direct, mechanistic fashion. On this premise, computed tomographic and image analysis techniques were used to describe and analyse the three-dimensional architecture of cancellous bone in the main hindlimb bones of theropod dinosaurs for the first time. A comprehensive survey across many extant and extinct species is produced, identifying several patterns of similarity and contrast between groups. For instance, more stemward non-avian theropods (e.g. ceratosaurs and tyrannosaurids) exhibit cancellous bone architectures more comparable to that present in humans, whereas species more closely related to birds (e.g. paravians) exhibit architectural patterns bearing greater similarity to those of extant birds. Many of the observed patterns may be linked to particular aspects of locomotor biomechanics, such as the degree of hip or knee flexion during stance and gait. A further important observation is the abundance of markedly oblique trabeculae in the diaphyses of the femur and tibia of birds, which in large species produces spiralling patterns along the endosteal surface. Not only do these observations provide new insight into theropod anatomy and behaviour, they also provide the foundation for mechanistic testing of locomotor hypotheses via musculoskeletal biomechanical modelling.

Systemic patterns of trabecular bone across the human and chimpanzee skeleton

Aspects of trabecular bone architecture are thought to reflect regional loading of the skeleton, and thus differ between primate taxa with different locomotor and postural modes. However, there are several systemic factors that affect bone structure that could contribute to, or be the primary factor determining, interspecific differences in bone structure. These systemic factors include differences in genetic regulation, sensitivity to loading, hormone levels, diet, and activity levels. Improved understanding of inter-/intraspecific variability, and variability across the skeleton of an individual, is required to interpret properly potential functional signals present within trabecular structure. Using a whole-region method of analysis, we investigated trabecular structure throughout the skeleton of humans and chimpanzees. Trabecular bone volume fraction (BV/TV), degree of anisotropy (DA) and trabecular thickness (Tb.Th) were quantified from high resolution micro-computed tomographic scans of the humeral and femoral head, third metacarpal and third metatarsal head, distal tibia, talus and first thoracic vertebra. We found that BV/TV is, in most anatomical sites, significantly higher in chimpanzees than in humans, suggesting a systemic difference in trabecular structure unrelated to local loading regime. Differences in BV/TV between the forelimb and hindlimb did not clearly reflect differences in locomotor loading in the study taxa. There were no clear systemic differences between the taxa in DA and, as such, this parameter might reflect function and relate to differences in joint loading. This systemic approach reveals both the pattern of variability across the skeleton and between taxa, and helps identify those features of trabecular structure that may relate to joint function.

Trabecular and cortical bone structure of the talus and distal tibia in Pan and Homo

OBJECTIVES

Internal bone structure, both cortical and trabecular bone, remodels in response to loading and may provide important information regarding behavior. The foot is well suited to analysis of internal bone structure because it experiences the initial substrate reaction forces, due to its proximity to the substrate. Moreover, as humans and apes differ in loading of the foot, this region is relevant to questions concerning arboreal locomotion and bipedality in the hominoid fossil record.

MATERIALS AND METHODS

We apply a whole-bone/epiphysis approach to analyze trabecular and cortical bone in the distal tibia and talus of Pan troglodytes and Homo sapiens. We quantify bone volume fraction (BV/TV), degree of anisotropy (DA), trabecular thickness (Tb.Th), bone surface to volume ratio (BS/BV), and cortical thickness and investigate the distribution of BV/TV and cortical thickness throughout the bone/epiphysis.

RESULTS

We find that Pan has a greater BV/TV, a lower BS/BV and thicker cortices than Homo in both the talus and distal tibia. The trabecular structure of the talus is more divergent than the tibia, having thicker, less uniformly aligned trabeculae in Pan compared to Homo. Differences in dorsiflexion at the talocrural joint and in degree of mobility at the talonavicular joint are reflected in the distribution of cortical and trabecular bone.

DISCUSSION

Overall, quantified trabecular parameters represent overall differences in bone strength between the two species, however, DA may be directly related to joint loading. Cortical and trabecular bone distributions correlate with habitual joint positions adopted by each species, and thus have potential for interpreting joint position in fossil hominoids.

Low trabecular bone density in recent sedentary modern humans

OBJECTIVES

Research on a limited number of samples suggests that trabecular bone density (i.e., bone volume fraction, BVF) within specific articulations is lower among more sedentary Holocene agricultural populations compared with Holocene foragers, implying that activity levels have a significant effect on trabecular BVF. However, it is unclear to what extent BVF differs among groups with varying activity levels and how general this phenomenon is across multiple limb articulations. Here, we test two hypotheses that: (i) sedentary populations have lower BVF compared with active populations across limb articulations; and (ii) these declines are more uniform in the lower limb (because of its more direct relationship to mobility), and more variable in the upper limb.

MATERIALS AND METHODS

We estimated BVF in seven lower and upper limb articulations of five Holocene population samples with subsistence strategies spanning from foraging through horticultural to industrial using pQCT (peripheral Quantitative Computed Tomography).

RESULTS

Both hypotheses are largely supported. First, the most active groups have significantly greater BVF in most limb elements compared with more sedentary groups. Second, all sedentary groups have relatively similar (and lower) BVF in the lower limb but show more variation in upper limb articulations.

CONCLUSIONS

These results suggest that a decline in activity levels associated with the adoption of agriculture and industrialization significantly contributed to the reduction in BVF in recent modern humans, but specific behavioral changes, particularly in the upper limb, also affected these patterns.

Precision of dual-energy X-ray absorptiometry of the knee and heel: methodology and implications for research to reduce bone mineral loss after spinal cord injury

STUDY DESIGN

Methodological validation of dual-energy x-ray absorptiometry (DXA)-based measures of leg bone mineral density (BMD) based on the guidelines of the International Society for Clinical Densitometry.

OBJECTIVES

The primary objective of this study was to determine the precision of BMD estimates at the knee and heel using the manufacturer provided DXA acquisition algorithm. The secondary objective was to determine the smallest change in DXA-based measurement of BMD that should be surpassed (least significant change (LSC)) before suggesting that a biological change has occurred in the distal femur, proximal tibia and calcaneus.

SETTING

Academic Research Centre, Canada.

METHODS

Ten people with motor-complete SCI of at least 2 years duration and 10 people from the general population volunteered to have four DXA-based measurements taken of their femur, tibia and calcaneus. BMDs for seven regions of interest (RIs) were calculated, as were short-term precision (root-mean-square (RMS) standard deviation (g cm^-2), RMS-coefficient of variation (RMS-CV, %)) and LSC.

RESULTS

Overall, RMS-CV values were similar between SCI (3.63-10.20%, mean=5.3%) and able-bodied (1.85-5.73%, mean=4%) cohorts, despite lower absolute BMD values at each RIs in those with SCI (35%, heel to 54%, knee; P<0.0001). Precision was highest at the calcaneus and lowest at the femur. Except at the femur, RMS-CV values were under 6%.

CONCLUSIONS

For DXA-based estimates of BMD at the distal femur, proximal tibia and calcaneus, these precision values suggest that LSC values >10% are needed to detect differences between treated and untreated groups in studies aimed at reducing bone mineral loss after SCI.

Calcaneal Bone Mass Modification in Recreational Runners

BACKGROUND

The calcaneus is the bone of the foot that first receives the impact of running, generating vibrations that might have a positive effect in modifying the trabecular bone mass. The objective of this study was to determine the variation in calcaneal bone density in runners during a 6-month training season, comparing it with a control sample.

METHODS

Bone density of the heel was measured in 33 male recreational runners by means of a contact ultrasonic bone analyzer. Measurements were made on three occasions during a training season: at the beginning, at 350 km, and at 700 km. All of the runners wore the same model of running shoes during this period. Measurements of bone density were also made in a control sample of 62 men who did not engage in physical exercise.

RESULTS

There was a significant decrease in mean calcaneal bone density over the course of the training season (from 86.1 dB/MHz to 83.2 dB/MHz; P = .006), but no significant differences with the control sample value (from 80.7 dB/MHz to 81.1 dB/MHz; P = .314). The runners' body composition changed during the study period, with lean mass increasing and fat mass decreasing.

CONCLUSIONS

Distance running seems to have a negative effect on calcaneal bone mass density during the course of a 700-km training season.

Long-Term Examination of Bone Mineral Density in the Calcanei After Anterior Cruciate Ligament Reconstruction in Adolescents and Matched Adult Controls

PURPOSE

The aims were to evaluate the results 10 to 20 years after anterior cruciate ligament (ACL) reconstruction performed in adolescents in terms of bone mineral density (BMD) in the calcanei using the dual-energy x-ray absorptiometry (DXA) technique, activity level, and quality of life.

METHODS

A case-control study of adolescents who underwent ACL reconstruction between 1992 and 2002 was performed. The inclusion criterion was a unilateral ACL injury. The exclusion criteria were bilateral ACL injury, contralateral ACL reconstruction, posterior cruciate ligament injury, and previous or present fractures of either lower extremity. The BMD was measured in both calcanei using the DXA technique and compared with a control group of adult ACL-reconstructed patients and with a DXA reference database. The age of the control group was similar to that of the patient group at the time of BMD assessment, performed 60 months after reconstruction. Activity was measured with the Tegner activity scale. The EQ-5D was used to evaluate quality of life.

RESULTS

Thirty-two adolescents (11 boys and 21 girls), aged 12 to 16 years, with a symptomatic unilateral ACL rupture, underwent reconstruction at near skeletally mature age. Of these patients, 29 (91%) took part in the follow-up examination. The BMD values for the male patients were lower on the injured and non-injured sides (-15.2% [P = .02] and -11.8% [P = .05], respectively) compared with the control group. The values for the female patients were -0.8% (P = .84) and -2.2% (P = .69), respectively. Correspondingly, the BMD values for the male patients were lower on the injured and non-injured sides (-8.2% and -4.9%, respectively) compared with the male reference database. The BMD values for the female patients were higher on the injured and non-injured sides (4.1% and 4.3%, respectively) compared with the female reference database. In the control group, female patients had a significantly lower value for the Tegner activity scale preoperatively (median, 2.0; range, 0 to 5) than the female patients in the study group (median, 3.0; range, 2 to 8) (P = .006). In the study group, the Tegner activity scale at follow-up showed a significant correlation with the BMD on the injured side for male patients (ρ = 0.67, P = .03) but not on the non-injured side (ρ = 0.50, P = .14). In the control group, the Tegner activity scale at follow-up showed a significant correlation with the BMD on the non-injured side for female patients (ρ = 0.61, P = .03) but not on the injured side (ρ = 0.34, P = .25). The Tegner activity scale and EQ-5D showed no significant differences between the study groups.

CONCLUSIONS

In the long-term, the BMD in the calcanei of patients who were adolescents at the time of ACL reconstruction differed from that of a control group and a reference database. This study indicates that boys with an ACL injury and subsequent ACL reconstruction run a subsequent risk of a significantly lower BMD in their calcanei as adults and, consequently, an increased future fracture risk.

LEVEL OF EVIDENCE

Level III, case-control study.

A review of trabecular bone functional adaptation: what have we learned from trabecular analyses in extant hominoids and what can we apply to fossils?

Many of the unresolved debates in palaeoanthropology regarding evolution of particular locomotor or manipulative behaviours are founded in differing opinions about the functional significance of the preserved external fossil morphology. However, the plasticity of internal bone morphology, and particularly trabecular bone, allowing it to respond to mechanical loading during life means that it can reveal greater insight into how a bone or joint was used during an individual's lifetime. Analyses of trabecular bone have been commonplace for several decades in a human clinical context. In contrast, the study of trabecular bone as a method for reconstructing joint position, joint loading and ultimately behaviour in extant and fossil non-human primates is comparatively new. Since the initial 2D studies in the late 1970s and 3D analyses in the 1990 s, the utility of trabecular bone to reconstruct behaviour in primates has grown to incorporate experimental studies, expanded taxonomic samples and skeletal elements, and improved methodologies. However, this work, in conjunction with research on humans and non-primate mammals, has also revealed the substantial complexity inherent in making functional inferences from variation in trabecular architecture. This review addresses the current understanding of trabecular bone functional adaptation, how it has been applied to hominoids, as well as other primates and, ultimately, how this can be used to better interpret fossil hominoid and hominin morphology. Because the fossil record constrains us to interpreting function largely from bony morphology alone, and typically from isolated bones, analyses of trabecular structure, ideally in conjunction with that of cortical structure and external morphology, can offer the best resource for reconstructing behaviour in the past.

Recent origin of low trabecular bone density in modern humans

Humans are unique, compared with our closest living relatives (chimpanzees) and early fossil hominins, in having an enlarged body size and lower limb joint surfaces in combination with a relatively gracile skeleton (i.e., lower bone mass for our body size). Some analyses have observed that in at least a few anatomical regions modern humans today appear to have relatively low trabecular density, but little is known about how that density varies throughout the human skeleton and across species or how and when the present trabecular patterns emerged over the course of human evolution. Here, we test the hypotheses that (i) recent modern humans have low trabecular density throughout the upper and lower limbs compared with other primate taxa and (ii) the reduction in trabecular density first occurred in early Homo erectus, consistent with the shift toward a modern human locomotor anatomy, or more recently in concert with diaphyseal gracilization in Holocene humans. We used peripheral quantitative CT and microtomography to measure trabecular bone of limb epiphyses (long bone articular ends) in modern humans and chimpanzees and in fossil hominins attributed to Australopithecus africanus, Paranthropus robustus/early Homo from Swartkrans, Homo neanderthalensis, and early Homo sapiens. Results show that only recent modern humans have low trabecular density throughout the limb joints. Extinct hominins, including pre-Holocene Homo sapiens, retain the high levels seen in nonhuman primates. Thus, the low trabecular density of the recent modern human skeleton evolved late in our evolutionary history, potentially resulting from increased sedentism and reliance on technological and cultural innovations.

The direct effect of specific training and walking on bone metabolic markers in young adults with peak bone mass

As a prevention, a physically active lifestyle including the performance of weight-bearing exercises is important to enhance and maintain bone mineral content. Fifty young women were selected for the study. Twenty-five women carried out a specific training directed by a physiotherapist in the training group (TG), while 25 women were walking for 60 minutes in the control group (CG). Total and bone-specific alkaline phosphatase (ALP and BALP) and C-terminal cross-linked telopeptide (CTX) levels were measured at the beginning and at the end of exercise. The most remarkable change was seen in CTX levels (TG -28.89%, p < 0.001; CG -52.54%, p < 0.001), and there was also a significant difference in the values of CTX between TG and CG (p = 0.012). Therefore, walking more significantly reduced the level of CTX than special exercise. The decrease of BALP in TG was considerable but not significant (TG -4.63%, p = 0.091), while BALP levels dropped significantly in CG (-7.65%, p = 0.011), and there was a non-significant difference between the two groups (p = 0.22). Regarding the ALP level, a significant reduction was detected in TG and CG (-6.84%, p < 0.001 vs. -4.57%, p < 0.001). This study reveals that the 60-minute, middle-intensity training and the brisk walking have an immediate effect on bone metabolic markers.

Association of height and violent criminality: results from a Swedish total population study

BACKGROUND

Violent criminality is at least moderately heritable, but the mechanisms behind this remain largely unexplained. Height, a highly heritable trait, may be involved but no study has estimated the effect of height on crime while simultaneously accounting for important demographic, biological and other heritable confounders.

METHODS

We linked nationwide, longitudinal registers for 760 000 men who underwent mandatory military conscription from 1980 through 1992 in Sweden, to assess the association between height and being convicted of a violent crime. We used Cox proportional hazard modelling and controlled for three types of potential confounders: physical characteristics, childhood demographics and general cognitive ability (intelligence).

RESULTS

In unadjusted analyses, height had a moderate negative relationship to violent crime; the shortest of men were twice as likely to be convicted of a violent crime as the tallest. However, when simultaneously controlling for all measured confounders, height was weakly and positively related to violent crime. Intelligence had the individually strongest mitigating effect on the height-crime relationship.

CONCLUSIONS

Although shorter stature was associated with increased risk of violent offending, our analyses strongly suggested that this relationship was explained by intelligence and other confounding factors. Hence, it is unlikely that height, a highly heritable physical characteristic, accounts for much of the unexplained heritability of violent criminality.

The role of physical activity and diet on bone mineral indices in young men: a cross-sectional study

Background

Osteoporotic fractures are a significant cause of morbidity and mortality, particularly in developed countries. Increasing peak bone mass in young people may be the most important primary prevention strategy to reduce the risk of osteoporosis. This study aimed to examine the relationship between dietary factors and physical activity on bone mineralization in young men.

Methods

Thirty-five healthy men aged 18–25 y had anthropometric measures, body composition, resting metabolic rate, blood pressure, blood lipids, food intake, physical activity and cardiorespiratory fitness assessed.

Results

Participants who consumed more than 1000 mg/d of calcium were taller and had higher levels of whole body mineral content than participants who consumed less than 1000 mg/d of calcium. Similarly, participants who expended more than 20% of total daily energy engaged in moderate- to vigorous-intensity physical activity had higher cardiorespiratory fitness and higher levels of body mass adjusted bone mineral content than participants who did not meet this level of energy expenditure. There were no differences in blood pressure or blood lipids between participants in calcium or in physical activity energy expenditure categories.

Conclusions

A high intake of dietary calcium and high daily energy expenditure engaged in moderate- to vigorous-intensity physical activity were positively associated with bone mineralization in young men, particularly in the lumbar region.

New reference values for calcium

The nutrition societies of Germany, Austria and Switzerland are the joint editors of the 'reference values for nutrient intake'. They have revised the reference values for the intake of calcium and published them in June 2013. The reference values for the calcium intake for infants are derived from the calcium content of breast milk. For infants from 4 to <12 months of age, the calcium intake from solid foods is included in addition to the calcium intake from breast milk. Thus, the reference values for infants are estimated values; they are 220 mg/day for infants to <4 months and 330 mg/day for infants from 4 to <12 months of age. As a parameter for determining the calcium requirement in children and adolescents, calcium retention is taken into account. The average requirement is calculated by the factorial method. A balanced calcium metabolism is calculated based upon calcium balance studies and used as a parameter for the determination of the calcium requirement in adults. On the basis of the average requirement, recommended calcium intake levels for children, adolescents and adults are derived. Depending on age, the recommended calcium intake ranges between 600 mg/day for children aged 1 to <4 years and 1,200 mg/day for adolescents aged 13 to <19 years; for adults, it is 1,000 mg/day.

Self-reported recreational exercise combining regularity and impact is necessary to maximize bone mineral density in young adult women: a population-based study of 1,061 women 25 years of age

Recreational physical activity in 25-year-old women in Sweden increases bone mineral density (BMD) in the trochanter by 5.5% when combining regularity and impact. Jogging and spinning were especially beneficial for hip BMD (6.4-8.5%). Women who enjoyed physical education in school maintained their higher activity level at age 25.

INTRODUCTION

The aims of this study were to evaluate the effects of recreational exercise on BMD and describe how exercise patterns change with time in a normal population of young adult women.

METHODS

In a population-based study of 1,061 women, age 25 (±0.2), BMD was measured at total body (TB-BMD), femoral neck (FN-BMD), trochanter (TR-BMD), and spine (LS-BMD). Self-reported physical activity status was assessed by questionnaire. Regularity of exercise was expressed as recreational activity level (RAL) and impact load as peak strain score (PSS). A permutation (COMB-RP) was used to evaluate combined endurance and impacts on bone mass.

RESULTS

More than half of the women reported exercising on a regular basis and the most common activities were running, strength training, aerobics, and spinning. Seventy percent participated in at least one activity during the year. Women with high RAL or PSS had higher BMD in the hip (2.6-3.5%) and spine (1.5-2.1%), with the greatest differences resulting from PSS (p < 0.001-0.02). Combined regularity and impact (high-COMB-RP) conferred the greatest gains in BMD (FN 4.7%, TR 5.5%, LS 3.1%; p < 0.001) despite concomitant lower body weight. Jogging and spinning were particularly beneficial for hip BMD (+6.4-8.5%). Women with high-COMB-RP scores enjoyed physical education in school more and maintained higher activity levels throughout compared to those with low scores.

CONCLUSION

Self-reported recreational levels of physical activity positively influence BMD in young adult women but to maximize BMD gains, regular, high-impact exercise is required. Enjoyment of exercise contributes to regularity of exercising which has short- and long-term implications for bone health.

The beneficial effect of leisure-time physical activity on bone mineral density in pre- and postmenopausal women

Regular exercise and physical activity (PA) are known to be protective factors for maintaining bone mineral density (BMD) and preventing osteoporotic fracture. We investigated the associations between leisure-time PA and BMD in 2,903 premenopausal and 2,267 postmenopausal women in Korea. BMDs of the lumbar spine and femur were measured using dual-energy X-ray absorptiometry. Leisure-time PA levels were assessed by a self-administrated questionnaire, and a total metabolic equivalent (MET) score was obtained. Regardless of menopausal status, performing more than moderate levels of leisure-time PA or total MET score had a significant positive association with BMD at both the lumbar spine and femur. In the premenopausal group, women whose total MET score was 1,050-1,500 (MET-min/week) appeared to have the highest lumbar spine and femoral BMD (p < 0.001). The associations between PA level and lumbar spine and femoral BMD were also shown in the postmenopausal group (p < 0.001). In addition, we found dose-response relationships between increasing exercise level and femoral BMD in both the premenopausal and postmenopausal groups. Our results indicate that a more than moderate level of leisure-time PA plays a role in maintaining BMD.