Bone Traits Research Articles

Comparison of liver and bone health of two laying hen strains kept in different cage systems

Summary Concerns have been increasing about conventional cages for laying hens in connection with welfare. Liver and bone disorders of laying hens are major problems. Therefore, the aim of this experiment was to investigate the differences in liver and bone traits of two laying strains kept in conventional and enriched cages. A total of 532 two Lohmann Brown Classic (LB) and 532 Lohmann LSL Classic (LW) hens were housed from 16 to 73 weeks in either conventional cages or enriched cages. Enriched cages had a nesting area, scratch pad, perch and claw shortener. At 73 weeks of age, blood parameters (alanine amino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP), calcium (Ca), phosphor (P), cholesterol and triglycerides), relative liver weight, fatty liver score and bone parameters (weight, length, diameter, maximum load, deformation at maximum load and stiffness of tibia and femur) were determined. The cage type affected only serum ALT, AST, ALP and cholesterol levels. Differences of liver and bone parameters between both cage types were not statistically significant. Serum ALT, ALP and P level and also weight and diameter of examined bones were affected by strain. This study indicates that cage type and cage type × strain interactions have limited effect on the liver and bone health.

Preterm Children Born Small for Gestational Age are at Risk for Low Adult Bone Mass.

Cross-sectional studies suggest that premature birth and low birth weight may both be associated with low peak bone mass. We followed bone traits in preterm individuals and controls for 27 years and examined the effects of birth weight relative to gestational age [stratified as small for gestational age (SGA) or appropriate for gestational (AGA)] on adult bone mineral density (BMD). We measured distal forearm BMC (g/cm) and BMD (g/cm(2)) with single-photon absorptiometry (SPA) in 46 preterm children (31 AGA and 15 SGA) at mean age 10.1 years (range 4-16) and in 84 healthy age-matched children. The measurements were repeated 27 years later with the same SPA apparatus but then also with dual energy absorptiometry and peripheral computed tomography (pQCT). Preterm individuals were shorter (p = 0.03) in adulthood than controls. Preterm AGA individuals had similar BMC and BMD height-adjusted Z-scores in adulthood compared to controls. Preterm SGA individuals had lower distal forearm BMC and BMD height-adjusted Z-scores in adulthood than both controls and preterm AGA individuals. Preterm SGA individuals had lower gain from childhood to adulthood in distal forearm BMC height-adjusted Z-scores than controls (p = 0.03). The deficits in preterm SGA individuals in adulthood were also captured by DEXA in height-adjusted femoral neck (FN) BMC Z-score and height-adjusted FN BMD Z-score and by pQCT in tibial cross-sectional area (CSA) Z-score and stress strain index (SSI) Z-score, where all measurements were lower than controls (all p values <0.05). Preterm SGA individuals are at increased risk of reaching low adult bone mass, at least partly due to a deficit in the accrual of bone mineral during growth. In our cohort, we were unable to find a similar risk in preterm AGA individuals.

Osteoarthritis of the Distal Interphalangeal and First Carpometacarpal Joints is Associated with High Bone Mass in Women and Small Bone Size and Low Lean Mass in Men.

Objective: To determine if primary hand osteoarthritis (OA) is associated with abnormal bone and anthropometric traits.Methods: We used DXA to measure total body bone mineral density (BMD), femoral neck width (bone size) and total body lean and fat mass in 39 subjects with hand OA (primary DIP and/or CMC I) and 164 controls. Data are presented as mean Z-scores or Odds Ratios (OR) with 95% confidence intervals.Results: Women with hand OA had (compared to controls) higher BMD (0.5(0.1,0.9)) but similar bone size (-0.3(-0.8,0.2)), lean mass (0.3(-0.3,0.9)), fat mass (-0.1(-0.6,0.5)) and BMI (0.0(-0.6,0.6)). Men with hand OA had (compared to controls) similar BMD (-0.1(-0.7,0.6)), smaller bone size (-0.5(-1.1,-0.01)), lower lean mass (-0.6(-1.1,-0.04)), and similar fat mass (-0.2(-0.7,0.4)) and BMI -0.1(-0.6,0.6). In women, each SD higher BMD was associated with an OR of 1.8 (1.03, 3.3) for having hand OA. In men each SD smaller bone size was associated with an OR of 1.8 (1.02, 3.1) and each SD lower proportion of lean body mass with an OR of 1.9 (1.1, 3.3) for having hand OA.Conclusion: Women with primary DIP finger joint and/or CMC I joint OA have a phenotype with higher BMD while men with the disease have a smaller bone size and lower lean body mass.

Microbial phytase improves performance and bone traits in broilers fed diets based on soybean meal and containing lupin meal

A completely randomised design study with a 3 × 2 factorial arrangement was conducted. A total of 480 male broiler chickens were used to determine the influence of phytase addition, plant protein source [soybean meal, soybean meal + 200 g/kg of blue lupin meal (Lupinus angustifolius L.) or soybean meal + 200 g/kg yellow lupin meal (Lupinus luteus L.)] on performance of broiler chickens, ileal calcium (Ca), phosphorus (P) and protein digestibility, tibia bone characteristics and nitrogen-corrected apparent metabolisable energy. All diets were deficient in Ca, available P as well as lysine and total sulfur amino acids. Birds fed different protein sources were characterised by similar bodyweight gain and feed intake during the whole trial but feed conversion ratio was higher when birds were fed supplemented with yellow lupin meal (P &lt; 0.05). Phytase improved bodyweight gain and feed conversion ratio regardless of protein source (P &lt; 0.05). Diets supplemented with 200 g/kg blue or yellow lupin meal were found to be lower in nitrogen-corrected apparent metabolisable energy than soybean meal diets (P &lt; 0.05). Birds fed diets supplemented with phytase were characterised by higher utilisation of Ca and P than birds whose feed was not supplemented with phytase (P &lt; 0.05). Tibia bone ash as well as Ca content was similar across protein sources (P &gt; 0.05), whereas tibia P content was lower when soybean meal or blue lupin meal was used (P &lt; 0.05). Birds fed diets supplemented with blue lupin meal were characterised by the highest tibia P content (P &lt; 0.05). Birds fed phytase-supplemented diets were characterised by higher tibia Ca and P content irrespective of protein source.

LRP receptor family member associated bone disease.

A dozen years ago the identification of causal mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene involved in two rare bone disorders propelled research in the bone field in totally new directions. Since then, there have been an explosion in the number of reports that highlight the role of the Wnt/β-catenin pathway in the regulation of bone homeostasis. In this review we discuss some of the most recent reports (in the past 2 years) highlighting the involvement of the members of the LRP family (LRP5, LRP6, LRP4, and more recently LRP8) in the maintenance of bone and their implications in bone diseases. These reports include records of new single nucleotides polymorphisms (SNPs) and haplotypes that suggest variants in these genes can contribute to subtle variation in bone traits to mutations that give rise to extreme bone phenotypes. All of these serve to further support and reinforce the importance of this tightly regulated pathway in bone. Furthermore, we discuss provocative reports suggesting novel approaches through inhibitors of this pathway to treat rarer diseases such as Osteoporosis-Pseudoglioma Syndrome (OPPG), Osteogenesis Imperfecta (OI), and Sclerosteosis/Van Buchem disease. It is hoped that by understanding the role of each component of the pathway and their involvement in bone diseases that this knowledge will allow us to develop new, more effective therapeutic approaches for more common diseases such as post-menopausal osteoporosis, osteoarthritis, and rheumatoid arthritis as well as these rarer bone diseases.

Genetic regulation of bone metabolism in the chicken: similarities and differences to Mammalian systems.

Birds have a unique bone physiology, due to the demands placed on them through egg production. In particular their medullary bone serves as a source of calcium for eggshell production during lay and undergoes continuous and rapid remodelling. We take advantage of the fact that bone traits have diverged massively during chicken domestication to map the genetic basis of bone metabolism in the chicken. We performed a quantitative trait locus (QTL) and expression QTL (eQTL) mapping study in an advanced intercross based on Red Junglefowl (the wild progenitor of the modern domestic chicken) and White Leghorn chickens. We measured femoral bone traits in 456 chickens by peripheral computerised tomography and femoral gene expression in a subset of 125 females from the cross with microarrays. This resulted in 25 loci for female bone traits, 26 loci for male bone traits and 6318 local eQTL loci. We then overlapped bone and gene expression loci, before checking for an association between gene expression and trait values to identify candidate quantitative trait genes for bone traits. A handful of our candidates have been previously associated with bone traits in mice, but our results also implicate unexpected and largely unknown genes in bone metabolism. In summary, by utilising the unique bone metabolism of an avian species, we have identified a number of candidate genes affecting bone allocation and metabolism. These findings can have ramifications not only for the understanding of bone metabolism genetics in general, but could also be used as a potential model for osteoporosis as well as revealing new aspects of vertebrate bone regulation or features that distinguish avian and mammalian bone.

A new WNT on the bone: WNT16, cortical bone thickness, porosity and fractures.

The last decade has provided abundant data implicating the WNT pathway in bone development and in the regulation of skeletal homeostasis. Rare human mutations together with gain- and loss-of-function approaches in mice have clearly demonstrated that disrupted regulation of this pathway leads to altered bone mass. In addition to these rare human and mice mutations, large population-based genome-wide association studies (GWASs) have identified single-nucleotide polymorphisms in ∼60 loci strongly associated with variations in bone mineral density (BMD) at different skeletal sites. Among the loci/genes identified by BMD GWAS, components of the WNT signaling pathway are numerous and have been shown to contribute to skeletal development and homeostasis. Within the components of WNT signaling, the gene coding for WNT16, one of the 19 WNT ligands of the human genome, has been found strongly associated with specific bone traits such as cortical bone thickness, cortical porosity and fracture risk. Recently, the first functional characterization of Wnt16 has confirmed the critical role of Wnt16 in the regulation of cortical bone mass and bone strength in mice. These reports have extended our understanding of Wnt16 function in bone homeostasis and have not only confirmed the unique association of Wnt16 with cortical bone and fracture susceptibility, as suggested by GWAS in human populations, but have also provided novel insights into the biology of this WNT ligand and the mechanism(s) by which it regulates cortical but not trabecular bone homeostasis. Most interestingly, Wnt16 appears to be a strong anti-resorptive soluble factor acting on both osteoblasts and osteoclast precursors.

Measures Of Muscle Function As Related To Bone Strength

The functional muscle-bone unit, described by the mechanostat theory, illustrates the dependence of bone strength on muscle size and strength. As a result muscle force measures could be used to assess skeletal health but questions remain as to the optimal measure of muscle function that relates to bone strength. Leg extensor strength was considered a weak correlate to bone mineral density (BMD) (Duncan et al. 2002) however these results may be due to the use of dual energy X-ray absorptiometry (DXA) and areal BMD measures. Peripheral quantitative tomography (pQCT) used in the current study has the ability to measure all bone traits contributing to strength including BMD, area, and geometry. Most studies using pQCT correlate bone strength with muscle area measurements but muscle function measurements may be more useful in athletics and in clinics. PURPOSE: To investigate the relationship between common muscle function tests (direct torque measures) and bone strength in cross country athletes. What measure of muscle function (Grip Strength, 1 Rep Max of Leg Extensors, Peak Power-vertical jump) relates to bone strength? METHODS: Sixteen athletes from CSU East Bay Collegiate Cross Country team, 7 females and 9 males (age 19.7 ± 1.4 yrs., body fat % 14.9 ± 6.9%) performed a maximum grip strength (GS) test using a hand grip dynamometer, a maximum leg press to test one rep max (1RM) and a vertical jump test using the Vertek to measure peak power (PP). Cortical area (Ct.Ar), cortical bone mineral density (cBMD), moment of inertia (J) and bone strength (polar strength-strain index, SSI) were measured using pQCT at 25% tibial length. Pearson correlations determined muscle bone relationships. RESULTS: Grip Strength, 1RM, and Peak Power were all significantly correlated with Ct.Ar, J, and SSI. However, none of the muscle function measures were correlated with cBMD. Bone strength resulted in significant and strong correlations; GS (R2=0.4378, p=0.005), 1RM (R2=0.4919, p=0.003), PP (R2=0.5642, p=0.001). J, a measure of the geometry/architecture of bone yielded stronger relationships; GS (R2=0.6571, p =0.006), 1RM (R2=0.7076, p =0.002), PP (R2=0.7898, p =0.0005). CONCLUSIONS: The muscle-bone unit can be measured using functional muscle measurements; GS, 1RM and PP all strongly correlated with bone strength. However, muscle function seems to have the greatest effect on the geometry of the bone and little influence on the cBMD.

Additive Genetic Effects on Circulating Periostin Contribute to the Heritability of Bone Microstructure.

Genetic factors account for 60-80% of the areal bone mineral density (aBMD) variance, whereas the heritability of bone microstructure is not clearly established. aBMD and microstructure are under the control of osteocytes, which regulate bone formation through the expression of molecules such as sclerostin (SOST) and periostin (POSTN). We hypothesized that additive genetic effects contribute to serum levels of SOST and POSTN and thereby to the individual variance of bone microstructure. In a retrospective analysis of 432 subjects from the Geneva Retiree Cohort age 64.9 ± 1.4 years and 96 of their offspring age 37.9 ± 5.7 years, we measured serum SOST (sSOST) and serum POSTN (sPOSTN), distal radius and tibia microstructure, hip and lumbar spine aBMD, and bone turnover markers, Heritability (h(2), %) was calculated as twice the slope of the regression (β) between parents and offspring. cPOSTN levels were significantly higher in men than women and in offspring than parents. h(2) values for bone microstructural traits ranged from 22-64% depending on the envelope (trabecular [Tb] or cortical [Ct]) and skeletal site (radius or tibia), whereas h(2) for sPOSTN and sSOST was 50% and 40%, respectively. sPOSTN was positively associated with Tb bone volume on total volume and Ct thickness, and negatively with Ct porosity. The associations for Ct parameters remain significant after adjustment for propetide of type-I procollagen, cross-linked telopeptide of type I collagen, femoral neck aBMD, sex or age. After adjustment of bone traits for sPOSTN, h(2) values decreased for several Tb and Ct bone parameters, but not for aBMD. In contrast, adjusting for sSOST did not alter h(2) values for bone traits. Additive genetic effects account for a substantial proportion of the individual variance of bone microstructure, sPOSTN, and sSOST. sPOSTN is largely inherited as a sex-related trait and carries an important contribution to the heritability of bone microstructure, indicating that these traits are at least partly determined by common genetic effects.

Presence of knee osteophytes is heritable and linked to regions of CHR. 19 and 2 that contain TGFB1 and SPP2

Presence of knee osteophytes is heritable and linked to regions of CHR. 19 and 2 that contain TGFB1 and SPP2

Neonatal Pig Femur Integrity Responses to Dietary Vitamin D and P Depend on Maternal Dietary Vitamin D

Kyphosis, an idiopathic disease, occurs in swine and humans. We induced kyphosis by altering maternal dietary vitamin D (D) and pig dietary D, Ca and P. The objective was to characterize bone traits and gene expression in the kyphosis model and assess maternal carryover effects. Traits from mechanical tests to characterize femur integrity are reported herein. Sows were fed diets with 0, 325 or 1750 IU D/kg (n = 6, 8, or 9/diet). At weaning (23 ± 2 d) pigs were fed diets with 0 (-D) or 280 (+D) IU D/kg, each with 95% (95P) or 120% (120P) of the P requirement. Pigs were killed at birth (n = 23), weaning (n = 22), and at the end of nursery (n = 185) for bone and tissue analysis. Excised femurs were subjected to a 4-point bending test to determine bending moment (BM), stress, strain, and modulus of elasticity (ME) at the yield point of load deformation curves. Mass moment of inertia (MOI) was derived from CT scans. ME encompasses of BM, stress, strain and MOI and is assumed to be a constant property of a material. No differences in ME were detected at birth. At weaning ME increased in pigs produced by sows fed 1750 (P < 0.05). At the end of nursery ME depended on maternal diets (interaction, P < 0.05). ME increased in pigs fed +D95P if produced by sows fed 0 or 325 but decreased if produced by sows fed 1750. As previously reported, DXA whole body bone mineral density also indicated maternal carryover effects, but the pattern differed among diets. Therefore whole body bone and femur integrity traits differ, but provide unique characterization of the model. As previously reported, the kyphosis model was further characterized by molecular analysis of bone and D homeostatic cell signaling mechanisms. All traits contribute to the characterization of the kyphosis model but a specific mechanism by which the deformity is induced has yet to be determined.

Oregano, rosemary and vitamin E dietary supplementation in growing rabbits: Effect on growth performance, carcass traits, bone development and meat chemical composition

The study aimed to evaluate the effect of dietary supplementation with different natural additives (aqueous extracts) on the performance of growing rabbits, the nutritional composition and oxidative stability of their meat and on their hind leg bone traits. For this experiment, 200 New Zealand White rabbits weaned at 30 days of age were randomly allocated into five dietary groups (n=40 rabbits/group) until 80 days of age, when they were sacrificed. Dietary groups were: S (standard diet with no supplementation), E (standard diet+150ppm vitamin E positive control), O (standard diet+0.2% oregano, Origanum vulgare, aqueous extract), R (standard diet+0.2% rosemary, Rosmarinus officinalis, aqueous extract) and OR (standard diet+0.1% oregano extract+0.1% rosemary extract). An additional 50ppm vitamin E was added to each diet. Rabbits in the O and OR groups showed the highest final live weight and carcass weight (P<0.001). Oregano supplemented animals also had the best feed conversion ratio. Longissimus dorsi (LD) meat of E and R rabbits had higher protein content compared to O and OR (P<0.001) which had a higher moisture content than E rabbits (P<0.005). All dietary treatments improved the oxidative stability of the LD meat compared to the S group. Treatments O and E were the most effective in delaying the lipid oxidation of LD meat, followed by the OR and R diets (P<0.005). No significant differences among groups in composition of the hind leg meat (HL) were observed. The O rabbits had a higher bone weight (P<0.05) than E animals and this difference was mainly ascribable to femur weight (P<0.01). In conclusion, the study showed that supplementation with 0.2% oregano can have a positive effect on productive performance and meat quality of rabbits.

Genetic parameters and mapping quantitative trait loci associated with tibia traits in broilers.

Selection among broilers for performance traits is resulting in locomotion problems and bone disorders, once skeletal structure is not strong enough to support body weight in broilers with high growth rates. In this study, genetic parameters were estimated for body weight at 42 days of age (BW42), and tibia traits (length, width, and weight) in a population of broiler chickens. Quantitative trait loci (QTL) were identified for tibia traits to expand our knowledge of the genetic architecture of the broiler population. Genetic correlations ranged from 0.56 ± 0.18 (between tibia length and BW42) to 0.89 ± 0.06 (between tibia width and weight), suggesting that these traits are either controlled by pleiotropic genes or by genes that are in linkage disequilibrium. For QTL mapping, the genome was scanned with 127 microsatellites, representing a coverage of 2630 cM. Eight QTL were mapped on Gallus gallus chromosomes (GGA): GGA1, GGA4, GGA6, GGA13, and GGA24. The QTL regions for tibia length and weight were mapped on GGA1, between LEI0079 and MCW145 markers. The gene DACH1 is located in this region; this gene acts to form the apical ectodermal ridge, responsible for limb development. Body weight at 42 days of age was included in the model as a covariate for selection effect of bone traits. Two QTL were found for tibia weight on GGA2 and GGA4, and one for tibia width on GGA3. Information originating from these QTL will assist in the search for candidate genes for these bone traits in future studies.

The Effects of Elk Velvet Antler Dietary Supplementation on Physical Growth and Bone Development in Growing Rats.

Elk velvet antler (EVA) has been used in traditional Oriental medicine for centuries to promote general health; however, little evidence for its effect on bone development is available. We investigated the effects of lifelong exposure of Wistar rats to a diet containing 10% EVA on physical growth and bone development. Measurements included weekly body weights, blood chemistry and kidney and testis/ovary indices (sacrificed at 5, 9, or 16 weeks of age), and bone traits of the femur bones by peripheral quantitative computed tomography (pQCT). Mean body weights were higher in the EVA group at 4–8 weeks in males and at 5 weeks of age in females. The kidney indices were greater in EVA dietary supplemented male rats at 5 and 16 weeks of age, in females at 16 weeks of age, and testis/ovary indices at 5 weeks of age. The femoral length was increased in both males and females at 5 weeks, and several pQCT-measured parameters had increased in EVA males and females. The activity of alkaline phosphatase (ALP) increased in EVA group while the content of calcium and phosphorus did not differ among groups. Our results seem to support a role for dietary supplementation of EVA on growth and bone development in this model.

The influence of anthropometry and body composition on children's bone health: the childhood health, activity and motor performance school (the CHAMPS) study, Denmark.

Overweight, physical inactivity and sedentary behaviour have become increasing problems during the past decade. Increased sedentary behaviour may change the body composition (BC) by increasing the fat mass relative to the lean mass (LM). These changes may influence bone health to describe how anthropometry and BC predict the development of the bone accruement. The longitudinal study is a part of The CHAMPS study-DK. Children were DXA scanned at baseline and at 2-year follow-up. BC (LM, BF %) and BMC, BMD and BA were measured. The relationship between bone traits, anthropometry and BC was analysed by multilevel regression analyses. Of the invited children, 742/800 (93%) accepted to participate. Of these, 682/742 (92%) participated at follow-up. Mean (range) of age at baseline was 9.5 years (7.7-12.1). Height, BMI, LM and BF % predicted bone mineral accrual and bone size positively and independently. Height and BMI are both positive predictors of bone accruement. LM is a more precise predictor of bone traits than BF % in both genders. The effects of height and BMI and LM on bone accruement are nearly identical in the two genders, while changes in BF % have different but positive effects on bone accretion in both boys and girls.

Effects of bone-specific physical activity, gender and maturity on tibial cross-sectional bone material distribution: a cross-sectional pQCT comparison of children and young adults aged 5–29 years

Growth is the opportune time to modify bone accrual. While bone adaptation is known to be dependent on local loading and consequent deformations (strain) of bone, little is known about the effects of sex, and bone-specific physical activity on location-specific cross-sectional bone geometry during growth. To provide more insight we examined bone traits at different locations around tibial cross sections, and along the tibia between individuals who vary in terms of physical activity exposure, sex, and pubertal status. Data from 304 individuals aged 5–29years (172 males, 132 females) were examined. Peripheral quantitative computed tomography (pQCT) was applied at 4%, 14%, 38%, and 66% of tibial length. Maturity was established by estimating age at peak height velocity (APHV). Loading history was quantified with the bone-specific physical activity questionnaire (BPAQ). Comparisons, adjusted for height, weight and age were made between sex, maturity, and BPAQ tertile groups. Few to no differences were observed between sexes or BPAQ tertiles prior to APHV, whereas marked sexual dimorphism and differences between BPAQ tertiles were observed after APHV. Cross-sectional location-specific differences between BPAQ tertiles were not evident prior to APHV, whereas clear location-specificity was observed after APHV. In conclusion, the skeletal benefits of physical activity are location-specific in the tibia. The present results indicate that the peri- or post-pubertal period is likely a more favourable window of opportunity for enhancing cross-sectional bone geometry than pre-puberty. Increased loading during the peri-pubertal period may enhance the bone of both sexes.

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.

The associations of serum serotonin with bone traits are age- and gender-specific.

ContextSerotonin plays a potential role in bone metabolism, but the nature and extent of this relationship is unclear and human studies directly addressing the skeletal effect of circulating serotonin are rare.ObjectiveThe study aimed to investigate the associations between serum serotonin and bone traits at multiple skeletal sites in women and men.Subjects and MethodsSubjects were part of the CALEX-family study and comprised 235 young women, 121 premenopausal women, 124 postmenopausal women, and 168 men. Body composition was assessed using DXA, as was areal bone mineral density (aBMD) of spine, femur and whole body. In addition, pQCT was used to determine bone properties at tibial midshaft and distal radius. Fasting serum serotonin concentration was assessed using a competitive enzyme-linked immunosorbent assay.ResultsSerum serotonin declined with advancing age both in females and males (all p<0.01). Serotonin was negatively correlated with weight, BMI, lean and fat mass in women (r = −0.22 to −0.39, all p<0.001), but positively with height and lean mass in men (all p<0.01). In the premenopausal women, serotonin was negatively correlated with lumbar spine aBMD (r = −0.23, p<0.05) but the statistical significance disappeared after adjustment for weight. Conversely, in postmenopausal women, serotonin was positively correlated with whole body and femur aBMD, as well as with distal radius bone mineral content and volumetric BMD (r = 0.20 to 0.30, all p<0.05), and these associations remained significant after adjustment for weight. In men, no significant associations were found between serotonin and bone traits.ConclusionSerum serotonin is positively associated with bone traits in postmenopausal women, but not in premenopausal women or men. This partially supports the idea of circulating serotonin playing a role in the regulation of bone metabolism, but also indicates the importance of gender and age specific factors.

Exercise in youth: High bone mass, large bone size, and low fracture risk in old age.

Physical activity is favorable for peak bone mass but if the skeletal benefits remain and influence fracture risk in old age is debated. In a cross-sectional controlled mixed model design, we compared dual X-ray absorptiometry-derived bone mineral density (BMD) and bone size in 193 active and retired male elite soccer players and 280 controls, with duplicate measurements of the same individual done a mean 5 years apart. To evaluate lifetime fractures, we used a retrospective controlled study design in 397 retired male elite soccer players and 1368 controls. Differences in bone traits were evaluated by Student's t-test and fracture risk assessments by Poisson regression and Cox regression. More than 30 years after retirement from sports, the soccer players had a Z-score for total body BMD of 0.4 (0.1 to 0.6), leg BMD of 0.5 (0.2 to 0.8), and femoral neck area of 0.3 (0.0 to 0.5). The rate ratio for fracture after career end was 0.6 (0.4 to 0.9) and for any fragility fracture 0.4 (0.2 to 0.9). Exercise-associated bone trait benefits are found long term after retirement from sports together with a lower fracture risk. This indicates that physical activity in youth could reduce the burden of fragility fractures.

Tibial and fibular mid-shaft bone traits in young and older sprinters and non-athletic men.

High impact loading is known to prevent some of the age-related bone loss but its effects on the density distribution of cortical bone are relatively unknown. This study examined the effects of age and habitual sprinting on tibial and fibular mid-shaft bone traits (structural, cortical radial and polar bone mineral density distributions). Data from 67 habitual male sprinters aged 19-39 and 65-84years, and 60 non-athletic men (referents) aged 21-39 and 65-80years are reported. Tibial and fibular mid-shaft bone traits (strength strain index SSI, cortical density CoD, and polar and radial cortical density distributions) were assessed with peripheral quantitative computed tomography. Analysis of covariance (ANCOVA) adjusted for height and body mass indicated that the sprinters had 21% greater tibial SSI (P<0.001) compared to the referents, with no group×age-group interaction (P=0.54). At the fibula no group difference or group×age-group interaction was identified (P=0.12-0.81). For tibial radial density distribution ANCOVA indicated no group×radial division (P=0.50) or group×age-group×division interaction (P=0.63), whereas an age×radial division interaction was observed (P<0.001). For polar density distribution, no age-group×polar sector (P=0.21), group×polar sector (P=0.46), or group×age-group×polar sector interactions were detected (P=0.15). Habitual sprint training appears to maintain tibial bone strength, but not radial cortical density distribution into older age. Fibular bone strength appeared unaffected by habitual sprinting.