Quantitative genetic study of radiographic hand bone size and geometry

Familial resemblance of bone turnover rate in men aged 40 and over-the MINOS study

Familial resemblance of bone mineral density (BMD) is well known in both sexes. Fewer data concern the familial resemblance of bone turnover markers (BTMs) and bone size in men. Our aim was to assess the correlation of BMD, bone size, BTM levels and hormones regulating bone turnover in 50 pairs of brothers aged ≥ 40 and 50 pairs of unrelated men matched for age, weight and height. BMD was measured at the lumbar spine, hip, forearm and whole body. We measured serum osteocalcin (OC), bone-specific alkaline phosphatase (bone ALP), N-terminal propeptide of type I procollagen (PINP) and C-terminal telopeptide of type I collagen (CTX-I) as well as urinary free and total deoxypyridinoline (DPD) and CTX-I. After adjustment for age, weight, bioavailable 17β-estradiol, and parathyroid hormone, all the BTMs (except bone ALP) were significantly correlated in the brothers (ICC = 0.36-0.64). Most of these correlations were significantly stronger than in the unrelated men. Bone size correlated significantly between the brothers (ICC = 0.55-0.65). These correlations were significantly stronger than in the unrelated men. BMD correlated between the brothers at most of the skeletal sites and, for some of them, more strongly than in the unrelated men. Serum levels of LDL-cholesterol and triglycerides were significantly correlated in the brothers, but not more strongly than in the unrelated men. BTM levels correlated independently in the brothers aged ≥ 40, when their shared environment was limited. These data suggest a substantial hereditary determinism of the BTM levels in men.

Skeletal growth and the changing genetic landscape during childhood and adulthood

Growth, development, and decline of the human skeleton are of central importance to physical anthropology. All processes of skeletal growth (longitudinal growth as well as gains and losses of bone mass) are subjected to environmental and genetic influences. These influences, and their relative contributions to the phenotype, can be asserted at any stage of life. We present here the gross phenotypic and genetic landscapes of four skeletal traits, and show how they vary across the life span. Phenotypic sex differences are found in bone diameter and cortical index (a ratio of cortical thickness over bone diameter) at a very early age and continue throughout most of life. Sexual dimorphism in summed cortical thickness and bone length, however, is not evident until shortly after the pubertal growth spurt. Genetic contributions (heritability) to these skeletal phenotypes are generally moderate to high. Bone length and bone diameter (which both scale with body size) tend to have the highest heritability, with heritability of bone length fairly stable across ages (with a notable dip in early childhood) and that of bone diameter peaking in early childhood. The bone traits summed cortical thickness and cortical index that may better reflect bone mass, a more plastic phenomenon, have slightly lower genetic influences, on average. Results from our phenotypic and genetic landscapes serve three key purposes: 1) demonstration of the integrated nature of the genetic and environmental underpinnings of skeletal form, 2) identification of periods of bone's relative sensitivity to genetic and environmental influences, 3) and stimulation of hypotheses predicting the effects of exposure to environmental variables on the skeleton, given variation in the underlying genetic architecture.

Cortical bone health shows significant linkage to chromosomes 2p, 3p, and 17q in 10-year-old children

Genes play an important role in lifelong skeletal health. Genes that influence bone building during childhood have the potential to affect bone health not only throughout childhood but also into adulthood. Given that peak bone mass is a significant predictor of adult fracture risk, it is imperative that the genetic underpinnings of the normal pediatric skeleton are uncovered. In a sample of 600 10-year-old children from 144 families in the Fels Longitudinal Study, we examined radiographic cortical bone measures of the second metacarpal. Morphometic measurements included bone width, medial and lateral cortical thicknesses, and the calculated cortical index representing the amount of cortex relative to bone width. We then conducted genome-wide linkage analysis on these traits in 440 genotyped individuals using the SOLAR analytic platform. Significant quantitative trait loci (QTL) were identified for bone traits on three separate chromosomes. A QTL for medial cortical thickness was localized to chromosome 2p25.2. A QTL for lateral cortical thickness was localized to chromosomal region 3p26.1-3p25.3. Finally, a QTL detected for cortical index was localized to the 17q21.2 chromosomal region. Each region contains plausible candidate genes for pediatric skeletal health, some of which confirm findings from studies of adulthood bone, and for others represent novel candidate genes for skeletal health.

PLCL1 rs7595412 variation is not associated with hip bone size variation in postmenopausal Danish women

BACKGROUND

Bone size (BS) variation is under strong genetic control and plays an important role in determining bone strength and fracture risk. Recently, a genome-wide association study identified polymorphisms associated with hip BS variation in the PLCL1 (phospholipase c-like 1) locus. Carriers of the major A allele of the most significant polymorphism, rs7595412, have around 17% larger hip BS than non-carriers. We therefore hypothesized that this polymorphism may also influence postmenopausal complications.

METHODS

The effects of rs7595412 on hip BS, bone mineral density (BMD), vertebral fractures, serum Crosslaps and osteocalcin levels were analyzed in 1,191 postmenopausal Danish women.

RESULTS

This polymorphism had no influence on hip and spine BS as well as on femur and spine BMD. Women carrying at least one copy of the A allele had lower levels of serum osteocalcin as compared with those homozygous for the G allele (p = 0.03) whereas no effect on serum Crosslaps was detected. Furthermore, women homozygous for the A allele were more affected by vertebral fractures than those carrying at least one copy of the G allele (p = 0.04).

CONCLUSIONS

In postmenopausal women, our results suggest that the PLCL1 rs7595412 polymorphism has no obvious effect on hip BS or BMD but may be nominally associated with increased proportion of vertebral fracture and increased levels of osteocalcin.

Systems analysis of bone

The genetic variants contributing to variability in skeletal traits has been well studied, and several hundred QTLs have been mapped and several genes contributing to trait variation have been identified. However, many questions remain unanswered. In particular, it is unclear whether variation in a single gene leads to alterations in function. Bone is a highly adaptive system and genetic variants affecting one trait are often accompanied by compensatory changes in other traits. The functional interactions among traits, which is known as phenotypic integration, has been observed in many biological systems, including bone. Phenotypic integration is a property of bone that is critically important for establishing a mechanically functional structure that is capable of supporting the forces imparted during daily activities. In this paper, bone is reviewed as a system and primarily in the context of functionality. A better understanding of the system properties of bone will lead to novel targets for future genetic analyses and the identification of genes that are directly responsible for regulating bone strength. This systems analysis has the added benefit of leaving a trail of valuable information about how the skeletal system works. This information will provide novel approaches to assessing skeletal health during growth and aging and for developing novel treatment strategies to reduce the morbidity and mortality associated with fragility fractures.

A genome wide linkage scan of metacarpal size and geometry in the Framingham Study

Bone geometry is a significant component of bone strength, and has a clinical utility in predicting fractures and quantifying bone loss. Bone geometry is known to have a substantial genetic component. We performed linkage analysis to identify chromosomal regions governing metacarpal bone geometry. A genome-wide scan (with a set of 615 markers with spacing of approximately 5.7 cM) was performed on 1,702 individuals from 330 extended families of the Framingham Study. Midshaft width was measured and several indices calculated, namely Metacarpal Cortical Thickness (MCT), Cortical Index (MCI), and Section Modulus (MZ), using digitized X-rays of 1,380 participants (men, n = 666, mean age 55.2 yr, women, n = 714, 55.5 yr). Metacarpals 2, 3, and 4 were averaged. Heritability was significant for all indices, ranging from 0.51 to 0.72. Linkage analysis of indices adjusted for age, age(2), and estrogen status in women, identified chromosomal regions 6p21, 9p21, 11q21-q22, and Xq26-Xq27, with LOD scores >2.0. Additional adjustment for smoking, height, and BMI, generally reduced the LOD scores. Finally, bivariate linkage analysis confirmed that a QTL on chr. 6 (51 cM) was shared by midshaft width and MZ (LOD = 2.40, adjusted for all covariates). Neither MCT nor MCI shared linkage loci with width or MZ. In conclusion, we have identified chromosomal regions potentially linked to bone geometry. Genes in these regions may regulate bone geometry via effects on body size. Identification and subsequent characterization of loci for bone geometry can further elucidate the genetic contributions to bone's resistance to stress.

Quantitative genetics of cortical bone mass in healthy 10-year-old children from the Fels Longitudinal Study

The genetic influences on bone mass likely change throughout the life span, but most genetic studies of bone mass regulation have focused on adults. There is, however, a growing awareness of the importance of genes influencing the acquisition of bone mass during childhood on lifelong bone health. The present investigation examines genetic influences on childhood bone mass by estimating the residual heritabilities of different measures of second metacarpal bone mass in a sample of 600 10-year-old participants from 144 families in the Fels Longitudinal Study. Bivariate quantitative genetic analyses were conducted to estimate genetic correlations between cortical bone mass measures, and measures of bone growth and development. Using a maximum likelihood-based variance components method for pedigree data, we found a residual heritability estimate of 0.71 for second metacarpal cortical index. Residual heritability estimates for individual measures of cortical bone (e.g., lateral cortical thickness, medial cortical thickness) ranged from 0.47 to 0.58, at this pre-pubertal childhood age. Low genetic correlations were found between cortical bone measures and both bone length and skeletal age. However, after Bonferonni adjustment for multiple testing, rho(G) was not significantly different from 0 for any of these pairs of traits. Results of this investigation provide evidence of significant genetic control over bone mass largely independent of maturation while bones are actively growing and before rapid accrual of bone that typically occurs during puberty.

Bone fragility: failure of periosteal apposition to compensate for increased endocortical resorption in postmenopausal women

The increase in bone fragility after menopause results from reduced periosteal bone formation and increased endocortical resorption. Women with highest remodeling had greatest loss of bone mass and estimated bone strength, whereas those with low remodeling lost less bone and maintained estimated bone strength.

INTRODUCTION

Bone loss from the inner (endocortical) surface contributes to bone fragility, whereas deposition of bone on the outer (periosteal) surface is believed to be an adaptive response to maintain resistance to bending.

MATERIALS AND METHODS

To test this hypothesis, changes in bone mass and estimated indices of bone geometry and strength of the one-third distal radius, bone turnover markers, and fracture incidence were measured annually in 821 women 30-89 years of age for 7.1 +/- 2.5 years. The analyses were made in 151 premenopausal women, 33 perimenopausal women, 279 postmenopausal women, and 72 postmenopausal women receiving hormone replacement therapy (HRT).

RESULTS

In premenopausal women, periosteal apposition increased the radius width, partly offsetting endocortical resorption; therefore, the estimated cortical thickness decreased. Outward displacement of the thinner cortex maintained bone mass and cortical area and increased estimated bending strength. Estimated endocortical resorption accelerated during perimenopause, whereas periosteal apposition decreased. Further cortical thinning occurred, but estimated bending strength was maintained by modest outward cortical displacement. Endocortical resorption accelerated further during the postmenopausal years, whereas periosteal apposition declined further; cortices thinned, but because outward displacement was minimal, estimated cortical area and bending strength now decreased. Women with highest remodeling had the greatest loss of bone mass and strength. Women with low remodeling lost less bone and maintained estimated bone strength. In HRT-treated women, loss of bone strength was partly prevented. These structural indices predicted incident fractures; a 1 SD lower section modulus doubled fracture risk.

CONCLUSIONS

Periosteal apposition does not increase after menopause to compensate for bone loss; it decreases. Bone fragility of osteoporosis is a consequence of reduced periosteal bone formation and increased endocortical resorption. Understanding the mechanisms of the age-related decline in periosteal apposition will identify new therapeutic targets. On the basis of our results, it may be speculated that the stimulation of periosteal apposition will increase bone width and improve skeletal strength.

Strong association between polymorphisms in ANKH locus and skeletal size traits

Loss of bone strength is the main determinant of bone fragility. Bone strength is directly dependent on bone size (BS). A substantial portion of BS variation is attributable to genetic effects. However, the list of genes and allelic variants involved in the determination of BS variation is far from being complete. Polymorphisms in the ANKH gene have been shown to be associated with radiographic hand BS-related phenotypes. The present study examined the possible association of the ANKH gene with skeletal size and shape in order to test the universality of the ANKH effect on BS traits. Our sample consisted of a total of 212 ethnically homogeneous nuclear families (743 individuals) of European origin. Each individual was measured for body height, weight, and several other anthropometrical measurements, and genotyped for nine polymorphic markers (the average heterozygosity level was 0.4). We observed significant associations with practically all the anthropometrical phenotypes studied. More specifically, we found associations with body weight and height, limb length (P</=0.001; promoter region). After adjustment for body height, we demonstrated the substantial association increase for biacromial breadth (P=0.0012; some 140 kb downstream from ANKH) and vertebral column length (P=0.0008; exons 2-7 region). The majority of the observed associations persisted even after correction for multiple testing. For the first time the reliable evidence in support of universality of ANKH gene polymorphisms effect on bone size was provided.

Variation in femoral length is associated with polymorphisms in RUNX2 gene

INTRODUCTION

Bone size is an important determinant of bone strength. Although it is well established that bone size traits are under the strong genetic control, genes involved in their determination are poorly characterized. The major objective of the present study was to test hypothesis of possible association between three RUNX2 SNP polymorphisms (rs2819858, rs1406846, rs2819854) and anthropometrical femoral length (FEML). In addition, the possibility of association between anthropometrical tibial length (TIBL) and stature and chosen RUNX2 polymorphisms was tested.

MATERIALS AND METHODS

The study was conducted on 265 nuclear families comprised of a total of 904 individuals. DNA samples were available for 705 individuals, belonging to 212 nuclear families. Three different transmission disequilibrium tests (TDTs), population-based and pedigree-based (PDT) association analyses were implemented in order to test the working hypothesis.

RESULTS

The results unambiguously and consistently demonstrated significant association for FEML regardless of the specific polymorphism tested and type of analysis implemented. The P values obtained by TDTs ranged between 0.0155 and 0.0007. The effect of RUNX2 polymorphisms was estimated to explain 1.9% of the total FEML variation after adjustment for sex and age. The data suggested that the strength of association between RUNX2 polymorphisms and FEML may be higher in females (P = 0.007) than in males (P = 0.046), according to PDT. Conversely, no reliable evidence of association between RUNX2 polymorphisms and either TIBL or stature was found.

CONCLUSIONS

For the first time, the evidence of association between RUNX2 polymorphisms and FEML was provided. The results of the present research contribute to the deeper understanding of the genetic architecture of femoral size and introduce the issues of site and sex dependency of the extent of RUNX2 effect. Further studies are required to confirm our findings, specifically focused on clinically oriented sites of skeleton, like femoral neck.

Linkage exclusion mapping with bone size in 79 Caucasian pedigrees

Bone size is an important risk factor of osteoporotic fractures and has strong genetic determination. However, genetic studies on bone size variation are relatively rare. In the present study, we conducted a linkage exclusion mapping for bone size variation on chromosomes 1, 4, 6, and 17 in 79 Caucasian pedigrees. For hip bone size variation, several genomic regions were excluded at effect sizes of 10% or greater, including regions of 61-77cM at 1p35-p34, 43-59cM at 4p15-p13, 1-59cM at 6p25-p21, 82-88cM at 17q23-q24, and 113-114cM at 17q25. For spine bone size, at effect sizes of 10% or greater, we excluded regions of 115-122cM at 1p31-p22, 136-141cM at 1p21, 207-260cM at 1q31-q42, 20-89cM at 4p16-q21, 11-21cM at 6p24-p23, and 1-6cM at 17p13. These results suggested that a number of candidate genes located in the excluded regions, such as the growth hormone (GH) gene, tumor necrosis factor-alpha (TNF-alpha) gene, and bone morphogenetic protein-3 (BMP3) gene, are unlikely to have a substantial effect on bone size variation in this Caucasian population.

Genetic and environmental correlations between age at menarche and bone mineral density at different skeletal sites

Low bone mineral density (BMD) is an important risk factor for osteoporotic fractures. Though previous studies have demonstrated that age at menarche (AAM) is phenotypically associated with BMD, the contributions of genetic and environmental factors to this association remain unknown. In this study, using variance decomposition analyses, we provided an accurate estimation of the genetic and environmental correlations between AAM and BMD in 2,667 Caucasian women from 512 pedigrees. After adjustment for significant covariates, we detected significant genetic correlations between AAM and BMD at the lumbar spine, femoral neck, and ultradistal radius (rho(G) = -0.1316, -0.1417, and -0.1137, respectively; all P < 0.01). However, all environmental correlations between AAM and BMD were nonsignificant (P > 0.05). We also generated a principal component factor for BMD (PC_BMD) and evaluated the relationship between this factor and AAM. The genetic and environmental correlations between PC_BMD and AAM (rho(P) = -0.0847, P < 0.001; rho(G) = -0.1737, P < 0.01; rho(E) = -0.0348, P > 0.05) were consistent with the results of BMD at the three skeletal sites and AAM. Our results confirmed the significant phenotypic association between BMD and AAM and for the first time suggested that this association is mainly attributable to shared genetic, rather than environmental, factors.

Association of ANKH gene polymorphisms with radiographic hand bone size and geometry in a Chuvasha population

We performed a family-based association study to test the hypothesis that genetic variation at the human orthologue of the mouse progressive ankylosis gene (ANKH) is involved in determining bone size (BS) and bone geometry (BG). The study population comprised 126 nuclear families with 574 adult Chuvashian individuals living in small villages in the Russian Federation. Quantitative bone traits were determined by analyzing plain hand radiographs. Familial correlations for all studied traits revealed a high degree of heritability in this ethnically homogeneous population. Three simple tandem repeat (STR) polymorphisms, one intragenic and two flanking markers, as well as six single nucleotide polymorphisms (SNPs) were tested. The SNPs were detected by re-sequencing experiments and covered ANKH exons with their flanking splice sites and the promoter region. We used three different transmission disequilibrium tests (TDTs) and obtained multiple significant association signals for all investigated bone traits. Alleles of several markers located at different positions of the ANKH locus, including the promoter, consistently revealed the association. The bone traits tested are closely related to bone fragility suggesting a role for ANKH in osteoporosis.

Genetic epidemiology of skeletal system aging in apparently healthy human population

The study of our team was driven by a clinical problem of age-dependent chronic degenerative disease of skeleton that includes osteoporosis (OP) and osteoarthritis (OA)-related phenotypes. The major aims of the study included evaluation of the putative genetic factors determining the rate and pattern of the bone and cartilage loss and identification of the specific genes involved in this process. In addition, we examined genetic effects on circulating molecular factors involved in bone and cartilage metabolism. The skeletal phenotypes were assessed from hand radiographs, in total on about 1200 individuals belonging to ethnically homogeneous nuclear and complex three-generational pedigrees of European origin. The results obtained until now can be divided into three sections: (1) genetic analysis of bone mass/size/geometry characteristics (OP) and traits related to hand OA; (2) pedigree-based investigation of circulating levels of calciotropic hormones, growth factors, cytokines, and biochemical indices of bone and cartilage remodelling; (3) linkage and linkage disequilibrium study of several candidate genes, such as estrogen receptor alpha, collagen type I alpha 1, genes related to extracellular inorganic pyrophosphate transport and OP/OA phenotypes, including biochemical variables. The study provides compelling evidence to suggest strong involvement of the genetic factors in determination of variation of the majority of the examined OP- and OA-related phenotypes.

A follow-up linkage study for bone size variation in an extended sample

Bone size, which has strong genetic determination, is an important determinant of bone strength and a risk factor of osteoporotic fractures. We previously reported an approximately 10-cm genome-wide linkage scan in 630 subjects from 53 US Caucasian pedigrees. The strongest evidence of linkage was obtained on chromosome 17q22 near the marker D17S787, with a two-point LOD score of 3.98 and a multipoint maximum LOD score (MLS) of 3.01. Additionally, suggestive linkages (1.54 < MLS < 2.83) were found at the other four chromosomal regions. In the present study, with an attempt to further examine our previous findings, we perform a follow-up linkage analysis in an expanded sample of 79 pedigrees with 1816 subjects. The total sample contains >80,000 informative relative pairs for linkage analyses, including 3846 sib pairs. Fifteen markers covering the above five promising regions are genotyped, narrowing the average genomic distance from approximately 10 to 5 cm. In the total 79 pedigrees, support of linkage was achieved for the wrist bone size at 17q22 with a two-point LOD score of 2.27 (P = 0.0006) and MLS of 1.78 (P = 0.002). The genomic region 17q22 includes COL1A1, a strong candidate gene that is significantly associated with osteoporotic fracture risk. Our data suggest that this region is promising for further exploratory studies.

Mapping quantitative trait loci for vertebral trabecular bone volume fraction and microarchitecture in mice

BMD, which reflects both cortical and cancellous bone, has been shown to be highly heritable; however, little is known about the specific genetic factors regulating trabecular bone. Genome-wide linkage analysis of vertebral trabecular bone traits in 914 adult female mice from the F2 intercross of C57BL/6J and C3H/HeJ inbred strains revealed a pattern of genetic regulation derived from 13 autosomes, with 5-13 QTLs associated with each of the traits. Ultimately, identification of genes that regulate trabecular bone traits may yield important information regarding mechanisms that regulate mechanical integrity of the skeleton.

INTRODUCTION

Both cortical and cancellous bone influence the mechanical integrity of the skeleton, with the relative contribution of each varying with skeletal site. Whereas areal BMD, which reflects both cortical and cancellous bone, has been shown to be highly heritable, little is known about the genetic determinants of trabecular bone density and architecture.

MATERIALS AND METHODS

To identify heritable determinants of vertebral trabecular bone traits, we evaluated the fifth lumbar vertebra from 914 adult female mice from the F2 intercross of C57BL/6J (B6) and C3H/HeJ (C3H) progenitor strains. High-resolution microCT was used to assess total volume (TV), bone volume (BV), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), separation (Tb.Sp), and number (Tb.N) of the trabecular bone in the vertebral body in the progenitors (n = 8/strain) and female B6C3H-F2 progeny (n = 914). Genomic DNA from F2 progeny was screened for 118 PCR-based markers discriminating B6 and C3H alleles on all 19 autosomes.

RESULTS AND CONCLUSIONS

Despite having a slightly larger trabecular bone compartment, C3H progenitors had dramatically lower vertebral trabecular BV/TV (-53%) and Tb.N (-40%) and higher Tb.Sp (71%) compared with B6 progenitors (p < 0.001 for all). Genome-wide quantitative trait analysis revealed a pattern of genetic regulation derived from 13 autosomes, with 5-13 quantitative trait loci (QTLs) associated with each of the vertebral trabecular bone traits, exhibiting adjusted LOD scores ranging from 3.1 to 14.4. The variance explained in the F2 population by each of the individual QTL after adjusting for contributions from other QTLs ranged from 0.8% to 5.9%. Taken together, the QTLs explained 22-33% of the variance of the vertebral traits in the F2 population. In conclusion, we observed a complex pattern of genetic regulation for vertebral trabecular bone volume fraction and microarchitecture using the F2 intercross of the C57BL/6J and C3H/HeJ inbred mouse strains and identified a number of QTLs, some of which are distinct from those that were previously identified for total femoral and vertebral BMD. Identification of genes that regulate trabecular bone traits may ultimately yield important information regarding the mechanisms that regulate the acquisition and maintenance of mechanical integrity of the skeleton.

Genetic variation of circulating leptin is involved in genetic variation of hand bone size and geometry

Leptin is secreted primarily by the adipocytes and plays an important role in the regulation of food intake and energy expenditure. In addition to its adipostatic function, it has been demonstrated that leptin directly enhances stromal cell differentiation to osteoblasts, and since such precursor cells are potential targets for leptin, the latter could possibly mediate the relationship between obesity and bone mass and size. To address this question, we studied phenotypic and genetic correlations between the circulating levels of leptin and hand bone size (BS) and geometry (BG) of the radiographic hand in a healthy and ethnically homogeneous sample of pedigrees. We also attempted to evaluate to what extent potential leptin/BS/BG correlations are modified by an individual's obesity traits, specifically his/her BMI. Our research has shown that leptin, BMI and the corresponding bone measures are clearly inherited traits (0.46+/-0.11, 0.35+/-0.16, 0.62+/-0.12 and 0.51+/-0.09, respectively). The bivariate variance component analysis revealed very strong and significant genetic and environmental correlations between circulating leptin and BMI ( r(G)=0.86+/-0.09, r(E)=0.75+/-0.05, P<0.001). Furthermore, genetic correlations between leptin and hand bone characteristics proved inverse and statistically significant ( r(G)=-0.35+/-0.01 and -0.45+/-0.10 for BS and BG, respectively), while corresponding environmental correlations were low ( r(E)=-0.14+/-0.15 and -0.07+/-0.14) and they could be constrained to zero without significant deterioration of the model fit to the data ( P>0.10). However, despite the extremely strong relationship between leptin and BMI, we failed to detect phenotypic or genetic correlations between BMI and our two hand bone measures. Thus our study provided evidence that plasma leptin levels may be statistically significant predictor of hand bone size and geometry, and may play a physiological role in maintaining bone mass as well as in regulation of hand bone proportions.