Family history of osteoporosis and bone mineral density at the axial skeleton: the Rancho Bernardo Study

Knowledge, Attitudes, Practices, and Awareness Levels Among Indian Postmenopausal Women About Osteoporosis and Its Relationship With Sociodemographic Factors: A Cross-Sectional Study From Northern India

Background Osteoporosis is a silent disease and can be prevented by providing correct and appropriate information to the individuals at risk. Therefore, we aim to find out the levels of knowledge, attitudes, and behaviors of postmenopausal women, the highest-risk group. Methods Between May 2021 and December 2023, a cross-sectional study was done in the Military Hospital in Ambala, India, in 1326 postmenopausal women of age between 45 and 70 years who visited the outpatient department of orthopedics and who previously had a measure of bone mineral density (BMD) or estimation of BMD. All patients participating in the study received a questionnaire that assessed the level of knowledge, attitudes, and behaviors related to osteoporosis. The Osteoporosis Knowledge Assessment Tool (OKAT) was used to assess these parameters. Results The mean age was 60±3.1 years. The mean score for osteoporosis awareness was 6/20 points. A total of 983 (73.13%) had no knowledge about osteoporosis, and 221 (16.66%) had higher knowledge. Knowledge about osteoporosis was low with a mean knowledge score of 7.44±3.16 and a median of 7.2. It was found that those who graduated had some knowledge regarding osteoporosis with the help of either a hospital staff or a family member who had a history of osteoporosis. Conclusions Even among postmenopausal women who know they are at risk and should have BMD, knowledge, attitudes, and behaviors about osteoporosis were found to be quite low. In addition, education and mass communications are needed to increase awareness among women of this age about improving bone health.

Bone mass accrual in children

PURPOSE OF REVIEW

Bone accrual during childhood and adolescence is critical for the attainment of peak bone mass and is a major contributing factor towards osteoporosis in later life. Bone mass accrual is influenced by nonmodifiable factors, such as genetics, sex, race, ethnicity, and puberty, as well as modifiable factors, such as physical activity and diet. Recent progress in bone imaging has allowed clinicians and researchers to better measure the morphology, density, and strength of the growing skeleton, thereby encompassing key characteristics of peak bone strength. In this review, the patterning of bone accrual and contributors to these changes will be described, as well as new techniques assessing bone mass and strength in pediatric research and clinical settings.

RECENT FINDINGS

This review discusses factors influencing peak bone mass attainment and techniques used to assess the human skeleton.

SUMMARY

The rate of bone accrual and the magnitude of peak bone mass attainment occurs in specific patterns varying by sex, race, ethnicity, longitudinal growth, and body composition. Physical activity, diet, and nutritional status impact these processes. There is a need for longitudinal studies utilizing novel imaging modalities to unveil factors involved in the attainment and maintenance of peak bone strength.

Plastin 3 in health and disease: a matter of balance

For a long time, PLS3 (plastin 3, also known as T-plastin or fimbrin) has been considered a rather inconspicuous protein, involved in F-actin-binding and -bundling. However, in recent years, a plethora of discoveries have turned PLS3 into a highly interesting protein involved in many cellular processes, signaling pathways, and diseases. PLS3 is localized on the X-chromosome, but shows sex-specific, inter-individual and tissue-specific expression variability pointing towards skewed X-inactivation. PLS3 is expressed in all solid tissues but usually not in hematopoietic cells. When escaping X-inactivation, PLS3 triggers a plethora of different types of cancers. Elevated PLS3 levels are considered a prognostic biomarker for cancer and refractory response to therapies. When it is knocked out or mutated in humans and mice, it causes osteoporosis with bone fractures; it is the only protein involved in actin dynamics responsible for osteoporosis. Instead, when PLS3 is upregulated, it acts as a highly protective SMN-independent modifier in spinal muscular atrophy (SMA). Here, it seems to counteract reduced F-actin levels by restoring impaired endocytosis and disturbed calcium homeostasis caused by reduced SMN levels. In contrast, an upregulation of PLS3 on wild-type level might cause osteoarthritis. This emphasizes that the amount of PLS3 in our cells must be precisely balanced; both too much and too little can be detrimental. Actin-dynamics, regulated by PLS3 among others, are crucial in a lot of cellular processes including endocytosis, cell migration, axonal growth, neurotransmission, translation, and others. Also, PLS3 levels influence the infection with different bacteria, mycosis, and other pathogens.

Prevalence and risk factors for osteoporotic fracture among adults with comorbidities in Al-Ahsaa, Saudi Arabia

Background and Aims

Little is known about the prevalence of osteoporotic fracture, its sociodemographic correlates, and its comorbid conditions among the adult population of the Kingdome of Saudi Arabia (KSA). Hence, the present work aimed to assess the prevalence of adults at high risk of osteoporotic fracture in the presence of its known risk factors. As well, to determine the most commonly associated comorbidities of osteoporosis in Saudi Arabia.

Methods

A cross-sectional study was performed among 518 Saudi adults aged over 45 years in Al-Ahsaa city, KSA. The Arabic version of the fracture risk assessment FRAX without bone mineral density (BMD) was presented in an online questionnaire.

Results

The 10-year risk for major osteoporotic fracture was found in 50.81% of the participants; 23.48% of them were at high risk and 25.71% at moderate risk. Also, 26.27% of the respondents were at high risk of hip fracture. Significant correlates of osteoporotic fractures included female gender (P = 0.003), old age (P = 0.000), age at menopause (P = 0.000), low body mass index (BMI; P = 0.000), previous fracture (P = 0.000), alcohol consumption (P = 0.000), positive family history (P = 0.000), corticosteroids (P = 0.000), rheumatoid arthritis (P = 0.000), thyroid hyperactivity (P = 0.000), gonadal insufficiency (P = 0.000), chronic liver disease (P = 0.000), nutritional, or gestational disease (P = 0.000).

Conclusion

More than a third of the surveyed population had osteoporosis, which was associated with many sociodemographic and clinical characteristics. Therefore, early interventions for osteoporosis and the prevention of other comorbidities may improve the outcome of osteoporosis.

Evolutionary Perspectives on the Developing Skeleton and Implications for Lifelong Health

Osteoporosis is a significant cause of morbidity and mortality in contemporary populations. This common disease of aging results from a state of bone fragility that occurs with low bone mass and loss of bone quality. Osteoporosis is thought to have origins in childhood. During growth and development, there are rapid gains in bone dimensions, mass, and strength. Peak bone mass is attained in young adulthood, well after the cessation of linear growth, and is a major determinant of osteoporosis later in life. Here we discuss the evolutionary implications of osteoporosis as a disease with developmental origins that is shaped by the interaction among genes, behavior, health status, and the environment during the attainment of peak bone mass. Studies of contemporary populations show that growth, body composition, sexual maturation, physical activity, nutritional status, and dietary intake are determinants of childhood bone accretion, and provide context for interpreting bone strength and osteoporosis in skeletal populations. Studies of skeletal populations demonstrate the role of subsistence strategies, social context, and occupation in the development of skeletal strength. Comparisons of contemporary living populations and archeological skeletal populations suggest declines in bone density and strength that have been occurring since the Pleistocene. Aspects of western lifestyles carry implications for optimal peak bone mass attainment and lifelong skeletal health, from increased longevity to circumstances during development such as obesity and sedentism. In light of these considerations, osteoporosis is a disease of contemporary human evolution and evolutionary perspectives provide a key lens for interpreting the changing global patterns of osteoporosis in human health.

Investigation of Comorbidity, Trauma History, and Osteoporotic Fractures in the Postmenopausal Population: A Nationwide, Observational, and Cross-Sectional Study of Korean Orthopedic Outpatient Clinics

Study Design

A nationwide, observational, and cross-sectional study targeting postmenopausal patients from 62 orthopedic outpatient clinics in Korea between October 2010 and February 2011.

Purpose

This study was carried out to investigate comorbidity, trauma history, and the status of osteoporotic fracture treatment in Korean postmenopausal women.

Overview of Literature

There has been little reports on the comorbidity, family history, trauma history, and treatment status of osteoporotic fractures in patients visiting the orthopedic outpatient clinics in Korea.

Methods

A total of 1,255 postmenopausal women between the ages of 50 and 80 years were enrolled in the study and the population distribution was reflected by region. Comorbidity, familial history of osteoporosis, familial history of osteoporotic fracture, history of falls, and status of osteoporotic fracture management were evaluated using an interview and questionnaire. The relationship between family history of osteoporosis and bone mineral density was analyzed.

Results

A number of patients (23%) had a family history of osteoporosis and 16.5% had a family history of fractures. Most (64.7%) of the patients had one or more comorbidities, including 58.8% exhibiting a chronic disease and 16.4% suffering from diseases that restrict exercise or walking. The results of the questionnaire indicated that 21.8% of these fracture patients had experienced a fracture previously and that the most common type of fracture was that of the spine. Lumbar spine bone mineral density was found to be lower in the presence of family history of osteoporosis.

Conclusions

Postmenopausal women are liable to have osteoporotic fractures due to the high prevalence of osteoporosis, a history of falling, and the comorbidity with diseases that restrict ambulation. A better understanding of postmenopausal women in the orthopedic outpatient settings is important to the management of osteoporotic fractures.

Genome-scale Capture C promoter interactions implicate effector genes at GWAS loci for bone mineral density

Osteoporosis is a devastating disease with an essential genetic component. GWAS have discovered genetic signals robustly associated with bone mineral density (BMD), but not the precise localization of effector genes. Here, we carry out physical and direct variant to gene mapping in human mesenchymal progenitor cell-derived osteoblasts employing a massively parallel, high resolution Capture C based method in order to simultaneously characterize the genome-wide interactions of all human promoters. By intersecting our Capture C and ATAC-seq data, we observe consistent contacts between candidate causal variants and putative target gene promoters in open chromatin for ~ 17% of the 273 BMD loci investigated. Knockdown of two novel implicated genes, ING3 at ‘CPED1-WNT16’ and EPDR1 at ‘STARD3NL’, inhibits osteoblastogenesis, while promoting adipogenesis. This approach therefore aids target discovery in osteoporosis, here on the example of two relevant genes involved in the fate determination of mesenchymal progenitors, and can be applied to other common genetic diseases.

GWAS have identified numerous genetic loci for bone mineral density (BMD) and fracture risk. Here, the authors map these variants to putative target genes using ATAC-seq and Capture C of human osteoblasts and confirm ING3 and EPDR1 as BMD genes in in vitro osteoblast differentiation experiments.

Single limb immobilization model for bone loss from unloading

Hindlimb suspension is the most used model for inducing bone loss from unloading but requires a separate ground control group. This control group cannot be used for genetic studies involving outbred mice. In this study, we evaluated a single limb immobilization (SLI) model for inducing bone loss from unloading, with the contralateral limb from the same animal used as a control. Male 10-week old C57Bl/6J mice had one limb immobilized for one, two, or three weeks. Subsequently, an additional group of male 16-week old C57Bl/6J mice had one limb immobilized for three weeks. SLI resulted in decreased tibial trabecular BV/TV, Tb Th, and Tb N compared to contralateral limbs in young mice. Femoral trabecular BV/TV, Tb Th, Tb N, and femoral cortical area fraction were also decreased. Mechanical properties were not affected after three weeks. In adult mice, femoral trabecular BV/TV, Tb Th, and Tb N were decreased. Femoral stiffness, ultimate stress, and Young's modulus were decreased. Bone properties decreased by SLI were also decreased by hindlimb suspension previously. The results suggest SLI can be an effective model for inducing bone loss in growing and adult mice after three weeks of immobilization.

Night shift work and osteoporosis: evidence and hypothesis

Osteoporosis is an important public health problem worldwide. Among the countries with a very high population risk of fractures, there are those with the highest level of economic development. Osteoporotic fractures are the main cause of disability among elderly people, and the resultant disabilities require particularly large financial support associated not only with the direct treatment of the fracture but also with the necessity for long-term rehabilitation and care for the disabled person. Many well-established factors can have impact on bone mass and fracture risk. Recently, it has been hypothesized that working during nighttime which leads to endocrine disorders may have an indirect impact on bone physiology among night shift workers. Therefore, it can be presumed that the night shift work may contribute to the etiology of osteoporosis. The aim of our work was to make a review of the epidemiological evidence on the association between night shift work and bone mineral density or fracture risk as well as to discuss the potential biological mechanisms linking the work under this system with the development of osteoporosis. We have identified only four studies investigating the association between system of work and bone mineral density or fracture risk among workers. The findings of three out of four studies support the hypothesis. None of the studies has investigated a potential relationship between night shift work and bone turnover markers. Given that there have been no epidemiological studies in European countries that would concern working populations and the noticeable difference in the risk of osteoporosis between communities, further studies are warranted to elucidate the problem. It is presumed that further in-depth studies will not only identify the underlying factors of the disease but also contribute to developing guidelines for policy makers and employers for primary prevention of osteoporosis in workplace.

Association of interleukin-6 (rs1800796) but not transforming growth factor beta 1 (rs1800469) with serum calcium levels in osteoporotic patients

BACKGROUND

Osteoporosis is a multifactorial disease with a strong genetic influence. Recent studies have demonstrated that cytokines, such as TGF-β1 and interleukin 6 (IL-6) play complex roles in the normal bone metabolism and pathophysiology of osteoporosis. Here, we investigated the roles of 2 polymorphisms mapping to the promoters of TGF-β1and IL-6 genes on the genetic susceptibility to osteoporosis as well as calcium and vitamin D levels.

METHODS

A cohort of 297 elderly participants in northern Iran comprising 181 osteoporotic patients (mean age ± SD, 68.36 ± 7.21 years) and 116 unrelated healthy controls (mean age ± SD, 64 ± 5.44 years) was studied for TGF-β1(C-509T) and IL-6 (G-634C) polymorphisms using PCR-RFLP method.

RESULTS

A significant relationship was observed between calcium level and IL-6 genotypes in osteoporotic males (P = 0.011) and females (P = 0.020). No significant differences were observed between osteoporotic and control groups with respect to allele frequency or genotype distribution based on the 2 selected polymorphisms under different genetic models. The results remained the same after comparing the BMD values of either the femur neck or lumbar spine with the genotypes of the elderly men and women when analyzed separately.

CONCLUSION

IL-6 genotype influences serum calcium levels in osteoporotic patients. The lack of association between the common genetic variations of TGF-β1 and IL-6 genes, and BMD highlights the complex genetic background of osteoporosis in the north of Iran.

Early Detection and Prevention of Osteoporosis Among Pre- and Postmenopausal Women in Saudi Arabia

Osteoporosis is difficult to treat and is still incurable, and thus prevention is critically important. The aim of this study was to find out the high-risk women for osteoporosis and to correlate their bone mineral density (BMD) with their investigated risk factors. Cross-sectional design was used and it was conducted among 200 pre- and postmenopausal Saudi women. The study documented that postmenopausal females had high prevalence of osteopenia and majority of them had low serum calcium. Significant correlation was found between low BMD and family history of osteoporosis; increased BMD was seen in women, who consumed calcium-rich foods, exposure to sun light, and longer fertility period. Majority of the women 94.5% had inadequate knowledge on preventive measures of osteoporosis. The high prevalence of osteopenia in postmenopausal women indicates the ultimate importance of early intervention to prevent development of osteoporosis in later life.

Total and lean fish intake is positively associated with bone mineral density in older women in the community-based Hordaland Health Study

PURPOSE

Fish is a source of various nutrients beneficial for bone health, but few studies have investigated the association between bone mineral density (BMD) and fish consumption. Thus, the aim was to investigate the relationship between total fish intake and BMD and between both lean and fatty fish intake and BMD.

METHOD

These cross-sectional analyses include 4656 participants in the Hordaland Health Study, a community-based study conducted in 1997-1999. The study includes two birth cohorts of men and women from Hordaland county (Norway) born in 1950-1951 and 1925-1927. BMD was measured by dual-energy X-ray absorptiometry and dietary intake was obtained from a semi-quantitative food-frequency questionnaire.

RESULTS

The average total fish intake was 33 ± 18 g/1000 kcal and was primarily lean fish. Older women had significantly lower BMD than older men and middle-aged men and women. In older women, total and lean fish intake (50 g/1000 kcal) was significantly and positively associated with BMD also after multivariate adjustments (β-coefficient 0.018, p = 0.017 and 0.026, p = 0.021).

CONCLUSION

A high intake of fish, in particular lean fish, was positively associated with BMD in older women. No association between intake of fatty fish and BMD was found in either of the age and sex groups.

Primary Osteoporosis in Young Adults: Genetic Basis and Identification of Novel Variants in Causal Genes

Genetic determinants contribute to osteoporosis and enhance the risk of fracture. Genomewide association studies of unselected population-based individuals or families have identified polymorphisms in several genes related to low bone density, but not in osteoporotic patients with Z-score < -2.0 SD with fragility fracture(s). The aim of this study was to determine the causal genes of idiopathic osteoporosis in the adulthood. Also, we used next-generation sequencing of candidate genes in a cohort of 123 young or middle-aged adults with idiopathic osteoporosis. All patients were included if they had a low bone mineral density (Z-score < -2 SD), a diagnosis before age 55 years (mean ± SD, 48.4 ± 10.6 years; mean ± SD age at first fracture, 30.4 ± 17.4 years) and fracture or not. We found that 11 patients carried rare or novel variants in COL1A2 (n = 4), PLS3 (n = 2), WNT1 (n = 4), or DKK1 (n = 1). We showed a high prevalence of pathogenic variants in LRP5: 22 patients (17.8%) had the p.Val667Met variant, including three at the homozygous level and 16 (13%) carrying a novel or very rare variant. Functional analysis revealed that the LRP5 missense variants resulted in reduced luciferase activity, which indicates reduced activation of canonical WNT signaling. The clinical phenotype of patients carrying causal gene variants was indistinguishable. In conclusion, molecular screening of young osteoporotic adults revealed several variants and could be useful to characterize susceptibility genes for personalizing treatment, in particular for the new anabolic drugs.© 2017 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Prevalence and Risk Factors of Osteoporosis Among Jordanian Postmenopausal Women Attending the National Center for Diabetes, Endocrinology and Genetics in Jordan

To assess the prevalence of osteoporosis and osteopenia among Jordanian postmenopausal women attending the National Center for Diabetes, Endocrinology, and Genetics (NCDEG), and to determine the potential associated risk factors. A cross-sectional study was conducted at (NCDEG) in Amman, Jordan. A total of 1079 Jordanian postmenopausal women aged between 45 and 84 years were included in this study that was conducted during the period between April 2013 and December 2014. All patients underwent bone mineral density measurement through dual-energy X-ray absorptiometry (DEXA) scan. DEXA scan was interpreted in terms of T score as per World Health Organization guidelines. The overall prevalence of osteoporosis and osteopenia was 37.5% and 44.6%, respectively. The maximum prevalence of osteoporosis was observed at the lumbar spine (32.4%) followed by the left femoral neck (14.4%), while the maximum prevalence of osteopenia was observed at the left femoral neck (56.1%) followed by the lumbar spine (41.3%). Patients with longer menopausal duration, normal or overweight body mass index, high parity, physical inactivity, positive family history of osteoporosis, inadequate sun exposure, high daily caffeine intake, low daily calcium intake, and delay in the age of menarche were all positively associated with osteoporosis. On the other hand, women with type 2 diabetes mellitus had lower risk of osteoporosis. There is a high prevalence of osteoporosis and osteopenia among Jordanian postmenopausal women. Necessary steps are needed for more public education and a wider dissemination of information about osteoporosis and its prevention.

A Genomewide Association Study Identifies Two Sex-Specific Loci, at SPTB and IZUMO3, Influencing Pediatric Bone Mineral Density at Multiple Skeletal Sites

Failure to achieve optimal bone mineral accretion during childhood and adolescence results in subsequent suboptimal peak bone mass, contributing to osteoporosis risk later in life. To identify novel genetic factors that influence pediatric bone mass at discrete skeletal sites, we performed a sex-stratified genomewide association study of areal bone mineral density (BMD) measured by dual-energy X-ray absorptiometry at the 1/3 distal radius, spine, total hip, and femoral neck in a cohort of 933 healthy European American children. We took forward signals with p < 5 × 10-5 and minor allele frequency (MAF) >5% into an independent cohort of 486 European American children in search of replication. In doing so, we identified five loci that achieved genome wide significance in the combined cohorts (nearest genes: CPED1, IZUMO3, RBFOX1, SPBT, and TBPL2), of which the last four were novel and two were sex-specific (SPTB in females and IZUMO3 in males), with all of them yielding associations that were particularly strong at a specific skeletal site. Annotation of potential regulatory function, expression quantitative trait loci (eQTL) effects and pathway analyses identified several potential target genes at these associated loci. This study highlights the importance of sex-stratified analyses at discrete skeletal sites during the critical period of bone accrual, and identifies novel loci for further functional follow-up to pinpoint key genes and better understand the regulation of bone development in children. © 2017 American Society for Bone and Mineral Research.

Genome-wide QTL mapping results for regional DXA body composition and bone mineral density traits in pigs

Abstract. In a previous study, genome-wide mapping of quantitative trait loci (QTL) for five body composition traits, three bone mineral traits and live weight was performed using whole-body dual-energy X-ray absorptiometry (DXA) data. Since QTL for bone mineral traits were rare, the current study aimed to clarify whether the mapping results were influenced by the analysed body regions. Thus, the same material (551 pigs) and methods as in the whole-body QTL mapping study were used. However, for evaluation of the DXA scans, we manually defined two body regions: (i) from the last ribs to the pelvis (A) and (ii) including the pelvis and the hind limbs (P). Since live weight was not affected by the regional analysis, it was omitted from the QTL mapping design. Our results show an overall high consistency of mapping results especially for body composition traits. Two thirds of the initial whole-body QTL are significant for both A and P. Possible causes for the still low number of bone mineral QTL and the lower consistency found for these traits are discussed. For body composition traits, the data presented here show high genome-wide Pearson correlations between mapping results that are based on DXA scans with the time-saving whole-body standard setting and mapping results for DXA data that were obtained by time-consuming manual definition of the regions of interest. However, our results also suggest that whole-body or regional DXA scans might generally be less suitable for mapping of bone mineral traits in pigs. An analysis of single reference bones could be more useful.

Associations between serum vitamin E concentration and bone mineral density in the US elderly population

Mixed findings regarding effects of vitamin E on bone metabolism existed. We were the first to find a negative association between serum α-tocopherol concentration and bone mineral density in the US elderly population. Using vitamin E supplement as α-tocopherol to promote bone health was not warranted at this time.

INTRODUCTION

The aim of the study is to examine the associations between serum vitamin E (α-tocopherol and γ-tocopherol) status and bone mineral density (BMD) among the US elderly population.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) 2005-2006. This cross-sectional study finally included 989 subjects who were not having liver diseases, kidney diseases, rheumatoid arthritis, or cancers; were not treated for osteoporosis; and were not taking steroids or female hormones. Multivariable linear regression models were employed to examine the associations between serum vitamin E (α-tocopherol and γ-tocopherol) concentration and BMDs of total spine and femoral neck after adjusting for covariates and potential confounders.

RESULTS

Significant differences in serum α-tocopherol and γ-tocopherol levels, dietary intake of vitamin E as α-tocopherol, and BMDs of total spine and femoral neck were presented between male and female participants. Serum α-tocopherol and γ-tocopherol concentrations were found to be inversely correlated (r = -0.169, P < 0.001). In univariable linear models, significant negative associations between serum α-tocopherol and both total spine BMD (β = -0.0014, P = 0.002) and femoral neck BMD (β = -0.0017, P < 0.001) were found. Accounting for covariates, serum α-tocopherol level was negatively associated with femoral neck BMD (β = -0.0007, P = 0.028).

CONCLUSIONS

This study found a negative association between serum α-tocopherol concentration and femoral neck BMD in the US elderly population, suggesting a harmful effect of α-tocopherol on bone health. Future studies are warranted to further examine the dose-response relationships between individual vitamin E isomers and bone metabolism.

Musculoskeletal profile of middle-aged Ving Tsun Chinese martial art practitioners: A cross-sectional study

This cross-sectional exploratory study aimed to quantify and compare the axial and appendicular bone mineral density (BMD), muscle mass, and muscle strength of middle-aged practitioners of Ving Tsun (VT; a hard-style Chinese martial art) with those of nonpractitioners.Eighteen VT practitioners (mean age ± standard deviation = 51.8 ± 17.7 years; 12 men and six women) and 36 active controls (mean age ± standard deviation = 58.7 ± 11.0 years; 18 men and 18 women) participated in the study. All participants underwent a 1-day battery of musculoskeletal examinations. The BMD of the total radius, total hip, femoral neck, and lumbar spine was measured using dual-energy X-ray absorptiometry, as was the lean mass of the arm, leg, and trunk. Muscle strength of the upper and lower limbs was assessed using a Jamar dynamometer and an isokinetic dynamometer at 60°/second, respectively.VT-trained participants had a 11.5% higher total radius BMD (P = 0.023), a 17.8% higher leg lean mass (P = 0.014), a 56.4% higher isokinetic body weight-adjusted peak torque of the knee extensors (P < 0.001), a 60.8% higher isokinetic body weight-adjusted peak torque of knee flexors (P < 0.001), and a 31.4% shorter time to reach peak torque in the knee flexors (P = 0.001) than the active controls. No significant differences were found in any of the other musculoskeletal outcomes between the 2 groups (P > 0.05).Middle-aged VT practitioners displayed a higher total radius BMD and leg lean mass and better knee extensor and flexor muscular performances than their healthy active counterparts. Healthcare professionals may consider using this alternative method of training to improve the musculoskeletal health of middle-aged adults.

Osteoporosis and Periodontitis

Osteoporosis and periodontitis are both diseases characterized by bone resorption. Osteoporosis features systemic degenerative bone loss that leads to loss of skeletal cancellous microstructure and subsequent fracture, whereas periodontitis involves local inflammatory bone loss, following an infectious breach of the alveolar cortical bone, and it may result in tooth loss. Most cross-sectional studies have confirmed the association of osteoporosis and periodontitis primarily on radiographic measurements and to a lesser degree on clinical parameters. Multiple shared risk factors include age, genetics, hormonal change, smoking, as well as calcium and vitamin D deficiency. Both diseases could also be risk factors for each other and have a mutual impact that requires concomitant management. Suggested mechanisms underlying the linkage are disruption of the homeostasis concerning bone remodeling, hormonal balance, and inflammation resolution. A mutual interventional approach is emerging with complex treatment interactions. Prevention and management of both diseases require interdisciplinary approaches and warrants future well-controlled longitudinal and interventional studies for evidence-based clinical guidelines.

The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations

Lifestyle choices influence 20-40 % of adult peak bone mass. Therefore, optimization of lifestyle factors known to influence peak bone mass and strength is an important strategy aimed at reducing risk of osteoporosis or low bone mass later in life. The National Osteoporosis Foundation has issued this scientific statement to provide evidence-based guidance and a national implementation strategy for the purpose of helping individuals achieve maximal peak bone mass early in life. In this scientific statement, we (1) report the results of an evidence-based review of the literature since 2000 on factors that influence achieving the full genetic potential for skeletal mass; (2) recommend lifestyle choices that promote maximal bone health throughout the lifespan; (3) outline a research agenda to address current gaps; and (4) identify implementation strategies. We conducted a systematic review of the role of individual nutrients, food patterns, special issues, contraceptives, and physical activity on bone mass and strength development in youth. An evidence grading system was applied to describe the strength of available evidence on these individual modifiable lifestyle factors that may (or may not) influence the development of peak bone mass (Table 1). A summary of the grades for each of these factors is given below. We describe the underpinning biology of these relationships as well as other factors for which a systematic review approach was not possible. Articles published since 2000, all of which followed the report by Heaney et al. [1] published in that year, were considered for this scientific statement. This current review is a systematic update of the previous review conducted by the National Osteoporosis Foundation [1]. [Table: see text] Considering the evidence-based literature review, we recommend lifestyle choices that promote maximal bone health from childhood through young to late adolescence and outline a research agenda to address current gaps in knowledge. The best evidence (grade A) is available for positive effects of calcium intake and physical activity, especially during the late childhood and peripubertal years-a critical period for bone accretion. Good evidence is also available for a role of vitamin D and dairy consumption and a detriment of DMPA injections. However, more rigorous trial data on many other lifestyle choices are needed and this need is outlined in our research agenda. Implementation strategies for lifestyle modifications to promote development of peak bone mass and strength within one's genetic potential require a multisectored (i.e., family, schools, healthcare systems) approach.

Association between the ACE gene I/D polymorphism and osteoporosis in a Turkish population

PURPOSE

The purpose of this study was to assess the relationship between osteoporosis and the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in a Turkish population.

METHODS

The study group consisted of 238 unrelated women with osteoporosis and 124 unrelated healthy female controls. All participants, patients and healthy controls, were of Turkish origin from the central region of Turkey. Genomic DNA was isolated from whole venous blood samples using a commercial DNA isolation kit. The ACE gene I/D polymorphism was analysed by polymerase chain reaction and gel electrophoresis.

RESULTS

Frequencies of the DD, ID and II genotypes in the patients were 44.5, 41.2 and 14.3 %, and in the controls they were 25.0, 51.6 and 23.4 %, respectively. A significant difference was observed between patients and controls according to genotype frequency (p=0.001). D and I allele frequencies of the I/D polymorphism were 65.1 and 34.9 % in the patient group and 50.8 and 49.2 % in the control group, respectively (p<0.001).

CONCLUSION

The ACE gene I/D polymorphism could be a genetic factor associated with osteoporosis.

A biomechanical sorting of clinical risk factors affecting osteoporotic hip fracture

Osteoporotic fracture has been found associated with many clinical risk factors, and the associations have been explored dominantly by evidence-based and case-control approaches. The major challenges emerging from the studies are the large number of the risk factors, the difficulty in quantification, the incomplete list, and the interdependence of the risk factors. A biomechanical sorting of the risk factors may shed lights on resolving the above issues. Based on the definition of load-strength ratio (LSR), we first identified the four biomechanical variables determining fracture risk, i.e., the risk of fall, impact force, bone quality, and bone geometry. Then, we explored the links between the FRAX clinical risk factors and the biomechanical variables by looking for evidences in the literature. To accurately assess fracture risk, none of the four biomechanical variables can be ignored and their values must be subject-specific. A clinical risk factor contributes to osteoporotic fracture by affecting one or more of the biomechanical variables. A biomechanical variable represents the integral effect from all the clinical risk factors linked to the variable. The clinical risk factors in FRAX mostly stand for bone quality. The other three biomechanical variables are not adequately represented by the clinical risk factors. From the biomechanical viewpoint, most clinical risk factors are interdependent to each other as they affect the same biomechanical variable(s). As biomechanical variables must be expressed in numbers before their use in calculating LSR, the numerical value of a biomechanical variable can be used as a gauge of the linked clinical risk factors to measure their integral effect on fracture risk, which may be more efficient than to study each individual risk factor.

Osteoporosis: A Silent Disease with Complex Genetic Contribution

Osteoporosis is the most common multifactorial metabolic bone disorder worldwide with a strong genetic component. In this review, the evidence for a genetic contribution to osteoporosis and related phenotypes is summarized alongside with methods used to identify osteoporosis susceptibility genes. The key biological pathways involved in the skeleton and bone development are discussed with a particular focus on master genes clustered in these pathways and their mode of action. Furthermore, the most studied single nucleotide polymorphisms (SNPs) analyzed for their importance as genetic markers of the disease are presented. New data generated by next-generation sequencing in conjunction with extensive meta-analyses should contribute to a better understanding of the genetic basis of osteoporosis and related phenotype variability. These data could be ultimately used for identifying at-risk patients for disease prevention by both controlling environmental factors and providing possible therapeutic targets.

Analysis of osteoporosis treatment patterns with bisphosphonates and outcomes among postmenopausal veterans

PURPOSE

Adherence and persistence with bisphosphonates are frequently poor, and stopping, restarting, or switching bisphosphonates is common. We evaluated bisphosphonate change behaviors (switching, discontinuing, or reinitiating) over time, as well as fractures and costs, among a large, national cohort of postmenopausal veterans.

METHODS

Female veterans aged 50+ treated with bisphosphonates during 2003-2011 were identified in Veterans Health Administration (VHA) datasets. Bisphosphonate change behaviors were characterized using pharmacy refill records. Patients' baseline disease severity was characterized based on age, T-score, and prior fracture. Cox Proportional Hazard analysis was used to evaluate characteristics associated with discontinuation and the relationship between change behaviors and fracture outcomes. Generalized estimating equations were used to evaluate the relationship between change behaviors and cost outcomes.

RESULTS

A total of 35,650 patients met eligibility criteria. Over 6800 patients (19.1%) were non-switchers. The remaining patients were in the change cohort; at least half displayed more than one change behavior over time. A strong, significant predictor of discontinuation was ≥5 healthcare visits in the prior year (11-23% more likely to discontinue), and discontinuation risk decreased with increasing age. No change behaviors were associated with increased fracture risk. Total costs were significantly higher in patients with change behaviors (4.7-19.7% higher). Change-behavior patients mostly had significantly lower osteoporosis-related costs than non-switchers (22%-118% lower).

CONCLUSIONS

Most bisphosphonate patients discontinue treatment at some point, which did not significantly increase the risk of fracture in this majority non-high risk population. Bisphosphonate change behaviors were associated with significantly lower osteoporosis costs, but significantly higher total costs.

The genetics of osteoporosis

INTRODUCTION

Osteoporosis is the commonest metabolic bone disease worldwide. The clinical hallmark of osteoporosis is low trauma fracture, with the most devastating being hip fracture, resulting in significant effects on both morbidity and mortality.

SOURCES OF DATA

Data for this review have been gathered from the published literature and from a range of web resources.

AREAS OF AGREEMENT

Genome-wide association studies in the field of osteoporosis have led to the identification of a number of loci associated with both bone mineral density and fracture risk and further increased our understanding of disease.

AREAS OF CONTROVERSY

The early strategies for mapping osteoporosis disease genes reported only isolated associations, with replication in independent cohorts proving difficult. Neither candidate gene or linkage studies showed association at genome-wide level of significance.

GROWING POINTS

The advent of massive parallel sequencing technologies has proved extremely successful in mapping monogenic diseases and thus leading to the utilization of this new technology in complex disease genetics.

AREAS TIMELY FOR DEVELOPING RESEARCH

The identification of novel genes and pathways will potentially lead to the identification of novel therapeutic options for patients with osteoporosis.

Quantifying Maternal and Paternal Disease History Using Log-Rank Score with an Application to a National Cohort Study

Both maternal and paternal disease history can be important predictors of the risk of common conditions such as heart disease or cancer because of shared environmental and genetic risk factors. Sometimes maternal and paternal history can have remarkably different effects on offspring's status. The results are often affected by how the maternal and paternal disease histories are quantified. We proposed using the log-rank score (LRS) to investigate the separate effect of maternal and paternal history on diseases, which takes parental disease status and the age of their disease onset into account. Through simulation studies, we compared the performance of the maternal and paternal LRS with simple binary indicators under two different mechanisms of unbalanced parental effects. We applied the LRS to a national cohort study to further segregate family risks for heart diseases. We demonstrated using the LRS rather than binary indicators can improve the prediction of disease risks and better discriminate the paternal and maternal histories. In the real study, we found that the risk for stroke is closely related with maternal history but not with paternal history and that maternal and paternal disease history have similar impact on the onset of myocardial infarction.

A sequence variation: 713-8delC in the transforming growth factor beta 1 gene polymorphism in thalassemia major patients

Osteoporosis remains an important cause of morbidity in β-thalassemia major. Although several factors have been implicated to play an important role in the pathogenesis of osteoporosis and several candidate gene polymorphisms have been found to regulate this process, its pathogenesis has not been completely elucidated. Deletion of a C in the fourth intron sequence 8 base before exon 5 (713-8delC) of transforming growth factor beta 1 (TGF-β1) gene which has been reported significantly higher in the osteoporotic group was studied for its prevalence and association with bone mineral density (BMD) in thalassemia major patients. The aim of this study was to find out the distribution of TGF-β1 (713-8delC) sequence variation and its relationship with BMD in thalassemia major patients. 713-8delC Sequence variation polymorphism was detected in 150 β-thalassemia major patients and their BMD was measured by dual-energy X-ray absorptiometry. Biochemical levels were estimated by enzyme-linked immunosorbent assay. We have found a remarkable incidence (90%) of osteopenia and osteoporosis among regularly transfused patients. We have found no association of 713-8delC variant of TGF-β1 gene with Z-score of BMD at lumbar spine (p = 0.061) and hips (p = 0.773). However, Cc genotype of TGF-β1 gene was found as a risk factor (odds ratio: 3.3) for low bone density in these patients.

Primary osteoporosis without features of OI in children and adolescents: clinical and genetic characteristics

Our aim was to characterize clinical findings and familial associations, and to examine candidate genes for disease-causing mutations in a cohort of children suffering from primary osteoporosis without features of osteogenesis imperfecta. Patients with osteoporosis and their nuclear families were studied. Medical history was reviewed. Calcium homeostasis parameters were measured and spinal radiographs obtained. BMD was determined by DXA for patients, parents and siblings. LRP5, LRP6, and PTHLH genes were sequenced. Twenty-seven patients (14 males) from 24 families were recruited. Median age at presentation was 10.1 years (range 3.3-15.6 years). One-third of the children had at least one parent with a BMD below the expected range for age. LRP5, LRP6, and PTHLH showed no causative mutations. Four polymorphisms in LRP5 were overrepresented in patients; the minor allele frequency of Q89R, V667M, N740N, and A1330V was significantly higher than in controls. Age of onset, clinical severity, and inheritance patterns are variable in children with primary osteoporosis. Several patients had evidence suggestive of familial transmission. The underlying genetic factors remain to be elucidated.

The role of the nurse in the management of osteoporosis

Osteoporosis is a chronic disease which is asymptomatic until fractures occur. It is an increasing problem within an ageing population and has many intrinsic and extrinsic risk factors. This article provides an overview of osteoporosis,including the pathogenesis, diagnosis and management.Multidisciplinary assessment and management of osteoporosis is essential with the apt use of non-pharmacologic and pharmacological options to minimize the risk of fracture and appropriately manage patients in an holistic manner.

Bone mass and the CAG and GGN androgen receptor polymorphisms in young men

Background

To determine whether androgen receptor (AR) CAG (polyglutamine) and GGN (polyglycine) polymorphisms influence bone mineral density (BMD), osteocalcin and free serum testosterone concentration in young men.

Methodology/Principal Findings

Whole body, lumbar spine and femoral bone mineral content (BMC) and BMD, Dual X-ray Absorptiometry (DXA), AR repeat polymorphisms (PCR), osteocalcin and free testosterone (ELISA) were determined in 282 healthy men (28.6±7.6 years). Individuals were grouped as CAG short (CAG_S) if harboring repeat lengths of ≤21 or CAG long (CAG_L) if CAG >21, and GGN was considered short (GGN_S) or long (GGN_L) if GGN ≤23 or >23. There was an inverse association between logarithm of CAG and GGN length and Ward's Triangle BMC (r = −0.15 and −0.15, P<0.05, age and height adjusted). No associations between CAG or GGN repeat length and regional BMC or BMD were observed after adjusting for age. Whole body and regional BMC and BMD values were similar in men harboring CAG_S, CAG_L, GGN_S or GGN_L AR repeat polymorphisms. Men harboring the combination CAG_L+GGN_L had 6.3 and 4.4% higher lumbar spine BMC and BMD than men with the haplotype CAG_S+GGN_S (both P<0.05). Femoral neck BMD was 4.8% higher in the CAG_S+GGN_S compared with the CAG_L+GGN_S men (P<0.05). CAG_S, CAG_L, GGN_S, GGN_L men had similar osteocalcin concentration as well as the four CAG-GGN haplotypes studied.

Conclusion

AR polymorphisms have an influence on BMC and BMD in healthy adult humans, which cannot be explained through effects in osteoblastic activity.

Influence of heredity and environment on peak bone density: a parent-offspring study

The aim of the study was to determine the relative influence of heredity and environment on peak bone density and also to estimate the risk of having low peak bone density if the bone density of parents is low. The study comprised 83 families (48 daughters and 35 sons and their parents). The children were at an age when bone density is at its peak at most skeletal sites (22.2+/-1.8 girls; 23.1+/-1.2 boys). Bone mineral density (BMD; g/cm(2)) was determined by dual-energy X-ray absorptiometry. Anthropometric measurements were made, and calcium intake and physical activity were assessed. Heredity accounted for 22-42% of the variation in BMD of the children, depending on the skeletal site. Heritability for cortical BMD of mid-radius was considerably lower than that for spinal trabecular BMD. Children whose parents had low BMDs (T-score< or =-1) were 1.1 times more likely to inherit low BMD. Child BMD depended significantly on parent BMD and also on physical activity. In our study, heredity accounted for the total BMD variation more than the environmental factors. This influence was lower in the cortical than in the trabecular parts of the skeleton. Optimal environmental factors, such as physical activity, may influence the risk of inheriting low BMD.

Strontium ranelate: an effective solution for diverse fracture risks

Osteoporosis is listed by the WHO among the ten most frequent and socio-economically important, chronic diseases of mankind. The term osteoporosis however comprises a number of different pathophysiological conditions and clinical situations of weakened bones with increased risk of fragility fractures. A modern anti-osteoporotic drug should provide qualified study results proving therapeutic efficacy over this broad range of daily clinical appearances of osteoporosis. The decision for treatment in the individual patients depends no longer only on bone mineral density. Today, the major criterion for decision making is the prospective 10-year risk for fractures. Since this risk is calculated on the basis of age, sex, bone mineral density, prevalent fractures, and a number of other contributing risk factors (Kanis et al., Osteoporos Int 12:989-995, 2001; Kanis et al., Osteoporos Int 19:385-397, 2008), it seems to be of interest to have a look whether the fracture-reducing potency of a drug is influenced by these risk factors. The purpose of this review is to analyze whether the fracture-reducing efficacy of strontium ranelate in patients with osteoporosis can be achieved independently of sex, etiology of osteoporosis, and the major diagnostically relevant risk factors.

Bone fractures after menopause

BACKGROUND

Every year 30% of individuals above age 65 fall, and falls are the principal cause of bone fractures. To reduce fracture incidence requires both prevention of falls and maintenance of bone strength.

METHODS

PubMed searches were performed, for studies of the epidemiology of fractures, bone physiology, endocrine effects, osteoporosis measurement, genetics, prevention and effectiveness. Topic summaries were presented to the Workshop Group and omissions or disagreements were resolved by discussion.

RESULTS

Ageing reduces bone strength in post-menopausal women because estrogen deficiency causes accelerated bone resorption. Bone mineral density (BMD) decreased more than 2.5 standard deviation below the mean of healthy young adults defines osteoporosis, a condition associated with an increased risk of fractures. Risk factors such as age and previous fracture are combined with BMD for a more accurate prediction of fracture risk. The most widely used assessment tool is FRAX™ which combines clinical risk factors and femoral neck BMD. General preventive measures include physical exercise to reduce the risk of falling and vitamin D to facilitate calcium absorption. Pharmacological interventions consist mainly in the administration of inhibitors of bone resorption. Randomized controlled trials show treatment improves BMD, and may reduce the relative fracture risk by about 50% for vertebral, 20-25% for non-vertebral and up to 40% for hip fractures although the absolute risk reductions are much lower.

CONCLUSIONS

Although diagnosis of osteoporosis is an important step, the threshold for treatment to prevent fractures depends on additional clinical risk factors. None of the presently available treatment options provide complete fracture prevention.

Hip fracture prevalence in grandfathers is associated with reduced cortical cross-sectional bone area in their young adult grandsons

CONTEXT

Parent hip fracture prevalence is a known risk factor for osteoporosis. The role of hip fracture prevalence in grandparents on areal bone mineral density (aBMD) and bone size in their grandsons remains unknown.

OBJECTIVE

The objective of the study was to examine whether hip fracture prevalence in grandparents was associated with lower aBMD and reduced cortical bone size in their grandsons.

DESIGN AND SETTING

This was a population-based cohort study in Sweden.

STUDY SUBJECTS

Subjects included 1015 grandsons (18.9 +/- 0.6) (mean +/- sd) and 3688 grandparents.

MAIN OUTCOME MEASURES

aBMD, cortical bone size, volumetric bone mineral density and polar strength strain index of the cortex in the grandsons in relation to hip fracture prevalence in their grandparents were measured.

RESULTS

Grandsons of grandparents with hip fracture (n = 269) had lower aBMD at the total body, radius, and lumbar spine, but not at the hip, as well as reduced cortical cross-sectional area at the radius (P < 0.05) than grandsons of grandparents without hip fracture. Subgroup analysis demonstrated that grandsons of grandfathers with hip fracture (n = 99) had substantially lower aBMD at the lumbar spine (4.9%, P < 0.001) and total femur (4.1%, P = 0.003) and lower cortical cross-sectional area of the radius (4.1%, P < 0.001) and tibia (3.3%, P < 0.011). Adjusting bone variables for grandson age, weight, height, smoking, calcium intake, and physical activity and taking grandparent age at register entry, years in register, and grandparent sex into account strengthened or did not affect these associations.

CONCLUSIONS

Family history of a grandfather with hip fracture was associated with reduced aBMD and cortical bone size in 19-yr-old men, indicating that patient history of hip fracture in a grandfather could be of value when evaluating the risk of low bone mass in men.

The use of triiodothyronine as an augmentation agent in treatment-resistant bipolar II and bipolar disorder NOS

BACKGROUND

Thyroid hormone plays a role in both serotonin and catecholamine functions in the brain, and has been linked to abnormal mood states in bipolar disorder. Unlike most studies which have included only patients with bipolar I, this study evaluated triiodothyronine (T3) as an augmentation agent for treatment-resistant depression in patients with bipolar II and bipolar disorder NOS.

METHODS

This study was a retrospective chart review of patients treated in a private clinic between 2002 and 2006. The charts of 125 patients with bipolar II disorder and 34 patients with bipolar disorder NOS were reviewed.

RESULTS

Patients had been unsuccessfully treated with an average of 14 other medications before starting T3. At an average dose of 90.4 mcg (range 13 mcg-188 mcg) the medication was well tolerated. None of the patients experienced a switch into hypomania, and only 16 discontinued due to side effects. Improvement was experienced by 84%, and 33% experienced full remission.

LIMITATIONS

The limitations are those associated with the retrospective chart review design.

CONCLUSIONS

A high percentage of bipolar II and bipolar NOS patients with treatment resistant depression improved on T3. Despite the use of higher than usual doses in many of the patients, the medication was well tolerated. Augmentation with supraphysiologic doses of T3 should be considered in cases of treatment resistant bipolar depression.

Update on the pharmacogenetics of the vitamin D receptor and osteoporosis

Vitamin D and calcium are essential for normal skeletal growth and for maintaining the mechanical and structural integrity of the skeleton. Reduced intake of calcium and vitamin D may be associated with reduced bone mass and osteoporosis while a chronic and severe vitamin D deficiency may lead to osteomalacia. Given the importance of vitamin D in bone homeostasis, common polymorphisms in the vitamin D receptor gene were the first to be investigated as possible determinants of bone mass and fracture risk. Even though results are still conflicting and the molecular mechanisms by which these polymorphisms influence receptor activity remain in part to be investigated, an additional important issue is represented by their potential pharmacogenomic and pharmacogenetic implications. This review analyzes major pharmacogenetic studies of polymorphisms in the vitamin D receptor gene and osteoporosis.

Genetics of bone loss in rheumatoid arthritis--role of vitamin D receptor polymorphisms

RA is a systemic inflammatory arthritis that leads to local and systemic bone loss. Osteoporosis or the systemic bone loss associated with RA increases the risk for fragility fractures, which can affect quality of life dramatically in RA patients. Although traditional and RA-related risk factors have been defined and studied for osteoporosis associated with RA, genetic factors such as polymorphic variants in the traditional candidate genes for osteoporosis, such as the vitamin D receptor (VDR), type 1 collagen A1 (COLIA1) and oestrogen receptor-alpha (ESR1), have not been well elucidated in RA patients. This review summarizes the currently available literature on the association of VDR polymorphisms with local and systemic bone loss in RA. It also discusses potential targets for genetic research in this area, such as polymorphisms in genes, such as IL-6 (IL6) and TNF receptor type 2 (TNFRSF1B), which control the inflammatory response in RA and may influence bone loss in RA. Defining such genetic factors, in addition to traditional and RA-related risk factors for osteoporosis in RA, may facilitate early identification of patients at high risk for fractures who can then be targeted for treatment.

Recent development in pharmacogenomics: from candidate genes to genome-wide association studies

Genetic diversity, most notably through single nucleotide polymorphisms and copy-number variation, together with specific environmental exposures, contributes to both disease susceptibility and drug response variability. It has proved difficult to isolate disease genes that confer susceptibility to complex disorders, and as a consequence, even fewer genetic variants that influence clinical drug responsiveness have been uncovered. As such, the candidate gene approach has largely failed to deliver and, although the family-based linkage approach has certain theoretical advantages in dealing with common/complex disorders, progress has been slower than was hoped. More recently, genome-wide association studies have gained increasing popularity, as they enable scientists to robustly associate specific variants with the predisposition for complex disease, such as age-related macular degeneration, Type 2 diabetes, inflammatory bowel disease, obesity, autism and leukemia. This relatively new methodology has stirred new hope for the mapping of genes that regulate drug response related to these conditions. Collectively, these studies support the notion that modern high-throughput single nucleotide polymorphism genotyping technologies, when applied to large and comprehensively phenotyped patient cohorts, will readily reveal the most clinically relevant disease-modifying and drug response genes. This review addresses both recent advances in the genotyping field and highlights from genome-wide association studies, which have conclusively uncovered variants that underlie disease susceptibility and/or variability in drug response in common disorders.

Long-term effects of progestins on bone quality and fractures

The effects of progestins on the quality of bone and their influence on the risk of fractures are reviewed. Data discussed are based on experimental studies in vivo that generally lasted for longer than one year. Information is given on the background of osteoporosis and on several means of inducing changes in bone quality. In young women who start using oral contraceptives based on progestins alone shortly after pubertal development, a significant decrease in bone quality has been documented. World Health Organization experts have concluded that this is not a real argument for restrictions on the use of these contraceptives. In postmenopausal women, no evidence has been found for a bone-protective or an estrogen-antagonistic effect of progestins. A wide range of estrogens have been used that have shown positive effects on bone, which are not antagonized by progestins. The therapeutic use of high-dose megestrol acetate may result in marked negative effects on bone, leading to severe osteoporosis, possibly due to the inherent glucocorticoid activity of this progestin. Other pharmacotherapeutic agents that can be used in postmenopausal therapy, and that clearly have beneficial effects on bone, are discussed.

Osteoporosis in men

Osteoporosis has long been considered to be a disease of the aging female skeleton. As awareness of the pervasiveness of this disorder increases, it is clear that men are also at risk for this disorder. Recent epidemiological studies have confirmed that osteoporosis in men is an increasing health problem. This development not only has its roots in increased longevity but also in increased awareness of this problem in men. The purpose of this article is to review what is known about the factors in men that lead to acquisition, maintenance, and loss of bone, as well as new insights about the causes, pathogenesis, and treatment of osteoporosis in men.

Familial aggregation of forearm bone mineral density in Chinese

Osteoporosis is a major public health concern and its prevalence can be predicted based on forearm bone mineral density (BMD). This study is to investigate the familial aggregation of forearm BMD in a population-based, cross-sectional study in Anhui, China. Information on sociodemographic and environmental variables was obtained from 1,636 subjects from 409 nuclear families (including mother, father, and their first two children) by a standardized questionnaire. The forearm BMD was measured by peripheral dual-energy X-ray absorptiometry (pDXA). Using generalized additive models with a sequential adjustment for covariates, it was clearly indicated that the forearm BMD of the mother, the father, and the first sibling each had a significant and independent relation to the forearm BMD of the second sibling. Furthermore, using multiple logistic regression, the second sibling had an odds ratio (OR) of 5.3 (95%CI: 2.0-14.5) of having an extremely low (bottom 10th percentile) proximal forearm BMD and an OR of 4.3 (95%CI: 1.6-12.0) of having an extremely low distal forearm BMD when the parental mean forearm BMD was low and the first sibling's forearm BMD was low. Our findings showing strong familial aggregation of both proximal and distal forearm BMD values suggest that genetic factors play a significant role in determining both traits.

Genetics and osteoporosis

Over the past 10 years, many advances have been made in understanding the mechanisms by which genetic factors regulate susceptibility to osteoporosis. It has become clear from studies in man and experimental animals that different genes regulate BMD at different skeletal sites and in men and women. Linkage studies have identified several chromosomal regions that regulate BMD, but only a few causative genes have been discovered so far using this approach. In contrast, significant advances have been made in identifying the genes that cause monogenic bone diseases, and polymorphic variation is some of these genes has been found to contribute to the genetic regulation of BMD in the normal population. Other genes that have been investigated as possible candidates for susceptibility to osteoporosis because of their role in bone biology, such as vitamin D, have yielded mixed results. Many candidate gene association studies have been underpowered, and meta-analysis has been used to try to confirm or refute potential associations and gain a better estimate of their true effect size in the population. Most of the genetic variants that confer susceptibility to osteoporosis remain to be discovered. It is likely that new techniques such as whole-genome association will provide new insights into the genetic determinants of osteoporosis and will help to identify genes of modest effect size. From a clinical standpoint, genetic variants that are found to predispose to osteoporosis will advance our understanding of the pathophysiology of the disease. They could be developed as diagnostic genetic tests or form molecular targets for design of new drugs for the prevention and treatment of osteoporosis and other bone diseases.

The A1330V polymorphism of the low-density lipoprotein receptor-related protein 5 gene (LRP5) associates with low peak bone mass in young healthy men

INTRODUCTION

Polymorphisms in the gene coding for low-density lipoprotein receptor-related protein 5 (LRP5) contribute to variation in bone mass in the general population. Whether this is due to influence on bone mass acquisition or on bone loss thereafter has not been established.

METHODS

We studied the association of LRP5 polymorphisms with peak bone mass in young men. The study included 235 Finnish men, aged 18.3 to 20.6 years. Lifestyle factors and fracture history were recorded. Bone mineral content (BMC), density (BMD) and scan area were measured for the lumbar spine and proximal femur by dual energy X-ray absorptiometry (DXA). Blood and urine were collected for determination of bone turnover markers, serum 25-OHD and PTH. Genomic DNA was extracted from peripheral blood for genetic analysis of LRP5. Ten single nucleotide polymorphisms in LRP5 were analyzed and correlated with bone parameters.

RESULTS

Only the A1330V polymorphism of LRP5 significantly associated with bone parameters. In comparison with subjects with the AlaAla genotype (n=215), those with AlaVal genotype (n=20) had lower femoral neck BMC (P=0.029) and BMD (P=0.012), trochanter BMC (P=0.0067) and BMD (P=0.015), and total hip BMC (P=0.0044) and BMD (P=0.0089). Fracture history was similar for the genotypes.

CONCLUSION

The polymorphic valine variant at position 1330 of LRP5 was significantly associated with reduced BMC and BMD values in healthy young Finnish men. The results provide evidence for the crucial role of LRP5 in peak bone mass acquisition.

Gene polymorphisms involved in the regulation of bone quality

Osteoporotic fractures in subjects at advanced age constitute a tremendous and growing problem. Established lifestyle risk factors can explain only a modest proportion of the liability to osteoporotic fractures. Bone mineral density (BMD) is considered the best established risk factor for osteoporotic fractures. The importance of genetic factors in the quality of bone is substantial, but no consensus exists yet on the genes that are involved. However, concomitant diseases, balance disorders and lifestyle habits are more important for fractures in elderly subjects. The abundance of common sequence variations, so-called polymorphisms, in the human genome and their high frequency in the population have made them targets to explain variation in the risk. Some genes have been identified that appear to be involved in the regulation of bone mass and in the pathogenesis of osteoporosis. Among these are those coding for the two estrogen receptors (ERalpha and ERbeta), the androgen receptor (AR) and the vitamin D receptor (VDR). In addition, enzymes involved in the biogenesis of estrone and estradiol have attracted attention as well as polymorphisms in the regulatory region of the type I collagen gene, COLIA1, affecting the binding site for the transcription factor Specificity protein 1 (Sp1). Although evidence suggests that the quality of bone is determined to a large extent by genetic factors, research so far has not been able to unequivocally identify genes involved in this matter. Over the last years a large number of studies have pointed to the variability in many genes and their relation with BMD, bone-related symptoms or specific therapies. The findings emphasize the complexity of the genetics of bone mass and bone loss.

Osteoporosis in otherwise healthy perimenopausal and early postmenopausal women: physical and biochemical characteristics

Population studies have shown that about 3-5% of perimenopausal women already have osteoporosis according to the WHO definition of osteoporosis for postmenopausal women ( t -score<or=-2.5). In general, this bone loss arises from well-characterized diseases or conditions that affect acquisition of peak bone mass and/or the rate of bone loss after peak bone mass has been attained. However, there often remains a subset of these women, with no identifiable cause of bone loss. This group has so far been little studied. We prospectively evaluated a group of 60 perimenopausal and early postmenopausal women (mean age 52.2+/-2.5 years) who were found to have apparently unexplained low bone mass, and we compared them to 120 controls matched for age and menopausal status. These women were extensively investigated, including by detailed questionnaire and laboratory testing. Of the 60 women with osteoporosis, only three were found to have previously undiagnosed disorders (two with subclinical hyperthyroidism and one with elevated serum PTH levels) that might have contributed to their low bone mass. On the other hand, osteoporotic patients were characterized by a significantly lower body weight, higher prevalence of personal and parental histories of fractures and a higher level of bone turnover as assessed by increased serum osteocalcin and bone alkaline phosphatase levels and urinary type I collagen C-telopeptide (CTX) excretion, as compared to controls. These findings support theories of a genetic contribution to osteoporosis and underline the predictive value of a previous history of personal and familial fracture in the identification of osteoporosis in early postmenopausal women.

MTHFR c.677C>T polymorphism as an independent predictor of peak bone mass in Danish men--results from the Odense Androgen Study

The MTHFR c.677C>T polymorphism has been shown to have significant effects on skeletal health in middle-aged to elderly women and men. Despite an accumulating amount of data on MTHFR genetics and the association between homocysteine levels and fracture, it remains unknown if MTHFR c.677C>T genotype affects bone mineral accretion in youth or bone loss in adulthood. The purpose of this cross-sectional study was to examine the effects of this common allelic polymorphism on peak bone mass and bone turnover. We performed MTHFR genotyping in 780 healthy Danish men, aged 20 to 29 years, participating in the Odense Androgen Study. BMD at the spine, hip and whole-body was measured using a Hologic QDR-4500 densitometer. Genotype frequencies were compatible with Hardy-Weinberg equilibrium. Spine BMD was significantly associated with genotype, with a decrease in BMD of 0.20 SD for each copy of the T-allele. Effects were independent of age, BMI, smoking and serum levels of vitamin D and IGF-I. Associations with BMD of the hip and whole body were short of statistical significance. MTHFR genotype showed no association with the bone turnover markers 1-CTP, bone specific alkaline phosphatase or osteocalcin. In conclusion, significant skeletal effects of this common polymorphism were present at the lumbar spine in men at the age of 25 years.

Lean mass plays a gender-specific role in familial resemblance for femoral neck bone mineral density in adult subjects

Whether the femoral neck bone mineral density (FN BMD) of children may be better predicted from that of their parents when taking into account the anthropometry of the children was assessed in a healthy adult sample consisting of 86 mother-daughter, 32 mother-son, 32 father-daughter, and 23 father-son pairs from 128 families. Heritability for FN BMD, which is considered to be a measurement of general resemblance, was defined as the regression coefficient of the mean of the parents' BMD. Among the anthropometric factors, lean mass was the most strongly associated with FN BMD following the adjustment for age in women (r=0.52, p<0.0001) and men (r=0.25, p=0.02). After adjustment for age, calcium intake, physical activity, and menopause and hormonal replacement therapy if relevant, heritability estimates (h2) for FN BMD were 0.68+/-0.23 [95% credible interval (CI): 0.15-0.99] in father-daughter pairs, 0.40+/-0.17 (95% CI: 0.08-0.74) in mother-daughter pairs, and 0.19+/-0.15 (95% CI: 0.01-0.57) in father-son pairs. Adjustment for lean mass of children increased the h2 for FN BMD in mother-son pairs [from 0.24+/-0.17 (95% CI: 0.01-0.57) to 0.66+/-0.18 (95% CI: 0.26-0.95)]. The present results show that FN BMD is heritable in adult father-daughter pairs (7.2% of a daughter's FN BMD variance was explained by the father's FN BMD) and that taking into account the lean mass of sons might improve the prediction of their FN BMD based on that of their mother's (reduction of sons' FN BMD residual variance by 5.1%). Taking the lean mass of children into account might improve the prediction of their FN BMD by 9.1% in daughters and by 18.1% in sons, irrespective of their parent's FN BMD. These results, obtained using a Bayesian regression model, have to be confirmed in further studies involving a greater number of adult parent-offspring pairs of both genders before extrapolation to clinical practice.

Factors associated with the lumbar spine and proximal femur bone mineral density in older men

Bone mass is a major determinant of fracture, but there have been few comprehensive studies of the correlates of bone mineral density (BMD) in older men. The objective of the current cross-sectional analysis was to determine the factors associated with BMD of the lumbar spine and proximal femur in a large population-based sample of older men enrolled in The Osteoporotic Fractures in Men Study, "Mr.OS." We enrolled 5,995 men 65 years of age or older, 89% Caucasian, in Mr.OS at six US clinical centers. Demographic, medical and family history and lifestyle information was obtained by interview and physical function and anthropometric data by examination. Spine and hip BMD was measured using dual-energy X-ray absorptimetry. The multivariable linear regression models predicted 19 and 10% of the overall variance in BMD of the femoral neck and spine, respectively. African-American men had 6 to 11% higher BMD than Caucasian men independent of multiple factors. Hip BMD declined with advancing age, while spine BMD increased. Body weight (per 10 kg) and self report of diabetes were each associated with 2 to 4% higher BMD, while history of a non-trauma fracture and current use of selective serotonin reuptake inhibitors, but not other antidepressants, were associated with at least 4% lower BMD. Both maternal and paternal histories of fracture were associated with 1.4-1.7% lower BMD. Osteoarthritis, physical activity, grip strength, alcohol intake, and dietary calcium were positively related to BMD, while a history of chronic lung disease, prostate cancer, and kidney stones was associated with lower BMD. Smoking, caffeine intake, and thiazide diuretics were not related to BMD in older men. A number of lifestyle and behavioral characteristics and medical conditions were associated with BMD in older men. Identification of these correlates could improve methods to identify men at risk for fracture and improve our understanding of fracture etiology.