Bone mineral density, carotid artery intimal medial thickness, and the vitamin D receptor BsmI polymorphism in Mexican American women

The relationship of bone mineral density with the of the intima-media thickness in premenopausal women

Background: Osteoporosis and cardiovascular disease (CVD) are among the most common causes of morbidity, disability and death worldwide. In recent years, more and more data have been accumulating on the presence of an age-independent relationship and general pathogenetic mechanisms of a decrease in bone mineral density (BMD) and the development of CVD. It has been shown that a decrease in BMD is an important independent predictor of the risk of atherosclerosis of the great arteries and is associated with increased calcification of the aorta and other vessels. The strongest relationship between these parameters was observed in the study of the female population, in connection with which we selected a group of middle-aged women for analysis.

Objective: to investigate the association between bone mineral density and carotid intima-media thickness in middle-aged women.

Results: 35 women were included in the study. The mean age was 44,74±4,32 years. We found the following changes in arterial wall characteristics: atherosclerosis — 21,9% women, increased carotid intima thickness — 15,7% women. Low bone mineral density for chronological age (Z-criteria -2,0 and less) was found in 7 patients at the age of 35±2,7 years. We discovered a negative correlation between the markers of subclinical atherosclerosis and bone mass: Ccarotid intimamedia thickness negatively correlated with bone mineral density in hip (p<0,05), and presence of atherosclerosis plaques was associated with lower bone mineral density in the proximal part of hip (p<0,05).

Conclusion: The findings about negative association between bone mineral density of hip with preclinical markers of atherosclerosis allow us to make a conclusion about their interaction.

Association between carotid intima-media thickness and bone mineral density: a cross-sectional study in Vietnamese men and women aged 50 years and older

OBJECTIVES

The association between osteoporosis and atherosclerosis remains controversial. We sought to define the relationship between carotid intima-media thickness and bone mineral density (BMD) in individuals of Vietnamese background.

DESIGN AND SETTING

Cross-sectional study in Ho Chi Minh City, Vietnam.

PARTICIPANTS

The study involved 1460 individuals (559 men) aged 50 years and older (average age 59 years) who were randomly recruited from the community.

OUTCOME MEASURES

BMD at the femoral neck and lumbar spine was measured by dual-energy X-ray absorptiometry (Hologic, Waltham, Massachusetts, USA). Carotid intima-media thickness (cIMT) was measured using a Philips Ultrasonography (HD7XE). The presence of atherosclerotic plaque was ascertained for each individual. The association between cIMT and BMD was analysed by a multiple linear regression model.

RESULTS

In unadjusted analysis, cIMT was positively associated with femoral neck BMD in men (p=0.005), but not in women (p=0.242). After adjusting for age, smoking, diabetes and hypertension, the association remained statistically significant in men (partial R²=0.005; p=0.015) but not in women (partial R²=0.008; p=0.369). When the analysis was limited to individuals aged 60 years and older, the association between cIMT and BMD was no longer statistically significant. There was no statistically significant association between cIMT and lumbar spine BMD in either men or women.

CONCLUSIONS

In Vietnamese individuals aged 50 years and older, there is a clinically non-significant but statistically significant association between carotid intima-media thickness and BMD in men, not in women.

Role of Vitamin D in Intima Media Thickness in Patients with Type 1 Diabetes Mellitus

Increased carotid intima media thickness indicates subclinical atherosclerosis. We evaluated the relation between vitamin D level and intima media thickness in patients with type 1 DM. 93 patients (female/male: 48/45, aged 31.5 ± 11.9 years, A1c 9.48 ± 2.43, vitamin D [15.9 (12.1-19.2)]) with type 1 DM were included into the study. Common carotid artery IMT was measured by real time B mode ultrasonography (MyLab 70 XVG, Esaote SpA, Genoa, Italy). Vitamin D was measured using radioimmunassay. Male and female patients (n = 14, 15%) had similar rates of plaque presence (p = 0.377). IMT was similar according to gender. IMT [0.45 (0.40-0.50)] was positively correlated with age, duration of diabetes, creatinine, LDL/HDL ratio, and ALP. Median IMT was higher in current smokers, patients with retinopathy, and nephropathy, and overweight/obese patients. IMT was not different according to vitamin D status. However calcium level corrected for albumin was in positive correlation with mean IMT (r = 0.221, p = 0.033). We detected high frequency of vitamin D deficiency (78%) defined as less than 20 ng/ml. Vitamin D and diabetes control defined as A1c have no effect on intima media thickness in type 1 DM. Traditional cardiovascular risk factors including age, duration of DM, smoking, and BMI adversely affect intima media thickness.

Association between Lumbar Bone Mineral Density and Carotid Intima-Media Thickness in Korean Adults: a Cross-sectional Study of Healthy Twin Study

Bone mineral density (BMD) has been suggested to be associated with atherosclerosis. In the present study, we evaluated the association between lumbar BMD and the segments of carotid intima-media thickness (CIMT), a surrogate marker of subclinical atherosclerosis, in Korean adults, with consideration of sex and menopause status. Among 1,679 Korean adults who enrolled in a Healthy Twin Study, 723 men, 690 premenopausal women, and 266 postmenopausal women measured the CIMT at the common carotid artery intima-media thickness (CCA-IMT), carotid bifurcation intima-media thickness (BIF-IMT), internal carotid artery intima-media thickness (ICA-IMT) using B-mode ultrasound and lumbar BMD using dual-energy X-ray absorptiometry. The composite CIMT was calculated as the mean value of three CIMTs. The association was evaluated using linear mixed models. In premenopausal women, lumbar BMD was positively associated with composite CIMT and with CCA-IMT (P = 0.008 and 0.002, respectively). However, no association was observed between BMD and CIMT in men or in postmenopausal women. Stratified analysis revealed the effect of body mass index (BMI) on the association between BMD and CIME. The positive association in premenopausal women persisted only in low BMI (< 25 kg/m²) group, whereas a positive association appeared at high BMI (≥ 25 kg/m²) group in men. A high lumbar BMD may indicate an elevated risk of subclinical atherosclerosis in premenopausal women and men with high BMI.

Interplay of vitamin D, erythropoiesis, and the renin-angiotensin system

For many years deficiency of vitamin D was merely identified and assimilated to the presence of bone rickets. It is now clear that suboptimal vitamin D status may be correlated with several disorders and that the expression of 1-α-hydroxylase in tissues other than the kidney is widespread and of clinical relevance. Recently, evidence has been collected to suggest that, beyond the traditional involvement in mineral metabolism, vitamin D may interact with other kidney hormones such as renin and erythropoietin. This interaction would be responsible for some of the systemic and renal effects evoked for the therapy with vitamin D. The administration of analogues of vitamin D has been associated with an improvement of anaemia and reduction in ESA requirements. Moreover, vitamin D deficiency could contribute to an inappropriately activated or unsuppressed RAS, as a mechanism for progression of CKD and/or cardiovascular disease. Experimental data on the anti-RAS and anti-inflammatory effects treatment with active vitamin D analogues suggest a therapeutic option particularly in proteinuric CKD patients. This option should be considered for those subjects that are intolerant to anti-RAS agents or, as add-on therapy, in those already treated with anti-RAS but not reaching the safe threshold level of proteinuria.

Vertebral fractures on routine chest computed tomography: relation with arterial calcifications and future cardiovascular events

Osteoporosis and cardiovascular disease often coexist. Vertebral fractures incidentally imaged in the course of routine care might be able to contribute to the prediction of cardiovascular events. Following a case-cohort design, 5,679 patients undergoing chest CT were followed for a median duration of 4.4 years. Cases were defined as patients who subsequently developed a cardiovascular event (n = 493). The presence and severity of vertebral fractures, as well as aortic, coronary and valvular calcifications on CT were investigated. Cases were more likely to be male (69 vs 60 %) and older (66 vs 61 years old). Prevalent vertebral fractures conferred an elevated risk of cardiovascular events after adjustment for age and gender [hazard ratio (HR) of 1.28, 95 % confidence interval (CI) 1.07 to 1.54]. This effect remained moderate after correction for cardiovascular calcifications (HR 1.20, CI 0.99-1.44). However, in terms of discrimination, vertebral fractures did not have substantial incremental prognostic value after correction (C-index was 0.683 vs 0.682 for models with and without vertebral fractures respectively). Prevalent vertebral fractures on routine clinical chest CT are related to future cardiovascular events but do not have additional prognostic value to models that already include age, gender and cardiovascular calcifications.

Association between vitamin D receptor gene polymorphisms (Fok1 and Bsm1) and osteoporosis: a systematic review

Osteoporosis is a health concern characterized by reduced bone mineral density (BMD) and increased risk of fragility fractures. Many studies have investigated the association between genetic variants and osteoporosis. Polymorphism and allelic variations in the vitamin D receptor gene (VDR) have been found to be associated with bone mineral density. However, many studies have not been able to find this association. Literature review was conducted in several databases, including MEDLINE/Pubmed, Scopus, EMBASE, Ebsco, Science Citation Index Expanded, Ovid, Google Scholar, Iran Medex, Magiran and Scientific Information Database (SID) for papers published between 2000 and 2013 describing the association between Fok1 and Bsm1 polymorphisms of the VDR gene and osteoporosis risk. The majority of the revealed papers were conducted on postmenopausal women. Also, more than 50% studies reported significant relation between Fok1, Bsm1 and osteoporosis. Larger and more rigorous analytical studies with consideration of gene-gene and gene-environment interactions are needed to further dissect the mechanisms by which VDR polymorphisms influence osteoporosis.

Vitamin D, folate, and potential early lifecycle environmental origin of significant adult phenotypes

Solar radiation early in pregnancy interacts with light sensitive vitamins to influence an embryo's genetic profile. This influences both adult disease risk and may play a role in the evolution of skin colour.

Background and objectives: Vitamin D and folate are highly UV sensitive, and critical for maintaining health throughout the lifecycle. This study examines whether solar irradiance during the first trimester of pregnancy influences vitamin D receptor (VDR) and nuclear folate gene variant occurrence, and whether affected genes influence late-life biochemical/clinical phenotypes.

Methodology: 228 subjects were examined for periconceptional exposure to solar irradiance, variation in vitamin D/folate genes (polymerase chain reaction (PCR)), dietary intake (food frequency questionnaire (FFQ)) and important adult biochemical/clinical phenotypes.

Results: Periconceptional solar irradiance was associated with VDR-BsmI (P = 0.0008^wk7), TaqI (P = 0.0014^wk7) and EcoRV (P = 0.0030^wk6) variant occurrence between post-conceptional weeks 6–8, a period when ossification begins. Similar effects were detected for other VDR gene polymorphisms. Periconceptional solar irradiance was also associated with 19 bp del-DHFR (P = 0.0025^wk6), and to a lesser extent C1420T-SHMT (P = 0.0249^wk6), a folate-critical time during embryogenesis. These same genes were associated with several late-life phenotypes: VDR-BsmI, TaqI and ApaI determined the relationship between dietary vitamin D and both insulin (P < 0.0001/BB, 0.0007/tt and 0.0173/AA, respectively) and systolic blood pressure (P = 0.0290/Bb, 0.0299/Tt and 0.0412/AA, respectively), making them important early and late in the lifecycle. While these and other phenotype associations were found for the VDR variants, folate polymorphism associations in later-life were limited to C1420T-SHMT (P = 0.0037 and 0.0297 for fasting blood glucose and HbA1c levels, respectively). We additionally report nutrient–gene relationships with body mass index, thiol/folate metabolome, cognition, depression and hypertension. Furthermore, photoperiod at conception influenced occurrence of VDR-Tru9I and 2R3R-TS genotypes (P = 0.0120 and 0.0360, respectively).

Conclusions and implications: Findings identify environmental and nutritional agents that may interact to modify gene–phenotype relationships across the lifecycle, offering new insight into human ecology. This includes factors related to both disease aetiology and the evolution of skin pigmentation.

Effects of vitamin d on blood pressure and endothelial function

Vitamin D deficiency is prevalent, primarily due to limited sun exposure, which may be observed in urban areas, or as a result of modern lifestyles. Common myths about vitamin D persist, including that it is mostly obtained from the diet and is only essential for bone and mineral homeostasis. Nonetheless, advances in biomedical science suggest that vitamin D is a hormone that is integral to numerous physiologic functions in most cells and tissues. Therefore, abnormal vitamin D levels may contribute to health disturbances. A number of recent reports on potential associations between vitamin D deficiency and cardiovascular disease have highlighted its role in this system. A focus over the previous decade has been to better understand the mechanisms behind vitamin D regulation and the pathophysiology associated with suboptimal vitamin D levels. Vitamin D deficiency is highly associated with the incidence of cardiovascular diseases, even when considering other well-known risk factors. In this process, the renin-angiotensin system is disrupted, and hypertension and endothelial dysfunction contribute to the risk of cardiovascular disease. Likewise, clinical outcomes upon the normalization of vitamin D levels have been investigated in different patient populations. It makes sense that vitamin D supplementation to improve vitamin D status among vitamin D-deficient individuals could be useful without requiring a sudden lifestyle change. This manuscript provides a brief overview of vitamin D metabolism and the vitamin D receptor. It also summarizes the current clinical research relating to vitamin D supplementation and its effects on hypertension and endothelial dysfunction in cardiovascular medicine.

Evidence for a genetic link between bone and vascular measures in African ancestry families

Bone mineral density (BMD) has been inversely associated with subclinical and clinical cardiovascular disease (CVD) in population studies, but the potential mechanisms underlying this relationship are unclear. To test if there is a genetic basis underlying this association, we determined the phenotypic and genetic correlations between BMD and carotid artery ultrasound measures in families. Dual-energy X-ray absorptiometry and peripheral quantitative computed tomography were used to measure BMD in 461 individuals with African ancestry belonging to seven large, multigenerational families (mean family size 66; 3414 total relative pairs). Carotid artery ultrasound was used to measure adventitial diameter (AD) and intima-media thickness (IMT). Phenotypic and genetic correlations between BMD and carotid measures were determined using pedigree-based maximum likelihood methods. We adjusted for potential confounding factors, including age, sex, body weight, height, menopausal status, smoking, alcohol intake, walking for exercise, diabetes, hypertension, serum lipid and lipoprotein levels, inflammation markers, and kidney function. We found statistically significant phenotypic (ρ = -0.19) and genetic (ρG  = -0.70) correlations (p < 0.05 for both) between lumbar spine BMD and AD in fully adjusted models. There was also a significant genetic correlation between trabecular BMD at the radius and IMT in fully adjusted models (ρG  = -0.398; p < 0.05). Our findings indicate that the previously observed association between osteoporosis and CVD in population-based studies may be partly mediated by genetic factors and that the pleiotropic effects of these genes may operate independently of traditional risk pathways.

Low Bone Mass is Associated with Increased Carotid Intima Media Thickness in Men with Type 2 Diabetes Mellitus

Osteoporosis and atherosclerosis share common risk factors and the association of low bone mass with increased cardiovascular morbidity and mortality has been demonstrated in some studies. Nevertheless, most studies have been focused on women and only a few on individuals with type 2 diabetes mellitus (T2DM). The measurement of carotid intimal-medial thickness (CIMT) is able to detect early atherosclerotic changes and is a predictive marker of cardiovascular events. The aim of this study was to assess the CIMT and its relationship with bone mineral density (BMD) (in the femoral neck (FN) and lumbar spine (LS)) in men with T2DM. We conducted a cross-sectional study with 24 men with T2DM (aged 61 ± 6.4 years) and evaluated metabolic factors, bone densitometry values, and CIMT measured using B-mode Logic-E ultrasound machine. More than 5 years since the diagnosis of T2DM had passed in 75% of the patients, 41.6% were in statin use, mean body mass index (BMI) was 28.1 ± 3.4 kg/m², abdominal circumference (AC) 97.8 ± 8.4 cm, systolic blood pressure (SBP) 143.8 ± 18.3 mmHg, diastolic blood pressure (DBP) 85.8 ± 12.3 mmHg, HbA_1C 7.5% ± 1.3%, Triglycerides 141.7 ± 73 mg/dL, LDL-cholesterol 103.3 ± 35.9 mg/dL, HDL-cholesterol 41.6 ± 11.6 mg/dL. The patients were stratified into groups according to BMD. The group with normal BMD at FN had mean CIMT of 0.7 mm and the group with low bone mass (osteopenia or osteoporosis) had CIMT of 0.86 mm (P = 0.007). In addition, there were no significant differences between groups regarding age, duration of T2DM, BMI, AC, SBP, DBP, statin use, smoking, HbA_1C, cholesterol, or triglycerides. Our data demonstrate a negative association between BMD at the FN and CIMT in type 2 diabetic men, which was unrelated to the traditional risk factors for atherosclerotic disease and degree of diabetes control.

Aortic calcification and bone metabolism: the relationship between aortic calcification, BMD, vertebral fracture, 25-hydroxyvitamin D, and osteocalcin

The aim of this study was to investigate the relationship between aortic calcification (AC) and low bone mineral density (BMD), 25(OH)D, C-terminal telopeptide (CTx), and osteocalcin levels in Asian women. We also tried to find the association between AC and the risk of vertebral fracture. We included 769 patients in this study. All patients underwent QCT. Aortic calcium score (ACS) was quantified by the Agatston scoring method. Spinal fracture was defined by lumbar spine radiography. Among 769 subjects, 96 had at least one vertebral fracture and 345 had AC. ACS positively correlated with age. Osteocalcin, CTx, 25(OH)D, total-hip trabecular BMD (tBMD), femoral neck tBMD, and vertebral tBMD were inversely related with ACS. However, cortical BMD (cBMD) did not correlate with ACS. Among these parameters, only osteocalcin significantly correlated with ACS, even after adjusting for age. We divided the subjects into two groups based on the presence of AC to determine the association between AC and vertebral fracture. Multivariate logistic regression analysis showed that age, tBMD of each site, and AC were associated with vertebral fractures. After adjusting for confounding factors, patients with AC had more than a threefold increased risk of vertebral fracture (OR = 3.29-3.57, P < 0.05 according to site). This study suggests that high ACS is related to low tBMD but not cBMD. Furthermore, our findings indicate that this relationship is definitely age-dependent. Finally, we found that AC is significantly associated with the prevalence of vertebral fracture in Asian women.

Bone Mineral Density as a Predictor of Atherosclerosis and Arterial Wall Stiffness in Obese African-American Women

Bone demineralization is associated with higher cardiovascular event rates, possibly due to vascular calcification and accelerated atherosclerosis. African-Americans have less bone loss and less calcium content within atherosclerotic plaques. However, whether loss of bone mass is related to atherosclerosis has not been examined in African-Americans. The objective of this study was to evaluate possible associations between bone mineral density (BMD), carotid intimal-medial thickness (CIMT), and arterial stiffness. We studied 100 obese African-American women (BMI: 26.6 ± 6.2; age: 63 ± 14 years) referred for BMD estimation by dual-energy X-ray absorptiometry scan. BMD (g/cm(2)) was obtained at the lumbar spine (L1-L4), femoral neck, and total hip. Arterial stiffness was evaluated by the heart rate-corrected augmentation index (AI@75) and pulse wave velocity (PWV) using applanation tonometry. CIMT was measured by vascular ultrasound. Mean CIMT, AI@75, and PWV were 0.72 ± 0.14 mm, 28.8 ± 9.0%, and 8.9 ± 1.6 m/s, respectively. Mean BMD values at the lumbar spine, femoral neck, and hip were 0.96 ± 0.19, 0.80 ± 0.16, and 0.91 ± 0.17 g/cm(2). Older subjects had higher CIMT (r = 0.61, p < 0.001) and AI@75 (r = 0.42, p < 0.001). There was a significant correlation between AI@75 and CIMT (r = 0.45, p < 0.001). BMD was negatively correlated with AI@75 (lumbar: r = -0.22, p = 0.03; femoral neck: r = -0.24, p = 0.01; hip: r = -0.21, p = 0.03). BMD was unrelated to CIMT (lumbar: r = -0.09, p = 0.42; femoral neck: r = -0.15, p = 0.17; hip: r = -0.13, p = 0.23). On multivariate analysis, age (p < 0.001), hypertension (p = 0.02), and lumbar BMD (p = 0.01, R(2) = 0.30) were independent predictors of increased AI@75 after adjusting for age, height, and cardiovascular risk factors. These findings were unchanged upon substitution of femoral neck BMD (p = 0.05, R(2) = 0.28) into the model. There was a trend with hip BMD (p = 0.06, R(2) = 0.28) in the regression model. Age-matched comparison between normal BMD (n = 25) and osteoporotic patients (n = 34) demonstrated a significant difference in AI@75 (26.6 ± 8.9 vs. 31.6 ± 9.1%, p = 0.04). In summary, women with lower BMD had increased arterial stiffness. There was no relationship between BMD and atherosclerosis. In conclusion, age, hypertension, and BMD are independent predictors of higher arterial stiffness. Vascular changes are related to bone mineral loss, suggesting lower BMD may increase cardiovascular risk in African-Americans.

ROL' tsITOKINOV V RAZVITII SERDEChNO-SOSUDISTyKh ZABOLEVANIY I OSTEOPOROZA

At thepresent time there is a great interest in médical researche devoted to investigation the role of cytokines (interleukins) in the pathogenesis of cardiovascular diseases (atherosclerosis, arterial hypertension, ischemic heart disease, etc.), and osteoporosis. The review provides data on the conducted research on the importance of cytokines in the event of these diseases.

Arterial stiffening relates to arterial calcification but not to noncalcified atheroma in women. A twin study

OBJECTIVES

Our aim was to examine the relationship of arterial stiffness to measures of atherosclerosis, arterial calcification, and bone mineral density (BMD); the heritability of these measures; and the degree to which they are explained by common genetic influences.

BACKGROUND

Arterial stiffening relates to arterial calcification, but this association could result from coexistent atherosclerosis. A reciprocal relationship between arterial stiffening/calcification and BMD could explain the association between cardiovascular morbidity and osteoporosis.

METHODS

We examined, in 900 women from the Twins UK cohort, the relationship of carotid-femoral pulse wave velocity (cfPWV) to measures of atherosclerosis (carotid intima-media thickening; carotid/femoral plaque), calcification (calcified plaque [CP]; aortic calcification by computed tomography, performed in subsample of 40 age-matched women with low and high cfPWV), and BMD.

RESULTS

The cfPWV independently correlated with CP but not with intima-media thickness or noncalcified plaque. Total aortic calcium, determined by computed tomography, was significantly greater in subjects with high cfPWV (median Agatston score 450.4 compared with 63.2 arbitrary units in subjects with low cfPWV, p = 0.001). There was no independent association between cfPWV and BMD. Adjusted heritability estimates of cfPWV and CP were 0.38 (95% confidence interval: 0.19 to 0.59) and 0.61 (95% confidence interval: 0.04 to 0.83), respectively. Shared genetic factors accounted for 92% of the observed correlation (0.38) between cfPWV and CP.

CONCLUSIONS

These results suggest that the association between increased arterial stiffness and the propensity of the arterial wall to calcify is explained by a common genetic etiology and is independent of noncalcified atheromatous plaque and independent of BMD.

(Sub)clinical cardiovascular disease is associated with increased bone loss and fracture risk; a systematic review of the association between cardiovascular disease and osteoporosis

Introduction

Both cardiovascular disease and osteoporosis are important causes of morbidity and mortality in the elderly. The co-occurrence of cardiovascular disease and osteoporosis prompted us to review the evidence of an association between cardiovascular (CV) disease and osteoporosis and potential shared common pathophysiological mechanisms.

Methods

A systematic literature search (Medline, Pubmed and Embase) was conducted to identify all clinical studies that investigated the association between cardiovascular disease and osteoporosis. Relevant studies were screened for quality according to guidelines as proposed by the Dutch Cochrane Centre and evidence was summarized.

Results

Seventy studies were included in this review. Due to a large heterogeneity in study population, design and outcome measures a formal meta-analysis was not possible. Six of the highest ranked studies (mean n = 2,000) showed that individuals with prevalent subclinical CV disease had higher risk for increased bone loss and fractures during follow-up compared to persons without CV disease (range of reported risk: hazard ratio (HR) 1.5; odds ratio (OR) 2.3 to 3.0). The largest study (n = 31,936) reported a more than four times higher risk in women and more than six times higher risk in men. There is moderate evidence that individuals with low bone mass had higher CV mortality rates and incident CV events than subjects with normal bone mass (risk rates 1.2 to 1.4). Although the shared common pathophysiological mechanisms are not fully elucidated, the most important factors that might explain this association appear to be, besides age, estrogen deficiency and inflammation.

Conclusions

The current evidence indicates that individuals with prevalent subclinical CV disease are at increased risk for bone loss and subsequent fractures. Presently no firm conclusions can be drawn as to what extent low bone mineral density might be associated with increased cardiovascular risk.

Associations between vitamin D receptor genotypes and mortality in a cohort of older Dutch individuals

CONTEXT

Vitamin D receptor (VDR) polymorphisms are associated with a variety of diseases, which may translate into an effect on mortality.

OBJECTIVE

To investigate the associations between VDR gene variants and mortality among older people.

DESIGN

The analyses were conducted in a population-based, prospective cohort of the Longitudinal Aging Study Amsterdam. Adequate DNA analysis was performed in 923 men and women (≥65 years). We aimed to assess the associations between mortality and the VDR polymorphism FokI, three haplotypes of the Cdx2 and GATA polymorphisms, and three haplotypes of the BsmI, ApaI, and TaqI polymorphisms.

RESULTS

During the median follow-up of 10.7 years, 480 participants deceased (51%). Homozygosity for the Cdx2-GATA haplotype 1 allele was associated with a 30% higher mortality risk compared to the absence of alleles (hazard ratios (HR) 1.30, 95% confidence intervals (CI) 1.01-1.68). Adjustment for cardiovascular risk factors and 25-hydroxyvitamin D levels did not affect this HR. The number of copies of the Cdx2-GATA haplotype 1 allele was associated, although not significantly, with an increased risk of osteoporotic fractures (0 copies=reference, HR, 95% CI: 1 copy 2.01, 0.99-4.07 and 2 copies 1.81, 0.87-4.18). After adjustment for osteoporotic fractures, homozygosity for the Cdx2-GATA haplotype 1 allele was no longer associated with higher mortality risk (HR 1.08, 95% CI 0.83-1.41).

CONCLUSIONS

The Cdx2-GATA haplotype 1 allele was related to increased mortality risk, which may be partly explained by osteoporotic fractures. As the biological mechanism is uncertain and this study size is limited, our results should be interpreted as hypothesis generating.

Vitamin D receptor gene, biochemical bone markers and bone mineral density in Mexican women on dialysis

BACKGROUND

The influence of the Bsm1 polymorphism of the vitamin D receptor (VDR) gene on mineral and bone disorders in chronic kidney disease (CKD) is still under discussion. The aim of this study was to analyse the relationship between VDR polymorphism, bone mineral density (BMD), biochemical bone markers and clinical factors in women on peritoneal dialysis (PD) and haemodialysis (HD).

METHODS

In a cross-sectional study, 197 women (42 +/- 10 years; 25% with diabetes mellitus (DM); body mass index (BMI) 25.26 +/- 4.77 kg/m(2)) treated by PD (72%) or HD (28%) underwent measurements of BMD (measured at the calcaneus by quantitative ultrasound; expressed as T- and Z-scores) and plasma total calcium (tCa), intact parathyroid hormone 1-84 (iPTH), phosphorus, albumin, glucose, osteoprotegerin (OPG), fetuin-A, intact osteocalcin-49 and N-MID fragment 1-43 aa (N-MID osteocalcin) N-terminal propeptide of type 1 procollagen (PINP) and C-terminal telopeptide-beta aspartic acid (BCL). DNA was extracted from peripheral blood. PCR products were digested with Bsm1 to analyse VDR polymorphism.

RESULTS

The Z-score of BMD was -1.1 +/- 1.03. According to the values of osteopenia (T-score = -1.0), patients with higher BMD were younger, had lower frequency of amenorrhoea and diabetes and had higher serum creatinine and fetuin levels as well as lower levels of PINP. In a stepwise multivariate logistics analysis, osteopenia was associated with presence of genotype BB+Bb (OR = 3.26, P < or = 0.003) and age (OR = 0.95, P = 0.050). According to the B allele, bb: n = 126 (64%) and BB+Bb: n = 71(36%), group bb had significantly higher mean Z-scores (-0.97 +/- 1.0 vs -1.3+/-0.92; P < or = 0.021).

CONCLUSIONS

The high frequency of osteopenia observed in female CKD patients on dialysis is associated with age and genetic predisposition as revealed by its association to the Bsm1 VDR polymorphism.

Low bone mineral density at femoral neck is a predictor of increased mortality in elderly Japanese women

This study aimed to determine whether low bone mineral density (BMD) at the femoral neck independently predicts all-cause mortality in elderly Japanese women. A prospective cohort study of 271 women aged 67-89 years was conducted. A Cox proportional hazard model was used to examine independent associations between BMD and total mortality. During a 12-year follow-up period, the mortality risk (as measured by hazard ratio [HR]) was significantly increased in the three categories of baseline BMD (diagnostic criteria of osteoporosis, tertile of BMD, and quartile of BMD). After adjusting for major potential confounding variables for mortality, significantly increased mortality risks were found in subjects with osteoporosis (HR = 2.17, p = 0.032), in subjects in the lowest tertile (HR = 2.57, p = 0.007), and in subjects in the lowest quartile (HR = 3.13, p = 0.014], respectively. Our findings suggest that preventive strategies should be considered to increase and maintain high BMD at the femoral neck in the elderly women not only to prevent hip fractures but also probably to reduce mortality risk.

INTRODUCTION

Several longitudinal studies with Caucasian subjects have suggested that osteoporosis is associated with increased mortality. This study aimed to determine whether low bone mineral density (BMD) at the femoral neck independently predicts all-cause mortality in elderly Japanese community-dwelling women.

METHOD

A prospective cohort study of 271 women aged 67-89 years was conducted. A Cox proportional hazard model was used to examine independent associations between BMD at both the femoral neck and the trochanter and total mortality.

RESULTS

During a 12-year follow-up period, 81 of 271 women (29.9%) died. An independent and significant relationship was found between baseline BMD at the femoral neck and mortality risk. The mortality risk (as measured by HR) was increased by 2.80-fold (95% confidence interval [CI] 1.55-5.06; p < 0.01) in the subjects with osteoporosis or by 2.94-fold (95% CI 1.64-5.26; p < 0.001) in subjects in the lowest tertile or by 3.61-fold (95% CI 1.77-7.41; p < 0.001) in subjects in the lowest quartile of BMD, respectively. After adjusting for major potential confounding factors for mortality such as age, body mass index, blood pressure, blood variables, medical history, alcohol drinking, and smoking status, those in the subjects with osteoporosis (HR = 2.17 [95% CI 1.07-4.41], p = 0.032), in the lowest tertile (HR = 2.57 [95% CI 1.29-5.15], p = 0.007), or in the lowest quartile (HR = 3.13 [95% CI 1.26-7.73], p = 0.014] had a significantly increased risk of mortality. BMD measurement at the trochanter showed similar but weaker results.

CONCLUSIONS

Our findings suggest that preventive strategies should be considered to increase and maintain high BMD at the femoral neck in elderly subjects not only to prevent osteoporosis and its associated fractures but also probably to reduce mortality risk.

Association of plasma vitamin D levels with adiposity in Hispanic and African Americans

CONTEXT

Previous studies have suggested vitamin D insufficiency is associated with increased obesity; however, the relationship between 25-hydroxyvitamin D (25[OH]D) and 1,25-dihydroxyvitamin D (1,25[OH](2)D) and measures of adiposity has not been well characterized in minority populations.

OBJECTIVE

The objective of the study was to examine the relationship between levels of 25[OH]D and 1,25[OH](2)D and measures of adiposity in Hispanic and African-Americans at baseline and on change in these measures over time.

DESIGN AND SETTING

The Insulin Resistance Atherosclerosis (IRAS) Family Study examined 917 Hispanics and 439 African-Americans at baseline and again 5.3 yr later (n = 1081 at follow-up).

MAIN OUTCOME MEASURE

25[OH]D (nanograms per milliliter) and 1,25[OH](2)D (picograms per milliliter) were measured at baseline. Abdominal sc adipose tissue (SAT), visceral adipose tissue (VAT; both determined by computed tomography scan), and body mass index (BMI) were measured at baseline and follow-up.

RESULTS

25[OH]D was inversely associated with BMI, VAT, and SAT in both populations at baseline (P < 0.001). 25[OH]D was marginally inversely associated with baseline visceral fat to sc fat ratio in African-Americans (P = 0.049) but not Hispanics. 1,25[OH](2)D was inversely associated with BMI (P < 0.0001, P = 0.002) and VAT (P = 0.0005, P = 0.012) in Hispanics and African-Americans, respectively, whereas 1,25[OH](2)D was inversely associated with SAT in Hispanics (P < 0.0001) and with visceral fat to sc fat ratio in African-Americans (P = 0.02). Adjusting for 25[OH]D attenuated these associations; 1,25[OH](2)D remained associated with BMI in both populations (P < 0.05) and with SAT (P = 0.004) in Hispanics. No significant associations between 5-yr change in adiposity and 25[OH]D or 1,25[OH](2)D were seen.

CONCLUSIONS

Vitamin D levels were inversely associated with baseline BMI, SAT, and VAT in Hispanic and African-Americans but were not associated with 5-yr change in adiposity.

Candidate genes for respiratory disease associated with markers of inflammation and endothelial dysfunction in elderly men

BACKGROUND

Inflammation and endothelial dysfunction are important risk factors for cardiovascular disease (CVD). We hypothesized that candidate genes selected for a study of asthma and chronic obstructive pulmonary disorder (COPD) are associated with markers of systemic inflammation and endothelial dysfunction in an aging population.

METHODS

Plasma levels of circulating C-reactive protein (CRP), fibrinogen, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were obtained from 679 elderly male participants in the Normative Aging Study. Blood samples were analyzed for 202 single nucleotide polymorphisms (SNPs) in 25 candidate genes and included both haplotype tagSNPs and functional SNPs based on literature review. Data were stratified into discovery and replication cohorts for 2-stage analysis. In the discovery cohort, the relationship between biomarker level and genotype was analyzed using linear mixed effects with random intercepts for each subject and models were adjusted for age and BMI. A positive outcome in the discovery cohort was defined as a p-value <0.1 for the SNP. SNPs that met this criterion were analyzed in the replication cohort and confirmed for those which met a criterion of significance (p<0.025).

RESULTS

In our analyses, SNPs in the CRHR1, ITPR2, and VDR genes met significance criteria.

CONCLUSIONS

Our results suggest that genes thought to play a role in the pathogenesis of asthma and COPD may influence levels of serum markers of inflammation and endothelial dysfunction via novel SNP associations which have not previously been associated with cardiovascular disease.

Atherosclerosis and osteoporosis: age-dependent degenerative processes or related entities?

Osteoporosis and atherosclerosis, two multifactorial and degenerative entities, are major public health problems. These diseases accompany the aging process and share common risk factors. Furthermore, several common pathophysiological factors have been suggested. These include similar molecular pathways involving bone and vascular mineralization, estrogen deficiency, parathyroid hormone, homocysteine, lipid oxidation products, inflammatory process, as well as vitamin D and K. Moreover, the use of statins, biphosphonates, beta-blockers and experimental dual-purpose therapies based on the biological linkage of the above entities may simultaneously benefit bone loss and vascular disease. This review considers a potential link between osteoporosis and atherosclerosis beyond aging. These common factors may lead to appropriate treatment strategies.

Low bone mass is associated with carotid atherosclerosis in postmenopausal women: the Japanese Population-based Osteoporosis (JPOS) Cohort Study

We analyzed 609 women belonging to the JPOS study in a 10-year follow-up survey, to examine the association of osteoporosis with atherosclerosis. Osteoporosis or prevalent vertebral fracture at baseline was associated with increased intima-media thickness of the carotid bifurcation in postmenopausal women, adjusted for age, BMI, and other variables at baseline.

INTRODUCTION

Whether low bone mass predicts increased carotid atherosclerosis has not been fully investigated.

METHODS

In 2006, we conducted a 10-year follow-up survey of 1,040 women (follow-up rate: 68.6%). We analyzed 609 women > or =50 years old in 2006 without a history of cardiovascular or connective tissue diseases at baseline. BMD and evaluation of vertebral fracture at baseline were used. The intima-media thickness of carotid bifurcation (BIF-IMT) was measured by B-mode ultrasonography in 2006.

RESULTS

Adjusted BIF-IMT values of subjects with spine T-score > or =-1, between-2.5 and -1, and <-2.5 or prevalent vertebral fracture were 1.19 mm, 1.34 mm, 1.57 mm, respectively, in women with less than 10 years since menopause (YSM) (n = 159), 1.30 mm, 1.32 mm, 1.53 mm, in women with YSM > or =10 without a history of hypertension at baseline (n = 144) (both with p < 0.05 for linear trend). Those values among no versus prevalent vertebral fracture in women with YSM > or =10 were 1.40 mm, 1.66 mm with p < 0.05 (n = 202). Those associations were independent of age, BMI, total cholesterol, smoking and drinking habits, history of diabetes mellitus, and hypertension (for women with YSM < 10) at baseline.

CONCLUSION

Osteoporosis including prevalent vertebral fracture may be associated with carotid atherosclerosis in the first 10 years of postmenopausal women.

Genetic and environmental determinants of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels in Hispanic and African Americans

CONTEXT

Vitamin D deficiency is associated with many adverse health outcomes, yet little is known about the genetic epidemiology of vitamin D or its metabolites.

OBJECTIVE

Our objective was to examine the relationship among three vitamin D-related genes and levels of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)2D] in Hispanics (HAs) and African Americans (AAs).

DESIGN AND SETTING

The cross-sectional Insulin Resistance Atherosclerosis Family Study recruited and examined subjects in: Los Angeles, California (AAs; 513 individuals from 42 families); San Luis Valley (SLV), Colorado (HAs; 513 individuals from 30 families); and San Antonio (SA), Texas (HAs; 504 individuals from 58 families).

MAIN OUTCOME MEASURES

Plasma levels of 25(OH)D and 1,25(OH)2D were measured.

RESULTS

Levels of 25(OH)D were highest in SLV-HAs [18.3 +/- 7.7 ng/ml (45.7 +/- 19.2 nmol/liter)], lower in SA-HAs [14.6 +/- 6.4 ng/ml (36.4 +/- 16.0 nmol/liter)], and lowest in AAs [11.0 +/- 5.4 ng/ml (27.5 +/- 13.5 nmol/liter)]. Levels of 1,25(OH)2D were similar in AAs [43.5 +/- 13.9 pg/ml (113.1 +/- 36.1 pmol/liter)] and SLV-HAs [43.2 +/- 13.3 pg/ml (112.3 +/- 34.6 pmol/liter)], but higher in SA-HAs [48.6 +/- 17.0 pg/ml (126.4 +/- 44.2 pmol/liter)]. After adjusting for gender and age within the site, two single nucleotide polymorphisms (SNPs) in the vitamin D binding protein gene (DBP), rs4588 and rs7041, were associated with 25(OH)D, and one SNP in the DBP, rs4588, was associated with 1,25(OH)2D at all three study centers.

CONCLUSIONS

SNPs in the DBP are associated with levels of 25(OH)D and 1,25(OH)2D in HA and AA participants in the Insulin Resistance Atherosclerosis Family Study.

Genetic polymorphisms of vitamin D receptor (VDR) in Fabry disease

Fabry disease, an X-linked inborn error of metabolism, is characterized by multi-organ involvement including cardiac signs of left ventricular hypertrophy and abnormal intima-medial (IMT) thickening of arteries, progressive renal failure, neurological involvement, and more. The vitamin D receptor (VDR) and an enzyme producing vitamin D3 result in an autocrine loop with direct effects on blood vessels. The purpose of this study is to assess VDR polymorphisms (BsmI, FokI, ApaI, and TaqI) relative to clinically important disease parameters using a disease-specific severity score (MSSI) and haplotype analysis. There were statistically significant differences between females (43% of 74 patients) and males in MSSI total scores, and in general and neurologic sub-scores. There appears to be a protective effect of the TaqI tt genotype so that there were significantly lower scores in clinical categories between those with the tt genotype versus those with the TT genotype. Multivariate models of haplotypes with MSSI scores reveal that T-A-f-B and t-a-F-b haplotypes of the VDR gene polymorphisms are significantly associated with variation in the Fabry phenotype. Despite the limitations of using the MSSI score as a clinical correlate, these results are provocative and further studies in larger cohorts with more males are recommended.

Vitamin D and cardiovascular disease risk

PURPOSE OF REVIEW

Despite our understanding of how to prevent and treat traditional cardiovascular risk factors, cardiovascular disease remains the leading cause of death of both men and women in the US. Thus, there is widespread interest in a number of emerging nontraditional risk factors for the detection of early cardiovascular disease in order to implement aggressive preventive therapies. 25-Hydroxyvitamin D deficiency has been identified as a potential novel cardiovascular disease risk factor. This review outlines what is known about the association of 25-hydroxyvitamin D levels and cardiovascular disease risk.

RECENT FINDINGS

Low 25-hydroxyvitamin D levels have been associated with the cardiovascular disease risk factors of hypertension, obesity, diabetes mellitus and the metabolic syndrome, as well as cardiovascular disease events including stroke and congestive heart failure. Studies suggest vitamin D deficiency may be a contributor to the development of cardiovascular disease potentially through associations with diabetes or hypertension.

SUMMARY

Vitamin D deficiency is easy to screen for and easy to treat with supplementation. Further larger observational studies and randomized clinical trials are, however, needed to determine whether vitamin D supplementation could have any potential benefit in reducing future cardiovascular disease events and mortality risk.

Decreased bone mineral density is correlated with increased subclinical atherosclerosis in older, but not younger, Mexican American women and men: the San Antonio Family Osteoporosis Study

An association has been reported between cardiovascular disease (CVD) and osteoporosis, perhaps attributable to the presence of common risk factors. To assess this possibility, we measured areal bone mineral density (BMD) and carotid artery intimal medial thickness (IMT), a measure of preclinical atherosclerosis, in 535 women and 335 men from the San Antonio Family Osteoporosis Study. Variance decomposition methods were used to determine whether cross-sectional measures of areal BMD (measured by dual-energy X-ray absorptiometry) of the total hip, spine, and forearm were correlated with IMT, serum lipids, and/or C-reactive protein (CRP), a marker of inflammation, after accounting for known environmental factors. We observed significant inverse correlations of IMT and BMD at all bone sites in women >60 years of age (P < 0.001) and modest positive correlations (not significant) of IMT on hip BMD (P < 0.1) in women <60 years of age. Similarly, we observed negative correlations between IMT and forearm BMD in men >60 years of age (P < 0.001) and positive correlations in men <60 years of age (P = 0.05). Variation in risk factors for CVD, including serum levels of low- and high-density lipoprotein cholesterol, low-density lipoprotein particle size, triglycerides, paraoxonase 1 activity, and CRP did not account for the relationship between BMD and IMT in either older or younger men or women. In summary, our results demonstrate that decreased BMD is correlated with increased IMT in older (but not younger) Mexican American men and women, independent of serum CVD risk factors.

Vascular calcification in middle age and long-term risk of hip fracture: the Framingham Study

Osteoporosis and atherosclerosis frequently occur in the same individuals and may share similar pathogenic mechanisms. This study examined the relation between severity of aortic calcification in middle-age years and subsequent risk of hip fracture in women and men in the population-based Framingham Study.

INTRODUCTION

We assessed vascular calcification in women and men in middle age and risk of hip fracture at advanced age.

MATERIALS AND METHODS

Participants included 2499 Framingham cohort members (mean age, 61 yr; range, 47-80 yr). Semiquantitative methods were used to determine severity of abdominal aortic calcification on baseline radiographs. Information on potential confounding factors was obtained from study examinations conducted at, or before, baseline radiography. Hip fractures were ascertained by active surveillance and confirmed by medical records.

RESULTS

Thirty-five-year cumulative incidence of hip fracture was 16% in women and 5% in men with prevalent aortic calcification at baseline (score 1+) and 14% in women and 4% in men without aortic calcification (score 0). Hazard ratios (HRs) and 95% CIs for hip fracture did not increase from the lowest to the highest category of aortic calcification. HRs were 1.0, 1.2 (95% CI, 0.9-1.8), 1.2 (95% CI, 0.7-1.9), 1.1 (95% CI, 0.7-1.7), and 1.4 (95% CI, 0.8-2.3) in women (p for trend = 0.44) and 1.0, 1.8 (95% CI, 0.8-3.8), 1.8 (95% CI, 0.7-4.6), 1.5 (95% CI, 0.6-3.9), and 1.2 (95% CI, 0.2-5.7) in men (p for trend = 0.29) for aortic calcification scores 0 (reference), 1-4, 4-5, 6-10, and 11+, respectively. However, aortic calcification score was strongly associated with increased risk of death (p for trend < 0.0001 in women and men). HRs (95% CIs) for mortality from the lowest to highest aortic calcification score were 1.0, 1.6 (1.4-1.9), 1.7 (1.4-2.1), 1.8 (1.5-2.2), and 2.1 (1.7-2.6) for women, and for men were 1.0, 1.4 (1.1-1.6), 1.4 (1.2-1.8), 1.6 (1.3-2.0), and 1.9 (1.5-2.5).

CONCLUSIONS

Vascular calcification in middle-aged adults does not increase long-term hip fracture risk.

Association between systemic calcified atherosclerosis and bone density

Both atherosclerosis and osteoporosis are responsible for significant morbidity and mortality, are independent predictors of cardiovascular disease (CVD) events, and may share common regulatory mechanisms as well as histopathology. Multiple reports of weak or null relationships between traditional CVD risk factors and calcified atherosclerosis have heightened interest in novel predictors of arterial calcium. One such hypothesis is for an inverse relationship between bone mineral density (BMD) and calcified coronary atherosclerosis. Although contrary findings have been reported, the majority of cross-sectional and all prospective studies have demonstrated a significant inverse association between arterial calcium deposits and BMD. The few studies that include men are equivocal, and, to date, no study has investigated the relationship between BMD and systemic arterial calcium. The aim of this study was to test the hypothesis that lumbar BMD is significantly associated with the presence of arterial atherosclerotic calcium in the carotid, coronary, and iliac vascular beds as well as the aorta.

Vitamin D receptor polymorphisms and diseases

The vitamin D endocrine system is central to the control of bone and calcium homeostasis. Thus, alterations in the vitamin D pathway lead to disturbances in mineral metabolism. Furthermore, a role for vitamin D has been suggested in other diseases, like cancer, diabetes and cardiovascular disease. Expression and nuclear activation of the vitamin D receptor (VDR) are necessary for the effects of vitamin D. Several genetic variations have been identified in the VDR. DNA sequence variations, which occur frequently in the population, are referred to as "polymorphisms" and can have biological effects. To test whether there is a linkage between VDR polymorphisms and diseases, epidemiological studies are performed. In these studies, the presence of a variation of the gene is studied in a population of patients, and then compared to a control group. Thus, association studies are performed, and a link among gene polymorphisms and diseases can be established. Since the discovery of VDR polymorphisms a number of papers have been published studying its role in bone biology, renal diseases, diabetes, etc. The purpose of this review is to summarize the vast amount of information regarding vitamin D receptor polymorphisms and human diseases, and discuss its possible role as diagnostic tools.

Genetic determinants of carotid ultrasound traits

Atherosclerosis is a complex disease with various intermediate phenotypes that are themselves complex and influenced by many factors. Through the use of carotid ultrasound techniques, the intermediate stages of vascular disease can be imaged and studied for association with potential genetic determinants. In this article we review the most recent available data (reports published since 2004) on the genetic determinants of atherosclerosis, as measured by one-, two-, and three-dimensional ultrasonography of the carotid arteries. In general, associations are disparate and modest. For intima-media thickness, promising associations have been found for both TNFRSF1A R92Q and PPARG P12A, but associations also differed in the same individuals depending on the specific ultrasound trait studied (eg, linear intima-media thickness versus total plaque volume in carotid arteries). Some of the challenging issues for future studies include accounting for gene-environment interactions, sex-specific associations, and the distinctiveness of different carotid ultrasound measures.

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.