Association between vitamin D receptor gene polymorphisms and bone mineral density in Chinese women

Effects of Isoflavonoid and Vitamin D Synergism on Bone Mineral Density-A Systematic and Critical Review

Phytoestrogens are non-steroidal plant compounds, which bind to α and β estrogen receptors, thereby causing specific effects. The best-known group of phytoestrogens are flavonoids, including isoflavonoids-genistein and daidzein. They play a role in the metabolism of bone tissue, improving its density and preventing bone loss, which contributes to reducing the risk of fractures. Vitamin D is found in the form of cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2) and is traditionally recognized as a regulator of bone metabolism. The aim of this review was to evaluate the synergistic effect of isoflavonoids and vitamin D on bone mineral density (BMD). The MEDLINE (PubMed), Scopus and Cochrane databases were searched independently by two authors. The search strategy included controlled vocabulary and keywords. Reference publications did not provide consistent data regarding the synergistic effect of isoflavonoids on BMD. Some studies demonstrated a positive synergistic effect of these compounds, whereas in others, the authors did not observe any significant differences. Therefore, further research on the synergism of isoflavonoids and vitamin D may contribute to a significant progress in the prevention and treatment of osteoporosis.

Modulation of the vitamin D/vitamin D receptor system in osteoporosis pathogenesis: insights and therapeutic approaches

Osteoporosis is a prevalent bone disorder characterized by low bone mineral density (BMD) and deteriorated bone microarchitecture, leading to an increased risk of fractures. Vitamin D (VD), an essential nutrient for skeletal health, plays a vital role in maintaining bone homeostasis. The biological effects of VD are primarily mediated through the vitamin D receptor (VDR), a nuclear receptor that regulates the transcription of target genes involved in calcium and phosphate metabolism, bone mineralization, and bone remodeling. In this review article, we conduct a thorough literature search of the PubMed and EMBASE databases, spanning from January 2000 to September 2023. Utilizing the keywords "vitamin D," "vitamin D receptor," "osteoporosis," and "therapy," we aim to provide an exhaustive overview of the role of the VD/VDR system in osteoporosis pathogenesis, highlighting the most recent findings in this field. We explore the molecular mechanisms underlying VDR's effects on bone cells, including osteoblasts and osteoclasts, and discuss the impact of VDR polymorphisms on BMD and fracture risk. Additionally, we examine the interplay between VDR and other factors, such as hormonal regulation, genetic variants, and epigenetic modifications, that contribute to osteoporosis susceptibility. The therapeutic implications of targeting the VDR pathway for osteoporosis management are also discussed. By bringing together these diverse aspects, this review enhances our understanding of the VD/VDR system's critical role in the pathogenesis of osteoporosis and highlights its significance as a potential therapeutic target.

Relevance of Serum Levels and Functional Genetic Variants in Vitamin D Receptor Gene among Saudi Women with Gestational Diabetes Mellitus

Background: This study explored the association between ApaI-TaqI Single Nucleotide Polymorphisms (SNPs) in a Vitamin D receptor (VDR) and the risk of Gestational Diabetes Mellitus (GDM) in Saudi women, along with the serum levels of vitamin D. Methods: Ninety women with GDM and 90 non-GDM women were enrolled, based on the inclusion and exclusion criteria for pregnant women enrolled in a single-center study. Blood samples were retrieved from 180 pregnant women using ethylenediaminetetraacetic acid (EDTA) tubes. Serum samples were used to measure the vitamin D, 25-hydroxyvitamin D (25(OH)D or calcidiol), and lipid profiles. Blood was used to measure the hemoglobin A1c levels and to isolate the DNA. The polymerase chain reaction (PCR) was performed for the ApaI (rs79785232), BsmI (rs1544410), FokI (rs2228570), and TaqI (rs731236) SNPs in the VDR gene using restriction fragment length polymorphism analysis. Validation was performed using Sanger sequencing. Statistical analyses were performed between the patients with and without GDM using various statistical software packages. Results: The Hardy-Weinberg equilibrium analysis was statistically significant (p > 0.05). The ApaI, BsmI, and TaqI SNPs were associated with alleles, genotypes, and different genetic models (p < 0.05). Vitamin D levels were associated with deficient levels (p = 0.0002), as well as with a normal and overweight body mass index (p = 0.0004). When vitamin D levels were measured with GDM covariates, the fasting plasma glucose (FPG) (p = 0.0001), postprandial blood glucose (PPBG) (p < 0.0001), oral glucose tolerance test (OGTT)-1 h (p = 0.005), high-density lipoprotein (p = 0.022), and low-density lipoprotein cholesterol (LDLc) (p = 0.001) levels were significantly different. When similar vitamin D levels were measured for each genotype, we confirmed that the ApaI SNP was associated with sufficient levels (p < 0.0001), whereas the BsmI, FokI, and TaqI (p < 0.05) were associated with insufficient levels. The logistic regression model confirmed that the first hour of the OGTT (p = 0.005) was strongly associated with GDM, whereas the analysis of variance confirmed that FPG and PPBG (p < 0.05) were strongly associated with all the SNPs evaluated in the VDR gene. Additionally, the second hour of the OGTT (p = 0.048) and LDLc (p = 0.049) were associated with the ApaI and FokI SNP. Moreover, the first hour OGTT (p = 0.045) and lipid profile parameters (p < 0.05) were associated. Haplotype analysis revealed positive associations among the examined SNPs, which seemed compatible with the hypothesis that variants and combinations of multiple SNP genotypes enhance the risk of GDM in women. Haplotype analysis revealed that different combinations of alleles, such as AGCC, CATT, CGTC, AGTC, and CATT (p < 0.05), were strongly associated. The linkage disequilibrium (LD) analysis showed a strong association with all combinations (p < 0.05). Among the gene-gene interactions, all possible combinations showed a positive association (p < 0.05). Conclusions: Low vitamin D levels were observed in women with GDM. The ApaI, BsmI, and TaqI SNPs were associated with genotype and allele frequencies (p < 0.05). Vitamin D and the SNPs in the VDR gene were associated, according to the ANOVA, logistic regression, haplotype analysis, LD analysis, and the generalized multifactor dimensionality reduction model (p < 0.05).

Genetic association of vitamin D receptor gene with female infertility

BACKGROUND

Infertility is defined as failure to achieve a clinical pregnancy after 12 months of unprotected intercourse. It affects 15% of couples globally and 22% of couples within Pakistan. Female infertility can be caused by numerous genetic or environmental factors including hormone imbalances and exposure to chemicals or radiation. The prevalence of vitamin D deficiency among the adult population was reported to be 14-59% with a higher prevalence in Asian countries. Furthermore, the expression of Vitamin D receptor (VDR) can play a vital role in the reproductive organs of females. Hence, the aim of our present study was to check the association of VDR polymorphisms with infertile females. For this purpose, blood samples were collected for genotyping of four known VDR mutations [FokI (rs2228570), TaqI (rs731236), ApaI (rs7975232), and BsmI (rs1544410)] via PCR-based RFLP assay.

RESULTS

Genotyping indicated that FokI, TaqI, and ApaI are associated with infertility (p = 0.004*, p = 0.013*, and p = 0.033*, respectively). However, BsmI did not show any significance. Multinomial regression analysis indicated that FokI heterozygous genotypes increase the risk of infertility by 2.5 times (hetero: OR = 2.5, 95%, p = 0.001*) as compared to wild type. Heterozygous genotypes of TaqI and ApaI were found to play a protective role and reduce the risk of infertility by 58 and 52%, respectively [TaqI: OR = 0.42, 95%, p = 0.004*, ApaI: OR = 0.48, 95%, p = 0.01*, respectively] as compared to wild type. Multinomial logistic regression analysis was also performed for allelic data as well.

CONCLUSION

Thus, it could be summarized that among the studied polymorphisms of VDR, FokI SNP greatly increased the risk of infertility, while TaqI and ApaI genotypes protect from infertility. However, BsmI does not influence the risk of infertility in Pakistani females.

Vitamin D Receptor Gene Polymorphisms Affect Osteoporosis-Related Traits and Response to Antiresorptive Therapy

The present study analyzed the effect of vitamin D receptor (VDR) gene polymorphisms (ApaI, TaqI, BsmI, FokI, and Cdx2) on bone mineral density (BMD), biochemical parameters and bone turnover markers, fracture prevalence, and response to three types of antiresorptive therapy (estrogen-progesterone, raloxifene, and ibandronate) in 356 postmenopausal women from Slovakia. Association analysis revealed a significant effect of BsmI polymorphism on lumbar spine BMD, serum osteocalcin (OC), and β-CrossLaps levels. While ApaI and Cdx2 polymorphisms were associated with OC and alkaline phosphatase, TaqI polymorphism affected all turnover markers. ApaI, TaqI, and BsmI genotypes increased the risk of spinal, radial, or total fractures with odds ratios ranging from 2.03 to 3.17. Each of therapy types evaluated had a beneficial effect on all osteoporosis-related traits; however, the VDR gene affected only ibandronate and raloxifene treatment. ApaI/aa, TaqI/TT, and BsmI/bb genotypes showed a weaker or no response to ibandronate therapy in femoral and spinal BMD. The impact of aforementioned polymorphisms on turnover markers was also genotype dependent. On the contrary, only TaqI and BsmI polymorphisms influenced raloxifene therapy, even only in lumbar spine BMD. These results point to the potential of using the VDR gene in personalized pharmacotherapy of osteoporosis.

Do Vitamin D receptor gene polymorphisms affect bone mass density in men?: A meta-analysis of observational studies

The signs of aging in humans can often be detected through a decrease in bone mass density (BMD). The decrease in BMD as a risk of osteoporosis is often only seen in women, but not in men, even though men also have a risk of osteoporosis which can affect their well-being. We conducted study searches through databases such as PubMed, EBSCO, ProQuest, Willey Online, Science Direct, and SAGE. We performed analysis on four types of Vitamin D receptor polymorphisms: BsmI, ApaI, FokI, and TaqI from 14 potential studies involving men. We found that several genetic analysis models of BsmI and FokI significantly affected BMD in men: BB vs bb in whole body BMD (SMD = 0.43, 95% CI = [0.12-0.75], p = 0.0008, BB vs Bb in whole body BMD (SMD = -1.38, 95% CI = [-1.87 to 0.88], p < 0.00001), and FF+Ff vs ff spine BMD (SMD = 0.59, 95% CI = 0.13-1.05], p = 0.001), even after adjusting for comorbidities as confounding variables. The present meta-analysis showed that BsmI and FokI polymorphisms of the VDR gene were correlated with decreased BMD in men which may contribute to the aging process and well-being.

Does the VDR gene polymorphism influence the efficacy of denosumab therapy in postmenopausal osteoporosis?

INTRODUCTION

One of the challenges of personalized medicine is a departure from traditional pharmacology toward individualized, genotype-based therapies. Postmenopausal osteoporosis is a prevalent condition requiring intensive treatment, whose effects are measurable only after a long time, and the goal is bone fracture prevention. This study aimed to determine the influence of VDR gene variation on anti-osteoporotic one-year treatment with denosumab in 63 Polish women with postmenopausal osteoporosis.

MATERIALS AND METHODS

The correlation between bone mineral density (BMD) of the lumbar vertebral column (L1-L4) and femoral neck, and genotype distributions for the ApaI, BsmI, FokI, and TaqI variants of the VDR gene was analyzed. Bone fractures during denosumab therapy were also investigated.

RESULTS

In the case of the Bsml polymorphism, female patients with BB and Bb genotypes had statistically significantly higher values of BMD and T-score/Z-score indicators, which persisted after a year of denosumab treatment. Our results indicated that the Bsml polymorphism contributes to better bone status, and, consequently, to more efficient biological therapy. The study did not reveal significant differences between changes (delta) in BMD and genotypes for the analyzed VDR gene loci. In the entire study group, one bone fracture was observed in one patient throughout the yearlong period of denosumab therapy.

CONCLUSIONS

BB and Bb genotypes of the Bsml polymorphism of the VDR gene determine higher DXA parameter values both before and after one-year denosumab therapy in postmenopausal women with osteoporosis.

Association of Single Nucleotide Polymorphisms in the VDR and CYP27B1 Genes with Risk of Developing Vitamin D3 Deficiency

This study was carried out to investigate the relationship between common variants in two vitamin D pathway genes (VDR and CYP27B1) and vitamin D3 serum levels. In this study, serum vitamin D metabolite levels were measured in the blood samples of 200 patients with alopecia areata. Then, single nucleotide polymorphisms (SNPs) in VDR and CYP27B1 were analyzed using polymerase chain reaction (PCR)-sequencing. Sixty-three variations were observed in these genes (42 variations in CYP27B1 and 21 variations in VDR). A significant difference in Rs1544410 (odds ratio: 7, P < 0.0005) and rs4646536 (odds ratio: 4.043, P < 0.0005) variants was found between the patients and controls. The study showed the relationship between the two polymorphisms, Rs1544410 (odds ratio: 7, 95% CI, 1–8) and rs4646536 (odds ratio: 4.043, 95% CI, 3–14.038) on the genes VDR and CYP27B1, respectively, with increased risk of developing vitamin D3 insufficiency in the Iranian population. Therefore, SNPs in the VDR and CYP27B1 genes can be considered as prognostic biomarkers of the risk of developing vitamin D3 deficiency.

3'-UTR Polymorphisms of Vitamin B-Related Genes Are Associated with Osteoporosis and Osteoporotic Vertebral Compression Fractures (OVCFs) in Postmenopausal Women

As life expectancy increases, the prevalence of osteoporosis is increasing. In addition to vitamin D which is well established to have an association with osteoporosis, B vitamins, such as thiamine, folate (vitamin B9), and cobalamin (vitamin B12), could affect bone metabolism, bone quality, and fracture risk in humans by influencing homocysteine/folate metabolism. Despite the crucial role of B vitamins in bone metabolism, there are few studies regarding associations between B vitamin-related genes and osteoporosis. In this study, we investigated the genetic association of four single nucleotide polymorphisms (SNPs) within the 3’-untranslated regions of vitamin B-related genes, including TCN2 (encodes transcobalamin II), CD320 (encodes transcobalamin II receptor), SLC19A1 (encodes reduced folate carrier protein 1), and SLC19A2 (encodes thiamine carrier 1), with osteoporosis and osteoporotic vertebral compression fracture (OVCF). We recruited 301 postmenopausal women and performed genotyping of CD320 rs9426C>T,TCN2 rs10418C>T, SLC19A1 rs1051296G>T, and SLC19A2 rs16862199C>T using a polymerization chain reaction-restriction fragment length polymorphism assay. There was a significantly higher incidence of both osteoporosis (AOR 5.019; 95% CI, 1.533–16.430, p < 0.05) and OVCF (AOR, 5.760; 95% CI, 1.480–22.417, p < 0.05) in individuals with genotype CD320 CT+TT and high homocysteine concentrations. Allele combination analysis revealed that two combinations, namely CD320 C-TCN2 T-SLC19A1 T-SLC19A2 C (OR, 3.244; 95% CI, 1.478–7.120, p < 0.05) and CD320 T-TCN2 C-SLC19A1 G-SLC19A2 C (OR, 2.287; 95% CI, 1.094–4.782, p < 0.05), were significantly more frequent among the osteoporosis group. Our findings suggest that SNPs within the CD320 gene in 3´-UTR may contribute to osteoporosis and OVCF occurrences in some individuals. Furthermore, specific allele combinations of CD320, TCN2, SLC19A1, and SLC19A2 may contribute to increased susceptibility to osteoporosis and OVCF.

Association between polymorphisms in GGPS1 and RANKL genes and postmenopausal osteoporosis in Romanian women

Objectives: This study aimed to assess the relationship between bone mineral density, fragility fractures, fracture risk and polymorphisms of two osteoporosis-candidate genes (GGPS1 and RANKL) in Romanian women with postmenopausal osteoporosis. Methods: An analytical, prospective, transversal, observational, case-control study on 364 postmenopausal women, of which 228 were previously diagnosed with osteoporosis, was carried out between June 2016 and August 2017 in Cluj Napoca, Romania. Clinical data and blood samples were collected from all study participants. Polymorphisms in GGPS1 and RANKL genes were genotyped using TaqMan SNP Genotyping assays, run on a QuantStudio 3 real-time PCR machine. Results: The CT genotype in GGPS1 rs10925503 was associated with significant lower bone mineral density values at lumbar spine and femoral neck sites and a higher fracture risk compared to controls. No significant association was found between genotypes of RANKL rs2277439 with bone mineral density or fracture risk compared to the healthy controls. Conclusions: Our study showed a strong association between low bone mineral density and genotype CT of GGPS1 rs10925503 polymorphisms. No association was found for RANKL rs2277439 polymorphism.

Association between rs12742784 polymorphism and hip fracture, bone mineral density, and EPHB2 mRNA expression levels in elderly Chinese women

Objective: This study aimed to determine the association between rs12742784 polymorphism in the non-coding area and hip fracture, bone mineral density (BMD), and EPHB2 mRNA expression levels in elderly Chinese women.Methods: We investigated 250 Chinese women (mean age: 63.5 ± 8.3 years) including 123 hip fracture patients and 127 non-fracture controls. All participants underwent clinical examination to meet the inclusion criteria. Lumbar and hip BMD were detected by dual-energy X-ray absorptiometry. rs12742784 polymorphism was determined by restriction fragment length polymorphism and EPHB2 mRNA expression levels were measured by real-time polymerase chain reaction.Results: Distribution of rs12742784 genotypes agreed with Hardy-Weinberg equilibrium. The frequency of the CT + TT genotype was significantly associated with decreased risk of hip fracture (adjusted odds ratio = 0.57, p < 0.01) after adjusting for age and body mass index, and with increased BMD and EPHB2 mRNA expression levels. The T allele of the rs12742784 single nucleotide polymorphism (SNP) was a protective factor for hip fracture (adjusted odds ratio = 0.56, p < 0.01).Conclusion: rs12742784 polymorphism was associated with EPHB2 mRNA expression levels, BMD, and hip fracture in Chinese women. The T allele of the rs12742784 SNP was a protective factor for osteoporosis and hip fracture.

Association of vitamin D receptor gene polymorphism (TaqI and Apa1) with bone mineral density in North Indian postmenopausal women

Vitamin D receptor (VDR) gene has an important role as a candidate gene for the regulation of bone mass in osteoporosis. However, its association with bone mineral density (BMD) is controversial and has not been established in different ethnic populations. To enhance the understanding of VDR gene polymorphism in the context of BMD, we investigated the plausible genetic association of TaqI and ApaI polymorphism with BMD in North Indian postmenopausal women with osteoporosis.254 osteoporotic women (Age 55.82 ± 6.91) and 254 postmenopausal non osteoporotic women (Age 54.76 ± 6.26) were included in the study. VDR TaqI and ApaI polymorphism were determined by PCR (polymerase chain reaction) and RFLP (restriction fragment length polymorphism). BMD was assessed by dual energy X-ray absorptiometry (DXA) at the lumbar spine (L₁-L₄), hip, forearm and femoral neck. The average BMD with TT genotype was significantly lower at lumbar spine, hip and forearm. The Frequency of TT genotype and t allele was significantly high in osteoporotic women when compared with controls. The average BMD with Aa genotype was higher in ApaI. Furthermore, comparison of frequency distribution of genotype and allele for VDR ApaI between osteoporotic patients and controls did not show any significant difference. Our findings revealed that TaqI gene TT genotype was associated with low BMD in North Indian osteoporotic women. Moreover, TT genotype and t allele associated significantly with osteoporosis in postmenopausal women. Therefore, VDR TaqI gene is an important determinant of risk factor for osteoporosis.

Polymorphisms of miR-146a, miR-149, miR-196a2, and miR-499 are associated with osteoporotic vertebral compression fractures in Korean postmenopausal women

Genetic factors have been shown to be a small but significant predictor for osteoporosis and osteoporotic fracture risk. We performed a case-control association study to determine the association between miR-146a, miR-149, miR-196a2, and miR-499 polymorphisms and osteoporotic vertebral compression fracture (OVCF) susceptibility. In total, 286 unrelated postmenopausal Korean women (57 with OVCFs, 55 with non-OVCFs, and 174 healthy controls) were recruited. All subjects underwent dual energy X-ray absorptiometry to determine BMD at the lumbar spine and femoral neck. We focused on four single nucleotide polymorphisms (SNPs) of pre-miRNA sequences including miR-146aC>G (rs2910164), miR-149T>C (rs2292832), miR-196a2T>C (rs11614913), and miR-499A>G (rs3746444). Genotype frequencies of these four SNPs were determined using polymerase chain reaction-restriction fragment length polymorphism analysis. The TT genotype of miR-149aT>C was less frequent in subjects with OVCFs, suggesting a protective effect against OVCF risk (Odds ratio [OR], 0.435; 95% confidence interval [CI], 0.22-0.85, p = 0.014), whereas the miR-146aCG/ miR-196a2TC combined genotype was more frequent in OVCF patients (OR, 5.163; 95%CI, 1.057-25.21, p = 0.043), suggesting an increase in OVCF risk. Additionally, combinations of miR-146a, -149, -196a2, and -449 showed a significant association with increased prevalence of OVCFs in postmenopausal women. In particular, the miR-146aG/-149T/-196a2C/-449G allele combination was significantly associated with an increased risk of OVCF (OR, 35.01; 95% CI, 1.919-638.6, p = 0.001). Our findings suggest that the TT genotype of miR-149aT>C may contribute to decreased susceptibility to OVCF in Korean postmenopausal women. Conversely, the miR-146aCG/ miR-196a2TC combined genotype and the miR-146aG/-149T/-196a2C/-449G allele combination may contribute to increased susceptibility to OVCF. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:244-253, 2018.

Use of Genetic Algorithm Combinational Single-nucleotide Polymorphisms Could Modify the Association of Blood Lead Levels and Bone Matrix Density

BACKGROUND

Previous studies have not explored the relationship between a single gene and a single disease. Our study aims to investigate the association of multiple genotypes with blood lead levels and bone matrix density (BMD) by using genetic algorithms.

METHODS

Our research focused on 506 employees (245 males and 261 females) of a lead battery factory in Taiwan. We collected data on their BMD, blood lead level, and 6 SNPs (ACE, alpha-adducin, Bsm, Tag, Apa, and ALAD); these factors were analyzed using discrete binary particle swarm optimization (DBPSO) and logistic regression analysis.

RESULTS

We found no association between blood lead level and bone density, which may be due to the relatively young age of this population (mean age = 45.1 years). However, the genotype that contained both Bsm type bb and ALAD type 1-1 may play an important role in protecting against lower bone density among these employees.

CONCLUSIONS

In conclusion, this study found that the Bsm and ALAD genes influence bone density among lead workers. However, the mechanism and exact relationship between these two genes and bone density require further investigation.

Lack of association between vitamin D receptor polymorphisms ApaI (rs7975232) and BsmI (rs1544410) and osteoporosis among the Han Chinese population: A meta-analysis

In this study, we aimed to assess the relationship between vitamin D receptor gene polymorphisms and osteoporosis in the Han Chinese population. Articles regarding associations between vitamin D receptor polymorphisms (ApaI rs7975232 and BsmI rs1544410) and osteoporosis were retrieved from databases in November 2014. Eligible studies were tested by the Hardy-Weinberg equilibrium. The odds ratio and 95% confidence interval (95% CI) were analyzed to evaluate the strength of the associations. Pooled effect estimates were derived using a fixed-effect model and a random-effect model according to the heterogeneity of the test results. A subgroup analysis by study type and a sensitivity analysis based on studies that conform to the Hardy-Weinberg equilibrium and studies with postmenopausal women as participants were performed. This meta-analysis involved 15 eligible studies including 1580 cases and 1389 controls. The pooled estimated odds ratios in the dominant and additive genetic models were 0.73 (95% CI: 0.46-1.14, p=0.17) and 1.01 (95% CI: 0.77-1.33, p=0.81), respectively, for rs7975232 and 1.01 (95% CI: 0.81-1.26, p=0.91) and 1.01 (95% CI: 0.77-1.33, p=0.92), respectively, for rs1544410. The subgroup analysis showed that regardless of the dominant or additive genetic model, the effect of pooled odds ratios for rs7975232 and rs1544410 was insignificant. The sensitivity analysis also showed that the pooled effect was not significantly changed. In conclusion, no evidence of association is apparent between polymorphisms of vitamin D receptor genes and osteoporosis risk in the Han Chinese population.

Vitamin D Level Between Calcium-Phosphorus Homeostasis and Immune System: New Perspective in Osteoporosis

Vitamin D is a key molecule in calcium and phosphate homeostasis; however, increasing evidence has recently shown that it also plays a crucial role in the immune system, both innate and adaptive. A deregulation of vitamin D levels, due also to mutations and polymorphisms in the genes of the vitamin D pathway, determines severe alterations in the homeostasis of the organism, resulting in a higher risk of onset of some diseases, including osteoporosis. This review gives an overview of the influence of vitamin D levels on the pathogenesis of osteoporosis, between bone homeostasis and immune system.

Association between the vitamin D receptor gene polymorphism and osteoporosis

The influence of the vitamin D receptor (VDR) gene for the risk of osteoporosis remains to be elucidated. The aim of the present study was to understand the distribution of various single-nucleotide polymorphisms (SNPs) within the VDR gene and its association with the risk of osteoporosis. In total, 378 subjects without a genetic relationship were recruited to the study between January 2013 and July 2015. The subjects were divided into three groups, which were the normal (n=234), osteoporosis (n=65) and osteoporosis with osteoporotic fracture (n=79) groups. Three pertinent SNPs of the VDR gene rs17879735 (ApaI, Allele A/a, SNP C>A) were examined with polymerase chain reaction-restriction fragment length polymorphism. The bone mineral density (BMD) of the lumbar spine (L2-L4), femoral neck, Ward's and Tro was measured using dual-energy X-ray absorptiometry. The distributions of genotype frequencies aa, AA and Aa were 48.68, 42.86 and 8.46%, separately. Following analysis of each site, BMD, body mass index (BMI) and age, BMD for each site was negatively correlated with age (P<0.01) and positively correlated with BMI (P<0.01). Correction analysis revealed that there were significant differences in the Ward's triangle BMD among each genotype (P<0.05), in which the aa genotype exhibited the lower BMD (P<0.05). No significant difference was identified among the different genotypes in the occurrence of osteoporosis with osteoporotic fracture (P>0.05). In conclusion, these indicated that the VDR gene ApaI polymorphisms had an important role in the osteoporosis risk.

Evaluation of common variants in CNR2 gene for bone mineral density and osteoporosis susceptibility in postmenopausal women of Han Chinese

Postmenopausal osteoporosis is a major health problem with important genetic factors in postmenopausal women. We thoroughly evaluated the relationship of CNR2 polymorphisms with osteoporosis in a cohort of 1032 osteoporosis patients and 2089 healthy controls from Han Chinese postmenopausal women. Statistically significant differences, depending on different genotypes, were presented.

INTRODUCTION

Osteoporosis is a major health problem in postmenopausal women, which is a multifactorial disease in which genetic determinants are modulated by hormonal, environmental, and nutritional factors. An important clinical risk factor in the pathogenesis of osteoporosis is the presence of genetic polymorphism in susceptibility genes. The aim of our study was to investigate whether CNR2 gene, which attributes to osteoporosis susceptibility in some populations, is associated with bone mineral density (BMD) or osteoporosis in Han Chinese postmenopausal women.

METHODS

We examine 39 SNPs covering the region of CNR2 gene in 3121 Han Chinese postmenopausal women, consisting of 1032 osteoporosis patients and 2089 healthy controls, to evaluate the association with BMD and osteoporosis.

RESULTS

We found that rs4237 and rs2501431 were significantly associated with BMD and osteoporosis (corrected p = 0.020085 and 0.017199) in our sample, and the TT genotype of rs2501431 and the AA genotype of rs4237 had lower lumbar spine BMD and femoral neck BMD compared with the other genotypes. Additionally, analyses by haplotypes indicated that two haplotype blocks, containing rs4237 and rs2501431 respectively, in the CNR2 gene significantly associated with BMD and osteoporosis (both global permutation p < 0.001), and a risk haplotype (ATTT) in the block of rs3003336-rs2501431-rs2502992-rs2501432 had almost 4-fold increase in the cases.

CONCLUSIONS

Our results provide further supportive evidence for an important role of CNR2 gene in the etiology of osteoporosis and suggest that it may be a genetic risk factor for BMD and osteoporosis in Han Chinese postmenopausal women.

A polymorphism at the translation start site of the vitamin D receptor gene is associated with the response to anti-osteoporotic therapy in postmenopausal women from southern Italy

The present study investigated the effect of two single nucleotide polymorphisms (SNPs) of the vitamin D receptor (VDR) gene, rs1544410 A/G and rs2228570 C/T, in modulating bone mineral density (BMD) and the response to treatment with bisphosphonates or strontium ranelate in postmenopausal osteoporosis (PMO). Four hundred eighteen postmenopausal women from Southern Italy treated with bisphosphonates or strontium ranelate for three years were enrolled and stratified according to their genotype. Changes in BMD were expressed as the delta t-score (Δt-score). Allelic frequencies for rs1544410 A/GSNP were 11.2% AA, 50.0% GA and 38.8% GG; for rs2228570 C/TSNP were 54.8% CC, 39.5% TC and 5.7% TT. TT carriers showed a lower t-score than TC and CC (both p < 0.02) genotypes and were more responsive to the therapy when compared to both TC (p < 0.02) and CC (p < 0.05) carriers. Specifically, TT carriers receiving alendronate demonstrated a significant improvement of the Δt-score compared to TC and CC (both p < 0.0001) carriers. After adjustment for confounders, the Δt-score showed evidence of a statistically significant positive association with TT in all treatments considered. Therapy response was independent of rs1544410 A/G SNP; instead, rs2228570 C/TSNP was associated with a better response to antiresorptive treatment, thus suggesting that the therapy for PMO should be personalized.

The influence of vitamin D receptor genetic variants on bone mineral density and osteoporosis in Chinese postmenopausal women

Growing evidence indicates that the vitamin D receptor (VDR) gene is an important candidate gene for influencing the development of osteoporosis. The aim of the study was to evaluate the potential association between genetic variants of VDR gene and bone mineral density (BMD) and osteoporosis in Chinese postmenopausal women. The study included 970 Chinese postmenopausal women at the postmenopausal osteoporosis (482) and healthy controls (488). The BMD of lumbar spine (L_2–4 anterior-posterior view), femoral neck hip, and total hip was evaluated using the Norland XR-46 dual energy X-ray absorptiometry (DEXA). The genotypes of VDR genetic variants were determined by the created restriction site-PCR (CRS-PCR) and confirmed by DNA sequencing methods. Our data indicated that the VDR p.Glicine (Gly)14 alanine (Ala) and p.histidine (His) 305 glutanine (Gln) genetic variants were statistically associated with adjusted femoral neck hip BMD, adjusted lumbar spine BMD, and adjusted total hip BMD (P values < 0.05). Results from this study suggest that the VDR p.Gly14Ala and p.His305Gln genetic variants are significantly associated with BMD decrease in Chinese postmenopausal women and might be used as molecular markers for assessing the risk of BMD and osteoporosis.

Association analysis between g.18873C>T and g.27522G>A genetic polymorphisms of OPG and bone mineral density in Chinese postmenopausal women

Several studies report that the OPG is an important candidate gene in the pathogenesis of osteoporosis. This study aimed to detect the potential association of OPG gene polymorphisms with osteoporosis in postmenopausal women. We recruited 928 subjects containing 463 with primary postmenopausal osteoporosis and 465 healthy volunteers as controls. The BMD of neck hip, lumbar spine (L_2–4), and total hip were assessed by dual-energy X-ray absorptiometry (DEXA). Through the created restriction site-polymerase chain reaction (CRS-PCR), PCR-restriction fragment length polymorphism (PCR-RFLP), and DNA sequencing methods, the g.18873C>T and g.27522G>A have been investigated. As for g.18873C>T, our data indicated that subjects with CC genotype have significantly higher BMD value than those of CT and TT genotypes (all P values < 0.05). As for g.27522G>A, the BMD values of subjects with GG genotype were significantly higher than those of GA and AA genotypes (all P values < 0.05). Our findings suggest that the OPG g.18873C>T and g.27522G>A genetic polymorphisms are associated with the decreased risk for osteoporosis in Chinese postmenopausal women.

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.

The relationship between the g.27450A>T genetic variant of OPG gene and osteoporosis in Chinese postmenopausal women

The objective of this study is to evaluate the relationship between the g.27450A>T genetic variant of osteoprotegerin (OPG) gene and osteoporosis in Chinese postmenopausal women. A total of 886 subjects were enrolled in this study. The femoral neck hip, lumbar spine (L2-4), and total hip bone mineral density (BMD) were detected by dual-energy X-ray absorptiometry (DEXA). The genotyping of the g.27450A>T genetic variant of OPG gene was investigated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods. Significant differences in the femoral neck hip, lumbar spine (L2-4), and total hip BMD among different genotypes were found, and the subjects with AA genotype were significantly higher than those of AT and TT genotypes (P<0.05). The allele-A could be a decreased risk factor for osteoporosis. Results from this study support that the g.27450A>T genetic variant of OPG gene has potential relationship with BMD and osteoporosis in Chinese postmenopausal women.

Vitamin D receptor gene polymorphisms and risk of osteoarthritis: A meta-analysis

The vitamin D receptor (VDR) gene polymorphisms have been reported to be involved in the development of many musculoskeletal disorders, including osteoarthritis (OA). However, results were inconsistent and there is no definite conclusion regarding the association between any VDR polymorphism and the risk of OA. In this study, we conducted a meta-analysis to determine whether BsmI, TaqI, and ApaI polymorphisms in the VDR gene are associated with OA susceptibility. Literature research was performed using PubMed and EMBASE databases. Studies illustrating the association between the three VDR polymorphisms and OA were included, and their qualities were assessed using Newcastle–Ottawa scale. Eight eligible studies, recruiting 1626 cases and 2024 controls were identified. Their methodological qualities were generally good, with scores ranging from 6 to 8 points. However, throughout all summary analyses, which were performed for multiple categories and on four contrasts (allele contrast, contrast of homozygotes, recessive and dominant models), none of the VDR BsmI, TaqI, and ApaI gene polymorphisms were found to be significantly associated with the risk of OA. On the other hand, there was no significant publication bias. Results from this meta-analysis suggested that the VDR BsmI, TaqI, and ApaI gene polymorphisms might not be important predictors of OA. More studies further investigating these associations, especially taking into account of gene–gene, gene–environment interactions, and other confounding factors are warranted.

Vitamin D receptor gene polymorphisms and the risk of rickets among Asians: a meta-analysis

AIMS

To evaluate the association between vitamin D receptor (VDR) gene polymorphisms and the risk of rickets among Asians.

METHODS

Eligible studies were included in our meta-analysis by searching PubMed, Embase, Cochrane and China National Knowledge Infrastructure databases according to a predefined criteria. A random effects model was used to calculate the combined ORs and its corresponding 95% CI.

RESULTS

16 studies were recruited for the analysis of the association between VDR BsmI (rs1544410), TaqI (rs731236), FokI (rs2228570) and ApaI (rs7975232) gene polymorphisms and the risk of rickets among Asians, most of whom were from China. B allele/BB genotype was associated with the susceptibility of rickets (p=0.017 and 0.044, respectively), and bb genotype was associated with lower risk of rickets (p=0.033). F allele/FF genotype was associated with the susceptibility of rickets (p<10(-4)), and ff genotype was associated with lower risk of rickets (p<10(-4)). AA genotype was associated with the onset of rickets (p=0.044). No significant association was observed between TaqI polymorphism the risk of rickets. A allele/aa genotype was not associated with the risk of rickets. No evidence of publication bias was observed.

CONCLUSIONS

B allele/BB genotype at the BsmI site, F allele/FF genotype at the FokI site and AA genotype at the ApaI site may be risk factors for the onset of rickets among Asians; bb genotype at the BsmI site and ff genotype at the FokI site may be protective factors against the risk of rickets among Asians.

4q22.1 contributes to bone mineral density and osteoporosis susceptibility in postmenopausal women of Chinese Han population

Osteoporosis is a multifactorial disease in which genetic determinants are modulated by hormonal, environmental and nutritional factors. An important clinical risk factor in the pathogenesis of osteoporosis is the presence of genetics polymorphism in/around susceptibility genes/regions. This study explored whether the region of 4q22.1, which confers risk of developing osteoporosis in some populations, associated with bone mineral density and osteoporosis susceptibility in postmenopausal women of Han Chinese. We investigated 32 SNPs with minor allele frequencies ≥0.05 between 20 kb upstream and 20 kb downstream (40 kb window) of rs6532023, mapping in the 4q22.1 region, which was reported to be significantly associated with osteoporosis in previous studies. We found that rs6532023 was significantly associated with bone mineral density and osteoporosis (corrected p = 0.015) in our sample, including 440 cases and 640 controls, and allele G was supposed as a risk factor while T worked as a protective factor. Further genotype association analyses suggested a similar pattern (corrected p = 0.040). Additionally, analyses by haplotypes indicated that a haplotype block rs7683315-rs6532023-rs1471400-rs1471403 in the region associated with bone mineral density and osteoporosis (global p = 0.032), and risk haplotype A-G-G-C had almost 1.5-fold increased in the cases. To our knowledge, this is the first report to examine 4q22.1 region polymorphisms and osteoporosis in Han Chinese. Our results provide further evidence for an effect of the region of 4q22.1 on the etiology of osteoporosis and suggest that 4q22.1 may be a genetic risk factor for bone mineral density and osteoporosis.

Association between interleukin-6 gene polymorphisms and bone mineral density: a meta-analysis

BACKGROUND

Many studies have examined the association between interleukin-6 (IL-6) gene polymorphisms and bone mineral density (BMD). However, the results remain conflicting. To assess the relationship more precisely, a meta-analysis was performed.

METHODS

The PubMed, Embase, Chinese BioMedical Literature (CBM), Wanfang, and China National Knowledge Infrastructure (CNKI) database were searched for relevant articles published up to March 2013. Weighted mean difference (WMD) and 95% confidence interval (95% CI) were calculated using a fixed-effects or random-effects model.

RESULTS

A total of 16 articles with 11,957 subjects were investigated in this meta-analysis. Overall, -634C/G polymorphism was significantly associated with BMD at the femoral neck (WMD, -0.016 g/cm(2); 95% CI, -0.028 to -0.003 g/cm(2)), lumbar spine (WMD, -0.049 g/cm(2); 95% CI, -0.069 to -0.030 g/cm(2)), and whole body (WMD, -0.023 g/cm(2); 95% CI, -0.037 to -0.009 g/cm(2)) for GG versus CC+CG. In subgroup analyses stratified by ethnicity, individuals carrying -634GG genotype had a significantly lower mean BMD at any skeletal site examined, compared with individuals with -634CC or -634CG genotype in Asian populations. For -174G/C polymorphism, the BMD differences between CC+CG and GG genotype were 0.004 g/cm(2) at the distal radius (95% CI, 0.004 to 0.005 g/cm(2)), 0.011 g/cm(2) at the trochanter (95% CI, 0.002 to 0.020 g/cm(2)), and 0.017 g/cm(2) at the Ward's triangle (95% CI, 0.003 to 0.032 g/cm(2)). No significant publication bias was observed in either the -634C/G or -174G/C polymorphism.

CONCLUSIONS

This suggests that there are modest effects of the -634C/G and -174G/C polymorphisms on BMD. Large-scale and well-designed studies are required to further investigate gene-gene and gene-environment interactions on IL-6 polymorphisms and BMD in various populations.

Association of polymorphisms in the vitamin D receptor promoter with idiopathic short stature

The genetic alterations of vitamin D receptor (VDR) are related with the growth of long bone. There were a lot of reports regarding an association of polymorphisms in the VDR promoter with many disorders, but not with idiopathic short stature (ISS). We investigated the association of them with ISS. A total of 50 subjects, including 29 ISS patients and 21 healthy controls with their heights within the normal range was recruited. We selected two single nucleotide polymorphisms (SNPs) from VDR promoter (rs11568820 at the Cdx-2 binding site upstream of exon 1e and rs4516035 at -1012 upstream of exon 1a) as candidates, respectively. In genotype analysis, the frequency of A/A genotype at the Cdx-2 binding site locus (rs11568820) upstream of exon 1e of VDR was decreased to 6.9% in ISS patients (28.6% in controls) (P = 0.027). The genetic variation at the Cdx-2 binding site of VDR promoter can be a contributing factor of growth of height.

Vitamin D receptor (VDR) gene polymorphism influences the risk of osteoporosis in postmenopausal women of Northwest India

SUMMARY

The influence of VDR gene for the risk of osteoporosis has remained inconclusive. VDR gene polymorphism in relation to BMD in postmenopausal women of Northwest India revealed a susceptibility haplotype AGT. Possession of this haplotype exacerbates the risk of osteoporosis by 2.8 times, which manifests in recessive mode of inheritance.

PURPOSE

The purpose of this study is to understand the influence of coordinated effect of various single nucleotide polymorphisms (SNPs) within vitamin D receptor (VDR) gene for the risk of osteoporosis, which has remained undefined so far.

METHODS

Four pertinent SNPs of VDR gene, i.e., rs2228570, rs1544410, rs17879735, and rs731236 were examined with polymerase chain reaction-restriction fragment length polymorphism in dual energy X-ray absorptiometry verified 188 osteoporotics, 115 osteopenics, and 147 normal postmenopausal women of Northwest India.

RESULTS

Minor allele 'T' of rs2228570 showed significant influence for the risk of osteoporosis (OR 1.60, 95%CI 1.16-2.20, P=0.004) and also in dominant (OR 2.32, 95%CI 1.47-3.64, P=0.0006) and additive model (OR 2.41, 95%CI 1.49-3.87, P=0.0006) after Bonferroni correction. Minor allele (T) of rs2228570 showed an allele dose effect with BMD of L1-L4 (P=0.009) and FN (P=0.036). Disease association analysis exposed a susceptibility haplotype AGT which influences the risk of osteopenia (OR 2.04, 95%CI 1.03-4.08, P=0.036) and osteoporosis (OR 2.90, 95%CI 1.61-5.38, P=0.00005) after adjusting the effects of age, BMI and years since menopause. This haplotype is significantly associated with BMDs at lumbar spine (P=0.0001) and femoral neck (P=0.016).

CONCLUSION

In-depth analysis of this haplotype with other methods of Wald statistics and Akaike information criterion confirmed that carriers of each unit of this haplotype AGT increases the risk of osteoporosis by a factor of 2.80±0.34 (β±SE) which manifests (P=0.1 × 10⁻⁶) in its recessive mode of inheritance.

The relationship between osteoprotegerin gene polymorphisms and bone mineral density in Chinese postmenopausal women

Previous evidence supports that the osteoprotegerin (OPG) gene is one of the most important candidate genes for influencing the pathogenesis of osteoporosis. The objective of this study was to investigate the relationship between OPG gene polymorphisms and osteoporosis in Chinese postmenopausal women. A total of 764 subjects were included in this study. The bone mineral density (BMD) in the lumbar spine (L2-4), neck hip and total hip was determined by dual-energy X-ray absorptiometry (DEXA). The g.19190C>A and g.25602A>G SNPs were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), created restriction site PCR (CRS-PCR) and DNA sequencing methods. As for g.19190C>A, our data suggested that the BMD value of lumbar spine (L2-4), neck hip and total hip for subjects with CC genotype was significantly higher than that of CA and AA genotypes (P<0.05). No significant difference was detected between the association of g.25602A>G genotypes with spine BMD and neck hip BMD, while total hip BMD almost reached the significant level (P=0.063). These findings provide more evidence that the SNPs in OPG gene could affect BMD and osteoporosis, and the allele-A of g.19190C>A and allele-G of g.25602A>G genetic variants are associated with increased risk for osteoporosis in Chinese postmenopausal women.

Association between osteoprotegerin genetic variants and bone mineral density in Chinese women

Osteoprotegerin gene (OPG) is one of the most important candidate genes for osteoporosis. The aim of this study was to assess the association between the single nucleotide polymorphisms (SNPs) of OPG gene and bone mineral density (BMD). A total of 706 Chinese postmenopausal women were enrolled in this study. OPG gene variants were genotyped through created restriction site-polymerase chain reaction (CRS-PCR) and verified using DNA sequencing methods. The lumbar spine (L2-4), total hip and femoral neck were evaluated for BMD. Two genetic variants (g.18910G>A and g.27406C>T) were detected in this study. Our data indicated that the significant differences of spine BMD, neck hip BMD and total hip BMD were detected among different g.27406C>T genotype, subjects with the genotype CC were significantly higher than those of genotype CT and TT. However, the g.18910G>A polymorphism was not significantly associated with spine BMD, neck hip BMD and total hip BMD in the studied subjects. Results from this study indicated that OPG gene variants were associated with BMD in Chinese postmenopausal women. These findings will be useful to analyze the role of OPG gene in osteoporosis in the further studies.

Association between osteoprotegerin genetic variants and osteoporosis in Chinese postmenopausal women

The objective of this study was to evaluate the association of single nucleotide polymorphisms (SNPs) of osteoprotegerin gene (OPG) with bone mineral density (BMD) and osteoporosis. A total of 338 Chinese postmenopausal women with primary osteoporosis and 367 healthy controls were enrolled. The lumbar spine (L₂₋₄), total hip and femoral neck hip of BMD were assessed by dual-energy X-ray absorptiometry (DEXA). OPG genetic variants were genotyped through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), created restriction site-PCR (CRS-PCR) and DNA sequencing methods. In this study, the g.18861A>G and g.25548C>T SNPs were detected and our data suggested that the significant differences of spine BMD, femoral neck hip BMD and total hip BMD were found among different g.18861A>G genotype, subjects with the AA genotype were significantly higher than those of AG and GG genotypes (p < 0.05). The g.25548C>T variant was not significantly associated with spine BMD, femoral neck hip BMD and total hip BMD (p > 0.05), while almost reached at the significant level in total hip BMD (p = 0.061). These findings suggeste that OPG gene variants are related to BMD and osteoporosis in Chinese postmenopausal women.