Fractures of the proximal femur: correlation with vitamin D receptor gene polymorphism

Evaluation of Association Studies and an Updated Meta-Analysis of VDR Polymorphisms in Osteoporotic Fracture Risk

Background: Several studies have examined the association between vitamin D receptor (VDR) polymorphisms and osteoporotic fracture risk; however, the results are not uniform. Furthermore, many new articles have been published, and therefore, an updated meta-analysis was performed to further explore these issues.

Objectives: The aim of the study was to investigate the association between VDR, BsmI, ApaI, TaqI, FokI, and Cdx2 polymorphisms and osteoporotic fracture risk.

Methods: The odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association between VDR BsmI, ApaI, TaqI, FokI, and Cdx2 polymorphisms and the risk of osteoporotic fracture. We also used the false-positive reporting probability (FPRP) test and the Venice criteria to evaluate the credibility of the statistically significant associations.

Results: Overall, this study found that the VDR ApaI and BsmI polymorphisms significantly increased the risk of osteoporotic fracture in European countries and America, respectively. However, when sensitivity analysis was performed after excluding low-quality and Hardy–Weinberg disequilibrium (HWD) studies, it was found that only individuals with the double-mutated genotype have an increased risk of osteoporotic fracture in European countries. In addition, when the credibility of the positive results was assessed, it was found that the positive results were not credible.

Conclusion: This meta-analysis indicates that there may be no significant association among the polymorphisms of VDR BsmI, ApaI, TaqI, FokI, and Cdx2 and the risk of osteoporotic fracture. The increased risk of osteoporotic fracture is most likely due to false-positive results.

Vitamin D receptor Bsm I polymorphism and osteoporosis risk in postmenopausal women: a meta-analysis from 42 studies

OBJECTIVE

This study aimed to quantitatively summarize the evidence for VDR BsmI gene polymorphism and osteoporosis risk in postmenopausal women.

MATERIALS AND METHODS

The PubMed, EMBASE, Weipu, CNKI, and Wanfang databases were searched for eligible studies. Case-control studies containing available genotype frequencies of B/b were chosen, and odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of this association.

RESULTS

4485 osteoporosis and 5490 controls were identified in our meta-analysis. In the stratified analysis, a significant association was observed between VDR BsmI gene polymorphism and osteoporosis susceptibility in Caucasians (additive model: OR = 0.809, 95% CI 0.678~0.965, p = 0.019; recessive model: OR = 0.736, 95% CI 0.568~0.955, p = 0.021; and co-dominant model: bb vs. BB OR = 0.701, 95% CI 0.511~0.962 p = 0.028), and we failed to find any significant relationship in Asians.

CONCLUSION

The present meta-analysis suggests that VDR BsmI genotype is associated with increased risk of postmenopausal osteoporosis in Caucasians but not in Asians. To draw comprehensive and true conclusions, further prospective studies with larger numbers of participants worldwide are needed to examine associations between VDR BsmI polymorphism and osteoporosis in postmenopausal women.

Vitamin D receptor (VDR) gene FokI, BsmI, ApaI, and TaqI polymorphisms and osteoporosis risk: a meta-analysis

Background

Osteoporosis is a disease of the bones in which the density of the bones decreases. The prevalence of this disease greatly varies in different populations of the world. Numerous studies have been investigated VDR gene polymorphisms as osteoporosis risk in different ethnic groups. In present meta-analysis, the aim is to find out the role of VDR gene polymorphisms (FokI, BsmI, ApaI, and TaqI) in osteoporosis risk.

Methods

Suitable case-control studies for present meta-analysis were retrieved from four electronic databases. Open Meta-Analyst program was used for statistical analyses.

Results

Studies investigated BsmI (65 studies; 6880 cases/8049 controls), ApaI (31 studies; 3763 cases/3934 controls), FokI (18 studies; 1895 cases/1722 controls), and TaqI (26 studies; 2458 cases/2895 controls) polymorphisms that were included in the present meta-analysis. A significant association was found between the dominant model of FokI (ORff + Ffvs.FF = 1.19, 95% CI = 1.04–1.36, p = 0.01, I2 = 39.36%) in the overall analysis and recessive model of the Caucasian population of TaqI polymorphism (ORTT + Ttvs.tt = 1.35, 95% CI = 1.11–1.63, p = 0.002, I2 = 50.07%) with osteoporosis. On the other hand, no such effect is found in any other genetic models and in any other gene polymorphisms of the overall analyses or sub-group analyses.

Conclusion

In conclusion, the authors found that the dominant model of FokI in the overall analysis and recessive model of TaqI in the Caucasian population are significantly associated with the development of osteoporosis.

Vitamin D receptor gene and risk of fracture in postmenopausal women: a meta-analysis

OBJECTIVE

Fracture is the major clinical outcome of osteoporosis. The vitamin D receptor (VDR) gene is thought to be a candidate gene for osteoporosis. Many genetic studies have suggested an association of VDR polymorphisms and fracture risk, but evidence remains conflicting. The aim of this study was to evaluate the genetic effect of the BsmI, TaqI, ApaI and FokI polymorphisms in the VDR gene on fracture risk in postmenopausal women.

METHODS

Relevant studies were identified from the following electronic databases: PubMed, Embase, and Web of Science before September 2013. Statistical analysis was performed by using the software STATA 12.0. A total 1975 fracture cases and 4565 controls in 14 studies with a total of 16 eligible comparisons were identified for data analysis.

RESULTS

No evidence of relationship between the VDR BsmI, TaqI, ApaI or FokI polymorphisms and fracture risk was observed with any genetic model in postmenopausal women (BsmI: b vs. B: odds ratio (OR) 1.07, 95% confidence interval (CI) 0.90-1.29; TaqI: T vs. t: OR 0.89, 95% CI 0.68-1.15; ApaI: A vs. a: OR 0.91, 95% CI 0.76-1.08; FokI: F vs. f: OR 1.20, 95% CI 0.76-1.90).

CONCLUSION

This meta-analysis suggests that ApaI, BsmI, TaqI and FokI polymorphisms may be not associated with the risk of fracture in postmenopausal women. Further studies in a larger sample population are required to confirm this finding.

Association of vitamin D receptor BsmI gene polymorphism with risk of osteoporosis: a meta-analysis of 41 studies

Vitamin D receptor (VDR) BsmI gene polymorphism has been reported to be strongly associated with osteoporosis risk in some studies. However, the results from those studies are still conflicting. We performed a meta-analysis of studies relating the VDR BsmI gene polymorphism to the risk of osteoporosis. The search was performed in the databases of PubMed, Embase, Cochrane Library and CBM-disc (China Biological Medicine Database) as of October 1, 2011, and the eligible investigations were recruited for this meta-analysis. Forty-one investigations were identified for the meta-analysis of association between VDR BsmI gene polymorphism and osteoporosis risk. There lacked an association between VDR BsmI gene polymorphism and osteoporosis risk for overall populations, Caucasians and Asians (overall populations: B vs b: p = 0.65, BB vs (Bb + bb): p = 0.14, bb vs (BB + Bb): p = 0.86; Caucasians: B vs b: p = 0.65, BB vs (Bb + bb): p = 0.38, bb vs (BB + Bb): p = 0.83; Asians: B vs b: p = 0.87, BB vs (Bb + bb): p = 0.62, bb vs (BB + Bb): p = 0.66). In conclusion, VDR BsmI B/b gene polymorphism is not associated with the susceptibility of osteoporosis in overall populations, Caucasians, and Asians.

BsmI, TaqI, ApaI and FokI polymorphisms in the vitamin D receptor (VDR) gene and risk of fracture in Caucasians: a meta-analysis

CONTEXT

Vitamin D receptor (VDR) gene polymorphisms have been strongly associated with bone mineral density in some studies. However, in a recent meta-analysis, no relationship of the VDR BsmI or TaqI polymorphism and fracture risk was found in the meta-analysis of published data.

OBJECTIVE AND DESIGN

Our meta-analysis studied whether a relationship exists between BsmI, TaqI, ApaI and FokI polymorphisms in the VDR gene and risk of fracture.

DATA SOURCES

Relevant studies were identified from the following electronic databases: MEDLINE, EMBASE and Current Contents before January 2010.

DATA SYNTHESIS

This meta-analysis included 17 studies with a total of 21 eligible comparisons, which included 2112 fracture cases and 4521 controls. All of these studies reported on Caucasians. The combined results based on all studies showed that fracture cases had a significantly lower frequency of bb genotype of BsmI [odds ratio (OR) = 0.87, 95% confidence interval (CI)=0.76, 0.98]. When stratifying by fracture type, we found that (1) hip fracture cases had a significantly lower frequency of bb genotype of BsmI (OR=0.82, 95% CI=0.70, 0.97); (2) hip fracture cases had a significantly lower frequency of Tt genotype of TaqI (OR=0.65, 95% CI=0.43, 0.97); (3) hip fracture cases had a significantly higher frequency of tt genotype of TaqI (OR=1.74, 95% CI=1.05, 2.91); (4) vertebral fracture cases had a significantly higher frequency of Aa genotype of ApaI (OR=1.63, 95% CI=1.03, 2.59). No significant difference was found in any genotype of FokI.

CONCLUSION

Our meta-analysis suggests that there is a modest but statistically significant association between the BsmI bb genotypes and fracture.

Epidemiology of osteoporotic fractures in Brazil: what we have and what we need

The epidemiology of osteoporotic fractures varies widely among countries and is primarily related to differences in the population and utilization of public healthcare services. Since 1994, over 200 studies about osteoporosis and fractures have been conducted in Brazil, among which 60 have described the current epidemiological status. This work is a compilation of studies published in scientific journals (PubMed, MedLine, Lilacs, SciELO Database) with the respective highlights. Overall, these studies show moderate incidence of hip fracture in subjects over 50 years old. However, the prevalence of all types of bone fragility fracture is higher, ranging from 11% to 23.8%. In addition, there is a high incidence of recurrent falls, which are the main extra-skeletal factor associated with these fractures. According to the national studies, 12 months after femoral fractures, the mortality rate ranged between 21.5% and 30%, and there was also a high rate of physical impairment, deterioration of the quality of life and excessive burden to the healthcare system. Considering its high prevalence and associated mortality and physical impairment, osteoporosis and its main consequence, bone fragility fractures, must be considered a major public health problem in our country.

FRAX TM: construindo uma ideia para o Brasil

Diferenças genéticas, raciais e antropométricas, bem como da composição corporal, densidade óssea, dieta, atividade física e outros hábitos de vida, contribuem para explicar as divergências na incidência e prevalência de baixa densidade óssea e fraturas em diversos países do mundo. Recentemente, foi desenvolvida uma ferramenta, denominada FRAX TM, para aglutinar os fatores clínicos de risco (genéticos e ambientais) e a densidade óssea, a fim de quantificar a probabilidade de fratura osteoporótica nos próximos dez anos. Em breve, ela será utilizada para indicação de tratamento em pacientes de risco. No entanto, atualmente, está disponível somente para uso em algumas populações que possuem banco de dados prospectivos e consistentes - o que não inclui o Brasil. Este estudo teve o objetivo de fazer uma revisão dos estudos epidemiológicos nacionais e internacionais para melhor compreender peculiaridades e diferenças de fatores clínicos de risco, densidade óssea e probabilidade de fratura entre essas populações. Os autores concluíram que se faz necessária a obtenção de mais dados epidemiológicos representativos da população brasileira para utilização da ferramenta FRAX TM. Para isso, os estudos brasileiros deverão possuir características adequadas, como o delineamento prospectivo, avaliação da qualidade de vida, mortalidade e incapacidade física após as fraturas, levando em consideração a expectativa de vida da população brasileira e a análise de custos diretos e indiretos relacionados às fraturas por osteoporose. À luz do conhecimento atual, a utilização de qualquer um dos bancos de dados das populações, disponibilizadas pelo FRAX TM, não é recomendada no Brasil.

Vitamin D receptor gene BsmI and TaqI polymorphisms and fracture risk: a meta-analysis

INTRODUCTION

Fracture is the major clinical outcome of osteoporosis. The vitamin D receptor (VDR) gene is thought to be a candidate gene for osteoporosis. Many genetic studies have suggested an association of VDR polymorphisms and osteoporosis, but evidence remains conflicting.

MATERIALS AND METHODS

We searched published studies from 1996 to September 2005 through PubMed and evaluated the genetic effect of the BsmI and TaqI polymorphism of VDR on fracture risk in a meta-analysis. Thirteen studies with a total of 20 eligible comparisons (1632 fracture cases and 5203 controls) were analyzed with fixed and random effects models.

RESULT

No evidence of relationship between the VDR BsmI or TaqI polymorphism and fracture risk was observed with any genetic model. The odds ratio (95% confidence interval) of b-allele versus B-allele was 0.98 (0.86-1.12) with random effects calculations. There was significant between-study heterogeneity. Small studies did not differ significantly from larger ones.

CONCLUSION

No relationship of the VDR BsmI or TaqI polymorphism and fracture risk was found in the meta-analysis of published data.

Vitamin D receptor gene polymorphism in rheumatoid arthritis and associated osteoporosis

Rheumatoid arthritis (RA) is commonly associated with decreased bone mineral density (BMD) due to numerous factors. BsmI polymorphism of the vitamin D receptor (VDR) gene has been implicated in the pathogenesis of osteoporosis. Vitamin D has several immunomodulatory effects and thus may play a role in the course of arthritis. However, little data is available on the possible relationship between RA and VDR gene polymorphisms. In this study, the frequency of BsmI polymorphism genotypes were compared with that found in other countries. In this study, 64 RA patients and 40 healthy controls were tested for VDR gene BsmI polymorphism genotypes. Frequencies of B and b alleles were associated with markers of bone metabolism and RA. Among control subjects, the frequency of the BB genotype is relatively high (27.5%). In RA with secondary osteopenia/osteoporosis the BB genotype was more rare, the bb was more common than in control subjects. Markers of bone metabolism were associated with the B allele. RA patients carrying the B allele had lower BMD and increased bone loss over 1 year. The B allele was also correlated with increased osteoclast and osteoblast function, as determined by the assessment of biochemical markers of bone metabolism. Rheumatoid factor titer, which is an independent marker for disease progression in RA, was higher in bb patients. Our data suggest, that the imbalance in B and b allele expression may be involved in the pathogenesis of RA-associated osteoporosis. The possible involvement of vitamin D and VDR gene polymorphisms in the development and progression of RA needs further elucidation.

Relation of collagen type I alpha 1 (COLIA 1) and vitamin D receptor genotypes to bone mass, turnover, and fractures in early postmenopausal women and to hip fractures in elderly people

Background: In a previous study, we showed an association between the vitamin D receptor (VDR) gene BsmI restriction fragment polymorphism and peak bone mass in young Finnish adults. Design: The previous finding prompted us to study the relationship of the same polymorphism, as well as of the polymorphism in the Sp1 binding site of the collagen type I alpha 1 (COLIA 1) gene, to bone mineral density (BMD). BMD was measured by dual-energy X-ray absorptiometry and adjusted for age, weight, height, and lifestyle factors. Also studied was the relationship of VDR and COLIA 1 genotypes to markers of bone turnover [serum osteocalcin, type I procollagen carboxy- (PICP), and aminoterminal (PINP) propeptide, and type I collagen carboxyterminal telopeptide (ICTP)] and bone fractures in 513 early postmenopausal women (1-5 years postmenopausal), as well as hip fractures in 172 very old people. Results: The BB, Bb, and bb genotypes of the VDR gene, as well as the SS, Ss, and ss genotypes of the COLIA 1 gene, were distributed similarly among 402 early postmenopausal women with osteopenia in the lumbar spine and among 111 women with normal BMD (P=0.12 for VDR, P=0.53 for COLIA 1). There was no relation between the VDR and COLIA 1 genotypes and lumbar spine BMD among osteopenic women, among normal women, or in the combined study population. Among the women with vertebral osteopenia, the femoral neck BMD did not associate significantly with the VDR or COLIA 1 polymorphisms. The frequencies of the different VDR and COLIA 1 genotypes were similar among women with or without a history of a low-energy fracture. There was a borderline association between the VDR genotype and serum osteocalcin concentrations, with the Bb genotype associated with the highest median level (P=0.037). In a population-based sample of very old individuals (>85 years), the frequencies of the different VDR and COLIA 1 genotypes were similar among those with (n=64) and without (n=108) a history of hip fracture. Conclusion: The present data suggest that, in the Finnish population, the VDR and COLIA 1 genotypes do not determine the bone mass of early postmenopausal women or their bone turnover rate. The polymorphisms are not associated with risk of hip fractures in elderly people or with low-energy fractures in early postmenopausal women.

[Multiple genetic typing (vitamin D receptors and estrogens) in the assessment of the risk of fractures]

BACKGROUND

Several studies suggested that some vitamin D receptor (VDR) and estrogen receptor (ER) polymorphisms influence bone mass. However, others did not confirm these results. This study was undertaken to determine if the genotypes revealed by the combined analysis of VDR and ER polymorphisms are associated with clinically significant differences in peak bone mass and the risk of osteoporotic fractures.

PATIENTS AND METHODS

Restriction fragment length polymorphisms of VDR were determined with the enzymes Bsml, Apal, Taql, and Fokl. Enzymes Xbal and Pvull were used as polymorphic markers of the ER. The study group comprised 149 young control women (18-34 years), 66 postmenopausal controls, 99 women with hip fracture and 76 women with osteoporotic vertebral fractures. Bone mineral density (BMD) was measured by DEXA.

RESULTS

We did not find significant differences in lumbar spine or hip BMD among young women with different genotypes (determined with either single or multiple polymorphic markers). Likewise, there were no differences in the frequency distributions of VDR or ER alleles between control and fractured women. The study had a 77% power to detect a fracture odds ratio of 2 in case of genotypes present in at least 15% of the population.

CONCLUSIONS

These results suggest that the polymorphic markers used in this study do not have enough discriminant power to be clinically useful in the assessment of fracture risk.