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

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 BsmI polymorphism and osteoporosis risk in post-menopausal women

INTRODUCTION

Many studies have suggested that the vitamin D receptor polymorphism BsmI might be associated with the risk of osteoporosis development in post-menopausal women. However, the results have been inconsistent. The aim of this meta-analysis was to derive a more precise evaluation of the relationship.

MATERIAL AND METHODS

Published literature from PubMed, EMBASE and the CNKI database was searched. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of any association.

RESULTS

Ten case-control studies were included with a total of 1,403 osteoporosis cases and 2,144 healthy controls. In the overall analysis, no significant association was found between BsmI polymorphism and osteoporosis risk (BB vs. bb: OR = 0.76, 95% CI = 0.39-1.48; BB vs. Bb: OR = 0.90, 95% CI = 0.71-1.15; dominant model: OR = 1.20, 95% CI = 0.74-1.93; recessive model: OR = 0.83, 95% CI = 0.53-1.30). In the subgroup analysis by ethnicity, the results showed similar result that BsmI polymorphism m had no association with osteoporosis.

CONCLUSIONS

Results from the current meta-analysis suggest that vitamin D receptor BsmI polymorphism may not be a risk factor for osteoporosis in post-menopausal women.

Combined effects of collagen type I alpha1 (COL1A1) Sp1 polymorphism and osteoporosis risk factors on bone mineral density in Turkish postmenopausal women

Identification of risk factors for osteoporosis has been essential for understanding the development of osteoporosis. The collagen type I alpha1 (COL1A1) gene is suggested to be implicated in reduced bone mineral density (BMD) in osteoporosis. In the present study, the investigation of the effects of Sp1 polymorphic variants of COL1A1 gene on BMD values, and the determination of the association between COL1A1 Sp1 gene variants and osteoporosis risk factors in the context of gene-environment interaction in Turkish postmenopausal women were aimed. For the detection of COL1A1 Sp1 polymorphism, PCR-RFLP techniques have been used. BMD for lumbar spine (L1-L4) and hip (femoral neck and total hip) was measured by DXA. This study was carried out using a sample of 254 postmenopausal women. We observed a trend decrease in BMD values in the subjects with "ss" genotype having lower BMD of lumbar spine, femoral neck and total hip than those with "SS" and "Ss" genotype, however the differences did not reach statistical significance (P>0.05). We also found that the frequencies of the BMD under mean values at the femoral neck (57.5%) and total hip (76.2%) increased considerably in the subjects carrying "Ss/ss" genotypes in combination of having family history of osteoporosis (61.5% for femoral neck) and smoking history (90.0% for total hip). This population-based study indicates that COL1A1 Sp1 polymorphism may contribute to the development of osteoporosis in combination of osteoporosis risk factors in Turkish postmenopausal women.

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.

Beyond the definitions of the phenotypic complications of sickle cell disease: an update on management

The sickle hemoglobin is an abnormal hemoglobin due to point mutation (GAG → GTG) in exon 1 of the β globin gene resulting in the substitution of glutamic acid by valine at position 6 of the β globin polypeptide chain. Although the molecular lesion is a single-point mutation, the sickle gene is pleiotropic in nature causing multiple phenotypic expressions that constitute the various complications of sickle cell disease in general and sickle cell anemia in particular. The disease itself is chronic in nature but many of its complications are acute such as the recurrent acute painful crises (its hallmark), acute chest syndrome, and priapism. These complications vary considerably among patients, in the same patient with time, among countries and with age and sex. To date, there is no well-established consensus among providers on the management of the complications of sickle cell disease due in part to lack of evidence and in part to differences in the experience of providers. It is the aim of this paper to review available current approaches to manage the major complications of sickle cell disease. We hope that this will establish another preliminary forum among providers that may eventually lead the way to better outcomes.

Polymorphisms in the 5' flank of COL1A1 gene and osteoporosis: meta-analysis of published studies

A meta-analysis of studies was conducted involving 24,511 participants with 7,864 fractures in which polymorphisms in the 5' flank of COL1A1 (rs1107946, rs2412298, and rs1800012) were related to osteoporosis phenotypes. Polymorphisms of all three sites were associated with BMD, and rs1800012 was associated with fracture but effect sizes were modest.

INTRODUCTION AND HYPOTHESIS

Polymorphisms in the 5' flank of COL1A1 gene have been implicated as genetic markers for susceptibility to osteoporosis, but previous studies have yielded conflicting results.

METHODS

We conducted a meta-analysis of 32 studies including 24,511 participants and 7,864 fractures in which alleles at the -1997G/T (rs1107946), -1663in/delT (rs2412298), and Sp1 binding site polymorphisms (rs1800012) of COL1A1 had been related to bone mineral density (BMD) or fracture.

RESULTS

For the Sp1 polymorphism, BMD values in TT homozygotes were 0.13 units [95% CI, 0.03 to 0.24] lower at the spine (p = 0.01) and 0.16 units [0.10 to 0.23] lower at the hip (p = 1 x 10⁻⁶) than GG homozygotes. Clinical fractures were 1.31-fold [1.04-1.65] increased in TT homozygotes (p = 0.02) and vertebral fractures were 1.34-fold [1.01-1.77] increased (p = 0.04). We also observed associations between spine BMD and allelic variants at the -1997G/T (p = 0.05) and the -1663indelT (p = 0.009) sites. We found no association between alleles at the -1997G/T or -1663indelT sites and fracture but power was limited.

CONCLUSIONS

The COL1A1 Sp1 polymorphism is associated with a modest reduction in BMD and an increased risk of fracture, although we cannot fully exclude the possibility that the results may have been influenced by publication bias. Further studies are required to fully evaluate the contribution of the -1997G/T and -1663in/delT sites to these phenotypes and to determine if they interact with the Sp1 polymorphism to regulate susceptibility to osteoporosis.

Synopsis and meta-analysis of genetic association studies in osteoporosis for the focal adhesion family genes: the CUMAGAS-OSTEOporosis information system

BACKGROUND

Focal adhesion (FA) family genes have been studied as candidate genes for osteoporosis, but the results of genetic association studies (GASs) are controversial. To clarify these data, a systematic assessment of GASs for FA genes in osteoporosis was conducted.

METHODS

We developed Cumulative Meta-Analysis of GAS-OSTEOporosis (CUMAGAS-OSTEOporosis), a web-based information system that allows the retrieval, analysis and meta-analysis (for allele contrast, recessive, dominant, additive and codominant models) of data from GASs on osteoporosis with the capability of update. GASs were identified by searching the PubMed and HuGE PubLit databases.

RESULTS

Data from 72 studies involving 13 variants of 6 genes were analyzed and catalogued in CUMAGAS-OSTEOporosis. Twenty-two studies produced significant associations with osteoporosis risk under any genetic model. All studies were underpowered (<50%). In four studies, the controls deviated from the Hardy-Weinberg equilibrium. Eight variants were chosen for meta-analysis, and significance was shown for the variants collagen, type I, α1 (COL1A1) G2046T (all genetic models), COL1A1 G-1997T (allele contrast and dominant model) and integrin β-chain β3 (ITGB3) T176C (recessive and additive models). In COL1A1 G2046T, subgroup analysis has shown significant associations for Caucasians, adults, females, males and postmenopausal women. A differential magnitude of effect in large versus small studies (that is, indication of publication bias) was detected for the variant COL1A1 G2046T.

CONCLUSION

There is evidence of an implication of FA family genes in osteoporosis. CUMAGAS-OSTEOporosis could be a useful tool for current genomic epidemiology research in the field of osteoporosis.

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.

Association of Collagen Type I α1 (COLIA1) Sp1 Polymorphism with Osteoporotic Fracture in Caucasian Post-menopausal Women: a Meta-analysis

This study was designed to summarize quantitatively the evidence for a relationship between collagen type I α1 (COLIA1) Sp1 polymorphism and osteoporotic fracture risk in Caucasian post-menopausal women. This meta-analysis included 16 studies, which analysed 2294 patients with fractures and 10285 controls. The combined results showed that there was a significant difference in genotype distribution (SS odds ratio [OR] 0.72; Ss OR 1.18; ss OR 1.97) between patients with fractures and controls. When stratifying by the fracture site, it was found that: (i) patients with vertebral fractures had a significantly higher frequency of the Ss genotype and a lower frequency of the SS genotype than controls; and (ii) patients with non-vertebral fractures had a significantly higher frequency of the ss genotype and a lower frequency of the SS genotype than controls. This meta-analysis suggests that the COLIA1 Sp1 polymorphism may be associated with osteoporotic fracture in Caucasian post-menopausal women.

Searching for genes underlying susceptibility to osteoporotic fracture: current progress and future prospect

INTRODUCTION

Osteoporotic fracture (OF) is a public health problem. It is a common practice in the genetics of osteoporosis that bone mineral density (BMD) was studied as a major surrogate phenotype in gene search for risk of OF (ROF) because of their high phenotypic correlation. However, some studies indicate that the genetic correlation between BMD and ROF is very low. This implies that most genes found important for BMD may not be relevant to ROF. Ideally, employing OF per se as a direct study phenotype can directly find the relevant genes underlying ROF.

EVIDENCE

Here, we summarized some evidence supporting ROF under moderate genetic control, and the current progress of molecular genetic studies employing OF as the direct study phenotype, then give our consideration on the future prospects in the genetics of ROF.

Collagen type 1 (COL1A1) Sp1 binding site polymorphism is associated with osteoporotic fractures but not with bone density in post-menopausal women from the Canary Islands: a preliminary study

BACKGROUND AND AIMS

An association between the polymorphism for transcription factor Sp1 in the gene COL1A1 and low bone density (BMD) and osteoporotic fractures has been described but not confirmed for all races and ages. The aim of this preliminary work was to ascertain whether this association is present in women from the Canary Islands.

METHODS

Polymerase chain reaction RFLP was used to determine COL1A1 polymorphism Sp1 in 199 consecutive outpatient post-menopausal Caucasian women from the Canary Islands, aged 50-70 years. BMD was measured at lumbar spine and hip by DXA and at third lumbar vertebrae by QCT. Prevalent vertebral fractures were recorded on standard lateral X-ray film. Non-vertebral osteoporotic fractures were registered by medical record and self-reported history. Biochemical markers (serum osteocalcin, tartrate-resistant acid phosphatase), blood calcium and phosphate were also assessed.

RESULTS

Distribution genotypes were 113 (50.8%) GG homozygotes, 73 (36.7%) Ss heterozygotes and 7 (3.5%) TT homozygotes. All patients with osteoporotic fractures carried the GG allele more frequently than TT homozygotic women. The odds ratio was 3.01 (95% CI 1.6-5.7) for prevalent vertebral fractures (n=62) and 2.33 (95% CI 1.2-4.4) for all osteoporotic fractures (n=65) for the T-carrying allele vs TT homozygotic women. There was no difference in BMD measured by DXA or QCT, nor in bone markers, blood calcium or phosphate.

CONCLUSIONS

This preliminary study confirmed that the presence of at least one copy of the T allele is associated with osteoporotic fractures, but not with low BMD, in women from the Canary Islands.

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.

COL1A1 Sp1 polymorphism associates with bone density in early puberty

Optimal acquisition of bone mass in puberty is a key determinant of the lifetime risk of osteoporosis and has a strong genetic basis. We investigated the relationship between the COL1A1 Sp1 polymorphism and BMD in early puberty, and how the genotypes relate to bone size and geometry as well as bone turnover and material properties in 247 10- to 13-year-old girls. Bone properties were measured using DXA, pQCT, and ultrasound. Also, serum P1NP, OC, B-ALP, and TRACP 5b were assessed. Our results showed that girls with the TT genotype had significantly lower BMC and BMD of the total body, lumbar spine, and proximal femur, as well as BUA at the calcaneus, than those with the GT and GG genotype. They also had significantly lower B-ALP, as well as P1NP/TRACP 5b and (OC + B-ALP)/TRACP 5b, compared to the others. These findings indicate that the COL1A1 polymorphism is associated with low bone properties in early puberty and suggest a possible physiological effect on collagen metabolism and bone turnover. This information may contribute to the identification of children at risk for suboptimal acquisition of peak bone mass and may ultimately be of value in the planning of early preventive strategies for osteoporosis.

Association between bone mineral density and polymorphisms of the VDR, ERalpha, COL1A1 and CTR genes in Spanish postmenopausal women

Bone mineral density (BMD), the major determinant of osteoporotic fracture risk, has a strong genetic component, and several candidate gene polymorphisms have been implicated in the regulation of this process. In view of the reported associations between the BMD and polymorphisms in the collagen type I alpha 1 gene (COL1A1), vitamin D receptor (VDR), estrogen receptor (ER)alpha and calcitonin receptor (CTR) genes, an association study was performed between VDR, COL1A1, CTR and ER genotypes and lumbar spine, femoral neck and Ward's triangle BMD in postmenopausal Spanish women. We statistically controlled for many confounding factors, such as height, weight, age, years since menopause, use of hormone replacement therapy (HRT), tobacco consumption, use of oral contraceptives, calcium dietary intake or exercise practice. No association between COL1A1 or ER genotypes and BMD was detected. However, we described a statistically significant association between a personal history of fractures and COL1A1 genotype. The ss genotype was found to be over-represented between those women who had a personal history of fractures. The analyses of the VDR polymorphisms showed that FF subjects reached the highest values of BMD at the three measured sites, whereas Ff individuals had an intermediate BMD and ff women had the lowest values. However, the VDR-BsmI gene polymorphism was not found to be associated with adjusted BMD. For the CTR polymorphisms, our study showed that women with the aa genotype had a lower adjusted BMD at the femoral neck. In conclusion, in our postmenopausal Spanish women cohort we found a statistically significant association beteween the VDR and CTR gene polymorphisms and the BMD. However, we did not find any association between the ER and COL1A1 gene and the BMD. The COL1A1 gene was found to be associated with the prevalence of osteoporotic fractures. Of all the studied gene polymorphisms, the FokI VDR gene polymorphism seems to be the strongest BMD genetic determinant of postmenopausal Spanish women.

Association of the collagen type 1 (COL1A 1) Sp1 binding site polymorphism to femoral neck bone mineral density and wrist fracture in 1044 elderly Swedish women

Identification of risk factors for osteoporosis has been essential for understanding the development of osteoporosis and related fragility fractures. A polymorphism of the binding site for the transcription factor Sp1 of the collagen I alpha 1 gene (COLIA1) has shown an association to bone mass and fracture, but the findings have not been consistent, which may be related to population differences. The Sp1 polymorphism was determined in 1044 women, all 75 years old, participating in the population-based Osteoporosis Prospective Risk Assessment study in Malmö (OPRA). Bone mineral density, heel ultrasound and all previous fractures were registered. BMD was 2.7% lower in the femoral neck in women carrying at least one copy of the "s" allele ( P = 0.027). There was no difference in bone mass at any other site, weight, BMI or age at menopause. Women with a prevalent wrist fracture (n = 181) had an increased presence of the "s" allele. The odds ratio for prevalent wrist fracture was 2.73 (95% CI 1.1-6.8) for the ss homozygotes and 1.4 (95% CI 1.0-2.0) for the Ss heterozygotes when compared with the SS homozygotes. In conclusion, in this large and homogeneous cohort of 75-year-old Swedish women, there was an association among the Sp1 COLIA1 polymorphism, bone mass, and fracture. The presence of at least one copy of the "s" allele was associated with lower femoral neck BMD and previous wrist fracture and in addition, it was related to an increased risk for wrist fracture.

Meta-analysis of COL1A1 Sp1 polymorphism in relation to bone mineral density and osteoporotic fracture

Genetic factors play an important role in the pathogenesis of osteoporosis and several candidate gene polymorphisms have been implicated in the regulation of this process. One of the most widely studied is the Sp1 binding site polymorphism in the COL1A1 gene. This polymorphism has been associated with BMD and osteoporotic fracture in several studies, but the data from different studies have been conflicting. Here we have attempted to clarify the association between COL1A1 Sp1 alleles, BMD, and osteoporotic fracture by conducting a meta-analysis of 26 published studies including 7849 participants. Under a fixed effects model, BMD values at the lumbar spine (6800 subjects) were significantly lower in the "Ss" genotype group when compared with "SS" homozygotes (standardized mean difference = 0.131 [95% CI, 0.06,0.16], P = 0.00005) but the difference was not significant for the "ss" comparison (0.09 [-0.03,0.21], P = 0.13). At the femoral neck (6750 subjects) BMD values were lower in the "Ss" genotype (0.14 [0.08,0.19], P < 0.00001) and lower still in the "ss" genotype group (0.19 [0.07,0.31], P = 0.001). Similar results were found when the data were analyzed under a random effects model. Analysis of fracture data (6961 subjects) showed an increased odds ratio for any fracture in "Ss" subjects (1.26 [95% CI 1.09,1.46], P = 0.002) and an even greater increase in "ss" subjects (1.78 [1.30,2.43], P = 0.0003). Subgroup analysis showed that increased risk was largely attributable to vertebral fracture where the odds ratio was 1.37 [1.15,1.64] for "Ss" (P = 0.0004) and 2.48 [1.69,3.65] for "ss" (P < 0.00001). The risk of nonvertebral fracture was not increased in relation to the COL1A1 genotype, although power to detect an effect was limited by the fact that fewer studies had analyzed nonvertebral fracture. We conclude that the COL1A1 Sp1 alleles are associated with a modest reduction in BMD and a significant increase in risk of osteoporotic fracture, particularly vertebral fracture.