| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Uitterlinden, André G, et al.
(författare)
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The association between common vitamin D receptor gene variations and osteoporosis : a participant-level meta-analysis
- 2006
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Ingår i: Annals of Internal Medicine. - 0003-4819. ; 145:4, s. 255-264
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Polymorphisms of the vitamin D receptor (VDR) gene have been implicated in the genetic regulation of bone mineral density (BMD). However, the clinical impact of these variants remains unclear.OBJECTIVE: To evaluate the relation between VDR polymorphisms, BMD, and fractures.DESIGN: Prospective multicenter large-scale association study.SETTING: The Genetic Markers for Osteoporosis consortium, involving 9 European research teams.PARTICIPANTS: 26,242 participants (18,405 women).MEASUREMENTS: Cdx2 promoter, FokI, BsmI, ApaI, and TaqI polymorphisms; BMD at the femoral neck and the lumbar spine by dual x-ray absorptiometry; and fractures.RESULTS: Comparisons of BMD at the lumbar spine and femoral neck showed nonsignificant differences less than 0.011 g/cm2 for any genotype with or without adjustments. A total of 6067 participants reported a history of fracture, and 2088 had vertebral fractures. For all VDR alleles, odds ratios for fractures were very close to 1.00 (range, 0.98 to 1.02) and collectively the 95% CIs ranged from 0.94 (lowest) to 1.07 (highest). For vertebral fractures, we observed a 9% (95% CI, 0% to 18%; P = 0.039) risk reduction for the Cdx2 A-allele (13% risk reduction in a dominant model).LIMITATIONS: The authors analyzed only selected VDR polymorphisms. Heterogeneity was detected in some analyses and may reflect some differences in collection of fracture data across cohorts. Not all fractures were related to osteoporosis.CONCLUSIONS: The FokI, BsmI, ApaI, and TaqI VDR polymorphisms are not associated with BMD or with fractures, but the Cdx2 polymorphism may be associated with risk for vertebral fractures.
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| 3. |
- van Meurs, Joyce B, et al.
(författare)
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Large-scale analysis of association between LRP5 and LRP6 variants and osteoporosis.
- 2008
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Ingår i: JAMA : the journal of the American Medical Association. - Chicago : American Medical Association (AMA). - 1538-3598 .- 0098-7484. ; 299:11, s. 1277-90
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene cause rare syndromes characterized by altered bone mineral density (BMD). More common LRP5 variants may affect osteoporosis risk in the general population. OBJECTIVE: To generate large-scale evidence on whether 2 common variants of LRP5 (Val667Met, Ala1330Val) and 1 variant of LRP6 (Ile1062Val) are associated with BMD and fracture risk. DESIGN AND SETTING: Prospective, multicenter, collaborative study of individual-level data on 37,534 individuals from 18 participating teams in Europe and North America. Data were collected between September 2004 and January 2007; analysis of the collected data was performed between February and May 2007. Bone mineral density was assessed by dual-energy x-ray absorptiometry. Fractures were identified via questionnaire, medical records, or radiographic documentation; incident fracture data were available for some cohorts, ascertained via routine surveillance methods, including radiographic examination for vertebral fractures. MAIN OUTCOME MEASURES: Bone mineral density of the lumbar spine and femoral neck; prevalence of all fractures and vertebral fractures. RESULTS: The Met667 allele of LRP5 was associated with reduced lumbar spine BMD (n = 25,052 [number of participants with available data]; 20-mg/cm2 lower BMD per Met667 allele copy; P = 3.3 x 10(-8)), as was the Val1330 allele (n = 24,812; 14-mg/cm2 lower BMD per Val1330 copy; P = 2.6 x 10(-9)). Similar effects were observed for femoral neck BMD, with a decrease of 11 mg/cm2 (P = 3.8 x 10(-5)) and 8 mg/cm2 (P = 5.0 x 10(-6)) for the Met667 and Val1330 alleles, respectively (n = 25 193). Findings were consistent across studies for both LRP5 alleles. Both alleles were associated with vertebral fractures (odds ratio [OR], 1.26; 95% confidence interval [CI], 1.08-1.47 for Met667 [2001 fractures among 20 488 individuals] and OR, 1.12; 95% CI, 1.01-1.24 for Val1330 [1988 fractures among 20,096 individuals]). Risk of all fractures was also increased with Met667 (OR, 1.14; 95% CI, 1.05-1.24 per allele [7876 fractures among 31,435 individuals)]) and Val1330 (OR, 1.06; 95% CI, 1.01-1.12 per allele [7802 fractures among 31 199 individuals]). Effects were similar when adjustments were made for age, weight, height, menopausal status, and use of hormone therapy. Fracture risks were partly attenuated by adjustment for BMD. Haplotype analysis indicated that Met667 and Val1330 variants both independently affected BMD. The LRP6 Ile1062Val polymorphism was not associated with any osteoporosis phenotype. All aforementioned associations except that between Val1330 and all fractures and vertebral fractures remained significant after multiple-comparison adjustments. CONCLUSIONS: Common LRP5 variants are consistently associated with BMD and fracture risk across different white populations. The magnitude of the effect is modest. LRP5 may be the first gene to reach a genome-wide significance level (a conservative level of significance [herein, unadjusted P < 10(-7)] that accounts for the many possible comparisons in the human genome) for a phenotype related to osteoporosis.
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| 4. |
- McGuigan, Fiona, et al.
(författare)
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Large-scale population-based study shows no association between common polymorphisms of the TGFB1 gene and BMD in women
- 2007
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 1523-4681 .- 0884-0431. ; 22:2, s. 195-202
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The gene encoding TGFBI is a strong functional candidate for genetic susceptibility to osteoporosis. Several polymorphisms have been identified in TGFB1, and previous work has suggested that allelic variants of TGFBI. may regulate BMD and susceptibility to osteoporotic fracture. Materials and Methods: We studied the relationship between common polymorphisms of TGFBI and several osteoporosis-related phenotypes including BMD at the lumbar spine and femoral neck, measured by DXA; bone loss over a 6-year period; biochemical markers of bone turnover (urinary free deoxypyridinoline and free pyridinoline/creatinine ratio and serum N-terminal propeptide of type 1 collagen), and fractures in a population-based study of 2975 women from the United Kingdom. Participants were genotyped for single nucleotide polymorphisms (SNPs) in the TGFB1 promoter(G-800A; rs1800468; C-509T; rs1800469), exon 1 (T29C; rs1982073 and G74C; rs1982073); and exon 5 (C788T; rs1800471) on PCR-generated fragments of genomic DNA. Haplotypes were constructed from genotype data using the PHASE software program, and genotypes and haplotypes were related to the phenotypes of interest using general linear model ANOVA, with correction for confounding factors including age, height, weight, menopausal status, hormone replacement therapy (HRT) use, physical activity score, and dietary calcium intake. Results: The polymorphisms were in strong linkage disequilibrium, and four common haplotypes accounted for > 95% of alleles at the locus. There was no association between individual SNPs and BMD, bone loss, or biochemical markers of bone turnover. Haplotype analysis showed a nominally significant association with femoral neck BMD (p = 0.042) and with incident osteoporotic fracture (p = 0.013), but these were not significant after correcting for multiple testing. Conclusions: Common polymorphic variants of the TGFBI gene did not influence BMD or bone loss in this population.
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| 5. |
- Pettersson, Ulrika, et al.
(författare)
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Polymorphisms of the CLCN7 gene are associated with BMD in women.
- 2005
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Ingår i: Journal of Bone and Mineral Research. - 0884-0431 .- 1523-4681. ; 20:11, s. 1960-7
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Tidskriftsartikel (refereegranskat)abstract
- UNLABELLED: Here we show that a common polymorphism causing a valine to methionine amino acid substitution at codon 418 (V418M) in the CLCN7 gene is associated with femoral neck BMD in women. Our study adds to accumulating evidence that shows that common allelic variants in monogenic bone disease genes often contribute to BMD regulation in normal subjects. INTRODUCTION: The CLCN7 gene is a strong candidate for regulation of BMD, because mutations in CLCN7 cause some forms of osteopetrosis, a disease characterized by impaired osteoclast function and increased BMD. In this study, we sought to determine whether common allelic variation within CLCN7 was associated with BMD in the normal population. MATERIALS AND METHODS: We conducted mutation screening of the exons and intron-exon boundaries in CLCN7 by DNA sequencing in 50 normal subjects. We conducted an association study between common polymorphisms in CLCN7 and haplotypes defined by these polymorphisms and BMD values at the lumbar spine and femoral neck in a population-based cohort study of 1077 Scottish women 45-55 years of age. RESULTS: We identified 24 polymorphisms, but most were rare and only 4 had allele frequencies of >5%. These were a conservative single nucleotide polymorphism (SNP) in exon 1 (rs3751884), a 50-bp tandem repeat polymorphism within intron 8, and two SNPs within exon 15 (rs12926089 and rs12926669), of which one (rs12926669) predicts an amino acid change from valine to methionine at codon 418 (V418M). The exon 15 SNPs were in strong linkage disequilibrium and were both associated with femoral neck BMD (p = 0.001-0.003). None of the other polymorphisms were associated with BMD, and long-range haplotypes showed a much weaker association with BMD than the exon 15 SNPs. The V418M polymorphism was an independent predictor of femoral neck BMD on multiple regression analysis accounting for 1% of the variance in BMD at this site. CONCLUSIONS: Our study indicates that the V418M polymorphism of CLCN7 contributes to the genetic regulation of femoral neck BMD in women and adds to accumulating evidence that indicates that subtle polymorphic variation in genes that cause monogenic bone diseases also contribute to regulation of BMD in normal subjects.
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| 6. |
- Stewart, Tracy L, et al.
(författare)
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Haplotypes defined by promoter and intron 1 polymorphisms of the COLIA1 gene regulate bone mineral density in women
- 2006
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 91:9, s. 3575-3583
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: The COLIA1 gene is a strong candidate for susceptibility to osteoporosis. The causal genetic variants are currently unclear, but the most likely are functional polymorphisms in the promoter and intron 1 of COLIA1. OBJECTIVE: The objective of the study was to determine whether promoter and intron 1 polymorphisms of COLIA1 or haplotypes defined by these polymorphisms regulate bone mineral density (BMD) in women. DESIGN: This was a population-based association study involving 3270 women from the United Kingdom who took part in a regional osteoporosis screening program. MAIN OUTCOME MEASURES: BMD at the lumbar spine (LS-BMD) and femoral neck (FN-BMD) was measured on two occasions approximately 6 yr apart, in relation to polymorphisms and haplotypes defined by polymorphisms within the COLIA1 intron 1 (+1245G/T; rs1800012) and promoter (-1997G/T; rs1107946; -1663IndelT; rs2412298). RESULTS: The polymorphisms were in strong linkage disequilibrium, and three haplotypes accounted for more than 95% of alleles at the COLIA1 locus. The individual polymorphisms were associated with BMD, but the most consistent associations were with haplotypes defined by all three polymorphisms. Homozygote carriers of haplotype 2 (-1997G/-1663delT/+1245T) had reduced BMD at baseline (P = 0.007 for LS-BMD; P = 0.008 for FN-BMD), whereas homozygotes for haplotype 3 (-1997T/-1663insT/+1245G) had increased BMD (P = 0.007 for LS-BMD). Similar associations were observed at follow-up for haplotype 3, but the association with haplotype 2 was weaker due to increased uptake of hormone replacement therapy in homozygotes for this haplotype. CONCLUSIONS: Two haplotypes defined by polymorphisms in the 5' flank of the COLIA1 regulate BMD in a bidirectional manner in women.
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