| 1. |
- Johannesdottir, Fjola, et al.
(författare)
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Distribution of cortical bone in the femoral neck and hip fracture: A prospective case-control analysis of 143 incident hip fractures; the AGES-REYKJAVIK Study
- 2011
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Ingår i: Bone. - : Elsevier BV. - 1873-2763 .- 8756-3282. ; 48:6, s. 1268-1276
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Tidskriftsartikel (refereegranskat)abstract
- In this prospective nested case-control study we analyzed the circumferential differences in estimated cortical thickness (Est CTh) of the mid femoral neck as a risk factor for osteoporotic hip fractures in elderly women and men. Segmental QCT analysis of the mid femoral neck was applied to assess cortical thickness in anatomical quadrants. The superior region of the femoral neck was a stronger predictor for hip fracture than the inferior region, particularly in men. There were significant gender differences in Est CTh measurements in the control group but not in the case group. In multivariable analysis for risk of femoral neck (FN) fracture, Est CTh in the supero-anterior (SA) quadrant was significant in both women and men, and remained a significant predictor after adjustment for FN areal BMD (aBMD, dimensions g/cm(2), DXA-like), (p = 0.05 and p<0.0001, respectively). In conclusion, Est CTh in the SA quadrant best discriminated cases (n = 143) from controls (n = 298), especially in men. Cortical thinning superiorly in the hip might be of importance in determining resistance to fracture. (C) 2011 Elsevier Inc. All rights reserved.
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| 2. |
- Johannesdottir, Fjola, et al.
(författare)
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Mid-Thigh Cortical Bone Structural Parameters, Muscle Mass and Strength, and Association with Lower Limb Fractures in Older Men and Women (AGES-Reykjavik Study)
- 2012
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 1432-0827 .- 0171-967X. ; 90:5, s. 354-364
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Tidskriftsartikel (refereegranskat)abstract
- In a cross-sectional study we investigated the relationship between muscle and bone parameters in the mid-thigh in older people using data from a single axial computed tomographic section through the mid-thigh. Additionally, we studied the association of these variables with incident low-trauma lower limb fractures. A total of 3,762 older individuals (1,838 men and 1,924 women), aged 66-96 years, participants in the AGES-Reykjavik study, were studied. The total cross-sectional muscular area and knee extensor strength declined with age similarly in both sexes. Muscle parameters correlated most strongly with cortical area and total shaft area (adjusted for age, height, and weight) but explained < 10 % of variability in those bone parameters. The increment in medullary area (MA) and buckling ratio (BR) with age was almost fourfold greater in women than men. The association between MA and muscle parameters was nonsignificant. During a median follow-up of 5.3 years, 113 women and 66 men sustained incident lower limb fractures. Small muscular area, low knee extensor strength, large MA, low cortical thickness, and high BR were significantly associated with fractures in both sexes. Our results show that bone and muscle loss proceed at different rates and with different gender patterns.
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| 3. |
- Rianon, Nahid J., et al.
(författare)
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Fracture Risk Assessment in Older Adults Using a Combination of Selected Quantitative Computed Tomography Bone Measures: A Subanalysis of the Age, Gene/Environment Susceptibility-Reykjavik Study
- 2014
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Ingår i: Journal of Clinical Densitometry. - : Elsevier BV. - 1094-6950. ; 17:1, s. 25-31
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Tidskriftsartikel (refereegranskat)abstract
- Bone mineral density (BMD) and geometric bone measures are individually associated with prevalent osteoporotic fractures. Whether an aggregate of these measures would better associate with fractures has not been examined. We examined relationships between self-reported fractures and selected bone measures acquired by quantitative computerized tomography (QCT), a composite bone score, and QCT-acquired dual-energy X-ray absorptiometry-like total femur BMD in 2110 men and 2682 women in the Age, Gene/Environment Susceptibility-Reykjavik Study. The combined bone score was generated by summing gender-specific Z-scores for 4 QCT measures: vertebral trabecular BMD, femur neck cortical thickness, femur neck trabecular BMD, and femur neck minimal cross-sectional area. Except for the latter measure, lower scores for QCT measures, singly and combined, showed positive (p < 0.05) associations with fractures. Results remained the same in stratified models for participants not taking bone-promoting medication. In women on bone-promoting medication, greater femur neck cortical thickness and trabecular BMD were significantly associated with fracture status. However, the association between fracture and combined bone score was not stronger than the associations between fracture and individual measures or total femur BMD. Thus, the selected measures did not all similarly associate with fracture status and did not appear to have an additive effect on fracture status.
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| 4. |
- Bjornsdottir, Erla, et al.
(författare)
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Symptoms of Insomnia among Patients with Obstructive Sleep Apnea Before and After Two Years of Positive Airway Pressure Treatment
- 2013
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Ingår i: Sleep. - : Oxford University Press (OUP). - 0161-8105 .- 1550-9109. ; 36:12, s. 1901-1909
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Tidskriftsartikel (refereegranskat)abstract
- Study Objectives: To assess the changes of insomnia symptoms among patients with obstructive sleep apnea (OSA) from starting treatment with positive airway pressure (PAP) to a 2-y follow-up. Design: Longitudinal cohort study. Setting: Landspitali-The National University Hospital of Iceland. Participants: There were 705 adults with OSA who were assessed prior to and 2 y after starting PAP treatment. Intervention: PAP treatment for OSA. Measurements and Results: All patients underwent a medical examination along with a type 3 sleep study and answered questionnaires on health and sleep before and 2 y after starting PAP treatment. The change in prevalence of insomnia symptoms by subtype was assessed by questionnaire and compared between individuals who were using or not using PAP at follow-up. Symptoms of middle insomnia were most common at baseline and improved significantly among patients using PAP (from 59.4% to 30.7%, P < 0.001). Symptoms of initial insomnia tended to persist regardless of PAP treatment, and symptoms of late insomnia were more likely to improve among patients not using PAP. Patients with symptoms of initial and late insomnia at baseline were less likely to adhere to PAP (odds ratio [OR] 0.56, P = 0.007, and OR 0.53, P < 0.001, respectively). Conclusion: Positive airway pressure treatment significantly reduced symptoms of middle insomnia. Symptoms of initial and late insomnia, however, tended to persist regardless of positive airway pressure treatment and had a negative effect on adherence. Targeted treatment for insomnia may be beneficial for patients with obstructive sleep apnea comorbid with insomnia and has the potential to positively affect adherence to positive airway pressure.
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| 5. |
- Bjornsdottir, Gudlaug, et al.
(författare)
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Longitudinal changes in size and composition of carotid artery plaques using ultrasound: Adaptation and validation of methods (inter-and intraobserver variability)
- 2014
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Ingår i: Journal for Vascular Ultrasound. - : SAGE Publications. - 1544-3175 .- 1544-3167. ; 38:4, s. 198-208
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Tidskriftsartikel (refereegranskat)abstract
- Introduction.—B-mode ultrasonography of the carotid arteries enables quantitative measurements of atherosclerotic plaque area and composition assessed as grayscale median (GSM). The purpose of this study was to set up a standardized ultrasound protocol to measure longitudinal changes in plaque area and composition and to determine the intra-and interobserver variability of the measurements in a longitudinal population based study, the Age Gene/ Environment Susceptibility Reykjavik study. Method.—A total of 219 participants from the Age Gene/Environment Susceptibility Reykjavik study (76 ± 6 years old, 36% males) underwent 2-dimensional, B-mode ultrasound examination of the carotid arteries approximately 5 years apart for a longitudinal assessment of plaque area and composition. Standardized protocol was used to acquire comparable images from both visits. Ultrasound was performed bilaterally on the common carotid artery, internal carotid artery, and bifurcation. An image analysis program was modified and adapted for a longitudinal assessment of plaque area and plaque composition by GSM. Twenty-five subjects were selected from the group of 219 for intra-and interobserver variability assessment. Results.—Intraobserver variability for plaque area ranged from 12.10 to 18.63% and 0.89 to 0.96 for coefficient of variation and correlation (r), respectively, for plaque GSM ranged from 7.77 to 8.04% and 0.86 to 0.90. Interobserver variability for plaque area was 23.29% and 0.81 and 8.55% and 0.87 for plaque GSM. Conclusion.—The results from this study show that ultrasound can be used consistently for assessment of changes in plaque area and GSM over time. This can be achieved by proper training of ultrasound sonographers and by applying and following strict image acquisition and image analysis protocols.
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| 6. |
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| 7. |
- Ikram, M. Arfan, et al.
(författare)
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Common variants at 6q22 and 17q21 are associated with intracranial volume
- 2012
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:5, s. 539-544
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Tidskriftsartikel (refereegranskat)abstract
- During aging, intracranial volume remains unchanged and represents maximally attained brain size, while various interacting biological phenomena lead to brain volume loss. Consequently, intracranial volume and brain volume in late life reflect different genetic influences. Our genome-wide association study (GWAS) in 8,175 community-dwelling elderly persons did not reveal any associations at genome-wide significance (P < 5 x 10(-8)) for brain volume. In contrast, intracranial volume was significantly associated with two loci: rs4273712 (P = 3.4 x 10(-11)), a known height-associated locus on chromosome 6q22, and rs9915547 (P = 1.5 x 10(-12)), localized to the inversion on chromosome 17q21. We replicated the associations of these loci with intracranial volume in a separate sample of 1,752 elderly persons (P = 1.1 x 10(-3) for 6q22 and 1.2 x 10(-3) for 17q21). Furthermore, we also found suggestive associations of the 17q21 locus with head circumference in 10,768 children (mean age of 14.5 months). Our data identify two loci associated with head size, with the inversion at 17q21 also likely to be involved in attaining maximal brain size.
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| 8. |
- Malhotra, Rajeev, et al.
(författare)
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HDAC9 is implicated in atherosclerotic aortic calcification and affects vascular smooth muscle cell phenotype
- 2019
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 51:11, s. 1580-
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Tidskriftsartikel (refereegranskat)abstract
- Aortic calcification is an important independent predictor of future cardiovascular events. We performed a genome-wide association meta-analysis to determine SNPs associated with the extent of abdominal aortic calcification (n = 9,417) or descending thoracic aortic calcification (n = 8,422). Two genetic loci, HDAC9 and RAP1GAP, were associated with abdominal aortic calcification at a genome-wide level (P < 5.0 × 10−8). No SNPs were associated with thoracic aortic calcification at the genome-wide threshold. Increased expression of HDAC9 in human aortic smooth muscle cells promoted calcification and reduced contractility, while inhibition of HDAC9 in human aortic smooth muscle cells inhibited calcification and enhanced cell contractility. In matrix Gla protein–deficient mice, a model of human vascular calcification, mice lacking HDAC9 had a 40% reduction in aortic calcification and improved survival. This translational genomic study identifies the first genetic risk locus associated with calcification of the abdominal aorta and describes a previously unknown role for HDAC9 in the development of vascular calcification.
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| 9. |
- Qiu, Chengxuan, et al.
(författare)
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Cerebral microbleeds and age-related macular degeneration : the AGES-Reykjavik Study
- 2012
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 33:12, s. 2935-2937
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Tidskriftsartikel (refereegranskat)abstract
- We test the hypothesis that cerebral microbleeds (CMB) and age-related macular degeneration (AMD), both linked to amyloid-beta deposition, are correlated. This study includes 4205 participants (mean age 76.2; 57.8% women) in the Age, Gene/Environment Susceptibility (AGES)Reykjavik Study (2002-2006). CMB were assessed from magnetic resonance images, and AMD was assessed using digital retinal images. Data were analyzed with multinomial logistic models controlling for major confounders. Evidence of CMB was detected in 476 persons (272 with strict lobar CMB and 204 with nonlobar CMB). AMD was detected in 1098 persons (869 with early AMD, 140 with exudative AMD, and 89 with pure geographic atrophy). Early and exudative AMD were not associated with CMB. The adjusted odds ratio of pure geographic atrophy was 1.62 (95% confidence interval 0.93-2.82, p = 0.089) for having any CMB, 1.43 (0.66-3.06, p = 0.363) for strict lobar CMB, and 1.85 (0.89-3.87, p = 0.100) for nonlobar CMB. This study provides no evidence that amyloid deposits in the brain and AMD are correlated. However, the suggestive association of geographic atrophy with CMB warrants further investigation.
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| 10. |
- Qiu, Chengxuan, et al.
(författare)
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Diabetes, Markers of Brain Pathology and Cognitive Function : The Age, Gene/Environment Susceptibility-Reykjavik Study
- 2014
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Ingår i: Annals of Neurology. - : Wiley. - 0364-5134 .- 1531-8249. ; 75:1, s. 138-146
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Tidskriftsartikel (refereegranskat)abstract
- Objective: We investigated whether, and the extent to which, vascular and degenerative lesions in the brain mediate the association of diabetes with poor cognitive performance. Methods: This cross-sectional study included 4,206 participants (age>65 years; 57.8% women) of the Age, Gene/Environment Susceptibility-Reykjavik Study. Data were collected through interview, clinical examination, psychological testing, and laboratory tests. The composite scores on memory, information-processing speed, and executive function were derived from a cognitive test battery. Markers of cerebral macrovascular (cortical infarcts), microvascular (subcortical infarcts, cerebral microbleeds, and higher white matter lesion volume), and neurodegenerative (lower gray matter, normal white matter, and total brain tissue volumes) processes were assessed on magnetic resonance images. Mediation models were employed to test the mediating effect of brain lesions on the association of diabetes with cognitive performance controlling for potential confounders. Results: There were 462 (11.0%) persons with diabetes. Diabetes was significantly associated with lower scores on processing speed and executive function, but not with memory function. Diabetes was significantly associated with all markers of brain pathology. All of these markers were significantly associated with lower scores on memory, processing speed, and executive function. Formal mediation tests suggested that markers of cerebrovascular and degenerative pathology significantly mediated the associations of diabetes with processing speed and executive function. Interpretation: Diabetes is associated with poor performance on cognitive tests of information-processing speed and executive function. The association is largely mediated by markers of both neurodegeneration and cerebrovascular disease. Older people with diabetes should be monitored for cognitive problems and brain lesions.
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