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Dive into the research topics where Brynjolfur Jonsson is active.

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Featured researches published by Brynjolfur Jonsson.


Calcified Tissue International | 2005

Long-Term Morbidity and Mortality After a Clinically Diagnosed Vertebral Fracture in the Elderly-a 12- and 22-Year Follow-up of 257 Patients.

Ralph Hasserius; M K Karlsson; Brynjolfur Jonsson; Inga Redlund-Johnell; Olof Johnell

The objective of this study was to analyze the long-term morbidity and mortality in patients with a clinically diagnosed vertebral fracture. Seventy men with a mean age of 70 years (range 50–91 years) and 187 women with a mean age of 72 years (range 50–96 years) were radiographically diagnosed as having a vertebral fracture in the thoracic or lumbar spine at the Malmö University Hospital (Sweden) during 1979. At the time of a follow-up examination 12 years later, 56 of the 76 patients who were still alive participated in an investigation that evaluated back pain and subjective health status by a questionnaire. Forty-four of these subjects also participated in a further radiologic examination of the spine. Serving as controls were age- and gender-matched subjects from the Malmö cohort of the European Vertebral Osteoporosis Study (EVOS). A mortality analysis was also conducted, covering 22 years following the baseline fracture. There were more female patients, who, in comparison with the controls, 12 years after the diagnosis, had had back pain during the year preceding the follow-up (72% vs 33%, P < 0.001), had current back pain (42% vs. 19%, P = 0.006), and had a subjectively impaired health status (44% vs. 17%, P < 0.001). The corresponding differences in men reached only a borderline significance, for both back pain during the year preceding the follow-up (60% vs. 28%, P = 0.07) and current back pain (40% vs. 15%, P = 0.09), whereas there was no difference in subjective health status. The incidence of new vertebral fractures in individuals with a clinically diagnosed vertebral fracture during the following 12 years was in men 25 per 1,000 person-years and in women 49 per 1000 person-years. There were more women with a new vertebral fracture at the 12-year follow-up examination who, in comparison with women without a new fracture, had had back pain during the year preceding the follow-up examination (90% vs. 50%, age-adjusted P = 0.02) and had current back pain (65% vs. 21%, age-adjusted P = 0.03). Women with a new vertebral fracture at the 12-year follow-up examination had a higher subsequent mortality rate in the next 10 years [age-adjusted hazard ratio 2.8 (95% CI 1.0–7.9)] as compared with women without. The mortality rate during the 22 years following the diagnosis among the male patients was 111.7 per 1,000 person-years as compared with 73.4 per 1,000 person-years among the male population at risk. The mortality rate among the female patients was 95.1 per 1,000 person-years as compared with 62.0 per 1,000 person-years among the female population at risk. We conclude that a clinically diagnosed thoracic or lumbar vertebral fracture in the elderly can be regarded as a risk factor for subsequent, long-term morbidity, especially in women, and for mortality in both genders.


Bone | 2011

Male–female differences in the association between incident hip fracture and proximal femoral strength: A finite element analysis study

Joyce H. Keyak; Sigurdur Sigurdsson; G. Karlsdottir; Diana Oskarsdottir; A. Sigmarsdottir; S. Zhao; John Kornak; T. B. Harris; Gunnar Sigurdsson; Brynjolfur Jonsson; Kristin Siggeirsdottir; Gudny Eiriksdottir; Vilmundur Gudnason; Thomas Lang

Hip fracture risk is usually evaluated using dual energy X-ray absorptiometry (DXA) or quantitative computed tomography (QCT) which provide surrogate measures for proximal femoral strength. However, proximal femoral strength can best be estimated explicitly by combining QCT with finite element (FE) analysis. To evaluate this technique for predicting hip fracture in older men and women, we performed a nested age- and sex-matched case-control study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort. Baseline (pre-fracture) QCT scans of 5500 subjects were obtained. During 4-7 years follow-up, 51 men and 77 women sustained hip fractures. Ninety-seven men and 152 women were randomly selected as age- and sex-matched controls. FE-strength of the left hip of each subject for stance (F(Stance)) and posterolateral fall (F(Fall)) loading, and total femur areal bone mineral density (aBMD) were computed from the QCT data. F(Stance) and F(Fall) in incident hip fracture subjects were 13%-25% less than in control subjects (p ≤ 0.006) after controlling for demographic parameters. The difference between FE strengths of fracture and control subjects was disproportionately greater in men (stance, 22%; fall, 25%) than in women (stance, 13%; fall, 18%) (p ≤ 0.033), considering that F(Stance) and F(Fall) in fracture subjects were greater in men than in women (p < 0.001). For men, F(Stance) was associated with hip fracture after accounting for aBMD (p = 0.013). These data indicate that F(Stance) provides information about fracture risk that is beyond that provided by aBMD (p = 0.013). These findings support further exploration of possible sex differences in the predictors of hip fracture and of sex-specific strategies for using FE analysis to manage osteoporosis.


Bone | 2011

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.

Fjola Johannesdottir; Kenneth Eric Poole; Jonathan Reeve; Kristin Siggeirsdottir; Thor Aspelund; Brynjolfur Mogensen; Brynjolfur Jonsson; Sigurdur Sigurdsson; Tamara B. Harris; Vilmundur Gudnason; Gunnar Sigurdsson

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/cm², 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.


Acta Orthopaedica | 2005

Short hospital stay augmented with education and home-based rehabilitation improves function and quality of life after hip replacement: randomized study of 50 patients with 6 months of follow-up

Kristin Siggeirsdottir; Orn Olafsson; Halldor Jonsson; Susanne Iwarsson; Vilmundur Gudnason; Brynjolfur Jonsson

Background Because of current cost restrictions, we studied the effect of a shorter hospital stay on function, pain and quality of life (QOL) after total hip replacement (THR). Patients and methods 50 patients from two hospitals were randomized into a study group (SG) of 27 patients receiving preoperative and postoperative education programs, as well as home visits from an outpatient team, and a control group (CG) of 23 patients receiving “conventional” rehabilitation often augmented by a stay at a rehabilitation center. Results Mean hospital stay was shorter for the SG than for the CG (6.4 days and 10 days, respectively; p < 0.001). During the 6-month study period, there were 9 non-fatal complications in the SG and 12 in the CG (p = 0.3). The difference in Oxford Hip Score between the groups was not statistically significant before the operation, but was better for the SG at 2 months (p = 0.03) and this difference remained more or less constant throughout the study. The overall score from the Nottingham Health Profile indicated a better QOL in the SG. Interpretation Our preoperative education program, followed by postoperative home-based rehabilitation, appears to be safer and more effective in improving function and QOL after THR than conventional treatment.


Osteoporosis International | 1992

Differences in fracture pattern between an urban and a rural population: a comparative population-based study in southern Sweden

Brynjolfur Jonsson; Per Gärdsell; Olof Johnell; Inga Redlund-Johnell; Ingemar Sernbo

Differences in the incidence of hip fractures have been reported between urban and rural areas. In this population-based study the characteristics of fracture patterns between the city of Malmö and the nearby rural district of Sjöbo were compared. A total of 782 individuals in Malmö and 486 in Sjöbo were invited to participate. Fracture history for all invited was registered. The odds ratio for fracture was higher in Malmö, particularly for women over 70. More than half of the urban women aged 70 had a history of a fracture. A fourfold increase in fracture prevalence between the ages of 60 and 70 was observed in women in Malmö, whereas the prevalence doubled in Sjöbo. The differences in fracture patterns between these two urban and rural communities may be explained by different lifestyles.


Clinical Rehabilitation | 2002

The timed ‘Up & Go’ is dependent on chair type

Kristin Siggeirsdottir; Brynjolfur Jonsson; Halldor Jonsson; Susanne Iwarsson

Introduction: The timed ‘Up & Go’ (TUG) is a performance test identifying problems in functional mobility. More knowledge on how the type of chair used in uences test results is needed. Objective: To investigate inter-rater agreement on the time score and to assess if chair type used in uenced the performance of the test. Setting: (1) Inter-rater agreement investigation on the time score was carried out with elderly individuals living in a retirement home (n = 31). (2) Four types of chairs were tested on elderly individuals in three different health care centres (n = 100). Results: The two observers were close in timing (mean difference = 0.04 s). From a reference chair the median time for TUG was 15.7 s compared with 16.9 s from a chair with a low seat (p < 0.001). It was signi cantly more dif cult to stand up from a chair without armrests (p < 0.001), and from the lowest chair (p < 0.001), which was also the only chair dif cult to sit down on (p = 0.02). Conclusion: The inter-rater agreement of the time scoring of the TUG has been con rmed. Test performance is dependent on chair type; chairs with armrests and a seating height of 44-47 cm should be used. Clinicians must follow standard procedures and equipment when using the test or else risk invalidating test findings.


Acta Orthopaedica Scandinavica | 1996

Social function after cervical hip fracture. A comparison of hook-pins and total hip replacement in 47 patients.

Brynjolfur Jonsson; Ingemar Sernbo; Åke Carlsson; Hans Fredin; Olof Johnell

47 patients with a cervical hip fracture Garden 3 or 4 and fully ambulatory before the fracture, were randomized to either fixation with Hansson hook-pins (24 patients, median age 79 years) or to a Charnley hip replacement (23 patients, median age 80 years). The patients were followed for 2 years. Social function was evaluated using a standard questionnaire. There were no postoperative deaths and no significant differences in hospital stay. 9/24 patients treated with hook-pins developed healing complications and 2 dislocations occurred in the THR group. After 1 and 2 years, fewer patients treated with hip replacement used outdoor walking aids; they were also more likely to do their own shopping. Hip replacement is a good choice when treating healthy older people with displaced cervical hip fractures, when primary mortality is expected to be low and the risk of healing complications after nailing is high.


Acta Orthopaedica Scandinavica | 1999

Forearm fractures in Malmo, Sweden. Changes in the incidence occurring during the 1950s, 1980s and 1990s

Brynjolfur Jonsson; Urban Bengnér; Inga Redlund-Johnell; Olof Johnell

Between the 1950s and the 1980s, the incidence of forearm fractures increased in the city of Malmö. We have now collected data on all forearm fractures during 1991 and 1992 and compared them with previously published data from 1953-1957 and 1980-1981. During the 1990s, 1314 individuals with wrist fractures and 125 with shaft fractures were recorded. In men, we found a twofold increase in the standardized morbidity ratio (SMR) in the 1990s, compared with the 1950s. The 1990s, compared with the 1980s, showed a reduction in SMR to 0.85. In women, a comparison between the 1990s and the 1950s revealed a slight reduction in SMR, 0.9 during the 1990s. Comparison of the 1990s with the 1980s revealed a reduction in SMR to 0.7 after the age of 70 years. In individuals 60 years and older, we found a fivefold increase in the incidence of fractures of the shaft of the forearm, when comparing the 1990s with the 1980s. In women, the increase in incidence of wrist fractures appears to have been interrupted, when comparing the years 1991-1992 and 1980-1981. Among men, the incidence of wrist fractures appears to be increasing, even after the 1980s. The reduction in incidence among women may partly be explained by warmer winters during 1991-1992.


Bone | 2013

Effect of finite element model loading condition on fracture risk assessment in men and women: the AGES-Reykjavik study.

Joyce H. Keyak; Sigurdur Sigurdsson; G. Karlsdottir; Diana Oskarsdottir; A. Sigmarsdottir; John Kornak; T. B. Harris; Gunnar Sigurdsson; Brynjolfur Jonsson; Kristin Siggeirsdottir; G. Eiriksdottir; V. Gudnason; Thomas Lang

Proximal femoral (hip) strength computed by subject-specific CT scan-based finite element (FE) models has been explored as an improved measure for identifying subjects at risk of hip fracture. However, to our knowledge, no published study has reported the effect of loading condition on the association between incident hip fracture and hip strength. In the present study, we performed a nested age- and sex-matched case-control study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort. Baseline (pre-fracture) quantitative CT (QCT) scans of 5500 older male and female subjects were obtained. During 4-7years follow-up, 51 men and 77 women sustained hip fractures. Ninety-seven men and 152 women were randomly selected as controls from a pool of age- and sex-matched subjects. From the QCT data, FE models employing nonlinear material properties computed FE-strength of the left hip of each subject in loading from a fall onto the posterolateral (FPL), posterior (FP) and lateral (FL) aspects of the greater trochanter (patent pending). For comparison, FE strength in stance loading (FStance) and total femur areal bone mineral density (aBMD) were also computed. For all loading conditions, the reductions in strength associated with fracture in men were more than twice those in women (p≤0.01). For fall loading specifically, posterolateral loading in men and posterior loading in women were most strongly associated with incident hip fracture. After adjusting for aBMD, the association between FP and fracture in women fell short of statistical significance (p=0.08), indicating that FE strength provides little advantage over aBMD for identifying female hip fracture subjects. However, in men, after controlling for aBMD, FPL was 424N (11%) less in subjects with fractures than in controls (p=0.003). Thus, in men, FE models of posterolateral loading include information about incident hip fracture beyond that in aBMD.


Journal of the American Geriatrics Society | 1998

Balance and gait performance in an urban and a rural population

Karin Ringsberg; Per Gärdsell; Olof Johnell; Brynjolfur Jonsson; Karl Obrant; Ingemar Sernbo

OBJECTIVE: To compare the differences in standing balance and gait performance between two populations, correlated with age and physical activities of daily living.

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Sigurdur Sigurdsson

University of Texas Health Science Center at Houston

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Thomas Lang

University of California

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