PubMed Health⌕ Search

Biomedical subjects

Magnus K Karlsson

Publications and source records attributed to Magnus K Karlsson.

At least 19 recordsLinked to original sources
PubMed2007

BMI and objectively measured body fat and body fat distribution in prepubertal children.

BACKGROUND: Body Mass Index (BMI) is often used as a surrogate estimate of body fat in epidemiological studies. This study explores the association between BMI, body fat and body fat distribution assessed by Dual-Energy X-Ray Absorptiometry (DXA) in younger children. METHODS: Cross-sectional study of 246 children (138 boys and 108 girls) aged 8-11 years. DXA was used to quantify abdominal fat mass (AFM), total body fat (TBF) and also total body fat as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. RESULTS: We found close correlations between BMI vs. TBF, BF% and AFM (r = 0.94, r = 0.92 and r = 0.93) for boys and (r = 0.95, r = 0.92 and r = 0.95) for girls, respectively (P<0.05 for all r-values). However, significantly lower correlation (P<0.001 for difference between the r-values) existed for body fat distribution (r = 0.64 for boys and 0.73 for girls). CONCLUSION: Percentage body fat, TBF and AFM were all closely associated with BMI, suggesting that BMI serves as a good surrogate marker for obesity in population studies. However, a significantly lower correlation existed for BMI vs. body fat distribution, which may be a limitation when BMI is used to study cardiovascular risk factors in epidemiological studies.

Adipose Tissue↗
PubMed2006

Gender differences and determinants of aerobic fitness in children aged 8-11 years.

Previous studies of gender differences in maximum oxygen uptake have come to different conclusions. Limited data exists where the determinants of maximum oxygen uptake have been evaluated in a comprehensive manner. Thus, we examined 248 children (140 boys and 108 girls), aged 7.9-11.1 years. Body composition was determined by dual-energy X-ray absorptiometry, measured variables were total body fat (TBF) and lean body mass (LBM). Maximal oxygen uptake (VO2peak) was measured by indirect calorimetry during a maximal cycle exercise test. Daily physical activity was assessed by accelerometers and duration of vigorous activity per day (VPA) was calculated. Left ventricular inner diastolic diameter (LVDD) was measured by echocardiography. Lung function was evaluated with spirometric testing and whole body plethysmography. Boys had between 8 and 18% higher values than girls for VO2peak, dependent upon whether VO2peak was expressed in absolute values or scaled to body mass, LBM or if allometric scaling was used. In multiple regression analysis absolute values of aerobic fitness were independently related to LBM, maximal heart rate (Max HR), gender, LVDD, and VPA. Furthermore, when VO2peak was scaled to body mass it was independently related to ln TBF, Max HR, gender, VPA, and LVDD. Lung function had no relation to VO2peak. Our study concludes that body composition is the main predictor for VO2peak, in children aged 8-11 years, whereas VPA or LVDD has only a modest impact. Existing gender differences in VO2peak cannot be explained only by differences in body composition, physical activity, or heart size.

Body Composition↗
PubMed2006

Daily physical activity and its relation to aerobic fitness in children aged 8-11 years.

A positive relationship between daily physical activity and aerobic fitness exists in adults. Studies in children have given conflicting results, possibly because of differences in methods used to assess daily physical activity and fitness. No study regarding daily physical activity and fitness in children has been published, where fitness has been assessed by direct measurement of maximum oxygen uptake and related to daily physical activity intensities by accelerometers. We examined 248 children (140 boys and 108 girls), aged 7.9-11.1 years. Maximum workload and maximal oxygen uptake (VO2PEAK) by indirect calorimetry were measured during a maximum bicycle ergometer exercise test. Exercise capacity was adjusted for body mass and (body mass)2/3. Daily physical activity was evaluated by accelerometers, worn around the waist for 4 days. Mean accelerometer counts and time spent in vigorous physical activity were calculated. VO2PEAK was correlated with mean accelerometer counts (r=0.23 for boys and r=0.23 for girls, both P<0.05), but somewhat better with time spent in vigorous activity (r=0.32 for boys, r=0.30 for girls, both P<0.05). All results remained virtually the same regardless of the method used to adjust for differences in body size.

Body Size↗
PubMed2006

Leptin is closely related to body fat in prepubertal children aged 8-11 years.

BACKGROUND: In adults and obese children, serum leptin concentrations are closely related to body fat. AIM: To investigate whether such a relationship between leptin concentrations and body fat is also evident in children with a relatively normal body composition. METHODS: The study was a cross-sectional population study in 170 Caucasian children (91 boys and 79 girls), with a mean age of 9.9+/-0.6 y (range 8.5-10.9 y) and a mean BMI of 17.4+/-2.6 (range 12.8-28.1). Serum leptin was measured and compared to total body fat as determined by dual-energy X-ray absorptiometry. RESULTS: In the whole population, serum leptin concentrations were highly correlated with total body fat (r=0.83, p<0.001). A stepwise forward multi-regression analysis revealed that the inclusion of other anthropometrical data did not add any significance to the model. Leptin concentrations were significantly higher in girls (5.2 ng/ml) than in boys (3.2 mg/ml; p=0.003). Gender differences still prevailed (p=0.007) after adjusting for number of kilograms of fat tissue. CONCLUSION: This study shows that, already at the young age of 9-11 y, an adult-like pattern of regulation of leptin exists. This indicates similar risk factor dependency of leptin across all age groups.

Absorptiometry, Photon↗
PubMed2006

A school curriculum-based exercise program increases bone mineral accrual and bone size in prepubertal girls: two-year data from the pediatric osteoporosis prevention (POP) study.

UNLABELLED: This 2-year prospective controlled exercise intervention trial in 99 girls at Tanner stage 1, evaluating a school curriculum-based training program on a population-based level, showed that the annual gain in BMC, aBMD, and bone size was greater in the intervention group than in the controls. INTRODUCTION: Most exercise intervention studies in children, evaluating the accrual of BMD, include volunteers and use specifically designed osteogenic exercise programs. The aim of this study was to evaluate a 2-year general school-based exercise intervention program in a population-based cohort of girls at Tanner stage 1. MATERIALS AND METHODS: Forty-nine girls 7-9 years of age in grades 1 and 2 in one school were included in a school curriculum-based exercise intervention program of general physical activity for 40 minutes per school day (200 minutes/week). Fifty healthy age-matched girls in three neighboring schools, assigned to the general Swedish school curriculum of physical activity (60 minutes/week), served as controls. All girls were premenarchal, remaining in Tanner stage 1 during the study. BMC (g) and areal BMD (aBMD; g/cm2) were measured with DXA of the total body (TB), the lumbar spine (L2-L4 vertebrae), the third lumbar vertebra (L3), the femoral neck (FN), and the leg. Volumetric BMD (vBMD; g/cm3) and bone size were calculated at L3 and FN. Total lean body mass and total fat mass were estimated from the total body scan. Height and weight were also registered. Baseline measurements were performed before the intervention was initiated. Follow-up was done after 2 years. RESULTS: No differences between the groups were found at baseline in age, anthropometrics, or bone parameters. The annual gain in BMC was greater in the intervention group than in the controls: L2-L4, mean 3.8 percentage points (p = 0.007); L3 vertebra, mean 7.2 percentage points (p < 0.001); legs, mean 3.0 percentage points (p = 0.07). The intervention group had a greater annual gain in aBMD: total body, mean 0.6 percentage points (p = 0.006), L2-L4, mean 1.2 percentage points (p = 0.02), L3 vertebra, mean 1.6 percentage points (p = 0.006); legs, mean 1.2 percentage points (p = 0.007). There was also a greater mean annual gain in bone size in the L3 vertebra (mean 1.8 percentage points; p < 0.001) and in the FN (mean 0.3 percentage points; p = 0.02). CONCLUSIONS: A general school-based exercise program for 2 years for 7- to 9-year-old girls (baseline) enhances the accrual of BMC and BMD and increases bone size.

Bone and Bones↗
PubMed2006

Primary nonoperative treatment of moderately displaced two-part fractures of the radial head.

BACKGROUND: Moderately displaced two-fragment fractures of the radial head have been treated predominantly nonoperatively. Recently, however, open reduction and internal fixation has gradually gained interest, without clear evidence that initial nonoperative treatment leads to an unfavorable outcome. As a consequence, the purpose of the present study was to evaluate the long-term outcome after the initial nonoperative treatment of this type of fracture. METHODS: Fifteen men and thirty-four women, with a mean age of forty-nine years at the time of the injury, were included in the study. All patients initially had been managed nonoperatively for a two-fragment fracture of the radial head that was displaced 2 to 5 mm and that included >/=30% of the joint surface (a Mason type-IIa fracture). Early mobilization had been used for twenty-seven patients, and cast immobilization for a mean of two weeks (range, one to four weeks) had been used for twenty-two. All patients were reevaluated with a questionnaire after a mean of nineteen years, and thirty-four also had a clinical and a radiographic evaluation. Six patients had had a delayed radial head excision because of an unsatisfactory primary outcome. RESULTS: Forty of the forty-nine patients had no subjective complaints, eight were slightly impaired as the result of occasional elbow pain, and one had daily pain. Flexion was slightly impaired in the injured elbows as compared with the uninjured elbows (137 degrees +/- 8 degrees compared with 139 degrees +/- 7 degrees ), as was extension (-3 degrees +/- 7 degrees compared with 1 degrees +/- 5 degrees ) and supination (86 degrees +/- 7 degrees compared with 88 degrees +/- 4 degrees ) (p < 0.05 for all comparisons). The prevalence of degenerative changes on radiographs was higher for the injured elbows than for the uninjured elbows (82% [twenty-eight of thirty-four] compared with 21% [seven of thirty-four]; p < 0.01). CONCLUSIONS: The initial nonoperative treatment of Mason type-IIa fractures of the radial head that are displaced by 2 to 5 mm is associated with a predominantly favorable outcome, especially if a delayed radial head excision is performed in the few cases in which the early outcome is unsatisfactory. LEVEL OF EVIDENCE: Therapeutic Level IV.

Adolescent↗
PubMed2005

Fracture-induced changes in bone turnover: a potential confounder in the use of biochemical markers in osteoporosis.

To examine the short- and long-term bone metabolic effects of fracture assessed by biochemical markers, we utilized a clinical fracture model-proximal tibial osteotomy-and prospectively followed 14 patients. This model of an induced fracture of a major bone gives the advantage of assessing baseline levels prior to fracture. Follow-up occurred at 6-9 weeks, 4-7 months, 9-13 months, and 14-17 months after fracture. Serum was assayed for type 1 procollagen peptide (PICP), total alkaline phosphatase (ALP), and carboxy-terminal-telopeptide of type I collagen (ICTP), while deoxypyridinoline (Dpyr) was measured in urine. Serum osteocalcin (OC) was measured using two recently developed two-site immunofluorometric assays, which both measure full-length and fragmented forms of OC (OCtot), with one of the assays specifically detecting only the carboxylated form of OC (OCcxy). In addition, OC was measured in urine using the same assays as those used for serum. Serum OCtot increased to a peak at 4-7 months after fracture (P < 0.001) and a similar increase was seen for OCcxy (P < 0.05) and ALP (P < 0.01). Bone formation had returned to baseline after a year. Dpyr increased significantly, with a doubling at 6 weeks, while serum (S)-ICTP increased by 73% (P < 0.01 and P < 0.001). Urine OC increased to a maximum of 84% at 6 weeks. The initial percentage increase of bone resorption was greater than that of bone formation. We conclude that: (1) bone turnover as measured by biochemical markers is altered soon after fracture, (2) the major changes occur within 6 weeks to 6 months, but may persist for up to a year. (3) The initial increase in bone resorption exceeds the increase in bone formation, which may contribute to the enhanced bone loss after fracture. (4) The two novel urine OC assays show a similar pattern of change as established marks of bone resorption, which may indicate that they measure bone resorption. (5) Fracture-induced effects on bone turnover are significant and, thus, are potential confounders in the assessment of osteoporosis.

Adult↗
PubMed2005

Maternity and bone mineral density.

During pregnancy and lactation, changes occur in a variety of factors which have great potential to influence bone mineral density (BMD). Smoking habits, the level of alcohol consumption, the level of physical activity, body weight, soft tissue composition and hormone levels are all factors that change during the course of these conditions. Some of these factors are capable of increasing BMD, and some can reduce it. Due to these various changes, it is virtually impossible to predict the development in BMD that will occur during a pregnancy and lactation. However, longitudinal studies have suggested that both pregnancy and lactation are associated with a BMD loss of up to 5%, albeit that the BMD recovers after weaning. Cross-sectional studies have indicated that women with many children and a long total period of lactation have similar or higher BMD and similar or lower fracture risk than their peers who have not given birth. As the studies showing this trend have been observational and cross sectional case-control studies, the conclusions can only be regarded as being suggestive, and no causality can be proven.

Bone Density↗
PubMed2005

Vertebroplasty and kyphoplasty: New treatment strategies for fractures in the osteoporotic spine.

During the last decade, two new treatment modalities for osteoporotic vertebral fractures have gained more interest: percutaneous vertebroplasty and kyphoplasty. The techniques and the short-term clinical results and complications have been presented but there is no scientific evidence-based information regarding the efficacy of the procedures, such as randomized controlled trials (RCT). Instead, we have to rely on prospective and retrospective uncontrolled short-term observational studies and case-control studies. These studies have shown consistently that the short-term results after the procedures are favorable as regards both pain relief and functional status. It is currently unknown, however, whether a vertebroplasty or a kyphoplasty gives a better outcome than nonoperative treatment, and whether the long-term results are as favorable as the short-term results.

Humans↗
PubMed2004

Hip revision using the Exeter stem, impacted morselized allograft bone and cement: a consecutive 5-year radiostereometric and radiographic study in 15 hips.

BACKGROUND: Impaction grafting in hip revision surgery is widely used but studies with mid- and long-term follow-up are scarce. PATIENTS, METHODS AND RESULTS: A 5-year radiostereometric (RSA) follow-up of 15 hip revisions with the Exeter stem, morselized impacted allograft bone and cement revealed that 3 stems had not migrated between 2 and 5 years after revision, 11 stems had migrated to a minor degree in at least 1 direction, and 1 stem was loose according to RSA but without any radiographic signs of loosening or pain. The pain score was comparable to primary arthroplasties. INTERPRETATION: From a 5-year perspective, first-time hip revisions for aseptic loosening with impacted morselized allograft bone and cement appear to yield good clinical results, although stem migration continues to a minor degree 2 years after revision.

Aged↗
PubMed2004

An age-related medullary expansion can have implications for the long-term fixation of hip prostheses.

BACKGROUND: Diaphyseal bone loss occurs mainly at the endosteal surface in the medullary cavity. Since the menopause is followed by an increase in bone loss, the size of the medullary cavity should theoretically increase during the postmenopausal period. If so, this might affect the long-term fixation of hip prostheses. PATIENTS AND METHODS: This 19-year prospective study evaluated bone loss and geometrical changes in 112 women, all premenopausal at baseline. Bone mineral density (BMD) and skeletal geometry, with special reference to the size of the medullary cavity, were estimated every other year by single-photon absorptiometry at the cortical site of the distal radius. RESULTS: After menopause, a decrease of 1.7 (95% CI 1.6-1.8)% occurred in the BMD every year, while an increase of 0.9 (0.8-1.0)% in the medullary width (endosteal width) too place every year. The annual change in BMD was inversely correlated with the annual change in the medullary width (r = -0.5, p < 0.001). The quartile of women with the largest BMD loss had a greater medullary expansion than the quartile of women with the least BMD loss (p < 0.001). INTERPRETATION: If the age-related expansion of the radial medullary cavity is a general phenomenon, this may have implications for the long-term fixation of hip prostheses.

Absorptiometry, Photon↗
PubMed2004

Screening for low bone mineral density with quantitative ultrasound within the primary health care system.

OBJECTIVE: To screen risk groups for low bone mineral density by quantitative ultrasound in primary health care. DESIGN: Cross-sectional. INTERVENTION: None. SUBJECTS: Risk categories for osteoporosis (a fragility fracture, malabsorption, immobilisation, inflammatory joint disease, glucocorticoid, fenantoin or thyroxin treatment, renal insufficiency or "miscellaneous"), 775 women and 179 men aged between 40 and 93 were measured. MAIN OUTCOME MEASURES: Calcaneus quantitative ultrasound stiffness index T-score below -2.5 standard deviation (SD). RESULTS: 41% of women and 24% of men and more than 80% of women and 50% of men over the age of 80, within the risk groups, had a stiffness index T-score below -2.5 SD. All over 80 years with a fragility fracture had a stiffness index T-score below -2.5 SD. Men aged 50-59 within the risk groups had lower stiffness index T-scores than controls (-1.4 versus -0.6, p = 0.05). Individuals with a fragility fracture had lower stiffness index T-scores than controls, women aged 70-79 years (-3.1 versus -2.4, p < 0.05) and men aged 60-69 years (-2.3 versus -1.2, p < 0.05). CONCLUSION: Quantitative ultrasound calcaneus used in gender-specific, diagnosis-specific and age-specific cohorts can capture individuals with low bone mass.

Adult↗
PubMed2004

Long term effects of oestrogen therapy on bone loss in postmenopausal women: a 23 year prospective study.

OBJECTIVE: To determine the long term effect of oestrogen therapy on bone loss after menopause. DESIGN: Prospective observational study over 23 years. SETTING: Malmö, Sweden. SUBJECTS: Twenty-eight women taking oestrogen and 196 women not taking oestrogen during the follow up. METHODS: Bone mineral density of the forearm was measured by single-photon absorptiometry at age 48 and 72 years. Use of oestrogen therapy was noted. MAIN OUTCOME MEASURE: Rate of forearm bone loss between the age of 48 and 72 years. RESULTS: Women taking oestrogen, for a median of 17 years (range 4 to 26), had 8.7 percentage points (95% CI 3.8-13.5) lower rate of bone loss compared with women not taking oestrogen during the same period. Each year of oestrogen therapy reduced the rate of bone loss by 0.8 percentage points (95% CI 0.2-1.4). CONCLUSIONS: The use of oestrogen seems to reduce the rate of bone loss over a period of 23 years, and the longer the duration of the therapy, the less bone loss.

Absorptiometry, Photon↗
PubMed2004

Fractures of the radial head and neck treated with radial head excision.

BACKGROUND: The reported long-term outcomes of the treatment of radial head and neck fractures with excision of the radial head have been mixed. The purpose of the present study was to evaluate the long-term outcomes of primary or delayed radial head excision for the treatment of these fractures. METHODS: Sixty-one individuals (mean age, forty-four years) with thirty-nine Mason type-II, ten Mason type-III, and twelve Mason type-IV fractures were evaluated subjectively, objectively, and radiographically at a mean of eighteen years (range, eleven to thirty-three years) after treatment. Forty-three fractures were treated with primary radial head excision, and the remaining eighteen were treated with delayed radial head excision at a median of five months (range, one to 238 months) after the injury. RESULTS: At the time of follow-up, twenty-eight individuals had no symptoms, twenty-seven had occasional elbow pain, and six had daily pain. Four individuals with daily pain had had a Mason type-IV fracture. The range of motion of the formerly injured upper extremities was slightly less than that of the uninjured upper extremities in terms of flexion (139 degrees +/- 11 degrees compared with 142 degrees +/- 8 degrees ), extension (-7 degrees +/- 12 degrees compared with -1 degrees +/- 6 degrees ), and supination (77 degrees +/- 20 degrees compared with 85 degrees +/- 10 degrees ) (all p < 0.01). A higher percentage of formerly injured elbows than uninjured elbows had cysts, sclerosis, and osteophytes (73% compared with 7%; p < 0.001), but none had a reduced joint space. No differences were found between the outcomes for individuals treated with a primary radial head excision and those for individuals treated with a delayed excision. CONCLUSIONS: Following a displaced radial head or neck fracture, excision of the radial head often leads to a good or fair result. We found no differences in outcome between primary and delayed radial head excisions following a Mason type-II, III, or IV fracture. The outcomes are associated with the type of fracture, with Mason type-IV fractures having the worst results, rather than with the timing of the radial head excision (primary or delayed).

Adolescent↗
PubMed2003

A modeling capacity of vertebral fractures exists during growth: an up-to-47-year follow-up.

STUDY DESIGN: The study is an observational cohort study. OBJECTIVES: To determine the incidence and the long-term outcome of thoracic or lumbar vertebral fractures in children. SUMMARY OF BACKGROUND DATA: The incidence of vertebral fractures in children is described as rare and the outcome as favorable. However, no studies evaluate the clinical and radiographic long-term outcome and if a fractured vertebra could be rebuilt during growth. METHOD: The incidence of vertebral fractures in children was evaluated through the radiographic archives. Twelve boys and 12 girls, aged 7-16 when sustaining the fracture, 21 one-column compression fractures and 3 burst fractures Denis type B, all without neurologic deficits, attended the follow-up. Primary treatment consisted of immediate mobilization without brace. Clinical and radiographic examinations were performed 27-47 years after the injury. RESULTS: The annual incidence of thoracic and lumbar vertebral body fractures in individuals below age 16 was 0.07%. Twenty-one individuals had, at follow-up, no subjective complaints, 3 had occasional back pain (Oswestry Scores 8, 22, and 26), 23 were classified as Frankel E, and 1 as Frankel D. The radiographic ratio anterior height/posterior height of the fractured vertebral body increased from 0.75 after injury to 0.87 at follow-up (P < 0.001). The posttraumatic kyphosis in the fractured region decreased in 8 individuals (33%), all aged 13 or less at fracture. No increased disc degeneration was observed. CONCLUSION: Thoracolumbar vertebral fractures without neurologic deficits, sustained during growth, have a favorable long-term outcome. A modeling capacity, reducing the fracture deformity, exists at least in the youngest patients.

Adolescent↗
PubMed2003

Bone loss and bone size after menopause.

BACKGROUND: Bone loss increases after menopause. However, bone strength also depends on structural characteristics such as bone size. Whether bone size increases as a result of periosteal apposition and whether a strength index accounting for both bone density and bone size might predict the risk of fracture better than bone density alone are unclear. METHODS: Bone mass and the skeletal structure of the distal radius were evaluated by single-photon absorptiometry every other year in 108 women, all of whom were followed from the time of menopause for a mean period of 15 years. Postmenopausal serum estradiol levels and fractures of the distal radius were noted. RESULTS: The mean (+/-SD) annual decrease in bone mineral density was 1.9+/-0.7 percent. The medullary bone diameter increased annually by 1.1+/-0.9 percent, and the periosteal diameter by 0.7+/-0.3 percent; the strength index decreased by 0.7+/-0.7 percent. The expansion of the medullary diameter and the expansion of the periosteal diameter were correlated with one another (r = 0.54, P<0.001), and women in the highest quartile of medullary expansion had more loss of bone mineral density and greater periosteal apposition than women in the lowest quartile (P<0.001 for both comparisons). The postmenopausal serum estradiol level was correlated with changes in the periosteal diameter (r = -0.25, P=0.009) and with changes in bone mineral density (r = 0.34, P<0.001). A 1-SD decrement in the strength index at base line was associated with a risk ratio for fracture of the distal radius of 3.8 (95 percent confidence interval, 1.8 to 8.0). CONCLUSIONS: Increased bone loss after menopause is associated with increased periosteal apposition, which partially preserves bone strength. A strength index may be a helpful predictor of the risk of fracture.

Biomechanical Phenomena↗
PubMed2003

Fracture of the radial head and neck of Mason types II and III during growth: a 14-25 year follow-up.

Twenty-four individuals, who were 16 years of age or younger when they sustained a fracture of the radial head or neck, were examined at a mean of 19 years (range 14-25 years) after injury. The 12 girls and 12 boys were a mean age of 11 years (range 5-16 years) when the fracture was sustained. Two were excluded due to late resection of the radial head following persisting pain. The fractures, which were of Mason type II in 19 and type III in three cases, were treated by mobilization in eight cases, plaster in eight, open reduction and internal fixation in three and closed reduction and plaster in three. At the follow-up examination, 19 (86%) had no complaints, while three (14%) had occasional pain. Flexion was decreased in the formerly injured compared with the uninjured elbow (139 +/- 8 degrees versus 142+/-5 degrees; P<0.05). None had developed elbow osteoarthritis. Isolated, closed fracture of the radial head and neck during growth has a favourable, long-term outcome.

Adolescent↗