Papers by Magnus K Karlsson
Deutsche Zeitschrift für Sportmedizin, 2012
Low muscle strength is an important heritable indicator of poor health linked to morbidity and mo... more Low muscle strength is an important heritable indicator of poor health linked to morbidity and mortality in older people. In a genome-wide association study meta-analysis of 256,523 Europeans aged 60 years and over from 22 cohorts we identified 15 loci associated with muscle weakness (European Working Group on Sarcopenia in Older People definition: n=48,596 cases, 18.9% of total), including 12 loci not implicated in previous analyses of continuous measures of grip strength. Loci include genes reportedly involved in autoimmune disease (HLA-DQA1 p=4*10-17), arthritis (GDF5 p=4*10-13), cell cycle control and cancer protection, regulation of transcription, and others involved in the development and maintenance of the musculoskeletal system. Using Mendelian randomization we report possible overlapping causal pathways, including diabetes susceptibility, hematological parameters, and the immune system. We conclude that muscle weakness in older adults has distinct mechanisms from continuous...
The American Journal of Clinical Nutrition, 2018
Background: Lean body mass (LM) plays an important role in mobility and metabolic function. We pr... more Background: Lean body mass (LM) plays an important role in mobility and metabolic function. We previously identified five loci associated with LM adjusted for fat mass in kilograms. Such an adjustment may reduce the power to identify genetic signals having an association with both lean mass and fat mass. Objectives: To determine the impact of different fat mass adjustments on genetic architecture of LM and identify additional LM loci. Methods: We performed genome-wide association analyses for whole-body LM (20 cohorts of European ancestry with n = 38,292) measured using dual-energy X-ray absorptiometry) or bioelectrical impedance analysis, adjusted for sex, age, age 2 , and height with or without fat mass adjustments (Model 1 no fat adjustment; Model Conclusions: In conclusion, we identified one novel LM locus (TNRC6B). Our results suggest that a genetically determined increase in lean mass might exert either harmful or protective effects on metabolic traits, depending on its relation to fat mass.
Bone Traits Seem to Develop Also During the Third Decade in Life-Normative Cross-Sectional Data on 1083 Men Aged 18-28 Years
Journal of clinical densitometry : the official journal of the International Society for Clinical Densitometry, Jan 18, 2016
By identifying individuals with low peak bone mass (PBM) at young age, early targeted interventio... more By identifying individuals with low peak bone mass (PBM) at young age, early targeted interventions to reduce future fracture risk could be possible. Peripheral quantitative computed tomography (pQCT) is in many ways superior to the gold standard dual-energy X-ray absorptiometry (DXA), as cortical and trabecular compartments as well as the volumetric density and bone structure can be examined separately. Because each of these traits contributes independently to bone strength, it is probable that pQCT provides an even better fracture risk estimation than DXA. Currently, the clinical applications of pQCT are limited partly because comprehensive normative pQCT data, especially in young men, are not readily available. We therefore set up a study in young men with the following objectives: (1) to identify peak ages in pQCT bone traits with special reference to PBM and peak bone strength; and (2) to provide normative pQCT data. We measured volumetric bone mineral density and structural pa...
Former male elite athletes sustain fewer fragility fractures than expected
Proceedings of the Physiological Society, 2012
A seven‐year physical activity intervention for children increased gains in bone mass and muscle strength
Acta Paediatrica, 2016
AimThis study evaluated the musculoskeletal effects of increased physical activity on children, s... more AimThis study evaluated the musculoskeletal effects of increased physical activity on children, starting at six to nine years of age.MethodsIn one school we increased the physical education of 72 girls and 100 boys to 200 minutes per week over seven years. In three other schools, 45 girls and 47 boys continued to receive 60 minutes per week. We measured areal bone mineral density (aBMD) with dual energy X‐ray absorptiometry and muscle strength with computerised dynamometer at baseline and after seven years and tibial cortical thickness with peripheral quantitative computed tomography after seven years.ResultsGirls in the intervention group gained 0.04 g/cm2 (0.01–0.08) more total spine aBMD (p < 0.05) and 6.2Nm (1.6, 10.7) more knee flexion strength (p < 0.01) than control group girls and had a 0.1 mm (0.0, 0.3) higher tibial cortical thickness at follow‐up (p < 0.05). Boys in the intervention group gained 7.3Nm (0.4, 14.2) more knee extension strength (p < 0.05) and 7.4...
Bone mass in athletes during and after career
Osteoporosis International, 1996
ABSTRACT Without Abstract
International journal of pediatrics, 2010
This prospective controlled intervention study over 12 months evaluated the effect of exercise on... more This prospective controlled intervention study over 12 months evaluated the effect of exercise on muscular function, physical ability, and body composition in pre-pubertal boys. Sixty-eight boys aged 6-8 years, involved in a general school-based exercise program of 40 min per school day (200 min/week), were compared with 46 age-matched boys who participated in the general Swedish physical education curriculum of mean 60 min/week. Baseline and annual changes of body composition were measured by dual energy X-ray absorptiometry (DXA), stature, and body mass by standard equipments, isokinetic peak torque (PT) of the knee extensors, and flexors at 60 and 180 deg/sec by computerized dynamometer (Biodex) and vertical jump height (VJH) by a computerized electronic mat. The annual gain in stature and body mass was similar between the groups whereas the increase in total body and regional lean mass (P < .001) and fat mass (P < .001) was greater in the exercise group. The one-year gain ...
Complications After Transpedicular Stabilization of the Spine
SPINE, 1994
The authors studied complications of transpedicular stabilization methods. One hundred and sixty-... more The authors studied complications of transpedicular stabilization methods. One hundred and sixty-three consecutive transpedicular stabilization procedures were performed between January 1987 and December 1991. The indications for stabilization were trauma (33 cases), metastatic spinal disorder (30 cases), spinal stenosis (33 cases), spondylolisthesis (27 cases), ankylosing spondylitis (6 cases), low back pain (22 cases), and miscellaneous (12 cases). Patients records and the entire series of radiographs for each case were scrutinized by independent observers. All per- and postoperative complications, including implant loosening and fatigue, were recorded. Clinical and radiographic survivorship analyses of the implants were performed. Early complications were unusual and none were associated with permanent morbidity. The probability of not having the implant removed in the first postoperative year was 85%. There was a 40% risk of radiographic failure, defined as loosening or implant fatigue, at 6 months. The outcome was more favorable in cases in which anterior vertebral interbody fusion was also performed. Transpedicular fixation is a safe procedure with a low incidence of serious per- and early postoperative complications. The mechanical durability of transpedicular fixators used alone is a cause for concern.
Exercise, bone mass and bone size in prepubertal boys: one‐year data from the pediatric osteoporosis prevention study
Scandinavian Journal of Medicine & Science in Sports, 2006
This non‐randomized prospective controlled study evaluates a daily school‐based exercise interven... more This non‐randomized prospective controlled study evaluates a daily school‐based exercise intervention program of 40 min/school day for 1 year in a population‐based cohort of 81 boys aged 7–9 years. Controls were 57 age‐matched boys assigned to the general school curriculum of 60 min/week. Bone mineral content (BMC; g) and areal bone mineral density (aBMD; g/cm2) were measured with dual X‐ray absorptiometry (DXA) of the total body, the third lumbar vertebra (L3) and the femoral neck (FN). Bone width for L3 and FN was calculated from the lumbar spine and hip scan. No differences between the groups were found at baseline in age, anthropometrics or bone parameters. The mean annual gain in L3 BMC was 5.9 percentage points higher (P<0.001), L3 aBMD a mean 2.1 percentage points higher (P=0.01) and L3 width a mean 2.3 percentage points higher (P=0.001) in the cases than in the controls. When all individuals were included in one cohort, the total duration of exercise including both school...
Exercise May Induce Reversible Low Bone Mass in Unloaded and High Bone Mass in Weight-Loaded Skeletal Regions
Osteoporosis International, 2001
Exercise during growth and adolescence increases bone mineral density (BMD) in weight-loaded skel... more Exercise during growth and adolescence increases bone mineral density (BMD) in weight-loaded skeletal regions. The development of BMD in unloaded or minimally loaded regions during activity is unclear. We measured BMD in one unloaded, one partly loaded and one highly loaded skeletal region in 67 active soccer players, mean age 22.7 years (range 17-35 years), 128 former soccer players, mean age 54.0 years (range 19-85 years) and 138 controls, mean age 50.6 years (range 19-80 years). The active soccer players played at three different levels: premier league, 3rd league or 6th league. Duration of exercise in these three grou s was 12, 8 and 6 h/week, respectively. BMD (g/cm ) was measured by dual-energy X-ray absorptiometry (DXA) in the upper part of the skull (the unloaded skeletal region), the arms (the partly loaded region) and the femoral neck (the maximal loaded region). Data are presented as mean +/- SD. Active soccer players had 10.3 +/- 10.4% lower BMD in the upper part of the skull (p &amp;amp;amp;amp;lt; 0.001), 1.4 +/- 6.3% higher BMD in the arm (NS) and 12.7 +/- 9.8% higher BMD in the femoral neck (p&amp;amp;amp;amp;lt;0.001) compared with age- and gender-matched controls. All three levels of soccer players demonstrated, independent of activity level, the same discrepancies in BMD compared with controls. Former soccer players had lower BMD in the upper part of the skull until age 70 years and higher BMD in the femoral neck until age 50 years compared with controls. The BMD of the arm was not different in former soccer players compared with controls. In summary, active soccer players had lower BMD in the unloaded skeletal region, no difference in BMD in the partly loaded region and higher BMD in the weight-loaded region compared with controls. The discrepancies compared with controls diminished with age so that no differences were found in BMD after age 70 years. In conclusion, unloaded and weight-loaded skeletal regions may respond differently to increased and decreased physical activity.
Muscle Determinants of Bone Mass, Geometry and Strength in Prepubertal Girls
Medicine & Science in Sports & Exercise, 2008
The aim of this study was to compare the relative contribution of peak muscle force (isokinetic p... more The aim of this study was to compare the relative contribution of peak muscle force (isokinetic peak torque) with surrogate estimates of muscle force, including leg lean tissue mass (LTM) and vertical jump height (VJH), on bone mass, geometry and strength in healthy prepubertal girls (n = 103). Total leg and FN BMC and leg LTM were measured by DXA; the hip strength analysis program was used to assess FN diameter, cross-sectional area (CSA) and section modulus (Z). Isokinetic peak torque of the knee extensors and flexors (60 degrees .s) were used as direct measures of peak muscle force. VJH was measured as an estimate of neuromuscular function. Total leg length or femoral length was used as a surrogate measure of moment arm length. All estimates of muscle function, except VJH, were positively associated with leg BMC (r = 0.72 - 0.90) and FN BMC, geometry and strength (r = 0.35-0.65) (all, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Multiple linear regression analyses revealed that leg LTM and isokinetic peak torque were independently and equally predictive of leg BMC and FN BMC, bone geometry and strength, explaining 8 to 28% of the variance in each of the bone traits after accounting for moment arm length. When isokinetic peak torque was corrected for both leg LTM and moment arm length, it remained an independent predictor of BMC, CSA and Z, but only accounted for an additional 2 to 5% of the variance. These data suggest that DXA-derived leg LTM can be used as a reasonable surrogate for isokinetic peak muscle forces when assessing bone strength in relation to muscular function in healthy pre-pubertal girls.
Association Between Changes in Habitual Physical Activity and Changes in Bone Density, Muscle Strength, and Functional Performance in Elderly Men and Women
Journal of the American Geriatrics Society, 2008
OBJECTIVES: To investigate the long‐term effects of habitual physical activity on changes in musc... more OBJECTIVES: To investigate the long‐term effects of habitual physical activity on changes in musculoskeletal health, functional performance, and fracture risk in elderly men and women.DESIGN: Ten‐year prospective population‐based study.SETTING: Malmö‐Sjöbo Prospective Study, Sweden.PARTICIPANTS: Participants were 152 men and 206 women aged 50, 60, 70, and 80 who were followed for 10 years.MEASUREMENTS: Distal radius bone mineral density (BMD) (single photon absorptiometry), upper limb muscle (grip) strength, balance, gait velocity, occupational and leisure‐time activity, and fractures (interview‐administered questionnaire) were reassessed after 10 years. Annual changes for all measures were compared between participants with varying habitual physical activity histories at baseline and follow‐up: inactive–inactive (n=202), active–inactive (n=47), inactive–active (n=49), and active–active (n=60). Data for men and women were pooled, because there were no sex‐by‐activity group interacti...
Smoking Predicts Incident Fractures in Elderly Men: Mr OS Sweden
Journal of Bone and Mineral Research, 2009
The aim of this study was to investigate the association between smoking and bone mineral density... more The aim of this study was to investigate the association between smoking and bone mineral density (BMD) and radiographically verified prevalent vertebral fractures and incident fractures in elderly men. At baseline 3003 men aged 69 to 80 years of age from the Swedish Mr Os Study completed a standard questionnaire concerning smoking habits and had BMD of the hip and spine measured using dual-energy X-ray absorptiometry (DXA); 1412 men had an X-ray of the thoracic- and lumbar spine. Radiologic registers were used to confirm reported new fractures after the baseline visit. At baseline, 8.4% were current smokers. Current smokers had a 6.2% lower BMD at the total hip and a 5.4% lower BMD at the lumbar spine (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). Current smoking remained independently inversely associated with BMD at the hip and lumbar spine after adjusting for age, height, weight, calcium intake, physical activity, and centers as covariates. Prevalent vertebral fractures among current smokers were increased in unadjusted analyses [odds ratio (OR) = 1.90, 95% confidence interval (CI) 1.26-2.87] and after adjustment for lumbar BMD (OR = 1.67, 95% CI 1.09-2.55). Smokers had a high risk for two or more prevalent vertebral fractures (OR = 3.18, 95% CI 1.88-5.36). During the average follow-up of 3.3 years, 209 men sustained an X-ray-verified fracture. Incident fracture risk among smokers was calculated with Cox proportional hazard models. Current smokers had an increased risk of all new fractures [hazard ratio (HR) = 1.76, 95% CI 1.19-2.61]; nonvertebral osteoporotic fractures, defined as humerus, radius, pelvis, and hip fractures (HR = 2.14, 95% CI 1.18-3.88); clinical and X-ray-verified vertebral fractures (HR = 2.53, 95% CI 1.37-4.65); and hip fractures (HR = 3.16, 95% CI 1.44-6.95). After adjustment for BMD, including other covariates, no significant association between smoking and incident fractures was found. Current tobacco smoking in elderly men is associated with low BMD, prevalent vertebral fractures, and incident fractures, especially vertebral and hip fractures.
Muscular and neurologic function in patients with recurrent dislocation after total hip arthroplasty
The Journal of Arthroplasty, 1999
Twenty-two patients with recurrent dislocation after primary total hip arthroplasty (THA) were co... more Twenty-two patients with recurrent dislocation after primary total hip arthroplasty (THA) were compared with 43 randomly selected, stratified THA patients without dislocation with regard to radiographic cup position; body composition of bone, fat, and muscle (lean body mass) as determined by dual-energy x-ray absorptiometry; strength in abduction and adduction; range of motion; balance; and vibration sense. Balance and sensitivity to vibration were impaired in the patients with dislocation. No differences were found in any other variables except a subset of tall men in the dislocation group.
European Spine Journal, 2006
neurological deficits are usually described with a favourable long-term outcome [13, 14, 18, 20-2... more neurological deficits are usually described with a favourable long-term outcome [13, 14, 18, 20-22, 24, 26]. This could perhaps, at least partly, be explained by the modelling capacity in young children, reducing the deformity and restoring the height of the fractured vertebral body by growth [21], a capacity not found in adults . To our knowledge, no long-term studies exist which report both clinical and radiographic outcome decades after a thoracic or lumbar fracture sustained in
European Journal of Applied Physiology, 2008
program on muscle development in prepubertal girls.
Fractures of the Olecranon
Clinical Orthopaedics and Related Research, 2002
The incidence of olecranon fractures in adults and the long-term outcome of closed olecranon frac... more The incidence of olecranon fractures in adults and the long-term outcome of closed olecranon fractures in 45 women and 28 men (mean age, 54 and 36 years at the time of fracture, respectively), were examined at a mean of 19 years after the fracture. The uninjured elbows served as controls. Thirteen percent of the original fractures were displaced less than 2 mm, 65% more than 2 mm, and 22% were multifragmental. Primary treatment consisted of mobilization in 4%, application of a plaster cast in 12%, and open reduction and internal fixation in 84% of the elbows. The incidence of an isolated fracture of the olecranon in individuals older than 16 years was 1.15 per 10,000 person-years. Eighty-four percent of the 73 patients had no complaints at followup, 12% had occasional pain, and 4% had daily pain. Ninety-six percent had an excellent or good outcome. Elbow flexion and extension were reduced but most patients had no or only occasional subjective complaints. Radiographic signs of degenerative changes were found in more than 50% of the formerly fractured elbows, which was more than in the uninjured (11%). Radiographic signs of osteoarthritis were found in 6% of the formerly fractured elbows versus zero percent in the uninjured, of which only two patients had a poor outcome. Isolated, closed fractures of the olecranon in adults have a favorable, long-term outcome.
Physical Activity Increases Bone Size in Prepubertal Boys and Bone Mass in Prepubertal Girls: A Combined Cross-Sectional and 3-Year Longitudinal Study
Calcified Tissue International, 2002
This study evaluates the effect on the skeleton of physical activity from age 9 to 16. In 42 girl... more This study evaluates the effect on the skeleton of physical activity from age 9 to 16. In 42 girls and 44 boys, bone mass and bone size were evaluated longitudinally by dual-energy X-ray absorptiometry (DXA) from ages 13 to 16. Physical activity from ages 9 to 13 was cross-sectionally evaluated at baseline (age 13). Girls with high physical activity from ages 9 to 13 at baseline had higher femoral neck bone mineral content (FN BMC; g) (P = 0.07), higher FN areal bone mineral density (FN aBMD; g/cm2), and higher FN volumetric BMD (FN vBMD; g/cm3) (both P &lt; 0.05) compared with girls of low activity. FN width (cm) and head aBMD (an unloaded region) showed no differences when comparing the two groups. Three years of further high and low activity (from ages 13 to 16) did not yield any increased differences between the two groups. Boys with high physical activity from ages 9 to 13, had at baseline higher FN BMC, FN aBMD, and FN width (all P &lt; 0.05) compared with boys with low activity. FN vBMD and head aBMD showed no differences when comparing the two groups. Three years of further high and low activity did not yield any increased differences between the two groups. We conclude that exercise may yield skeletal benefits before age 13, and that 3 years of continued high or low level activity up to age 16 did not yield any increased differences in bone size or bone mass in either girls or boys.
Calcified Tissue International, 1995
This cross-sectional study was done in order to ascertain whether there is a lifelong beneficial ... more This cross-sectional study was done in order to ascertain whether there is a lifelong beneficial effect on bone mineral density (BMD) of early, long-lasting, and intense physical exercise. Forty-eight male ex-weight lifters, mean age 64 years (range 50-79) participated. They had followed a training program of an average of 10 hours/week (range 4-20) for an average of 13 years (range 1-34). They had all retired from competitive sport an average of 30 years (range 7-50) ago. Sixty-six age-matched volunteers served as controls. The bone mineral density (BMD, areal density, g/cm 2) in the total body, spine, and hips and the fat content and lean body mass were measured with the LUNAR DPX bone mass scanner. In ex-weight lifters 50-64 years of age, the BMD was greater than in controls. After 65 years, no difference was found between the former weight lifters and their controls.
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Papers by Magnus K Karlsson