Biomedical subjects

M K Karlsson

Publications and source records attributed to M K Karlsson.

At least 37 records · Page 2Linked to original sources

PubMed2001

Bone mass changes in weight-loaded and unloaded skeletal regions following a fracture of the hip.

Higher bone mineral density (BMD) has been reported in weight-loaded skeletal regions and lower BMD in unloaded regions in active athletes compared with controls. These discrepancies remain the first decades after cessation of active careers in former athletes with no remaining discrepancies found after age 65 years compared with age- and gender-matched controls. Physical activity is reduced after a hip fracture and BMD decreases in weight-loaded skeletal regions following the injury. If BMD increases in unloaded regions following a fracture of the hip it is not known. A BMD increase in an unloaded region would support the hypothesis of discrepancies in BMD response to physical activity in loaded and unloaded skeletal regions. BMD (g/cm2) was measured longitudinally using dual X-ray absorptiometry (DXA) in 32 women, mean age 77 years (range 57-90) and 12 men, mean age 74 years (range 53-89) with a hip fracture, the upper part of the skull representing an unloaded skeletal region, the arms a partly loaded region, and the femoral neck a weight-loaded region. Measurements (mean) were done in 11 days, 5 months, and 13 months after the hip fracture. Data are presented as mean +/- SEM. BMD increased in the upper part of the skull by 1.9%+/-0.8% the first 5 months and 3.7%+/-0.9% the first 13 months after the fracture (P < 0.05 and P < 0.001, respectively). BMD did not change in the arms but decreased in the nonfractured femoral neck by 4.7%+/-1.8% the first 5 months and 4.5%+/-1.7% the first 13 months after the fracture (both P < 0.01, respectively). In summary, in this longitudinal study, BMD increased in an unloaded skeletal region and decreased in a weight-loaded region following a hip fracture with reduced activity level, suggesting that loaded and unloaded skeletal regions confer different BMD response after changed activity level.

Absorptiometry, Photon↗

PubMed2001

The duration of exercise as a regulator of bone mass.

Exercise is associated with increased peak bone mineral density (BMD). To determine the relationship between the duration of exercise and BMD, we measured BMD of the axial and appendicular skeleton by dual-energy X-ray absorptiometry (DXA), and speed of sound (SOS), broadband attenuation (BUA), and stiffness index by quantitative ultrasound (QUS) of the calcaneus, in 67 active male national soccer players (mean age 23 years, range 17-35), which included 23 premier-league players exercising 12 h/week (range 8-18), 23 third-league players exercising 8 h/week (range 3-18), and 21 sixth-league players exercising 6 h/week (range 2-10). Results were compared with 24 sedentary age- and gender-matched controls and presented as mean +/- SEM. BMD was higher in all weight-bearing regions for the whole group relative to controls (BMD: total body 6.8 +/- 0.7%, leg 9.6 +/- 0.8%, lumbar spine 13.2 +/- 1.2%, femoral neck 12.7 +/- 1.2% [all p < 0.001]; calcaneus SOS 4.2 +/- 0.3%, BUA 8.7 +/- 1.5%, and stiffness index 24.2 +/- 2.0% [all p < 0.01]). No differences were found in head or arm BMD. There were no differences in BMD or QUS measurements when comparing soccer players exercising for different activity durations. Duration of activity correlated with BMD weight-loaded regions and with QUS, provided it was less <6 h/week (p < 0.01 respectively), but not when exercising more frequently. Femoral neck BMD increased by 3.3% across every hour increase in activity in those with 0-6 h of exercise/week and by 0.7% in those exercising more than this (p < 0.01). We conclude that, in national-league soccer, the BMD needed to attain a bone strength commensurate with that of duration of activity is achieved by 6 h of exercise per week. Beyond this, additional exercise confers no higher BMD. The skeleton adapts to the prevalent level of exercise intensity required and no further.

Absorptiometry, Photon↗

PubMed2001

Age, gender, and fragility fractures are associated with differences in quantitative ultrasound independent of bone mineral density.

Bone strength is determined by bone mineral density (BMD) and bone structure. Dual-energy X-ray absorptiometry (DXA) measures BMD. Whether quantitative ultrasound (qUS) measures a property of bone distinct from BMD is uncertain. To evaluate this, DXA and qUS were measured in 58 fracture patients and 428 controls. To study the independent effects of age and gender on qUS measurements and control for BMD by study design rather than statistical methods, subgroups from the normative database were created and intentionally matched by the same femoral neck (FN) BMD. Speed of sound (SOS; m/sec), broadband ultrasound attenuation (BUA; dB/MHz), and stiffness index (SI) were then compared in individuals matched by FN BMD but differing in age, gender, and presence or absence of fractures. The results are presented as percentage difference (mean +/- SD). Elderly women with the same FN BMD as young women had 1 +/- 2% lower SOS (p < 0.05), 8 +/- 15% lower SI (p < 0.05), and 4 +/- 9% lower BUA (p = 0.07). Elderly women with the same FN BMD as elderly men had 5 +/- 9% lower BUA (p < 0.05). Elderly men with the same FN BMD as young men had 1 +/- 2% lower SOS (p = 0.1), 5 +/- 14% lower SI (p = 0.2), and 1 +/- 9% lower BUA (n.s.). Young women with the same FN BMD as young men had 2 +/- 7% lower BUA (n.s.). Women with fragility fractures had 8 +/- 11% lower BUA (p < 0.001) and 13 +/- 22% lower SI (p < 0.01) than controls with no fractures matched by FN BMD, age, and gender. Men with fragility fractures had 13 +/- 12% lower BUA (p < 0.01) and 16 +/- 19% lower SI (p < 0.05) than controls with no fractures matched by FN BMD, age, and gender. Despite comparable femoral neck BMD, qUS measurements differed according to age, gender, and fracture status, suggesting that qUS may provide additional information independent of femoral neck BMD, such as differences in connectivity or other properties yet to be identified.

Absorptiometry, Photon↗

PubMed2001

Bone loss in relation to menopause: a prospective study during 16 years.

This prospective study evaluated bone loss in the peri- and postmenopausal period in 156 women followed from age 48 to 64 years. All women were premenopausal at the start of the study. Areal bone mineral density (g/cm(2)) was measured by single-photon absorptiometry (SPA) of the forearm at the 1 cm level (BMD 1 cm) and the 6 cm level (BMD 6 cm) every second year. Onset of menopause (MP) was determined according to the criteria of the World Health Organization (12 months of amenorrhea and elevated follicle-stimulating hormone). At the end of the study, 125 of 156 women (80%) remained. Bone mineral density (BMD) at age 48 years correlated with BMD at age 64 years within the respective region (r = 0.4-0.5, p < 0.001, respectively). There was no BMD loss in the premenopausal period. BMD loss was accelerated at menopause (MP) independent of chronological age. BMD loss was greater during the first 5 years following MP than during the following 6 years (BMD 1 cm 2.4% per year [1.0%-3.9%] vs. 0.4% per year [-0.3%-1.0%], p < 0.01). The quartile of women with late MP (>53.7 years) had greater bone loss during the first 5 years after MP than the quartile of women with early MP (<50.3 years) (p < 0.001). At age 64 years, BMD was no different when comparing the quartile of women with late MP vs. the quartile of women with early MP. Furthermore, there was no correlation between age at menopause and BMD at the age of 64. In summary, among women still menstruating at age 48 years, there was no measurable BMD loss in the premenopausal period. Independent of chronological age, BMD loss accelerated during MP. Rates of loss were highest in the early postmenopausal period. Independent of age at MP, premenopausal women with low age-specific BMD at age 48 years had an increased risk of sustaining low BMD at age 64 years also.

Female↗

PubMed2000

Exercise during growth and bone mineral density and fractures in old age.

If exercise is to be recommended during growth, benefits in bone mineral density (BMD) must be maintained in old age and shown to prevent fractures. Our cross-sectional study of soccer players suggests that a high BMD is no longer recorded after retirement and fracture frequency is no less than predicted in old age.

Aged↗

PubMed2000

Bone loss following tibial osteotomy: a model for evaluating post-traumatic osteopenia.

The reduced bone mineral density (BMD) found in patients with fractures may, in part, follow rather than precede the fracture. We studied the magnitude and reversibility of bone loss in the 15 months following osteotomy in 21 men and 5 women with localized medial arthritis of the knee. BMD (mean +/- SD), measured using dual-energy X-ray absorptiometry, decreased by a maximum of 35 +/- 21% in the mid-diaphysis of the affected tibia at 9 months after surgery (p < 0.001). At 15 months, reversal of bone loss in non-fractured bones was incomplete; the remaining deficit was 20 +/- 27% relative to baseline (p < 0.001). Maximum bone loss occurred at 9 months at the total body (5 +/- 2%), spine (15 +/- 17%) and at Ward's triangle of the proximal femur of the unoperated limb (10 +/- 17%) (all p < 0.01). In summary, post-traumatic bone loss is region-specific with incomplete reversibility, at least after about 15 months. Deficits in BMD in cross-sectional studies of patients with fractures, held to be responsible for the bone fragility, may, in part, follow rather than precede the fracture.

Absorptiometry, Photon↗

PubMed2000

Changes in bone mineral, lean body mass and fat content as measured by dual energy X-ray absorptiometry: a longitudinal study.

Bone mineral density (BMD) and soft tissue composition were measured by dual energy X-ray absorptiometry (DXA) 3-4 years apart in 273 men and women aged 23-90. We found different rates of BMD loss in different skeletal regions. There were also different rates of BMD loss in different regions within the hip. Average rates of loss for male subjects 50 years of age and above for BMD total body were 0.1%/year and for femoral neck 1.5%/year, whereas lumbar spine (L2-L4) increased by 0.4%/year. Average rates of loss for female subjects 50 years of age and above for BMD total body were 0.0%/year, femoral neck 0.9%/year, and lumbar spine (L2-L4) 0.1%/year.

Absorptiometry, Photon↗

PubMed2000

Bone size and volumetric density in women with anorexia nervosa receiving estrogen replacement therapy and in women recovered from anorexia nervosa.

Anorexia nervosa is associated with bone loss during adulthood, but may also delay skeletal growth and mineral accrual during growth. We asked the following questions. 1) Is anorexia nervosa associated with reduced bone size and reduced volumetric bone mineral density (vBMD)? 2) Is estrogen replacement therapy (ERT) or recovery from anorexia nervosa associated with normal bone size and vBMD? Using dual-energy x-ray absorptiometry, we measured bone size and vBMD of the third lumbar vertebra and femoral neck in a cross-sectional study of 161 female patients: 77 with untreated anorexia nervosa, 58 with anorexia nervosa receiving ERT, 26 recovered from anorexia nervosa, and 205 healthy age-matched controls. Results were expressed as the SD or z-score (mean +/- SEM). Deficits in vertebral body and femoral neck width in untreated women were -1.0 +/- 0.1 and -0.3 +/- 0.1 SD (P < 0.001 and P < 0.05, respectively). Deficits in bone width were less in the ERT-treated women than in untreated women at the vertebral body (-0.6 +/- 0.1 SD; P < 0.001), but not at the femoral neck (-0.4 +/- 0.2 SD; P < 0.05). There were no significant deficits in vertebral body and femoral neck width in recovered women (both -0.3 +/- 0.2 SD; P = NS). In untreated women, vertebral and femoral neck vBMD were -1.6 +/- 0.1 and -1.1 +/- 0.1 SD, respectively (both P < 0.001), less severely reduced in ERT-treated women (-1.2 +/- 0.2 and -0.6 +/- 0.2 SD, respectively; both P < 0.001), and least reduced in recovered women (-0.6 +/- 0.1 and -0.5 +/- 0.2 SD; P < 0.01 and P < 0.05, respectively). After adjusting for differences in fat and lean mass, vertebral body and femoral neck width were no longer reduced in untreated, ERT-treated, and recovered women. Adjustment for body composition had little effect on group difference in vBMD. Bone fragility in anorexia nervosa is due to reduced bone size and reduced vBMD. Although causality cannot be inferred in cross-sectional studies, the data are consistent with the view that malnutrition may contribute to reduced bone size, whereas estrogen deficiency may reduce vBMD. The use of ERT early in disease is a reasonable component of management if the chance of recovery appears remote.

Absorptiometry, Photon↗

PubMed2000

Heterogeneity in the growth of the axial and appendicular skeleton in boys: implications for the pathogenesis of bone fragility in men.

Men with spine fractures have reduced vertebral body (VB) volume and volumetric bone mineral density (vBMD). Men with hip fractures have reduced femoral neck (FN) volume and vBMD, site-specific deficits that may have their origins in growth. To describe the tempo of growth in regional bone size, bone mineral content (BMC), and vBMD, we measured bone length, periosteal and endocortical diameters, BMC, and vBMD using dual-energy X-ray absorptiometry in 184 boys aged between 7 and 17 years. Before puberty, growth was more rapid in the legs than in the trunk. During puberty, leg growth slowed while trunk length accelerated. Bone size was more advanced than BMC in all regions, being approximately 70% and approximately 35% of their predicted peaks at 7 years of age, respectively. At 16 years of age, bone size had reached its adult peak while BMC was still 10% below its predicted peak. The legs accounted for 48%, whereas the spine accounted for 10%, of the 1878 g BMC accrued between 7 and 17 years. Peripubertal growth contributed (i) 55 % of the increase in leg length but 78% of the mineral accrued and (ii) 69% of the increase in spine length but 87% of the mineral accrued. Increased metacarpal and midfemoral cortical thickness was caused by respective periosteal expansion with minimal change in the endocortical diameter. Total femur and VB vBMD increased by 30-40% while size and BMC increased by 200-300%. Thus, growth builds a bigger but only slightly denser skeleton. We speculate that effect of disease or a risk factor during growth depends on the regions maturational stage at the time of exposure. The earlier growth of a regions size than mass, and the differing growth patterns from region to region, predispose to site-specific deficits in bone size, vBMD, or both. Regions further from their peak may be more severely affected by illness than those nearer completion of growth. Bone fragility in old age is likely to have its foundations partly established during growth.

Absorptiometry, Photon↗

PubMed2000

On exposure to anorexia nervosa, the temporal variation in axial and appendicular skeletal development predisposes to site-specific deficits in bone size and density: a cross-sectional study.

Skeletal development is heterogeneous. Throughout growth, bone size is more maturationally advanced than the mineral being accrued within its periosteal envelope; before puberty, appendicular growth is more rapid than axial growth; during puberty, appendicular growth slows and axial growth accelerates. We studied women with differing age of onset of anorexia nervosa to determine whether this temporal heterogeneity in growth predisposed to the development of deficits in bone size and volumetric bone mineral density (vBMD), which varied by site and severity depending on the age at which anorexia nervosa occurred. Bone size and vBMD of the third lumbar vertebra and femoral neck were measured using dual-energy X-ray absorptiometry in 210 women aged 21 years (range, 12-40 years) with anorexia nervosa. Results were expressed as age-specific SDs (mean +/- SEM). Bone width depended on the age of onset of anorexia nervosa; when the onset of anorexia nervosa occurred (1) before 15 years of age, deficits in vertebral body and femoral neck width did not differ (-0.77+/-0.27 SD and -0.55+/-0.17 SD, respectively); (2) between 15 and 19 years of age, deficits in vertebral body width (-0.95+/-0.16 SD) were three times the deficits in femoral neck width (-0.28+/-0.14 SD; p < 0.05 comparing the deficits), (3) after 19 years of age, deficits in the vertebral body width (-0.49+/-0.26 SD; p = 0.05) were half that in women with earlier onset of anorexia nervosa. No deficit in bone width was observed at the femoral neck. Deficits in vBMD at the vertebra and femoral neck were independent of the age of onset of anorexia nervosa but increased as the duration of anorexia nervosa increased, being about 0.5 SD lower at the vertebra than femoral neck. We infer that the maturational development of a region at the time of exposure to disease, and disease duration, determine the site, magnitude, and type of trait deficit in anorexia nervosa. Bone fragility due to reduced bone size and reduced vBMD in adulthood is partly established during growth.

Adolescent↗

PubMed1999

Complications and outcome in open carpal tunnel release. A 6-year follow-up in 92 patients.

In this retrospective study, 92 patients (83% attendance rate) were examined 6 years after open carpal tunnel release. A questionnaire was answered by the patient and a physical examination was made by an independent observer. Five complications were found, of which 4 were early postoperative problems and one was a major complication with long-term disability. In one third of the patients numerous complaints were noted even after six years. Recurrences were found in 9 cases. No lacerations of nerves, tendons or vessels were seen and no patient developed reflex sympathetic dystrophy. The overall subjective outcome showed that 91% of the patients were free of symptoms or improved. The grip strength at follow-up was reduced, if the symptoms had been present for more than 12 months, as compared to less than 12 months, (p = 0.009) and when associated, unspecific brachialgia had been present (p = 0.02). No differences were found in conjunction with the operating surgeon being either an orthopaedic resident or a specialist in hand surgery. In conclusion, open carpal tunnel release had a subjectively favourable outcome, but due to complications and postoperative complaints, further investigations into alternative techniques seem necessary.

Adult↗

PubMed1998

Bone mineral density assessed by quantitative ultrasound and dual energy X-ray absorptiometry. Normative data in Malmö, Sweden.

We measured bone mineral density (BMD) in 128 men and 143 women, aged 22-90, by dual energy X-ray absorptiometry (DEXA) and quantitative ultrasound (QUS). We found reduced bone mineral density in relation to age as measured both by DEXA and QUS. There was a correlation between 0.28 and 0.52 in men and between 0.53 and 0.77 in women when comparing DEXA and QUS measurements. When including only persons with low bone mass, the correlation was less.

Absorptiometry, Photon↗

PubMed1997

Ligament lengthening compared with simple division of the transverse carpal ligament in the open treatment of carpal tunnel syndrome.

It has been suggested that the new (and controversial) endoscopic techniques are more successful than standard operation for the preservation of the ligamentous pulley function across the carpal tunnel and for the separation of the gliding structures from the subcutaneous tissues after release of the carpal ligament in carpal tunnel syndrome. We therefore decided to study the possible importance of preserving the continuity of the carpal ligament by doing an open lengthening of the ligament. This retrospective, unrandomised study included 99 patients with carpal tunnel syndrome who underwent open release of the carpal tunnel with or without a simultaneous lengthening of the transverse carpal ligament. The duration of follow up ranged from 4-8 years. The group who had the ligament lengthened had significantly longer sick leave (p < 0.01) than the group who had transverse ligament section alone. There were no advantages to reconstruction of the transverse ligament.

Adult↗

PubMed1997

Remodeling of the spinal canal deformed by trauma.

Computed tomography (CT) examinations and functional scores were evaluated in 28 patients with thoracolumbar fractures with intraspinal fragments, of whom 20 underwent operation. The cross-sectional area and the sagittal and frontal diameters of the spinal canal were measured after the injury, postoperatively, and at follow-up (mean, 6 years). The operative reduction significantly increased both diameter and area of the spinal canal. During follow-up, a further significant increase of the sagittal diameter and the area was noted, in both surgically and conservatively treated patients. There was no difference in remodeling between the groups. Six patients in the surgically treated group had neurologic deficits at admission, five had improved, and one remained unchanged at follow-up. The presence or absence of intraspinal fragments should not influence the treatment strategy per se in cases without neurologic signs.

Adolescent↗

PubMed1996

Bone mineral density in athletes during and after career: a comparison between loaded and unloaded skeletal regions.

Bone mineral density (BMD) was measured in the upper part of the skull, the femoral neck, and the total body by dual energy X-ray absorptiometry in 56 male and 33 female active athletes, 18-40 years of age, together with 64 male ex-weight lifters, 35-79 years of age. The active athletes were compared with 41 male and 54 female controls, the ex-weight lifters with 133 male controls. The purpose of the study was to see if BMD in the upper part of the skull, a region virtually unaffected by physical load, is different in athletes and controls. The male athletes had a 3% higher BMD for the total body and 12% for the hip, whereas the BMD for the upper part of the skull was 10% lower than controls. Corresponding BMD values for the female athletes were 4% higher for total body and 10% for the femoral neck, and the upper part of the skull was 7% lower than in controls. After 65 years of age there was no difference in BMD comparing ex-weightlifters and controls. Using a constructed ratio BMD total body to BMD upper part of the skull, the ex-weight lifters had 10% higher values also after age 65. It appears that bone mass is higher in weight-loaded areas and lower in an unloaded region, such as the upper part of the skull, in exercising athletes. After cessation of the active career, the bone mass approaches that of the controls and after 65 years of age, no difference was found comparing ex-weight lifters and controls. Due to the apparent bone mass shift from unloaded skeletal regions to loaded skeletal regions that seems to take place in active athletes, the constructed ratio, BMD total body to BMD upper part of the skull, seems to discriminate the influence on the skeleton in a more sensitive way than measuring the BMD in defined skeletal regions on their own. By using this constructed ratio, the influence on bone mass of physical exercise early in life is also detectable at older ages.

Adult↗

PubMed1995

Indicators of bone formation in weight lifters.

Physical activity has been suggested to be one of the determinants of bone turnover and to prevent age-related bone loss. To examine this we measured the serum levels of osteocalcin (bone Gla-protein, BGP), C-terminal procollagen peptide (PICP), serum alkaline phosphatase, bone-specific alkaline phosphatase, and S-calcium as indices of bone formation in 19 actively performing and 15 ex-lifters. All were nationally or internationally ranked male athletes. Their values were compared with those from 38 age- and gender-matched controls. Actively performing weight lifters had 35% higher (P < 0.05) serum concentration of osteocalcin than the controls. The ex-lifters did not differ from the age-matched controls. Also serum calcium was elevated in active lifters (6%) (P < 0.01) but not in ex-lifters. No difference was found for serum-ALP, B-ALP, or PICP in either of the groups. Our study indicates that in addition to an already documented and well-known higher bone mineral density in heavily exercising athletes, they have an indication of higher bone formation as measured by biochemical markers. In athletes who have retired from competitional training, however, the bone formation does not differ from that of more sedentary controls.

Adult↗

PubMed1995

Is bone mineral density advantage maintained long-term in previous weight lifters?

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/cm2) 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.

Absorptiometry, Photon↗

PubMed1993

Bone mineral density in weight lifters.

The effect of intense physical training on the bone mineral content (BMC) and soft tissue composition, and the development of these values after cessation of the active career, was studied in 40 nationally or internationally ranked male weight lifters. Nineteen were active and 21 had retired from competition sports. Fifty-two age- and sex-matched nonweight lifters served as controls. The bone mineral density (BMD) in total body, spine, hip, and proximal tibial metaphysis was measured with a Lunar Dual-energy X-ray absorptiometry (DXA) apparatus and the BMD of the distal forearm was measured with single photon absorptiometry (SPA). Seventeen of the lifters had been measured earlier with SPA in the forearm and 23 in the tibial condyle during their active career in 1975. The BMD was significantly higher in the weight lifters compared with the controls (10% in the total body P < 0.001, 12% in the trochanteric region P < 0.001, and 13% in the lumbar spine P < 0.001). All measured regions except the head showed significant higher bone mass in the weight lifters compared with the controls. In older lifters, the difference from the controls seemed to increase in total body and lumbar vertebrae (BMD), but remained unchanged in the hip. Significant correlation was found between the SPA measurements in 1975 and the corresponding measurements 15 years later in both the forearm (r = 0.51, P < 0.05 at the 1-cm level and r = 0.87, P < 0.001 at the 6-cm level) and in the tibial condyle (r = 0.61, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗