Biomedical subjects

R Lorentzon

Publications and source records attributed to R Lorentzon.

At least 37 records · Page 2Linked to original sources

PubMed2000

Osteocalcin gene polymorphism is related to bone density in healthy adolescent females.

Recently a polymorphism was found in the human osteocalcin gene, and its association with bone mass was investigated in healthy postmenopausal Japanese women. The osteocalcin gene allelic variant HH was found to be overrepresented in women with osteopenia. The purpose of this study was to investigate whether the previously demonstrated polymorphism of the osteocalcin gene was related to bone mineral density (BMD; g/cm2) or osteopenia in a group of 97 healthy Caucasian adolescent females (aged 16.9 +/- 1.2 years, mean +/- SD). BMD of the left humerus, right femoral neck, lumbar spine and total body was measured using dual-energy X-ray absorptiometry. The relation between the allelic variants and bone density was analyzed as presence or absence of the H allele. Presence of the H allele was found to be related to a lower BMD of the humerus (0.97 vs 1.02, p = 0.03). There was also a strong tendency towards significance at the femoral neck (p = 0.06) and total body (p = 0.11). Using a multiple linear regression and including physical activity, weight, height and years since menarche, presence of the H allele was found to be an independent predictor of humerus BMD (beta = -0.21, p < 0.05) and femoral neck BMD (beta = -0.23, p < 0.01). Using logistic regression, presence of the H allele was also independently associated with a 4.5 times increased risk of osteopenia (p = 0.03) in the whole group. Osteopenia was defined as at least 1 SD lower bone density than the mean for the whole group of at least one of the BMD sites measured. We have demonstrated that the osteocalcin HindIII genotype is independently related to bone density in healthy adolescent females. The present study also suggests that presence of the H allele is predictive of osteopenia at an early age.

Adolescent↗

PubMed2000

Bone mass in female cross-country skiers: relationship between muscle strength and different BMD sites.

In this cross-sectional study, bone mass and muscle strength of the thigh were investigated in 16 Caucasian female cross-country skiers, age 16.2 +/- 0.3 years, that had been ski-training for 6.4 +/- 1.8 years (range 3-9 years) and were now training for 6.3 +/- 2.4 hours/week (range 3-12 hours). They were compared with 16 nonactive females, age 16.4 +/- 0.7 years. The groups were matched according to age, weight, height, and pubertal status. Areal bone mineral density (BMD) was measured using dual energy X-ray absorptiometry, in the total body, head, both total humerus and humerus diaphyses, spine, and in the right femoral neck, greater trochanter, femoral diaphysis, distal femur, proximal tibia, and tibia diaphysis. Bone mineral apparent density (BMAD) was also calculated for the femoral neck and humerus diaphyses. Isokinetic muscle strength of the quadricep and hamstring muscles was measured in an isokinetic dynamometer. Compared with the controls, the cross-country skiing group had significantly higher BMD in the right whole humerus (6.9%), left whole humerus (9.2%), left humerus diaphysis (8.1%), femoral neck (8.9%), greater trochanter (9.3%), femur diaphysis (7.6%), and BMAD of the femoral neck (+19.4%). In the nonactive group there were significant side-to-side differences in BMD of the whole humeri, humerus diaphyses, and BMAD of the humerus diaphyses (3.1%, 5.4%, and 8.8% higher in the right arm, respectively). No such differences were found in the cross-country skiing group. Lean body mass was significantly higher in the cross-country skiers (21.7%), and fat mass (-25.5%) and body fat percent (-28.0%) were significantly lower compared with the nonactive group. There were, however, no significant differences in concentric peak torque of the thigh muscles between the two groups. Stepwise regression analyses revealed that BMI was the best predictor of several sites in the nonactive group. In the cross-country group, on the other hand, muscle strength was a strong predictor of BMD, both at adjacent and more distant BMD sites. In conclusion, it seems that this type of endurance training is associated with a site-specific higher bone mass that may be associated with the type and magnitude of loading during off-season and during the main sports activity, cross-country skiing.

Absorptiometry, Photon↗

PubMed2000

Effect of high impact activity on bone mass and size in adolescent females: A comparative study between two different types of sports.

The purpose of this cross-sectional study was to investigate the influence of two different types of weight-bearing activity, muscle strength, and body composition on bone mineral density (BMD), bone mineral content (BMC), and bone area in three different groups of late adolescent girls. The first group consisted of 10 females participating in competitive rope-skipping (age 17.8 +/- 0.8 years) training for 6.7 +/- 3.1 hours/week; the second group consisted of 15 soccer players (age 17.4 +/- 0.8 years) training for 6.1 +/- 2.0 hours/week; and the third group consisted of 25 controls (age 17.6 +/- 0.8 years) with physical activity of 0.9 +/- 1.1 hours/week. The groups were matched for age, height, and weight. BMD (g/cm(2)), BMC (g), and bone area (cm(2)) of the total body, lumbar spine, hip, total femur, distal femur, diaphyses of femur and tibia, proximal tibia, and humerus were measured using dual-energy X-ray absorptiometry (DXA). Bone density was also assessed in the radial forearm site of the dominant limb in the rope skippers and in 10 matched controls. The rope skippers had 22% higher BMD at the ultradistal site (P < 0.01). Both high-activity groups had significantly higher BMD (P < 0.05) at most loaded sites compared with the control group. When adjusting for differences in lean mass and starting age of sport-specific training between the activity groups, the rope-skipping group had a higher BMD of the total body, lumbar spine, and right humerus compared with the soccer group. They also had a significantly higher bone area of the total body, total femur, and the proximal femur than both other groups, and a significantly higher bone area of the tibia diaphysis, compared with the soccer group. In a multivariate analysis among all subjects (n = 50), all BMD sites, except the femur diaphysis, distal femur, and proximal tibia, were significantly related to type of physical activity (beta = 0.25-0.43, P < 0.05). The bone area values at different sites were strongly related to muscle strength and parameters related to body size [height, weight, lean mass, fat mass, and body mass index (BMI)]. In conclusion, it appears that in late adolescent women, weight-bearing activities are an important determinant for bone density, and high impact activities such as jumping also seem to be associated with a modification of the bone geometry (hence, the bone width) at the loaded sites.

Absorptiometry, Photon↗

PubMed2000

Bone mass and muscle strength in young female soccer players.

In this cross-sectional study, bone mass and muscle strength of the thigh were investigated in 51 female soccer players, age 16.3 +/- 0. 3 years, who had been playing soccer for 8.1 +/- 2.1 years and were at the time of the study in soccer training for 5.0 +/- 1.7 hours/week. They were compared with 41 nonactive females, age 16.2 +/- 1.3 years. The groups were matched according to age, weight, and height. Areal bone mineral density (BMD) was measured of the total body, head, lumbar spine, femoral neck, Ward's triangle, and the greater trochanter using dual energy X-ray absorptiometry (DXA). Isokinetic muscle strength of the quadriceps and hamstrings muscles was measured using an isokinetic dynamometer. Compared with the nonactives, the soccer players had significantly higher BMD of the total body (2.7%), lumbar spine (6.1%), the dominant and nondominant hip (all sites). The largest differences were found in the greater trochanter on both sides (dominant, 16.5%, nondominant, 14.8%). The soccer players had significantly higher concentric and eccentric peak torque of the thigh muscles. In the soccer group, there was only a positive association between thigh muscle strength and BMD of the adjacent hip, and in the nonactive group there were several positive associations between muscle strength and BMD. However, when adjusting for the variation in weight and height all these associations became nonsignificant. Using multiple linear regression, the type of activity (soccer player, nonactive) independently predicted BMD of all dominant hip sites (beta = 0.32-0.48, P < 0.01). No other variable was found to independently predict BMD of any site. In the younger subjects (</=16 years) only BMD of the greater trochanter was significantly higher in the soccer players. In the older subjects (>16 years) the soccer players had significantly higher BMD in all measured sites except for the nonweight-bearing head. The differences in muscle strength between soccer players and nonactives were already seen in the young age group. In conclusion, girls who train and play soccer in adolescence have a higher bone mass in the hip and lumbar spine, and a higher muscle strength of the thigh compared with nonactive controls, indicating a site-specific skeletal response of weight-bearing and impact-loadng acting on the skeleton. The differences in bone mass were already apparent in early adolescence, but became more pronounced in late adolescence, probably explained by a longer exposure to soccer training with time. Our results also indicate that muscle strength in itself might not be of decisive importance for bone mass in the hip of adolescent females.

Absorptiometry, Photon↗

PubMed2000

Bone mineral density and muscle strength in female ice hockey players.

The purpose of this study was to investigate bone mineral density (BMD) at different sites in female ice hockey players as well as to study the relationship between BMD, muscle strength, and body composition parameters. The study group consisted of 14 female ice hockey players (age 22.2 +/- 4.3 years) which was compared with 14 inactive females (age 21.5 +/- 3.8 years). The two groups were matched for age and weight. Areal bone mineral density was measured in total body, head, lumbar spine, femoral neck, Ward's triangle and the trochanter, using dual energy X-ray absorptiometry. Body composition parameters were derived from the total body scan. Isokinetic concentric peak torque of the left quadriceps and hamstrings muscles was measured using an isokinetic dynamometer. Compared to the inactive group, the ice hockey players had significantly higher BMD of all of the bone sites measured, except for the head, (total body 6.9%, head -2.6%, lumbar spine 8.9%, femoral neck 17.6%, Ward's triangle 20.4%, and trochanter 21.7%). The hockey players also had significantly higher peak torque in the quadriceps and hamstrings muscles. In the ice hockey group, a significant positive correlation was found between BMD of the femoral neck and hamstrings peak torque at 225 degreesisecond (r = 0.67, P < 0.01). In the inactive group, significant positive correlations were found between BMD and peak torque in the hamstrings muscles (90 degrees/second: r = 0.6-0.8, P<0.05 (total body, trochanter) and P<0.01 (spine, neck), 225 degrees/second: r = 0.5-0.8, P<0.05 (total body, Ward's triangle, trochanter) and P< 0,01 (spine, neck)). In the inactive group significant positive correlations was also found between lean body mass and BMD of the trochanter (r = 0.58, P < 0.05). In young females it appears that training and playing ice hockey might influence BMD and muscle strength in a positive direction. The correlation between BMD and muscle strength seems to weaken with increased exercise level.

Absorptiometry, Photon↗

PubMed2000

In vivo investigation of ECRB tendons with microdialysis technique--no signs of inflammation but high amounts of glutamate in tennis elbow.

We used the microdialysis technique to study concentrations of substances in the extensor carpi radialis brevis (ECRB) tendon in patients with tennis elbow. In 4 patients (mean age 41 years, 3 men) with a long duration of localized pain at the ECRB muscle origin, and in 4 controls (mean age 36 years, 2 men) with no history of elbow pain, a standard microdialysis catheter was inserted into the ECRB tendon under local anesthesia. The local concentrations of the neurotransmitter glutamate and prostaglandin E2 (PGE2) were recorded under resting conditions. Samplings were done every 15 minutes during a 2-hour period. We found higher mean concentrations of glutamate in ECRB tendons from patients with tennis elbow than in tendons from controls (215 vs. 69 micromoL/L, p < 0.001). There were no significant differences in the mean concentrations of PGE2 (74 vs. 86 pg/mL). In conclusion, in situ microdialysis can be used to study certain metabolic events in the ECRB tendon of the elbow. Our findings indicate involvement of the excitatory neurotransmitter glutamate, but no biochemical signs of inflammation (normal PGE2 levels) in ECRB tendons from patients with tennis elbow.

Adult↗

PubMed2000

Vitamin D receptor gene polymorphism is associated with birth height, growth to adolescence, and adult stature in healthy caucasian men: a cross-sectional and longitudinal study.

Vitamin D receptor (VDR) polymorphism has been associated with bone mineral density (BMD), but recent data indicate association to parameters of body constitution and growth. We investigated VDR gene polymorphism, defined by BsmI and TaqI, in 90 healthy Caucasian males and any relation with parameters of body constitution at birth, and to parameters of body constitution, BMD and bone area, at age 16.9 +/- 0.3 yr (mean +/- SD) and at age 19.2 +/- 0.7. Using PCR and the restriction enzyme BsmI and TaqI, the allelic variants BB, Bb, and bb, and TT, Tt, and tt were identified. Height (cm) and weight (kg) were measured using standardized equipment, and BMD of the total body, lumbar spine, and femoral neck, and bone area (cm2) of the total body, humerus, femur was measured using dual-energy x-ray absorptiometry. BsmI and TaqI genotypes were related in 89 of the 90 cases; hence, the same associations were found for both genotypes. Boys with the BB genotype were shorter at birth (P = 0.01) and grew less from birth to age 16.9 +/- 0.3 (P = 0.01) than their Bb and bb counterparts. Both during puberty (age 16.9 +/- 0.3) and after puberty (age 19.3 +/- 0.7), the BB boys were shorter (P = 0.005-0.008) and had lower bone area of the humerus, femur, and total body (P < 0.05) than the Bb and bb boys. The allelic variants were not related to BMD at any site. A prediction model including parental height, birth height, birth weight, and VDR alleles could predict up to 39% of the total variation in adult height in our population. The VDR allelic variants alone contributed to 8% of the total variation.

Adolescent↗

PubMed2000

Interleukin-6 gene polymorphism is related to bone mineral density during and after puberty in healthy white males: a cross-sectional and longitudinal study.

Bone mineral density (BMD) is under strong genetic control and is the major determinant of fracture risk. The cytokine interleukin-6 (IL-6) is an important regulator of bone metabolism and is involved in mediating the effects of androgens and estrogens on bone. Recently, a G/C polymorphism in position -174 of the IL-6 gene promoter was found. We investigated this genetic polymorphism in relation to BMD during late puberty and to peak bone mass, in healthy white males. We identified the IL-6 genotypes (GG, GC, and CC) in 90 boys, age 16.9 +/- 0.3 years (mean +/- SD), using polymerase chain reaction (PCR). BMD (g/cm2) at the femoral neck, lumbar spine, and total body was measured using dual energy X-ray absorptiometry. The volumetric BMD (vBMD; mg/cm3) of the lumbar spine was estimated. Differences in BMD in relation to the genotypes were calculated using analysis of variance (ANOVA). Subjects with the CC genotype had 7.9% higher BMD of the femoral neck (p = 0.03), 7.0% higher BMD of the lumbar spine (p < 0.05), and 7.6% higher vBMD of the lumbar spine (p = 0.04), compared with their GG counterparts. Using multiple regression, the IL-6 genotypes were independently related to total body BMD (CC > GG; p = 0.03), humerus BMD (CC > GG; p < 0.05), neck BMD (CC > GG; p = 0.01), spine BMD (CC > GG; p = 0.01), and spine vBMD (CC > GG; p = 0.008). At age 19.3 +/- 0.7 years (mean +/- SD; 88 men) the IL-6 genotypes were still independent predictors for total body BMD (CC > GG; p = 0.03), humerus BMD (CC > GG; p = 0.03), spine BMD (CC > GG; p = 0.02), and spine vBMD (CC > GG; p = 0.003), while the IL-6 genotypes were not related to the increase in bone density seen after 2 years. We have shown that polymorphism of the IL-6 gene is an independent predictor of BMD during late puberty and of peak bone mass in healthy white men.

Adolescent↗

PubMed2000

Chronic Achilles tendinosis: recommendations for treatment and prevention.

Chronic Achilles tendinosis is a condition with an unknown aetiology and pathogenesis that is often, but not always, associated with pain during loading of the Achilles tendon. Histologically, there are no inflammatory cells, but increased amounts of interfibrillar glycosaminoglycans and changes in the collagen fibre structure and arrangement are seen. In situ microdialysis has confirmed the absence of inflammation. It is a condition that is most often seen among recreational male runners aged between 35 and 45 years, and it is most often considered to be associated with overuse. However, this condition is also seen in patients with a sedentary lifestyle. Chronic Achilles tendinosis is considered a troublesome injury to treat. Nonsurgical treatment most often includes a combination of rest, NSAIDs, correction of malalignments, and stretching and strengthening exercises, but there is sparse scientific evidence supporting the use of most proposed treatment regimens. It has been stated that, in general, nonsurgical treatment is not successful and surgical treatment is required in about 25% of patients. However, in a recent prospective study, treatment with heavy load eccentric calf muscle training showed very promising results and may possibly reduce the need for surgical treatment of tendinosis located in the midportion of the Achilles tendon. The short term results after surgical treatment are frequently very good, but in the few studies with long term follow-up there are signs of a possible deterioration with time. Calf muscle strength takes a long time to recover and, furthermore, a prolonged progressive calcaneal bone loss has been shown on the operated side up to 1 year after surgical treatment.

Achilles Tendon↗

PubMed1999

Bone mass in the calcaneus after heavy loaded eccentric calf-muscle training in recreational athletes with chronic achilles tendinosis.

In an ongoing prospective study of 14 recreational athletes (12 males and 2 females, mean age 44.2 +/- 7.1 years) with unilateral chronic Achilles tendinosis, we investigated the effect of treatment with heavy-loaded eccentric calf-muscle training. Pain during activity (recorded on a VAS scale) and isokinetic concentric and eccentric calf-muscle strength (peak torque at 90 degrees /second and 225 degrees /second) on the injured and noninjured side were evaluated. In this group of patients, we examined areal bone mineral density (BMD) of the calcaneus after 9 months (range 6-14 months) of training. BMD of the injured side (subjected to heavy-loaded eccentric training) was compared with BMD of the noninjured side. Before onset of heavy-loaded eccentric training, all patients had Achilles tendon pain which prohibited running activity, and significantly lower concentric and eccentric plantar flexion peak torque on the injured compared with the noninjured side. The training program consisted of 12 weeks of daily, heavy-loaded, eccentric calf-muscle training; thereafter the training was continued for 2-3 days/week. The clinical results were excellent-all 14 patients were back at their preinjury level with full running activity at the 3 month follow-up. The concentric and eccentric plantar flexion peak torque had increased significantly and did not significantly differ from the noninjured side at the 3 and 9 month follow-up. There were no significant side-to-side differences in BMD of the calcaneus. There was no significant relationship between BMD of the calcaneus and calf-muscle strength. As a comparison group, we used 10 recreational athletes (5 males and 5 females) mean age 40.9 years (range 26-55 years), who were selected for surgical treatment of chronic Achilles tendinosis localized at the 2-6 cm level. Their duration of symptoms and severity of disease were the same as in the experimental group. There were no significant side-to-side differences in BMD of the calcaneus preoperatively, but 12 months postoperatively BMD of the calcaneus was 16.4% lower at the injured side compared with the noninjured side. Heavy-loaded eccentric calf-muscle training resulted in a fast recovery in all patients, equaled the side-to-side differences in muscle strength, and was not associated with side-to-side differences in BMD of the calcaneus. In this group of middle-aged recreational athletes, BMD of the calcaneus was not related to calf-muscle strength.

Achilles Tendon↗

PubMed1999

Treatment of tear of the anterior cruciate ligament combined with localised deep cartilage defects in the knee with ligament reconstruction and autologous periosteum transplantation.

An acute tear of the anterior cruciate ligament (ACL) is frequently associated with injuries to the joint cartilage and subchondral bone. These injuries may progress to deep cartilage defects, causing disabling pain, and represent a therapeutic challenge in patients with the combination instability and pain. At our clinic we treat patients with the combined injury with simultaneous ACL reconstruction and autologous periosteum transplantation of the cartilage defect. This report describes the technique for periosteum transplantation of full-thickness cartilage defects in the medial femoral condyle. Our clinical report includes the first 7 patients (6 men and 1 woman, mean age 29.1 years at operation) who have been followed for 2 years or longer of 14 consecutive patients (12 men and 2 women). All patients had suffered a total tear of the ACL and a full-thickness defect of the cartilage at the medial femoral condyle. The cartilage defects had a mean area of 7.3 cm2 (range 1.0-13.5 cm2). All patients had disabling instability and medial knee pain when walking. The anterior cruciate ligament was reconstructed with a bone-tendon-bone graft of the central third of the patellar ligament. After preparation of the cartilage lesion, the periosteum transplant was anchored to the underlying bone with suture anchors and fibrin glue. Postoperatively, these patients (n = 7) were initially treated with continuous passive motion, followed by active flexibility training and slowly progressing strength training and weight-bearing activities. At follow-up a mean of 31.3 months (range 24-38 months) later, 6 patients evidenced subjectively stable knees, no pain during rest or when walking, and had returned to not too heavy knee-loading work. One patient had a subjectively stable knee, but felt medial knee pain. Meticulous surgical technique and rigorous postoperative rehabilitation are probably of the greatest importance in this procedure. With the use of suture anchors and fibrin glue, the periosteum transplant can be well adapted to the condylar subchondral bone bed.

Adult↗

PubMed1999

Superior results with continuous passive motion compared to active motion after periosteal transplantation. A retrospective study of human patella cartilage defect treatment.

Fifty-seven consecutive patients (33 men and 24 women), with a mean age of 32 years (range 16-53 years), who suffered from an isolated full-thickness cartilage defect of the patella and disabling knee pain of long duration, were treated by autologous periosteal transplantation to the cartilage defect. The first 38 consecutive patients (group A) were postoperatively treated with continuous passive motion (CPM), and the next 19 consecutive patients (group B) were treated with active motion for the first 5 days postoperatively. In both groups, the initial regimens were followed by active motion, slowly progressive strength training, and slowly progressive weight bearing. In group A, after a mean follow-up of 51 months (range 33-92 months), 29 patients (76%) were graded as excellent or good, 7 patients (19%) were graded as fair, and 2 patients (5%) were graded as poor. In group B, after a mean follow-up of 21 months (range 14-28 months), 10 patients (53%) were graded as excellent or good, 6 patients (32%) were graded as fair, and 3 patients (15%) were graded as poor. Altogether, nine of the fair or poor cases (50%) were diagnosed with chondromalacia of the patella. Our results, after performing autologous periosteal transplantation in patients with full-thickness cartilage defects of the patella and disabling knee pain, are good if CPM is used postoperatively. The clinical results using active motion postoperatively are not acceptable, especially not in patients with chondromalacia of the patella.

Adult↗

PubMed1999

In situ microdialysis in tendon tissue: high levels of glutamate, but not prostaglandin E2 in chronic Achilles tendon pain.

This investigation was to our knowledge the first to use the microdialysis technique to study concentrations of substances in a human tendon. In four patients (mean age 40.7 years) with a painful nodule in the Achilles tendon (chronic Achilles tendinosis) and in five controls (mean age 37.2 years) with normal Achilles tendons (confirmed by ultrasonography) the local concentrations of glutamate and prostaglandin E2 were measured under resting conditions. A standard microdialysis catheter was inserted into the Achilles tendon under local anesthesia. Sampling was performed every 15 min over a 4-h period. The results showed significantly higher concentrations of glutamate in tendons with tendinosis than in normal tendons (196 +/- 59 vs. 48 +/- 27 mumol/l, P < 0.05), and there were no significant changes in glutamate concentration over the period of investigation. There were no significant differences in the mean concentrations of prostaglandin E2 (83 +/- 22 vs. 54 +/- 24 pg/ml) between tendons with tendinosis and normal tendons. In conclusion, in situ microdialysis appears a useful method to study certain metabolic events in tendon tissue. The higher concentrations of the excitatory neurotransmitter glutamate in Achilles tendons with a painful nodule may possibly be involved in the pain mechanism in this chronic condition. Furthermore, there were no signs of inflammation in the tendons with painful nodules, as indicated by the normal prostaglandin E2 levels.

Achilles Tendon↗

PubMed1999

Progressive hemiosteoporosis on the paretic side and increased bone mineral density in the nonparetic arm the first year after severe stroke.

Fractures are a common and serious complication after stroke and the risk of hip fractures among stroke patients is 2 to 4 times greater than among other elderly people. The aim of this study was to investigate prospectively the change in bone mineral density (BMD) after severe stroke and to study the association between motor impairment, disability and the development of hemiosteoporosis. The study comprised 24 stroke patients, with no persistent paresis from previous strokes or previous osteoporotic fractures, included 1 month after stroke onset. BMD, motor function, ambulation and activities of daily living (ADL) were assessed at 1, 4, 7 and 12 months after stroke onset. At inclusion, the patients' BMD was normal for their age. During the study, there was a significant loss of BMD in the total body (-2.0%; p < 0.05), but not in the head or spine. BMD differed significantly between the paretic and the non-paretic arm at inclusion (-4.8%; p < 0.001). Decrease in BMD was most pronounced in the affected humerus (-17.4%; p < 0.001) and proximal femur (-12.2%; p < 0.01). BMD decreased significantly in both lower extremities during follow-up, but the losses were more pronounced on the paretic side (p < 0.01). In the nonaffected ultradistal radius there was a significant increase in BMD from inclusion to the end of the study (+5.8%; p < 0.01). There was no pattern in the bone losses correlating with presumptive risk factors for hemiosteoporosis such as motor function, ability to perform ADL or ambulation. Two patients had fractures at follow-up, both on the paretic side. Loss of bone mineral density in the paretic extremities is thus pronounced and progressive during the first year after stroke, indicating that loss of BMD is probably an important risk factor for post-stroke fractures. Surprisingly, BMD in the nonaffected arm increased significantly during the first year after stroke, most likely due to increased physical activity, and perhaps a redistribution of bone minerals from the paretic extremities.

Aged↗

PubMed1999

Influence of heredity and environment on bone density in adolescent boys: a parent-offspring study.

The purpose of the present parent-offspring study was to investigate the influence of heredity and environment on bone density in young men. Another aim was to discover whether the same genetic factors influence bone mass, lean mass and muscle strength. Fifty families including a father, mother and one son were investigated. The mothers (aged 44.5 +/- 4.4 years) and fathers (aged 47.1 +/- 4.4 years) generally had a sedentary lifestyle with little physical activity. As a contrast, all but three of the sons (aged 17.0 +/- 0.4 years) were active in ice hockey training. Bone mineral density (BMD, g/cm2) of the total body, head, lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry. Muscle strength of the hamstrings and quadriceps muscles was also measured in the boys. BMD values of different sites in the fathers, mothers and sons were adjusted for weight, height, age, and any significant influence of environment. Heritability estimates were obtained as regression coefficients with the boys' adjusted BMD as dependent variable and the adjusted midparent bone density (father BMD + mother BMD/2) as independent variable. Accordingly, heritability explained 34-54% of the variation in the sons' BMD. Midparent BMD of several sites also predicted the boys' lean mass and quadriceps strength, and midparent-offspring differences in lean mass predicted midparent-offspring differences in BMD of the total body, head and spine (beta = 0.30-0.51, p < 0.05). The sons were found to have almost 30% higher femoral neck BMD than their fathers, and physical activity (hours/week) predicted BMD at several sites among the sons beta = 0.26-0.34, p < 0.05). In conclusion, heritability is a main determinant of the variance in BMD in young men. Based on the results we suggest that the same genetic factors may influence bone mass, lean mass and muscle strength by affecting body size. The present study also emphasizes the importance of physical activity for the development and maintenance of BMD in men.

Adolescent↗

PubMed1999

Low bone mass density at multiple skeletal sites, including the appendicular skeleton in amenorrheic runners.

The aim of this study was to investigate any difference in bone mass at different sites between female long-distance runners with amenorrhea and those with eumenorrhea. We compared 10 amenorrheic and 10 eumenorrheic athletes to determine whether athletes with amenorrhea have lower BMD in multiple skeletal regions, including weight-bearing lower limbs. The amenorrheic group had experienced menstrual dysfunction ranging from 3 to 43 months. As a further control group, 16 eumenorrheic soccer players were compared with the former two running groups regarding their BMD measurements. The two groups were matched for age, height, and amount of training. Areal bone mineral density (BMD) was measured and was found to be significantly lower in the total body, humerus, spine, lumbar spine, pelvis, femoral neck, trochanter, total femur, femur diaphysis, tibia diaphysis and in the nonweight-bearing head of the femur in the amenorrheic group. Body weight, BMI, fat mass, and body fat percent were significantly lower in the amenorrheic group. The differences in the BMD of the head, humerus, femoral neck, total femur, femur diaphysis, and tibia diaphysis disappeared when adjusted for body weight. Compared with the soccer group, the amenorrheic subjects had significantly lower BMD values at all sites except for the head, Ward's triangle, and femur diaphysis. Blood samples were obtained in the two running groups for analysis of osteocalcin, carboxy terminal telopeptide (ICTP), procollagen I (PICP), and estradiol. There were no significant differences between the groups but there was a strong tendency towards a lower estradiol level and a higher osteocalcin level in the amenorrheic group. A free estradiol index (FE2) was derived as the ratio of estradiol to sex hormone binding globulin (SHBG) and was significantly lower in the amenorrheic group. No difference in their daily intake of total energy, protein, carbohydrates, fiber, calcium, and vitamin D was observed. However, both groups showed a surprisingly low energy intake in relation to their training regimens. Stepwise regression analyses revealed that weight was the best predictor of spine BMD in both groups. Estradiol and FE2 were significant predictors of the BMD of the proximal femur in the eumenorrheic group, but did not predict any BMD site in the amenorrheic group. In conclusion, amenorrhea in athletic women affects trabecular and cortical bone in both axial and appendicular skeleton. However, some of the discrepancy can be explained by a lower body weight. Physical weight-bearing activity does not seem to completely compensate for the side effects of reduced estrogen levels even in weight-bearing bones in the lower extremity and spine.

Adolescent↗

PubMed1999

A comparison of bone mineral density and muscle strength in young male adults with different exercise level.

The aim of this study was to investigate any differences in bone mass at different sites between young adults subjected to a high physical activity and a group of young adults with a low level of physical activity. In addition, we compared the relationship among bone mass, muscle strength, and body constitution in these two groups. The reference group consisted of 20 men, age 24.6 +/- 2.3 years, not training for more than 3 hours per week. The ice hockey players consisted of 20 players, age 23.4 +/- 4.9 years, from an ice hockey team in the second highest national Swedish league, training for about 10 hours per week. The groups were matched according to age, height, and weight. Areal bone mineral density (BMD) was measured in total body, head, humerus, spine, pelvis, femur, femoral neck, Ward's triangle, trochanter, femur diaphysis, proximal tibia, and tibia diaphysis using dual energy X-ray absorptiometry. BMD was significantly higher in the total body (8.1%), humerus (11.4%), spine (12.7%), pelvis (12.4%), femoral neck (10.3%), femur (7.4%), proximal tibia (9.8%), and tibia diaphysis (7.5%) in the high activity group. Fat mass was significantly lower in the high activity group (18.7%). The high activity group also had a significantly higher lean body mass (5.4%) and a significantly higher isokinetic muscle strength of the quadriceps muscle compared with the reference group. In the reference group, there was a general strong independent relationship between muscle strength of the thigh and all BMD sites, except for the head, tibia diaphysis, and proximal tibia. Furthermore, in the same group, body mass index (BMI) independently predicted pelvis BMD. On the contrary, in the high activity group, muscle strength did not predict any BMD site at all. In the same group, body constitutional parameters (weight, height, and fat mass) independently predicted pelvis BMD, and BMI was shown to be an independent predictor of humerus BMD. The differences in BMD between the groups seem to be site-specific and may be associated with the type and magnitude of loading during off season training and preferentially during ice hockey. High physical activity seems to weaken the relationship between BMD and muscle strength. Hence, impact forces may be of greater importance in regulating bone mass than muscle strength in itself in highly trained athletes.

Absorptiometry, Photon↗

PubMed1999

Hemiosteoporosis after severe stroke, independent of changes in body composition and weight.

BACKGROUND AND PURPOSE: Fractures are a serious complication after stroke, and the risk of hip fractures among stroke patients is increased 2 to 4 times versus a reference population. Fractures after stroke are probably caused by the development of hemiosteoporosis and the high incidence of accidental falls. The aim of this study was to investigate the development of hemiosteoporosis in relation to other changes in body composition during the first year after severe stroke. METHODS: The study included 24 patients with extensive paresis after stroke. Bone mineral content (BMC) and fat and lean mass were assessed 1, 4, 7, and 12 months after stroke onset by a dual-energy x-ray absorptiometer. RESULTS: The loss of total body BMC was significant during the first year after stroke (-1.6%; P<0.05), but there were no significant changes in total lean or fat mass. At inclusion, there were no significant differences between sides in lean or fat mass or BMC, but during follow-up, BMC of the affected side decreased significantly compared with the same side at inclusion (-7.5%; P<0.01). Side differences in fat mass became significant between legs (9.3%; P<0.001) and whole sides (4. 8%; P<0.01). There were only minor side changes in lean mass. Loss of BMC was independent of weight changes. CONCLUSIONS: During the first year after severe stroke, patients developed pronounced hemiosteoporosis. This was not associated with general changes in lean or fat mass. The development of hemiosteoporosis was independent of weight changes after stroke.

Aged↗