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Biomedical subjects

M K Karlsson

Publications and source records attributed to M K Karlsson.

At least 19 recordsLinked to original sources
PubMed2006

Exercise, bone mass and bone size in prepubertal boys: one-year data from the pediatric osteoporosis prevention study.

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/cm(2)) 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-based and spare-time training correlated with L3 BMC (r=0.26, P=0.003), L3 aBMD (r=0.18, P=0.04) and L3 width (r=0.24, P=0.006). The study suggests that exercise in pre-pubertal boys influences the accrual of bone mineral and bone width and that a 1-year school-based exercise program confers skeletal benefits, at least in the lumbar spine.

Anthropometry↗
PubMed2006

Daily physical education in the school curriculum in prepubertal girls during 1 year is followed by an increase in bone mineral accrual and bone width--data from the prospective controlled Malmö pediatric osteoporosis prevention study.

The aim of this study was to evaluate a general school-based 1-year exercise intervention program in a population-based cohort of girls at Tanner stage I. Fifty-three girls aged 7-9 years were included. The school curriculum-based exercise intervention program included 40 minutes/school day. Fifty healthy age-matched girls assigned to the general school curriculum of 60 minutes physical activity/week served as controls. Bone mineral content (BMC, g) and areal bone mineral density (aBMD, g/cm(2)) were measured with dual X-ray absorptiometry (DXA) of the total body (TB), lumbar spine (L2-L4 vertebrae), third lumbar vertebra (L3), femoral neck (FN), and leg. Volumetric bone mineral density (g/cm(3)) and bone width were calculated at L3 and FN. Total lean body mass and total fat mass were estimated from the TB scan. No differences at baseline were found in age, anthropometrics, or bone parameters when the groups were compared. The annual gain in BMC was 4.7 percentage points higher in the lumbar spine and 9.5 percentage points higher in L3 in cases than in controls (both P < 0.001). The annual gain in aBMD was 2.8 percentage points higher in the lumbar spine and 3.1 percentage points higher in L3 in cases than in controls (both P < 0.001). The annual gain in bone width was 2.9 percentage points higher in L3 in cases than in controls (P < 0.001). A general school-based exercise program in girls aged 7-9 years enhances the accrual of BMC and aBMD and increases bone width.

Absorptiometry, Photon↗
PubMed2006

Daily physical activity related to body fat in children aged 8-11 years.

OBJECTIVE: To evaluate the association between objectively measured daily physical activity and body fat. STUDY DESIGN: Cross-sectional, observational, study of 248 children aged 7.9 to 11.1 years. Abdominal fat mass and total body fat mass were measured by dual-energy X-ray absorptiometry. Daily physical activity was assessed by accelerometers for 4 days. RESULTS: Total body fat expressed as a percentage of body mass was inversely related to minutes of vigorous physical activity per day, for all children r = -0.38 (P < .05). Children, both boys and girls, in the highest quartile of body fat performed on average 12 minutes less vigorous activity per day compared with their counterparts in the lowest quartile. Multiple regression analysis revealed that independent factors for body fat were number of minutes of vigorous activity per day and sex. CONCLUSION: Low physical activity can be a contributing factor in childhood obesity. Only longitudinal studies, however, can give more definitive information about the relation between daily physical activity and obesity.

Absorptiometry, Photon↗
PubMed2006

Reference values for respiratory system impedance by using impulse oscillometry in children aged 2-11 years.

The forced oscillation technique makes it possible to evaluate the mechanical properties of the respiratory system with a minimum of cooperation. The method is therefore especially useful in children. Impulse oscillometry (IOS) is a commercially available version of this technique. There is, as yet, limited information on reference values for IOS in children. The aim of this study was to extend the reference values for IOS variables and to study their correlation with height, weight and age in healthy children. A sample (n = 360) of children (age 2.1-11.1 years) was measured by using impulse oscillometry (IOS; Jaeger, Würzburg, Germany). The sample was based on children attending kindergarten in Finland and children attending primary school in Sweden. Measurements of respiratory resistance (Rrs) and reactance (Xrs) at 5, 10, 15 and 20 Hz, total respiratory impedance (Zrs) and the resonance frequency (Fr) were made. All variables were related to body height. Most of them were also weakly related to weight. Reference equations for children (height 90-160 cm) are presented.

Age Factors↗
PubMed2006

Daily physical activity in Swedish children aged 8-11 years.

INTRODUCTION: Physical inactivity is hypothesized to be a contributing factor in the development of a variety of diseases. Recommendations for an adequate level of physical activity have been proposed. There are few studies in which the physical activity in children has been objectively assessed. The purpose of this study was to estimate objectively the level of physical activity in Swedish children. MATERIALS AND METHODS: We studied 248 children (140 boys and 108 girls) aged 7.9-11.1 years from Malmö, Sweden. Physical activity was measured with accelerometers. Children were instructed to wear the accelerometers for 4 days. The mean daily activity was expressed as the mean counts per minute of recording. The time that the child spent performing moderate or vigorous activity was calculated by using previously established cutoff points. RESULTS: The mean daily activity was higher in boys than in girls, 751+/-243 vs 618+/-154 counts/min (P<0.001). All children fulfilled the recommendation for moderate physical activity for 60 min or more per day. Ninety-two percent of the boys and 86% of the girls performed vigorous activity, for 20 min or more per day. CONCLUSION: All children, aged 8-11 years, who participated in this study reached the recommended level of physical activity, with boys being more active than girls.

Child↗
PubMed2006

Displaced fractures of the neck of the radius in adults. An excellent long-term outcome.

We have reviewed 20 women and three men aged 22 to 73 years, who had sustained a Mason type-IIb fracture of the neck of the radius 14 to 25 years earlier. There were 19 patients with displacement of the fractures of 2 mm to 4 mm, of whom 13 had been subjected to early mobilisation and six had been treated in plaster for one to four weeks. Of four patients with displacement of 4 mm to 8 mm, three had undergone excision and one an open reduction of the head of radius. A total of 21 patients had no subjective complaints at follow-up, but two had slight impairment and occasional elbow pain. The mean range of movement and strength of the elbow were not impaired. The elbows had a higher prevalence of degenerative changes than the opposite side, but no greater reduction of joint space. Mason type-IIb fractures have an excellent long-term outcome if operation is undertaken when the displacement of the fracture exceeds 4 mm.

Adult↗
PubMed2005

Long-term morbidity and mortality after a clinically diagnosed vertebral fracture in the elderly--a 12- and 22-year follow-up of 257 patients.

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

Aged↗
PubMed2005

Physical activity in the post-pubertal period is associated with maintenance of pre-pubertal high bone density-- a 5-year follow-up.

OBJECTIVE: To evaluate the association between physical activity (PA) and skeletal growth in girls during adolescence. DESIGN: A 5-year, observational, population-based study (Reykjavik, Iceland). SUBJECTS: Seventy-eight Caucasian girls, mean age 13.4+/-1.0 (mean+/-SD) years at baseline. METHODS: Bone mineral density (BMD, g/cm2) and bone width (cm) were measured in the forearm by single-photon absorptiometry at baseline and with dual-energy X-ray absorptiometry after 3 and 5 years, when lumbar spine, femoral neck (FN) and total body were also evaluated. Half of the physically active girls were compared with the other half of less active girls. RESULTS: BMD in physically active girls was higher in the forearm at both baseline (P=0.001) and after 5 years (P=0.04) in comparison with less active girls. BMD was higher for the total body (P=0.0001), spine L2-L4 (P=0.02) and FN (P=0.002) in the active girls at age 18. The accrual of forearm BMD and bone width from age 13 to 18 was no different when comparing the two groups. CONCLUSIONS: Pre-pubertal PA is associated with high BMD at age 13 and continued PA is associated with maintenance of high BMD until age 18.

Absorptiometry, Photon↗
PubMed2004

Physical activity, skeletal health and fractures in a long term perspective.

Exercise during adolescence, especially during the pre-pubertal years, builds a skeleton with a high bone mineral density (BMD) and possibly a larger skeleton with a different skeletal architecture. This would lead to a stronger skeleton more resistant to trauma. These changes could be of biological significance for fracture reduction, if they were maintained into old age where fragility fractures exponentially rise. The Achilles heel of exercise is its cessation. Most BMD benefits achieved by exercise appear to be eroded with cessation of exercise. Reduced exercise intensity after a period of high activity, may maintain some residual BMD benefits into old age. A decreased fracture rate in the population could perhaps be achieved by promoting a physically active life style with lifelong high activity. But what happens if the activity in former athletes is reduced to the same level as in individuals who never exercised? The null hypothesis that exercise has no effect on fracture rates in old age cannot be rejected on the basis of any published, randomised, prospective data. Instead we have to rely on retrospective observational and case control studies, all hypothesis-generating, not hypothesis-testing. Existing data suggest that there could be a reduced fracture risk in former athletes. This notion may be correct, but consistently replicated sampling bias may produce the same observation and any biological explanation for this fracture reduction is unclear. Residual structural skeletal benefits, improved muscle strength, coordination and balance are all traits possibly maintained in former athletes after their active career. These traits may possibly reduce the number of fractures in later life.

Adolescent↗
PubMed2003

Pubertal bone growth in the femoral neck is predominantly characterized by increased bone size and not by increased bone density--a 4-year longitudinal study.

Fragility fractures are correlated to reduced bone size and/or reduced volumetric bone density (vBMD). These region-specific deficits may originate from reduced mineral accrual and/or reduced skeletal growth during the first 2 decades of life. Before pathological development can be defined, normal skeletal growth must be described. To evaluate growth of bone size, accrual of bone mineral content (BMC), areal bone mineral density (aBMD) and vBMD in a population-based cohort, 44 boys and 42 girls were followed by annual measurements from the age of 12 to 16 (attendance rates 90-100%). Segmental bone length, bone width, BMC, aBMD and vBMD were measured by dual-energy X-ray absorptiometry (DXA). Data were compared with predicted adult peak, as determined in 36 men aged 27.7+/-4.6 years and 44 women aged 26.8+/-4.9 years. Growth in width of the femoral neck precedes accrual of BMC in the femoral neck in both genders up to age 15. The girls were at all ages closer to their predicted adult peak in both bone width and BMC compared with the boys except in the femoral neck. As femoral neck vBMD had reached its predicted adult peak already at 12 years in both genders, the increase in femoral neck BMC and femoral neck aBMD from age 12 to 16 was most likely to be explained by the increase in bone size. In boys the peak velocity growth was recorded at ~14 years for BMC, height, width and lean mass. Growth from the age of 12 to 16 seems to build a bigger but not a denser skeleton in the femoral neck.

Adolescent↗
PubMed2003

Prevalent vertebral deformities predict increased mortality and increased fracture rate in both men and women: a 10-year population-based study of 598 individuals from the Swedish cohort in the European Vertebral Osteoporosis Study.

The aim of this study was to evaluate whether a prevalent vertebral deformity predicts mortality and fractures in both men and women. In the city of Malmö, 598 individuals (298 men, 300 women; age 50-80 years) were selected from the city's population and were included in the Swedish part of the European Vertebral Osteoporosis Study (EVOS). At baseline the participants answered a questionnaire and lateral spine radiographs were performed. The prevalence of subjects with vertebral deformity was assessed using a morphometric method. The mortality during a 10-year follow-up period was determined through the register of the National Swedish Board of Health and Welfare. Eighty-five men and 43 women died during the study period. The subsequent fracture incidence during the follow-up period was ascertained by postal questionnaires, telephone interviews and by a survey of the archives of the Department of Radiology in the city hospital. Thirty-seven men and 69 women sustained a fracture during the study period. Data are presented as hazard ratios (HR) with 95% confidence interval (95% CI) within brackets. Prevalent vertebral deformity, defined as a reduction by more than 3 standard deviations (SD) in vertebral height ratio, predicted mortality during the forthcoming decade in both men [age-adjusted HR 2.4 (95% CI 1.6-3.9)] and women [age-adjusted HR 2.3 (95% CI 1.3-4.3)]. In men there was an increased mortality due to cardiovascular and pulmonary diseases and in women due to cancer. Prevalent vertebral deformity predicted an increased risk of any fracture during the forthcoming decade in both men [age-adjusted HR 2.7 (95% CI 1.4-5.3)] and women [age-adjusted HR 1.8 (95% CI 1.1-2.9)]. Prevalent vertebral deformity predicted an increased risk of any subsequent fragility fracture in women [age-adjusted HR 2.0 (95% CI 1.1-3.5)]; however, in men the increased risk was nonsignificant [age-adjusted HR 1.9 (95% CI 0.7-5.1)]. In summary, a prevalent vertebral deformity can predict both increased mortality and increased fracture incidence during the following decade in both men and women. We conclude that prevalent vertebral deformity could be used as a risk factor in both genders for mortality and future fracture.

Aged↗
PubMed2003

Hip fracture patients have more vertebral deformities than subjects in population-based studies.

The prevalence of vertebral deformity, estimated in lateral spine radiographs (Th4-L4) using quantitative morphometry, in 64 men and 132 women with hip fractures was compared with the prevalence of vertebral deformity in individuals in two population-based studies. A vertebral deformity of a specific vertebra was defined as a 3, 4, or 5 SD reduction from the normal mean of any of three ratios describing that specific vertebra. The age-adjusted prevalence of individuals with vertebral deformities was higher among the hip fracture patients than among the reference subjects in both genders, with an odds ratio of 3.6 [95% confidence interval (CI) 1.9-6.6] in men and 2.6 (95% CI 1.7-4.1) in women using deformity criterion -3 SD. Also, the number of vertebrae with deformities (-3 SD) in individuals with one deformity or more was greater among the hip fracture patients than among the reference subjects (in men mean 2.3 versus 1.8, P = 0.007; in women mean 3.3 versus 2.0, P < 0.001). Adjusted for age there were more vertebrae with deformities (-3 SD) among female than among male hip fracture patients (mean 3.3 versus 2.3, P = 0.01). We found no differences in the vertebral deformity rates when comparing patients with a per- or subtrochanteric hip fracture with patients with a cervical hip fracture. In conclusion, there is a relationship between vertebral deformities and hip fractures suggesting that a prevalent vertebral deformity could predict an increased hip fracture risk.

Aged↗
PubMed2002

Physical activity increases bone size in prepubertal boys and bone mass in prepubertal girls: a combined cross-sectional and 3-year longitudinal study.

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 < 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 < 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.

Absorptiometry, Photon↗
PubMed2001

Exercise may induce reversible low bone mass in unloaded and high bone mass in weight-loaded skeletal regions.

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 < 0.001), 1.4 +/- 6.3% higher BMD in the arm (NS) and 12.7 +/- 9.8% higher BMD in the femoral neck (p<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.

Absorptiometry, Photon↗
PubMed2001

Peripubertal moderate exercise increases bone mass in boys but not in girls: a population-based intervention study.

On the basis of cross-sectional studies in elite athletes and longitudinal studies, physical activity in growing children has been suggested to enhance bone mineral acquisition and prevent osteoporosis later in life. The level of exercise in most of these studies is not applicable in a population on a day-to-day basis. The aim of this study was to determine whether moderate increased exercise within the school curriculum from age 12 to 16 years would have anabolic bone effects. In a population-based setting of 40 boys and 40 girls the school curriculum was enhanced to physical education 4 times per week for 3-4 years. Controls were 82 boys and 66 girls who had had physical education twice a week over a corresponding period. Both cases and controls were measured at age 16 years. Bone mineral content (BMC), areal bone mineral density (aBMD), bone size (femoral neck width) and volumetric BMD (vBMD) were measured in total body, spine and femoral neck (FN) by dual-energy X-ray absorptiometry. Data are presented as mean +/- SD. BMC (8 +/- 15%, p = 0.04), aBMD (9 +/- 13%, p = 0.002) and vBMD (9 +/- 15%, p = 0.001) were all higher in FN in the male intervention group compared with controls. FN bone size was no higher in the intervention group than in the controls. In girls, no differences were found when comparing the intervention group with controls. The results remained after adjusting for confounding factors such as weight, height, milk intake and activity after school. In summary, we report that increased bone mass can be achieved in a population-based cohort of boys (but not in girls) by moderate increased physical activity within the school curriculum from age 12 to 16 years. We speculate that the same results can be seen in girls if intervention starts at an earlier age. We conclude that increasing the physical education content of the Swedish school curriculum may improve bone mass in at least peripubertal boys.

Absorptiometry, Photon↗
PubMed2001

Skeletal effects of exercise in men.

No prospective randomized study with fracture as end point exists in men. Data from retrospective and prospective observational and case control studies suggest that activity in men is associated with reduced fracture risk. This may be correct, but consistently replicated sampling bias may produce the same observation, as these studies are hypothesis generating, never hypothesis testing. Higher musculoskeletal mass, better health, coordination, and less tendency to fall may lead to exercise, not the reverse. It would be extremely difficult to conduct an exercise intervention study with fracture as the end point because of the large cohorts needed. However, showing a positive effect on surrogate end points for fractures as increased bone mass or reduced fall frequency would support the notion that exercise has a fracture-protective effect. Exercise during growth seems to build a larger and stronger skeleton in boys. However, cessation of exercise is its Achilles heel; biologically important increased peak bone mass or improvement in muscle strength achieved by exercise during growth may be eroded in retirement, leaving no biological significant benefits in old age when fractures occur. Exercise during adulthood may prevent bone loss or produce a small increase in BMD of a few percent, probably a non-biologically significant increase in reducing the fracture risk in elderly men. However, exercise in adults seems to increase muscle strength and improve balance, with reduced fall frequency as the result and maybe reduced frequency of injuries also. The effects of exercise on bone size, shape, and architecture during growth and adolescence must be defined as well as the effect of muscle function, fall frequency, and frequency of injurious falls in elderly men. Also, continued low level of exercise may maintain some of the benefit after more vigorous activity level during younger years, but dose-response relationships need to quantified. Additionally, the null hypothesis that exercise has no effect on fracture rates in old age cannot be rejected by any published data. The proof rests on demonstration of a reduction in spine and hip fractures in well-designed and executed prospective, open-randomized studies, none of which exist. Our inability to answer these questions should be acknowledged before recommendations are made at the community level.

Accidental Falls↗