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Biomedical subjects

O L Svendsen

Publications and source records attributed to O L Svendsen.

35 records · Page 2Linked to original sources
PubMed1995

Impact of soft tissue on in vivo accuracy of bone mineral measurements in the spine, hip, and forearm: a human cadaver study.

The impact of soft tissue in vivo on accuracy of bone mineral density (BMD) measurements of the spine and hip by dual energy X-ray absorptiometry and of the forearm by single photon absorptiometry was assessed by use of 14 human cadavers. The in vivo accuracy errors (SEE%) were: forearm 3-5%, anteroposterior spine 5.3%, lateral spine 10-12%, and femoral greater trochanter, neck, total, intertrochanteric, and Ward's triangle 3%, 6.5%, 6.7%, 8%, and 11-13%, respectively. Except from the lateral spine and the greater trochanter, the slopes of the linear regressions of in vivo BMD against in vitro BMD were not significantly different from 1 (p > 0.05). The calculated random accuracy error of BMD measurements due to fat inhomogeneity was estimated to 3-4% for the anteroposterior spine and 9-14% for the lateral spine (from abdominal computed tomography in 26 healthy women). In conclusion, acceptable accuracy errors below 6-7% (of soft tissue in vivo) of BMD measurements were obtained in the anteroposterior spine, the forearm, and the neck, greater trochanter, and total proximal femur.

Absorptiometry, Photon↗
PubMed1995

Age- and menopause-associated variations in body composition and fat distribution in healthy women as measured by dual-energy X-ray absorptiometry.

To assess the variation with age and menopause, 407 healthy normal women aged 18 to 75 years had body composition and fat distribution measured by dual-energy x-ray absorptiometry (DEXA). The mean +/- SD are given for different age decades. Postmenopausal women had significantly more fat, a more central fat distribution, and less lean tissue mass (LTM) than premenopausal women. In premenopausal and postmenopausal women, age only correlated with the abdominal to total-body fat tissue ratio (r approximately .24, P < .05), whereas the years since onset of menopause correlated with fat tissue mass (FTM), fat%, abdominal fat%, and the abdominal to total-body fat tissue ratio (r approximately .2, P < .05). To assess the independent impact of age, menopausal status, and years since menopause, multiple linear regressions were performed. FTM, fat%, and abdominal fat% were significantly related to menopausal status and years since menopause independently of age. The abdominal to total-body fat tissue ratio was statistically significantly related to age, but tended also to be independently related to years since menopause. LTM was statistically significantly related to menopausal status independently of age and years since menopause. In summary, we suggest that in healthy women total-body and abdominal fat may increase and LTM may decrease in the years after menopause, primarily in the perimenopausal years, without significant changes before menopause.

Absorptiometry, Photon↗
PubMed1995

The response to treatment of overweight in postmenopausal women is not related to fat distribution.

OBJECTIVE: To investigate whether fat distribution or sex hormone status in overweight postmenopausal women do influence the response to treatment of overweight. DESIGN: Longitudinal, clinical intervention study of a 4.2 MJ diet daily with or without exercise. SUBJECTS: 98 healthy, overweight, postmenopausal women (age: 49-58 y, BMI: 25-42 kg/m2). MEASUREMENTS: Various fatness and fat distribution parameters (by dual-energy x-ray absorptiometry and anthropometry), sex hormone-binding globulin (SHBG), sex hormones, and the resting energy expenditure (REE) at baseline and after 3 months. RESULTS: Reductions in weight and fat were independent of the initial fat distribution and the REE, but were significantly associated with high initial SHBG levels. Furthermore, loss of fat was significantly and independently associated with increases in SHBG and reductions in central fat distribution. CONCLUSION: Postmenopausal women with an android and gynoid fat distribution respond with similar weight loss to treatment of overweight. Furthermore, a more healthy, less android, fat distribution and sex hormone status may be achieved with increasing weight loss.

Absorptiometry, Photon↗
PubMed1994

[Physical exercise as a supplement to diet. Effect on body composition, resting metabolic rate and cardiovascular risk factors in postmenopausal overweight women].

One hundred and twenty-one healthy, overweight, postmenopausal women were randomly assigned to three groups: controls (no intervention), a 4200 kJ/day diet, or 4200 kJ/day diet with combined aerobic and anaerobic exercise, for 12 weeks. One hundred and eighteen women completed the study. The loss of weight was similar in the two intervention groups, but compared with the diet-only group, the diet-plus-exercise group lost significantly more fat (7.8 vs 9.6 kg) and no lean tissue mass (1.2 vs 0.0 kg). The resting metabolic rate was increased in the diet-plus-exercise group as compared to the controls (11% vs 4%, p < 0.009). The cardiovascular risk factors (serum lipids and lipoproteins (except high density lipoprotein), systolic blood pressure, and the waist-to-hip ratio) decreased significantly in both intervention groups, as compared to the controls. There were no consistent, major differences between groups in changes in total body, spinal, or forearm bone mineral density. In conclusion, overweight postmenopausal women benefit from addition of combined aerobic and anaerobic exercise to an energy-restrictive diet.

Aged↗
PubMed1994

Six months' follow-up on exercise added to a short-term diet in overweight postmenopausal women--effects on body composition, resting metabolic rate, cardiovascular risk factors and bone.

The aim of this work was to study the long-term effects of the addition of exercise to a short-term diet in overweight postmenopausal women. A follow up study was made of 118 overweight, postmenopausal women, who 6 months earlier had completed 12 weeks of randomized intervention (three groups: 4.2 MJ/d diet, 4.2 MJ/d diet with exercise, and controls). The following were measured: body composition and fat distribution (measured by dual-energy X-ray absorptiometry), resting metabolic rate, serum lipids and lipoproteins, blood pressure, and bone mineral densities. It was found that weight was still significantly reduced (by about 8 kg). HDL-C was significantly increased (10%), and triglycerides decreased (20%), whereas the initial reductions in total cholesterol and LDL-C had disappeared at the follow-up. The women from the former diet-plus-exercise group, who were current exercisers at the follow-up, had a significantly greater reduction in weight (10.9 vs 6.6 kg), fat tissue mass (10.0 vs 5.4 kg) and abdominal-to-total-body fat tissue mass (9.6 vs 4.7), and a significantly greater increase in the resting metabolic rate (11.1 vs 1.1 kJ/kg/d), as compared with the non-exercisers from this group. There were no major detrimental changes in total body, spinal, or forearm bone mineral density or in markers of bone turnover. The short-term dietary treatment in this study may have beneficial long-term effects on weight, fat tissue mass and cardiovascular risk factors with no additional benefits from added exercise, unless the exercise is continued.

Body Composition↗
PubMed1993

Effect of an energy-restrictive diet, with or without exercise, on lean tissue mass, resting metabolic rate, cardiovascular risk factors, and bone in overweight postmenopausal women.

PURPOSE: To study the effect of exercise added to an energy-restrictive diet in overweight postmenopausal women. SUBJECTS AND METHODS: In a longitudinal clinical study, 121 healthy, overweight postmenopausal women (age 53.8 +/- 2.5 years, body mass index: 29.7 +/- 3.1 kg/m2) were randomly assigned to 3 groups: controls, a 4,200 kJ/d diet, or a 4,200 kJ/d diet with combined aerobic and anaerobic exercise. Body composition (measured by dual-energy x-ray absorptiometry), fat distribution, resting metabolic rate, blood pressure, serum lipids and lipoproteins, bone mineral densities, and markers of collagen and bone turnover were measured before and after 12 weeks of intervention. RESULTS: One hundred eighteen women completed the study. The mean loss of body weight (9.5 kg versus 10.3 kg, NS) was similar in the intervention groups, but compared with the diet-only group, the diet-plus-exercise group lost more fat (7.8 kg versus 9.6 kg, p < 0.001) and no lean tissue mass (1.2 kg versus -0.0 kg, p < 0.001). The resting metabolic rate (per kg wt) was increased in the diet-plus-exercise group compared with the control group (11% versus 4%, p < 0.009). The levels of serum triglycerides, total cholesterol, low-density lipoprotein, and very-low-density lipoprotein decreased, and the ratio of high-density lipoprotein to low-density lipoprotein increased by 20% to 30% in both intervention groups compared with the control group (p < 0.001). The systolic blood pressure dropped, and the waist-to-hip circumference ratio and abdominal-to-total body fat decreased in both intervention groups compared with the control group (10%, p < 0.003, and 3.5%, p < 0.0001). There were no consistent, major differences between the groups in terms of changes in total body, spinal, or forearm bone mineral densities, or in markers of collagen and bone turnover. CONCLUSION: Overweight postmenopausal women benefit from addition of combined aerobic and anaerobic exercise to an energy-restrictive diet. The diet itself has a positive effect on cardiovascular risk factors.

Blood Pressure↗
PubMed1993

Impact of regional and total body composition and hormones on resting energy expenditure in overweight postmenopausal women.

The independent impact of regional and total body composition and sex and thyroid hormone levels on resting energy expenditure (REE) was assessed in 121 healthy, overweight (body mass index [BMI], 25 to 42 kg/m2), postmenopausal women (aged 49 to 58 years). REE was measured by indirect calorimetry with a ventilated hood, and the total, trunk, and peripheral body composition by dual-energy x-ray absorptiometry (DXA). Sex and thyroid hormone levels were also measured. REE correlated significantly (P < .05) better with trunk lean tissue mass ([LTM] r = .61) than with total-body (r = .53) or peripheral LTM (r = .30). Trunk LTM (R2 = .37), total-body fat tissue mass ([FTM] R2 = .04), androstenedione (R2 = .03), and total triiodothyronine ([T3] R2 = .02) were all significantly independently associated with REE. Together they explained 46% (model R2) of the interindividual variation in REE, with a standard error of estimate (SEE) of 549 kJ/d. We conclude that the interindividual variation in REE is explained mainly by differences in the visceral component of LTM, with additional minor information from the total-body FTM, androstenedione, and T3.

Absorptiometry, Photon↗
PubMed1993

Accuracy of measurements of body composition by dual-energy x-ray absorptiometry in vivo.

The accuracy of body-composition measurements in vivo by dual-energy x-ray absorptiometry (DEXA) was assessed in seven pigs (weight: 35-95 kg) by measurement by DEXA in vivo and chemical analysis after postmortem homogenization. The regression lines between these measurements were not significantly different from the line of identity (P > 0.05), the r values were > 0.97, and the corresponding SEEs were 2.9%, 1.9 kg, and 2.7 kg for percent fat, fat tissue mass, and lean body mass, respectively. Changes in fat and lean tissue mass (simulated by placing 8.8 kg porcine lard on the trunk of six women) were accurately measured by DEXA. The measured total-body bone mineral (TBBM) was significantly affected by the lard (P < 0.05). In conclusion, DEXA is an accurate method for measurement of soft-tissue body composition. TBBM measurements in longitudinal studies may, however, be difficult to interpret if considerable change in soft-tissue composition has occurred.

Absorptiometry, Photon↗
PubMed1993

Measurement of abdominal and intra-abdominal fat in postmenopausal women by dual energy X-ray absorptiometry and anthropometry: comparison with computerized tomography.

The aim was to develop a model for prediction of intraabdominal adipose tissue (AT) with combined dual energy X-ray absorptiometry (DXA) and anthropometry in postmenopausal women. Intra-abdominal and subcutaneous AT from the 1st to the 4th lumbar intervertebral disk was measured by computerized tomography (CT) (as a reference method) in 25 postmenopausal women (BMI 19.9-35.1 kg/m2). Fat was measured in the corresponding region by DXA. Abdominal sagittal diameters, skinfold thicknesses, and circumferences were also measured. Measurements of abdominal fat by CT and DXA were valid (r = 0.9, s.e.e.%: 7%). Measurement of abdominal fat by DXA explained about 80% of the variation in the intra-abdominal AT (by CT), whereas the waist to hip ratio was the only variable that correlated significantly with the intra-abdominal to subcutaneous AT ratio. Abdominal fat measured by DXA, the waist to hip ratio, and the sum of trunk skinfold thicknesses could in combination accurately predict the intra-abdominal AT measured by CT (r2 = 0.91, s.e.e.% = 15%). The sagittal diameter, measured either anthropometrically or by CT, was not a superior predictor of the intra-abdominal AT. We conclude that the intra-abdominal AT can be predicted in postmenopausal women by DXA combined with anthropometry.

Abdomen↗
PubMed1993

Relationships and independence of body composition, sex hormones, fat distribution and other cardiovascular risk factors in overweight postmenopausal women.

The relationships and independence of body composition, sex hormones, fat distribution and other cardiovascular risk factors were studied in 121 overweight postmenopausal women. Body composition and fat distribution were directly measured by dual energy X-ray absorptiometry (DXA); other parameters were waist-to-hip ratio (WTH), sex hormone binding globulin (SHBG), testosterone, androstenedione (A), oestradiol (E2), and lipids and lipoproteins; cigarette and alcohol consumption were recorded. SHBG was correlated with the fat distribution by DXA and WTH (r = -0.35, P < 0.01) and A with the fat mass (r = -0.3, P < 0.01). SHBG had a negative and alcohol and cigarette consumption a positive, independent relationship to a central fat distribution (by DXA and WTH, respectively) (P < 0.01). SHBG (r = 0.23, P < 0.05), fat distribution (WTH) and A (r = -0.2 to -0.3, P < 0.01) were correlated with high density lipoprotein cholesterol (HDL-C). However, only fat distribution (WTH) and A were independently related to HDL-C (P < 0.05). Fat distribution (WTH) and SHBG were independently related to triglycerides (P < 0.05), whereas fat distribution (by DXA) and E2 were independently associated with total cholesterol and low density lipoprotein cholesterol (LDL-C) (P < 0.05). Thus, in overweight postmenopausal women, androgenicity and cigarette and alcohol consumption were independently positively related to a central fat distribution. Furthermore, atherogenic levels of lipids and lipoproteins were independently related to a central fat distribution, androgenicity and low levels of oestrogens.

Absorptiometry, Photon↗
PubMed1992

Measurements of bone mineral density of the proximal femur by two commercially available dual energy X-ray absorptiometric systems.

Two dual energy X-ray absorptiometric (DXA) instruments have recently become commercially available for local bone densitometry: the QDR-1000 (Hologic Inc.) and the DPX (Lunar Radiation Corp.). We report the precision, influence of femoral rotation, correlation and agreement of bone mineral measurements of the proximal femur by these two instruments. In vitro (femur phantom) short-term precision was 1.1%-3.5%, and the long-term precision was 1.2%-3.8%. In vivo (groups of 10 premenopausal and 10 post-menopausal women) short-term precision of duplicate measurements was 1.6%-4.7%, and long-term precision was 1.9%-5.5%. Overall, the precision for Ward's triangle was over 3% and that for the femoral neck and trochanter, 2%-3%. Rotation of a femur phantom produced a statistically significant change in the bone mineral density (BMD) of the femoral neck. Within a clinically relevant range of femoral rotation (20 degrees inward rotation +/- 5 degrees) the coefficient of variation (CV%) increased by a mean factor of 1.1-1.4. Although the correlation (r less than 0.9) between BMD measurements of the proximal femur by the DPX and QDR-1000 in 30 postmenopausal women was high, there was lack of agreement between the two instruments. We found no statistically significant differences between the right and left femur in 30 postmenopausal women. A bilateral femur scan took a mean total time of about 22 min. We conclude that with the introduction of DXA instruments, the precision of bone mineral measurements of the proximal femur has improved. However, for comparability between commercially available DXA instruments, it might be advantageous if units were standardized.

Absorptiometry, Photon↗
PubMed1992

Progestogens do not affect aortic accumulation of cholesterol in ovariectomized cholesterol-fed rabbits.

Cardiovascular disease is a major killer in postmenopausal women in the industrialized societies. To investigate the effect of progestogen and 17 beta-estradiol replacement therapy on atherogenesis, we studied 60 cholesterol-fed ovariectomized rabbits for 13 weeks. They were randomly assigned to four groups of 15 rabbits each and received oral treatment with norethisterone acetate, levonorgestrel, 17 beta-estradiol, or placebo. The active treatment groups achieved serum hormone concentrations, which produced physiological effects on the uterus. No significant differences in serum total cholesterol or ultracentrifuged lipoproteins (very low density, intermediate density, low density, or high density lipoproteins) were found between the four groups during the experimental period. There were no significant differences between the progestogen and placebo groups in the aortic accumulation of cholesterol. The estradiol group had only accumulated about half the aortic cholesterol as compared with the placebo group and the progestogen groups (p less than 0.05). The antiatherogenic effect of 17 beta-estradiol was estimated to be equal to a 40-50% reduction in serum total cholesterol. These findings suggest that two commonly prescribed 19-nortestosterone-derived progestogens, which are considered to be "atherogenic," do not affect atherogenesis in cholesterol-fed ovariectomized rabbits, whereas 17 beta-estradiol produces a significant antiatherogenic effect that is independent of lipid metabolism in plasma, possibly the result of a direct action on the arterial wall.

Analysis of Variance↗
PubMed1992

Changes in calcanean bone mineral occurring spontaneously and during hormone replacement therapy in early post-menopausal women.

The spontaneous calcanean bone loss occurring in healthy early post-menopausal women and the effect of two hormone replacement therapies (HRT's) were investigated in a longitudinal study. There was no difference between the right and left calcanean BMC or BMD (p > 0.15). The spontaneous bone loss was similar at all the skeletal sites measured, with a mean spontaneous loss in calcanean BMD of 1.6% over one year. Both HRT's significantly (p < 0.01) prevented the bone loss from all skeletal sites irrespective of the weight-bearing or content of trabecular bone, and (for the weight-bearing bones) there was even a gain in calcanean BMC and BMD and spinal BMD (p < 0.01). Bone mineral of the calcaneus and the spine correlated equally to body weight (r approximately 0.4, p < 0.001), whereas bone mineral in the forearm was not correlated to body weight. The correlations between the changes in bone mineral at the sites measured were all significant (r approximately 0.2-0.4).

Bone Density↗
PubMed1991

Measurement of body fat in elderly subjects by dual-energy x-ray absorptiometry, bioelectrical impedance, and anthropometry.

Body fat was measured in 46 elderly subjects by dual-energy x-ray absorptiometry [BF(DEXA)], bioelectrical impedance analysis (BIA), and anthropometry. Equations for prediction of the body fat (by DEXA) of elderly people by BIA and/or anthropometry were developed. The prediction of body fat (by DEXA) by anthropometric variables alone gave an r2 of 0.94 and the corresponding SEEs were 1.61 kg for men and 2.43 kg for women. When BIA variables were added as predictors, r2 increased by 2-5% (P less than 0.05) and the corresponding SEE decreased by 25% (P less than 0.05). The prediction of body fat (by DEXA) in elderly subjects and by BIA or anthropometry with equations developed in populations of young healthy adults (adapted from the literature) was generally not good although the correlation coefficients were high (r greater than 0.9, P less than 0.001), which suggests that our equations may improve prediction of body fat in elderly subjects.

Absorptiometry, Photon↗