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PubMed1998

Type of physical activity, muscle strength, and pubertal stage as determinants of bone mineral density and bone area in adolescent boys.

The present study was conducted to evaluate the influence of different types of weight-bearing physical activity, muscle strength, and puberty on bone mineral density (BMD, g/cm2) and bone area in adolescent boys. Three different groups were investigated. The first group consisted of 12 adolescent badminton players (age 17.0 +/- 0.8 years) training for 5.2 +/- 1.9 h/week. The second group consisted of 28 ice hockey players (age 16.9 +/- 0.3 years) training for 8.5 +/- 2.2 h/week. The third group consisted of 24 controls (age 16.8 +/- 0.3 years) training for 1.4 +/- 1.4h/week. The groups were matched for age, height, and pubertal stage. BMD, bone mineral content (BMC, g), and the bone area of the total body, lumbar spine, hip, femur and tibia diaphyses, distal femur, proximal tibia, and humerus were measured using dual-energy X-absorptiometry. When adjusting for the difference in body weight between the groups, the badminton players were found to have significantly higher BMD (p < 0.05) of the trochanter and distal femur compared with the ice hockey players despite a significantly lower weekly average training. The badminton players had higher BMD compared with the control with the control group at all weight-bearing BMD sites, except at the diaphyses of the femur and tibia and lumbar spine. The independent predictors of bone density were estimated by adjusting BMC for the bone area in a multivariate analysis among all subjects (n = 64). Accordingly, the bone density of all sites except the spine was significantly related to muscle strength and height, and the bone density of the total body, neck, trochanter, distal femur, and proximal tibia was significantly related to type of physical activity (beta = 0.09-0.33, p < 0.05). The bone area values at different sites were strongly related to muscle strength and height and less strongly related to the type of physical activity and pubertal stage. In conclusion, it seems that during late puberty in adolescent boys the type of weight-bearing physical activity is an important determinant of bone density, while the bone area is largely determined by parameters related to body size. The higher BMD at weight-bearing sites in badminton players compared with ice hockey players, despite significantly less average weekly training, indicates that physical activity including jumps in unusual directions has a great osteogenic potential.

Absorptiometry, Photon↗

PubMed2003

Precision of bone densitometry measurements: when is change true change and does it vary across bone density values?

The precision error of the bone densitometer is used to interpret significant change in bone mineral density (BMD) in serial studies. The precision error can be expressed as standard deviation (SD) or coefficient of variation (CV). The aims of this study are to determine the precision error over a range of BMD values and to demonstrate the application of the precision error in clinical practice. A bone phantom was used consisting of a perspex block with eight compartments containing varying amounts of hydroxyapatite powder to simulate a range of bone densities. The block was scanned 21 times and manual regions placed over each compartment to measure the BMD in each compartment. There were no significant differences in the variances or SD for all eight compartments, that is, over the range of BMD normally encountered in clinical practice. However, the calculated CV show a progressive fall in values as the BMD rises. Therefore, the SD should be used to calculate significant BMD change. In a practise with quality control procedures in place to detect calibration drift and with appropriately trained personnel, a change of approximately 0.05 g/cm2 is generally regarded as being a significant change at a 95% confidence level.

Absorptiometry, Photon↗

PubMed1994

Bone density of normal women in relation to endogenous and exogenous oestrogens.

To evaluate the relationship between duration of hormone replacement therapy (HRT) and forearm bone density, a population-based study has been conducted of 4638 women comparing bone density of 1079 women who had taken HRT for varying times with those who had never taken it. Forearm bone mineral content (BMC) was measured by single photon absorptiometry. Additionally, free oestradiol and sex hormone binding globulin levels were measured in women with high and low bone mineral content. There were no detectable differences in BMC in those who took HRT for up to 24 months compared with those who did not. Thereafter there were significant positive regression coefficients for duration periods of 2 to 5 yr (beta = 0.77, P = 0.04 and beta = 1.76, P = 0.03) and more than 5 yr (beta = 1.66, P < 0.0005 and beta = 1.87, P = 0.009) in post-menopausal and oophorectomized women. The major determinants of BMC were height, and in post-menopausal or oophorectomized women, age. Weight and parity also had additional explanatory power for pre- and post-menopausal women. Those who were in the highest quintile of BMC but had never taken HRT showed significantly elevated percentage free oestradiol compared with those in the lowest quintile. Thus HRT is osteoprotective if taken after the menopause for more than 24 months.

Adult↗

PubMedDate not supplied

Prevention of loss of vertebral bone density in heart transplant patients.

Seventy-six patients (63 men, 13 women) have been followed up by vertebral bone density (VBD) studies from 3 to 36 months. VBD was measured by single-energy computerized tomographic scan. Before transplantation, VBD was found to be lower than in age-matched controls (less than 40 years of age [group 1], 96% of controls: 40 through 49 years of age [group 2], 77%; 50 to 60 years of age [group 3], 87%; more than 60 years of age [group 4], 76%). After transplantation, despite oral calcium supplements, VBD fell further in all but two patients (97%), which was almost certainly related to maintenance steroid and cyclosporine therapy, and was most marked in the older groups (group 2, 67% compared with age-matched controls at 6 months; group 3, 60%; group 4, 50%). Intensive therapy with synthetic salmon calcitonin (in 29 of 76 patients [38%]), testosterone (in 33 of 63 men [52%]), or estrogen (in 12 of 13 women [92%]) limited, but did not totally prevent, further loss in VBD; in patients who had shown an approximate 45% loss of VBD from pretransplantation levels, further loss was reduced to between 4% and 10%. Five patients increased bone density after calcitonin therapy. Despite significantly reduced VBD in several older patients, minor vertebral bone compression developed in only one patient. We recommend that all patients undergoing heart transplantation, particularly those over the age of 50 years, should be followed by VBD studies, and therapy should be administered to prevent VBD loss.

Adult↗

PubMed2004

Lack of independent relationship between plasma adiponectin, leptin levels and bone density in nondiabetic female adolescents.

OBJECTIVES: Adiponectin has been implicated in the pathophysiology of metabolic syndrome and coronary artery disease in humans. Whether adiponectin is related to bone mineralization remains unclear in adults as well as in adolescents. In this study, we aimed to determine the relationship between plasma adiponectin, leptin concentrations and bone density, including total-body bone mineral density (BMD) and bone mineral content (BMC) in adolescence. PATIENTS AND MEASUREMENTS: We studied 105 nondiabetic female adolescents [mean age 15.4 +/- 1.9 years, and mean body mass index (BMI), 23.1 +/- 4.0 kg/m(2)]. A venous blood sample was taken after 12 h of fasting to measure fasting plasma adiponectin and leptin levels. BMD and BMC of the whole body were measured by dual-energy X-ray absorptiometry. RESULTS: In simple correlation analysis, plasma adiponectin and leptin levels correlated significantly with total-body BMD (r =-0.523 and r = 0.443, P < 0.001, respectively) and BMC (r =-0.471 and r = 0.396, P < 0.001, respectively). However, plasma adiponectin and leptin were related to both BMD and BMC in opposite directions. In multivariate linear regression analyses, only BMI or fat mass (FM) and Tanner stage, but not plasma adiponectin and leptin, were significantly related to BMD and BMC following adjustment for other variables. CONCLUSIONS: The results suggest that plasma adiponectin and leptin concentrations are not related to the total-body BMD and BMC independent of the chronological age, BMI or FM, and Tanner stage in nondiabetic female adolescents, although they were highly correlated in simple correlation analyses. The biologic roles of adiponectin in bone still need further clarification.

Adiponectin↗

PubMed2003

Menopause and bone density issues for women with epilepsy.

Menopausal women with epilepsy present several unique management challenges. They have an elevated risk for osteoporotic fracture because of the adverse effects of antiepileptic drugs (AEDs) on bone metabolism, combined with the chance of trauma during seizures and the subtle effects of AEDs on coordination that promote falling. A uniform effect of AEDs on vitamin D metabolism or bone turnover has not yet been revealed by clinical or basic studies, although the enzyme-inducing AEDs appear to decrease serum vitamin D levels. However, bone density is frequently decreased in patients with epilepsy. Clinicians must be familiar with the recommendations for calcium and vitamin D supplementation and recognize when to refer patients for bone density evaluations. Perimenopause is a transition during which women with epilepsy are at risk for increased seizure frequency, probably because of alterations in the estrogen:progesterone ratio over this period. Women with epilepsy who have had a catamenial seizure pattern during their reproductive years are at particular risk for an increase in seizure frequency during perimenopause but may experience a seizure reduction after becoming menopausal (cessation of menses for 1 year). These women appear to represent a subgroup of patients with epilepsy who have heightened sensitivity to endogenous reproductive hormone levels. The use of hormone replacement therapy may also increase seizure occurrence. Finally, the age at menopause may be reduced in women with poorly controlled seizures. This is probably related to an effect of seizures on hypothalamic function, although primary ovarian dysfunction may also be operative in this setting.

Adult↗

PubMed1998

Gonadal status is an important determinant of bone density in acromegaly.

OBJECTIVE: To measure bone mineral density (BMD) in patients with acromegaly and to look for clinical features which may explain previously reported discrepant results. DESIGN: Prospective case controlled observational study. PATIENTS: 18 patients with acromegaly (seven women, 11 men; mean age 53.2 +/- 3.5 years). Eight patients had active disease and 10 had controlled acromegaly. Growth hormone and insulin-like growth factor-1 (IGF-1) concentrations were measured to assess disease activity. MEASUREMENTS: BMD was measured at four sites on the lumbar spine, three at the femoral neck and at Ward's triangle using a Hologic dexa scanner. Results were compared to a locally determined control population (n = 1800). In eight patients with active acromegaly, urinary free pyridinoline and deoxypyridinoline, and serum osteocalcin, propeptide of type 1 procollagen, vitamin D, 1000 h parathyroid hormone, bone specific alkaline phosphatase, calcium and phosphate concentrations were measured before and after 6 months treatment with octreotide. RESULTS: The mean BMD for all acromegalic patients was not significantly different from the control population except at the femoral neck where it was increased (P = 0.05). At all sites, the BMD of patients who had been hypogonadal (n = 12/18) was significantly lower (P < 0.05-0.01) than that of patients who had been eugonadal (n = 6/18). BMD for hypogonadal patients was lower than the control population at Ward's triangle (P = 0.03). Eugonadal acromegalic patients had BMD greater than non-acromegalic controls at all sites. Patients with controlled acromegaly had a higher BMD than non-acromegalic controls, but there were no differences in BMD between patients with active and controlled acromegaly. Serum IGF-1 concentrations decreased from 64.5 +/- 5.1 nmol/l to 37.5 +/- 6.9 nmol/l (P = 0.02) after 6 months treatment with octreotide, but there was no change in any of the biochemical markers of bone turnover. CONCLUSIONS: Eugonadal acromegalic patients have increased lumbar spine and femoral neck BMD compared to hypogonodal acromegalic patients and the general population, but it is reduced if patients have been hypogonadal.

Acromegaly↗

PubMed1993

[Bone density and mineral content in normal men. Measurement by dual photon densitometry].

The aim of this study was to measure whole body, L2 to L4 vertebral bodies and femoral neck bone density and mineral content, using a dual photon densitometer with a 153Gd source, in normal male subjects. One hundred twenty five males, aged 20 to 85 years, were studied. Subjects were separated, according to age in 5 year groups, with at least 10 subjects per group. Height did not show secular changes until 70 years of age, but a 9 kg increase in weight and a 3.8 kg/m2 increase in body mass index was observed. Lumbar spine bone density was 1.066 g/cm2 between 20 and 29 years and did not change with increasing age. In the same age group, femoral neck density was 1.034 g/cm2 and it decreased steadily after the age of 40 (slope = -0.003) with an annual loss of 0.23%. Total mineral content decreased from 2.477 g in the first age group to 2.316 g in subjects 70 years old or older. This represents a net loss of 6.5% in this period. Compared with normal females from a previous study, young men have similar spine and femoral neck densities than young women until the age of 50. In women over this age, there is a steady decline in lumbar spine density and the decrease in femoral neck density is more marked than in men. Also, total mineral content is higher in young men and its 6.5% loss with age is much lesser than the 31.6% loss observed in women.

Absorptiometry, Photon↗

PubMed1990

Menstrual history as a determinant of current bone density in young athletes.

The relationship of prior menstrual irregularities and current menstrual status to the bone density of 97 young athletes was determined at seven sites using single- and dual-photon absorptiometry. Menstrual patterns were ranked on a scale of 1 to 9 in terms of their potential adverse affect on bone. Only vertebral density was significantly related to menstrual patterns (r = -.43). Women who had always had regular cycles had higher lumbar densities (1.27 g/cm2) than those with a history of oligomenorrhea/amenorrhea interspersed with regular periods (1.18 g/cm2). The lumbar density of both groups exceeded that of women who had never had regular cycles (1.05 g/cm2). Body weight became more important as a predictor variable as the severity of menstrual irregularities increased. The combination of menstrual pattern and body weight predicted 43% of the total variation in lumbar density. These data suggest that extended periods of oligomenorrhea/amenorrhea may have a residual effect on lumbar bone density.

Adolescent↗

PubMed1999

Role of risk assessment and bone density monitoring in osteoporosis.

Osteoporosis and its complications are prevalent medical problems. Of the risk factors for fractures, low bone mass is the best predictor. Measuring bone density in a person with risk factors for osteoporosis can provide important information for both patient and physician when choosing clinical interventions. For patients with the disease it is a way to assess response to drug therapy. Advances in technology have made measuring bone density safer, faster, and more practical than ever. Guidelines addressing when, where, and how the test should be done are useful when deciding how to apply this technology to patient care.

Aged↗

PubMed2004

Bone density study at the distal radius, using pQCT analysis, in Greek thalassemic patients.

BACKGROUND: Expansion of marrow spaces in thalassemia patients contributes to reduced bone density and increased risk of fractures. Peripheral quantitative computed tomography (pQCT) measures the volumetric bone mineral density (vBMD) independently in different compartments. OBJECTIVE AND METHODS: To study the regional bone structure in thalassemia, we performed pQCT (XCT-2000 Scanner, Stratec Inc.) in 57 young adult patients with beta-thalassemia major, aged 21-44 years (32 females). The vBMDs (total, trabecular, cortical + subcortical), Stress-Strain Index (SSI) and the cross-sectional area (CSA) were determined at the "4% site" of the distal radius; data were compared to reference values. RESULTS: Total vBMD, trabecular, cortical plus subcortical vBMD in thalassemics were significantly lower than in healthy adults (p<0.005). Thalassemic males had significant higher values of vBMD, SSI and CSA than females (p<0.005). CONCLUSIONS: In Greek thalassemic patients a significant reduction in bone density, associated with increased morbidity and risk of fractures, has been detected on pQCT examination.

Adult↗

PubMedDate not supplied

Evaluation of bone density in children with slipped capital femoral epiphysis.

Slipped capital femoral epiphysis (SCFE) is a condition seen during the preadolescent growth spurt, often in obese children and in children with endocrine disorders. Given that endocrine factors also play a role in bone density, a link between low bone mineral density (BMD) and SCFE was proposed. Dual energy X-ray absorptiometry (DXA) scanning of the spine and hips was performed on 12 children with SCFE and on 5 overweight children without this hip disorder. All scans were performed by the same technician using a Hologic Delphi W densitometer and were interpreted by a pediatric orthopedic surgeon certified in clinical densitometry. Z-scores were obtained using a pediatric database. Mean and standard deviation of the Z-scores were calculated, and paired t tests were used to assess differences between these subjects and the expected norm. The SCFE patients' Z-scores at each of the skeletal sites assessed (spine, femoral neck, and total hip) were greater than the mean by an average of 1 standard deviation. The control subjects' BMD was also greater than the mean. The P values were less then 0.05. These results suggest that children with SCFE do not have low BMD, but show bone density significantly greater then expected for age and sex. Although BMD is endocrinologically driven and endocrinologic abnormalities are implicated in SCFE, there appears to be no correlation between low BMD and SCFE.

Absorptiometry, Photon↗

PubMed1998

Compressive strength of interbody cages in the lumbar spine: the effect of cage shape, posterior instrumentation and bone density.

One goal of interbody fusion is to increase the height of the degenerated disc space. Interbody cages in particular have been promoted with the claim that they can maintain the disc space better than other methods. There are many factors that can affect the disc height maintenance, including graft or cage design, the quality of the surrounding bone and the presence of supplementary posterior fixation. The present study is an in vitro biomechanical investigation of the compressive behaviour of three different interbody cage designs in a human cadaveric model. The effect of bone density and posterior instrumentation were assessed. Thirty-six lumbar functional spinal units were instrumented with one of three interbody cages: (1) a porous titanium implant with endplate fit (Stratec), (2) a porous, rectangular carbon-fibre implant (Brantigan) and (3) a porous, cylindrical threaded implant (Ray). Posterior instrumentation (USS) was applied to half of the specimens. All specimens were subjected to axial compression displacement until failure. Correlations between both the failure load and the load at 3 mm displacement with the bone density measurements were observed. Neither the cage design nor the presence of posterior instrumentation had a significant effect on the failure load. The loads at 3 mm were slightly less for the Stratec cage, implying lower axial stiffness, but were not different with posterior instrumentation. The large range of observed failure loads overlaps the potential in vivo compressive loads, implying that failure of the bone-implant interface may occur clinically. Preoperative measurements of bone density may be an effective tool to predict settling around interbody cages.

Biomechanical Phenomena↗

PubMed1998

[Bone density in type 2 diabetes as related to obesity and adrenal function].

The purpose of the study was to analyse bone density in patients with noninsulin-dependent diabetes mellitus with respect to such factors as the magnitude of obesity, serum cortisol concentration and 17-ketosteroid excretion and insulinemia level. Bone density was measured by ultrasonography, insulin was determined by radioimmunoassay, and steroid level by using the method of Zimmerman. The patients had imminent and overt osteoporosis. The highest serum cortisol concentration was in groups with lower T-score significant negative correlation between cortisol and SOS index. The lowest 17-ketosteroid level was detected in the patients with the lowest T-score; a significant correlation was observed between 17-ketosteroids and BUA index. The present findings indicate an imbalance between bone protective and resorptive factors. This leads to osteopenia in patients with noninsulin-dependent diabetes mellitus despite a protective effect of obesity.

17-Ketosteroids↗

PubMed1999

Bone density in a population of long term oral contraceptive pill users does not differ from that in menstruating women.

Prevention of osteoporosis is a major public health issue. Amenorrhoeic women have lower bone density than normally menstruating women, which is related to the duration of amenorrhoea and the severity of oestrogen deficiency. Bone mineral density (BMD) in amenorrhoeic women can be improved by oestrogen replacement in the form of the combined oral contraceptive pill (COCP), so increased BMD might be an important non-contraceptive benefit of the COCP in menstruating women. Previous studies have been variably reported, but have used different methodologies for measurement of BMD. We measured BMD using the DEXA technique in long term COCP users and compared this with menstruating women who had never used the COCP. No differences in bone density were found, suggesting that the COCP does not improve bone mass in menstruating women who are adequately oestrogenised by their own ovaries.

Absorptiometry, Photon↗

PubMedDate not supplied

Long-acting hormonal contraception: assessing impact on bone density, weight, and mood.

The decline in unintended pregnancies and abortions in the United States has been attributed largely to increased use of two highly effective, hormonal contraceptive methods, depot medroxyprogesterone acetate injection (DMPA) and levonorgestrel implants (Norplant). Despite the efficacy and increasing acceptability of these long-term methods, some clinicians and women are reluctant to use them because of concerns regarding reduction in bone density with DMPA, and depressive symptoms and body weight issues with both injectables and implants. Recent multicenter experience showed no increase in depressive symptoms after 1 year's DMPA use and 2 years' Norplant use, even among users with the highest mean depressive symptom scores pre-therapy. Observational studies indicate that, as with other hormonal contraceptives and hormone replacement, DMPA does not cause significant weight gain, even during long-term use. Multicenter experience with the new soft-tubing Norplant product found an average annual pregnancy rate of <1% and a cumulative 5-year pregnancy rate of 4.2% in women weighing 70 kg or more--substantially lower than failure rates cited in the product labeling. Trends in bone density seen with DMPA appear similar to those during lactation. Subgroups of long-term DMPA users may experience a decrease in spinal bone density that appears to be reversible following discontinuation. A once-a-month injectable contraceptive combining 25 mg medroxyprogesterone acetate and 5 mg estradiol cypionate (Cyclo-Provera, Cyclofem or Lunelle), a 2-rod levonorgestrel system, and a single-rod 3-ketodesogestrel implant system may become available in the United States. Large-scale trials have established the safety, efficacy, and acceptability of Cyclo-Provera. In contrast to DMPA, users of Cyclo-Provera experience predictable, regular monthly bleeding, fewer discontinue due to bleeding-related problems. Fertility returns rapidly following discontinuation. A U.S. multicenter study is currently nearing completion.

Affect↗

PubMed1999

Menstrual history and bone density in young women.

Adequate levels of reproductive and pituitary hormones are needed for the initiation and maintenance of regular menstrual cycles as well as for the achievement of peak bone mineral density (BMD). Therefore, in the absence of direct hormone measures, menstrual history may serve as a surrogate for the adequacy of hormonal functioning and be a marker for bone status in young women. In our cross-sectional study of white college women aged 19-26 years, we examined the association of six characteristics of menstrual history with bone density at the lumbar spine and the femoral neck. To characterize associations, we used multiple linear regression models that also accounted for the contribution of body mass index, dietary calcium intake, height, level of physical activity, smoking, and alcohol use. The associations between each of the six menstrual characteristics and BMD were stronger at the lumbar spine than at the femoral neck. Age at menarche explained the most variance at both the lumbar spine (partial r2 x 100 = 5.9%) and the femoral neck (partial r2 x 100 = 2.1%). For each year that menarche was delayed, bone density was lower by -0.023 g/cm2 (p = 0.0024) at the lumbar spine and -0.0129 g/cm2 (p = 0.0565) at the femoral neck. At the lumbar spine, a higher number of lifetime menstrual cycles was also significantly associated with increased bone density (adjusted beta = 0.0010, p = 0.0052, partial r2 x 100 = 4.4%). This association was not significant after adjusting for age at menarche. Neither reproductive years (age - age at menarche) nor a history of irregular cycles (either at menarche, in the past year, or ever) was associated with bone density at either site. Menstrual function appears to affect the bone density of these young women. Studies that include measures of reproductive and pituitary hormones are needed to further explore the role of hormones in the potential link between menstrual history and bone density.

Absorptiometry, Photon↗

PubMed1993

Site of bone density measurement may affect therapy decision.

The purpose of this study was to determine whether bone mineral density (BMD) measurements at the lumbar spine and femoral neck provided comparable information to women planning to use that knowledge to help them make a decision about hormone replacement therapy. Eighty-eight healthy Caucasian women, aged 44-59 and within 0 to 5 years of menopause, participated in the study. BMD measurements were performed at the lumbar spine (L1-L4) and the femoral neck by dual energy X-ray absorptiometry (DXA). Criteria suggested by the National Osteoporosis Foundation were used to categorize women as "at risk" for osteoporosis, bone density more than one standard deviation (SD) below the young adult mean, or as "low risk", bone density at or above this level. The results indicated that 46 women would be classified into the low risk category on the basis of spinal BMD alone. However, 28 of these 46 women would fall into the at risk category when the femoral neck BMD was measured. Sixty-one percent of women informed they were at low risk on the basis of spinal BMD would be considered at risk based on femoral neck BMD. When femoral neck BMD was used as the primary risk indicator, 14% of the women classified as low risk would be at risk if spinal BMD were added. These results suggest that both lumbar spine and proximal femur measurements should be made when women are using bone density measurements as an aid in deciding whether or not to use hormone therapy in their postmenopausal years.

Absorptiometry, Photon↗