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PubMed1998

Vertebral bone density evaluated by dual-energy X-ray absorptiometry and quantitative computed tomography in vitro.

Vertebral bone density is evaluated mainly by dual-energy X-ray absorptiometry (DXA) or quantitative computed tomography (QCT). Densitometry is used as an estimator of bone strength and forms the basis for choice of treatment. DXA expresses bone density in grams per square centimeter (area density) and QCT expresses bone density in milligrams per cubic centimeter (volumetric density). The aim of this study was to identify the differences between the two techniques, DXA and QCT, when applied to a group of female and male subjects over a wide age range. The data consisted of 221 lumbar vertebral bodies (L3 and L4) excised at autopsy. There were 90 females with a mean age of 65.6 (range 18-94) years and 131 males with a mean age of 62.0 (range 21-94) years. The vertebrae were scanned en bloc in demineralized water in Plexiglas containers with both DXA and QCT. DXA was performed using posteroanterior (PA) and lateral projection. QCT was performed in the center of each vertebra with 1 cm slice thickness. Both methods showed decreasing bone density with age. Lateral DXA showed a decrease in bone density with age from approximately 0.8 g/cm2 to approximately 0.4 g/cm2. QCT showed a decrease in bone density with age from approximately 180 mg/cm3 to approximately 30 mg/cm3. Lateral DXA bone mineral densities (BMD) were correlated with QCT densities in both females (r2 = 0.68, p < 0.00001) and males (r2 = 0.53, p < 0.00001), but females had constantly lower DXA BMDs than males at a given QCT density. QCT and width-adjusted midlateral DXA (g/cm3) were significantly correlated, with r2 = 0.64 (p < 0.00001) for females and r2 = 0.61 (p < 0.00001) for males. In conclusion, age- and gender-related differences in human vertebral bone density were shown to be dependent on the scanning method used. DXA bone mineral content (BMC) and BMD showed that females had lower values than males at all ages. When the "volumetric" DXA measurements and QCT were used, the females had the highest densities in the younger decades and males had the highest densities in the oldest decades. Finally, the area density (BMD) measured by DXA was lower in females than in males with identical QCT volumetric bone densities.

Absorptiometry, Photon↗
PubMed1978

Bone density and the carpal tunnel syndrome.

Bone density was studied in ten patients before and after release of an idiopathic carpal tunnel syndrome. A corticomedullary ratio was measured at the mid-point of the metacarpals and proximal phalanges of both hands. There was a significant increase in the mean bone density over the period of observation in the thumb and middle finger metacarpals and in the index, middle, and ring finger proximal phalanges of the operated hand. There was no significant increase in the density of either metacarpal or proximal phalanx on the non-operated side. Release of the carpal tunnel syndrome provides not only symptomatic relief but also leads to increased bone density.

Adult↗
PubMed2004

Artifactual reduction in bone density as a result of technetium-99m MDP for bone scanning: report of two cases.

We present two patients in whom marked changes in dual-energy X-ray absorptiometry (DXA)-measured bone mineral density were found to be the result of prior administration of technetium-99m methylene diphosphonate (MDP) for bone scanning. In patient 1, an artifactual 50% decrease in lumbar spine and 19% decrease in left total hip bone density over a 14-mo period was the result of technetium-99m injection 3 h before the second bone density measurement. In patient 2, a dramatic increase in bone density at 6 mo was the result of artifactual reduction in bone density on the baseline study as a result of technetium-99m injection 2 h earlier. Clinicians and technologists should be aware that technetium-99m used for bone scanning could cause artifactual reduction in DXA-measured bone mineral density.

Absorptiometry, Photon↗
PubMed1993

The effect of postmenopausal estrogen therapy on bone density in elderly women.

BACKGROUND: Estrogen therapy prevents bone loss in postmenopausal women who take it early in the postmenopausal period. The risk of fracture is highest much later in life, however. We studied whether bone mass in elderly women was affected by earlier estrogen use and how long women needed to take estrogen for it to have a beneficial effect on bone density later in life. METHODS: In 1988 and 1989, we measured bone mineral density at the femur, spine, shaft of the radius, and ultradistal radius in 670 white women in the Framingham Study cohort (mean age, 76 years; range, 68 to 96). These women had been followed prospectively through menopause and had been asked repeatedly about estrogen therapy. After excluding women who began taking estrogen after a fracture, we investigated whether postmenopausal estrogen therapy affected bone density; in these analyses we adjusted for age, weight, height, cigarette smoking, physical activity, and age at menopause. RESULTS: A total of 212 women (31.6 percent) had received estrogen therapy (mean estimated duration of treatment, 5 years). Only women who had taken estrogen for 7 to 9 years or for 10 or more years had significantly higher bone mineral density than women who had not taken estrogen (7 to 9 years of treatment, P < 0.05 at sites in the femur and the spine; > or = 10 years, P < 0.05 at all sites except the spine). In the women less than 75 years of age who had taken estrogen for seven or more years, the bone density was, averaging all sites, 11.2 percent greater than in women who had never received estrogen. Among women 75 years of age and older in whom the duration of therapy was comparable, bone density was only 3.2 percent higher than in women who had never taken estrogen. CONCLUSIONS: For long-term preservation of bone mineral density, women should take estrogen for at least seven years after menopause. Even this duration of therapy may have little residual effect on bone density among women 75 years of age and older, who have the highest risk of fracture.

Age Factors↗
PubMed1988

Vertebral bone density in children: effect of puberty.

To determine changes in bone density during growth, trabecular vertebral density and an index of spinal cortical bone were measured with quantitative computed tomography in 101 children. The children were divided by age into three groups: prepubertal, indeterminate, and pubertal. Compared with prepubertal children, pubertal adolescents had significantly higher trabecular bone density and more compact bone in the spine (P less than .001). After controlling for puberty, vertebral bone density failed to correlate significantly with age, sex, weight, height, surface area, and body mass index. The results indicate that bone density increases markedly during puberty.

Adolescent↗
PubMed1994

Tooth loss and skeletal bone density in healthy postmenopausal women.

Associations between dental status and skeletal bone density were investigated in a group of 329 healthy postmenopausal women with normal bone density. Bone mineral density (BMD) of the lumbar spine, femoral neck and distal radius were measured by dual- or single-photon absorptiometry. Number of teeth remaining were counted and presence of complete dentures noted by a nurse practitioner. Forty-eight women (15%) wore a complete maxillary and/or mandibular denture: 22(7%) were completely edentulous and an additional 26 (8%) had one edentulous ridge. Among women without complete dentures (n = 281), significant positive linear relationships were observed between number of teeth and BMD at the spine (p < 0.05) and radius (p < 0.01), controlling for years since menopause, pack-years of smoking, education and body mass index. BMD did not differ between the groups with and without dentures. However, women who acquired dentures after the age of 40 years had significantly lower mean spinal and radial BMD than women who acquired dentures at age 40 years or earlier (at the radius, 0.584 +/- 0.015 v 0.630 +/- 0.017 g/cm2, p < 0.05; at the spine, 1.043 +/- 0.031 v 1.124 +/- 0.029 g/cm2, p = 0.05). In linear regression analysis, significant independent correlations were found among all women (n = 329) between number of teeth and age (partial r = -0.19, p < 0.001), pack-years of cigarette use (partial r = -0.23, p < 0.001) and years of education (partial r = +0.11, p < 0.05). These associations between dental status and BMD support the hypothesis that systemic bone loss may contribute to tooth loss.

Adult↗
PubMedDate not supplied

Moderate alcohol consumption and bone density among postmenopausal women.

Chronic alcohol abuse is associated with low bone density and high risk of fracture. However, moderate alcohol consumption may help to maintain bone density in postmenopausal women by increasing endogenous estrogens or by promoting secretion of calcitonin. We conducted a prospective study among a sample of 188 white postmenopausal women (ages 50-74) from the Nurses' Health Study who participated in a health examination between 1993 and 1995 that included bone density assessments of the lumbar spine and proximal femur. Long-term alcohol intake was calculated as the average of the 1980 and 1990 measures from a food frequency questionnaire. Women who consumed 75 g or more of alcohol per week had significantly higher bone densities at the lumbar spine compared with non-drinking women (0.951 vs. 0.849 g/cm2, p = 0.002) after adjusting for age, body mass index (kg/m2), age at menopause, use of postmenopausal estrogens, and smoking status. Further adjustment for physical activity and daily intakes of calcium, vitamin D, protein, and caffeine did not alter the results. We also observed a linear increase in spinal bone density over increasing categories of alcohol intake (p = 0.002), suggesting that alcohol intakes of less than 75 g/week may also be of benefit. This positive association was observed among both current users and never users of postmenopausal estrogens. In contrast to the lumbar spine, femoral bone density was not higher among drinkers compared with nondrinkers, although density did increase among drinkers with increasing level of alcohol consumption. Further research is needed to determine whether moderate alcohol consumption can help to protect against spinal fractures in postmenopausal women. This finding must also be evaluated within a larger scope of the risks and benefits of alcohol on heart disease, breast cancer, and hip fractures.

Aged↗
PubMed1997

The effect of calcium supplementation on bone density during lactation and after weaning.

BACKGROUND: Women may lose bone during lactation because of calcium lost in breast milk. We studied whether calcium supplementation prevents bone loss during lactation or augments bone gain after weaning. METHODS: We conducted two randomized, placebo-controlled trials of calcium supplementation (1 g per day) in postpartum women. In one trial (the study of lactation), 97 lactating and 99 nonlactating women were enrolled a mean (+/-SD) of 16+/-2 days post partum. In the second trial (the study of weaning), 95 lactating women who weaned their infants in the 2 months after enrollment and 92 nonlactating women were enrolled 5.6+/-0.8 months post partum. The bone density of the total body, lumbar spine, and forearm was measured at enrollment and after three and six months. RESULTS: The bone density of the lumbar spine decreased by 4.2 percent in the lactating women receiving calcium and by 4.9 percent in those receiving placebo and increased by 2.2 and 0.4 percent, respectively, in the nonlactating women (P<0.001 for the effect of lactation; P= 0.01 for the effect of calcium). After weaning, the bone density of the lumbar spine increased by 5.9 percent in the lactating women receiving calcium and by 4.4 percent in those receiving placebo; it increased by 2.5 and 1.6 percent, respectively, in the nonlactating women (P<0.001 for the effects of lactation and calcium). There was no effect of either lactation or calcium supplementation on bone density in the forearm, and there was no effect of calcium supplementation on the calcium concentration in breast milk. CONCLUSIONS: Calcium supplementation does not prevent bone loss during lactation and only slightly enhances the gain in bone density after weaning.

Adult↗
PubMed1995

[Measuring bone density--applications, critique, consequences].

The supporters of bone density measurement or osteodensitometry claim that it is possible to reduce the frequency of fractures if a lack of systemic bone mineral content is detected in time. Important topical points of criticism are brought forward. Meaningful clinical use is only possible if reference data referring to population are accepted, and standardised quality assurance is safeguarded. Densitometrical methods do not guarantee sufficient prognostic data neither for diagnostic purposes nor for estimating the risk of fracture. In addition, they are not reliable enough for assessment of a treatment. The compensation of costs by statutory health insurance for bone density measurements as therapeutic aid should be restricted to regular controls of bone density after having diagnosed a pathological fracture, and to controls of certain secondary forms of osteoporosis.

Adult↗
PubMed1992

Excess androgenicity only partially explains the relationship between obesity and bone density in premenopausal women.

Obese subjects have increased bone density relative to non-obese subjects yet this relationship is not fully understood. We examined whether alterations in sex hormones or binding proteins might explain the effect of obesity on osteoporosis in 83 premenopausal women from the San Antonio Heart Study, a population-based study of diabetes. We measured total testosterone, oestradiol, oestrone, sex hormone binding globulin (SHBG), and serum dehydroepiandrosterone sulphate (DHEA-SO4). Bone density was assessed by a Hologic dual photon absorptometer. Lumbar spine and femoral neck density were positively correlated with body mass index (BMI). In addition, femoral neck density was positively correlated with DHEA-SO4. BMI was negatively correlated with SHBG. After adjustment for sex hormones by multiple linear regression a positive association between bone density and obesity still exists suggesting that the association between obesity and bone density is at least partially independent of sex steroids in premenopausal women.

Adult↗
PubMed1994

The bone density of female twins discordant for tobacco use.

BACKGROUND: Smoking is recognized as a risk factor for vertebral, forearm, and hip fractures. Since bone density is an important determinant of bone strength, we conducted a study to ascertain whether a deficit in bone density is associated with tobacco use and, if so, to identify the responsible mechanisms. METHODS: We conducted a cross-sectional study of bone density at the lumbar spine and the femoral neck and shaft in 41 pairs of female twins (21 monozygotic pairs), 27 to 73 years of age (mean, 49), who were discordant for at least 5 pack-years of smoking (mean, 23; maximum, 64). Bone density was measured by dual-photon absorptiometry. The difference in bone density between the members of a pair was expressed as a percentage of the mean value for the pair. RESULTS: For every 10 pack-years of smoking, the bone density of the twin who smoked more heavily was 2.0 percent lower at the lumbar spine (P = 0.01), 0.9 percent lower at the femoral neck (P = 0.25), and 1.4 percent lower at the femoral shaft (P = 0.04). These results were not confounded by measured lifestyle factors. In the 20 pairs who were discordant by 20 or more pack-years (mean, 35), the (mean +/- SE) within-pair differences in bone density at the three sites were 9.3 +/- 3.1 percent (P = 0.008), 5.8 +/- 2.9 percent (P = 0.06), and 6.5 +/- 3.2 percent (P = 0.05), respectively. Smoking was associated with higher serum concentrations of follicle-stimulating hormone (P = 0.02) and luteinizing hormone (P = 0.03) and lower serum concentrations of parathyroid hormone (P = 0.05). Differences in spinal bone density between members of a pair were associated with differences in the serum concentrations of parathyroid hormone (P = 0.01) and calcium (P = 0.05) and urinary pyridinoline excretion (P = 0.06), a marker of bone resorption. CONCLUSIONS: Women who smoke one pack of cigarettes each day throughout adulthood will, by the time of menopause, have an average deficit of 5 to 10 percent in bone density, which is sufficient to increase the risk of fracture.

Adult↗
PubMed2005

Changes in bone density and metabolism in pregnancy.

OBJECTIVE: The impact of pregnancy on maternal bone density remains unclear. As a prerequisite to investigate the pathophysiology of gestational bone metabolism, we sought to document the changes in bone metabolism biochemistry in conjunction with those in selective trabecular/cortical osteodensitometry between early and late pregnancy. METHODS: A prospective, controlled study in a university hospital was conducted with 43 healthy women, 34 of them during uneventful pregnancy. The main outcome measures are trabecular and cortical bone density measured in the first and third trimesters using peripheral quantitative computed tomography in conjunction with a panel of bone metabolism parameters, including blood parathyroid hormone, calcitonin, osteocalcin, skeletal alkaline phosphatase, and the urinary desoxypyridinoline/creatinine ratio. RESULTS: Cortical bone density was unaffected by pregnancy. Trabecular bone density changes showed wide interindividual variation, ranging from +1.3 to -20.7% per year, identified as fast losers (less than -3%) and slow losers (more than -3%). Serum osteocalcin levels were lower in slow versus fast bone losers in both trimesters (first: P=0.02, third: P=0.02) and were the only independent parameter to differentiate between fast and slow losers. CONCLUSIONS: Our data suggest that wide interindividual variation and the failure to provide a separate measure of trabecular bone density account for the conflicting evidence in earlier reports. Serum osteocalcin concentration during the first trimester distinguishes between fast and slow losers of trabecular bone and should be evaluated in future studies as predictor for later bone loss (osteoporosis).

Absorptiometry, Photon↗
PubMed2005

Bone density after completion of growth hormone treatment for growth failure.

Bone density was determined by DEXA scan at completion of growth hormone (GH) therapy in 56 (female/male 9/47) young adults who received GH therapy for growth failure. The z-scores for total and L2-4 bone density were determined from standard curves for age. There was no association of BMD with size. The z-scores for total body and L2-4 bone density indicated a disproportionate number with z-score < -1 SD. Thirty-four percent had z-score < -1 compared to the expected 17% for a normal distribution. The markers of bone metabolism, duration of therapy, initial or final stimulated GH levels, adult height, and percentage body fat did not define those who had decreased bone density. Percentage body fat was inversely associated with stimulated GH levels. We conclude that children who have completed GH therapy may have decreased bone density at completion of therapy and that the GH response to secretagogues does not define this group. The significance of this finding will require additional cross-sectional and longitudinal studies.

Absorptiometry, Photon↗
PubMed2001

All patients with inflammatory bowel disease should have bone density assessment: pro.

Bone loss is a common problem for individuals with inflammatory bowel disease. Corticosteroids play an important role in the development of osteoporosis in these patients; however, active disease and longer disease duration also appear to increase the risk of osteoporosis. Given the current burden of osteoporosis, bone mineral density is recommended.

Adolescent↗
PubMed2006

[Bone density change simulation by using internal bone remodeling theory and finite element method].

This paper presents an investigation on the effect of external force on internal bone remodeling by adopting the internal bone remodeling theory in conjunction with finite element method. After the border data are picked from a tomogram, a two-dimensional bone model is formed. The bone remodeling results are obtained by use of the finite element software Ansys. The results agree well with the real structure of bone in some degree, thus demonstrating the validity of the proposed method.

Biomechanical Phenomena↗
PubMed1991

A cross-sectional study of the effects of long-term percutaneous hormone replacement therapy on bone density.

The effect of hormone implants on the bone density of postmenopausal women was studied in 110 patients (mean age 54.7 years; mean menopausal age 8.6 years, range 2-30) who had received hormone replacement in the form of estradiol (50-75 mg) and testosterone (100 mg) pellets at 6-month intervals for 2-24 years (mean 5.2). They were compared with 254 untreated women (mean age 55.0 years; mean menopausal age 6.8 years, range 1-37). The bone density at the spine, measured by quantitative digital radiography, was 1.123 grams hydroxyapatite (gHa)/cm2 in the treated group and 0.951 gHa/cm2 in the controls (P less than .0001). The total bone density at the proximal femur was 1.002 gHa/cm2 in the treated group, compared with 0.914 gHa/cm2 in the controls (P less than .0001). There were significant differences in the density of the trochanteric, intertrochanteric, and neck areas of the proximal femur as well as the Ward triangle (all P less than .0001). These differences became significant from the age of 55 at the neck of the femur, Ward triangle, and lumbar spine, and from age 60 for all other values. Subcutaneous estradiol and testosterone prevent postmenopausal osteoporosis and maintain normal bone density for as long as treatment is continued.

Adult↗