Single Photon Absorptiometry Research Articles

Identification of patients with low bone massby single photon absorptiometry and single-energy X-ray absorptiometry

Single-photon absorptiometry measurements at the radius and calcaneus have been shown in a number of prospective studies to predict the risk of all fractures as well as measurements at the spine or hip. Single-energy X-ray absorptiometry should do as well or better. These methods should be useful in selecting patients for therapy to treat or prevent osteoporosis.

A study of osteopenia in elderly diabetic patients

It is well known that IDDM cases can be complicated with osteopenia, but most of these results were reported using single photon absorptiometry. There have been few reports of diabetic osteopenia using dual energy X-ray absorptiometry (DXA), a method that is excellent for precise bone mineral measurement. Osteoarthritis and osteophytes of unknown origin in the lumbar vertebrae are often observed in elderly NIDDM patients. In this study, we examined the clinical characteristics of decreased bone mineral density (BMD) and whether anteroposterior (AP) scanning of the lumbar vertebrae (L2-L4) provides sufficient informations concerning osteopenia in elderly diabetic patients. The study was performed using DXA, which can quantify regional BMD throughout the body. The BMD in the total body and that in the lumbar vertebrae were measured by DXA (Lunar Co.) in 68 diabetics over age 60, 33 males and 35 females, mean age 68 +/- 8 yr, (mean +/- SD) and in 94 middle-aged diabetics (40 to 59), 56 males and 38 females, mean age 51 +/- 4 yr. The percentage of decrease in regional BMD in diabetic patients differed significantly by age and gender. The BMD in the head and spine especially decreased after menopause in women. However, the BMD of the leg and spine did not decrease with age in men. When the BMD of the lumbar vertebrae was plotted against the Y axis and the BMD in the total body against the X axis, the slope of the curve showed a greater increase in elderly diabetics than that in middle aged diabetics (1.8 vs 1.5) suggesting the BMD in the lumbar vertebrae has been overestimated.(ABSTRACT TRUNCATED AT 250 WORDS)

Is tubal ligation a risk factor for low bone density and increased risk of fracture?

OBJECTIVE: Osteoporosis is a major women's health problem, because it is responsible for about 1.3 million fractures in the United States each year. Estrogen deficiency is a major risk factor in the pathogenesis of osteoporosis. Recent evidence has indicated that tubal ligation may cause menstrual dysfunction and estrogen deficiency. This study examined the association between tubal ligation and bone mass in a group of elderly postmenopausal women. STUDY DESIGN: Subjects were 2215 white women ≥65 years old participating in the Baltimore center of the Study of Osteoporotic Fractures. Bone mineral density of the proximal and distal radius and the calcaneus was measured by single photon absorptiometry. Multiple regression analysis was performed to determine whether tubal ligation had an independent effect on bone density. The effect of tubal ligation on the risk of hip and osteoporotic fractures was estimated by Cox proportional hazards model. RESULTS: Women who reported a tubal ligation had lower, although not statistically significant, bone density of the radius and calcaneus. The relative risk of hip (1.05, 95% confidence limit 0.84 to 1.32) and osteoporotic fractures (1.01, 0.80 to 1.29) was not significantly increased in women with tubal ligation. CONCLUSION: We conclude that elderly women who had a tubal ligation have small changes in bone density that are not of sufficient magnitude to increase their risk of osteoporotic fractures.

Estrogen replacement therapy and fractures in older women. Study of Osteoporotic Fractures Research Group.

To determine the relation between estrogen replacement therapy and fractures. Prospective cohort study. Four clinical centers in Baltimore County, Maryland; Minneapolis, Minnesota; Portland, Oregon; and the Monongahela Valley, Pennsylvania. 9704 ambulatory, nonblack women 65 years of age or older. Estrogen use, medical history, and anthropometric data were obtained by questionnaire, interview, and examination. Appendicular bone mass was measured by single-photon absorptiometry. Incident fractures were validated by radiographic report. After adjustment for potential confounders, current estrogen use was associated with a decrease in the risk for wrist fractures (relative risk [RR], 0.39; 95% CI, 0.24 to 0.64) and for all nonspinal fractures (RR, 0.66; CI, 0.54 to 0.80) when compared with no estrogen use. Results were similar for women using unopposed estrogen or estrogen plus progestin, for women younger or older than 75 years of age, and for current smokers or nonsmokers. The effect of estrogen remained after adjustment was made for appendicular bone mass. The relative risk for hip fracture tended to be lower among current users (RR, 0.60; CI, 0.36 to 1.02) than among never-users. Estrogen was most effective in preventing hip fracture among those older than 75 years. Current users who started estrogen within 5 years of menopause had a decreased risk for hip fractures (RR, 0.29; CI, 0.09 to 0.92), wrist fractures (RR, 0.29; CI, 0.13 to 0.68), and all nonspinal fractures (RR, 0.50; CI, 0.36 to 0.70) when compared with women who had never used estrogen. Previous use of estrogen for more than 10 years or use begun soon after menopause had no substantial effect on the risk for fractures. Current use of estrogen appears to decrease the risk for fracture in older women. These results suggest that for protection against fractures, estrogen should be initiated soon after menopause and continued indefinitely.

Further increase in forearm cortical bone mineral content after discontinuation of growth hormone replacement

Growth hormone replacement of adults with childhood onset GH deficiency results in an increase in bone mineral density (BMD) after 6-12 months of GH replacement. By measuring BMD 12 months after discontinuation of GH replacement we aimed to investigate whether there is an effect of GH replacement on BMD persisting after GH has been withdrawn. BMD was measured 13 +/- 1 (mean +/- SE, range 11-16) months after discontinuation of GH replacement. Ten adults, age 23.2 +/- 1.4 (range 18.8-32.4) years, with childhood onset isolated GH deficiency (2 idiopathic, 8 irradiation induced) who had previously completed a study of the effect of 12 months of GH replacement on BMD. Forearm cortical bone mineral content (BMC) was measured using single-photon absorptiometry at the proximal site of the distal forearm. Forearm integral BMC at the ultradistal site of the forearm and bone width at both proximal and ultradistal sites of the distal forearm were measured by the same technique. Vertebral trabecular BMD was measured using quantitative computed tomography. Forearm cortical BMC was significantly greater than that measured at the time of discontinuation of GH (1.48 +/- 0.04 vs 1.44 +/- 0.05 g/cm). There was no significant change in forearm integral BMC or in vertebral trabecular BMD after discontinuation of GH. There was no significant change in bone width at proximal and ultradistal sites of the distal forearm after discontinuation of GH. After discontinuation of GH replacement the further increase in forearm cortical bone mineral content without a significant increase in forearm bone width suggests that the increase in cortical bone mineral content is due to a persisting effect of previous GH replacement, and not to further spontaneous attainment of bone mass before peak bone mass is reached. These findings emphasize the importance of continuing to monitor bone mass after the stimulus to increase bone turnover has been withdrawn.

Different rates of forearm bone loss in healthy women with early or late menopause

The aim of this study was to evaluate whether healthy women with early or late menopause have different rates of age- and menopause-related bone loss, and whether premature menopause really represents a risk factor for osteopenia. Healthy women aged from 27 to 84 years (n = 2204), with no history of fractures, were divided into two groups according to their age at menopause (AAM): group A with AAM < or = 43, and group B with AAM > or = 50 years. Bone mineral density (BMD) was measured in the distal non-dominant forearm by single-photon absorptiometry. Group B had a significantly lower average BMD than group A (group A, 0.430 +/- 0.074 g/cm2; group B, 0.419 +/- 0.081; p = 0.003); however, the average age of group A was significantly lower, and weight and height were significantly higher. When women older than 50 years of age were divided into five age-matched subgroups, BMD was significantly lower in women with AAM < or = 43 years up to 60 years; after that age this difference disappeared and, in the oldest subgroups, BMD was significantly lower in group B than in group A. Independent variables such as age, AAM and body mass index (BMI) explain about 30% of the variation of BMD, using a multiple linear regression analysis. In both groups age and BMI weighted more than AAM in determining BMD. When BMD was plotted versus either chronological age or years since menopause, women with late menopause showed a significantly faster bone loss than those with early menopause.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuclear rheumatology and metabolic bone disease. 26 October 1993

Osteoporosis is particularly prevalent in the hands of patients with rheumatoid arthritis (RA) because of the large number of peri-articular sites. Using single photon absorptiometry (SPA), we earlier demonstrated that patients with RA had a bigger deficit of hand bone mineral content (BMC) than of whole body calcium [1].

Determinants of forearm mineral density and its correlation with fracture history in women

In order to evaluate the role of single photon absorptiometry (SPA) in the prediction of osteoporotic fracture risk, 1935 women, referred for measurement of forearm mineral density (FMD) at the distal radial site, were studied by questionnaire in a cross-sectional design. There was no significant decline in FMD until the age of 47, after which there was a linear decline with age of about 1.2% per year. There was no relationship between age and FMD, or forearm mineral content (FMC), in premenopausal women. There was a fall in FMD with the number of years since menopause, after correcting for the effects of age, of approximately 0.5% per year. Body weight was positively correlated with FMC in postmenopausal women. The duration of exposure to hormone replacement therapy (HRT) was positively correlated with FMD, and the magnitude of this effect was reduced the longer the delay between the onset of the menopause and the commencement of HRT. There was no significant association of FMD with calcium intake, weight-bearing exercise, tobacco or alcohol consumption, or family history of osteoporosis. FMD was significantly lower in postmenopausal women who reported fractures after the age of 25, after correcting for age and years postmenopause. In conclusion, a low FMD is predictive of a past history of fractures and may therefore be capable of predicting future fracture risk.

Uncritical use of bone mineral density in absorptiometry may lead to size-related artifacts in the identification of bone mineral determinants

Epidemiological studies of bone mineral determinants rely heavily on measurements made with absorptiometric techniques such as single-photon absorptiometry and dual-energy x-ray absorptiometry. In general, absorptiometric data are expressed as areal densities (bone mineral density, BMD), obtained by dividing bone mineral content (BMC) by bone area or width (BA, BW). This size correction assumes that BMC and BA (BW) are directly proportional to one another, such that a 1% change in BA (BW) is matched by a 1% change in BMC. This is rarely the case, and the exact relationship depends on the population group, skeletal site, body size, instrumentation, and scanning conditions. Size adjustment determined by using predefined indexes, such as BMD and body mass index (BMI, wt/ht2), may fail to correct BMC fully for bone and body size, and may lead to spurious associations with other size-related variables such as calcium intake, energy expenditure, and grip strength. A general approach to size adjustment is described, in which BA (BW), weight, and height are incorporated in all regression models of BMC. Although BMD plays a valuable role in fracture-risk assessment and clinical management, we advocate that its use in epidemiological research be discontinued.

Efficacy and safety of two elcatonin regimens in the treatment of osteoporosis

In a 12-month, open, comparative trial, 75 female inpatients with senile osteoporosis were randomly assigned to treatment with one of two elcatonin regimens. Group 1 received elcatonin 40 IU IM every other day. Group 2 received an activate-depress-free-repeat (ADFR) regimen of calcitriol (2 μg/day orally for 7 days) as an activating agent, followed by elcatonin (40 IU/day IM for 21 days) as a depressing agent, followed by a 28-day treatment-free period. This 3-month cycle was repeated four times during the study period. Group 3 was the control group. All patients received calcium (1 g) by mouth daily. Bone mineral density (BMD) was measured in the nondominant radius by single-photon absorptiometry before treatment started and after 3, 6, 9, and 12 months of treatment. After 12 months of treatment, significantly more patients in group 1 than in the other two groups were markedly improved ( P < 0.001). Radial BMD showed a marked improvement in 50%, 24%, and 4% of patients in groups 1, 2, and 3, respectively. Mean BMD at the end of the study increased in groups 1 and 2 and decreased in group 3. Both active treatments increased mean radial BMD compared with the control group, and the every-other-day therapy produced a larger increase than the ADFR regimen. Side effects were generally mild and similar to those previously reported with calcitonin treatment.

Dairy Calcium, Bone Metabolism, and Prevention of Osteoporosis

Single-photon absorptiometry was used to measure the bone mineral content of young adults, osteoporotic patients, and age-matched controls without bone disease. A retrospective dietary survey was made to study the relationship between calcium intake and bone mineral content at different periods of life. The bone mineral content and bone mineral density of young adults are directly related to the calcium intake through milk and dairy products. Calcium intake through milk and milk products in childhood and adolescence had been significantly lower in patients than in the controls; for the later periods of life (both the 20 to 30 yr prior to the study and at the time of the study), no significant differences existed between the calcium intakes of the two groups. Adequate calcium intake also protected against increased bone resorption, as evidenced in particular by the reduced serum osteocalcin, a parameter of bone turnover. The data support the hypothesis that adequate calcium intake through milk and milk products in childhood and adolescence is a decisive marker for attaining maximum bone mass (peak adult bone mass) and for the prevention of osteoporosis. The recommended dietary allowances of calcium have been fixed to 1200 mg/d for the age group between 10 and 24 yr. However, in Germany, calcium was undersupplied by up to 50% in the diet of children and adolescents.

Hinweis auf fluoridinduzierte Effekte am Kalkaneus durch Messungen der Breitband-Ultraschallabschwächung (BUA)

We measured broadband ultrasound attenuation (BUA) of the calcaneus as well as radial (RBD) and spinal bone density (SBD) in normal and osteoporotic females (n = 188) both before treatment and after long-term fluoride therapy. RBD was measured using single photon absorptiometry of the non-dominant distal forearm (SPA) and spinal bone density (SBD) was assessed using quantitative CT (QCT). In untreated osteoporotic patients (n = 62), BUA as well as the other densitometric methods showed significantly lower values (p < 0.05) when compared to age matched controls (n = 75). Females with osteoporosis and long-term treatment with fluoride (n = 51) had both significantly higher BUA values and higher spinal bone density when compared to women with untreated osteoporosis. BUA and SBD were correlated in the entire group (r = 0.5, r < 0.0001) as well as in the subgroups of untreated (r = 0.48, p < 0.001) and fluoride-treated patients with osteoporosis (r = 0.4, p < 0.05). These results suggest that BUA provides further evidence of an osteogenic response to fluoride at peripheral weight-bearing skeletal sites such as the calcaneus.

Bone mineral content and bone density in Indian females

Bone mineral content and bone density of 234 females were measured using single photon absorptiometry technique on Computerised Bone Density Scanner-1100. The bone mineral content and bone density showed a decreasing trend with advancing age. There was no significant decrease in bone mineral content and bone density during pregnancy.

Osteoporosis and genetic influence: a three-generation study

We have studied 27 triads of mother, daughter and grandmother for possible genetic influence on distal and proximal forearm bone density, measured by single photon absorptiometry. We found a significant correlation of bone density at the proximal forearm between the mothers and grandmothers (r = 0.499, P < 0.01). There was also a weak correlation between proximal forearm bone densities of mothers and daughters (r = 0.327, P < 0.1). Significant correlations were found between the three generations for grip strength, pedometry, height and triceps skinfold thickness. There was also significant correlation between mother and grandmother for alcohol intake. There was no correlation for contraceptive pill use, smoking, dietary calcium intake, body weight or body mass index. The study concludes that, although there are similarities in bone mineral content between the three generations, genetic factors cannot be conclusively proven to be the major determinant of bone density. Lifestyle and environmental factors may have a bearing on achieving the peak bone mass and subsequent development of osteoporosis.

Distal radius fracture is an early sign of general osteoporosis: bone mass measurements in a population-based study.

To evaluate the bone mass by bone density measurements in patients with distal radius fracture, a prospective open case-control study was carried out in the county of Uppsala, Sweden, with population-based cases and controls. There were 111 patients with a distal radius fracture who were otherwise healthy and aged 53-76 years, together with 60 healthy controls of similar age, sex and menopausal status. The main outcome measures were bone mineral density (BMD) in the lumbar spine and hip measured with dual-energy X-ray absorptiometry, and in the (non-fractured) distal forearm determined by single-photon absorptiometry. It was found that at all measuring sites BMD was significantly lower in cases than in controls. The difference in the distal forearm was around 20% (p < 0.001) and in the spine and hip 5%-8% (p < 0.05-0.001). In the healthy subjects there were positive correlations (r = 0.39-0.65; p < 0.002) between the forearm BMD and that of both the spine and hip, whereas in the patients with distal radius fracture there was only a weak correlation between the forearm and spine BMD (r = 0.28; p < 0.05) and no association between the BMD of the forearm and hip (r < 0.01). It is concluded that patients with distal radius fracture who are otherwise healthy have a preferential bone loss at the distal forearm but also a generally low bone mass. Patients with fracture of the distal radius fracture should be considered for prophylactic measures against osteoporosis.

Bone mineral density predicts non-spine fractures in very elderly women. Study of Osteoporotic Fractures Research Group.

To determine the ability of bone density to predict fractures in very elderly women, we examined the association of bone density with non-spine, hip, wrist and humerus fractures in 8699 Caucasian women aged 65-79 years and 1005 women aged 80 years and older who were participants in the prospective Study of Osteoporotic Fractures. Follow-up averaged 4.9 (+/- 1.0) years after baseline measurement of appendicular bone density (single-photon absorptiometry; Osteon-Osteo Analyzer) and 2.9 (+/- 0.6) years after measurement of hip and anteroposterior lumbar spine bone density (dual-energy X-ray absorptiometry; Hologic QDR 1000) at a later examination. In general, measurements of bone density in the oldest women retained their predictive value for fractures. Among women aged 80 and over a 1 standard deviation decrease in bone density of the distal radius was associated with an increased risk of non-spine (relative risk: 1.6; 95% confidence interval: 1.3, 1.8), wrist (1.7; 1.2, 2.4) and humerus fracture (2.9; 1.8, 4.7), while a 1 standard deviation decrease in femoral neck bone density was associated with an increased risk of non-spine (1.9; 1.6, 2.4), humerus (2.4; 1.2, 4.7) and hip fracture (2.1; 1.4; 3.2). However, only trochanteric but not femoral neck fractures were associated with low bone density in these oldest women. The excess risk of fracture in women with below-median bone density was greater in those aged 80 years and over compared with the younger women: 38.4 v 20.4 per 1000 woman-years for non-spine fracture and 12.2 v 3.2 per 1000 woman-years for hip fracture.(ABSTRACT TRUNCATED AT 250 WORDS)

Osteopenia in primary biliary cirrhosis and cirrhosis of the liver in women, evaluated by dual-energy X-ray absorptiometry

To study bone involvement in primary biliary cirrhosis (PBC), we used dual-energy X-ray absorptiometry to measure bone mineral density (BMD) in Japanese women with PBC and with cirrhosis of the liver. In both groups, in each decade up to 60 years of age, the mean BMD of the lumbar spine was not significantly different from that in healthy Japanese women; however, in patients aged 60 years or more, the level was significantly lower both in the patients with PBC (P < 0.001) and in those with cirrhosis of the liver (P < 0.01). Patients with PBC were also examined by single-photon absorptiometry. The BMD of the radius in the patients with PBC was less changed than that of the lumbar vertebrae; thus, the bone changes in PBC seem to be greater in spongy than in cortical bone.

Sex differences in bone mineral density in 1653 men and women in the sixth through tenth decades of life: The rancho bernardo study

This cross-sectional population-based study examined the effect of age and sex on bone mineral density (BMD) in the elderly. BMD was measured at the spine and hip using dual-energy x-ray absorptiometry and at midshaft and ultradistal radius using single-photon absorptiometry in 672 men and 981 women aged 50-98 years. In both sexes, mean BMD levels decreased significantly with age at all sites except the male spine. In linear regression models, the slope of loss was significantly greater in women than in men at all sites except the ultradistal radius. The slope was steeper at most sites in women aged 50-59 years than in older women, 60-98 years. In both age groups, mean age-adjusted BMD levels were lower at all sites in women who were past or never users of replacement estrogen than in women who were current estrogen users. Current estrogen users generally had lower slopes of loss with age than never or past estrogen users; however, few of these differences were statistically significant. We conclude that BMD levels decrease in old age in both sexes. Continued bone loss in old age raises the possibility that intervention to retard further loss may still be warranted in the elderly.

Bone metabolism changes after transdermal estradiol dose reduction during estrogen replacement therapy: A 1-year prospective study

Twenty-four surgically menopausal women were randomly allocated to one of two transdermally-administered estrogen replacement therapies (ERT): Group A was administered Estradiol (EO TTS 0.05 mg/day for 6 months and 0.025 mg/day for the following six months and group B, E 2 TTS 0.10 mg/day for the first 6 months and 0.05 mg/day for the following 6 months. For both groups, the treatment regimen was based upon the twice-weekly application of transdermal patches to the lower abdomen for three weeks a month. Serum E 2, alkaline phosphatase (AP), osteocalcin (BGP) and urinary hydroxyproline (OHP) excretion levels were measured before the operation, at the beginning of ERT and after 6 and 12 months of treatment. Bone mineral density (BMD) in the distal regions of the forearms was measured by single photon absorptiometry at the start of the study and after 6 and 12 months. In Group A, both mean cortical and trabecular BMD had increased by, respectively, 1.53% and 2.17% after 6 months of therapy; after the second 6 months a significant decrease was observed in both parameters (2.40% and 3.62%, respectively). In Group B, mean cortical and trabecular BMD increased by 1.50% and 2.10%, respectively (significant increase in trabecular bone) after the first 6 months of treatment; after the following 6 months, these values persisted (+0.15 and −0.03%, respectively). Mean AP, OHP and BGP serum levels rose after the operation. In Group A, AP and OHP showed a significant decrease after the first 6 months (−34.90% and −30.90%), followed by an increase at the last evaluation of 22.50% and 35.50%, that reached statistical significance only for OHP. TTS 0.05 mg/day led to a significant lowering in BGP levels (−30.70 %) ( P < 0.005) with respect to post-surgical values, but they rose again by 34.50% with the lower dose (range −45.10% to + 65.20%) ( P < 0.05). In group B, both AP and OHP levels were lower than pre-treatment values after the first 6 months (38.60% and 27.60%) ( P < 0.03 and P < 0.02, respectively), remaining unchanged after treatment with 0.05 mg/day (+3.50% and −6.80%, respectively). Osteocalcin levels dropped after 6 months (−16.60%), the same values being recorded at 12 months (+3.80%). Both TTS 0.10 and 0.05 mg/day proved to be effective in counteracting postmenopausal bone loss; the dose reduction from 0.10 to 0.05 mg/day did not lead to the reactivation of bone turnover. However, the lowest E 2 dose of 0.025 mg/day wasn't effective in avoiding bone demineralization.

Interleukin 1 beta, hand and foot bone mineral content and the development of joint erosions in rheumatoid arthritis.

To assess the relationship between plasma levels of the cytokine interleukin-1 beta (IL-1 beta) and the progression of rheumatoid arthritis (RA). Two subgroups of patients, one with persistently raised ESR (>/= 50 mm/hour, n = 16, group A) and one with persistently low ESR (</= 28 mm/hour), n = 18, group I) were chosen to represent stable extremes of inflammatory activity from a prospective study of 106 patients with active RA studied over one year in a single centre. The change from baseline in hand, foot and calcaneal bone mineral content measured by single photon absorptiometry and radiographic score of joint damage was measured over 12 months, together with plasma IL-1 beta and erythrocyte sedimentation rate. Significant progression of joint damage occurred in both subgroups over one year (p < 0.0001, paired t test) though progression was significantly less in the subgroup with low ESR (p < 0.05, ANOVA). Hand and foot bone mineral content decreased by almost 10% in the subgroup with raised ESR (p < 0.005, paired t test). Stepwise linear regression analysis revealed significant independent relationships between radiographic progression over one year and plasma IL-1 beta and ESR (multiple R 0.674, F = 11.64, p < 0.0002). No such relationships were observed for changes in bone mineral content parameters. Plasma IL-1 beta levels correlate weakly with progression of joint damage though not with loss of peripheral bone density in RA. A significant reduction in peripheral bone mineral content occurs over one year in patients with active RA with persistently raised ESR.