Calcium supplementation and bone loss in middle-aged women.

This 4-y study investigated the effects of a calcium carbonate supplement on bone loss in 169 women aged 35-65 y, randomly assigned to placebo and treatment (1500 mg Ca/d) groups in a double-blind design. Bone mineral content (BMC) and width (W) were measured bilaterally on the radius, ulna, and humerus. BMC and BMC/W loss rates were consistently lower in treatment than in control subjects. Loss was significantly reduced in the left and right humerus and the right radius. In premenopausal subjects, only left humerus BMC loss was significantly reduced by Ca supplementation. In postmenopausal treatment subjects, BMC and BMC/W bone loss was reduced in all 12 (bilateral radius, ulna, and humerus) of the bone variables measured, 5 at p less than 0.01 and 2 at p less than 0.05. Ca supplementation counteracted a large portion of the additional bone loss attributable to menopause in this population.

Comparison of bone density measurements from different skeletal sites.

Absorptiometric measurements from multiple sites in 212 consecutive patients were examined to determine the interrelationships among bone mineral content values obtained from the lumbar spine, hip, and forearm. Dual photon absorptiometry was used to examine the spine, femoral neck, Ward's triangle, and greater trochanter while the radius and ulna were studied with single photon absorptiometry. All studies were performed on the same day. Concurrent measurements were available for the spine and hip in 197 patients, for the spine and forearm in 151 patients, and at all three sites for 146 patients. Variable degrees of correlation were found among the mineral content values from the six sites, with r values ranging from 0.40 to 0.93. The femoral neck and Ward's triangle showed the highest degree of correlation (r = 0.93); the ulna and lumbar spine demonstrated the poorest correlation (r = 0.40). Relationships between distant anatomic sites exhibited a large amount of variability (large standard error of the estimate) even when highly correlated. Useful predictions of bone mineral content could be obtained only for sites in close proximity. These results suggest that bone mineral content determinations in the upper extremities by single photon absorptiometry may not be useful for predicting mineralization in clinically more significant areas such as the lumbar spine and hip.

Vertebral and peripheral bone mineral content by photon absorptiometry.

Dual photon absorptiometry with 153Gd was used to determine the bone mineral content of the lumbar spine of 46 subjects. The bone mineral content of the radius and ulna were measured on these same subjects using single photon absorptiometry. The bone mineral content at the peripheral sites was not a very accurate indicator of absolute bone mineral content in the spine. However, the rate of bone loss with age was greater in the peripheral bones than in the spine. Measurement sites on the appendicular skeleton may provide a more sensitive indication of age changes in bone mineral content throughout the skeleton than would sites on the axial skeleton.

Effect of arm orientation on bone mineral mass and bone width measured using the Cameron-Sorenson technique.

Bone mineral content and bone width were measured as the distal and midshaft locations in the right radius and ulna with the arm in different orientations. The values of mineral content, width, and the ratio of bone mineral content divided by width, determined at each bone site were compared to establish the effect of orientation. Seven orientations were studied, two of which involved rotations of the forearm and five of which involved rotations of the upper arm about the axis of the forearm. Rotation of the forearm was found to affect the values of one or more of the measured quantities at all of the sites. Orientation of the upper arm was found to affect the values of all quantities at the midshaft radius, but not to affect the values of any of the quantities at the other sites.

Regulation of bone formation by applied dynamic loads.

UNLABELLED: In studies on a functionally isolated avian-bone preparation to which external loads could be applied in vivo, we determined the following information. Removal of load-bearing resulted in substantial remodeling endosteally, intracortically, and, to a lesser extent, periosteally. Since the balance of this remodeling was negative, bone mass declined. It therefore appears that functional load-bearing prevents a remodeling process that would otherwise lead to disuse osteoporosis. Four consecutive cycles a day of an externally applied loading regimen that engendered physiological strain magnitudes but an altered strain distribution prevented remodeling and was thus associated with no change in bone mass. A small exposure to, or the first effect of, a suitable dynamic strain regimen appears to be sufficient to prevent the negatively balanced remodeling that is responsible for disuse osteoporosis. Thirty-six 0.5-hertz cycles per day of the same load regimen also prevented intracortical resorption but was associated with substantial periosteal and endosteal new-bone formation. Over a six-week period, bone-mineral content increased to between 133 and 143 per cent of the original value. Physiological levels of strain imposed with an abnormal strain distribution can produce an osteogenic stimulus that is capable of increasing bone mass. Neither the size nor the character of the bone changes that we observed were affected by any additional increase in the number of load cycles from thirty-six to 1800. CLINICAL RELEVANCE: The results of this experiment must be considered in relation to the type and duration of the non-physiological loads that were imposed.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone-mineral content of the femoral neck and spine versus the radius or ulna.

The interrelationship between the bone-mineral content of sites on the radius or ulna and that of the femoral neck and lower thoracic vertebrae of twenty-four human skeletons was determined. The average correlation coefficients, -/r, were 0.82 and 0.57. Regression analysis showed that the bone-mineral content of the radius provides a good estimate of the bone-mineral content of the femoral neck (standard error of estimate approximately 16 per cent). Multiple regression analysis using the age of the subject and the bone-mineral content of the radius provides an equation with a similar standard error of estimate for the vertebrae.

Bone mineral content of the forearm in healthy Dutch women.

Single energy photon absorptiometry is a reliable technique for assessing the bone mineral content (BMC) of cortical bone in the forearm. It can also be used for BMC measurement in the ultradistal part of the forearm, where there is a considerable proportion of trabecular bone. The results of a BMC survey at both sites in healthy Dutch women, aged 26-75 yr, are reported, and the differences and changes with age are discussed. The technique offers possibilities for a rational screening programme in post-menopausal women, because of its high precision, low radiation dose, speed and low cost. The validity of the ultradistal measurement for the detection of abnormally fast bone mineral loss from trabecular bone in the individual patient has yet to be proven.

Measurement of bone mineral content in the human fetus by photon absorptiometry.

A photon absorptiometer designed to measure the bone mineral content (BMC) of the radius and ulna in premature or term babies was used to examine 34 forearm specimens obtained from 25 male and 9 female babies dying before or up to 13 weeks after birth. Gestational age, foot and crown-heel lengths and birth weight were recorded. Radiographic measurements showed that the midshaft of the radius can be located with a positioning error of +/- 1.28 mm (+/- 2 S.E.E.) from the distance between the distal ulnar styloid process and proximal tip of the olecranon, both of which can be palpated in vivo. Scanning at 5 sites showed that effects of positioning errors on BMC measurements are least at the midshaft site. Subsequent measurements of the ash weight of sections of the radius and ulna, centred on the midshaft of the radius, showed that ash weight/unit length can be estimated with a standard error 2.99 mg/cm from scan data.

[Physiological changes of mineral content of radius and ulna in relation to age and sex (author's transl)]. / Physiologische Anderung des Mineralgehalts von Radius und Ulna in Abhängigkeit von Lebensalter und Geschlecht

The mineral content of the radius and the ulna was measured in 773 persons using 125J photon absorptiometry. Statistical evaluation of the data has provided normal values of mineral content of the forearm bones in men and women between the ages of 15 and 90 years. The course of the mineral content curve is discussed in relation to age and sex.

[Mineral content of the peripheral skeleton in patients with diabetes mellitus ]. / Ergebnisse der Bestimmung des Mineralsalzgehaltes am peripheren Skelett bei Patienten mit Diabetes mellitus.

In order to determine the effect of diabetes mellitus on bone mineral content, measurements with the iodine 125 isotope method of Cameron were carried out in the distal ulna and calcaneus of 40 patients. 38% of female and 20% of male diabetic patients showed abnormally low values. The most severe changes were found in patients with complications of diabetes. There was a correlation between the duration of the diabetes and the severity of the mineral loss.

[Physiological increase in the mineral content of the radius and ulna during growth (author's transl)]. / Physiologischer Anstieg des Mineralgehalts von Radius und Ulna im Wachstumsalter.

Bone mineral estimations were carried out in 273 normal youngsters aged 6 to 18 years using a 125I photon absorption technique. Measurements were carried out at two points on the radius and ulna. Normal values for different ages were calculated for both sexes. Statistical analysis of the data, together with measurements obtained from 773 adults, has shown that the curve derived from children and adolescents merges smoothly with that for adults.

[Radiologic studies of the correlation between the mineral content of the peripheral and axial skeleton]. / Radiologische Untersuchungen zur Korrelation des Mineralgehaltes zwischen peripherem und Stammskelett.

Estimations of mineral content of normal human skeletons using three radiological methods have led to the following conclusions: 1. Bone density of vertebral bodies increases from T.6 to L.5. Average values for thoracic and lumbar vertebrae are 0.71 and 0.88 g./cm2. 2. There is no linear correlation between the mineral content of an easily accessible peripheral bone and of the vertebrae. 3. The method for bone mineral estimation, using thulium170, which was developed in Dresden, can be used for the peripheral and central skeleton. 4. 125-photon absorption us useful for measurements on the peripheral skeleton, where it is the most elegant and accurate method. It is, however, useless for measurements of the central skeleton.