Single Photon Absorptiometry Research Articles

Plasma leptin concentrations are associated with bone mineral density and the presence of vertebral fractures in postmenopausal women.

Although total fat body mass (FM) is considered to be one of the major determinants of bone mass, the mechanism by which FM and bone mass are positively correlated remains unclear. Leptin, the product of the obese (ob) gene, is secreted from adipocytes and its plasma levels are known to be positively correlated with %fat (FM divided by total body weight). There is recent evidence suggesting that leptin directly stimulates osteoblastic differentiation. Thus it is possible that the anabolic action of this hormone on bone may participate in the positive correlation between FM and bone mass. In this study, we analysed the relationships between either plasma leptin levels or %fat vs. bone mineral density (BMD) values as well as the presence of vertebral compression fractures, and evaluated whether or not plasma leptin levels were associated with BMD or bone fragility in a manner independent of FM. One hundred and thirty-nine postmenopausal women (age 48-78 years, mean 62.5), who visited our outpatient clinic for the evaluation of osteoporosis. Plasma concentrations of leptin after an overnight fast were measured by radioimmunoassay. BMD values were measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine, femoral neck and whole body. Distal one-third of radius BMD was measured by single photon absorptiometry (SPA). Vertebral fractures were assessed by lateral thoracic and lumbar spine radiographs. Although neither plasma leptin levels nor %fat correlated with age, there was a significant positive correlation between plasma leptin levels and %fat (r = 0.563, P < 0.001). Plasma leptin levels were significantly and positively correlated with BMD values at all skeleton sites measured, and multiple regression analysis revealed that this positive relationship was still observed with BMD values of the femoral neck and of the whole body, even after %fat and age were taken into account. Moreover, plasma leptin levels but not %fat were significantly lower in women with vertebral fractures than in those without fractures. When multiple logistic regression analysis was performed with either plasma leptin value or %fat employed as independent variables, plasma leptin values but not %fat were selected as an index affecting the presence of vertebral fractures. Our study showed that plasma leptin levels but not %fat are associated with BMD and the presence of vertebral fractures in postmenopausal women, suggesting that circulating leptin might play a physiological role in maintaining bone mass as well as better bone quality.

Determinants of bone mineral density and spinal fracture risk in postmenopausal Japanese women.

The present study analyzed the factors that determine bone mineral density (BMD) and predict spinal fracture risk in postmenopausal Japanese women. Two hundred and five postmenopausal Japanese women aged 48-84 years (mean age 64 years) were enrolled in the cross-sectional study. BMD of the lumbar spine, femoral neck and total body as well as body composition were measured by dual-energy X-ray absorptiometry (DXA). Mid-radial BMD was measured by single-photon absorptiometry. We also determined serum levels of insulin-like growth factor (IGF)-I, IGF binding protein-2, -3 and osteocalcin as well as urinary levels of pyridinoline (Pyr), deoxy-Pyr (D-Pyr) and growth hormone. Multiple regression analysis revealed that lean body mass (LBM) was positively correlated with BMD at all sites. In contrast, femoral neck BMD was highly related to fat mass as well as LBM, although fat mass was not an independent correlate of total body and mid-radial BMD. LBM and urinary D-Pyr were crucial determinants at all sites except the mid-radius in stepwise regression analysis. Fat mass and serum IGF-I were determinants of femoral neck and mid-radial BMD, respectively. In terms of reproductive history, parity affected lumbar BMD. Factors affecting BMD differed according to the site. On the other hand, lumbar BMD as well as serum levels of IGF-I and albumin were selected as predictors of spinal fracture risk in multiple logistic regression analysis. Lumbar BMD, serum IGF-I and LBM were selected in women with lumbar BMD above 0.727 g/cm2. In conclusion, the present study indicates that LBM is a more important determinant of BMD than fat mass at any site except the femoral neck. Age, serum IGF-I and urinary D-Pyr were also determinants of BMD, dependent on the regions measured. Lumbar BMD and LBM as well as serum levels of IGF-I and albumin were useful markers which predicted the risk of osteoporotic spinal fractures in postmenopausal Japanese women.

Bone metabolism and body composition in Japanese patients with active acromegaly.

Skeletal involvement is a common clinical feature in acromegalic patients. Although several recent reports are available concerning bone mineral density (BMD) in acromegaly, the controversy still exists as to whether BMD of acromegalic patients is increased or not. The present study was performed to examine biochemical bone metabolic indices and BMD as well as body composition in 26 Japanese patients with active acromegaly and 26 control subjects matched for age, sex, race and height in a cross-sectional study. BMD of the lumbar spine and femoral neck, as well as body composition, was measured by dual-energy X-ray absorptiometry. Mid-radial BMD was measured by single-photon absorptiometry. We also determined serum levels of IGF-I, IGFBP-3 and osteocalcin (OC) as well as urinary levels of deoxy-pyridinoline (D-Pyr) and CrossLaps. Percent lean body mass was increased and percent fat mass was decreased in the acromegalic patients compared to control subjects. Serum levels of OC, as well as urinary levels of D-Pyr and CrossLaps, were significantly higher in acromegalic patients compared to control subjects (9.8 +/- 1.2 vs. 5.7 +/- 0.77 for OC; 11.8 +/- 1.66 vs. 5.0 +/- 0.49 for D-Pyr; 437.6 +/- 68.4 vs. 156.5 +/- 39.6 for CrossLaps). Z scores of BMD at mid-radius as well as lumbar spine and femoral neck were significantly higher in acromegalic patients compared to control subjects (1.086 +/- 0.311 vs. -0.060 +/- 0.274 for mid-radius; 1.022 +/- 0.280 vs. 0.319 +/- 0.165 for lumbar spine; 1.292 +/- 0.347 vs. 0.232 +/- 0.264 for femoral neck). The present study revealed that a decrease in percent fat mass and an increase in percent lean body mass were observed in Japanese patients with active acromegaly. Bone mineral density at all sites and bone metabolic markers were also increased in acromegaly. The present findings provide additional evidence that the GH/IGF-I axis might play an important role in the maintenance of bone mass as well as the regulation of body composition in Japanese adults.

Bone mass and breast cancer risk in older women: differences by stage at diagnosis.

Older women with low bone mineral density (BMD) have a decreased incidence of breast cancer. It is not known whether this association is confined to early-stage, slow-growing tumors. We prospectively studied 8905 women who were 65 years of age or older during the period from 1986 through 1988 and had no history of breast cancer. At study entry, we used single-photon absorptiometry to measure each woman's BMD at three skeletal sites: the wrist, forearm, and heel. The women were followed for a mean of 6.5 years for the occurrence of breast cancer. All statistical tests were two-sided. During 57 516 person-years of follow-up, 315 women developed primary invasive or in situ breast cancer. Multivariate analyses that adjusted for age, obesity, and other covariates revealed that the risk of breast cancer for women in the highest quartile of BMD for all three skeletal sites was 2.7 (95% confidence interval [CI] = 1.4 to 5.3) times greater than that for women in the lowest quartile at all three skeletal sites. The magnitude of increased risk associated with high BMD differed by the stage of disease at diagnosis and was greater for more advanced tumors (relative risk [RR] for TNM [i.e., tumor-lymph node-metastasis] stage II or higher tumors = 5.6; 95% CI = 1.2 to 27.4) than for early-stage disease (RR for in situ/TNM stage I tumors = 2.2; 95% CI = 1.0 to 4.8). Elderly women with high BMD have an increased risk of breast cancer, especially advanced cancer, compared with women with low BMD. These findings suggest an association between osteoporosis and invasive breast cancer, two of the most prevalent conditions affecting an older woman's health.

The Effects of Region-Specific Resistance and Aerobic Exercises on Bone Mineral Density in Premenopausal Women

Epidemiological, cross-sectional, and prospective studies strongly suggest that exercise has beneficial effects on bone mass in premenopausal women. We prospectively compared the effects of resistance or aerobic exercises on regional bone mass in premenopausal active duty military women ranging in age from 19 to 40 years. Subjects were assigned, by preference, to a resistance exercise group or an aerobic exercise group and instructed to exercise at least 30 minutes per day, three times per week, for a period of 1 year. Bone mineral density (BMD) was measured by dual photon absorptiometry at the lumbar spine and femoral neck and by single photon absorptiometry at the mid radius at baseline, 6 months, and 12 months. BMD increments during the study were statistically significant at all sites in both exercise groups. Comparisons between the groups showed that after 12 months, BMD increased similarly in the lumbar spine (2.2% resistance vs. 1.8% aerobics, p = not significant) but more in the resistance group in the femoral neck (5.0% vs. 2.7%, p < 0.001) and the mid radius (7.8% vs. 6.7%, p < 0.05). Both resistance and aerobic exercises increase regional bone mass, particularly cortical bone mass, in premenopausal women. Resistance work appears to have a slightly greater effect on cortical bone than aerobics alone. A combination of aerobics and resistance exercises, therefore, may be a useful strategy for increasing peak bone mass in premenopausal women.

Relationships between third metacarpal bone parameters and surface strains.

The relationships were explored between measurements of bone quality, size (quantity) and shape, and strain data collected during treadmill exercise at 4 and 12 m/s from the third metacarpal bones of 6 yearling and 6 mature Thoroughbred racehorses. Peak strains in yearling and mature Thoroughbred horses during exercise were related to the size and shape of the third metacarpal bone. The peak strains were significantly lower in horses with a greater cross-sectional area of bone and with a greater proportion of the bone in the dorsal cortex. There was no consistent relationship between peak strains and bone quality assessed by ultrasound speed, single photon absorptiometry and direct measurement of porosity and specific gravity. It was concluded that measurement of the dorsal cortical proportions of the third metacarpal bone may provide a way of estimating the level of strains caused by fast exercise in this part of the bone, and hence the modelling response to be expected.

Bone mineral content and density in asymptomatic children with coeliac disease on a gluten-free diet.

Osteoporosis is a complication of coeliac disease. A gluten-free diet improves but does not normalize bone mineral density in adult patients. Only limited data are available regarding the influence of the disease and diet on bone mineralization in children. The aim of this study was to evaluate the radial bone mineral content and density in children and adolescents who are asymptomatic on a gluten-free diet. The bone mineral content (BMC) and density (BMD) values of the non-dominant radius midshaft in 91 children (53 girls, 38 boys, mean age 11.7 years, mean duration of disease 8.7 years) were determined by single-photon absorptiometry. At the diagnosis and at least three years after commencement of a gluten-free diet, serum calcium, phosphorus, albumin concentrations and alkaline phosphatase activities were measured in all patients, and intact parathormone concentrations in 16 patients. The mean BMC Z-score value in the female adolescent group only was significantly lower than normal (mean Z-score -1.04, P < 0.01). In contrast, the mean BMD Z-score was significantly higher compared to a healthy population both in girls (mean Z-score +1.36, P < 0.001) and in boys (mean Z-score +0.53, P < 0.02), as well as in the total patient group (mean Z-score +1.01, P < 0.001). The radial diameter was significantly smaller than normal in both pre-pubertal and adolescent groups. Serum laboratory parameters of asymptomatic patients were in the normal range. The parathormone mean value was significantly lower after at least three years of gluten-free diet than at diagnosis (mean +/- SD 3.77 +/- 1.07 versus 7.89 +/- 2.54 pmol/l, P < 0.01), but significantly higher compared to controls (2.89 +/- 0.90 pmol/l, P < 0.05). These data indicate that treated, asymptomatic coeliac children and adolescents have normal or even higher radius mineral density values than controls, but the bone size remains reduced. Although there is no direct evidence of calcium malabsorption in this cohort of coeliac patients, the slightly higher parathormone levels, together with some other factors, particularly delayed puberty, may result in reduced bone size.

Bone loss in relation to menopause: a prospective study during 16 years

This prospective study evaluated bone loss in the peri- and postmenopausal period in 156 women followed from age 48 to 64 years. All women were premenopausal at the start of the study. Areal bone mineral density (g/cm 2) was measured by single-photon absorptiometry (SPA) of the forearm at the 1 cm level (BMD 1 cm) and the 6 cm level (BMD 6 cm) every second year. Onset of menopause (MP) was determined according to the criteria of the World Health Organization (12 months of amenorrhea and elevated follicle-stimulating hormone). At the end of the study, 125 of 156 women (80%) remained. Bone mineral density (BMD) at age 48 years correlated with BMD at age 64 years within the respective region ( r = 0.4–0.5, p < 0.001, respectively). There was no BMD loss in the premenopausal period. BMD loss was accelerated at menopause (MP) independent of chronological age. BMD loss was greater during the first 5 years following MP than during the following 6 years (BMD 1 cm 2.4% per year [1.0%–3.9%] vs. 0.4% per year [−0.3%–1.0%], p < 0.01). The quartile of women with late MP (>53.7 years) had greater bone loss during the first 5 years after MP than the quartile of women with early MP (<50.3 years) ( p < 0.001). At age 64 years, BMD was no different when comparing the quartile of women with late MP vs. the quartile of women with early MP. Furthermore, there was no correlation between age at menopause and BMD at the age of 64. In summary, among women still menstruating at age 48 years, there was no measurable BMD loss in the premenopausal period. Independent of chronological age, BMD loss accelerated during MP. Rates of loss were highest in the early postmenopausal period. Independent of age at MP, premenopausal women with low age-specific BMD at age 48 years had an increased risk of sustaining low BMD at age 64 years also.

Association of Hypogonadism and Estradiol Levels with Bone Mineral Density in Elderly Men from the Framingham Study

Both hypogonadism and low estrogen levels adversely affect bone health in young men. In elderly men, who are at greatest risk for osteoporotic fracture, the influence of hypogonadism on bone mineral density remains unclear, as does the relative effect of estrogen status compared to hypogonadism. To examine the relation of hypogonadism and estrogen status to bone mineral density in elderly men. Community-based, prospective cohort study. Framingham, Massachusetts. Male participants of the Framingham Study. Total testosterone, total estradiol, and luteinizing hormone were measured in participants at all four biennial examinations from 1981 to 1989. Values from at least three of four examinations were averaged. Hypogonadism was defined as a mean testosterone level less than 10.4 nmol/L (<3.0 ng/mL) or a mean luteinizing hormone level of 20 IU/L or greater. An alternate definition of hypogonadism based only on a mean testosterone level less than 10.4 nmol/L (<3.0 ng/mL) was also used. In 1988-1989, bone mineral density was measured at the proximal femur (femoral neck, Ward triangle, and trochanter) and lumbar spine by using dual-photon absorptiometry and at the radial shaft by using single-photon absorptiometry. The association of hypogonadism with bone mineral density was examined with adjustment for confounders, including estradiol levels. A similar model that adjusted for hypogonadism was used to examine the association of estradiol level (ranked as quartiles) with bone mineral density. Of 448 men with bone mineral density measurements, 405 had evaluable hormone levels (mean age, 75.7 years [range, 68 to 96 years]); 71 (17.5%) of the 405 men were hypogonadal. Bone mineral density at any site did not significantly differ in hypogonadal men compared with eugonadal men (for example, bone mineral density at the femoral neck was 0.89 g/cm(2) vs. 0.87 g/cm(2), respectively; P > 0.2), even when alternate definitions of hypogonadism were used. In contrast, compared with the lowest estradiol quartile, men with higher estradiol levels had greater mean bone mineral density at all sites (for example, bone mineral density at the femoral neck was 0.84 g/cm(2), 0.88 g/cm(2), 0.86 g/cm(2), and 0.91 g/cm(2) from the lowest to the highest estradiol quartile; P for trend = 0.002). The difference in mean bone mineral density between men in the lowest and those in the highest estradiol quartile levels was similar to the effect of 10 years of aging on bone mineral density. In elderly men, hypogonadism related to aging has little influence on bone mineral density, but serum estradiol levels have a strong and positive association with bone mineral density.

Clinical review 117: Hormonal determinants and disorders of peak bone mass in children.

P BONE MASS can be defined as the maximal bone mineral density that is accrued during growth and development plus subsequent consolidation that continues during early adulthood (1). The precise age at which peak bone mineral density is acquired is still unknown and may be site dependent. It is generally accepted that maximal bone density is present during the third to fourth decade, but this assumption is based upon data derived from studies using densitometry techniques that are less precise than newer methods. Normative data are derived primarily from crosssectional studies of adolescents and young adults, such as cohorts of the National Health and Nutrition Examination Survey (NHANES). Differences in absolute density depend on the various techniques used for assessing bone density [i.e. single photon absorptiometry, dual energy x-ray absorptiometry (DEXA), quantitative computed tomography (QCT)] and differences using the same method among different machines, emphasizing the importance of methodology, including the type of machine used when referencing normative databases. There are also ethnic differences in bone density, with blacks reported as having higher bone density than whites. There are gender differences in bone density during childhood and adolescence due to differences in the timing of growth and puberty, resulting in females reaching peak bone mass earlier than males, although bone density values at peak bone mass are similar between the sexes. An individual’s height, bone size, and skeletal age may all impact bone density values, particularly in growing children and adolescents. These variables should be considered when assessing the normality of an individual’s bone density, but unfortunately current reference data do not include information on these variables. More recent investigations have suggested that peak bone mass may be attained as early as late adolescence in the hip and spine (1). In healthy adolescents, bone mass increases throughout childhood, with maximal bone mass accrual occurring in early to midpuberty and slowing in late puberty (2–5). However, most published studies are cross-sectional and do not include individuals in sufficient numbers encompassing the entire age span of interest (i.e. teens to fourth decade) followed prospectively to definitively determine the age at which peak bone mass is attained. Longitudinal data from healthy girls demonstrate that the gain in bone mass is most pronounced between 11–14 yr of age and falls significantly after 16 yr of age and/or 2 yr after menarche, as shown in Fig. 1 (4, 5). These data suggest that there is a critical window in time to maximize bone density in early and midadolescence, and the majority of bone mass will accumulate by late adolescence. It has been shown in adult patients that each sd reduction in bone density is associated with a doubling of fracture risk. In children, as in adults, fracture rates have also been shown to be higher in individuals with a lower bone mineral content (6). Because an individual’s bone density is determined by peak bone density and the degree of later bone loss, an understanding of the factors responsible for maximizing peak bone mass is critical for preventing fractures in later life. In this review, the factors that influence the attainment of peak bone mass, particularly hormonal determinants and disorders, will be considered.

Determinants of tibial ultrasound velocity (TUV) in post-menopausal women: relationship to single photon absorptiometry (SPA) and fracture history

Determinants of tibial ultrasound velocity (TUV) in post-menopausal women: relationship to single photon absorptiometry (SPA) and fracture history

Changes in calciotropic hormones and biochemical markers of bone metabolism in patients with human immunodeficiency virus infection

Data on the bone metabolism of human immunodeficiency virus (HIV)-infected patients are still extremely rare. To investigate the influence of HIV infection on the calciotropic hormones and markers of bone metabolism, we therefore performed a cross-sectional study on 100 patients (65 males and 35 females) with proven HIV infection. The following criteria were used for exclusion from the study: age less than 20/more than 50 years, confinement to bed, wasting symptoms, treatment with agents containing ketoconazole, renal or hepatic insufficiency, clinical or echographic signs of liver cirrhosis, endocrine diseases, or treatment with medications known to influence bone metabolism. Bone mineral content (BMC) was determined by single-photon absorptiometry on the left forearm. Reduced BMC was found among the male and female HIV-infected patients. Additional long-term use of heroin resulted in a severe loss of mineralization in the respective females. The markers of bone metabolism were determined in urine and serum samples. Significantly lower osteocalcin concentrations were found, indicating a reduced bone formation rate whose severity showed a significant correlation with the progressive loss of CD4 helper cells and was independent of low vitamin D3 levels (1,25-dihydroxycholecalciferol) and alterations of protein metabolism. Increased urinary excretion of cross-links as an expression of enhanced bone resorption was likewise significantly correlated with the loss of CD4 helper cells and independent of the vitamin D concentration and protein metabolism. It is therefore concluded that the changes in bone metabolism are mainly due to mechanisms of the impaired immune defense of HIV-infected patients.

The Sp1 binding site polymorphism in the collagen type I alpha 1 (COLIA1) gene is not associated with bone mineral density in healthy children, adolescents, and young adults.

Up to 85% of the variance in bone mineral density (BMD) is genetically determined. A putative candidate gene involved in the regulation of bone mass is the COLIA1 gene encoding type I collagen, which is the major protein of bone. We examined possible allelic influences of a G to T COLIA1 gene polymorphism in a recognition site for the transcription factor Sp1 on: (i) gain of forearm BMD using single photon absorptiometry (SPA); and (ii), BMD of the forearm, spine, hip, and whole body with dual X-ray absorptiometry (DXA). At baseline, 269 healthy boys and girls aged 8.2-16.5 years were eligible for the study. Forearm BMD measurements obtained at baseline and after 3.8+/-0.1 years (+/-s.d.) were used to calculate the annual percentage change in BMD. Calcium intake and physical activity were determined by a detailed questionnaire at baseline and after 1 year. Essentially no significant differences in forearm BMD gain or in BMD assessed at the forearm, spine, and whole body were observed among the three COLIA1 genotypes. In conclusion, the data indicate that the polymorphism at the Sp1 site in the COLIA1 gene is not associated with BMD or gain of forearm BMD in healthy boys and girls.

Bone metabolism and mineral density following renal transplantation

AIMTo study bone turnover following renal transplantation using a panel of biochemical markers and to correlate the results with both areal and volumetric bone mineral density (BMD).PATIENTSA total of 31...

Ultrasonographic, axial, and peripheral measurements in female patients with benign hypermobility syndrome.

Twenty-five female Caucasians, aged 19-57 years, with the hypermobility syndrome had bone density measurements using established noninvasive techniques such as dual X-ray absorptiometry (DXA), single photon absorptiometry (SPA), heel ultrasound (US), and peripheral computed tomography (pQCT) acquisitions of the radius. As a group, comparisons of the different bone indices with the corresponding age-matched reference population resulted in normal z-scores for the arial densities, however, values for the volumetric total and cortical bone at the radius measured by pQCT were significantly lower than expected (P < 0.0001). Spinal and femoral bone density results were significant after correction for body mass index (BMI). This cross-sectional study shows that the benign hypermobility syndrome patients have lowered t-scores for data reflecting bone structure and bone strength as measured with US and the tomographic technique.

Prediction of bone mass change after parathyroidectomy in patients with primary hyperparathyroidism.

A major challenge in the management of primary hyperparathyroidism (pHPT) is the decision regarding which patients should undergo parathyroidectomy (PTX), although the Consensus Development Conference of the NIH has proposed guidelines for the indication of surgery. In the present study, changes in bone mineral density (BMD) after PTX were compared between pHPT patients who did and did not meet the NIH criteria, and we further tried to predict the BMD change after PTX from preoperative parameters. The subjects were 44 pHPT patients (30 women and 14 men) who had had successful PTX. Lumbar and radial BMD were measured before and 1 yr after PTX by dual energy x-ray absorptiometry and single photon absorptiometry, respectively. Average annual percent increases in lumbar and radial BMD after PTX were 12.2 +/- 1.4% and 11.6 +/- 1.6% (mean +/- SEM), respectively, and those net increases were 0.0803 +/- 0.0008 and 0.0484 +/- 0.0006 g/cm2, respectively. There were no significant differences in percent or net changes in either radial or lumbar BMD after PTX between the groups divided according to each of the NIH criteria, such as age (> or =50 and <50 yr), serum calcium level (> or =12 and <12 mg/dL) or the existence of urinary stones (presence and absence). On the other hand, when the subjects were divided on the basis of radial BMD (above and below a z-score of -2), the annual percent and net increases in lumbar BMD and percent increase in radial BMD after PTX were significantly higher in the group with the lower z-score. Next, patients were divided into two groups with and without the indication of PTX based on NIH guidelines. Twenty-nine patients had the surgical indication by meeting one or more of these criteria and 15 patients had no indication without meeting any of the criteria. There were no significant differences between the two groups in annual percent or net changes in radial or lumbar BMD after PTX. A stepwise multiple regression analysis revealed that serum alkaline phosphatase level and the severity of cortical bone mass reduction were the best predictors of both percentage and net changes in lumbar BMD, with high determination coefficients (r2 > 0.7). In conclusion, a considerable increase in BMD could be obtained after PTX even in patients without surgical indication from the NIH. Alkaline phosphatase and the severity of cortical bone mass reduction are clinically useful for predicting the changes in lumbar BMD after PTX. The present findings provide a useful clue for the indication of surgery in pHPT.

Effects of growth during infancy and childhood on bone mineralization and turnover in preterm children aged 8‐12 years

To investigate the effect of growth on later bone mass and turnover, bone mineral content (BMC) and density (BMD: dual X‐ray absorptiometry (QDR 1000W) and single photon absorptiometry (Lunar SP2)) and bone turnover (plasma osteocalcin, urine deoxypyridinoline) were measured at 8‐12 y in 244 preterm children who had weight and height measured at 18 mo and 7.5‐8 y corrected age. Weight and length at birth, 18 mo, 7.5‐8 y and current follow‐up showed increasingly strong, positive correlations with bone area, BMC and BMD. After adjusting for current size, there were significant negative associations between earlier size measurements and later whole body and lumbar spine bone mass which were stronger for length than for weight, and a negative relationship between birthweight for gestation and later radial bone mass; but no relationship with bone turnover. Current calcium intake and activity level had no independent effect on bone mass. Bone mass at 8‐12 y is related to current bone and body size, which tracks throughout childhood. However, amongst children of the same current size, those who have shown the greatest increase in size, particularly in height, have the highest bone mass. These findings raise the hypothesis that improving linear growth in vulnerable children may be important in maximizing bone mass.

Double-blind, randomized trial of a synthetic triacylglycerol in formula-fed term infants: effects on stool biochemistry, stool characteristics, and bone mineralization

The low sn-2 palmitate content of infant formulas results in formation of fatty acid calcium soaps in the stools and reduced calcium absorption. Our objective was to test the hypotheses that increasing the proportion of sn-2 palmitate in formula for term infants would result in greater skeletal mineral deposition and reduced stool hardness. Healthy term neonates were randomly assigned to receive standard formula (n = 103) or formula containing 50% sn-2 palmitate (high-sn-2 formula; n = 100) for 12 wk. One hundred twenty breast-fed infants were also studied. The main outcome measures were 1) radial (single-photon absorptiometry) and whole-body (dual-energy X-ray absorptiometry) bone mineral content (WBBMC) at 12 wk and 2) stool frequency, volume, and consistency at 6 and 12 wk. Secondary outcome measures included stool fatty acid content. Infants receiving high-sn-2 formula had higher WBBMC (128.1 +/- 9.7 compared with 122.7 +/- 10.1 g, adjusted for size and sex), softer stools at 6 and 12 wk, and a lower proportion of stool soap fatty acids than did infants receiving the control formula. Breast-fed infants had adjusted WBBMC values (128.3 +/- 9.1 g) similar to those of infants fed high-sn-2 formula and significantly higher than those of infants fed the control formula. Changing the stereoisomeric structure of palmitate in infant formula resulted in higher WBBMC, reduced stool soap fatty acids, and softer stools more like those of breast-fed infants. The greater bone mass measured could be important if it persists beyond the trial period; this merits further investigation.

Changes in levels of catalase and glutathione in erythrocytes of patients with stable asthma, treated with beclomethasone dipropionate

Cross-sectional studies have suggested that asthmatic patients receiving high dose inhaled corticosteroids and intermittent courses of oral corticosteroids have reduced bone mass. This prospective 2-yr study was undertaken to evaluate changes in bone density of patients receiving high doses of inhaled corticosteroids. Patients (n = 33) (males aged 18-50 yrs, females aged 18-40 yrs) on inhaled corticosteroids 1,000-2,000 microg x day(-1), were randomized in a double-blind fashion to either fluticasone propionate (FP) 1,000 microg x day(-1) or beclomethasone dipropionate (BDP) 2,000 microg x day(-1). In parallel, three open control groups of the same age range were studied: asthmatics (n = 8) receiving low dose inhaled corticosteroids (&lt; or =400 microg x day(-1)) (group A); chronic, severe asthmatics (n = 8) receiving oral corticosteroids (&gt; or =10 mg x day(-1) (group B); and healthy untreated volunteers (n = 7) (group C). Bone densitometry scans (quantitative computed tomography (QCT) of spine; dual X-ray absorptiometry of spine, femoral neck, and single photon absorptiometry of forearm) were performed at baseline and after 6, 12 and 24 months of treatment. Biochemical bone marker measurements (serum osteocalcin, bone alkaline phosphatase, pro-collagen type 1 carboxy terminal propeptide, deoxypyridinoline and C-telopeptide of type 1 collagen) were collected every 3 months. Fifteen FP (mean age 36 yrs, six male) and 9 BDP patients (mean age 33 yrs, five male); completed the study. At 0 months, mean bone mineral density (BMD) was lower in patients receiving inhaled corticosteroids (both low dose and high dose) than in normal volunteers. In the FP-treated group, mean vertebral trabecular BMD quantitative computed tomography remained stable with no evidence of decline, whereas there was some decline in the BDP-treated group. The treatment difference between FP and BDP was statistically significant in favour of FP for quantitative computed tomography measurements after 12 months (p = 0.006) and 24 months (p = 0.004). This study suggests that over 24 months, changes in bone density are minimal in patients on high-dose inhaled corticosteroids.

A randomized, double‐blind study comparing the effects of beclomethasone and fluticasone on bone density over two years

Cross-sectional studies have suggested that asthmatic patients receiving high dose inhaled corticosteroids and intermittent courses of oral corticosteroids have reduced bone mass. This prospective 2-yr study was undertaken to evaluate changes in bone density of patients receiving high doses of inhaled corticosteroids. Patients (n = 33) (males aged 18-50 yrs, females aged 18-40 yrs) on inhaled corticosteroids 1,000-2,000 microg x day(-1), were randomized in a double-blind fashion to either fluticasone propionate (FP) 1,000 microg x day(-1) or beclomethasone dipropionate (BDP) 2,000 microg x day(-1). In parallel, three open control groups of the same age range were studied: asthmatics (n = 8) receiving low dose inhaled corticosteroids (< or =400 microg x day(-1)) (group A); chronic, severe asthmatics (n = 8) receiving oral corticosteroids (> or =10 mg x day(-1) (group B); and healthy untreated volunteers (n = 7) (group C). Bone densitometry scans (quantitative computed tomography (QCT) of spine; dual X-ray absorptiometry of spine, femoral neck, and single photon absorptiometry of forearm) were performed at baseline and after 6, 12 and 24 months of treatment. Biochemical bone marker measurements (serum osteocalcin, bone alkaline phosphatase, pro-collagen type 1 carboxy terminal propeptide, deoxypyridinoline and C-telopeptide of type 1 collagen) were collected every 3 months. Fifteen FP (mean age 36 yrs, six male) and 9 BDP patients (mean age 33 yrs, five male); completed the study. At 0 months, mean bone mineral density (BMD) was lower in patients receiving inhaled corticosteroids (both low dose and high dose) than in normal volunteers. In the FP-treated group, mean vertebral trabecular BMD quantitative computed tomography remained stable with no evidence of decline, whereas there was some decline in the BDP-treated group. The treatment difference between FP and BDP was statistically significant in favour of FP for quantitative computed tomography measurements after 12 months (p = 0.006) and 24 months (p = 0.004). This study suggests that over 24 months, changes in bone density are minimal in patients on high-dose inhaled corticosteroids.