Leg Bone Mineral Density Research Articles

Sport and Training Influence Bone and Body Composition in Women Collegiate Athletes

This is a novel descriptive study to characterize off-season, preseason, and postseason bone and body composition measures in women collegiate athletes. From 2006 through 2008, 67 women collegiate athletes from 5 sports, softball (n = 17), basketball (n = 10), volleyball (n = 7), swimming (n = 16), and track jumpers and sprinters (n = 17) were scanned using dual energy X-ray absorptiometry (DXA) at 3 seasonal periods: (a) off-season = before preseason training, (b) preseason = after preseason training, and (c) postseason = after competitive season. Dual energy X-ray absorptiometry scans were analyzed for total body mass, lean mass (LM), fat mass (FM), percent body fat (%BF), bone mineral content, bone mineral density (BMD), arm BMD, leg BMD, pelvis BMD, and spine BMD. Data were analyzed between sports using analysis of variance (ANOVA) with Tukey post hoc follow-ups, and within each sport using repeated-measures ANOVA and LSD; alpha < 0.05. Significant off-season to preseason or postseason changes in %BF, LM, and BMD within each sport were as follows, respectively: softball, -7, +4, +1%; basketball, -11, +4, +1%; volleyball, unchanged, unchanged, +2%; swimming, unchanged, +2.5%, unchanged; track jumpers and sprinters, -7, +3.5, +1%. Comparisons among athletes in each sport showed bone measurements of swimmers averaged 4-19% lower than that of athletes in any other sport, whereas for track jumpers and sprinters, %BF and FM averaged 36 and 43% lower compared with other sports at all seasonal periods. Values for athletes playing basketball and volleyball were most similar, whereas softball athletes' values fell between all other athletes. These data serve as sport-specific reference values for comparisons at in-season and off-season training periods among women collegiate athletes in various sports.

Associations of fat mass and fat distribution with bone mineral density in pre- and postmenopausal Chinese women

Fat mass (FM) is closely related to bone mineral density (BMD). However, the associations of FM and fat distribution with BMD in pre- and postmenopausal women are still poorly understood. The present study showed android fat mass accumulation after menopause had a negative association with BMD. FM is closely related to BMD. However, it is unknown whether FM and central fat distribution have different associations with BMD in pre- and postmenopausal women. The study aims to investigate the associations of FM and fat distribution with BMD in pre- and postmenopausal Chinese women. Two hundred sixty premenopausal and 267 postmenopausal women aged 18 to 79years were analyzed. Lean mass (LM), FM, percent body fat (%BF), android FM, gynoid FM, and total and regional BMD were measured using dual-energy X-ray absorptiometry. Fat distribution was assessed by android to gynoid FM ratio (AOI). Multiple regression analysis was performed to examine the associations of BMD with FM, LM, and AOI. FM, %BF, android FM, and AOI were significantly higher, whereas total and regional BMD were significantly lower in postmenopausal women (all р < 0.01). In premenopausal women, FM was positively associated with total and regional BMD (all р < 0.05). AOI had no significant association with BMD. In postmenopausal women, FM was significantly associated with total and regional BMD even additionally adjusting for LM (all р < 0.01). AOI had significantly negative association with total, head, arm, and leg BMD (all р < 0.05). The results remained unchanged when replacing FM with %BF. There were different associations of FM and fat distribution with BMD in pre- and postmenopausal Chinese women. Increased central body fat had a negative association with BMD. Our findings may have significant implications in the prevention of menopause-related osteoporosis through reducing centralized fat deposition.

Effect of body fat stores on total and regional bone mineral density in perimenopausal Chinese women

Accumulation of body fat is known to be beneficial to bone mass through increased body weight. However, not all the skeleton is loaded by body weight. Therefore, we assume that fat stores would exert different effects on bone mass at different skeletal sites. In this study, 84 perimenopausal Chinese women were recruited. Using dual-energy X-ray absorptiometry, total body fat mass (TBFM), total body lean mass (TBLM), percent body fat (PBF), and total body and regional bone mineral density (BMD) were measured. Correlation analysis indicated that PBF correlated negatively with BMD at ribs and both arms (all P < 0.05). After adjusting for TBLM, PBF had a significantly negative correlation with BMD at head, ribs, both arms, and whole body (all P < 0.05). With adjustment for body weight and height, a significantly negative correlation between PBF and BMD was present, not only at ribs and arms but also at legs and whole body (all P < 0.05, except right leg, at P = 0.094). There was a significantly positive correlation between body weight and leg BMD (all P < 0.001). Body weight was positively correlated with TBFM (r (2) = 0.783, P < 0.001) and TBLM (r (2) = 0.770, P < 0.001). Based on the results, we conclude that increased body fat stores would exert a detrimental effect on BMD, but this effect is more prominent on non-weight-bearing bone. On weight-bearing bone, the detrimental effect of increased body fat could be offset or outweighed by the beneficial effect of increased body weight.

Age, gender, and race/ethnic differences in total body and subregional bone density.

Total body bone density of adults from National Health and Nutrition Examination Survey (NHANES) 1999-2004 differed as expected for some groups (men>women and blacks>whites) but not others (whites>Mexican Americans). Cross-sectional age patterns in bone mineral density (BMD) of older adults differed at skeletal sites that varied by degree of weight-bearing. Total body dual-energy X-ray absorptiometry (DXA) data offer the opportunity to compare bone density of demographic groups across the entire skeleton. The present study uses total body DXA data (Hologic QDR 4500A, Hologic, Bedford MA, USA) from the NHANES 1999-2004 to examine BMD of the total body and selected skeletal subregions in a wide age range of adult men and women from three race/ethnic groups. Total body, lumbar spine, pelvis, right leg, and left arm BMD and lean mass from 13,091 adults aged 20 years and older were used. The subregions were chosen to represent sites with different degrees of weight-bearing. Mean BMD varied in expected ways for some demographic characteristics (men>women and non-Hispanic blacks>non-Hispanic whites) but not others (non-Hispanic whites>Mexican Americans). Differences in age patterns in BMD also emerged for some characteristics (sex) but not others (race/ethnicity). Differences in cross-sectional age patterns in BMD and lean mass by degree of weight-bearing in older adults were observed for the pelvis, leg, and arm. This information may be useful for generating hypotheses about age, race, and sex differences in fracture risk in the population.

Female boxers have high bone mineral density despite low body fat mass, high energy expenditure, and a high incidence of oligomenorrhea

Low body fat mass and menstrual irregularities have been associated with low bone mineral density (BMD). The aim of this study was to compare the relation between BMD, lean body mass, fat mass, physical activity energy expenditure (PAEE), and menstrual status in female boxers and in physically active females with low (C1) or average (C2) fat mass. Boxers (n = 11) and controls (C1, n = 16; C2, n = 17), aged 18-38 years, were assessed for BMD and body composition with dual-energy X-ray absorptiometry. Menstrual status and PAEE were determined from questionnaires. There was no difference in anthropometric measurements between boxers and C1 subjects, except that boxers had higher arm lean mass. However, both boxers and C1 subjects had a lower percentage of fat (p < 0.001) than C2 subjects (boxers, 14.6% +/- 2.0; C1, 15.5% +/- 4.2; C2, 25.8% +/- 3.4%), and boxers had a higher (p = 0.002) lean body mass index (lean body mass/height2, where lean body mass is measured in kilograms and height is measured in metres) than C2 subjects. The PAEE of boxers was higher (p < 0.007) than that of controls (boxers, 5748 +/- 2284 ; C1, 2966 +/- 2258 ; C2, 2714 +/- 1722 kcal.week-1). Oligomenorrhea was more common in boxers than in C1 and C2 subjects (boxers, 54.6%; C1, 18.8%; C2, 35.3%). Arm, leg, and spine BMD were higher (p < 0.008) in boxers than in C1 subjects, and arm BMD was higher in boxers than in C2 subjects. BMD Z scores were also higher (p < 0.05) in boxers (boxers, 1.1+/- 0.8, C1, 0.1 +/- 0.7; C2: 0.3 +/- 1.1). High BMD in boxers, despite low fat mass, high PAEE, and an increased incidence of oligomenorrhea suggest that boxing has a positive effect on BMD.

Effect of weight-bearing activities on bone mineral density in spinal cord injured patients during the period of the first two years

Prospective study on patients with spinal cord injuries. To evaluate the loss of bone mineral density (BMD) in various body regions of patients with spinal cord injury (SCI) and its dependence on weight bearing activities during 2 years post injury. BMD of the whole body was measured in patients with SCI. Baseline measurement was performed in 6-16 weeks after SCI, the second and the third-respectively 12 and 24 months after injury. Fifty-four subjects were selected and divided into two groups: standing and non-standing. From these groups 27 pairs were made according to gender, age and height. There was found to be a well-marked decrease in BMD values for lower extremities, but there was no significant difference between paraplegic and tetraplegic patients 1 and 2 year after injury. Leg BMD reduced by 19.62% (95% CI, 17-22%) in the standing group and by 24% (95% CI, 21-27%) in non-standing group during the first year. Two years after SCI patients in standing group had significantly higher leg BMD-1.018 g/cm(2) (95% CI, 0.971-1.055 g/cm(2)) than in the non-standing group-0.91 g/cm(2) (95% CI, 0.872-0.958 g/cm(2)) (P<or=0.0001). SCI patients who performed daily standing >or=1 h and not less than 5 days per week, had significantly higher BMD in the lower extremities after 2 years in comparison to those patients who did not perform standing.

Effect of sports activity on bone mineral density in wheelchair athletes

The present study carried out a measurement of body composition and a nutrition survey, targeting 28 male wheelchair athletes and comparing them with 25 male physically able healthy athletes as the controls. The DXA method was used to measure bone mineral density (BMD), percentage of body fat (% body fat), and lean body mass (LBM). Possible factors affecting the BMD of the wheelchair athletes with spinal injuries were analyzed including age, body part, type of sport, area of injury, length of injury, and the length of time it took before restarting sports activity after injury. BMD in the arms, body trunk, legs, and entire body was measured. There were no significant differences in the BMD of the wheelchair athletes by age group (from 20 to 29, from 30 to 39, and 40 years and older), by sports (basketball, track and field, and tennis), and by area of injury (high and low paraplegia). BMD in the legs (r = -0.549, P < 0.01), body trunk (r = -0.414, P < 0.05), and entire body (r = -0.452, P < 0.05) of the wheelchair athletes was negatively correlated with the period since injury; however, no such a relationship was observed in the arms. In addition, the multiple regression analysis for BMD of each body region showed that the earlier the wheelchair athletes restarted sports after injury, the higher values the BMD of legs (r = -0.467, P < 0.05), body trunk (r = -0.469, P < 0.05), and entire body (r = -0.488, P < 0.05), independent of age and sports. The leg BMD of the wheelchair athletes was lower than that of the physically able athletes, with a BMD 76.5% of the controls. The present study suggests that restarting sports activity in a timely manner after treatment and rehabilitation for the injury is useful in preventing loss of BMD in wheelchair athletes and ultimately improving their quality of life.

WISE-2005: Supine treadmill exercise within lower body negative pressure and flywheel resistive exercise as a countermeasure to bed rest-induced bone loss in women during 60-day simulated microgravity

Bone loss associated with disuse during bed rest (BR), an analog of space flight, can be attenuated by exercise. In previous studies, the efficacy of either aerobic or resistive exercise countermeasures has been examined separately. We hypothesized that a regimen of combined resistive and aerobic exercise during BR would prevent bone resorption and promote bone formation. After a 20-day ambulatory adaptation to controlled confinement and diet, 16 women participated in a 60-day, 6° head-down-tilt BR and were assigned randomly to one of the two groups. Control subjects (CON, n = 8) performed no countermeasure. Exercise subjects (EX, n = 8) participated in an exercise program during BR, alternating between supine treadmill exercise within lower body negative pressure (3–4 d wk − 1 ) and flywheel resistive exercise (2–3 d wk − 1 ). By the last week of BR, excretion of helical peptide (CON, 79% ± 44 increase; EX, 64% ± 50, mean ± SD) and N-terminal cross-linking telopeptide (CON, 51% ± 34; EX, 43% ± 56), markers of bone resorption, were greater than they were before BR in both groups ( P < 0.05). However, serum concentrations of the bone formation marker procollagen type I N propeptide were greater in EX than CON throughout and after bed rest ( P < 0.05), while concentrations of the bone formation marker bone alkaline phosphatase tended to be greater in EX than CON. Dual-energy X-ray absorptiometry results indicated that the exercise treatment significantly ( P < 0.05) attenuated loss of hip and leg bone mineral density in EX compared to CON. The combination of resistive and aerobic exercise did not prevent bone resorption but did promote bone formation, and helped mitigate the net bone loss associated with simulated microgravity.

Relationship of fat mass and serum estradiol with lower extremity bone in persons with chronic spinal cord injury

In the spinal cord injury (SCI) population, a relationship between adiposity and leg bone has not been reported, nor one between serum estradiol and leg bone mass. A cross-sectional, comparative study of 10 male pairs of monozygotic twins discordant for SCI was performed. Relationships were determined among bone mineral density (BMD), bone mineral content (BMC), lean mass, fat mass, and serum sex steroids. In the twins with SCI, significant relationships were evident between leg BMD or BMC with total body percent fat (r2= 0.49, P < 0.05; r2= 0.45, P = 0.05), leg fat mass (r2 = 0.76, P < 0.0005; r2= 0.69, P = 0.005), and serum estradiol (r2= 0.40, P = 0.05; r2= 0.37, P = 0.05). By stepwise regression analysis, in the twins with SCI, leg fat mass was found to be the single most significant predictor of leg BMD or BMC (F = 12.01, r2= 0.76, P = 0.008; F = 50.87, r2= 0.86, P < 0.0001). In the able-bodied twins, leg lean mass correlated with leg BMD and BMC (r2= 0.58, P = 0.01; r2= 0.87, P = 0.0001). By use of within-pair differences, significant correlations were found for leg lean mass loss with leg BMD loss (r2= 0.56, P = 0.01) or leg BMC loss (r2= 0.64, P = 0.0005). In conclusion, in twins with SCI, significant correlations were observed between fat mass and leg BMD or BMC as well as between serum estradiol values and leg BMD. The magnitude of the leg muscle mass loss was correlated with the magnitude of bone loss.

The Receptor Activator of Nuclear Factor-κB Ligand Inhibitor Osteoprotegerin Is a Bone-Protective Agent in a Rat Model of Chronic Renal Insufficiency and Hyperparathyroidism

Osteoprotegerin (OPG) acts by neutralizing the receptor activator of nuclear factor-kappaB ligand (RANKL), the primary mediator of osteoclast differentiation, function, and survival. We examined whether OPG could affect the bone loss associated with chronic kidney disease (CKD) in a rodent model of CKD and secondary hyperparathyroidism (SHPT). SHPT was induced in rats by 5/6 nephrectomy (5/6 Nx) and a 1.2% P/0.6% Ca(2+) diet. Starting 1 week after 5/6 Nx, rats were treated with vehicle (veh) or OPG-Fc (3 mg/kg, intravenously) every 2 weeks for 9 weeks. At baseline, 3, 6, and 9 weeks, blood was taken and bone mineral density (BMD) and bone mineral content (BMC) were assessed by dual-energy X-ray absorptiometry. Serum parathyroid hormone (sPTH) levels reached 912 pg/ml in 5/6 Nx rats vs. 97 pg/ml in shams at 9 weeks. OPG-Fc had no effect on sPTH or Ca(2+) levels throughout the 9-week study, indicating that SHPT was a renal effect independent of bone changes. At 3 weeks, 5/6 Nx-veh rats had osteopenia compared with sham-veh rats and 5/6 Nx-OPG-Fc rats had significantly higher percent changes in whole-body BMC, leg BMD, and lumbar BMD versus 5/6 Nx-veh rats. By 6-9 weeks, elevated sPTH was associated with reversal of bone loss and osteitis fibrosa in the proximal tibial metaphysis. OPG-Fc decreased this sPTH-driven high bone turnover, resulting in augmented thickness of proximal tibial trabeculae in 5/6 Nx rats. Thus, RANKL inhibition with OPG-Fc can block the deleterious effects of continuously elevated sPTH on bone, suggesting that RANKL may be an important therapeutic target for protecting bone in patients with CKD and SHPT.

Relationship between leg bone mineral values and muscle strength in women with different physical activity

This study examines whether knee extensor muscle isometric, isokinetic, and isoinertial strength values in women with different physical activity and body composition patterns are related to leg bone mineral density (BMD) and bone mineral content (BMC) values. A total of 129 women aged 17-40 participated in this study. They were divided into four groups: strength-trained (n = 33), endurance-trained (n = 32), normal weight sedentary (n = 41), and overweight sedentary (n = 23) women. In addition, the subjects were grouped as physically active (n = 65) or sedentary (n = 64) women. BMD and BMC for both legs (LBMD and LBMC, respectively) and for the dominant leg alone (DLBMC), body fat percentage and lean body mass (LBM), maximal knee extension isometric (ISOM) and isokinetic (ISOK) strength at the angular velocity of 60 deg.s(-1), and isoinertial leg explosive strengths (countermovement jump CMJ) were measured. In endurance-trained women, LBMD was dependent on body mass index (BMI) (33.7% of the variance, R2 x 100), and in the physically active group and the total group with LBM (14.6% and 15.6%, respectively). In the overweight group, LBMD was dependent on ISOK strength (21.7% of the variance, R2 x 100). In the sedentary and total groups, ISOM strength was more important (10.3% and 5.0%, respectively); in the strength-trained group, body weight influenced LBMC, accounting for 71.6% of the variance (R2 x 100). In the endurance-trained women, height influenced LMBC (37.9%, R2 x 100). In sedentary and overweight women, LBM accounted for 52.1% and 61.4% of the total variance in LBMC. In these groups, ISOM strength accounted for 15.3% and 25.9% of the variance in LBMC. In overweight women, ISOM and ISOK strength together influenced LBMC highly (64.8% of the variance, R2 x 100). In the sedentary group, the influence of LBM on LBMC was higher than in the active group (82.1% and 50.5% of the variance, respectively). In the total group, LBM influenced LBMC, accounting for 54.5% of the variance (R2 x 100). ISOM strength (22.7%) alone or in combination with ISOK strength (35.8%) and CMJ (41.7%) (R2 x 100) in LBMC in the sedentary group explained the variance. In the total group, ISOM strength alone (13.2%) or in combination with CMJ (17.1%) influenced LBMC (R2 x 100). Our results suggest that (1) muscle strength and anthropometrical parameters were associated with LBMD; (2) LBM and ISOM strength had a significant relationship with DLBMC and LBMC only in nonathletic women; and (3) strength measured with different regimens highly influenced LBMC compared with LBMD, especially in the sedentary groups.

Postmenopausal bone mineral density in relation to soy isoflavone-metabolizing phenotypes

Objectives Intestinal bacterial metabolize the soy isoflavone daidzein to O-desmethylangolensin ( O-DMA) or equol. Some individuals do not excrete O-DMA or equol after soy consumption, suggesting they do not harbor bacteria capable of producing these metabolites. The aim of this study was to evaluate bone mineral density (BMD) in relation to presence of these urinary metabolites. Methods BMD, determined by whole-body dual X-ray absorptiometry scan, was age-adjusted and evaluated in relation to O-DMA-producer and equol-producer phenotypes in 92 postmenopausal women, aged 50–75 years. Women consumed supplemental soy foods (daidzein source) for 3 days and collected a first-void urine sample on the fourth day in order to determine metabolic phenotypes. Results In O-DMA producers ( n = 76) compared to O-DMA non-producers ( n = 16), greater total, leg and head BMD ( p < 0.05) were observed. Total BMD among the O-DMA producers (geometric mean = 1.04 g/cm 2) was 6% greater than total BMD among the O-DMA non-producers (geometric mean = 0.98 g/cm 2). Total and site-specific BMD did not differ between equol producers ( n = 24) and non-producers ( n = 68) ( p > 0.05). In exploratory analyses, among regular soy consumers, spinal BMD was 20% lower among the equol producers than non-producers, whereas, among soy non-consumers, no such difference was observed ( p-interaction < 0.05). Among equol producers, circulating estrone and free estradiol concentrations were inversely or not associated with total BMD, whereas, among equol non-producers, these hormones were positively associated ( p-interaction < 0.05). Conclusions Our results provide evidence that intestinal bacterial composition may influence BMD in postmenopausal women. Further studies characterizing associations of intestinal bacterial profiles with BMD are warranted.

Body Composition And Bone Mineral Density Of Middle distance And Long-distance Elite Female Runners Do Not Differ

PURPOSE The purpose of this study was to compare the body composition and bone mineral density of elite female middle-distance runners (MDR) and long distance runners (LDR) to determine if either group is at higher risk for musculoskeletal injury. METHODS Athletes studied were 23 LDR and 24 MDR elite level runners (NCAA Div. I or USATF National Championships participants). LDR athletes competed at distances from 5,000 m through the marathon, whereas MDR athletes competed at 800 m through 3,000 m. Over a several-year period, these runners were assessed in the Laboratory for Elite Athlete Performance at Georgia State University using a protocol approved by the University's IRB. Bone mineral density (BMD) was assessed via a full body scan using a LUNAR DPXL densitometer (DEXA), with total body, leg and spine BMDs derived from this scan. Body composition was assessed using both DEXA fat percentage and the fat percentage calculated from the total of 7 skinfold measurements applied to the Jackson, Pollock, and Ward formula (MSSE 12:175 182, 1980). From these data, ratios of total and lean body mass to bone density were calculated in the two groups of runners to further assess stress-fracture risk RESULTS Mean values ± SEE for the LDR and MDR groups were similar for height (165.7 ± 1.15 vs. 167.5 ± 0.66 cm), weight (53.3 ± 0.88 vs. 53.3 ± 0.78 kg), skinfold fat percentage (12.9 ± 0.31 vs. 12.5 ± 0.37), and DEXA fat percentage (13.2 ± 0.57 vs. 12.3 ± 0.59), but the LDR athletes were older (27.0 ± 0.87 vs. 24.6 ± 0.80 yr; P = 0.002). Also similar were mean values ± SEE (gm/cm2) for the LDR and MDR groups regarding total BMD (1.168 ± 0.014 vs 1.181 ± 0.009), spine BMD (1.109 ± 0.020 vs. 1.121 ± 0.018) and leg bone BMD (1.293 ± 0.019 vs. 1.318 ± 0.012). Stress fracture risk appears to be similar, as seen by nonsignificant differences between the LDR and MDR groups in the mean values ± SEE of total, leg, and spine BMD, and the ratios between lean body mass and total bone density (39.8 ± 0.68 vs. 39.5 ± 0.49), total body mass and total bone density 45.7 ± 0.82 vs. 45.1 ± 0.53), lean body mass and leg bone density (36.0 ± 0.64 vs. 35.4 ± 0.43), and total body mass and leg bone density (41.3 ± 0.77 vs. 40.5 ± 0.49). CONCLUSIONS Although the two groups of elite female distance runners train differently (more mileage, less intensity for LDR; the reverse for MDR), the net skeletal and body composition response to training is similar.

The Effects Of Exercise Training Mode On Biochemical Indices Of Bone Turnover And Bone Density In Untrained, Young Women

PURPOSE The study was designed to examine the efficacy of either step aerobics or resistance exercise to induce positive changes in bone density in previously untrained, young women. METHODS Sixty-nine women between 20–35 years of age completed the first six months of a year long study investigating the effects of exercise mode or non-intervention (control) on changes in bone mineral density (BMD) and biochemical markers of bone turn-over. Those who completed the six month assessments were distributed as follows: step aerobics (SA) n=27; resistance training (RT) n=22; control (CON) n=20. Assessments for bone density (DEXA and Pixi scan) and biochemical markers of bone turnover (calcitonin, osteocalcin, NTx, PTH) were made at baseline and following six months of group assignment. Supervised exercise session were held three days/week for RT and SA. RESULTS There were no significant group differences at baseline for BMD. Unadjusted changes in BMD were significantly greater for heel BMD in SA than RT and CON (p<0.01). Lumbar 3 BMD and left leg BMD increased in SA more than in RT (p<0.05 for both). However, hip BMD was reduced in SA compared to RT (p<0.05). ANOVA revealed a significant time effect (p=0.042) but no interaction or group effect for calcitonin and a significant group effect for osteocalcin (p=0.50) with SA being significantly higher than RT. CONCLUSIONS Based on the results of this study, six months of SA or RT appear to produce positive but different effects on bone remodeling and BMD with minor changes in biochemical markers of bone turn-over. Supported by NIH grant #5 806 GM053933-06 and NASA grant #SAA2-401535

Effect of a vitamin D analog on leg bone mineral density in patients with chronic spinal cord injury

A randomized, placebo-controlled trial was performed to determine the effect of a vitamin D analog (1-alpha-hydroxyvitamin D(2) [1-alpha D(2)]) on the bone mineral density (BMD) in patients with chronic spinal cord injury (SCI). Forty subjects with chronic complete motor SCI were enrolled. The mean plus or minus standard deviation age and duration of injury were 42 plus or minus 12 yr and 11 plus or minus 10 yr, respectively. Either 4 micrograms 1-alpha D(2) (n = 19) or placebo (n = 21) was administered daily for 24 mo. Metabolic markers of bone resorption and formation were obtained. Regional lower-limb dual-energy x-ray absorptiometry was performed at baseline and at 6, 12, 18, and 24 mo. Leg BMD and percent change from baseline significantly increased at 6 (percent change only), 12, 18, and 24 mo in the treatment group, but not in the placebo group. Urinary N-telopeptide, a marker of bone resorption, was significantly reduced during treatment with 1-alpha D(2), but markers of bone formation were not changed.

Effect of pamidronate administration on bone in patients with acute spinal cord injury

Eleven subjects participated in a prospective placebo-controlled trial to address the efficacy of pamidronate in reducing bone loss in persons with acute spinal cord injury (SCI). We administered pamidronate (treatment) or normal saline (placebo) intravenously at baseline (22 to 65 days after injury) and sequentially over 12 months, with follow-up at 18 and 24 months. Regional bone mineral density (BMD) was lost over time, regardless of group. In the treatment group compared with the placebo group, we noted a mild early reduction in loss of total leg BMD. Significant bone loss from baseline occurred earlier in the placebo group at the regional sites than in the treatment group. However, by the end of the treatment and follow-up phases, both groups demonstrated a similar percent bone loss from baseline. Despite an early reduction in bone loss, pamidronate failed to prevent major, long-term bone loss in persons with acute neurologically complete SCI.

Bone assessment of female long-distance runners.

The objective of the present study was to investigate the effects of long-distance training on the bones in different growth stages by evaluating the bones of female high school athletes and female adult athletes who engage in long-distance training. Thirteen female high school athletes (aged 15-17 years) and 7 female adult athletes (aged 21-25 years) were enrolled in the present study. Bone mineral density (BMD) and bone mineral content (BMC) were measured using dual X-ray absorptiometry (DXA). Cortical bone status was also evaluated by measuring the tibial speed of sound (t-SOS). The bone metabolic status was evaluated by osteocalcin (OC) and tartrate-resistant acid phosphatase (TRAP). OC ( P < 0.01) and lumbar BMD ( P < 0.05) were significantly higher in high school athletes who were in the modeling period than in the adult athletes. Leg BMD ( P < 0.01) and t-SOS ( P < 0.05) were significantly higher in adult athletes who were in the remodeling period than in high school athletes. When lumbar BMD and leg BMD were compared according to menstrual conditions, the high school athletes with regular menstruation showed a significantly higher level of bone density than those having irregular or absent menstruation. These results indicate that the effect of long-distance training on bone metabolism is influenced strongly by sex hormones during late puberty. We concluded that the effect of long-distance training on bone metabolism in the female high school athletes (i.e., during puberty) was different from that in the adult athletes.

A Pilot Intervention to Increase Calcium Intake in Female Collegiate Athletes

Calcium intake in adolescent and young adult female athletes often is inadequate to optimize peak bone mass, an important determinant of osteoporosis risk. The purpose of this study was to determine if calcium supplementation in eumenorrheic female collegiate athletes increases intake to recommended levels and promotes increases in bone mineral density (BMD). Forty-eight eumenorrheic female athletes from several college teams (15 soccer, 7 cross-country, 8 indoor track, and 18 basketball) were randomized at the beginning of a competitive season to receive either an oral calcium supplement (1000 mg calcium citrate/400 I.U. Vitamin D) or placebo daily throughout the training season (16 weeks). Self-reported daily pill intake was obtained every 2 weeks to assess adherence. Calcium intake was evaluated using the Rapid Assessment Method, and total body and leg BMD was measured at pre-, mid-, and postseason using dual energy x-ray absorptiometry (DEXA; Hologic QDR-2000). Pre-season calcium intake was lower than national recommendations for this age group (12), averaging 842 mg/d (SD = 719) and was lower in the placebo group compared to the supplemented group (649 +/- 268 vs. 1071 +/- 986 mg/d, respectively; p = .064). Adherence to supplementation was good, averaging 70% across the training season. Supplementation boosted total calcium intake to a mean of 1397 +/- 411 mg/d, which is consistent with recommended levels for this group (37). Supplementation did not influence BMD change during this 16-week intervention. Across teams, a small increase of 0.8% was observed in leg BMD. Change in total body BMD was modified by team, with a significant increase of 1.5% observed in basketball players. These results indicate that providing calcium supplements of 1000 mg/d is adequate to boost total intake to recommended levels during athletic training. Longer intervention trials are required to determine whether calcium supplementation has a positive effect on BMD.

Hidden Depletion of Fat-Free Mass and Bone Mineral Density in Adults With Cystic Fibrosis

Weight loss is associated with reduced survival in patients with cystic fibrosis (CF). We hypothesized that some adult patients with a normal body mass index (BMI) have evidence of hidden fat-free mass (FFM) and bone mineral density (BMD) depletion that is linked to more severe disease. Fat mass (FM), FFM, and BMD were determined by dual-energy x-ray absorptiometry (DXA) and by bioelectric impedance in 56 adults in clinically stable condition and 20 age-matched healthy subjects. FM index and FFM index (FFMI) [kilograms per meter squared] of the right arm, leg, and trunk (ratio to height squared) were calculated. Lung function, including the maximum inspiratory pressure (MIP) and sustained MIP (SMIP), physical activity, serum C-reactive protein (CRP) and the number of exacerbations in the previous year were recorded. Patients had a lower total FFM than healthy subjects (p < 0.01), while FM was similar. Of the 56 patients, 30 patients had a normal BMI, of which 12 patients had a low FFM (hidden loss) by DXA. The right arm, leg, and trunk FFMI and BMD at hip sites were less in these patients than in those with a normal BMI and normal FFM (all p < 0.01). This group had a lower FEV(1), SMIP, more frequent exacerbations, and greater circulating CRP (all p < 0.05). In adults with CF, apparent or hidden loss of FFM, rather than weight loss, was related to overall disease severity. Hidden depletion of FFM was associated with increased loss of BMD and systemic inflammatory activity.

Age-related change in the strength of correlation of lumbar spine bone mineral density with other regions

Objectives: To investigate whether the strength of correlation of lumbar spine bone mineral density (BMD) with other regions differs with age. Methods: Subjects were 336 premenopausal women aged 20–49 years and 218 postmenopausal women aged 50–69 years with right-side dominance. Age, height, weight, and years since menopause (YSM) were recorded. Subjects were classified into five subgroups at 10-year increments. BMD of the arms, lumbar spine (L2-4), pelvis, legs, and total body were measured by dual-energy X-ray absorptiometry (DEXA). Results: Regional and total body BMD did not differ among women aged in their 20s, 30s, and 40s. However, in women aged over 50, regional and total body BMD gradually decreased with age. The strength of correlation of lumbar spine BMD with the left arm, right arm, left leg, right leg, and total body BMD gradually increased with advancing age ( r=0.422–0.715, 0.376–0.714, 0.476–0.721, 0.491–0.734, and 0.642–0.800, respectively). However, the strength of correlation of lumbar spine BMD with pelvis BMD remained unchanged ( r=0.512–0.622). Conclusions: Correlation of lumbar spine BMD with extremities BMD gradually strengthens with advancing age, while higher correlation of lumbar spine BMD with pelvis BMD remains unchanged. When lumbar spine BMD is predicted using values at sites such as forearm BMD, we should consider the patient's age.