L2-4 Bone Mineral Density Research Articles

RELATION OF ISOMETRIC STRENGTH TO BONE MINERAL DENSITY IN MIDDLE-AGED MEN: THE DNASCO-STUDY 577

Osteoporosis is a growing public health problem not only in women but also in ageing men. We analyzed the relation of isometric strength (IS) of the upper and lower extremeties with bone mineral density (BMD) in 140 men, aged 53 to 62 years. The data were derived from the baseline measurements of the 3-year DNASCO exercise intervention trial. IS of the arm and leg flexor and extensor muscles was measured using a computerized measurement system (HUR Ltd, Finland). BMD in lumbar spine (L2-4), femoral neck, triangle of Ward and trochanter was measured using dual energy X-ray absorptiometry. IS of the arm flexors and extensors correlated positively with BMD in L2-4 (r=0.31 and 0.38, p<0.001), in triangle of Ward (r=0.29 and 0.30, p<0.001) and in femoral neck (r=0.24, p=0.006 and 0.30, p<0.001). IS of the leg flexors and extensors correlated with BMD to a lesser extent, coefficients varying from 0.18, p=0.033 (femoral neck) to 0.23, p=0.007 (L2-4). Body weight (BW) correlated positively with BMD at all sites (r=0.24 to 0.38, p=0.004 to<0.001), and dietary calcium intake (adjusted for energy intake, mg/MJ) correlated positively with BMD at trochanter (r=0.35, p<0.001) and at femoral neck (r=0.25, p=0.003) levels. In multiple stepwise regression analysis, BW, IS of the arm extensors and calcium intake explained 16.2% and 23.5% of the variance in trochanter and femoral neck BMD, respectively. Arm extensors IS, BW and age were the strongest determinants of L2-4 BMD explaining 20.3% of the variance. The presence of absence of cardiovascular diagnosis or smoking were not associated with BMD. These data suggest that muscular strength is an important determinant of bone mineral density in middle-aged men. Moreover, isometric strength of the arm muscles, which is relatively easy to measure, seems to offer a good estimate of overall muscular strength.

Comparison of bone mineral density between athletic and non-athletic Chinese male adolescents.

For the evaluation of the effect of exercise on bone mineral density of adolescent athletes, twenty-nine Chinese male adolescent athletes, each of whom had regular training in his major sport which included baseball, swimming, judo and middle/long-distance running for one to six years and eight age-matched non-athletic controls were included in this study. Bone mineral density (BMD) was measured in all study subjects using dual photo absorptiometry at the second to fourth lumbar spines (L2-4) and the right femoral neck (FN). The results revealed the following: (1) the combined group of athletes had significantly greater BMD of L2-4 (1.08 +/- 0.09 g/cm2) than the control group (0.99 +/- 0.08 g/cm2) and a tendency for greater BMD of FN (1.15 +/- 0.13 g/cm2) than the control group (1.09 +/- 0.13 g/cm2); (2) judo majors had significantly greater BMD of L2-4 than baseball majors (P < 0.05), swimming majors (P < 0.01), track majors (P < 0.05) and controls (P < 0.005); (3) baseball majors had significantly greater BMD of L2-4 than controls (P < 0.05) and greater BMD of FN than swimming majors (P < 0.05), judo majors (P < 0.05), track majors (P < 0.005) and controls (P < 0.005); (4) body weight and body mass index (BMI) had good correlation with BMD of L2-4 and FN in control group, (5) in the combined group of athletes, weight and BMI were only strongly linked to BMD of FN, and not to BMD of L2-4. There was no good correlation between BMI and BMD of L2-4 and FN in any group of athletes. We concluded that (1) physical activity during adolescence may contribute significantly towards increasing BMD of athletes and (2) the training type may provide a specific stimulus for increasing BMD at specific localized sites experienced in training.

Decreased bone mineral density associated with early menopause progresses for at least ten years: Cross-sectional comparisons between early and normal menopausal women

To establish whether early onset of menopause carries an increased risk of osteoporosis, we compared the bone mineral density (BMD) of the second to fourth lumbar vertebrae (L2-4) between 18 women who had menopause before 43 years of age (early menopause group) and 19 women who had menopause after reaching 43 years of age (normal menopause group). Serum levels of calcium, phosphorus, calcitonin, intact parathyroid hormone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), and alkaline phosphatase activity were measured, and urine samples were analyzed to derive calcium/creatinine, hydroxyproline/creatinine, pyridinoline/creatinine, and deoxypyridinoline/creatinine (D-Pyr/Cr) ratios. Mean BMD was significantly lower in the early menopause group than in the normal menopause group, and individual BMD values in about half of the subjects in the former group were below the fracture threshold for Japanese women. Serum concentrations of LH, FSH, and E2 were slightly, but not significantly, lower in the early menopause group than in the normal menopause group. The D-Pyr/Cr ratio was significantly higher in the early menopause group than in the normal menopause group. There was no correlation between L2-4 BMD and age or the number of years after menopause in the normal menopause group, but both age and the number of years after menopause were negatively correlated with L2-4 BMD in the early menopause group. These results indicate that BMD in women who have early menopause continues to decline for up to 10 years, and that menopause and aging increase the risk of osteoporosis.

Bone mineral density of total body, spine, and femoral neck in children and young adults: A cross-sectional and longitudinal study

Bone mineral density (BMD) of total body (TBMD), lumbar spine (L2-4), and femoral neck was measured in 266 normal subjects (136 males) aged 4-27 years (mean 13 years) using dual-energy x-ray absorptiometry (DXA). BMD of all sites increased significantly with age until 17.5 years in males and 15.8 years in females, except for femoral neck BMD in females, which peaked at age 14.1 years. Males had higher peak TBMD, which was attributed to greater weight and lean tissue mass. In contrast, despite a later timing, peak L2-4 BMD in males was not different from that in females. Before peak BMD, weight was the best predictor of TBMD and L2-4 BMD in both sexes (r2 ranged from 0.77 to 0.88), whereas femoral neck BMD was predicted equally by height and weight. Longitudinal information collected from 53 (25 boys) of these children, aged 4-16.9 years, showed that the average annualized gain in TBMD was 0.047 g/cm2 for boys and 0.039 g/cm2 for girls. No significant difference in the association between age and BMD (slopes) was found between cross-sectional and longitudinal data for either sex. We conclude that the timing for peak BMD was consistent for total body, lumbar spine, and femoral neck for each sex. The earlier peak BMD in females is most likely related to earlier puberty. The cross-sectional normative data of this study are useful in serving as a standard for serial assessment in health and disease states.

Dual-energy X-ray absorptiometry of raloxifene effects on the lumbar vertebrae and femora of ovariectomized rats

A new potential therapeutic agent for postmenopausal osteoporosis, raloxifene, previously known as keoxifene, was evaluated by x-ray densitometry and more traditional techniques in quantitating the short-term (4-5 weeks) effects of ovariectomy on bones from 6-month-old rats. A Hologic QDR 1000/W and, to a limited extent, a Lunar DPXL, was used to quantitate ovariectomy, estrogen replacement, and raloxifene effects on vertebrae, femora, and tibiae. Both instruments performed well with precisions of 1.6% (Hologic) and 0.9% (Lunar) for anesthetized rats, which improved to 0.4% (Hologic) and 0.5% (Lunar) when the same rats were frozen. The lumbar vertebrae L1-4 showed a 12% decrease in bone mineral density 4 weeks after ovariectomy, compared with a 9% decrease for femora. Tibiae were also examined, but edge-detection problems prevented reproducible analysis of this site in vivo. The decrease in bone mineral density postovariectomy, especially for femora, was found to include both an increase in the projected area and a slight but not significant decrease in the bone mineral content of L1-4 and femora. These changes in density parameters of femora were supported by a decrease in dry weight and volume and a marginal increase in the second moment of inertia I for the identical femora examined ex vivo. Examination of individual lumbar vertebrae L1-5 suggested that the bone mineral density of L3 changes most dramatically in response to ovariectomy, but present techniques lack the spatial resolution and precision to quantitate bone changes reliably in individual vertebrae. 17 beta-Estradiol administered at 100 micrograms/kg/day subcutaneously inhibited ovariectomy effects on L1-4 bone mineral density, femoral moment of inertia, dry weight, and volume and to a lesser extent, femoral bone mineral density. A nonsteroidal compound, raloxifene HCl, at 1 mg/kg/day per os, had bone effects and effects on body weight that were largely indistinguishable from those of 17 beta-estradiol; however, raloxifene did not produce the uterotrophic effects observed with estrogen. The half-maximal efficacious dose of raloxifene on L1-4 bone mineral density was between 0.1 and 1.0 mg/kg/day per os. These data show that dual-energy x-ray absorptiometry compares favorably with traditional methods in quantitating bone changes caused by ovariectomy in small rodents, that L1-4 is a more sensitive region than whole femora in evaluating the effect of estrogen deficiency on bone loss, and the raloxifene may have promise as a treatment for conditions characterized by excessive bone loss after ovariectomy.

Distribution of bone mineral density in the lumbar spine in health and osteoporosis.

The significance of variability in bone mineral density (BMD) between lumbar vertebrae L1 to L4 in the same individual was investigated by dual-energy X-ray absorptiometry in 1000 normal women aged 40-60 years (average 52 years) and 145 women aged 45-80 years (average 65 years) with vertebral osteoporosis. The mean BMD increased from L1 to L4 in normal women from 0.841 g/cm2 to 1.017 g/cm2, and in osteoporotics from 0.562 g/cm2 to 0.709 g/cm2. Z scores for osteoporotic women (Z = osteoporotic BMD - age-normal BMD/normal SD) were significantly lower for individual vertebrae compared with L1-4 and at L4 compared with L1, L2 and L3 (p < 0.001). The mean difference between Z scores for the highest and lowest vertebrae in an individual was 0.70 for normals (SD = 0.40) and 0.64 for osteoporotics (SD = 0.36). The mean Z score difference between the L1-4 Z score and the lowest individual vertebral Z score was 0.36 for normals (SD = 0.23) and 0.06 for osteoporotics (SD = 0.31). However, receiver operating analysis (ROC) curves showed that the lowest Z score for any individual vertebra did not provide improved discrimination between normals and osteoporotics when compared with the L1-4 Z score. The area under the ROC curve for L1-4 was significantly greater than for individual vertebrae (p < 0.05) and that for L4 was significantly smaller than for L1, L2 or L3 (p < 0.001). In conclusion, L1-4 BMD gives greater diagnostic sensitivity for osteoporosis than individual vertebrae, and L1, L2 and L3 are better than L4.(ABSTRACT TRUNCATED AT 250 WORDS)

The spinal bone fracture of the aged women

The deformity or fracture of the spines, bone mineral density (BMD) of radius and spines by anterior-posterior scans and lateral scans, and metabolic bone markers were examined in the old women. The probability of fracture was less than 10% in women with L3 BMD over 0.786g/cm2, and new fractures were not found during 12 months follow-up in these patients. Among the various metabolic parameters, bone Gla protein (BGP)/hydroxyproline (Hp) excretion ratio was one of the clinically useful indices if combined with BMD. The intensive therapy may not be necessary to patients with low BMD if they show high BGP/Hp ratio. Patients with low BMD and low BGP/Hp ratio should be treated intensively in the old women.

Impact of anomalous vertebral segmentation on measurements of bone mineral density

In anteroposterior (AP) bone mineral density (BMD) measurements of the lumbar spine (LS), the presence of ribs is used to identify vertebra T12. Similarly, in lateral LS-BMD measurements, the position of the iliac crest is used to identify the lumbar vertebrae. The aim of this study was to determine the impact of variations in spinal segmentation and iliac crest position on BMD measurements. In 375 women (ages 50-85 years) radiographs were taken of the thoracic and lumbar spine, as well as AP measurement of LS-BMD, by dual-energy x-ray absorptiometry (DXA). In 121 subjects lateral decubitus LS-BMD was also measured. Anomalous spinal segmentation was found in 16.5%, and L1 would have been incorrectly identified on the AP-DXA image in 13%. The change in BMC and BMD between adjacent vertebrae was greater in the upper than the lower lumbar spine. Misidentification of L1 for T12 resulted in underestimation of the bone mineral content in grams (BMC) of L1 by a mean of 11.5 +/- 14.4% (SD; range -33.5 to 33.5%). For the usual region of interest, L2-4, the BMC (g) was underestimated by 8.4 +/- 8.7% (range -1.5 to 29.2%), with the BMD (g/cm2) underestimated by 3.6 +/- 4.8% (range -5.4 to 11.6%). The position of the iliac crest on the lateral decubitus DXA scans would have led to misidentification of either L2 or L4 for L3 in 15 cases (12%). This resulted in the BMD of L3 being underestimated by 2.7 +/- 19.4% (range -242.4 to 34.6%).(ABSTRACT TRUNCATED AT 250 WORDS)

ＤＥＸＡによるけい椎骨密度の測定

This study investigated whether cervical bone mineral density (BMD) measured by Dual-Energy X-Ray Absorptiometry (DEXA) was a reliable parameter for estimation of local bone metabolism of the cervical spine in patients with symptomatic cervical disorders.We examined the reproducibility of quantifying cervical BMD by DEXA, and cervical BMD was compared with lumbar and right femoral neck BMD. Cervical BMD was measured in 23 normal females. The precision of lateral BMD measurement of the cervical spine by DEXA (CV=2.77%) was as good as that of the lumbar spine and right femoral neck (respectively, CV=2.02% and 2.37%). Age-related BMD changes seen between 20 and 60 years of age in cervical spines were similar to those in the lumbar spines. Correlation between C5 BMD and L3 BMD was highly significant in normal females (r=0.67, p<0.001).These results suggest that cervical BMD reflects the general bone mineral content movement. Therefore, we concluded that DEXA can be a powerful tool for estimation of local bone mineral content movement of cervical spine.

Precision and sensitivity of dual-energy X-ray absorptiometry in spinal osteoporosis

This study evaluated the performance of dual-energy x-ray absorptiometry (DEXA) with regard to (1) the correlation with dual-photon absorptiometry (DPA), (2) the ability to discriminate between normal and osteoporotic patients, and (3) long-term reproducibility. The bone mineral density (BMD) of the spine in 112 subjects, both normal and osteoporotic, was measured with DPA and DEXA (Lunar Corporation, Madison, Wisconsin) of the spine. The femur BMD of 22 cases was also measured with both machines. The results for the two techniques were highly correlated (r greater than 0.9, SEM = 0.02 to 0.04 g/cm2). BMD was measured using DEXA in 80 women (mean age = 61 years) with established spinal osteoporosis and 110 normal age-matched controls. The osteoporotic patients had significantly reduced spine and femur BMDs compared to the controls: -23% for L2-4 BMD (Z score = 2.6) and -13 to -20% for femur BMD (Z score = 1.1-1.3). L2-4 BMD had the best discriminative value, with an area under the ROC curve of 94%; the Ward's triangle BMD had an area of 84%. The precision error in vitro in a phantom over a 1-year period was 0.7%. The measured precision in vivo with young adults was approximately 1% (SD = 0.012 g/cm2) for L2-4 BMD and 1.7-2.3% (SD = 0.015-0.022 g/cm2) for femur over the 1 year period. The reproducibility was not as good for osteoporotic patients (SD = 0.017 g/cm2).

Cross calibrated standard values of vertebral bone mineral density in Japanese

The reference value of L2-4 bone mineral density (BMD) was calculated in Japanese population by using cross-calibration formulae among the different types of dual energy X-ray absorptiometry (DEXA) and dual photon absorptiometry (DPA). The scan data of lumbar spine were collected from 16 institutes equipped 3 types of DEXA and 3 types of DPA. After subtraction of inadequate scan data, a total of 1038 cases (376 males and 662 females) were accepted to be a representative “normal” population of Japanese. The L2-4 BMD values were adjusted to one equipment by using cross-calibration equations. There were significant decrease in L2-4 BMD in both sexes at age of seventies or more (9.5% decrease in males and 27.5% in females from the peak bone density). When the cut-off value of L2-4 BMD set to 0.8 g/cm2 (QDR), 0.88 (DPX) and 0.77 (XR), 80% of correct discrimination between “normal” and osteoporotics was achieved in the forties and the fifties. Therefore, these values can utilize to diagnose early bone loss. There was significant correlation between L2-4 BMD value and the total score of criteria for involutional osteoporosis. In summary, the BMD values obtained by cross-calibration in the different equipments might be acceptable for the reference value of Japanese population as well as for the detection of early bone loss, tentatively. Further investigations are currently undergoing.

Relationship Between Trunk Muscle Torque and Bone Mineral Content of the Lumbar Spine and Hip in Healthy Postmenopausal Women

The purpose of the study was to determine the relationship between trunk muscle strength and bone mineral density (BMD). Fifty-six postmenopausal women, aged 38 to 73 years, were examined. The BMD of lumbar vertebrae L2-4, the femoral neck, the Ward's triangle, and the greater trochanter was measured with dual-photon absorptiometry. Isometric and isokinetic torque and work measurements obtained on a trunk testing unit were used to assess trunk flexor and extensor strength. Correlation analysis demonstrated a statistically significant relationship between most trunk torque and work measurements and BMD. The trunk extensors generally provided higher correlations with BMD than did the trunk flexors, and the isokinetic extension torque values demonstrated higher correlations than the isometric extension values in every case. Linear backward-regression models, based on the subjects' weight and trunk flexor and extensor torque and work measurements, demonstrated multiple-correlation coefficients of .67, .58, .43, and .65 in predicting the BMD of the L2-4 region, femoral neck, Ward's triangle, and greater trochanter region, respectively. Estrogen therapy status did not affect the linear regression models. These data suggest a positive relationship in postmenopausal women between flexor and extensor torque values and BMD at the lower lumbar spine and proximal femur.

Synchronized ventilatory support and hypercarb

The aim of this study was to explore the relationship between maximal oxygen consumption (VO2 max) and bone mineral density (BMD) in a group of young Lebanese adults. Twenty women and 37 men whose ages range from 18 to 32 yr participated in this study. Informed written consent was obtained from the participants. Body weight and height were measured, and body mass index was calculated. VO2 max was determined by direct measurement while exercising on a bicycle ergometer (Siemens-Elema RE 820; Rodby Elektronik AB, Enhorna, Sweden). Whole body bone mineral content (WB BMC), whole body bone mineral density (WB BMD), lumbar spine BMD (L1–L4 BMD), total hip BMD (TH BMD), and femoral neck BMD (FN BMD) were measured by dual-energy X-ray absorptiometry. In women, VO2 max (expressed as L/mn) was positively correlated to WB BMC (r = 0.82; p < 0.001), WB BMD (r = 0.80; p < 0.001), L1–L4 BMD (r = 0.73; p < 0.001), TH BMD (r = 0.80; p < 0.001), and FN BMD (r = 0.85; p < 0.001). In men, VO2 max (expressed as L/mn) was positively correlated to WB BMC (r = 0.57; p < 0.001), WB BMD (r = 0.53; p < 0.001), L1–L4 BMD (r = 0.50; p < 0.001), TH BMD (r = 0.38; p < 0.01), and FN BMD (r = 0.30; p < 0.05). In both sexes, the positive associations between VO2 max and bone variables (BMC and BMD) remained significant after adjustment for age (p < 0.001). This study suggests that VO2 max (L/mn) is a positive determinant of BMC and BMD in young adults. Aerobic power seems to be a determinant of BMC and BMD in young adults.