Bone changes occurring spontaneously and caused by estrogen in early postmenopausal women: a local or generalised phenomenon?

The relative contributions of menopause and aging to postmenopausal reduction in intervertebral disk height

AIM

To evaluate, in a population of normal women, the effects of aging and menopause on the height of intervertebral discs by measuring the intervertebral disk space, between the 12th thoracic and 4th lumbar vertebrae, by dual-energy X-ray absorptiometry (DXA).

MATERIALS AND METHODS

The study was conducted on 2455 consecutive women attending our Department, from whom 464 normal women were selected. The measurement was validated utilizing a spine phantom.

RESULTS

The phantom mean intervertebral disk space was 0.44 cm, with a coefficient of variation of 1.4%. The coefficients of variation in premenopausal, early postmenopausal and elderly women were 2.2, 2.0 and 6.0%, respectively. Values of intervertebral disk space were stable from age 20 to 50 years, thereafter showing a significant (p < 0.05) decrease, negatively correlated with both age and years since menopause (p < 0.0001). In postmenopausal women younger than 60 years, a correlation (p = 0.042) was evident between intervertebral disk space and years since menopause, but no correlation was evident with age. In women over 60 years, no correlations were found between intervertebral disk space and either age or years since menopause. In three groups of age-matched women (47.5 +/- 1.5 years, n = 39 in each group), intervertebral disk space was significantly (p < 0.0001) lower in postmenopausal than in both premenopausal and perimenopausal women.

CONCLUSION

The DXA measurement of intervertebral disk space is precise. After menopause, intervertebral disk space shows a progressive decrease that almost entirely occurs in the first 5 - 10 years since menopause, suggesting that the estrogen decrease may rapidly change connective tissue metabolism in the intervertebral disks.

The effect of bilateral oophorectomy on bone mineral density

The objective of this study is to investigate the effect of bilateral oophorectomy with total abdominal hysterectomy on bone loss, comparing the cases having surgery before and after the menopause. Bone mineral density (BMD) measurements were obtained from the lumbar spine and femoral neck of totally 127 cases. Out of 127, 105 had surgery before menopause and 22 cases were operated on postmenopausally. The results were compared with the USA normal values. The average age of surgical menopause (SM) cases was 48.45 years with a mean duration of menopause of 5.77 years. The average height and weight were 157.67 cm and 68.19 kg, respectively. The average age of cases having surgery after menopause (SAM) was 62.45 years with a mean duration of 5.59 years after the surgery (duration after menopause is 13.23 years). The average height and weight were 157.45 cm and 73.55 kg, respectively. The average of BMD measurements of lumbar spines L2-L4 was 1.04 gr/cm(2) (BMD = 85.65% and T score = -0.96) in the cases with SM. On the contrary, the average of the BMD measurements of lumbar spines L2-L4 was 1.05 gr/cm(2) (BMD = 101.14% and T score = 0.24) in the cases with SAM. The average of the BMD measurements of femoral neck was 0.85 gr/cm(2) (BMD = 91.39% and T score = -0.64) in the cases with SM. On the contrary, the average of the BMD measurements of femoral neck was 0.82 gr/cm(2) (BMD = 96.69% and T score = -0.31) in the cases with SAM. The bilateral oophorectomy as a surgical procedure is not a statistically significant factor for the acceleration of the bone loss. The main points are the age and the duration of menopause of the patient affecting the bone loss if the surgery is performed before menopause.

The course of bone mineral density and biochemical markers of bone turnover in early postmenopausal spinal cord-lesioned females

STUDY DESIGN

A prospective observational study.

OBJECTIVE

To evaluate bone mineral density (BMD) and biochemical markers of bone turnover in spinal cord-lesioned females in the early postmenopausal period.

SETTING

Clinic for Spinal Cord Injuries, H:S Rigshospitalet, Denmark.

MATERIAL

In all, 18 early postmenopausal females with spinal cord lesions (SCL) of more than 2 years duration were recruited. In total, 11 completed the study.

METHODS

Using dual energy X-ray absorption, BMD of the lumbar spine, femoral neck, trochanter and proximal tibia was measured every 6 months for 30 months. Biochemical markers of bone turnover in blood and urine were collected at the same time points.

RESULTS

A significant increase in markers of bone formation in the blood was found and markers of bone resorption in urine tended to increase. BMD values changed insignificantly but for all regions decreased, except the lumbar spine.

CONCLUSION

An accelerated bone turnover occurs in early postmenopausal SCL females. At the same time, we showed an insignificant decrease in BMD data from the lower extremity.

Age and menopause-related changes in phalangeal bone density of Japanese women, measured by a digital image processing method

The bone density (BD), phalangeal index (PLI), and metacarpal index (MCI) of the proximal phalangeal and metacarpal bones of the index finger of the nondominant hand were measured, using a digital image processing (DIP) method, in a total of 345 normal Japanese women. In this study, two different locations were measured and the BD, PLI, and MCI decreased significantly after the age of 50 years (P < 0.01 vs values for women in their third decade). The BD, PLI, and MCI of the proximal phalangeal and metacarpal bones showed a significant decrease in postmenopausal groups compared with the pre-menopause group (P < 0.01), which indicated that not only trabecular bone but also cortical bone had an accelerative bone loss in the postmenopausal women. The BD in proximal phalangeal and metacarpal bones decreased by 0.69% and 0.74% / per year, respectively, and there were no significant differences between these annual decreases. The BD of proximal phalangeal bone had a good correlation with that of the metacarpal bone (r = 0.77; P < 0.01), which suggested that the measurement of proximal phalangeal BD was as useful as the measurement of metacarpal BD in screening for osteoporosis (coefficient of variation; CV, 0.64%). The data suggest that DIP has a potential application in screening for osteoporosis.

Cross-sectional and longitudinal assessment of pre- and postmenopausal bone loss with a portable forearm X-ray device: the Ofely study

The aim of our study was to describe cross-sectional and longitudinal bone mineral decrease in pre-, peri-, and postmenopausal healthy women using a monoenergy X-ray densitometer specifically designed for forearm assessement. Measurements were performed on the most distal part of the radius (ultradistal, 55% of trabecular bone and 45% of trabecular bone), and on the distal part (distal, 13% of trabecular bone and 87% of cortical bone). A specific trabecular-rich region of interest (nROI) comprising two trapezoids regions of interest located proximally to the endplates of the radius and ulna was also investigated. From a large prospective study (OFELY study), 455 women were measured once a year for 2 years (three measurements). The proportion of postmenopausal women classified as having osteoporosis (i.e., a T score <-2.5) was 33% for the distal region, 44% for the ultradistal region, and 45% for the nROI. No significant bone mineral decrease was found over the 2-year period in premenopausal women (n = 138). In perimenopausal (n = 48) women, a bone loss of 1% was found at the distal site. In the 269 postmenopausal women, a significant decrease was observed at all sites, ranging from 2.14% for the nROI to 2.68% for the ultradistal part. Bone loss was greater in the first 5 years after menopause in trabecular sites and decreased thereafter. For the distal site, bone loss remained stable during the postmenopausal period. We conclude that this small and portable forearm densitometer is suitable for the diagnosis of osteoporosis, and provides information on the rate of bone loss in peri- and postmenopausal women in trabecular and cortical compartments of bone.

Sex steroids, bone turnover and bone mineral density in pre-, peri-, and postmenopausal women

To examine 1) the relationships between endogenous androgens and bone mineral density (BMD), 2) the relationships between sex-hormone binding globulin (SHBG) and BMD, and 3) the associations of endogenous androgens and SHBG with biochemical markers of bone turnover, a cross-sectional study was carried out in 88 healthy pre-, peri-, and postmenopausal women aged 35 to 74. Measurements of BMD(s) at the ultradistal radius and ulna, and the distal radius (using DEXA), estrogens, androgens, deoxypyridinoline (D-Pyr) and intact bone gla protein (I-BGP) were performed. In the multivariate regression models testosterone (T) was positively correlated with BMD at the ultradistal radius and ulna in perimenopausal women, and was positively correlated with BMD at the ultradistal radius and ulna, and the distal radius in postmenopausal women. T was positively associated with I-BGP in premenopausal women (r = 0.65, p < 0.01), and negatively associated with D-Pyr in pre- (r = -0.53, p < 0.05) and postmenopausal women (r = -0.49, p < 0.001). On the other hand, SHBG was negatively correlated with BMD at die ultradistal radius and ulna, and die distal radius in pre- and postmenopausal women in the models. SHBG was positively related to D-Pyr in pre(r = 0.57, p < 0.05) and postmenopausal women (r = 0.41, p < 0.01), and negatively related to I-BGP in postmenopausal women (r = -0.38, p < 0.01). These findings suggest that endogenous androgens may exert positive influences on BMD, and that SHBG may have negative effects on BMD.

Hormone replacement therapy and osteoporosis

Restoration of the osteoporotic skeleton is difficult. Factors that may aggravate the bone loss or increase the risk of fractures should be eliminated. The physician may then decide whether the patient is a candidate for one of the treatments which either stop further bone loss or increase the bone mass. The decision should be based on a variety of factors and be taken together with the patient.

Post-menopausal hormone use and tooth loss: a prospective study

Nearly 32 percent of U.S. women aged 65 to 69 years have no teeth. Because some tooth loss may reflect systemic osteoporosis, and because estrogen therapy seems to protect against osteoporosis, the authors examined the risk of tooth loss in relation to hormone use in a prospective study of 42,171 post-menopausal women. The risk of tooth loss was lower in women who currently used hormones. Although few studies have examined this issue, this research suggests that estrogen may reduce tooth loss.

Randomized cross-over study of a 21-day versus a 28-day hormone replacement therapy (HRT)

OBJECTIVE

To compare the occurrence of climacteric symptoms at two points in the cycle, identified as minE (phase of minimum estrogen effect) and MaxP (phase of maximum progesterone effect).

METHODS

Prospective randomized cross-over study in postmenopausal women currently on HRT comparing two opposed, sequential formulations: a regimen of 21 tablets containing estradiol valerate (EV) opposed with cyproterone acetate (CPA) in the last 10 tablets, versus a regimen of 28 tablets of conjugated equine estrogens (CEE), the last 12 tablets of which were taken together with norgestrel (NG).

OUTCOME MEASURES

Incidence of 24 climacteric complaints assessed at the specified days of the cycle corresponding to minE (day 6 or 7) and MaxP (day 27 or 28)

RESULTS

Contrary to the hypothesis that estrogen-dependent symptoms will recur at minE of the 21-day regimen, no significant differences were noted with the regimen containing 28 days of CEE, which served as the control. There were more complaints with the CEE+NG formulation at both minE and MaxP. Of the 38 patients, 63% preferred the EV+CPA regimen, 18.4% the CEE+NG regimen and 18.4% rated both preparations as equal.

CONCLUSIONS

The 7-day pause in the 21-day formulation containing EV+CPA did not affect efficacy; it was as effective in relieving climacteric symptoms as the regimen containing 28 days of estrogen. Based on the frequency of complaints both at minE and MaxP, the EV+CPA formulation induced a more acceptable symptom and mood profile.

Heel ultrasound in women after long-term ERT compared with bone densities in the forearm, spine and hip

To compare heel ultrasound values with bone densities at different measurement sites as determined by single photon absorptiometry (SPA) and dual-energy X-ray absorptiometry (DXA) in long-term users of estrogen replacement therapy (ERT), we analyzed data from 30 users of estradiol implants (mean duration of treatment 16 years) and 32 non-users, comprising 28 complete age-matched pairs. The precision errors in vivo of ultrasound measurements were 0.18%, 1.3% and 1.5% for speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index, respectively. In the controls, ultrasound parameters correlated well with values from SPA and DXA measurements (r = 0.51-0.63, p < 0.004). In long-term users of ERT, however, measurements with ultrasound did not correlate with DXA in the spine and hip (r = 0.01-0.31, NS) but correlated well with SPA in the forearm (r = 0.47-0.66, p < 0.009). Implant users, compared with non-users, had small and just significantly different values when measured by ultrasound (at most 12%, p = 0.03-0.04) but significantly higher bone mineral densities (18%-25%, p = 0.0001-0.01) in the forearm, spine and hip when measured by SPA or DXA. Data indicated that a substantial proportion of long-term users of estrogen may be non-responders concerning the effect of estrogen on bone qualities expressed in heel ultrasound values. In a multivariate regression analysis the effect of increasing age and increasing treatment duration were both negative for the ultrasound parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Low bioavailable testosterone levels predict future height loss in postmenopausal women

The objective of this study was to examine the relation of endogenous sex hormones to subsequent height loss in postmenopausal women, in whom height loss is usually a surrogate for osteoporotic vertebral fractures. This was a prospective, community-based study. The site chosen was Rancho Bernardo, an upper middle class community in Southern California. A total of 170 postmenopausal women participated, aged 55-80 years. None of them were taking exogenous estrogen between 1972 and 1974. Plasma was obtained for sex hormone and sex hormone-binding globulin (SHBG) assays. Estradiol/SHBG and testosterone/SHBG ratios were used to estimate biologically available hormone levels; bioavailable (non-SHBG-bound) testosterone was measured directly in 60 women. Height loss was based on height measurements taken 16 years apart. Height loss was strongly correlated with age (p = 0.001). These women lost an average 0.22 cm/year in height. Neither estrone nor estradiol levels were significantly and independently related to height loss. Both estimated bioavailable testosterone (testosterone/SHBG ratio) and measured bioavailable testosterone levels predicted future height loss (p = 0.02 and 0.08, respectively) independent of age, obesity, cigarette smoking, alcohol intake, and use of thiazides and estrogen. We conclude that bioavailable testosterone is an independent predictor of height loss in elderly postmenopausal women. The reduced height loss is compatible with a direct effect of testosterone on bone mineral density or bone remodeling.

Non-responders to hormone replacement therapy for the prevention of postmenopausal bone loss: do they exist?

Hormone replacement therapy (HRT) prevents postmenopausal bone loss, but the prevalence of non-responders in healthy early postmenopausal women is not known. In order to study this, we reviewed data from three published studies, each carried out in a randomized, placebo-controlled, longitudinal design over 2 year, that used seven hormone replacement therapies. Bone mineral content (BMC) was measured in the distal forearm by single photon absorptiometry. A mathematical model for elimination of measurement errors was applied to published BMC data. After this correction, we found that only 1.2% of early healthy postmenopausal women who are receiving HRT in conventional doses will lose more than 1% of forearm BMC per year. In conclusion, most, if not all, healthy early postmenopausal women who might need HRT against loss of bone will respond positively in forearm BMC to such therapy.

The relationship of total body bone mineral (TBBMC) to anthropometric variables in postmenopausal women, and contribution of chronological age and years since menopause to TBBMC loss

Dual energy X-ray absorptiometry measurements of total body bone mineral content (TBBMC), fat body mass (FBM) and fat mass percentage (%FM), lean body mass (LBM) and body weight (BW) were performed on 168 normal postmenopausal females. They were matched regarding life style and habits and had body mass index under 30. Their TBBMCs were correlated with these measurements, with chronological age (CA) and with the number of years since menopause (YSM). There was no correlation between TBBMC and %FM and LBM, but there was with BW (p < 0.001). There was a significant and negative correlation (r = -0.453, p < 0.001) between TBBMC and CA and to a higher range (r = -0.697, p < 0.001) with YSM. Menopausal females over 60 (n = 87) presented less bone mass than younger females (n = 81) (p < 0.01). These data suggest that regarding TBBMC, menopausal onset is a more important factor in bone mass loss, which persists rather markedly even during periods of time far from menopause and that TBBMC depends more on BW than on LBM and FM in women.

Hormone replacement therapy prevents bone loss in patients with inflammatory bowel disease

Patients with inflammatory bowel disease have an increased prevalence of osteoporosis, and suffer high rates of spinal bone loss. Hormone replacement therapy (HRT) is effective in the treatment and prevention of osteoporosis but has not been studied in patients with inflammatory bowel disease. A two year prospective study of HRT in inflammatory bowel disease was performed in 47 postmenopausal women aged 44 to 67 years with ulcerative colitis (25) or Crohn's disease (22). Patients had radial and spinal bone density measured annually by single photon absorptiometry and quantitative computed tomography respectively. The mean (95% confidence intervals) annual change in radial bone density was +1.42%/yr (+0.58 to +2.26; P < 0.005) and for spinal bone +2.60%/yr (+1.06 to +4.15; p < 0.005). There was no significant correlation between rates of change of bone density at the two sites, or between the rates of change and the initial bone density either in the radius or spine. Twelve patients were given prednisolone during the study, and their rates of change for spinal bone density were lower, but values were not statistically significantly different from those who did not receive corticosteroids. Changes in bone density for patients with ulcerative colitis and Crohn's disease were not significantly different. The change in bone density did not correlate with the patients' age or number of years after the menopause. It is concluded that HRT is effective in prevention of bone loss in postmenopausal women with inflammatory bowel disease.

Tamoxifen as adjuvant therapy in breast cancer. Current status

Tamoxifen retains its place as the most important drug in the management of human breast cancer. As time passes, it becomes clear that this drug is no longer to be regarded as a simple antiestrogen, since it modifies other cellular signalling mechanisms, giving scientific credence to the growth inhibitory effects observed in estrogen receptor-negative tumours. With the role of tamoxifen in breast cancer being well documented, recent interest has concentrated on its now proven efficacy in adjuvant treatment of patients with the disease in its early stages, and on its prophylactic role in women at high risk of developing the disease. For tamoxifen to have any role at all in the latter situation, it must be demonstrably safe, and here again the toxicity profile is now much better understood.

Cross-sectional and longitudinal study of age-related phalangeal bone loss in adult females

To establish a comprehensive model for peripheral phalangeal bone loss, bone mass was studied in 1984 and 1989 using quantitative microdensitometry (QMD) in a total of 330 healthy women (age range 43-78.7 years). Bone mass and changes in bone mass were analyzed in relation to age and menopausal status. Ideal and nonideal populations were distinguished to assess the effect of diseases and medication. Both groups showed a decrease in bone mass, which proved to be more dependent on menopausal status than on age. A substantial loss started in the ideal group in the early postmenopausal period and in the nonideal group in the premenopausal period. Because the nonideal group started to lose bone at an earlier stage, the lifetime risk for osteoporosis is higher than in the ideal group.

Endogenous sex hormones and bone mineral density among community-based postmenopausal women

In order to describe the relationships between endogenous sex hormones and bone mineral density in healthy postmenopausal women, we carried out a cross-sectional study of 90 community-based women, all at least one year since their last menstrual period (mean 9.6 +/- 4.9 years, range 1-22) and with a serum oestradiol level less than 100 pmol/l. None was currently using hormone replacement therapy. Serum oestradiol, testosterone, sex hormone binding globulin, dehydroepiandrosterone sulphate, and androstenedione were measured using standard techniques. Free oestradiol and testosterone indices were derived as the ratio of total hormone to sex hormone binding globulin, respectively. Total body, spine and hip bone mineral density (g/cm2) were measured by dual energy X-ray absorptiometry. Significant positive correlations were found between the free oestradiol and testosterone indices and bone mineral density at all sites. These relationships remained significant for the free oestradiol index after adjustment for age and body mass index. By stepwise multiple regression analysis, the free oestradiol index was an independent predictor of total body, spine and hip bone mineral density, accounting for 4-17% of the variance. These findings suggest an independent positive relationship between endogenous free oestradiol and total body, spine and hip bone mass even in the late postmenopause.

Postmenopausal hormone replacement therapy prevents central distribution of body fat after menopause

The reduction in cardiovascular risk induced by hormone replacement therapy is only partly explained by changes in serum lipids and lipoproteins. As body composition and body fat distribution in particular are independent predictors of cardiovascular disease, we investigated the effect of postmenopausal hormone therapy on body composition parameters directly measured. Sixty-two early postmenopausal women were followed up for 2 years in a prospective, randomized, placebo-controlled study. We found that combined estrogen-progestogen therapy prevented the increase in abdominal fat after menopause (P less than .05), and that this effect was independent of the effect on serum lipids and lipoproteins. The therapy reduced postmenopausal bone loss significantly (P less than .001), whereas it did not have a statistically significant influence on total body fat mass or total lean body mass. The findings of the present study suggest that some of the protective impact of postmenopausal hormone therapy on cardiovascular disease may be explained by the effect on body composition, in particular abdominal fat.

Estrogen therapy and variable-resistance weight training increase bone mineral in surgically menopausal women

This study was undertaken to examine the effect of estrogen replacement therapy alone and estrogen replacement therapy plus variable-resistance weight training on the bone mineral content of surgically menopausal women. A total of 20 surgically menopausal women were randomized and treated with either 0.625 mg conjugated estrogen daily or the same dose of estrogen plus a closely monitored exercise program involving the use of Nautilus muscle strengthening/endurance equipment. After 1 year's observation, the bone mineral density (BMD) of the spine determined by dual-photon absorptiometry increased in the exercising subjects by 8.3 +/- 5.3% (p = 0.004), 95% confidence limits (CL) 3.9-12.8%; the group with estrogen replacement therapy alone maintained their BMD: 1.5 +/- 12.4% (p = 0.36; 95% CL = -6.9-9.8%). The total body BMD of the exercising group increased by 2.1 +/- 1.5% (p = 0.003; 95% CL = 0.8-3.3%); the nonexercising women had a nonsignificant 0.6 +/- 2.9% change (p = 0.30; 95% CL = -1.4-2.5%). A significant increase of 4.1 +/- 4.3% (p = 0.01; 95% CL = 0.8-7.4%) in the radial midshaft BMD of the exercising group was found; the estrogen alone group recorded a nonsignificant change of -0.3 +/- 3.1% (p = 0.33; 95% CL = -1.7-2.4%). The results of this study suggest that variable-resistance training in estrogen-replete women adds bone to both the axial and appendicular skeleton.

Rapid postmenopausal loss of total body and regional bone mass in normal southern Chinese females in Hong Kong

Osteoporosis is a major health problem in Hong Kong, affecting about 200,000 patients among a population of 6 million. To evaluate the rate of bone loss and determinants of low bone mass among the Southern Chinese, we measured the total body and regional bone mass with the XR-26 dual-energy X-ray absorptiometry in 90 normal females. The results show that the total and regional bone densities were stable before menopause, with a change of around 0.5% every year. After menopause, a rapid loss is evident for total body and regional bone mass. The rate of bone loss varies from 1.2% for the pelvis to 3.1% for the Ward's triangle per year. Thus, by the age of 70, most Southern Chinese females would have lost at least 25% of their bone. Age, body weight, and skeletal area are important determinants for the total body bone mass. Bone densities in weight-bearing regions, including hip, pelvis, spine and legs correlate strongly with each other (r = 0.68, P less than 0.001). Correlation is poor among unrelated regions, such as between head and arms (r = 0.39, P greater than 0.5). To conclude, normal Chinese women in Hong Kong lose bone rapidly after menopause at a rate of about 2% per year. This may account for the major incidence of osteoporosis-related complications in Hong Kong.

Bone density measurements

Early diagnosis of osteoporosis is difficult. Bone density measurements, however, are helpful in screening patients at risk. Technology now provides means of measuring densities of both peripheral and central bones. The most practical method is dual X-ray densitometry, which is of good sensitivity and accuracy. Single photon absorptiometry on peripheral bones can be used to screen populations at risk. Computed tomography is also useful but the radiation dose is relatively high. In dual X-ray densitometry, calibration methods and comparisons with reference values are fairly reliable. The best sites for measurements are the lumbar spine and proximal femur, in which osteoporotic fractures are common. In general, however, one measurement is not enough. Biological variation is great. Repeated measurements will allow estimation of the rate of bone loss. Precise location of a previous site is sometimes difficult on reexamination and extraskeletal calcifications can be sources of error. Bone densitometry in connection with the prevention and treatment of osteoporosis is fairly easily performed with a single patient. Knowledge about the correlation between bone density and fracture risk is not yet adequate. The results of measurement of bone mineral density relate only to mineral content, not bone quality, i.e., differential diagnosis of osteoporosis and osteomalacia is not possible.

Hormonal replacement therapy and the skeletal system

The two most important risk factors for maintaining skeletal health are the bone mass obtained at skeletal maturity (peak bone mass) and the subsequent bone loss. Those women with a low peak bone mass and a rapid bone loss are thus at increased risk of developing osteoporosis in the future, and should be identified. This may be accomplished by determination of the bone mass combined with an estimate of the rate of the postmenopausal bone loss. The bone mass can be accurately assessed in the forearm by single photon absorptiometry. The postmenopausal bone loss can be estimated by three or four biochemical markers of bone turnover. The women at highest risk of developing osteoporosis should be offered preventive therapy, e.g., hormonal replacement therapy (HRT). HRT arrests the bone loss not only in early, but also in elderly postmenopausal women. The effect lasts as long as the therapy is continued. Several epidemiological studies have demonstrated that HRT decreases the number of osteoporotic fractures.

Bone mass measured by photon absorptiometry: comparison of forearm, heel, and spine

We assessed bone mass quantification at different skeletal sites by single and dual photon absorptiometric (SPA and DPA) methods. Improved DPA measurement of spinal bone mineral density in young healthy subjects showed a short- and long-term precision of 1.2% and 1.6%. Compared to the conventional DPA method the imprecision was reduced by more than 50%. The appendicular measurements were more precise (0.5-1.2%). We present the intercorrelations and predictive errors between peripheral measurements and improved spinal and total body bone measurements in early postmenopausal women (n = 144) recruited in 1988. To compare the improved system with the conventional methods, we retrieved data on age-matched early postmenopausal women (n = 151) recruited in 1983. In the 1988 population all peripheral methods had similar predictive errors in estimation of spinal bone mineral density (SEE = 11-13%) and total body bone mineral density (SEE = 4-5%). Measurement of trabecular bone in the heel and distal forearm did not improve the validity of predicting spinal bone mass. In a cadaver study (n = 11) the predictive error in estimation of the spinal ash weight from forearm measurements was of the same magnitude (15%) as that in estimation of the spinal BMC from the forearm (16%). We conclude that the predictive error in estimation of spinal bone mass from peripheral bone measurements is more likely to be caused by intra-skeletal variation in bone mass than by precision errors. However, this does not reflect the inability of peripheral bone mass measurements to predict fracture risk.

Does a single local absorptiometric bone measurement indicate the overall skeletal status? Implications for osteoporosis and osteoarthritis of the hip

Regional bone mineral content (BMC) and density (BMD) (head, arms, chest, spine, pelvis, legs) of a total body dual photon 153Gd absorptiometry (DPA) scan were measured in 20 healthy postmenopausal women, 27 postmenopausal women with hip fracture, and 17 postmenopausal women with osteoarthritis of the hip. In addition, local BMC and BMD were measured in the proximal and distal regions of the distal forearm (BMCprox, BMDprox, BMCdist, BMDdist) by single photon absorptiometry (SPA); and in the lumbar spine (BMCL2-L4 and BMDL2-L4) by 153Gd DPA. The overall impression was a reduction of bone mass in hip fracture patients compared with healthy controls and an increase in the bone mass of osteoarthritic patients. These results were valid using both regional values of the total body scan, and local forearm and lumbar spine measurements, and statistically significant using one-way analysis of variance. There were, however, also significant within-group between-region differences (one-way analysis of variance), showing that the bone mass of the pelvis and legs in hip fracture patients was more reduced than in the remaining skeleton; in osteoarthritic patients it was not increased but rather unchanged or slightly reduced. The differences between the level of the three local measurements (BMDprox BMDdist BMDL2-L4), on the one hand, and the level of the six regional BMD values, on the other hand, were investigated by the two-way analysis of variance: local measurements = rows; regional values = columns. This analysis showed that none of the three local measurements was statistically better than the other two in predicting the overall level of skeletal bone mass as judged by the six regional values. We conclude that serious osteoporotic bone loss has a generalized nature, however, with a tendency towards lower values in the regions affected by fracture (viz: low bone mass in the legs of femoral neck fracture patients). Osteoarthritis may be associated with a high bone mass in most areas, but low values in the affected regions. Local lumbar spine measurement of bone mass by DPA is not superior to local forearm measurement of bone mass by SPA in predicting the nature of overall osteoporotic or osteoarthritic bone change.

Effects of gonadotrophin-releasing hormone agonist on uterine fibroids and bone density

Bone density (BD) was evaluated by single photon absorptiometry (SPA) in 18 women treated with Buserelin a gonadotrophin-releasing hormone (LHRH) analogue, for uterine fibroids. Buserelin was administered for a period of 6 mth. Amenorrhoea and oestradiol levels in the follicular-phase range were recorded in all patients during treatment. Fibroid volume was evaluated by means of ultrasound. SPA was performed at the 1/3 proximal radius and at the 1/10 distal radius sites before starting therapy and every 2 mth subsequently for 12 mth. BD was also measured in a control group of 18 normally-menstruating premenopausal women, matched for age and body mass index. No significant changes in BD at the proximal or distal radius sites were observed in either the cases or the controls during the study. Moreover, comparison of the data on the cases and the controls revealed no differences in BD at 0, 6 or 12 mth. Thus, although LHRH analogue treatment proved effective in reducing fibroids, it did not cause any significant changes in BD.

Differential effect of long-term oestrogen therapy on trabecular and cortical bone

The effect of long-term oestrogen therapy has been assessed in 40 oophorectomised women. Twenty-one of the women had received mestranol (mean 26 micrograms/day) and 19 received placebo tablets for a mean duration of 14 yr. A newly developed gamma-ray computed tomography (CT) scanner was used to measure trabecular and cortical bone separately in the distal radius. Bone density in the lumbar spine was measured using dual photon absorptiometry (DPA). Prevention against bone loss was demonstrated at all sites for the mestranol treated group (P less than 0.01). The deficit of radial trabecular bone (27%) was greater than that for radical cortical bone (14%). The deficit for the spine was intermediate (20%). One-year follow-up radial measurements showed a significant 1.2% increase (P less than 0.01) in cortical bone for the treated group. The DPA measurement was found to be best correlated (r = 0.80) with a mixed trabecular and cortical bone parameter in the radius. We conclude that the degree of bone loss at any site is dependent on the proportion of trabecular bone present.

New methods for identifying "at risk" patients for osteoporosis

Bone loss was determined in 178 women in the early postmenopausal period by photon absorptiometry measurement of forearm bone mineral content (BMC) every three months for two years. With a sequential cut-off technique, the results of a single determination of body fat mass, urinary calcium and hydroxyproline, and serum alkaline phosphatase, carried out at the first examination, correctly identified 79% of "fast bone losers" (bone loss greater than 3% annually) and 78% of "slow bone losers". The simple biochemical screening procedure was hereafter tested in a new group of 70 early postmenopausal women, who were followed for two years with measurement of local and total BMC. With this simple approach the majority of women at highest risk of osteoporotic fractures in later life can be identified in the early postmenopausal period and can be started on prophylactic hormone replacement therapy.

A cross-sectional study of age-related loss of mineral content of phalangeal bone in men and women

The bone mineral content of the second phalanx of the second digit was studied by quantitative microdensitometry. It is concluded that age-dependent loss of bone is a generalised phenomenon in men and women that occurs at different rates at different ages. In women, an accelerated rate of bone loss is observed between 50 and 57 years of age; in men such an acceleration is observed after 68 years of age. It appears that in a selected "ideal" population (with no disease or medication that may influence bone metabolism) the rate of bone mineral loss in women of 50-57 years of age is greater than in an unselected normal population. Furthermore, especially in the 50-57 years age group, the rate of loss at the mid-shaft of the phalanx in women is higher than at a site 25% from the proximal end. In men the rate of bone mineral loss at the 25% site exceeds that at midshaft, especially in the 68-75 year age group.

Reversal of postmenopausal vertebral bone loss by oestrogen and progestogen: a double blind placebo controlled study

Because of uncertainty about the place of hormones in the treatment of postmenopausal bone loss vertebral and forearm bone loss was measured by absorptiometry in early postmenopausal women before and after continuous or sequential treatment with combined oestrogen and progestogen in a double blind placebo controlled trial. Treatment with hormones significantly reversed the vertebral bone loss. The net gain in vertebral bone density amounted to 6.4% a year with continuous supplementation and 5.4% a year with sequential supplementation; the net gain in forearm bone density was lower (3.6% with continuous and 3.7% with sequential supplementation). Before a policy of supplementation with hormones can be recommended to all postmenopausal women with the aim of reducing the incidence of vertebral crush fractures further studies with different doses and combinations of hormones, administered over several years, are needed.

Measurement of spinal or peripheral bone mass to estimate early postmenopausal bone loss?

This report presents data from 153 healthy, early postmenopausal women who were randomly allocated to two years of treatment with estrogen or placebo. Bone mineral content in the forearms was measured by single-photon absorptiometry, and bone mineral density of the lumbar spine and total-body bone mineral by dual-photon absorptiometry, before and after one and two years of treatment. At the end of the two years, there were highly significant differences of 6 to 7 percent between the estrogen and the placebo groups at all sites measured. The range of the changes of the spine measurement was twice that of the forearm and total-body measurements. It is concluded that measurement of the forearm by single-photon absorptiometry is superior to measurement of the spine by dual-photon absorptiometry both in clinical studies and in the individual patient for detecting estrogen-dependent bone loss and its treatment by estrogen replacement.

GnRH agonists and antagonists. Current clinical status

Gonadotrophin-releasing hormone (GnRH) analogues offer a novel approach for the non-steroidal manipulation of the reproductive endocrine axis. GnRH agonists are now effectively employed in the management of precocious puberty, prostate and breast cancer, endometriosis, uterine leiomyoma, polycystic ovarian disease, and various other disorders. Unfortunately, contraceptive applications of GnRH agonists have been disappointing. The availability of slow release depot formulations of GnRH agonists, and the development of GnRH antagonists may further optimise and extend the clinical application of these compounds.

Total bone calcium in normal women: effect of age and menopause status

Bone density in different regions of the skeleton was measured in 392 normal women aged 20-80 years by dual photon absorpiometry. In premenopausal women, aged 25-50 years, multiple regression analysis of regional bone density on age, height, and weight showed a small significant decrease in total bone density (less than 0.01) but no significant change in other regions of the skeleton. In postmenopausal women there were highly significant decreases in all regions of the skeleton (p less than 0.001), and bone density in these areas decreased as a logarithmic function of years since menopause. Based on multiple regression analyses, the decrease in spine density and total bone calcium was 2.5-3.0 times greater in the 25 years after menopause than the 25 years before menopause. The largest change, however, occurred in the first five years after menopause. During this time the estimated annual change in spine density and total bone calcium was about 10 times greater than that in the premenopausal period. These results demonstrate the important effect of the menopause in determining bone mass in later life.

Postoophorectomy bone loss is associated with reduced bone Gla protein serum levels: a possible effect of osteoblastic insufficiency

To further investigate the relationship between oophorectomy (OF) and mineral bone loss, 15 women who underwent total hysterectomy and bilateral oophorectomy were studied for 12 months after surgery. Mineralometric and metabolic data were obtained before and after 3, 6, and 12 months. The women lost bone mineral content (measured by single photon absorptiometry) at the same rate they lost cortical and trabecular bone, suggesting that bone loss after OF is a generalized phenomenon. Our data also show that an increase in bone resorption takes place only in the first period after OF; the persistency of a negative bone balance up to 12 months, accompanied by a reduction of osteocalcin serum levels, may be dependent on a reduced bone formation, probably due to osteoblastic insufficiency.

Sex steroids and bone mass. A study of changes about the time of menopause

To examine the relationships between bone loss and sex steroids, 84 peri- and postmenopausal women were studied at 4-mo intervals for 3 yr. At each visit, measurements were made of bone mass at the midshaft and distal radius, of steroids, of gonadotropins, and of bone gla protein (BGP). Bone loss was approximately 1% per yr among late perimenopausal and postmenopausal groups, whereas the early perimenopausal group lost no bone. Mean serum estrogen and BGP concentrations predicted rates of bone loss. BGP was negatively correlated with the rate of bone loss (r = -0.45) and with mean estrogen concentrations (r = -0.40). Multivariate regressions showed estrogen concentrations to be strong independent predictors of the slope of bone mass over time. When BGP concentrations were added to the models, the significance of estrogen was reduced, suggesting that a portion of the estrogen effect was mediated through effects on rates of bone remodelling.

Prediction of rapid bone loss in postmenopausal women

Bone loss was determined in 178 women in the early postmenopausal period by photon absorptiometry measurement of forearm bone mineral content (BMC) every 3 months for 2 years. With a sequential cut-off technique, the results of a single determination of body fat mass, urinary calcium and hydroxyproline, and serum alkaline phosphatase, carried out at the first examination, correctly identified 79% of "fast bone losers" (bone loss greater than 3% annually) and 78% of "slow bone losers". With this simple approach the majority of women at highest risk of osteoporotic fractures in later life can be identified in the early postmenopausal period and started on prophylactic hormone replacement therapy.

Monitoring fluoride therapy in osteoporosis by dual photon absorptiometry

Dual photon absorptiometry (DPA) was used to evaluate changes in bone mineral mass in 108 osteopenic patients. Ninety were treated with fluoride and 18 served as controls. All osteopenic patients and 9 of the controls took calcium and vitamin D supplements. In 16 women estrogens were combined with the fluoride therapy. Seven patients received prednisone. Significant positive changes in bone mineral mass in the lumbar spine could be demonstrated over a mean observation time of 14-15 months in all groups treated with fluoride but not in the control group. The average increase in bone mineral mass in the lumbar spine (L2, L3 and L4 combined) ranged from 3.57% +/- 1.42% (sem, p less than 0.05) in women on fluoride to 10.36% +/- 3.17% (p less than 0.01) in men and 10.18% +/- 2.39% (p less than 0.001) in women on estrogen and fluoride. Changes in bone mineral mass in femoral necks (left and right combined) and femoral diaphysis were not significant. In the control group no significant changes were observed (lumbar spine: -1.68% +/- 1.75%, femoral necks -0.09% +/- 3.3% and femoral diaphysis -2.32% +/- 2.40%). It is concluded that a positive effect of fluoride on trabecular bone in the spine can be demonstrated with DPA on a group basis when data processing is done in a uniform way by a single observer. Its longitudinal use in individual patients necessitates a series of measurements to overcome the analytical error.