Change in bone mass immediately before menopause

Menopause is associated with bone loss, particularly at the distal radius, in black South African women: Findings from the Study of Women Entering and in Endocrine Transition (SWEET)

Menopause transition is associated with accelerated bone loss, though data are limited from sub-Saharan African (SSA). Our objective was to describe bone density, geometry and estimated strength in women by menopause status and to explore whether patterns differed within those living with HIV.

METHODS

Radius and tibia peripheral QCT data were collected for Black South African women (n = 430) aged 40-61 years with verified menopause and HIV status. pQCT outcomes were distal 4 % radius and tibia total cross-sectional area (CSA), total volumetric bone mineral density (vBMD), and compressive bone strength (BSIc); proximal 66 % radius and 38 % tibia cortical vBMD, total CSA, cortical thickness, and Stress-strain Index (SSI). Linear regression assessed associations between pre, peri-, and postmenopausal groups and pQCT outcomes adjusting for age, height, and weight, and then stratified by HIV status. Mean [95%CI] and tests for trend (p-trend) across menopausal groups are presented.

RESULTS

Women were mean (SD) age 49.2 (5.3) years, with a body mass index (BMI) of 32.4 (6.3) m/kg², and 18 % were living with HIV. After adjustment, later menopause stage was associated with lower 4 % radius total mean [95%CIs] vBMD (premenopause: 345.7 [335.8,355.5] vs. postmenopause: 330.1 [322.7,337.6] mg/cm³, p-trend = 0.017) and BSIc (premenopause: 0.39 [0.37,0.41] vs. postmenopause: 0.36 [0.35,0.37] g²/cm⁴; p-trend = 0.012). Similar trends were observed at the 66 % radius for cortical vBMD (premenopause: 1146.8 [1138.9,1154.6] vs. postmenopause: 1136.1 [1130.1,1142.0] mg/cm³; p-trend = 0.028) and cortical thickness (premenopause: 2.01 [1.95,2.06] vs. postmenopause: 1.93 [1.89,1.98] mm; p-trend = 0.036). After stratification by HIV status a similar patten was observed in women with HIV (cortical vBMD premenopause: 1152.9 [1128.5,1177.2] mg/cm³ vs. postmenopause: 1123.6 [1106.0,1141.2] mg/cm³, p-trend = 0.048). Total CSA varied little by menopause or HIV status at either radius sites; few differences were found at the tibia.

CONCLUSION

In black South African women, menopause is associated with lower bone density and strength at the distal radius, a common site of osteoporotic fracture, in addition to lower cortical density and thickness at the proximal radius. Although the sample size was small, following stratification by HIV, women living with HIV had evidence of lower cortical density across menopause stages, unlike those without HIV. These findings raise concern for the incidence of Colles' fractures in postmenopausal women in South Africa; longitudinal studies of fracture incidence and implications of living with HIV are required.

The cervical spine demonstrates less postoperative bone loss than the lumbar spine

The objective of this study is to determine the bone mineral density (BMD) changes in adjacent vertebra following anterior cervical discectomy and fusion (ACDF). Consecutive patients undergoing ACDF with available preoperative and postoperative computed tomography (CT) imaging were included. Quantitative CT measurements of screw-free cervical and first thoracic vertebra were performed. Comparisons between pre- and postoperative BMD in the vertebrae one or two levels above the upper instrumented vertebra (UIV + 1, UIV + 2) and one level below the lowest instrumented vertebra (LIV + 1) were assessed. Seventy-two patients (men, 66.7%) met the inclusion criteria. The patient population was 91.7% Caucasian with a mean age of 55.0 years. The mean interval (±SD) between surgery and secondary CT was 157 ± 23 days. Preoperative BMD (±SD) in UIV + 1 was 300.6 ± 66.2 mg/cm³ . There was a significant BMD loss of 1.5% at UIV + 1 after surgery, resulting in a postoperative BMD of 296.2 ± 64.8 mg/cm³ (p = .029). At UIV + 2 and LIV + 1, no significant differences between pre- and postoperative BMD (304.7 ± 75.7 mg/cm³ vs. 299.8 ± 74.3 mg/cm³ , 197.3 ± 50.4 mg/cm³ vs. 200.8 ± 48.7 mg/cm³ , p = .113 and p = .078, respectively) were observed. Clinical significance Our results demonstrate a small BMD decrease of 1.5% at UIV + 1. This suggests that the effect of ACDF surgery on the adjacent levels might be smaller compared to the previously described lumbar BMD loss of 10%-20% following posterior lumbar fusion procedures.

Changes in Bone Mineral Density and Trabecular Bone Score over Time between Vegetarian and Non-Vegetarian Middle-Aged and Older Women: A Three-Year Retrospective Medical Record Review

The effect of a vegetarian diet on bone health remains controversial. This retrospective medical record review compared changes in bone mineral density (BMD) and trabecular bone score (TBS) between vegetarian and non-vegetarian middle-aged and older women who underwent two general health examinations (T1 and T2) that were approximately three years apart. Generalized estimating equations were used to compare the change in lumbar spine and bilateral hip BMD and TBS over time. At T1, the mean age of the patients was 56.6 years (standard deviation 9.7 years) and the mean interval between T1 and T2 was 2.7 years. For women aged 40–55 years, compared with non-vegetarians, vegetarians were significantly associated with a larger reduction in lumbar spine BMD (p < 0.001) and left hip femoral neck BMD (p = 0.015) over the three-year interval. On the contrary, changes in BMD were not significant at any site in women aged ≥ 56 years. Moreover, the changes in BMD and TBS over the three-year interval did not significantly differ between vegetarian and non-vegetarian women aged 65–90 years. In conclusion, for women aged 40–55 years, vegetarian diets reduced bone quantity, as measured by BMD, but not bone quality, as measured by TBS.

Follicle-stimulating hormone and blood lead levels with bone mineral density and the risk of fractures in pre- and postmenopausal women

BACKGROUND

The conclusions on the associations of serum follicle-stimulating hormone (FSH) and blood lead levels with bone mineral density (BMD) were controversial. Furthermore, little was known on the impacts of co-existence of serum FSH and blood lead levels on BMD and the risk of fractures in premenopausal and postmenopausal women. Therefore, the present study aimed to examine the associations of serum FSH and blood lead levels with BMD and the risk of fractures in premenopausal and postmenopausal women.

METHODS

Data were derived from the National Health and Nutrition Examination Survey. FSH is assayed using the Microparticle Enzyme Immunoassay technology. Blood lead levels were measured using atomic absorption spectrometry. BMD was measured using dual energy X-ray absorptiometry. Fractures were defined as subjects with fractures in any site of hip, wrist, and spine.

RESULTS

This study included 3798 participants. Elevated blood lead levels were associated with increased serum FSH levels (β= 48.22, 95% CI: 40.21~ 56.22). Serum FSH levels were negatively associated with total femur BMD in pre- and postmenopausal women. However, elevated serum FSH levels were associated with a lower lumbar spine BMD and a higher risk of fractures only in postmenopausal women (β= -0.0010, 95% CI: -0.0015~ -0.0006; OR: 1.007, 95% CI: 1.000~1.014, respectively).

CONCLUSIONS

Serum lead levels were associated with serum FSH levels. Serum FSH levels were associated with a lower BMD and a higher risk of fractures.

Trabecular Bone Score Declines During the Menopause Transition: The Study of Women's Health Across the Nation (SWAN)

CONTEXT

Rapid bone density loss starts during the menopause transition (MT). Whether other components of bone strength deteriorate before the final menstrual period (FMP) remains uncertain.

OBJECTIVE

To discern whether trabecular bone score (TBS) declines during the MT.

DESIGN

An 18-year longitudinal analysis from the Study of Women's Health Across Nation.

SETTING

Community-based cohort.

PARTICIPANTS

A total of 243 black, 164 Japanese, and 298 white, initially pre- or early perimenopausal women, who experienced their FMP.

MAIN OUTCOME MEASURES

TBS, an indicator of bone strength.

RESULTS

Multivariable mixed effects regressions fitted piecewise linear models to repeated measures of TBS as a function of time before or after the FMP; covariates were age at FMP, race/ethnicity, and body mass index. Prior to 1.5 years before the FMP, in the referent individual (a white woman with age at FMP of 52.2 years and body mass index of 28.0 kg/m2), TBS evidenced no change (slope 0.12% per year, P = 0.2991). TBS loss began 1.5 years before the FMP, declining by 1.16% annually (P < 0.0001). Starting 2 years after the FMP, annual rate of TBS loss lessened to 0.89% (P < 0.0001). In the 5 years before through the 5 years after the FMP, in the referent individual, total TBS decline was 6.3% (P < 0.0001), but black participants' total TBS loss was 4.90% (P = 0.0008, difference in black and white 10-year change). Results for Japanese did not differ from those of white women.

CONCLUSIONS

The occurrence of an MT-related decline in TBS supports the thesis that this period is particularly damaging to skeletal integrity.

The menopause transition and women's health at midlife: a progress report from the Study of Women's Health Across the Nation (SWAN)

OBJECTIVE

Our initial understanding of the menopause transition (MT) has been framed by clinical samples of women seeking treatment rather than by population-based studies. The Study of Women's Health Across the Nation (SWAN) initiated in 1996 with an overall goal to define the MT, to characterize its biological and psychosocial antecedents and sequelae in an ethnically and racially diverse sample of midlife women.

METHODS

This review summarizes the central findings of SWAN to date that can inform women and their healthcare providers about the impact of the MT and midlife aging on overall health and well-being.

RESULTS

SWAN characterized changes in reproductive axis and menstrual cycle patterns that informed the development of the reproductive aging staging system Staging of Reproductive Aging Workshop+10; MT-related symptoms and mental health (vasomotor symptoms, sleep complaints, psychological symptoms, cognitive performance, and urogenital and sexual health); and physiological systems and functions (cardiovascular and cardiometabolic health, bone health, physical function performance) that are influenced by the MT. SWAN demonstrated substantial interrelations among these changes and significant racial/ethnic differences in the rate and magnitude of change in multiple health indictors in midlife women. The findings point to midlife as a critical stage for adopting healthy behavior and preventive strategies.

CONCLUSIONS

Over the past 23 years, SWAN has advanced our understanding of the impact of the MT and midlife aging on health and well-being in women. SWAN will be instrumental to determine whether MT-related changes during midlife are related to unfavorable health and well-being in early old age.

Bone and the perimenopause

Loss of ovarian function has a profound impact on female skeletal health. Bone mineral density findings from the Study of Women's Health Across the Nation demonstrate an accelerated rate of bone loss during the menopausal transition. The greatest reduction occurs in the year before the final menstrual period and the first 2 years thereafter. Clinical management includes maintenance of adequate dietary calcium and vitamin D intake, attention to modifiable risk factors, and osteoporosis screening. Indications, benefits, and risks of pharmacologic osteoporosis therapy should be assessed individually; there are currently no established guidelines addressing the treatment and prevention of osteoporosis in perimenopausal women.

Bone loss during menopausal transition among southern Chinese women

OBJECTIVES

Estrogen deficiency during menopausal transition is associated with rapid bone loss. The purpose of this study was to examine the time of onset, the rate, and predictors of menopausal bone loss.

STUDY DESIGN

Prospective data were analyzed from 160 Chinese women between the ages of 45 to 55 years who participated in the Hong Kong Osteoporotic Study.

MAIN OUTCOME MEASURES

All participants were studied yearly for 4 years. Demographic information, menstrual status according to the Stages of Reproductive Aging Workshop (STRAW), and lifestyle habits were recorded as well as bone mineral density (BMD) measured every visit. Baseline follicular stimulating hormone, sex hormone binding globulin, parathyroid hormones, C-terminal telopeptides of type 1 collagen, estradiol and testosterone were also measured.

RESULTS

There was no significant bone loss at the spine, femoral neck and total hip in premenopausal women. Maximal bone loss occurred within the STRAW stage -2 and -1. Age at menopause, baseline age, body weight and FSH were independent predictors of bone loss. Subjects in the lowest quartile of baseline body weight (<50 kg) lost bone 2 times faster at spine compared with those in the highest quartile (>61 kg). Subjects in the highest quartile of baseline FSH (>40 IU/l) lost bone 1.3-2.3 times faster at all 3 sites compared with those in the lowest quartile (<5.8 IU/l).

CONCLUSION

Strategies to retard bone loss should be stressed to middle aged women, especially those with lean body built or with early menopause, to prevent osteoporosis later on in life.

Progesterone and bone: actions promoting bone health in women

Estradiol (E(2)) and progesterone (P(4)) collaborate within bone remodelling on resorption (E(2)) and formation (P(4)). We integrate evidence that P(4) may prevent and, with antiresorptives, treat women's osteoporosis. P(4) stimulates osteoblast differentiation in vitro. Menarche (E(2)) and onset of ovulation (P(4)) both contribute to peak BMD. Meta-analysis of 5 studies confirms that regularly cycling premenopausal women lose bone mineral density (BMD) related to subclinical ovulatory disturbances (SODs). Cyclic progestin prevents bone loss in healthy premenopausal women with amenorrhea or SOD. BMD loss is more rapid in perimenopause than postmenopause-decreased bone formation due to P(4) deficiency contributes. In 4 placebo-controlled RCTs, BMD loss is not prevented by P(4) in postmenopausal women with increased bone turnover. However, 5 studies of E(2)-MPA co-therapy show greater BMD increases versus E(2) alone. P(4) fracture data are lacking. P(4) prevents bone loss in pre- and possibly perimenopausal women; progesterone co-therapy with antiresorptives may increase bone formation and BMD.

Amount of bone loss in relation to time around the final menstrual period and follicle-stimulating hormone staging of the transmenopause

BACKGROUND AND OBJECTIVE

The objective of the study was to describe bone loss rates across the transmenopause related to FSH staging and the final menstrual period (FMP).

DESIGN AND SETTING

This was a population-based cohort of 629 women (baseline age 24-44 yr) with annual data points over 15 yr.

MEASUREMENTS

Measures were bone mineral density (BMD), FSH to define four FSH stages, and menstrual bleeding cessation to define the FMP. Bone loss rates were reported by obesity status.

RESULTS

Annualized rates of lumbar spine bone loss began in FSH stage 3, which occurs approximately 2 yr prior to the FMP (1.67%/yr); bone loss continued into FSH stage 4 (1.21%/yr). Mean spine BMD in FSH stage 4 was 6.4% less than spine BMD value in FSH stage 1. Annualized rates of femoral neck (FN) bone loss began in FSH stage 3 (0.55%/yr) and continued into FSH stage 4 (0.72%/yr). The FN difference between mean values in FSH stage 1 and FSH stage 4 was 5%. Annualized rates of spine bone loss in the 2 yr prior to the FMP were 1.7%/yr, 3.3%/yr in the 2 yr after the FMP, and 1.1%/yr in the 2- to 7-yr period after the FMP. Nonobese women had lower BMD levels and greater bone loss rates.

CONCLUSIONS

Spine and FN bone loss accelerates in FSH stage 3. Bone loss also began to accelerate 2 yr before the FMP with the greatest loss occurring in the 2 yr after the FMP. Bone loss rates in both spine and FN BMD were greater in nonobese women than obese women.

Change in bone mineral density and its determinants in pre- and perimenopausal Chinese women: the Hong Kong Perimenopausal Women Osteoporosis Study

This 30-month study investigating bone change and its determinants in 438 perimenopausal Chinese women revealed that the fastest bone loss occurred in women undergoing menopausal transition but maintenance of body weight and physical fitness were beneficial for bone health. Soy protein intake also seemed to exert a protective effect.

INTRODUCTION

This 30-month follow-up study aims to investigate change in bone mineral density and its determinants in Hong Kong Chinese perimenopausal women.

METHODS

Four hundred and thirty-eight women aged 45 to 55 years were recruited through random telephone dialing and primary care clinic. Bone mass, body composition, lifestyle measurements were obtained at baseline and at 9-, 18- and 30-month follow-ups. Univariate and stepwise multiple regression analyses were performed with the regression coefficients of BMD/C (derived from baseline and follow-up measurements) as the outcome variables. Menopausal status was classified as pre- or postmenopausal or transitional.

RESULTS

Menopausal status was the strongest determinant of bone changes. An annual bone loss of about 0.5% was observed among premenopausal, 2% to 2.5% among transitional, and about 1.5% in postmenopausal women. Multiple regression analyses, revealed that a positive regression slope of body weight was protective for follow-up bone loss at all sites. Number of pregnancy, soy protein intake and walking were protective for total body BMC. Higher baseline LM was also protective for neck of femur BMD.

CONCLUSION

Maintenance of body weight and physical fitness were observed to have a protective effect on for bone loss in Chinese perimenopausal women.

Bone mineral density changes during the menopause transition in a multiethnic cohort of women

CONTEXT

Rates of bone loss across the menopause transition and factors associated with variation in menopausal bone loss are poorly understood.

OBJECTIVE

Our objective was to assess rates of bone loss at each stage of the transition and examine major factors that modify those rates.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a longitudinal cohort study of 1902 African-American, Caucasian, Chinese, or Japanese women participating in The Study of Women's Health Across the Nation. Women were pre- or early perimenopausal at baseline.

OUTCOME MEASURE

We assessed bone mineral density (BMD) of the lumbar spine and total hip across a maximum of six annual visits.

RESULTS

There was little change in BMD during the pre- or early perimenopause. BMD declined substantially in the late perimenopause, with an average loss of 0.018 and 0.010 g/cm2.yr from the spine and hip, respectively (P<0.001 for both). In the postmenopause, rates of loss from the spine and hip were 0.022 and 0.013 g/cm2.yr, respectively (P<0.001 for both). During the late peri- and postmenopause, bone loss was approximately 35-55% slower in women in the top vs. the bottom tertile of body weight. Apparent ethnic differences in rates of spine bone loss were largely explained by differences in body weight.

CONCLUSIONS

Bone loss accelerates substantially in the late perimenopause and continues at a similar pace in the first postmenopausal years. Body weight is a major determinant of the rate of menopausal BMD loss, whereas ethnicity, per se, is not. Healthcare providers should consider this information when deciding when to screen women for osteoporosis.

Effect of raloxifene on bone mineral density in premenopausal women at increased risk of breast cancer

CONTEXT

Raloxifene is a promising breast cancer prevention agent in postmenopausal women at increased risk for breast cancer. The effects of raloxifene in premenopausal women are unknown.

OBJECTIVE

We evaluated the effect of raloxifene in premenopausal women at increased risk for breast cancer on bone mineral density (BMD).

DESIGN

This was a phase II clinical trial.

SETTING

This study was conducted at an academic medical center.

PARTICIPANTS

Thirty-seven premenopausal women at increased risk for breast cancer enrolled in the trial. Thirty subjects began treatment and 27 were evaluable.

INTERVENTION

Raloxifene (60 mg daily) and elemental calcium (500 mg daily) were given for 2 yr. Subjects were followed up off medications for 1 yr.

MAIN OUTCOME MEASURE

The primary end point was the intrasubject percent change in BMD at 1 yr measured by dual-energy x-ray absorptiometry.

RESULTS

The mean baseline lumbar spine density was 1.027 g/cm(2). Lumbar spine density decreased 2.3% at 1 yr (P < 0.00001) and 3.5% at 2 yr (P < .00001). Percent change from yr 2 to 3 was +1.4%. The mean baseline total hip bone density was 0.905 g/cm(2). Total hip density decreased 0.3% at 1 yr and 1.0% at 2 yr (P = 0.033). Percent change from yr 2 to 3 was +1.7%.

CONCLUSIONS

Raloxifene use is associated with a decrease in BMD in premenopausal women at increased risk for breast cancer. The clinical significance of this decrease is unknown and is attenuated with stopping raloxifene.

Heritability of changes in bone size and bone mass with age in premenopausal white sisters

Femoral neck area expands and BMD decreases in premenopausal women. We used longitudinal DXA measurements on 388 premenopausal white sisters to show significant heritability of the rates of change in femoral neck area, BMC, and BMD.

INTRODUCTION

Bone mass and structure are highly heritable. However, genetic effects on age-related changes in bone mass and structure in adults have been much less studied.

MATERIALS AND METHODS

DXA measurements were made on 388 healthy white premenopausal sisters from 178 families. Rates of change in femoral neck area, BMC, and BMD, as well as body weight, were calculated from two measurements made an average of 5.7 years apart. Mixed models were used to test whether bone changes were related to age or weight change. Variance components models were used to estimate the heritability of the rates of change. A method was proposed to correct for the underestimation of heritabilities caused by measurement errors of the rates of change.

RESULTS

Femoral neck area increased with age, whereas BMD decreased. All of the rates of change at the femoral neck were positively correlated with weight change, but the rates of femoral neck changes did not vary with age. Adjusted for weight change, change in femoral neck BMC became negative. Significant heritabilities (0.29-0.36) were detected for changes in femoral neck BMC, BMD, and area adjusted for weight changes. Correction for DXA measurement error in the rate estimates increased the heritability estimates (from 0.29-0.36 range to 0.37-0.64 range).

CONCLUSIONS

Rates of change are heritable for femoral neck area, BMC, and BMD in premenopausal white women.

Physical activity in the prevention and amelioration of osteoporosis in women : interaction of mechanical, hormonal and dietary factors

Osteoporosis is a serious health problem that diminishes quality of life and levies a financial burden on those who fear and experience bone fractures. Physical activity as a way to prevent osteoporosis is based on evidence that it can regulate bone maintenance and stimulate bone formation including the accumulation of mineral, in addition to strengthening muscles, improving balance, and thus reducing the overall risk of falls and fractures. Currently, our understanding of how to use exercise effectively in the prevention of osteoporosis is incomplete. It is uncertain whether exercise will help accumulate more overall peak bone mass during childhood, adolescence and young adulthood. Also, the consistent effectiveness of exercise to increase bone mass, or at least arrest the loss of bone mass after menopause, is also in question. Within this framework, section 1 introduces mechanical characteristics of bones to assist the reader in understanding their responses to physical activity. Section 2 reviews hormonal, nutritional and mechanical factors necessary for the growth of bones in length, width and mineral content that produce peak bone mass in the course of childhood and adolescence using a large sample of healthy Caucasian girls and female adolescents for reference. Effectiveness of exercise is evaluated throughout using absolute changes in bone with the underlying assumption that useful exercise should produce changes that approximate or exceed the absolute magnitude of bone parameters in a healthy reference population. Physical activity increases growth in width and mineral content of bones in girls and adolescent females, particularly when it is initiated before puberty, carried out in volumes and at intensities seen in athletes, and accompanied by adequate caloric and calcium intakes. Similar increases are seen in young women following the termination of statural growth in response to athletic training, but not to more limited levels of physical activity characteristic of longitudinal training studies. After 9-12 months of regular exercise, young adult women often show very small benefits to bone health, possibly because of large subject attrition rates, inadequate exercise intensity, duration or frequency, or because at this stage of life accumulation of bone mass may be at its natural peak. The important influence of hormones as well as dietary and specific nutrient abundance on bone growth and health are emphasised, and premature bone loss associated with dietary restriction and estradiol withdrawal in exercise-induced amenorrhoea is described. In section 3, the same assessment is applied to the effects of physical activity in postmenopausal women. Studies of postmenopausal women are presented from the perspective of limitations of the capacity of the skeleton to adapt to mechanical stress of exercise due to altered hormonal status and inadequate intake of specific nutrients. After menopause, effectiveness of exercise to increase bone mineral depends heavily on adequate availability of dietary calcium. Relatively infrequent evidence that physical activity prevents bone loss or increases bone mineral after menopause may be a consequence of inadequate calcium availability or low intensity of exercise in training studies. Several studies with postmenopausal women show modest increases in bone mineral toward the norm seen in a healthy population in response to high-intensity training. Physical activities continue to stimulate increases in bone diameter throughout the lifespan. These exercise-stimulated increases in bone diameter diminish the risk of fractures by mechanically counteracting the thinning of bones and increases in bone porosity. Seven principles of bone adaptation to mechanical stress are reviewed in section 4 to suggest how exercise by human subjects could be made more effective. They posit that exercise should: (i) be dynamic, not static; (ii) exceed a threshold intensity; (iii) exceed a threshold strain frequency; (iv) be relatively brief but intermittent; (v) impose an unusual loading pattern on the bones; (vi) be supported by unlimited nutrient energy; and (vii) include adequate calcium and cholecalciferol (vitamin D3) availability.

Timing of follow-up densitometry in hormone replacement therapy users for optimal osteoporosis prevention

The objectives of the study were (1) to determine the time interval for repeat dual-energy X-ray absorptiometry (DXA) to detect significant bone loss, i.e., greater than the coefficient of variation (CV) of the center (2.8 x CV%) and (2) to assess how long hormone replacement therapy can be maintained to avoid undetected development of low bone mass and to not unduly delay appropriate treatment. A total of 3,826 healthy women, aged 40-65 years, participated in a prospective cohort study, 807 of whom were treated with transdermal estrogen replacement therapy and 626 with transdermal estrogen/progesterone regimens. The untreated group included the remaining 2,393 women. Between 1996 and 2002 they underwent a baseline DXA scan, and DXA scans were then repeated annually. There were no differences among the study groups at entry into the study. Treatment with estrogen was a protective factor for loss of bone mass at the lumbar spine (odds ratio [OR] =0.431, 95% confidence interval [CI] 0.344 to 0.522) and at the femoral neck (OR =0.433, 95% CI 0.352 to 0.521). Treatment with estrogen/progesterone also showed a protective effect against significant changes in follow-up BMD (>2.8 x 1.05% CV of densitometry at L1-L4, >2.8 x 2.3% CV at the femoral neck). In the treated group, significant differences in BMD at the lumbar spine (OR =1.593, 95% CI 1.423 to 2.355) did not appear within the first 3 years, and differences in BMD at the femoral neck (OR =3.555, 95% CI 2.782 to 4.905) did not appear within the first 4 years. It is concluded that in women aged 45-65 years, receiving transdermal hormone replacement therapy without risk factor for loss of bone mass, such as age < 55 years and body mass index <25 kg/m(2), periodical follow-up densitometries would not be necessary, provided that the duration of estrogen or estrogen/progesterone therapy is shorter than 3 years.

Bone densitometry in premenopausal women: synthesis and review

Bone loss prior to menopause is being increasingly identified in women. Clearly, low bone mineral density (BMD) is a significant risk factor for fracture in the estrogen-deficient female postmenopause. The significance of low bone density prior to menopause needs to be addressed. Low bone density in the premenopausal female may reflect attainment of a lower peak bone mass. It may also be secondary to progressive bone loss following achievement of peak bone density. The etiology of low bone density in the premenopausal female needs to be clarified with meticulous exclusion of secondary causes of bone loss. Menstrual status is an important determinant of peak bone mass as well as the development of bone loss in women prior to the onset of menopause. Subclinical decreases in circulating gonadal steroids may be associated with a lower peak bone mass as well as progressive bone loss in otherwise reproductively normal women. Elevations of follicle-stimulating hormone (FSH) of greater than 20 miu/L are associated with evidence of increased bone turnover marker activity and correlate with progressive bone loss in perimenopausal women. This transitional period requires further study with respect to the magnitude of bone loss experienced and the potential benefits of antiresorptive therapy. Detailed assessment of menstrual status is necessary in the evaluation of low bone density in premenopausal women. The majority of the cross-sectional and longitudinal studies completed evaluating BMD in the premenopausal years suggest that minimal bone loss does occur prior to menopause after attainment of peak bone mass. The magnitude of premenopausal bone loss, however, is controversial and may be site-dependent. More rapid rates of bone loss are seen in the transitional period beginning 2-3 yr prior to the onset of menopause. Prospective data are needed to understand further the relationship between BMD and fracture in the premenopausal period. Women with steroid-induced bone loss as well as other secondary causes of osteoporosis respond to antiresorptive therapy with documented improvements in BMD. Biomarkers can identify perimenopausal women with increased bone turnover. Lifestyle modification can improve BMD in the pre- and the perimenopausal period. Antiresorptive therapy has not been evaluated in pre- or perimenopausal women with low BMD in the absence of secondary causes of osteoporosis. As new treatment options are evaluated and become available, biomarker assessment may be of value in identifying women at risk of fracture.

Endogenous hormones and bone turnover markers in pre- and perimenopausal women: SWAN

We tested the hypothesis that higher serum osteocalcin and urinary N-telopeptide of type I collagen (NTx) concentrations would be found in women with increasing cycle irregularity or increased follicle stimulating hormone concentrations. We studied 2,375 pre- and early perimenopausal women from the Study of Women's Health Across the Nation (SWAN), aged 42-52 years, who self-identified their race/ethnic origin as African-American (28.3%), Caucasian (49.4%), Japanese (10.5%) or Chinese (11.8%). Outcome measures were serum osteocalcin, a measure of bone formation, and NTx, a measure of bone resorption. The explanatory variables were menopausal status, based on self-reported regularity of menstrual bleeding, and circulating endogenous hormone concentrations including estradiol (E(2)), testosterone (T), sex hormone binding globulin (SHBG) and follicle stimulating hormone (FSH) concentrations. Additionally, we evaluated the association of the bone turnover markers with the Free Androgen Index (FAI) and the Free Estradiol Index (FEI), ratios of total testosterone and estradiol concentrations to SHBG, respectively. Higher FSH concentrations were associated with higher NTx concentrations ( beta=0.003, partial r2=2.1%, p<0.0001), both before and after adjusting for other covariates (total explained variability of 9%). Higher FSH concentrations were also associated with higher osteocalcin concentrations ( beta=-0.216, partial r2=4.1%, p<0.0001, total explained variability of 15.4%). There were no significant associations of the bone turnover markers with other endogenous hormones, following adjustment for covariates. Mean osteocalcin and NTx values were not significantly different in premenopausal women compared to early perimenopausal women. In these pre- and early perimenopausal women, higher FSH concentrations, but not other serum reproductive hormone concentrations, are positively associated with greater bone turnover prior to the last menstrual period.

[Survey of bone mineral density in residents of selected areas of Hiroshima prefecture: effects of age and constitution on bone mineral density]

Because the complications of decreased bone mineral density, such as femoral neck fractures and severe spinal deformities, have a strong impact on daily life, prevention has become more important than therapy. The present study included as subjects 771 women residing in Innoshima City, Sera-gun, and Mihara City, all in Hiroshima Prefecture. We determined bone mineral density in the lumbar spine and femoral neck of these women, measured their height and weight, and examined the effect of age and body mass index (BMI) on bone density rate (YAM%). The subjects of the study were all volunteers. As no significant difference could be demonstrated in comparison with the results of the 1998 National Nutrition Survey of height, body weight, and BMI, we considered there would be no problem in extrapolating the results of the present determinations to middle-aged and elderly women. In the relationship between age and YAM%, a negative trend was observed prior to menopause, but was not significant. After menopause, however, a significant negative correlation was demonstrated. In addition, a significant positive correlation was observed between BMI and age-corrected YAM% for the lumbar spine and femoral neck. In future studies, the YAM% of the lumbar spine and femoral neck corrected for age and BMI should be investigated to determine the influence of lifestyle.

Bone loss at the femoral neck in premenopausal white women: effects of weight change and sex-hormone levels

To investigate whether bone loss occurs in the premenopause, we measured the bone mineral content (BMC), bone mineral density (BMD), and bone area in the spine (L2-L4), femoral neck, and total hip, as well as the sex hormone levels of 130 healthy premenopausal white women (age, 31-50 yr) at least three times over 1-9 yr. We found an increase in all three bone measurements at the spine but no change in volumetric density. Neither could we detect any age-related changes in any of the three measurements in the total hip. In contrast, we detected a significant decrease in femoral neck BMD over time, due to a decrease in BMC and increase in bone area. Greater loss in femoral neck BMD was associated independently with weight loss and lower levels of estrone sulfate or E2. Separating the women into those with FSH spikes (>20 IU/liter) and women with consistently low FSH, we found the latter group had smaller decrease in BMD and that the decrease was due less to a decline in BMC and more to an increase in bone area. In summary, femoral neck BMD decreases in premenopausal women, particularly those with lower levels of estrogens resulting from slowing ovarian function despite regular menses. This decrease can be offset by more rapid weight gain.

Hormone replacement therapy for bone protection in multiparous women: when to initiate it

OBJECTIVE

Hormone replacement therapy is used in postmenopausal women to improve symptoms of menopause and to protect bone and the cardiovascular system. We have evaluated the effects of parity in terms of number of deliveries on bone density and fracture risk at different ages.

STUDY DESIGN

We evaluated 1875 Hispanic women > or =50 years old (61.3 +/- 8.3 years), 425 with a history of nonselective fractures and 1450 without previous fractures. Body mass index was 27.3 +/- 4.3 kg/m(2). Bone mineral densities were determined for the total body in 1468 cases, the femur in 221 cases, and the lumbar spine in 189 cases. Women were classified according to lifetime number of deliveries (from 0 to > or =5), and bone mineral densities and odds ratios for fracture risk were calculated relative to the number of deliveries.

RESULTS

Bone mineral densities in total body, pelvis, and legs and total calcium and total mineral contents increased (P <.001) with > or =2 deliveries among women 50 to 59 years old but not among those > or =70 years old. The prevalence of fractures was higher in nulliparous than in multiparous women at all ages. Fracture risk was lower in multiparous women at all age groups, including those > or =70 years old (odds ratio, 0.47; 95% confidence interval, 0.26-0.84; P <.006).

CONCLUSION

Bone mineral density increases with the number of deliveries until the age of 69 years. Fracture prevalence and fracture risk are lower among multiparous women even at older ages. These findings suggest that hormone replacement therapy can be delayed until 65 years of age for multiparous women but should be initiated at the beginning of menopause for nulliparous women.

Characterization of perimenopausal bone loss: a prospective study

This study characterized the change in bone mass, bone markers, pituitary/gonadal hormones, vitamin D, parathyroid hormone, and anthropometric variables in a cohort of healthy women as they passed through normal menopause. We recruited 75 women > 46 years old who had premenopausal estradiol (E2) and gonadotropin levels and regular menses. During 9.5 years of observation, 54 experienced normal menopause (PM group) and 21 remained estrogen replete (ER group). Before the beginning of the menopausal drop and after its completion, the slope of bone mass on time in the PM group was 0% for the spine, -0.61% per year for the total body, and -0.45 % per year for the femoral neck. Designating these losses as "age related," there were 0, 4.88, and 3.40% losses for spine, total body bone mineral (TBBM), and femoral neck, respectively, in the 8-year period for which the data were analyzed. Across menopause, we found a sigmoid pattern of bone loss in the PM group beginning about 2-3 years before the last menses and ending about 3-4 years after the last menses. The total estrogen-deprivation bone losses were 10.50, 7.73, and 5.30% for the spine, TBBM, and femoral neck, respectively. In the ER group, we found a 0, 0.59, and 0.93% per year loss in spine, TBBM, and femoral neck, respectively. Serum osteocalcin rose 77%, serum total alkaline phosphatase rose 34%, and urinary hydroxyproline/creatinine (Hypro/Cr) ratio rose 44% in the PM group, while remaining stable in the ER group. We conclude that menopausal bone loss is a composite of loss caused by estrogen deprivation and age per se for the hip and total body, but is caused by estrogen deprivation alone for the spine.

Lower peak bone mass and its decline

There is evidence that two-thirds of the risk of osteoporotic fracture can be predicted from the pre-menopausal bone mineral density. The frequency of osteoporosis in older women may be modifiable by implementing invention strategies in the pre- and peri-menopausal periods. Lower peak bone mineral density and bone loss can be identified in women with altered reproductive hormone or calciotrophic hormone concentrations, or selected lifestyle practices. Alterations in reproductive hormones may occur in adolescence (from an early age of pregnancy or the amenorrhoea of anorexia nervosa or exercise), in the pre-menopause (nulliparity, oophorectomy, early ovarian failure or marginal hormonal status) or in the peri-menopause. Alterations in calciotrophic hormone concentrations include corticosteroid therapy and breast cancer treatment. Lifestyle risk factors include the misuse of alcohol and possibly smoking, physical inactivity or an imbalance in dietary intake. Effective intervention currently consists of treating underlying conditions and monitoring high-risk groups.

Genetic determination of variation and covariation of peak bone mass at the hip and spine

The likelihood of low trauma fracture in the elderly is highly predictable by peak bone mass (PBM) at age approximately 25-50 yr. We estimated the magnitude of genetic determination of the variation and covariation of PBM of the spine and hip (adjusted by age, gender, and ethnicity) in 47 independent healthy full-sib pairs and 27 healthy mother-offspring pairs. For the spine and hip, the narrow-sense heritabilities (h(2)) (mean +/- SE) were 0.76 +/- 0.34 and 0.84 +/- 0.36, respectively, when estimated from full sibs, and 0.86 +/- 0.38 and 0.84 +/- 0.39, respectively, when estimated from parent-offspring. Some genetic loci underlying PBM variation at the hip and spine are the same or closely linked, as is reflected by the high genetic correlation of 0.95 +/- 0.05 between them when estimated from full sibs, and 0.57 +/- 0.27 when estimated from parent-offspring, respectively. Generally, common familial environmental effects shared by relatives may bias these estimates. However, these effects may be small, since our results reported herein and those in other earlier studies indicate that common familial environmental effects are probably negligible in causing similarity of bone mass among family members. The correlation of bone mass among randomly sampled couples living in the same household is small and nonsignificant as measured either by densitometry at the radius and ulna or by quantitative ultrasound at the patella. The problem of shared environmental effects notwithstanding, we conclude that much of the PBM variation and covariation at the hip and spine is determined genetically.

A comparison of radial peripheral quantitative computed tomography, calcaneal ultrasound, and axial dual energy X-ray absorptiometry measurements in women aged 45-55 yr

Perimenopausal bone loss is considered to affect trabecular bone preferentially. Peripheral quantitative computed tomography (pQCT) quantifies trabecular bone mineral density (BMD) independently at the ultradistal radius. This article examines differences in pQCT BMD between late premenopausal and early postmenopausal women, comparing the differences with calcaneal ultrasound and axial dual energy X-ray absorptiometry measurements. One hundred nineteen normal perimenopausal women aged 45-55 yr who attended a randomized osteoporosis screening program were stratified by menopausal status into premenopausal (PRE: n = 79) and postmenopausal (POST: n = 40) groups. All measurements were lower in the postmenopausal group with the exception of ultrasonic velocity (PRE vs POST: 1397 +/- 53.8 vs 1421 +/- 58.5 m/s, p = 0.037). Total (391.8 +/- 52.9 vs 366.3 +/- 68.6 g/cm(3), p = 0.013) and subcortical (533.6 +/- 59.4 vs 504.3 +/- 79.8 g/cm(3) p = 0.018), but not trabecular (187.5 +/- 38.8 vs 173.2 +/- 46.6 g/cm(3), p = 0. 098) or cortical (561 +/- 53.4 vs 551.2 +/- 66 g/cm(3), p = 0.174), pQCT BMD measurements were significantly lower in the POST group, as were ultrasonic attenuation (79.4 +/- 16 vs 72.3 +/- 18.0 dB/Mz, p = 0.034), DXA spine (1.032 +/-16 vs 0.959 +/- 0.2 g/cm(2), p = 0.003), and all hip (p </= 0.001) measurements. Although body mass index (BMI) was positively and menopausal status and age negatively correlated with most bone mass measurements, adjusting for BMI did not alter the relative deficits in postmenopausal compared with premenopausal women. This study suggests that early postmenopausal bone loss at the radius preferentially affects subcortical, rather than trabecular, bone in the appendicular skeleton, which suggests preferential trabecular bone loss in the axial skeleton.

Bone mineral density and its change in pre-and perimenopausal white women: the Michigan Bone Health Study

There is a need to better understand potential bone mineral density (BMD) loss during the menopausal transition since this period may include the initiation of interventions. The study purpose was to determine if there was BMD loss at the femoral neck, lumbar spine, or total body bone sites in a population-based study of women approaching or transitioning the midlife. The 583 enrollees were 25-45 years of age at the first of four annual measurements from 1992 through 1996. Bone mineral content and bone width were measured using dual-energy X-ray absorptiometry. Considering all enrollees collectively, there was a significant 3-year decline (1%) in BMD at the femoral neck over the 3-year period (p = 0.076). There was no significant annual change in the lumbar spine (p = 0.11), and a significant annual increase in the total body BMD (p = 0.0003). Within subgroups and cross-sectionally, BMD values of the femoral neck were 5% lower in women classified as perimenopausal compared with premenopausal enrollees; BMD was 3% and 1% lower at the lumbar spine and total body site, respectively. Longitudinally, among perimenopausal women, a double oophorectomy was associated with BMD loss in the spine (p = 0.0003), even though 75-85% of these women had a hormone replacement prescription at some time during the study period. In summary, the site with evidence of loss was the femoral neck, specifically among perimenopausal women. There was little evidence of substantial total body or lumbar spine BMD loss in premenopausal women with ovaries who maintained follicle-stimulating hormone levels < 20 mIU/l in the early follicular period. Double oophorectomy, even with hormone replacement, was associated with bone loss.

Postmenopausal hormone therapy into the 21st century

At the time of the menopause, a review of the major health issues can be especially rewarding. Besides the general issues of good health, particular attention is now being focused on prevention of cardiovascular disease and osteoporosis because of the potentially beneficial effects of postmenopausal hormone therapy. Hormone therapy should be offered to most women as they consider their paths for successful aging. However, as for any pharmacological intervention, the benefits of treatment must outweigh the risk. The available data would appear to indicate that, for most women, this is in fact the case with current research into future hormonal therapies aimed at further improving the benefit:risk ratio.

The menopause transition

New paradigms for the study of menopause will increase our understanding of whether symptoms, syndromes, and chronic diseases are associated with menopause. Rather than considering menopause as a discrete event, it has become clear that the menopause transition takes place over many years. Although this realization is central to our understanding of menopause, it is difficult to measure the temporal pattern of changes in hormones and their relation to concurrent or subsequent health-related events. The model of hormonal changes at the time of the transition has been expanded to include not only declines in estrogen but changes in a broader range of hormones, including the potential role of androgens. New models are attempting to account for the pattern and frequency of changes in hormone levels. Another level of complexity is contributed by the expansion of the menopause model to include comorbid medical and psychiatric conditions, environmental influences, and behaviors as covariates that influence the expression of menopause-related events. Although this more complicated paradigm makes the conduct of menopause research more challenging, it is also likely to elucidate previously confusing data, as the proper understanding of potentially complex exposures, effect modifiers, and confounders is more likely to provide clearer answers to critical research questions.

Apparent pre- and postmenopausal bone loss evaluated by DXA at different skeletal sites in women: the OFELY cohort

We measured the bone mineral density (BMD) at various skeletal sites (total body, hip, anteroposterior [AP] and lateral [lat] spine, and forearm) in a large population-based cohort of women aged 31-89 years (the OFELY cohort), and results were analyzed according to age and postmenopausal years. A significant apparent bone loss was found before the menopause in cancellous bone, i.e., at the lat spine and Ward's triangle (-10%; p < 0.05-0.001). Cross-sectional analysis indicated that, after the menopause, apparent bone loss was accelerated within the 10 years following menopause, continued thereafter at all sites except the AP spine, and was again accelerated in elderly menopausal for more than 25 years. Between 30 and 80 years, BMD decreased by 15 to 44% (T score -1.6 to -3.4) according to the site. The amount of apparent bone loss was highest at the Ward's triangle when expressed in percentage (44%) and at the mid- and distal radius when expressed in number of standard deviations from the peak bone mass (-3.4). As a result, the percentage of women classified as osteoporotic according to the World Heath Organization, i.e., with a T score < or = -2.5, varied substantially from site to site and was highest at the radius (37% and 46%) and lateral spine (25-31%), intermediate at the Ward's triangle, AP spine, and whole body BMD, and lowest at the whole body bone mineral content, femoral neck, and trochanter (10-12%). In conclusion, this cross-sectional but large study suggests that there is a moderate apparent premenopausal bone loss that occurs only at cancellous bone sites and that apparent bone loss is accelerated at most skeletal sites after the age of 75 years. Because of the highly variable coefficient of variation of the peak bone mass at various skeletal sites, the percentage of postmenopausal women identified as being osteoporotic varies widely according to the site of measurement.

Heterogeneity of trabecular and cortical postmenopausal bone loss: a longitudinal study with pQCT

Eighty-one women were studied longitudinally to measure trabecular bone mineral density (BMDTrab) and cortical bone mineral density (BMDCorti) in the distal radius by peripheral quantitative computed tomography (pQCT) at intervals of about 1 year and to calculate the rate of percent change/year. Fifty-three women were naturally postmenopausal [mean age 63.3 +/- 5.3 years, age at menopause 50.7 +/- 3.8 years, 13 years since menopause (YSM)] and 28 had been ovariectomized (mean age 52.7 +/- 5.8 years, age at menopause 39.5 +/- 5.0 years, 13 YSM). There was no difference between groups (ANOVA) in the rate of percent change/years in BMDTrab (p = 0.692), but there was in BMDCorti (p = 0.020). When the women who had either gained or lost bone mass were compared (chi-square test), only BMDCorti differed significantly (p = 0.018). Considering > -2.5% change/years as the limit for rapid bone mass loss, BMDTrab values showed that 43% of the naturally postmenopausal women and 42.7% of the ovariectomized women had rapid bone loss (p ns). On the basis of BMDCorti values, 45% of the naturally postmenopausal women and 28.4% of the ovariectomized women had rapid bone loss (p = 0.018). Height, weight, body mass index (BMI), age, YSM, and years of reproductive life did not differ (ANOVA) between the women who gained or lost either BMDTrab or BMDCorti. Using Fisher's r to z and partial correlation adjusted for age and YSM of the percent change/year in BMDTrab and BMDCorti in the overall group and in each menopausal group, only BMDCorti differed.

The use of etidronate and calcium versus calcium alone in the treatment of postmenopausal osteopenia: results of three years of treatment

The purpose of this open, prospective, controlled, randomized trial was to study the effect of intermittent, cyclic etidronate on the bone mass of osteoporotic postmenopausal women with or without fractures. Eligible subjects were asymptomatic women less than 75 years old who had been amenorrhoeic for at least 1 year. Those with secondary osteoporosis were excluded. Subjects also had to be ambulant with a bone mineral density (BMD) of the lumbar spine > 1 SD below that of age matched controls (Z-score < -1 SD). Eighty patients were enrolled, of whom 65 were recruited through a screening programme conducted in the practices of two general practitioners. The remaining patients were from other referrals. The subjects were randomized to two groups of 40 women. Treatment regimens were as follows. The etidronate group was treated with etidronate 400 mg once daily for 14 days followed by 76 days of 500 mg of elementary calcium once daily; this cycle was repeated every 3 months. The calcium group took 500 mg of elementary calcium once daily. The groups were not different in age, height, weight, time since menopause. BMD at baseline and prevalent vertebral fractures. In 50 patients (28 in the etidronate group and 22 in the calcium group) no vertebral fractures were present (67%). Sixty-four patients (35 in the etidronate group and 29 in the calcium group) completed the 3 years of the study. In the etidronate group the mean BMD of the lumbar spine, femoral neck, trochanter and Ward's triangle increased by 5.7%, 1.4%, 7.1% and 10.9% from baseline values respectively (p < 0.05 at all sites except for the femoral neck). In the calcium group no significant changes from baseline were found at any time point at any site after 3 years, except for the femoral neck, where BMD at 156 weeks decreased significantly by 3% (p < 0.003). In 3 patients, all in the calcium group, six new fractures were found. There were no serious adverse effects. We conclude that intermittent, cyclic treatment with etidronate causes a significant increase in the BMD of the lumbar spine and the proximal femur in osteopenic postmenopausal women, and that treatment is safe and has no serious adverse effects.

Age, menopause, bone turnover markers and lumbar bone loss in healthy Japanese women

The change in lumbar vertebral bone mineral density (BMD) during a 2-year study period was examined in 167 healthy middle-aged and elderly Japanese women with reference to age, menopausal status and bone turnover markers at baseline. The perimenopausal and postmenopausal groups of the subjects showed a significant loss of BMD during the study period but the premenopausal women did not. The annual percent decrease of BMD (delta BMD) in the perimenopausal women (-2.40% in average) was significantly greater than that in either of the premenopausal (-0.01%) or over-all postmenopausal women (-0.85%). The subjects who had been postmenopausal for less than 10 years showed a significant bone loss. delta BMD in the postmenopausal women became less marked as the postmenopausal duration increased. The bone loss was accelerated for about 10 years after menopause. The pattern and magnitude of bone loss of Japanese women seemed to be similar to those of Caucasian women. The regression equation for delta BMD based on the bone turnover markers at baseline was shown to be significant in the postmenopausal women and the serum level of bone-specific alkaline phosphatase isoenzyme had a significant relation to delta BMD. However, this equation accounted for only 17.3% of the total variance of delta BMD and, hence, its validity was not sufficiently high for the prediction of bone loss in clinical settings.

Exercise and reproductive factors as predictors of bone density among osteoporotic women in Mexico City

We examined the association between physical activity and reproductive factors with bone density among 313 Mexican women, aged 26-83 years. Bone mineral density (BMD) was measured with a HOLOGIC QRD 1000 w, DXA densitometer at the lumbar spine and femoral region. We explored the relation between BMD and parity, age, body mass index (BMI), type of menopause, and level of exercise. Multiple regression models examining determinants of bone density at the lumbar and femoral regions showed that increasing age and lack of exercise were statistically significant predictors of bone demineralization. The number of pregnancies also had a deletereous effect on bone density, especially for lumbar spine, as well as BMI <20 kg/m2. Our results suggest that physical activity, parity, and BMI are important determinants of bone density in this population.

Ovulatory premenopausal women lose cancellous spinal bone: a five year prospective study

Healthy premenopausal women with regular cycles are believed to be increasing or maintaining bone density. However, few studies have prospectively documented spinal cancellous bone, the bone that changes rapidly in response to reproductive hormones, in this population. Furthermore, our previous one-year study documented that 24% of the one-year bone change by quantitative computed tomography (QCT) was related to subclinical ovulatory disturbances (short luteal phase and non-ovulation) in the presence of regular menstrual cycles. The purpose of this study was to document the cancellous bone change over five years in this initially ovulatory, premenopausal cohort of 66 healthy women. Thirty-seven women, who continued to be premenopausal and have regular cycles, completed this five-year study. Those enrolled differed only by being older and weighing less than those who could not be contacted (n = 19) or who declined to participate (n = 10). Documentation of current ovulatory characteristics was obtained for at least three cycles in 27 women. At the five-year assessment, the volunteers were 40.6 (range 26-47) years old, weighed 58.5 (41-77) kg, and were 160.9 (149-174) cm in height. All were premenopausal, healthy, nonsmokers with regular menstrual cycles (mean 27.7, range 24-33 days). Six women with intervening events (such as pregnancy or use of oral contraceptives) had interval (12 to 60 months) QCT changes similar to the remaining 31 (-7.98 vs. -4.92 mg/cm, p = 0.1, respectively). Mean five-year QCT was 143.0 +/- 20.2 mg/cm, whereas the initial mean value was 151.9 +/- 20.1 mg/cm. Significant QCT loss over five years (-8.9 +/- 6.2 mg/cm) (95% Cl -6.9 to -11.0) correlated with QCT change in the first year (r = 0.629, p < 0.001). First-year change was not related to the subsequent four-year interval change (r = -0.056, p = 0.74), however. Five-year QCT change was not related to age, weight, osteoporosis family history, estimated calcium intake, or exercise, but did correlate with year one luteal index (luteal/cycle length) (r = 0.339, p = 0.043). Significant cancellous spinal bone loss occurs in healthy, ovulatory premenopausal women, and is influenced by subclinical disturbances of ovulation.

Effect of menopause on femoral and vertebral bone loss

The aim of this study was to investigate the effect of menopause on bone loss in the proximal femur and the lumbar spine. The rates of change in bone mineral density (BMD) were measured longitudinally by dual X-ray absorptiometry (DXA) at the femoral neck (FN), Ward's triangle (WT), and trochanter (TR) together with the lumbar spine in 81 healthy postmenopausal women (45-65 years of age) who had passed a natural menopause, 6 months to 12 years before. A significant correlation between the rate of change and interval since menopause was evidenced. The best fit of the data was a binomial function of interval since menopause at the spine, FN, and WT and a simple linear regression at TR level. At each skeletal site, the rate of bone loss (mean +/- SD) was significantly different (p<0.05) and twice as high in women who were between 6 months and 2 years postmenopausal at enrollment (FN, -1.82 +/- 1.1%; WT, -2.43 +/- 1.7%; TR, -1.12 +/- 1.7%) than in those who were beyond 5 years of menopause (FN, -0.48 +/- 0.8%; WT, -0.68 +/- 2.1% TR, 0.41 +/- 1.2%). A poor correlation (r = 0.39 - 0.42, p<0.001) was found between the rate of vertebral and that of femoral postmenopausal bone loss. This study demonstrates that menopause is associated with a rapid and transient bone loss in BMD of the proximal femur, which declines with time after 3 years. These data suggest that therapy should be initiated as early as possible after menopause to prevent bone loss.

Menopause-related changes in bone mineral density in Japanese women: a longitudinal study on lumbar spine and proximal femur

We investigated 2-year longitudinal changes of bone mineral density (BMD) in lumbar spine and proximal femur in 64 Japanese women aged 38-67. Forty subjects were premenopausal (mean age 44.9) and 24 postmenopausal (mean age 54.6) at enrollment of the study. Six subjects experienced menopause during the 2-year study period and were defined as the perimenopausal group. Measurements of BMD were performed using dual-energy X-ray absorptiometry at L2-4, femoral neck, greater trochanter, and Ward's triangle. Paired t test revealed no significant decrease in BMD at any site in the premenopausal group. Significant annual decrease in BMD was observed in the perimenopausal group at L2-4, femoral neck, and greater trochanter. A similar tendency was observed in Ward's triangle, but did not reach statistical significance. In the postmenopausal group, significant decrease in BMD was found at the proximal femur, but not at L2-4. Significant inverse correlation between age and change rate of BMD was found at L2-4, but not at the proximal femur, in premenopausal women. In postmenopausal women, there was a significant association between body weight (BW) change and change rate in BMD at L2-4, femoral neck, or greater trochanter. This association was not found in the premenopausal group. These results suggest that effect of menopause on BMD may be different in individuals and sites of the skeleton. BW change may affect change in BMD in postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)

Spinal bone mineral loss in estrogen-replete, calcium-replete premenopausal women

After peak bone mass in women is attained, the benefits of increased dietary calcium or supplemental calcium are uncertain. In a longitudinal, 4-year study we have investigated the effect of calcium intake on bone mineral in a group of 41 premenopausal women, aged 38-42 years at entry. Skeletal density was measured four times during the 4-year follow-up; spinal trabecular bone density (STBD) was measured by quantitative computed tomography, and midradius bone mineral density (RBMD) was measured by single photon absorptiometry. At baseline, no differences in bone density were observed among subjects in the highest and lowest quartiles of habitual dietary intake. Overall, STBD declined -0.86 +/- 0.15% per year (p < 0.001), but RBMD did not decline. Total calcium intake (dietary calcium plus supplemental calcium) did not correlate with the rate of STBD loss. Serum estradiol level did not decrease during the study, and bone loss did not correlate with the mean estradiol level. We conclude that premenopausal women in the fifth decade lose about 1% of spinal trabecular mineral yearly, in spite of a normal serum estradiol level and ample calcium intake.

Nafarelin therapy in endometriosis: long-term effects on bone mineral density

OBJECTIVE

The study intent was to examine long-term effects on bone mass of 3 or 6 months of nafarelin therapy for endometriosis.

STUDY DESIGN

Women with established endometriosis (N = 173) were randomized to receive nafarelin (200 micrograms intranasally twice a day) for either 3 or 6 months in a double-blind fashion. Bone mineral density was measured by dual energy x-ray absorptiometry at lumbar spine and proximal femoral sites for 18 months.

RESULTS

Bone mineral density declined at spinal and femoral sites similarly in both 3- and 6-month treatment groups. There was a partial, but incomplete, return to baseline levels after 12 to 15 months of follow-up. The recovery of bone mass was more complete in subjects with higher dietary calcium intakes.

CONCLUSION

Nafarelin therapy for endometriosis results in a sustained loss of spinal and femoral bone density, particularly in women with lower calcium intakes.

Impact of the menopause on skeletal metabolism and osteoporotic syndromes

Evidence is rapidly accumulating that implicates calcium intake and genetic factors as important determinants of the variations in bone mass in many geographical areas as well as the loss of bone following the accumulation of peak bone mass. However, it has also been well established that the postmenopausal component of bone loss is one of the predominant factors contributing to increases in the ratio of the female/male risk of skeletal fractures after the sixth decade of life, and that vertebral bone loss can result from relatively mild changes in estrogen production and metabolism before the clinical menopause begins. Although estrogen use during early menopause prevents bone loss in the axial and appendicular skeleton in the majority of females, those estrogen-dependent mechanism(s) that initiate and perpetuate alterations in osteoclast-osteoblast interactions and bone remodeling are still ill-defined. Until the specific pathophysiological mechanisms have been defined, the informed physician should attempt to identify those peri- and postmenopausal patients at risk for more active bone turnover and rapid bone loss syndromes utilizing well-established and FDA-approved therapeutic interventional procedures to prevent the loss of skeletal tissue.

Magnitude and determinants of premenopausal bone loss

Bone loss prior to menopause may contribute to a woman's risk for fracture due to osteoporosis later in life. Most, but not all, longitudinal and cross-sectional studies suggest that bone mass decreases prior to menopause. This bone loss may be prevented by calcium supplementation. Heredity, exercise and menstrual status also have an impact on bone mass. Prevention of bone loss prior to menopause will allow women to enter menopause with a greater bone mass reducing their risk of subsequent fracture.

Bone mass and ageing

Bone can be divided into two kinds of tissue, cortical and trabecular bone. The skeleton comprises approximately 80% cortical bone, mainly in peripheral bones, and 20% trabecular bone, mainly in the axial skeleton. Bone density increases with skeletal growth to a peak in late adolescence or early adulthood. Bone loss subsequently occurs with ageing in both sexes, and in females accelerated loss occurs at the menopause. The risk of osteoporotic fracture in later life is the result of peak bone mass achieved at skeletal maturity and subsequent age-related and postmenopausal bone loss. Peak bone mass is largely genetically determined but is also influenced by environmental factors such as dietary calcium and physical activity. Bone loss with ageing occurs at different rates and different times in different skeletal sites. Femoral neck bone loss probably occurs in a linear fashion throughout life from early adulthood but may be accelerated at the menopause. Spinal bone loss may commence before the menopause but is rapidly increased in the immediate postmenopausal years. Bone strength is directly related to bone density, but the loading force is also relevant to risk of fracture.

The effects of menopause on longitudinal bone loss from the spine

Two hundred and thirty women aged 45-66 years were divided into three groups according to their menopausal status and were followed to assess the changes in vertebral bone mineral density (BMD). These included 71 premenopausal, 42 perimenopausal, and 117 postmenopausal women. Menopausal status was assessed through menstrual history and plasma concentrations of 17 beta estradiol and luteinizing hormone. BMD was measured by dual photon absorptiometry between 2 and 5 times over an average period of 27 months, and annual rates of changes were calculated by linear regression. BMD decreased significantly (P < 0.0001) in the three groups during the follow-up. Mean (+/- SD) annual rate of change was -0.79 +/- 1.5% for premenopausal, -2.35 +/- 1.5% for perimenopausal, and -1.24 +/- 1.5% for postmenopausal women. There was no difference in the rates of bone loss between the perimenopausal group and the postmenopausal group within 3 years after menopause (1-2 years: -2.34 +/- 2.1%; 2-3 years: -1.9 +/- 1.5%). Thereafter, rates decreased exponentially with time since menopause to fall out at the same level as the premenopausal level. These longitudinal data indicate that vertebral bone loss begins before menopause and accelerates sharply during menopause to decline exponentially with time after 3 years.