Epidemiology of bone mass in premenopausal women

Dietary Calcium Intake and Osteoporosis Risk in Arab Adults

Osteoporosis is a major public health concern in Saudi Arabia's aging population. There is particularly limited information on how diet affects bone loss in this ethnic group. The purpose of this study was to examine the association between dietary calcium (Ca) intake and osteoporosis risk in Saudi adults. A total of 1950 patients (416 males and 1534 females) with known risk factors for osteoporosis participated in this cross-sectional study. A short questionnaire (CaQ) was used to assess dietary Ca intakes in patients attending tertiary hospitals in Riyadh City. The prevalence of osteoporosis was 21.3% and was more common in females (93.5%). Patients with osteoporosis were older (p < 0.001) and had lower BMI (p < 0.001). Results showed that the overall mean Ca intake was only 445.1 mg/day (recommended dietary intake of 1300 mg/day). Tea intake (OR = 0.8 95%CI: 0.7-1.0; p = 0.02) and consumption of fish and eggs (OR = 0.9 95%CI: 0.8-1.0; p = 0.01) were significantly associated with a lower risk of osteoporosis. Furthermore, consumption of biscuits, cake and bread slices were significantly associated with higher incidence of osteoporosis (OR = 1.3 95%CI: 1.0-1.5; p = 0.02). In conclusion, extremely low dietary Ca intake was observed among Saudi adults already at risk of osteoporosis. A balanced diet including high amount of Ca, vitamin D and omega-3 fatty acids accompanied by limiting consumption of foods high in saturated fats and glycemic index may be helpful in reducing osteoporosis risk in the Saudi adult population.

The Role of Soy Isoflavones in the Prevention of Bone Loss in Postmenopausal Women: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

The aim of the report was to determine the effects of soy isoflavones on lumbar spine, femoral neck, and total hip bone mineral density (BMD) in menopausal women. MEDLINE (PubMed), EMBASE, and Cochrane Library databases were searched for articles published in English during 1995–2019. Studies were identified and reviewed for inclusion and exclusion eligibility. Weighted mean differences (WMD) were calculated for each study and were pooled by using the random effects model. Eighteen randomized controlled trials were selected for meta-analysis. Different types of soy phytoestrogens, i.e., genistein extracts, soy isoflavones extracts, soy protein isolate, and foods containing diverse amounts of isoflavones were used in the studies. The analysis showed that daily intake of 106 (range, 40–300) mg of isoflavones for 6–24 months moderately but statistically significantly positively affects BMD, compared with controls: lumbar spine WMD = 1.63 (95% CI: 0.51 to 2.75)%, p = 0004; femoral neck WMD = 1.87 (95% CI: 0.14 to 3.60)%, p = 0.034; and total hip WMD = 0.39 (95% CI: 0.08 to 0.69)%, p = 0.013. Subgroups analyses indicated that the varying effects of isoflavones on BMD across the trials might be associated with intervention duration, racial diversity (Caucasian, Asian), time after menopause, form of supplements (especially genistein), and dose of isoflavones. Our review and meta-analysis suggest that soy isoflavones are effective in slowing down bone loss after menopause.

What is normal bone health? A bioarchaeological perspective on meaningful measures and interpretations of bone strength, loss, and aging

Bioarchaeological (the study of archeological human remains together with contextual and documentary evidence) offers a unique vantage point to examine variation in skeletal morphology related to influences such as activity, disease, and nutrition. The human skeleton is composed of a dynamic tissue that is forged by biocultural factors over the entire life course, providing a record of individual, and community history. Various aspects of adult bone health, particularly bone maintenance and loss and the associated skeletal disease osteoporosis, have been examined in numerous past populations. The anthropological study of bone loss has traditionally focused on the signature of postmenopausal aging, costs of reproduction, and fragility in females. The a priori expectation of normative sex-related bone loss/fragility in bioanthropological studies illustrates the wider gender-ideological bias that continues in research design and data analysis in the field. Contextualized data on bone maintenance and aging in the archeological record show that patterns of bone loss do not constitute predictable consequences of aging or biological sex. Instead, the critical examination of bioarchaeological data highlights the complex and changing processes that craft the human body over the life course, and calls for us to question the ideal or "normal" range of bone quantity and quality in the human skeleton, and to critically reflect on what measures are actually biologically and/or socially meaningful.

The effect of oral contraceptive different patterns of use on circulating IGF-1 and bone mineral density in healthy premenopausal women

Both insulin-like growth factor-1(IGF-1) and oral contraceptive (OC) use have been linked to premenopausal breast and colorectal cancers, osteoporosis and cardiovascular disease. Understanding the effects of different patterns of use of OC on IGF-1 levels and bone mineral density (BMD) may offer insight into its influence on osteoporosis. We conducted a cross-sectional study, which included 135 women, who were then divided into three groups: Group A who were OC current users, 41 women; Group B who never use OC, 51 women; and Group C who were past users of OC, 41 women. Each patient completed a questionnaire on demographic parameters, marital state history and contraception history including duration of use and type of contraceptive pills or used method. Lower-end radius, proximal femur and lumbar spine BMD were measured by dual-energy X-ray absorptiometry. IGF-1 was assessed with chemiluminescent immunometric assay. The three groups were similar in total body T value of BMD (with slight better results in past users than the other two groups but it was statistically insignificant difference), and past users showed significantly higher BMD values compared to current users at spine, femur and forearm. Nonusers also had better BMD values compared to current users (spine and forearm BMD). Among past users, the mean level of circulating IGF-1 was higher than the other two groups and that difference was statistically significant. Past OC use and/or nonuse has a more favorable impact on BMD compared to current use and that this relationship is in part mediated by IGF-1. Hence, it appears that OC use is beneficial to BMD if used in the past and then discontinued or if never used at all compared to current use.

Low bone mass in urban Indian women above 40 years of age: prevalence and risk factors

OBJECTIVE

To assess the prevalence and the relative importance of risk factors for low bone mass in Indian pre- and post-menopausal women.

METHODS

Data were collected on anthropometry and lifestyle factors in apparently healthy 80 pre- and 92 post-menopausal (40-75 years) women. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. Fasting blood samples were analysed for Parathyroid hormone, vitamin D, calcium and zinc.

RESULTS

BMD at all three sites was significantly lower in post-menopausal than the pre-menopausal women (p < 0.001). Prevalence of osteoporosis was highest at the lumbar spine (25.8%) in post-menopausal women, while prevalence of osteopenia was high in pre-menopausal women (44.3%). Vitamin D deficiency was seen in 54.5% pre and 41.8% post-menopausal women and significant correlation of serum 25(OH)D levels (r = 0.16) was obtained only for total hip Z-score (p < 0.05). Correlation between sun index and lumbar spine BMD was marginally significant (r = 0.14, p = 0.07). Generalised linear models revealed that after adjusting for age, weight and height, percent decrease of 2.1-4.5% in BMD may be attributed to menopause.

CONCLUSION

Age, weight, height, menopause, low intakes of calcium and low 25(OH)D along with poor sunlight exposure are the major factors contributing to bone loss in Indian women above 40 years of age.

Relatively high bone mineral density in Chinese adolescent dancers despite lower energy intake and menstrual disorder

OBJECTIVE

The effect of dietary restriction, intense exercise and menstrual dysfunction on bone mineral density remains controversial. The aim of this study was to assess the skeletal health status and relationship between bone mineral density and nutrient intake, menstrual status, estrogen level and other factos in Chinese adolescent dancers.

METHODS

Sixty dancers and 77 healthy controls underwent measurements of bone density, body composition, and estrogen level. Nutrient intake, menstrual status and physical activity were assessed with questionnaires. The correlation between these factors were analyzed.

RESULTS

The dancers under study had a significantly lean body mass index (18.3 +/- 1.4 kg/m2 vs. 21.7 +/- 3.1 kg/m2), lower percentage of body fat (0.25 +/- 0.05 vs. 0.34 +/- 0.04) and later age at menarche (14.0 +/- 0.9 y vs. 13.0 +/- 1.3 y), and the estrogen level, daily calorie and fat intake in them were also lower than in the controls. All the dancers undertook intensive physical activity every day and up to 69% of them suffered from irregular menarche. Yet they had relatively high BMD and BMC of the total body and legs than the controls after adjusting for BMI and age. Site-specific BMD was positively correlated to BMI, body composition and training hours per week and negatively correlated to the age at menarche and menstrual frequency.

CONCLUSIONS

The relatively high BMD and BMC of the dancers at the total body and legs were probably caused by high levels of weight-bearing physical activity. To ameliorate disordered eating, especially low energy intake might be helpful to prevent the Triad and to improve the bone health in adolescent dancers.

Poor glycemic control is associated with low BMD detected in premenopausal women with type 1 diabetes

SUMMARY

The etiology of bone fragility in individuals with type 1 diabetes is unknown. This study demonstrated that bone turnover favors resorption and that poor glycemic control is associated with low bone mineral density (BMD) and low bone turnover, in premenopausal women with type 1 diabetes. The results could inform future interventions.

INTRODUCTION

Low BMD and fracture may be complications of type 1 diabetes. We sought to determine the roles of bone turnover and glycemic control in the etiology of low BMD.

METHODS

Premenopausal women from the Wisconsin Diabetes Registry Study and matched controls were compared (n = 75 pairs). Heel and forearm BMD were measured, and hip and spine BMD were measured in a subset. Markers of bone formation (osteocalcin) and resorption (NTx), and glycemic control (HbA1c) were determined.

RESULTS

Age ranged from 18 to 50 years with a mean of 28, and 97% were Non-Hispanic white. Among women with diabetes, mean disease duration was 16 years and current HbA1c was 8%. Compared to controls, women with diabetes had a high prevalence of previous fracture (37% vs. 24%) and low BMD for age (heel or forearm: 49% vs. 31%), low heel and forearm BMD, and low osteocalcin levels. Levels of NTx were similar, suggesting uncoupled turnover favoring resorption. Poor glycemic control was associated with low BMD at all bone sites except the spine, and with low osteocalcin and NTx levels.

CONCLUSIONS

Optimal glycemic control may prevent low BMD and altered bone turnover in type 1 diabetes, and decrease fracture risk.

Rationality/anti-emotionality personality and dietary habits in a community population in Japan

Background

There are no strong and consistent predictors of dietary habits although some associations have been shown with psychological factors. The purpose of the present study was to examine the relationships between the rationality and anti-emotionality (R/A) personality and dietary consumption in a Japanese community.

Methods

The Takayama study is a community-based cohort study on diet and cancer in Gifu, Japan, and was initiated on September 1, 1992. Cross-sectional analyses were conducted on dietary and lifestyle data. The consumption of 169 food and beverage items was measured along with portion size by using a food frequency questionnaire. Questions regarding the R/A-personality scale and lifestyle habits were included in the questionnaire. The participants were 28077 adults (13082 males and 14995 females) aged 35 years and over.

Results

Both males and females with high R/A-personality scores (i.e., high degree of rational thought and emotional repression) consumed more soy products, green and yellow vegetables, other vegetables, and seaweed than the other participants. Males with high R/A-personality scores drank fewer alcoholic beverages, and females with high scores were found to snack less on sweet and salty foods than the other participants. Males with high R/A-personality scores showed higher consumption of meat and dairy products, and females with high scores showed higher consumption of fish, shellfish, and eggs than those with low R/A-personality scores.

Conclusion

The R/A-personality scale may differentiate dietary habits in males and females in a Japanese community.

Long-term fracture risk among women with proven endometriosis

OBJECTIVE

To determine whether women with pelvic endometriosis are at increased fracture risk.

DESIGN

Historical cohort study.

SETTING

Population-based investigation using the data resources of the Rochester Epidemiology Project.

PATIENT(S)

From Olmsted County, Minnesota, 987 women with endometriosis that was first surgically visualized or histologically proven in 1970-1989.

INTERVENTION(S)

None, observational study.

MAIN OUTCOME MEASURE(S)

Follow-up for fractures through complete inpatient and outpatient community medical records.

RESULT(S)

In 17,408 person-years of follow-up, 256 women experienced 449 different fractures. The cumulative incidence after 20 years (30.8%) was not elevated relative to that expected (30.6%). The independent predictors of any fracture included age (hazard ratio [HR] per 10 years: 1.61; 95% confidence interval [CI] 1.42-1.84]), corticosteroid use (HR: 2.78; 95% CI 1.48-5.24), prior hip, spine, or forearm fracture (HR: 1.82; 95% CI 1.10-3.02), and use of the selective estrogen receptor modulators, tamoxifen or raloxifene (HR: 4.34; 95% CI 2.14-8.81); physical activity was protective (HR: 0.40; 95% CI 0.18-0.88). There was no significant influence on fracture risk of surgery or other medical treatments for endometriosis.

CONCLUSION(S)

Despite reported adverse effects of treatment on bone density, there was no overall increase in long-term fracture risk in this unselected cohort of women with proven endometriosis.

Influence of pattern of menopausal transition on the amount of trabecular bone loss. Results from a 6-year prospective longitudinal study

INTRODUCTION

Bone density is lower in postmenopausal than in premenopausal women. Recent findings have suggested that accelerated bone loss already begins before menopause. Despite numerous cross-sectional studies on menopause-related bone density, longitudinal data on perimenopausal bone density changes are scarce. This study sought to characterize the dynamics of changes leading to postmenopausal osteopenia and to possibly find the time point at which accelerated bone loss begins.

METHODS

We prospectively followed 34 pre-, peri- and early postmenopausal women without prior external hormone use, measuring their lumbar spine trabecular bone density with quantitative computer tomography at 0, 2 and 6 years. The analysis of the changes over time was done in a tri-parted fashion, since menopausal status changed variably for individual subjects: we grouped the participants according to their currently valid menopausal classification for prospective (baseline classification), interim (2 years) and retrospective (6-year classification) analysis.

RESULTS

Six different patterns of menopausal transition were identified in our sample. Bone loss in the groups not reaching postmenopause during 6 years of observation was >50% of the maximum bone loss observed during the study period. Invariably for all analyses, the perimenopausal phase with estrogen levels still adequate was associated with the greatest reduction of trabecular bone mineral density, reaching 6.3% loss annually in the lumbar spine. By comparison, the average rate of loss was slower in the early postmenopause; total bone loss differed by pattern of menopausal transition (one-way ANOVA p<0.05).

CONCLUSION

The presented data for the first time show the perimenopausal course of trabecular bone loss (as measured by QCT of the lumbar spine). Acceleration of bone loss during perimenopause reached half-maximal values of the total bone loss measured around menopause, despite adequate serum estradiol levels.

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.

Menstrual and Reproductive Factors and Fracture Risk: The Leisure World Cohort Study

BACKGROUND

Because menopausal estrogen is related to the development of osteoporosis, we investigated the potential associations of the estrogen-related events of menarche, pregnancy, and menopause with fracture risk in a population-based, prospective study of older women.

METHODS

The Leisure World Cohort was established in the early 1980s when residents of a California retirement community, including 8877 women, completed a health survey. Incident fractures of the hip (n = 1220), wrist (n = 463), and spine (n = 613) incurred over two decades were identified from four follow-up questionnaires, hospital discharge records, and (for hip fracture) death certificates. Hazard ratios (HR) adjusted for age and other potential confounders were calculated using proportional hazards regression.

RESULTS

Late age at menarche was associated with decreased hip fracture risk (HR = 0.84, 95% CI 0.72-0.98, for age > or = 14 vs. < or = 12 years) but was unrelated to fractures at other sites. Hip fracture risk was also reduced in women who had been pregnant (HR = 0.83, 95% CI 0.72- 0.95). Women who reported menopause at age 45+ had a lower risk of wrist fracture compared with those with menopause at age < or = 44 (HR = 0.74, 95% CI 0.58-0.95 for ages 45-54; HR = 0.71, 95% CI 0.49-1.04 for ages 55+). Although fracture risks did not differ between ever and never users of menopausal estrogen, recency since last use was related to wrist fractures (HR = 1.09, 95% CI 1.03-1.16 for each 5 years since last years).

CONCLUSIONS

The estrogen-related events of menarche, pregnancy, and menopause were not associated with osteoporotic fracture risk in a consistent manner. Other factors related to these events may be influencing development of osteoporosis and the likelihood of sustaining a fracture in older women.

Ovarian aging and bone metabolism in menstruating women aged 35–50 years

OBJECTIVES

The aim of this study was to investigate the relationships between the levels of gonadotrophins, estradiol, inhibin-b and bone mass and turn-over in regularly menstruating women aged 35-50 years.

METHODS

The study group included 87 healthy volunteers from the community aged 35-50 years. Bone mineral density of lumbar vertebras, wards triangle, throchanter, femur neck, bone resorption and formation markers were studied as well as the serum levels of gonadotrophins, estradiol and inhibin-b on the day 3 of menstrual cycle.

RESULTS

The gonadotrophin levels showed significant positive relation with age, whereas inhibin-b and estradiol levels showed significant negative correlation with age. The gonadotrophins and estradiol levels had no significant association with bone mass and bone formation markers. Increased gonadotrophin (p < 0.001) levels and decreased inhibin-b (p < 0.01) levels independent from age were correlated with increased bone resorption. Gonadotrophins, estradiol, age, inhibin-b, body mass index (BMI) were the confounding factors for bone resorption (p = 0.015, R(2) = 0.190) and lumbar bone mass (p = 0.041, R(2) = 0.148). Multivariate analysis showed an independent contribution of inhibin-b and BMI in the prediction of lumbar bone mass.

CONCLUSION

This findings suggested that estradiol was not the only factor responsible for bone loss and decrease in reproductive function because increased gonadotrophins and decreased inhibin-b levels might trigger some changes in bone metabolism prior to the menopause.

Medieval trabecular bone architecture: the influence of age, sex, and lifestyle

Osteoporosis has become a growing health concern in developed countries and an extensive area of research in skeletal biology. Despite numerous paleopathological studies of bone mass, few studies have measured bone quality in past populations. In order to examine age- and sex-related changes in one aspect of bone quality in the past, a study was made of trabecular bone architecture in a British medieval skeletal sample. X-ray images of 5-mm-thick coronal lumbar vertebral bone sections were taken from a total of 54 adult individuals divided into three age categories (18-29, 30-49, and 50+ years), and examined using image analysis to evaluate parameters related to trabecular bone structure and connectivity. Significant age-related changes in trabecular bone structure (trabecular bone volume (BV/TV), trabecular number (Tb.N), trabecular separation (Tb.Sp), and anisotropic ratio (Tb.An)) were observed to occur primarily by middle age with significant differences between the youngest and two older age groups. Neither sex showed continuing change in trabecular structure between the middle and old age groups. Age-related changes in bone connectivity (number of nodes (N.Nd) and node-to-node strut length (Nd.Nd)) similarly indicated a change in bone connectivity only between the youngest and two older age groups. However, females showed no statistical differences among the age groups in bone connectivity. These patterns of trabecular bone loss and fragility contrast with those generally found in modern populations that typically report continuing loss of bone structure and connectivity between middle and old age, and suggest greater loss in females. The patterns of bone loss in the archaeological samples must be interpreted cautiously. We speculate that while nutritional factors may have initiated some bone loss in both sexes, physical activity could have conserved bone architecture in old age in both sexes, and reproductive factors such as high parity and extended periods of lactation could have played a key role in female bone maintenance in this historic population. The study of qualitative elements (such as trabecular architecture) is vital if we are to understand bone maintenance and fragility in the past.

Estrogen therapy in systemic lupus erythematosus

Given the female preponderance of systemic lupus erythematosus (SLE) in humans, the adverse effects of female gender and sex hormones in murine lupus, and numerous reports (retrospective, often anecdotal and uncontrolled) that describe a temporal association between estrogen exposure and development or exacerbation of SLE, it is tempting to accept that estrogens and SLE simply do not mix. While there are valid concerns regarding the use of exogenous estrogens in women with SLE, there are also potential health benefits to be considered. Oral contraceptives (OCs) offer effective birth control and may be bone protective in corticosteroid-treated patients. Recent studies, albeit retrospective, suggest that OCs are well tolerated in patients with SLE. Several salutary effects of postmenopausal estrogens assume particular importance in SLE where the risks of osteoporosis, exaggerated by menopause (natural or cyclophosphamide-induced) and corticosteroids, are substantial. However, the results of the Women's Health Initiative trial significantly limit the use of hormone replacement therapy in the general population, and raise particular concern for SLE patients. Other exogenous hormones (clomifene, gonadotropins, gonadotropin-releasing hormones) may be used to elevate levels of endogenous estrogen and to stimulate ovulation in patients with diminished fertility. Patients with inactive or stable/moderate disease and at low risk for thrombosis may benefit from OCs and other hormonal therapies without a change in lupus activity. Large prospective, double-blind, placebo-controlled studies inclusive of all ethnic groups should provide the basis for more definitive recommendations.

Bone mineral density in women aged 40–49 years using depot-medroxyprogesterone acetate, norethisterone enanthate or combined oral contraceptives for contraception

Most studies show that depot-medroxyprogesterone acetate (DMPA) has a negative effect on bone mass. There are conflicting reports with respect to recovery of bone mass with long-term use of DMPA. No information is available on the effect of norethisterone enanthate (NET-EN) on bone mass, and combined oral contraceptives (COCs) have not been found to be associated with loss of bone mass. The aim of this study was to investigate bone mineral density (BMD) in older women (40-49 years) in relation to use of DMPA, NET-EN and COCs for at least 12 months preceding recruitment into the study. One-hundred twenty-seven users of DMPA, 102 NET-EN users and 106 COC users were compared to 161 nonuser controls. Bone mineral density was measured at the distal radius and midshaft of the ulna using dual X-ray absorptiometry. There was no significant difference in BMD between the four contraceptive user groups (p=.26) with and without adjustment for age. Although a small decrease in BMD was noted in the age range of 40-49 years, this was not statistically significant (p=.7). The BMD was found to be significantly associated with body mass index (BMI) (p<or=.0001) at both measurement sites, with an increase of one unit of BMI translating to an increase of 0.0044 g/cm2 in radius BMD. Follicle-stimulating hormone (FSH) level >or=25.8 mIU/mL was associated with a decrease of 0.017 g/cm2 in radius BMD relative to women with FSH <25.8 mIU/mL. Significant interaction between FSH and BMI in their effect on BMD was observed (p=.006). This study found no evidence that long-term use of DMPA, NET-EN and COCs affects BMD in this population.

The effect of the menstrual cycle on optic nerve head analysis in healthy women

PURPOSE

To determine the effect of the menstrual cycle on optic nerve head topographic analysis in normally menstruating, healthy women.

MATERIAL AND METHODS

The study included single eyes selected randomly from each of 52 healthy women with regular menstrual cycles. All subjects underwent a complete ocular examination. Optic nerve head topographic analyses were performed using a confocal scanning laser ophthalmoscope, the Heidelberg Retinal Tomograph II (HRT II, software version 1.6). The analyses were repeated three times during the menstrual cycle: in the follicular phase (days 7-10 of the cycle), at ovulation, and in the late luteal phase (days 1-3 before menstrual bleeding). Serum oestradiol, progesterone and luteinizing hormone levels were measured at each menstrual phase.

RESULTS

Fourteen subjects were excluded from the study. The mean age of the subjects (n = 38) was 25.6 +/- 3.7 years (range 21-34 years). Blood oestradiol levels were significantly lower in the late luteal phase (35.8 pg/ml) (p < 0.0001). The mean disc area of the subjects was 1.94 +/- 0.33 mm(2). The neuroretinal rim area decreased significantly during the luteal phase (p < 0.001). However, the linear cup : disc ratio, cup : disc area ratio and the cup area were significantly higher during the luteal phase (p < 0.001).

CONCLUSION

These observations raise the possibility that sex hormone fluctuations which occur during a normal menstrual cycle in healthy women significantly alter neuroretinal rim area and cup variables of the optic nerve head. These findings should be taken into consideration in the clinical follow-up of young women with glaucoma.

Risk factors for low bone mineral density and the 6-year rate of bone loss among premenopausal and perimenopausal women

Risk factors that are associated with lower bone mineral density (BMD) may not necessarily be associated with increased bone loss among premenopausal and perimenopausal women. We determined risk factors for lower premenopausal and perimenopausal BMD while simultaneously determining risk factors for increased 6-year rate of bone loss among women aged 24-50 years within a population-based prospective cohort study. BMD of the lumbar spine and femoral neck, reported as t scores, were measured five times within the 6-year study among 614 women who were between the ages of 24 and 44 in 1992/1993. Rates of bone loss were calculated from the repeated BMD measurements. Risk factors for lower BMD over time at the lumbar spine included history of any fracture ( P=0.005). The major risk factor for lower BMD over time at the femoral neck was family history of osteoporosis ( P<0.002). The major protective factor for greater BMD over time at both skeletal sites was additional body weight ( P<0.0001). Other protective factors for greater BMD over time at the femoral neck were modest alcohol consumption ( P=0.0002) and high-school sports participation ( P=0.002). Risk factors for greater bone loss at either skeletal site included postmenopausal status ( P<0.0001 at the lumbar spine; P=0.01 at the femoral neck), and the reporting of a reproductive cancer ( P<0.0001 at the lumbar spine; P=0.0008 at the femoral neck). Body weight was protective against bone loss at both skeletal sites ( P<0.0001). Baseline age, calcium intake, smoking, and current physical activity were not associated with BMD or bone loss. The understanding of the relative importance of risk factors for both low BMD and bone loss may assist in the identification of women at greater risk for subsequent low postmenopausal BMD.

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.

Ovarian hormones in premenopausal women: variation by demographic, reproductive and menstrual cycle characteristics

BACKGROUND

Ovarian function influences many areas of concern in women's health, including breast cancer and other chronic diseases. However, ovarian function has been little studied in healthy, premenopausal women, partly because of cyclical variation.

METHODS

We measured biomarkers of ovarian function (daily urinary metabolites of estrogen and progesterone) among 411 women age 18-39 years, who were Kaiser Permanente members in Northern California in 1990-1991. We have summarized the hormone metabolite levels of about 1,500 cycles and examined their associations with demographic and menstrual cycle characteristics.

RESULTS

Cycles with a short follicular phase showed elevations of 10-13% in both baseline (days 1-5) and average follicular-phase estrogen metabolite levels, as well as some elevations in progesterone metabolites. Progesterone metabolite levels were directly related to the length of the luteal phase. Compared with whites, Hispanics had estrogen metabolite levels that were 7-13% higher in the follicular and luteal phases, whereas nonwhite, non-Hispanic women (primarily Asians) had slightly lower levels. Generally, women with a prior pregnancy or those with a later age at menarche had lower estrogen metabolite levels, whereas women with prior induced abortions had higher levels. Luteal-phase progesterone metabolite levels tended to be lower among women who were overweight, were less educated, were older at their first livebirth, or had an induced abortion.

CONCLUSIONS

Some menstrual cycle characteristics provide a crude surrogate of the hormonal milieu, particularly luteal-phase length and progesterone levels. Hormone levels varied by reproductive characteristics, potentially explaining their relevance to breast cancer risk.

Risk of low bone density in women attending menopause clinics in Italy

OBJECTIVE

In order to offer data on the epidemiological profile of women with low bone density (LBD), we have considered information collected in the framework of a large cross-sectional study conducted on women around menopause attending a network of first level outpatients menopause clinics in Italy.

METHODS

During 1997 and 2000, a large cross sectional study was conducted on the characteristics of women around menopause attending a network of first level outpatients menopause clinics in Italy for general counseling about menopause or treatment of menopausal symptoms. Eligible for the study were women consecutively observed during the study period. Up to March 2000 a total of 42464 women (mean age 53 years) were observed at the 268 participating centers. Bone mass density was measured in 25113 cases, which are considered in this analysis. LBD (i.e. osteopenia or osteoporosis) was defined according to WHO classification.

RESULTS

The frequency of LBD increased with age: in comparison with women aged < or =51 years, the odds ratio (OR) of LBD was 1.5 and 2.2, respectively, in women aged 52-55 and > or =56. No association emerged between LBD and parity: in comparison with nulliparae, the OR of LBD were 1.1 and 1.0, respectively, in women reported 1 or 2 or more full term pregnancies. Smokers were at increased risk of LBD, the corresponding OR being for smokers, in comparison with non smokers, 1.2 (95% confidence interval, CI, 1.1-1.3). In comparison with women in the lower tertile of body mass index, the OR of LBD decreased in subsequent tertiles, being, respectively, 0.9 and 0.7 in the middle and highest tertile. The OR of LBD was 2.2 in postmenopausal women, in comparison with premenopausal ones and the OR decreased increasing age at menopause. Ever OC users were at slightly decreased risk of LBD: in comparison with never OC users, the OR was 0.9 (95% CI 0.8-1.0) in ever OC users.

CONCLUSION

The results of this large study confirm, in a Southern European population, the association of age at menopause and body mass on the risk of LBD, and suggest that ever OC women are at decreased risk of LBD.

Gender differences in acute mountain bike racing injuries

OBJECTIVE

To evaluate injury rates and patterns in off-road bicycle racing, and to compare the findings in male and female cyclists.

SETTING

The study was conducted from 1994-2001 at a large off-road bicycling competition held for 4 days each summer at Mammoth Mountain, California.

DESIGN

Injured cyclists were evaluated at the first aid station or at the local hospital. Registration data were used to estimate the number of male and female competitors in each race.

PARTICIPANTS

Cyclists who sustained an injury during a race and were unable to finish the race due to the injury were included in the study. 22 female subjects and 71 male subjects met the inclusion criteria during the 8-year study period. There were a total of 20,769 race participants during the study period.

MAIN OUTCOME MEASURES

Injuries were categorized, and injury rates were calculated.

RESULTS

The overall injury rate during the study period was 0.77% (22/2,869) for women versus 0.40% (71/17,900) for men (p = 0.01). Fractures were sustained by 45.5% (10/22) of female subjects versus 21.1% (15/71) of male subjects (p = 0.03). Odds ratios indicate that overall, women were 1.94 times more likely than men to sustain an injury and 4.17 times more likely to sustain a fracture.

CONCLUSIONS

These data suggest that although participation in this sport is higher among men, the risk of injury is greater for women.

Reproductive health in SLE

Oral contraceptives containing oestrogens and hormone replacement therapy are generally not prescribed for women with systemic lupus erythematosus (SLE). The concern regarding oestrogens is based on the greater incidence of SLE in women, abnormalities of oestrogen metabolism, murine models of lupus, several anecdotes of patients having disease flares while receiving hormones, and one retrospective study in patients with pre-existing renal disease. For healthy women and those with SLE, there are clinical settings in which exogenous oestrogens provide benefit. For pre-menopausal women, these include provision of safe and effective birth control, protection against bone loss, and the consideration of oral contraceptives to preserve fertility in patients taking cyclophosphamide. For post-menopausal women, these include treatment of hot flushes and vaginal dryness, prevention of osteoporosis and, more controversial, prevention of atherosclerosis. Other exogenous hormones (clomiphene citrate, gonadotropins, gonadotropin-releasing hormones) may be used to elevate levels of endogenous oestrogen and stimulate ovulation in patients with diminished fertility. This chapter focuses on three broad categories: birth control, assisted reproduction and hormone replacement.

Cross-sectional measurement of nutrient intake among adolescents in 1996

BACKGROUND

Many components are involved in an assessment of diet and health among youth. To address these issues and document the major contributions of fat, fiber, vitamins, and minerals to the diet, we analyzed baseline cross-sectional data from a cohort of 16,882 youth.

METHODS

Cross-sectional analyses were conducted on the Growing Up Today Study dietary data reported by 16,882 9- to 14-year-olds in 1996. The adolescent food frequency questionnaire was used to assess this age group's eating habits. Arithmetic means and standard deviations were calculated on energy-adjusted and unadjusted data.

RESULTS

Mean intake (including vitamin/mineral supplementation) for all nutrients met 100% of the RDAs, except calcium for girls. Comparing the servings of foods with the USDA Food Pyramid, neither boys nor girls met recommended number of servings except for dairy. Overweight participants consumed fewer kilocalories and lower levels of nutrients than their nonoverweight peers.

CONCLUSION

These cross-sectional data from 1996 indicate that this cohort is consuming foods and nutrients comparable with national data of less fat and more carbohydrates in their diet. Overweight participants have similar dietary patterns except for total energy. The cohort's diet (with vitamin/mineral supplementation) is meeting the RDAs, but actual foods consumed suggest a lack of balance in the diet.

Long-term fracture risk among infertile women: a population-based cohort study

Nulliparity has been linked to bone loss and fractures, but the contribution of infertility is unclear. The purpose of this study was to assess the long-term risk of fractures among infertile women. In a population-based retrospective cohort study, all 658 Olmsted County, Minnesota, women with infertility (failure to conceive after 1 year despite intercourse without contraception) first diagnosed at Mayo Clinic in 1935-1964 were followed for fractures. Risk was assessed by comparing new fractures of each type to the number expected from sex-specific and age-specific fracture rates in the general population (standardized incidence ratios [SIR]). During 18,130 person-years of follow-up, 184 women experienced at least one fracture when 291 would have been expected on the basis of fracture incidence rates in the general population (SIR 0.6, 95% CI 0.5-0.7). There was no increase in proximal femur fractures (SIR 1.0, 95% CI 0.6-1.6) and a statistically significant decrease in the risk of distal forearm fractures (SIR 0.7, 95% CI 0.5-0.97), two of the three sites traditionally associated with osteoporosis. By contrast, there was a significant increase in subsequent vertebral fractures (SIR 1.9, 95% CI 1.4-2.4) that was consistent across divergent causes of infertility and reported menstrual patterns. Although an apparent increase in the risk of vertebral fractures requires further investigation, we saw no indication of an increase in limb fractures, suggesting that infertility does not have long-term adverse skeletal effects like those reported for athletes and dieters with irregular menses.

Bone health and osteoporosis

Good bone health is important to everyone, regardless of age. Osteoporosis is a preventable disease, and steps for increasing bone mass should begin at an early age. To increase bone mass, much of the recent evidence suggests that the best time for intervention with calcium or exercise may be during the prepubertal years. In the older female athlete, BMD is typically well above normal, but even young amenorrheic athletes can have bone density values equal to that of an elderly osteoporotic woman. Myriad treatment options are available for the person with low bone mass, but prevention is a much more preferable alternative.

[Multiple genetic typing (vitamin D receptors and estrogens) in the assessment of the risk of fractures]

BACKGROUND

Several studies suggested that some vitamin D receptor (VDR) and estrogen receptor (ER) polymorphisms influence bone mass. However, others did not confirm these results. This study was undertaken to determine if the genotypes revealed by the combined analysis of VDR and ER polymorphisms are associated with clinically significant differences in peak bone mass and the risk of osteoporotic fractures.

PATIENTS AND METHODS

Restriction fragment length polymorphisms of VDR were determined with the enzymes Bsml, Apal, Taql, and Fokl. Enzymes Xbal and Pvull were used as polymorphic markers of the ER. The study group comprised 149 young control women (18-34 years), 66 postmenopausal controls, 99 women with hip fracture and 76 women with osteoporotic vertebral fractures. Bone mineral density (BMD) was measured by DEXA.

RESULTS

We did not find significant differences in lumbar spine or hip BMD among young women with different genotypes (determined with either single or multiple polymorphic markers). Likewise, there were no differences in the frequency distributions of VDR or ER alleles between control and fractured women. The study had a 77% power to detect a fracture odds ratio of 2 in case of genotypes present in at least 15% of the population.

CONCLUSIONS

These results suggest that the polymorphic markers used in this study do not have enough discriminant power to be clinically useful in the assessment of fracture risk.

The effects of an educational intervention on calcium intake and bone mineral content in young women with low calcium intake

PURPOSE

This study evaluated whether a combined behavioral and dietary intervention would affect young women's calcium intake and bone mineral content (BMC).

DESIGN

The design was a two by three mixed design with one between-subjects factor (treatment vs. control) and one within-subjects factor (time--baseline, 3-month, and 6-month).

SETTING

The study was conducted in a university setting in Memphis, Tennessee.

PARTICIPANTS

A total of 80 premenopausal women (ages 18 to 30) with low baseline calcium intake (< 700 mg/d) were included in the analyses. There were 40 women in the treatment group and 40 women in the control group.

MEASURES

Hertzler and Frary's rapid assessment questionnaire was employed to evaluate calcium intake, and dual-energy x-ray absorptiometry (DEXA) was employed to assess BMC.

RESULTS

Repeated measures analysis of variance (RM ANOVA) was employed to analyze results. Results indicated that women in the treatment group made greater increases in total calcium intake and supplemental calcium than women in the control group and that all women made significant increases in dietary calcium intake. Additionally, analyses of BMC revealed that women in the treatment group did not experience significant changes in total BMC, and women in the control group experienced significant losses in total BMC.

CONCLUSIONS

In the current study, women were losing BMC, and the women who made the largest increases in calcium intake were able to retard this bone loss. There is increasing evidence that dietary calcium intake in young people is extremely low, and the results of the current study highlight the need for much more intensive evaluations investigating the factors that are positively associated with premenopausal bone mineral change.

Menstrual history and bone density in young women

Adequate levels of reproductive and pituitary hormones are needed for the initiation and maintenance of regular menstrual cycles as well as for the achievement of peak bone mineral density (BMD). Therefore, in the absence of direct hormone measures, menstrual history may serve as a surrogate for the adequacy of hormonal functioning and be a marker for bone status in young women. In our cross-sectional study of white college women aged 19-26 years, we examined the association of six characteristics of menstrual history with bone density at the lumbar spine and the femoral neck. To characterize associations, we used multiple linear regression models that also accounted for the contribution of body mass index, dietary calcium intake, height, level of physical activity, smoking, and alcohol use. The associations between each of the six menstrual characteristics and BMD were stronger at the lumbar spine than at the femoral neck. Age at menarche explained the most variance at both the lumbar spine (partial r2 x 100 = 5.9%) and the femoral neck (partial r2 x 100 = 2.1%). For each year that menarche was delayed, bone density was lower by -0.023 g/cm2 (p = 0.0024) at the lumbar spine and -0.0129 g/cm2 (p = 0.0565) at the femoral neck. At the lumbar spine, a higher number of lifetime menstrual cycles was also significantly associated with increased bone density (adjusted beta = 0.0010, p = 0.0052, partial r2 x 100 = 4.4%). This association was not significant after adjusting for age at menarche. Neither reproductive years (age - age at menarche) nor a history of irregular cycles (either at menarche, in the past year, or ever) was associated with bone density at either site. Menstrual function appears to affect the bone density of these young women. Studies that include measures of reproductive and pituitary hormones are needed to further explore the role of hormones in the potential link between menstrual history and bone density.

Dietary calcium and bone density in adolescent girls and young women in Europe

The objective of this study was to investigate the association between dietary calcium intake and radial bone density among young women, over the whole range of intake and at different levels of calcium intake. The study design was a cross-sectional, observational multicenter investigation in six European countries. One thousand one hundred and sixteen healthy Caucasian girls aged 11-15 years and 526 women aged 20-23 years participated, after having been selected from larger population samples to represent a large range in calcium intake. Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry at the ultradistal and middistal radius. Calcium intake was assessed with 3-day food records. Other potential determinants of BMD were measured by anthropometry or questionnaires. Mean calcium intake among the girls varied between 609 mg/day in Italy and 1267 mg/day in Finland; intakes for women were in a similar range. After adjustment for height, weight, and age at menarche for the women, and adjustment for age, height, weight, Tanner stage, and bone area for the girls, radial BMD at both sites did not significantly vary among quartiles of calcium intakes for both age groups. In multivariate linear regression, calcium was weakly positively associated with BMD at both sites in the girls (per 100 mg of calcium: beta = 0.57 mg/cm2, p = 0.03 for middistal BMD and beta = 0.56 mg/cm2, p = 0.01 for ultradistal BMD). For middistal BMD, the association was observed predominantly in pre-menarcheal girls. The associations were no longer statistically significant after full adjustment for all determinants of BMD, except again in pre-menarcheal girls. Radial BMD in the women was not associated with calcium intake, except after full adjustment for determinants of BMD, when ultradistal BMD became inversely associated with calcium intake (per 100 mg beta = -1.02, p = 0.03); this finding was due to results in one of the countries and not found in other countries. There was no evidence for a different relation between calcium and BMD at different levels of intake; although there was a positive association at calcium intake levels < 600 mg/day, the interaction was not significant and there was no consistent trend over intake categories. These results do not support the hypothesis that dietary calcium is a determinant of peak BMD in European women, for a wide range of intake. This study does not provide evidence that Recommended Dietary Allowances for calcium should be increased.

Bone mineral density and depression: a community study in women

In a community sample of 102 Portuguese white women we evaluated the relationship between osteoporosis and indexes of psychopathology and well-being. Depressive symptoms were assessed by the Beck Depression Inventory (BDI), psychopathology by the Hopkins Symptom Checklist-90 Revised (SCL-90-R), and quality of life using the Psychological General Well-Being Index. A questionnaire comprising social, demographic, clinical, and behavioral characteristics was also used. The sample prevalence of osteoporosis was 47.1%. Women with osteoporosis presented significantly higher scores on the total BDI (16+/-9 vs. 13+/-10, p=0.045) and lower scores in the hostility (0.8+/-0.6 vs. 1.2+/-0.7, p=0.012) and phobic anxiety (1.1+/-0.8 vs. 1.5+/-0.9, p=0.041) subscales of the SCL-90-R. No differences were found regarding mean general well-being scores (62+/-17 vs. 64+/-19, p=0.665). This study showed that women with osteoporosis have significantly higher levels of depressive symptoms and a corresponding higher prevalence of depression, independent of other factors strongly associated with osteoporosis, such as age or body mass index.

The reproducibility of ultrasound bone measures in a triethnic population of pregnant adolescents and adult women

We used bone ultrasound technology with its measurement of attenuation (broadband ultrasound attenuation [BUA] as dB/MHz) and sound velocity (speed of sound as m/s) for assessing the quantitative ultrasound index (QUI) summary measure in a triethnic population of 280 pregnant women. The study purpose was to describe the reproducibility of the ultrasound technology and determine if the correlations of age, weight, and ethnicity with the bone status measures in this population are consistent with the correlations of age, weight, and ethnicity that have been reported with other technologies that measure bone mass. We evaluated the first 280 women enrolled in our longitudinal study of lead turnover from maternal bone during pregnancy and lactation. Enrollees were pregnant, aged 12-29 years, and self-classified as black, white, or Hispanic. Bone ultrasound was measured twice at entry to prenatal care, which, on average, was at 14 weeks gestation. Reproducibility was described with intraclass correlations and the standard error of measurement. Age, weight, and ethnicity were associated with bone status measures using Spearman correlations and generalized linear models. The reproducibility of the summary bone measure, QUI, was high (96-97%). Variation in age and ethnicity did not alter reproducibility; however, the reproducibility of the attenuation measure (BUA as dB/MHz) lessened with increasing weight, declining from 95% to 89%. Since this attenuation is included in the summary QUI measure, there was a slight, and nonsignificant, decline in QUI reproducibility (from 97% to 96%) as women increased in size. There were no statistically significant differences in mean bone ultrasound measures according to age, where ages ranged from 12-29 years. Women who categorized themselves as black had, on average, an 8.5% greater QUI than did women who classified themselves as Hispanic or white. There were no significant pair-wise differences in mean ultrasound measures of bone between women classifying themselves as Hispanic or white. The use of ultrasound is a highly reproducible measure to assess bone characteristics in a population of pregnant adolescent and young adult women and its summary measure of bone mass is correlated with ethnic as well as body size characteristics.

Reproductive factors and fatal hip fractures. A Norwegian prospective study of 63,000 women

STUDY OBJECTIVE

The aim of the study was to investigate the impact of reproductive variables (age at menarche, menopause, first and last birth as well as parity, lactation, and abortions) on hip fracture mortality.

DESIGN AND SETTING

A prospective study in Norway with more than 60,000 women followed up for 29 years. A total of 465 deaths as a result of hip fracture were recorded.

MAIN RESULTS

Statistically significant linear relations (p < or = 0.02) were found between both age at menarche and length of reproductive period (defined as age at menopause to age at menarche) and the mortality of hip fractures in women aged less than 80. The death rate for women with a late menarche (> or = 17 years) was twice that of the women with relatively early menarche (< or = 13 years). Compared with women with less than 30 years between menopause and menarche, the mortality rate ratio in women with more than 38 reproductive years was 0.5. We also found an inverse relation with age at first birth.

CONCLUSIONS

This study supports by hypothesis that an early menarche and a long reproductive period protect against hip fracture mortality. High age at first birth may also be protective.

[Prevention of glucocorticoid induced osteoporosis]

INTRODUCTION

It is generally accepted that moderate to high dose glucocorticoid therapy is associated with bone loss and increased fracture risk. The degree of bone loss is closely related to the cumulative corticosteroid dose and the highest rate of bone loss is observed in the first 3 to 6 months of therapy.

CURRENT KNOWLEDGE AND KEY POINTS

Optimal management strategies to prevent bone loss should include the use of the lowest efficacious dose of glucocorticoid. Alternate day dosing and bolus do not provide effective protection. Prevention should basically include adequate calcium intakes and additional vitamin D. All patients should be encouraged to modify their lifestyles, including smoking cessation and limitation of alcohol consumption; physical exercise for 30 minutes to 1 hour every day should also be recommended. Sodium restriction and thiazide diuretics have been shown to improve hypercalciuria that sometimes accompanies glucocorticoid therapy. Hormone replacement therapy should be recommended in postmenopausal women, while estrogen-containing oral contraceptives should be advocated in young women with menstrual irregularities, except for patients with systemic lupus erythematosus.

FUTURE PROSPECTS AND PROJECTS

Dual-energy X-ray absorptiometry may be useful in patient with high risk of glucocorticoid-induced osteoporosis, as it allows accurate measurements of bone mineral density. Etidronate recently proved to be efficacious in preventing bone loss and decreasing the number of vertebral fractures in menopausal women.

Oral contraception and other factors in relation to hospital referral for fracture. Findings in a large cohort study

There is good evidence that estrogens and progestogens have an important effect on bone metabolism. This article explores the relationship between oral contraceptive (OC) use and fractures occurring at various sites among the 17,032 participants in the Oxford-Family Planning Association contraceptive study, which now includes information accumulated during 310,000 woman-years of observation between 1968 and 1994. In total, 1308 women suffered at least one fracture during the follow-up period, which was largely confined to premenopausal years. When all fractures were combined, there was a modest, but highly significant trend (p < 0.001) of increasing risk with total duration of oral contraceptive use. In addition, there was statistically significant heterogeneity (p < 0.01) when overall fracture rates were examined in relation to recency of oral contraceptive use during the premenopausal lifespan. The highest relative risk (1.3, 95% CI 1.1-1.5) was for current or recent oral contraceptive users; however, viewed as a whole, no clear pattern of risk was apparent. Examination of the data for individual fracture sites (including the lower end of the radius/ulna) did not provide any evidence of a protective effect of oral contraceptive use. These results are closely similar to those reported from the Royal College of General Practitioners Oral Contraception Study in 1993.

Epidemiology of spinal osteoporosis

Approximately 30% of postmenopausal white women in the United States have osteoporosis, and 16% have osteoporosis of the lumbar spine in particular. Bone density of the spine is positively associated with greater height and weight, older age at menopause, a history of arthritis, more physical activity, moderate use of alcoholic beverages, diuretic treatment, and current estrogen replacement therapy, whereas later age at menarche and a maternal history of fracture are associated with lower levels of density. Low bone density leads to an increased risk of osteoporotic fractures. Fracture risk also increase with age. Vertebral fractures affect approximately 25% of postmenopausal women, although the exact figure depends on the definition used. Recent data show that vertebral fracture rates are as great in men as in women but, because women live longer, the lifetime risk of a vertebral fracture from age 50 onward is 16% in white women and only 5% in white men. Fracture rates are less in most nonwhite populations, but vertebral fractures are as common in Asian women as in those of European heritage. Other risk factors for vertebral fractures are less clear but include hypogonadism and secondary osteoporosis; obesity is protective of fractures as it is of bone loss. Compared with hip fractures, vertebral fractures are less disabling and less expensive, costing approximately $746 million in the United States in 1995. However, they have a substantial negative impact on the patient's function and quality of life. The adverse effects of osteoporotic fractures are likely to increase in the future with the growing number of elderly people.

Associations between body morphology and bone mineral density in premenopausal women

To investigate whether body morphology, obesity and its long time evolution were associated with lumbar and femoral bone mineral density (BMD) in premenopausal women of the same age.

DESIGN

Cross-sectional study.

SUBJECTS

72 healthy premenopausal women born in 1950 (42 years) with a regular physical activity.

MEASUREMENTS

BMD measured by dual-X-ray absorptiometry (DEXA) at lumbar spine and proximal femur; body weight, body mass index (BMI), BMI at 20 years (BMI-20), increase in BMI since age of 20 (BMI->20), body circumferences (breast, waist, hip) and their ratios (WHR, BHR, WBR), smoking and alcohol intake.

RESULTS

Lumbar spine BMD did not correlate with any anthropometric measurement. Femoral BMDs correlated positively with weight, BMI, BMI-20, breast, waist, WHR and BHR. The BMI-20 explained the 5% and the current BMI the 13% of variance of total femur BMD. After adjustment for weight or BMI, breast circumference and BHR remained significantly correlated with all femoral BMDs sites except neck. Weight was the best predictor for neck BMD (R2 = 0.08; p < 0.02), and BHR for Ward's triangle (R2 = 0.12; p < 0.01) and trochanter (R2 = 0.10; p < 0.001). Alcohol intake, cigarette smoking, and age of menarche were not related to BMDs.

CONCLUSION

In premenopausal women of the same age, lumbar spine BMD was not associated with any anthropometric measurement. Greater BHR and its long time of evolution may be determinants of greater femoral BMD (trabecular), whereas body weight may be determinant of femoral neck BMD (cortical). Further studies are needed to determine whether large breast to hip ratio may be considered as a protective factor for femoral osteoporosis.

Bone mass and hip axis length in healthy Asian, black, Hispanic, and white American youths

The primary objective of this study was to examine the associations of ethnicity, diet (calcium, protein, energy), and weight-bearing activity with dual-energy X-ray absorptiometry (DXA)-measured bone mass and hip axis length (HAL) in 423 Asians, blacks, Hispanics, and non-Hispanic Caucasians, aged 9-25 years. Bone mass was expressed as bone mineral content (BMC), bone mineral density (BMD), and bone mineral apparent density (BMAD). The data were analyzed using multiple linear regression, after stratifying for gender and pubertal stage and adjusting for height and weight. With few exceptions, Asians and Hispanics had comparable bone mass to whites at all pubertal stages. Greater femoral neck BMAD in black than white females was observed at all pubertal stages. Black males displayed greater BMD and BMAD than white males at all sites in early puberty and at the femoral neck in maturity. Calcium was positively and protein negatively related to BMAD at the femoral neck in early pubertal females. Among males, calcium was negatively associated with whole body BMC and BMD and spine BMD and BMAD in midpuberty. Weight-bearing activity was not associated with bone mass in females; in males, it was positively related only to femoral neck BMC in early puberty. There was an absence of evidence for ethnic differences in HAL among females. In males, we observed shorter HAL in mature Asians and blacks than whites. Neither diet nor activity was associated with HAL.

Cross sectional investigation of the effects of inhaled corticosteroids on bone density and bone metabolism in patients with asthma

BACKGROUND

Bone mineral density has been reduced in patients with asthma taking inhaled corticosteroids in some cross sectional studies and this could be important if treatment is continued for several decades. The possibility of confounding by age, menopausal status, physical activity and, especially, past oral steroid use has not been excluded in most studies. The present study was designed to assess the magnitude of any reduction in bone mineral density in relation to inhaled steroid use after adjusting for these factors.

METHODS

Bone mineral density (BMD), vertebral fractures, and markers of bone metabolism (serum osteocalcin, procollagen peptide I, bone-specific alkaline phosphatase, and urinary deoxypyridinoline cross links) were measured in 81 patients with asthma age 20-40 years; 34 patients (19 men) who had never had inhaled or systemic steroids and 47 (19 men) who had taken inhaled steroids for at least five years with limited exposure to systemic steroids in the past. Data relating to past medication use, physical activity, smoking, and other confounding factors were collected by questionnaire. The relation between inhaled steroid dose and duration and BMD was assessed by linear regression analysis, accounting for potential confounders including weight, exercise, and oral steroid use.

RESULTS

The 47 patients taking an inhaled steroid had a mean current dose of 620 micrograms/day (range 100-3000 micrograms), a mean duration of use of 7.8 years, and had had a mean of 0.85 courses of prednisolone in the past. There was no significant difference in mean BMD values between those who were and those who were not on inhaled steroids in men or women. However, on multivariate analysis, cumulative inhaled steroid dose was associated with a reduction in posterior-anterior (P-A) and lateral lumbar spine bone mineral density in women, equivalent to a 0.11 standard deviation reduction in bone density per 1000 micrograms/day inhaled steroid per year after adjustment for potential confounding factors (95% CI for P-A spine 0.01 to 0.22; for lateral spine 0.02 to 0.21). Previous oral steroid use was not an important confounding factor in these patients. Inhaled steroid use was not related to BMD at the wrist or hip in women or at any skeletal site in men. Women taking an inhaled steroid had lower levels of serum osteocalcin than those not taking them, although this was not dose related. Inhaled steroid use was not associated with differences in other markers of bone metabolism in men or women or with the presence of vertebral fractures.

CONCLUSIONS

Although an effect of confounding factors cannot be excluded entirely in a cross sectional study, our findings are in keeping with an effect of inhaled steroid therapy in reducing bone density in the spine in women and provide an estimate of the magnitude of this effect.

Associations of vitamin C, calcium and protein with bone mass in postmenopausal Mexican American women

We investigated the associations of vitamin C, calcium and protein intakes with bone mass at the femoral neck and lumbar spine in postmenopausal Mexican American women. Bone mass was measured by dual-energy X-ray absorptiometry (DXA) and expressed as areal (BMD, g/cm2) and volumetric (bone mineral apparent density or BMAD, g/cm3) bone mineral density. Diet was assessed using a modified version of the National Cancer Institute Food Questionnaire, which was administered by trained bilingual interviewers familiar with Mexican dietary practices. Data gathered from 125 subjects were analyzed using multiple linear regression analysis with age, body mass index (BMI), acculturation, years of estrogen use, physical activity, total energy intake, and the nutrient of interest as independent variables. Neither calcium nor calcium/protein ratio was associated with bone mineral density. There was evidence of a positive association between dietary vitamin C intake and femoral neck BMD (beta = 0.0002 g/cm2 per mg/day, SE = 0.00006, p < 0.05), but vitamin C was not associated with lumbar spine bone mass. Further investigation of the role of vitamin C in skeletal health is warranted.

Menopause, menstrual and reproductive history, and bone density in northern Italy

STUDY OBJECTIVE

To analyse the relationship between menstrual and reproductive factors and the risk of low bone mineral density (BMD).

DESIGN

This was a population based screening programme carried out between 1991 and 1993 among 1373 perimenopausal women in northern Italy by means of dual photon absorptiometry at the lumbar spine.

MAIN RESULTS

BMD was strongly related to the age at menopause. In comparison with women reporting menopause below 45 years of age, the odds ratios (OR) of being in the lowest compared with the highest BMD tertile were 0.7 (95% confidence interval (CI) 0.3,1.5) and 0.3 (95% CI 0.1,0.8), respectively, in those with menopause at age 45-49 and above 50 years: the trend in risk was significant. Likewise, the risk of being in the lowest tertile increased with years since the menopause. Compared with women who reported they had undergone the menopause less than two years before interview, the OR of being in the lowest BMD tertile were 2.1 (95% CI 1.1,4.3), 2.3 (95% CI 1.1, 5.0), and 5.7 (95% CI 2.5,12.9) respectively in women who reported menopause 2-5, 6-9, and > or = 10 years earlier. The protective effect on bone density of late age at menopause was observed in different strata of years since menopause. Likewise, the increasing risk of a low BMD with increasing years since the menopause was evident in strata of different age at menopause. No relationships were observed between BMD and the age at menarche, characteristics of menstrual cycles, and the duration of menses. Likewise, no association emerged between reproductive history, including parity and age at first pregnancy, and BMD.

CONCLUSIONS

In this Italian population the risk of being in the lowest BMD tertile decreased with increasing age at menopause and increased with years since menopause. No relationships emerged between BMD and other menstrual characteristics or reproductive factors.

Bone density change and biochemical indices of skeletal turnover

Although biochemical markers of skeletal turnover cannot replace bone density scanning for the diagnosis of osteoporosis, it is thought that they may help add to prediction of fracture risk and help determine adequacy of osteoporosis therapy. Nevertheless, whether biochemical markers in the serum or urine can predict individual rates of bone loss in the spine or hip region is unknown. We studied a heterogeneous group of women (n = 81) who were premenopausal, untreated postmenopausal, and estrogen-treated postmenopausal with baseline determination of body mass index (BMI), calcium intake, biochemical measurements, and serial bone densitometry over 3 years. Serum assays included bone Gla protein (BGP), total and bone-specific alkaline phosphatase (AP, BSAP), carboxyterminal propeptide of type I procollagen (PICP), carboxyterminal telopeptide of type I collagen (ICTP) and tartrate-resistant acid phosphatase (TRAP). Urine assays included hydroxyproline (OHP), calcium, total pyridinoline, and total deoxypyridinoline. Individual biochemical markers and calcium intake were modestly correlated with bone density changes but were inconsistent regarding the spine versus the hip. All of the formation variables were significantly correlated to spine density change (r = -0.24 to -0.49) whereas the only resorption variable that correlated was urine OHp/Cr (r = -0.31). The only formation variable that correlated with hip density change was serum PICP whereas all of the resorption variables except serum TRAP were correlated (r = -0.23 to -0.35). "High turnover" individuals were defined at those with levels of biochemical variables at least 1 SD above the mean young normal for each variable. Higher bone loss rates were seen in this group for several of the turnover markers compared with bone loss rates in all other individuals. However, the sensitivity of this "high turnover" status for identifying high bone losers did not exceed 60% for any of the variables. In untreated postmenopausal women, a model using urine OHp, serum ICTP, serum BSAP, and calcium intake was able to predict 42% of the variance of change in BMD of the lumbar spine. A model using BMI, serum ICTP, and serum BGP could predict 32% of the variance of change in BMD of the femoral neck. No combination of markers could predict variance in bone density change at either site in estrogenized women (premenopausal and estrogen-treated postmenopausal). We conclude that measuring individual serum and urine markers of bone turnover cannot accurately predict bone loss rates in the spine and hip; however, combinations of demographic and biochemical variables could predict some of the variance in untreated postmenopausal women. Biochemical markers cannot replace serial bone densitometry for accurate determination of change in bone mass at the most clinically relevant sites.

Caffeine does not affect the rate of gain in spine bone in young women

The effect of nutrition and dietary caffeine consumption and physical activity on bone gain in women during the third decade of life was determined in a longitudinal, descriptive study of 145 healthy college-aged women. Estimates of caffeine and other dietary intakes were determined by repeated 7-day diet diaries. Measurements of bone mineral in the spine and total body mineral content were determined by dual-photon absorptiometry. Measures of physical activity were ascertained by physical activity monitor. The mean estimated caffeine, calcium and protein intakes for the young women students were 103 +/- 106 mg/day (mean +/- SEM), 831 +/- 334 mg/day (mean +/- SEM) and 66 +/- 16 g/day (mean +/- SEM) respectively. The median rates of bone gain were 5.9% for spine bone mineral content, 6.8% for spine bone mineral density and 12.5% for total body bone mineral. In a multiple regression analysis the significant predictors (+ or -) of the rate of gain were age (-), activity (+), calcium intake (+) and protein intake (-). Caffeine consumption was not associated with significant reduction in rates of bone gain. While calcium and protein nutrition affect bone gain in the third decade of life in women, moderate caffeine intake (one cup of coffee per day, or 103 mg) appears to be safe with respect to bone health in this age group.