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Biomedical subjects

D C Bauer

Publications and source records attributed to D C Bauer.

At least 19 recordsLinked to original sources
PubMed2006

Potential for bone turnover markers to cost-effectively identify and select post-menopausal osteopenic women at high risk of fracture for bisphosphonate therapy.

INTRODUCTION AND HYPOTHESIS: Over half of all fractures among post-menopausal women occur in those who do not have osteoporosis by bone density criteria. Measurement of bone turnover may cost-effectively identify a subset of women with T-score >-2.5 for whom anti-resorptive drug therapy is cost-effective. METHODS: Using a Markov model, we estimated the cost per quality adjusted life year (QALY) for five years of oral bisphosphonate compared to no drug therapy for osteopenic post-menopausal women aged 60 to 80 years with a high (top quartile) or low (bottom 3 quartiles) level of a bone turnover marker. RESULTS: For women with high bone turnover, the cost per QALY gained with alendronate compared to no drug therapy among women aged 70 years with T-scores of -2.0 or -1.5 were $58,000 and $80,000 (U.S. 2004 dollars), respectively. If bisphosphonates therapy also reduced the risk of non-vertebral fractures by 20% among osteopenic women with high bone turnover, then the costs per QALY gained were $34,000 and $50,000 for women age 70 with high bone turnover and T-scores of -2.0 and -1.5, respectively. CONCLUSION: Measurement of bone turnover markers has the potential to identify a subset of post-menopausal women without osteoporosis by bone density criteria for whom bisphosphonate therapy to prevent fracture is cost-effective. The size of that subset highly depends on the assumed efficacy of bisphosphonates for fracture risk reduction among women with both a T-score >-2.5 and high bone turnover and the cost of bisphosphonate treatment.

Administration, Oral↗
PubMed2006

Volumetric and areal bone mineral density measures are associated with cardiovascular disease in older men and women: the health, aging, and body composition study.

The associations of volumetric (vBMD) and areal (aBMD) bone mineral density measures with prevalent cardiovascular disease (CVD) and subclinical peripheral arterial disease (PAD) were investigated in a cohort of older men and women enrolled in the Health, Aging, and Body Composition Study. Participants were 3,075 well-functioning white and black men and women (42% black, 51% women), aged 68-80 years. Total hip, femoral neck, and trochanter aBMD were measured using dual-energy X-ray absorptiometry. Quantitative computed tomography was used to evaluate spine trabecular, integral, and cortical vBMD measures in a subgroup (n = 1,489). Logistic regression was performed to examine associations of BMD measures with CVD and PAD. The prevalence of CVD (defined by coronary heart disease, PAD, cerebrovascular disease, or congestive heart failure) was 29.8%. Among participants without CVD, 10% had subclinical PAD (defined as ankle-arm index <0.9). Spine vBMD measures were inversely associated with CVD in men (odds ratio of integral [OR(integral)] = 1.34, 95% confidence interval [CI] 1.10-1.63; OR(trabecular )= 1.25, 95% CI 1.02-1.53; OR(cortical )= 1.36, 95% CI 1.11-1.65). In women, for each standard deviation decrease in integral vBMD, cortical vBMD, or trochanter aBMD, the odds of CVD were significantly increased by 28%, 27%, and 22%, respectively. Total hip aBMD was associated with subclinical PAD in men (OR = 1.39, 95% CI 1.03-1.84) but not in women. All associations were independent of age and shared risk factors between BMD and CVD and were not influenced by inflammatory cytokines (interleukin-6 and tumor necrosis factors-alpha). In conclusion, our results provide further evidence for an inverse association between BMD and CVD in men and women. Future research should investigate common pathophysiological links for osteoporosis and CVD.

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PubMed2006

Impaired muscle strength is associated with fractures in hemodialysis patients.

INTRODUCTION: Fractures are extremely common among hemodialysis (HD) patients. METHODS: To assess if bone mineral density (BMD) and/or tests of muscle strength were associated with fractures, we studied 37 men and 15 women, 50 years and older, on HD for at least 1 year. We excluded subjects with prior renal transplants and women taking hormone replacement therapy. We inquired about low-trauma fractures since starting dialysis. Subjects underwent BMD testing with a Lunar DPX-L densitometer. Tests of muscle strength included: timed up and go (TUG), 6-min walk, functional reach, and grip strength. Lateral and thoracic radiographs of the spine were obtained and reviewed for prevalent vertebral fractures. We used logistic regression to examine associations between fracture (prevalent vertebral, self-reported low trauma since starting dialysis and/or both) and BMD, and fracture and muscle-strength tests. Analyses were adjusted for age, weight, and gender. RESULTS: Mean age was 66+/-9.0 years, mean weight was 72.9+/-15.2 kg, and most (35 of 52) participants were Caucasian. Average duration of dialysis was 40.2 (interquartile range: 24-61.2) months. The most common cause of renal failure was diabetes (16 subjects). There were no differences by gender or fracture. Of the 52 subjects, 27 had either a vertebral fracture or low trauma fracture. There was no association between fractures, hip or spine BMD, or grip strength. In contrast, greater functional reach [odds ratio (OR) per standard deviation (SD) increase: 0.29; 95% CI: 0.13-0.69), quicker TUG (OR per SD decrease: 0.14; 95% CI: 0.11-0.23), and a greater distance walked in 6 min (OR per SD increase: 0.10; 95% CI: 0.03-0.36) were all associated with a reduced risk of fracture. CONCLUSIONS: Impaired neuromuscular function is associated with fracture in hemodialysis patients.

Absorptiometry, Photon↗
PubMed2006

Classification of osteoarthritis biomarkers: a proposed approach.

OBJECTIVE: Osteoarthritis (OA) biomarkers are needed by researchers and clinicians to assist in disease diagnosis and assessment of disease severity, risk of onset, and progression. As effective agents for OA are developed and tested in clinical studies, biomarkers that reliably mirror or predict the progression or amelioration of OA will also be needed. METHODS: The NIH-funded OA Biomarkers Network is a multidisciplinary group interested in the development and validation of OA biomarkers. This review summarizes our efforts to characterize and classify OA biomarkers. RESULTS: We propose the "BIPED" biomarker classification (which stands for Burden of Disease, Investigative, Prognostic, Efficacy of Intervention and Diagnostic), and offer suggestions on optimal study design and analytic methods for use in OA investigations. CONCLUSION: The BIPED classification provides specific biomarker definitions with the goal of improving our ability to develop and analyze OA biomarkers, and to communicate these advances within a common framework.

Arthrography↗
PubMed2006

Short-term changes in bone turnover markers and bone mineral density response to parathyroid hormone in postmenopausal women with osteoporosis.

CONTEXT: Treatment of osteoporotic women with PTH increases biochemical markers of bone turnover, increases axial bone mineral density (BMD), and reduces fracture risk. OBJECTIVE: Our objective was to determine the relationship between levels of baseline turnover before PTH therapy and short-term changes in turnover during PTH therapy and subsequent changes in areal and volumetric BMD. DESIGN AND SETTING: We conducted a randomized, placebo-controlled trial at four academic centers. PATIENTS: Patients included 238 postmenopausal women with low hip or spine BMD. INTERVENTION: Subjects were randomized to sc PTH (1-84), 100 mug/d (119 women), for 1 yr. MAIN OUTCOME MEASURE: Bone turnover markers were measured in fasting blood samples collected before therapy and after 1 and 3 months. Areal and volumetric BMD at the spine and hip were assessed by dual-energy x-ray absorptiometry and quantitative computed tomography (QCT) after 1 yr of therapy. RESULTS: Among women treated with PTH alone, the relationships between baseline turnover and 1-yr changes in dual-energy x-ray absorptiometry and QCT BMD were inconsistent. Greater 1- and 3-month increases in turnover, particularly the formation marker N-propeptide of type I collagen, were associated with greater increases in areal BMD. When volumetric hip and spine BMD were assessed by QCT, greater short-term increases in turnover were even more positively associated with 1-yr increases in BMD. Each sd increase in the 3-month change of N-propeptide of type I collagen was associated with an a 21% greater increase in QCT spine trabecular BMD. CONCLUSIONS: Greater short-term changes in turnover with PTH therapy are associated with greater 1-yr increases in spine and hip BMD among postmenopausal osteoporotic women.

Absorptiometry, Photon↗
PubMed2006

Case-only analysis of treatment-covariate interactions in clinical trials.

Differential effectiveness of treatments across subgroups defined by pretreatment variables are of increasing interest, particularly in the expanding research field of pharmacogenomics. When the pretreatment variable is difficult to obtain or expensive to measure, but can be assessed at the end of the study using stored samples, nested case-control and case-cohort methods can be used to reduce costs in large efficacy trials with rare outcomes. Case-only methods are even more efficient, and reliable under a range of circumstances.

Alendronate↗
PubMed2005

Inflammatory markers are associated with ventilatory limitation and muscle dysfunction in obstructive lung disease in well functioning elderly subjects.

BACKGROUND: Inflammatory markers are increased in chronic obstructive pulmonary disease (COPD) and are hypothesised to play an important part in muscle dysfunction and exercise intolerance. METHODS: The Health Aging and Body Composition (Health ABC) study is a prospective observational cohort of well functioning individuals aged 70-79 years. A cross sectional analysis of the baseline data was conducted to examine the association between inflammatory markers and ventilatory limitation, muscle strength, and exercise capacity. These associations were compared in participants with and without obstructive lung disease (OLD). RESULTS: Of the 3075 participants enrolled in the Health ABC cohort, OLD was identified by spirometric testing in 268 participants and 2005 participants had normal spirometric results. Of the participants with OLD, 35%, 38%, and 27% participants had mild, moderate, and severe OLD, respectively. Participants with OLD had lower quadriceps strength (102.5 Nm v 108.9 Nm, p = 0.02), lower maximum inspiratory pressure (64.7 cm H(2)O v 74.2 cm H(2)O, p<0.0001), higher systemic interleukin (IL)-6 levels (2.6 pg/ml v 2.2 pg/ml, p<0.0001), and higher C-reactive protein (CRP) levels (3.5 mg/l v 2.5 mg/l, p<0.0001) than those with normal spirometry. In participants with OLD and those with normal spirometry, forced expiratory volume in 1 second (FEV(1)) was associated with IL-6 (adjusted regression coefficients (beta) = -5.3 (95% CI -9.1 to-1.5) and -3.1 (95% CI -4.3 to -1.9), respectively). IL-6 and TNF were also associated with quadriceps strength among participants with OLD and those with normal spirometry (beta = -6.4 (95% CI -12.8 to -0.03) and -3.4 (95% CI -5.4 to -1.3), respectively, for IL-6 and beta = -10.1 (95% CI -18.7 to -1.5) and -3.8 (95% CI -7 to -0.6), respectively, for TNF). IL-6, quadriceps strength, and maximum inspiratory pressures were independent predictors of reduced exercise capacity in both groups. CONCLUSIONS: In well functioning elderly subjects with or without OLD, IL-6 is associated with reduced FEV(1), quadriceps strength, and exercise capacity.

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PubMed2005

Hyperhomocysteinaemia and aortic calcification are associated with fractures in patients on haemodialysis.

BACKGROUND: Fractures and atherosclerosis are common in patients with renal failure; this may be due to hyperhomocysteinemia. AIM: To examine the relationships between fractures, vascular calcification and homocysteine levels in haemodialysis patients. DESIGN: Cross-sectional survey. METHODS: We enrolled 37 men and 15 women who had been on haemodialysis for at least 1 year. We identified prevalent spine fractures by radiographs. Non-spine fractures were identified by self-report and confirmed by review of radiographs or radiology reports. We classified the presence and severity of lumbar aortic calcifications with lateral lumbar radiographs. We measured serum homocysteine in all subjects within 30 days of study entry. RESULTS: After adjusting for age and weight, increased levels of homocysteine were associated with an increased risk fracture (OR per mmol/l increase in homocysteine 1.6, 95%CI 1.2-2.0), as was the presence of aortic calcification (OR 1.6, 95%CI 1.2-2.1). Homocysteine and lumbar aortic calcification were highly correlated (r = 0.86). DISCUSSION: Hyperhomocysteinaemia may explain the relationship between fractures and atherosclerosis in patients with renal failure.

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PubMed2005

Assessment of vertebral fracture using densitometric morphometry.

Diagnosis of vertebral fracture is critical for management of osteoporosis, as existence of such deformities substantially increases the risk of subsequent fracture. Thus, accurate and precise techniques allowing detection of such deformities are essential to clinicians. So far, this detection has been performed by spinal lateral X-rays. More advanced techniques have recently been developed, based on dual energy X-ray absorptiometry (DXA). This review describes these different techniques and discusses the effectiveness of the DXA technique to assess vertebral deformities compared to X-ray. The use of DXA detection of vertebral fracture for clinical practice and clinical trials is discussed. Specifically, vertebral morphometry using DXA provides an excellent specificity, with moderate sensitivity. The major limitation of the DXA vertebral assessment is the poor quality of images of thoracic vertebrae. The clinical utility of vertebral morphometry using densitometry may help screening patients with vertebral fracture, but technological improvements are necessary to improve image quality.

Absorptiometry, Photon↗
PubMed2004

Should age influence the choice of quantitative bone assessment technique in elderly women? The EPIDOS study.

In a prospective cohort of 7,598 women aged 75 and over, we analyzed the effect of age on the ability of femoral neck bone mineral density (BMD) and of ultrasound (BUA and SOS) of the calcaneus to predict hip fracture. Unadjusted regression analysis showed that the risk of hip fracture was increased 1.7 times for one standard deviation increase in age (3.7 years). Overall, for a decrease of one standard deviation in quantitative bone measures, the risk was significantly increased by 2.2 times for BMD (1.9-2.5), 1.8 for BUA (1.6-2.1), and 1.9 for SOS (1.6-2.2). However the average relative risk associated with a decrease in BMD tends to diminish with advancing age, meaning that a smaller part of the risk is explained by BMD in the very elderly. This is confirmed by the areas under the ROC curves (AUC) of BMD that are significantly better before 80 years (0.75 [0.73-0.76]) than after (0.65 [0.63-0.67] in group 80-84 years and 0.65 [0.61-0.68] in group >/=85). On the other hand, as the absolute risk increases exponentially with age, the number of hip fractures attributable to a low BMD is still important in the very elderly, the risk difference between the lowest and the highest quartile of BMD is 25 hip fractures / 1,000 woman-years in the group >/=85 compared with 16 in the two other groups. Thus, after 80, quantitative assessment of bone may still be of interest for clinical decisions. Compared with quantitative ultrasound parameters, the ability of BMD to predict hip fracture was significantly superior to that of BUA and SOS only before the age of 80 (AUC of BMD 0.75 [0.73-0.76], BUA 0.67 [0.66-0.69], SOS 0.67 [0.65-0.69]). For patients older than 80, we did not observe significant differences in AUC between DXA and QUS to predict hip fracture.

Absorptiometry, Photon↗
PubMed2003

HMG CoA reductase inhibitors and the skeleton: a comprehensive review.

Recent studies suggest that the mevalonate pathway plays an important role in skeletal metabolism. HMG CoA reductase inhibitors ("statins"), which inhibit a key enzyme in the mevalonate pathway, are widely used for the treatment of hyperlipidemia. In vitro and animal studies demonstrate that statins stimulate the production of BMP-2, a potent regulator of osteoblast differentiation and activity, suggesting that statins may have an anabolic effect on bone. Statin use in most, but not all observational studies is associated with a reduced risk of fracture, particularly hip fracture, even after adjustment for the confounding effects of age, weight and other medication use. This beneficial effect has not been observed in clinical trials designed to assess cardiovascular endpoints. The effects of statins on bone mass and bone turnover are controversial, but increased bone mass and reduced bone turnover have been observed in controlled studies. Further studies of the skeletal effects of statins are needed, particularly their effects on surrogate markers such as bone mass, bone turnover, and microarchitecture, to determine the optimal formulation, dosing and route of administration. Clinical trials with fracture endpoints are needed before statins can be recommended as therapeutic agents for osteoporosis.

Animals↗
PubMed2003

Incidence and risk factors for a second hip fracture in elderly women. The Study of Osteoporotic Fractures.

Women with hip fracture have an increased risk of second hip fracture but other risk factors for a second hip fracture have not been established. We sought to determine the incidence and risk factors for second hip fracture, in a prospective cohort study of community-dwelling postmenopausal women over 65 years: the Study of Osteoporotic Fractures. From a cohort of 9,704 women, 632 women with a documented first hip fracture during the study were followed up until a second hip fracture or the end of follow-up. Clinical risk factors and bone mineral density were assessed at the beginning of the study. Fifty-three second hip fractures were validated by radiographs. Women with hip fracture had a 2.3% per year risk of second hip fracture. Women who walked for exercise at baseline were less likely to sustain a second hip fracture with a relative risk (RR) of 0.5 [0.3-0.9], as were those who had normal depth perception (RR=0.5 [0.3-0.9]). Women who lost weight since age 25 years had an increased risk of second incident hip fracture (RR = 2.7 [1.6-4.6]), as did those who had a low calcaneal bone mineral density (RR=1.5 [1.1-2.0] per standard deviation decrease in bone mineral density). Current use of estrogen replacement therapy at baseline was protective (RR=0.5 [0.3-0.9]) up to 2 years of follow-up. We conclude that community-dwelling women with a first hip fracture have a high risk of second hip fracture, and risk factors for this second fracture are similar to those of first hip fracture.

Aged↗
PubMed2002

Quantitative ultrasound and mortality: a prospective study.

Previous studies suggest that low bone mineral density (BMD) is associated with increased mortality, but the relationship between quantitative ultrasound (QUS) and mortality is unknown. We studied 5816 women over age 70 years enrolled in the Study of Osteoporotic Fractures. QUS of the calcaneus, and BMD of the calcaneus and hip, were measured at baseline, and women were contacted every 4 months to determine vital status. All reported deaths were confirmed by review of the death certificate or hospital records, and classified by ICD-9 code. During 5.0 years of follow-up, 677 women died. Women in the lowest quintile of QUS had the highest mortality during follow-up. After adjustment for age, grip strength, weight, height, health status, estrogen use, smoking, physical activity, and history of hypertension, diabetes, cardiovascular disease, cancer and stroke, each 1 SD reduction in broadband ultrasonic attenuation (BUA) was associated with a 16% increase in mortality (RH = 1.16; 95% CI: 1.07, 1.26). Mortality from cardiovascular disease, cancer and other causes were all increased among women with low QUS, but the association with cancer deaths was not statistically significant after multiple adjustments (RH = 1.09; CI: 0.93, 1.27). Low BMD was also associated with an increased risk of total and cause-specific mortality, but we found little evidence that BUA and BMD were independent predictors of mortality. Results were similar among women who did not fracture during follow-up. In this large population-based study of older women, low QUS is associated with both total and cause-specific mortality. This relationship was independent of other factors associated with mortality, such as age and health status, and suggests QUS and BMD may reflect some aspect of aging not captured by these traditional factors.

Absorptiometry, Photon↗
PubMed2001

Bone mass and breast cancer risk in older women: differences by stage at diagnosis.

BACKGROUND: Older women with low bone mineral density (BMD) have a decreased incidence of breast cancer. It is not known whether this association is confined to early-stage, slow-growing tumors. METHODS: We prospectively studied 8905 women who were 65 years of age or older during the period from 1986 through 1988 and had no history of breast cancer. At study entry, we used single-photon absorptiometry to measure each woman's BMD at three skeletal sites: the wrist, forearm, and heel. The women were followed for a mean of 6.5 years for the occurrence of breast cancer. All statistical tests were two-sided. RESULTS: During 57 516 person-years of follow-up, 315 women developed primary invasive or in situ breast cancer. Multivariate analyses that adjusted for age, obesity, and other covariates revealed that the risk of breast cancer for women in the highest quartile of BMD for all three skeletal sites was 2.7 (95% confidence interval [CI] = 1.4 to 5.3) times greater than that for women in the lowest quartile at all three skeletal sites. The magnitude of increased risk associated with high BMD differed by the stage of disease at diagnosis and was greater for more advanced tumors (relative risk [RR] for TNM [i.e., tumor-lymph node-metastasis] stage II or higher tumors = 5.6; 95% CI = 1.2 to 27.4) than for early-stage disease (RR for in situ/TNM stage I tumors = 2.2; 95% CI = 1.0 to 4.8). CONCLUSIONS: Elderly women with high BMD have an increased risk of breast cancer, especially advanced cancer, compared with women with low BMD. These findings suggest an association between osteoporosis and invasive breast cancer, two of the most prevalent conditions affecting an older woman's health.

Absorptiometry, Photon↗
PubMed2001

Risk for fracture in women with low serum levels of thyroid-stimulating hormone.

BACKGROUND: Biochemical evidence of hyperthyroidism may be associated with low bone mass, particularly in older postmenopausal women, but no prospective studies of thyroid function and subsequent fracture risk have been done. OBJECTIVE: To examine the association between low levels of thyroid-stimulating hormone (TSH) and fracture in older women. DESIGN: Prospective cohort study with case-cohort sampling. SETTING: Four clinical centers in the United States. PATIENTS: 686 women older than 65 years of age from a cohort of 9704 women recruited from population-based listings between 1986 and 1988. MEASUREMENTS: Baseline assessment of calcaneal bone mass, spine radiography, and history of thyroid disease. Spine radiography was repeated after a mean follow-up of 3.7 years; nonspine fractures were centrally adjudicated. Thyroid-stimulating hormone was measured in sera obtained at baseline from 148 women with new hip fractures, 149 women with new vertebral fractures, and a subsample of 398 women randomly selected from the cohort. RESULTS: After adjustment for age, history of previous hyperthyroidism, self-rated health, and use of estrogen and thyroid hormone, women with a low TSH level (0.1 mU/L) had a threefold increased risk for hip fracture (relative hazard, 3.6 [95% CI, 1.0 to 12.9]) and a fourfold increased risk for vertebral fracture (odds ratio, 4.5 [CI, 1.3 to 15.6]) compared with women who had normal TSH levels (0.5 to 5.5 mU/L). After adjustment for TSH level, a history of hyperthyroidism was associated with a twofold increase in hip fracture (relative hazard, 2.2 [CI, 1.0 to 4.4]), but use of thyroid hormone itself was not associated with increased risk for hip fracture (relative hazard, 0.5 [CI, 0.2 to 1.3]). CONCLUSIONS: Women older than 65 years of age who have low serum TSH levels, indicating physiologic hyperthyroidism, are at increased risk for new hip and vertebral fractures. Use of thyroid hormone itself does not increase risk for fracture if TSH levels are normal.

Aged↗
PubMed2001

Changes in biochemical markers of bone turnover in women treated with raloxifene: influence of regression to the mean.

Measures with extreme magnitude are most likely to be the result of measurement variability. Repeated measurements genuinely lessen such variability, leading to a phenomenon known as regression to the mean (RTM), which may affect biochemical markers of bone turnover. We therefore studied four markers of bone turnover in the Multiple Outcomes of Raloxifene Evaluation (MORE) trial--serum procollagen type I C-propeptide (PICP), osteocalcin (OC), bone-specific alkaline phosphatase (BAP) and urinary type I collagen breakdown product (CTX)--among the 1704 women treated with raloxifene who had marker measurements and were at least 70% adherent, and among 915 control group patients. We examined the existence of RTM, and applied a method of adjustment for RTM of both baseline and follow-up results. We found that women who had the most extreme values tended to go in the opposite direction with the subsequent measurement, i.e., exhibited a pattern of RTM. For example, among women whose urinary CTX decreased at least 60% in the first 6 months, 61% had an increase in the next 6 months; and among those who had an increase in the first 6 months, 81% had a decrease in the next 6 months. We found a similar pattern for each of the four markers. When adjusting for RTM we obtained estimated true values of both baseline values and change in markers. These estimated true values were substantially different from the observed value when the latter was further from the mean. For example, for a 10% increase in urinary CTX in the first 6 months, after accounting for RTM we estimate that there was in fact a 3% decrease (80% confidence interval: -38% to 53%). We conclude that the few initial extreme marker responses observed in women treated with raloxifene represent RTM, and that one practical consequence is that patients with an increase in markers during the first 6 months should be continued on raloxifene therapy, because the values usually decrease later on.

Aged↗
PubMed2001

Association between endogenous hormones and sex hormone-binding globulin and bone turnover in older women: study of osteoporotic fractures.

Estrogen therapy decreases bone remodeling, but the association between endogenous estradiol (E2), estrone (E1), testosterone (T), and bone turnover in older women is not clear. To test the association of serum E2, E1, free T, and sex hormone-binding globulin (SHBG) with bone turnover, we analyzed cross-sectional relationships among E2, E1, T, SHBG, and biochemical markers of bone turnover serum osteocalcin [OC], serum bone-specific alkaline phosphatase [bAP], and serum breakdown products of C telopeptide of type I collagen [CTx] in 704 women enrolled in the Study of Osteoporotic Fractures. Women with lower estradiol levels tended to have higher levels of bone turnover, but the association was weak (R(2) = 0.01 for the association E2-OC, p = 0.03; and R(2) = 0.024 for E2-CTx, p = 0.001). Relationships between SHBG and turnover were also weak (R(2) for the association SHBG-OC was 0.07, p < 0.001, and 0.03 for SHBG-sCTx, p = 0.03), or not significant (R(2) < 0.01 for the association SHBG-bAP). Associations of E1 and T with these markers were of the same magnitude. These results were not modified after adjustment for age, weight, and smoking status. We conclude that older women with low endogenous hormones have somewhat higher bone turnover, but these associations are weak. Bone turnover is determined mainly by factors other than endogenous concentrations of sex hormones.

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