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Biomedical subjects

N H Bjarnason

Publications and source records attributed to N H Bjarnason.

At least 19 recordsLinked to original sources

Optimizing lithium dosing in hemodialysis.

We studied a 62-year-old female hemodialysis patient during initiation and maintenance of lithium carbonate therapy. Three different methods were applied to estimate the regimen: a scenario based on volume of distribution (V(d)), a scenario based on glomerular filtration rate (GFR), and a scenario in which we developed an algorithm based on a 2-compartment distribution without elimination. The GFR estimate led to plasma concentrations 3-4 times lower than those anticipated. In contrast, the estimates based on V(d) and the algorithm derived from pharmacokinetic modeling led to comparable loading dose estimates. Furthermore, the maintenance dose estimated from the central compartment (V1) led to plasma concentrations within the therapeutic range. Thus, a regimen where 12.2 mmol lithium was given after each hemodialysis session resulted in stable between-dialysis plasma lithium concentrations in this patient with no residual kidney function. We did not observe adverse effects related to this regimen, which was monitored from 18 days to 8 months of therapy, and the patient experienced relief from her severe depressive disorder. In conclusion, dialysis patients may be treated with lithium administrated immediately postdialysis. Further observations are necessary to obtain robust long-term safety data and to optimize the monitoring schedule.

Aged↗

Smoking reduces breast tenderness during oral estrogen-progestogen therapy.

OBJECTIVE: We wished to study the influence of smoking upon the occurrence of breast tenderness during oral estrogen-progestogen therapy (EPT). METHODS: Data from 626 healthy postmenopausal women participating in three double-blind, randomized, controlled long-term trials of EPT versus placebo were included. The studies covered sequential, continuous and interrupted regimens of estradiol opposed by a selection of progestins. All studies were mono-center studies and performed in the period 1988-1997. Data on breast tenderness were collected from adverse event reporting and information on smoking status was obtained by interview. RESULTS: Smoking was associated with an earlier age at menopause (difference: 1.3 years, p < 0.001) and a slightly lower body mass index (difference: 0.8 kg/m2, p < 0.01). Smoking women in the EPT groups had significantly lower on-treatment estradiol levels compared to non-smoking women (p < 0.001), whereas no differences were observed in the placebo group. In parallel, the incidence of breast tenderness during EPT was reduced by about one-half (p < 0.001) in smokers compared to non-smokers, whereas no differences were seen on placebo. CONCLUSION: Current smoking reduces the incidence of breast tenderness in women receiving oral EPT. This may be caused by the increased degradation of estradiol during smoking.

Body Mass Index↗

Associated response in bone mineral density and atherogenic lipid profile during treatment with two different selective estrogen receptor modulators: levormeloxifene and raloxifene.

OBJECTIVE: We recently demonstrated a correlation between the responses in two target areas, bone and lipids, during treatment with hormone replacement therapy. Whether the same association exists during treatment with selective estrogen receptor modulators (SERMs) has not been examined before. STUDY DESIGN: This was an exploratory, post hoc analysis of data from two randomized, double-blind, placebo-controlled trials. STUDY POPULATION: From both studies we examined only the Danish subpopulation. Study 1 included 133 women treated with placebo or levormeloxifene in four different doses for 12 months, and study 2 included 248 women treated with raloxifene in three different doses or placebo for 24 months. MEASUREMENTS: Bone mineral density (BMD) of the spine and hip was measured semiannually. Serum lipids and biochemical bone markers were determined at each visit. To eliminate interindividual differences, all values were calculated as individual percentage change from baseline. RESULTS: We found a significant correlation between the increase in BMD of the spine and hip and the decrease in total cholesterol and low-density lipoprotein. CONCLUSION: Our study showed that, in healthy postmenopausal women, the women with the greatest response in BMD were also those with the most favorable response in lipid profile during treatment with SERMs.

Aged↗

Mechanism of circadian variation in bone resorption.

The diurnal variation in bone resorption markers is poorly understood and may contain essential information about regulation of bone resorption. To explore the acute regulation of bone resorption we studied bone turnover in 14 postmenopausal women during a randomized, crossover, 24 h study of oral glucose tolerance test (OGTT), normal diet, or fasting. Whereas fasting counteracted variation in bone resorption, as measured by serum C-telopeptide fragments of collagen type 1 degradation (s-CTx), OGTT and normal diet induced a 50% reduction (p < 0.001) over 2 h. For OGTT, s-CTx reverted to baseline levels after 6 h, and for normal diet s-CTx remained suppressed during the afternoon and returned to baseline overnight. Repeated OGTT at 8:00 A.M. and 8:00 P.M. in nine postmenopausal women demonstrated that identical reductions in s-CTx could be obtained at both timepoints with an intermediate return to baseline between tests. A 2 h randomized, crossover study of OGTT and fasting in 23 men and premenopausal women similarly revealed a 50% decrease in s-CTx. A randomized, crossover 2 h study of insulin tolerance test compared with fasting in six men and premenopausal women demonstrated a 20%-30% decrease in s-CTx (p < 0.01-0.05). Nine hour follow-up of ten healthy individuals during a crossover experiment of OGTT, protein, and fat intake revealed a comparable 50% reduction in s-CTx, but distinct profiles of serum glucose and serum insulin. Bone resorption was reduced by intake of food, glucose, fat, and protein and counteracted by fasting, and this seems to have been be independent of age and gender. Both exogenous and endogenous insulin stimulation tests induced a reduction in bone resorption, but this was only partial when compared with the reduction observed during food intake.

Biomarkers↗

Number of years since menopause: spontaneous bone loss is dependent but response to hormone replacement therapy is independent.

In this study we examine the influence of number of years since menopause on spontaneous bone loss and response to hormone replacement therapy (HRT) in 274 women (56.1 +/- 4.2 years) completing two placebo-controlled HRT studies of 2 or 3 year duration. Both cross sectionally and longitudinally, bone loss in untreated women was greatest closest to menopause and declined thereafter (r = 0.34, p < 0.01 for lumbar spine bone loss and r = 0.25, p < 0.05 for femoral neck bone loss when correlated with number of years since menopause), such that the loss was eliminated in the femoral neck and bone mass increased in the spine in women >10 years after menopause. In contrast, bone turnover was consistently elevated throughout postmenopause, both cross-sectionally and longitudinally. The association with number of years since menopause was counteracted by both 1 and 2 mg estradiol combined with gestodene, piperazine, estrone sulfate in combination with norethisterone, and a combination of 2 mg estradiol and 1 mg norethisterone acetate. In addition, the response to various HRT regimens was independent of baseline bone mass. Whereas bone loss was significantly related to number of years since menopause, all HRT regimens applied arrested bone loss in healthy postmenopausal women, regardless of number of years since menopause.

Age Factors↗

Six and twelve month changes in bone turnover are related to reduction in vertebral fracture risk during 3 years of raloxifene treatment in postmenopausal osteoporosis.

We studied the relationship between change in bone turnover and vertebral fracture risk during raloxifene therapy using 3-year data from the MORE trial, where 2622 of the 7705 randomized women had measurement of bone markers at baseline and after 6 and 12 months participation. Change in bone turnover was significantly related to future risk of vertebral fracture, also after adjusting for baseline vertebral fracture status and BMD. Thus, for a decrease of 9.3 pg/l in serum osteocalcin after 1 year's raloxifene therapy, the odds ratio (OR) for a new vertebral fracture during 3 years was 0.69 (0.54-0.88), p = 0.003. Similarly, for a decrease of 5.91 microg/l in serum bone alkaline phosphatase, OR was 0.75 (0.62-0.92), p = 0.005. The change in BMD over 12 and 24 months was not related to fracture risk in any of the analyses. The strongest predictor for vertebral fracture was prevalent vertebral fracture--even during therapy. The predictive value of baseline BMD was in the same order of magnitude as bone turnover change during raloxifene treatment. In conclusion, the change in bone turnover is related to fracture risk during raloxifene therapy. In contrast the change in BMD is not related to fracture risk. The strongest predictor for vertebral fracture is prevalent vertebral fracture.

Alkaline Phosphatase↗

The effect of fluvastatin on parameters of bone remodeling.

Statins decrease the hepatic biosynthesis of cholesterol, and reduce the incidence of myocardial infarction in women who have already experienced a myocardial infarction. Statins also reduce the risk of atherosclerosis in diabetic patients, but it is unknown whether they influence the glucose tolerance. It has further been suggested that they may influence bone metabolism. Vitamin C is an antioxidant and it decreases serum cholesterol moderately. Antioxidants may also have other metabolic effects, but these are insufficiently studied. The aim of the present study was to investigate the metabolic effects of the cholesterol-lowering agent fluvastatin and the antioxidant vitamin C. Sixty-eight elderly, postmenopausal women with osteoporosis and mild hypercholesterolemia were randomly assigned to 12 weeks open treatment with either fluvastatin (40 mg daily) + 500 mg vitamin C (n = 45) or vitamin C only (n = 23). We measured biochemical markers of bone formation (serum osteocalcin and total alkaline phosphatase) and bone resorption (serum and urinary CTX), parameters related to diabetes and serum lipids and lipoproteins. Fluvastatin in combination with vitamin C had no effect on bone formation markers. We found a weak decrease in parameters of bone resorption, which was significant from baseline, but not different between the two groups. There were no significant effects on any of the other markers of either fluvastatin or vitamin C. The lipid-lowering effect of fluvastatin was confirmed with a decrease of 20% and 30% in serum total cholesterol and LDL-cholesterol, respectively. We conclude that fluvastatin given in clinically relevant doses has no influence on parameters of bone remodeling. Other statins remain to be investigated.

Aged↗

Raloxifene and estrogen reduces progression of advanced atherosclerosis--a study in ovariectomized, cholesterol-fed rabbits.

The present study investigated the effect of raloxifene, a selective estrogen receptor modulator (SERM), on aortic atherosclerosis in 80 ovariectomized, cholesterol-fed rabbits with pre-induced atherosclerosis. The animals were fed an atherogenic diet containing 240 mg cholesterol/day for 15 weeks, after this period a baseline control group was sacrificed. Thereafter, oral treatment was initiated with either estradiol 4 mg/day (n=20), raloxifene (210 mg/day) or placebo (n=20). In the treatment period of 39 weeks, the dietary cholesterol content was reduced to 80 mg cholesterol/day. Postmortem evaluation showed a significantly increased uterine weight induced by estradiol treatment (10.3+/-1.2 g), whereas raloxifene intervention caused a decreased uterus weight (1.21+/-0.1 g) when compared to placebo (2.48+/-0.47 g). Throughout the study, serum lipids increased in all groups to levels seen in very high risk humans. After 58 weeks the cholesterol content in the aorta was 3.18+/-0.54 micromol/cm(2) (38% reduction) in the estradiol group, 3.66+/-0.52 micromol/cm(2) (29% reduction) in the raloxifene group and 5.12+/-0.60 micromol/cm(2) in the placebo group. Analyses of the aortic cholesterol content corrected for time-averaged serum cholesterol revealed that both estradiol and raloxifene therapy significantly reduced the progression of atherosclerosis (P<0.01 for both) as compared to placebo.

Animals↗

How does quantitative ultrasound compare to dual X-ray absorptiometry at various skeletal sites in relation to the WHO diagnosis categories?

The World Health Organisation (WHO) has proposed a set of guidelines for the diagnosis of osteoporosis in adult women based on a measurement of bone mineral density (BMD) expressed as the number of SD below young adult mean (t-score). In this study, we investigated the number of subjects classified as either osteopenic or osteoporotic according to these guidelines using dual X-ray absorptiometry (DXA), at the hip, at the spine and at the lower forearm and quantitative ultrasound (QUS), at the heel. A total of 247 men, 209 postmenopausal women and 195 premenopausal women were included in the study. Furthermore, the study provides the first normative data showing the influence of sex, age and menopause on broadband ultrasound attenuation (BUA) and speed of sound (SOS), as measured by the DTU-one imaging ultrasound scanner. The difference between the number of patients classified into either diagnosis group by the investigated parameters is large ranging from 25.9% of the women being diagnosed as osteopenic by BUA at the heel to 43.0% by BMD at the femoral neck. For men, the same range is from 20.5% by BUA to 44.1% by BMD at the femoral neck. For the classification into the osteoporotic group, the range is from 2.5% by intertrochanteric BMD to 24.4% by BMD at Ward's triangle for women and from 0% by SOS to 29.0% by BMD at Ward's triangle for men. Using total hip BMD as the reference parameter to categorize the subjects as normal, osteopenic or osteoporotic, the agreement of the other parameters with this classification is assessed in terms of sensitivity and specificity. We conclude that there are significant differences in the classification of osteoporosis/osteopenia depending on the site measured and the technique used for the bone mass assessment. Furthermore, we suggest that development of technique and site specific cut-off values may increase the accuracy of the classification of osteoporosis/osteopenia in both men and women.

Absorptiometry, Photon↗

Early response in biochemical markers predicts long-term response in bone mass during hormone replacement therapy in early postmenopausal women.

Based on data from 153 early postmenopausal women who completed a double-blind, randomized 3 year study of graded hormone replacement therapy (HRT) doses or placebo, we investigated the value of bone markers to predict prevention of bone loss. Absolute values of serum and urinary CrossLaps (S-CTX and U-CTX) after 2 weeks of treatment were significantly correlated to 3 year bone mass response (r = -0. 28/-0.35; p < 0.001). These associations were fully expressed at 6 months (r = -0.61/-0.64; p < 0.001). Receiver operating characteristic analyses revealed that the predictive capacity of one measurement of a resorption marker after 6 months' treatment performed similarly as assessment of hip bone mass over 3 years in predicting preservation of spinal bone mass over 3 years. Comparable results were obtained using percent change from baseline in resorption markers at both 6 and 12 months, whereas for formation markers percent change was superior to absolute value at 6 months but not at 12 months. Values of accuracy for S-CTX for a cutoff of 1881 pmol/L at 6 months were 85.2% (sensitivity), 74.3% (specificity), 90.5% (positive predictive value), and 63.4% (negative predictive value); U-CTX performed similarly, whereas the values for the formation markers were slightly lower. A cutoff for S-CTX of 1245 pmol/L eliminated false-positive individuals (those who had a decrease below the cutoff but lost bone). In the false-negative group, which was composed of individuals whose S-CTX did not decrease below the cutoff but had preserved bone mass, S-CTX was significantly associated with spinal bone mass response (r = -0. 41; p < 0.01), indicating these women had been treated with a dose that was not at its optimum for their individual bone turnover. For this cutoff, the values were 49.5% (sensitivity), 97.1% (specificity), 98% (positive predictive value), and 40% (negative predictive value). In conclusion, early bone marker measurements predict long-term preservation of bone mass during HRT. Resorption markers seem superior to formation markers, which reflects that the primary effect of HRT is on bone resorption. A strategy with two cutoff levels may optimize the use of bone markers to predict bone mass response. Whether resorption markers can be used to guide individualized treatment remains to be investigated.

Biomarkers↗

Raloxifene reduces atherosclerosis: studies of optimized raloxifene doses in ovariectomized, cholesterol-fed rabbits.

OBJECTIVE: We have previously shown that raloxifene, a selective oestrogen receptor modulator, 35 mg/day inhibits atherosclerosis in ovariectomized, cholesterol-fed rabbits. This effect was only partial as compared to 17beta-oestradiol 4 mg/day; however, plasma raloxifene concentrations were low relative to those obtained in raloxifene-treated women. We therefore investigate the effects of raloxifene at higher doses. DESIGN: The study on atherosclerosis in ovariectomized, cholesterol-fed rabbits (n = 80) compared raloxifene 70 mg/day and 210 mg/day to 17beta-oestradiol 4 mg/day and placebo. RESULTS: After 48 weeks of therapy, the aortic cholesterol content in the 70 mg/day and 210 mg/day raloxifene treatment groups were 471 +/- 56 nmol/mg protein and 456 +/- 56 nmol/mg protein, respectively. This was significantly less than in the placebo group (654 +/- 69 nmol/mg protein; P < 0.05). In the oestrogen-treated group, the aortic cholesterol content was 357 +/- 62 nmol/mg protein (P < 0.01 as compared to placebo). Differences in serum lipids between the treatment groups could only partly explain the effect on aortic cholesterol content, indicating that additional anti-atherogenic mechanisms may contribute to the decrease in aortic atherosclerosis. This anti-atherosclerotic activity of raloxifene was observed at plasma concentrations comparable to those in postmenopausal women during raloxifene treatment. CONCLUSIONS: We conclude that clinically relevant raloxifene treatment inhibits aortic atherosclerosis in ovariectomized, cholesterol-fed rabbits.

Analysis of Variance↗

Digital X-ray radiogrammetry: a new appendicular bone densitometric method with high precision.

The precision of any given method for measurement of bone mineral density (BMD) is important in relation to the interpretation of repeated measurements over time, e.g. to monitor the course of suspected osteoporosis or follow the effect of therapy. In the present study a new bone densitometer using the digital X-ray radiogrammetry (DXR) method (Pronosco X-posure Systemtrade mark) is investigated with respect to its short-term precision. The study was carried out on two groups of females, one consisting of 20 women between the ages of 30 and 40, and the other of 20 post-menopausal women above the age of 64. The mean age of the premenopausal women was 35.2 years and the mean DXR BMD was 0.578 g cm-2. The mean age of the post-menopausal women was 68.2 years and the mean DXR BMD was 0.489 g cm-2. The short-term precision of the two groups was evaluated using the coefficient of variation (CV%) and corresponding 90% confidence intervals. The coefficient of variation in the premenopausal group was 0.68% with a 90% confidence interval of 0. 57%-0.83%. The coefficient of variation in the postmenopausal group was 0.61% with a 90% confidence interval of 0.52-0.75%. It can be concluded from the present study that the short-term in vivo precision error of the DXR method is low in both pre- and post-menopausal women. When the results of the study are compared to data reported in the literature, the performance of the DXR method seems to be at least equivalent with peripheral DXA.

Adult↗

Low doses of estradiol in combination with gestodene to prevent early postmenopausal bone loss.

OBJECTIVE: Our purpose was to study combinations of estradiol and gestodene for prevention of bone loss in early postmenopausal women. STUDY DESIGN: We randomly assigned 278 healthy, early postmenopausal women to receive either 2 mg 17beta-estradiol sequentially combined with 25 microg gestodene (group 2/25s), 2 mg estradiol sequentially combined with 50 microg gestodene (group 2/50s), 1 mg estradiol sequentially combined with 25 microg gestodene (group 1/25s), 1 mg estradiol continuously combined with 25 mg gestodene (group 1/25c), or placebo. RESULTS: After 3 years the changes in bone mineral density of the spine were as follows (mean +/- SEM): group 2/25s, 7. 41% +/- 0.72%; group 2/50s, 8.53% +/- 0.90%; group 1.25s, 6.67% +/- 0.88%; group 1/25c, 4.44% +/- 0.59%; and placebo group, -2.03% +/- 0. 64%. The changes in bone mineral density were mirrored in the biochemical bone markers. The average responses for the urinary C-terminal telopeptide fragments of type I collagen corrected for creatinine excretion were as follows (mean of baseline +/- SEM): group 2/25s, -68.8% +/- 0.03%; group 2/50s, -72.8% +/- 0.02%; group 1/25s, -60.7% +/- 0.03%; group 1/25c, -52.28% +/- 0.04%; and placebo group, 6.5% +/- 0.09%. Beneficial lipid effects were found in all active groups. The decreases in low-density lipoprotein were as follows (mean +/- SEM): group 2/25s, -13.7% +/- 3.0%; group 2/50s, -14.6% +/- 3.2%; group 1/25s, -9.28% +/- 2.2%; group 1/25c, -9.92% +/- 2.4%; and placebo group, 1.53% +/- 1.9%. CONCLUSION: These results demonstrate that estradiol therapy with 1 mg estradiol is fully protective against early postmenopausal bone loss.

Bone Density↗

The influence of thinness and smoking on bone loss and response to hormone replacement therapy in early postmenopausal women.

We studied the influence of thinness and smoking in 153 early postmenopausal women from a 3-yr period, comparing treatments of 1 or 2 mg estradiol with placebo. The baseline body mass index (BMI) was significantly associated with bone resorption (r = -0.26, P < 0.01 for urinary CrossLaps with 21% difference between extreme tertiles) with a consequent association between BMI and bone mineral density (BMD; r = 0.38, P < 0.001 for BMD of hip with 10% difference between extreme tertiles). A low BMI led to an increased rate of loss (r = 0.45, P < 0.01 for BMD of spine), whereas response to treatment with either 1 or 2 mg estradiol was independent of BMI. Smoking was associated with a 4% lower BMD at baseline compared with that in nonsmokers. This effect was additive with that of BMI. For smokers the increase in serum estradiol during hormone replacement therapy was only half of that in nonsmokers. For women treated with placebo or 2 mg estradiol, serum FSH levels were similar in smokers and nonsmokers, but during treatment with 1 mg estradiol, serum FSH was significantly less suppressed in smokers. This was mirrored in the BMD response, where smokers responded similarly to 2 mg estradiol and placebo as did nonsmokers, whereas smokers receiving 1 mg estradiol experienced only half the increase compared to nonsmokers. In conclusion, thinness and smoking are important risk factors for osteoporosis development, but are counteracted by hormone replacement therapy.

Body Mass Index↗

The effect of raloxifene on risk of breast cancer in postmenopausal women: results from the MORE randomized trial. Multiple Outcomes of Raloxifene Evaluation.

CONTEXT: Raloxifene hydrochloride is a selective estrogen receptor modulator that has antiestrogenic effects on breast and endometrial tissue and estrogenic effects on bone, lipid metabolism, and blood clotting. OBJECTIVE: To determine whether women taking raloxifene have a lower risk of invasive breast cancer. DESIGN AND SETTING: The Multiple Outcomes of Raloxifene Evaluation (MORE), a multicenter, randomized, double-blind trial, in which women taking raloxifene or placebo were followed up for a median of 40 months (SD, 3 years), from 1994 through 1998, at 180 clinical centers composed of community settings and medical practices in 25 countries, mainly in the United States and Europe. PARTICIPANTS: A total of 7705 postmenopausal women, younger than 81 (mean age, 66.5) years, with osteoporosis, defined by the presence of vertebral fractures or a femoral neck or spine T-score of at least 2.5 SDs below the mean for young healthy women. Almost all participants (96%) were white. Women who had a history of breast cancer or who were taking estrogen were excluded. INTERVENTION: Raloxifene, 60 mg, 2 tablets daily; or raloxifene, 60 mg, 1 tablet daily and 1 placebo tablet; or 2 placebo tablets. MAIN OUTCOME MEASURES: New cases of breast cancer, confirmed by histopathology. Transvaginal ultrasonography was used to assess the endometrial effects of raloxifene in 1781 women. Deep vein thrombosis or pulmonary embolism were determined by chart review. RESULTS: Thirteen cases of breast cancer were confirmed among the 5129 women assigned to raloxifene vs 27 among the 2576 women assigned to placebo (relative risk [RR], 0.24; 95% confidence interval [CI], 0.13-0.44; P<.001). To prevent 1 case of breast cancer, 126 women would need to be treated. Raloxifene decreased the risk of estrogen receptor-positive breast cancer by 90% (RR, 0.10; 95% CI, 0.04-0.24), but not estrogen receptor-negative invasive breast cancer (RR, 0.88; 95% CI, 0.26-3.0). Raloxifene increased the risk of venous thromboembolic disease (RR, 3.1; 95% CI, 1.5-6.2), but did not increase the risk of endometrial cancer (RR, 0.8; 95% CI, 0.2-2.7). CONCLUSION: Among postmenopausal women with osteoporosis, the risk of invasive breast cancer was decreased by 76% during 3 years of treatment with raloxifene.

Aged↗

Progestational effects of combinations of gestodene on the postmenopausal endometrium during hormone replacement therapy.

OBJECTIVE: The aim of the study was to assess the dose-response effects on the postmenopausal endometrium of 3 sequential combined hormone replacement regimens and 1 continuous combined hormone replacement regimen of estradiol and gestodene. STUDY DESIGN: In this 2-year double-blind, placebo-controlled study, 278 healthy postmenopausal women received either 2 mg estradiol sequentially combined with 50 microg or 25 microg gestodene, 1 mg estradiol sequentially or continuously combined with 25 microg gestodene, or placebo. RESULTS: All 4 hormone treatment regimens produced a safe endometrial histologic appearance. The regimens that were based on the lower dose of 1 mg estradiol was associated with less uterine bleeding than were those that were based on 2 mg estradiol. For sequentially opposing the 2 mg dose of estradiol, the dose of 25 microg gestodene was less efficient in producing secretory activity than was the dose of 50 microg gestodene. The measurement of placental protein 14 in serum reflected the secretory transformation of the endometrial buildup. CONCLUSION: The reduction in bleeding episodes associated with regimens with lower estradiol doses may lead to improved long-term therapy compliance by menopausal women. The potency of progestogens can be assessed by measuring the serum concentration of placental protein 14.

Dose-Response Relationship, Drug↗

Monitoring of alendronate treatment and prediction of effect on bone mass by biochemical markers in the early postmenopausal intervention cohort study.

To establish whether biochemical markers could be used to monitor alendronate (ALN) treatment and predict long-term response in bone mass, we used results from an ongoing, randomized trial of ALN treatment for prevention of postmenopausal osteoporosis (n = 1202). In women treated with ALN (5 mg), change from baseline at month 6 in urine N-telopeptide cross-links of type I collagen (NTX) and osteocalcin (OC) correlated with change from baseline at month 24 in spine, hip, and total body bone mineral density (BMD) [r = -0.28 to -0.31 (NTX) and r = -0.16 to -0.25 (OC), P<0.001]. This corresponded to a 4- to 5-fold greater increase at month 24 in BMD in the tertiles, with the greatest decrease at month 6 in NTX or OC. In women treated with ALN (5 mg) who had a change at month 24 in spine BMD of at least 0%, 86% (NTX) and 79% (OC) had a decrease at month 6 of at least 40% (NTX) or 20% (OC) (sensitivity). The corresponding specificities were 48% (NTX) and 53% (OC). In conclusion, change at month 6 in NTX and OC, in groups of women treated with ALN, indicated the numeric long-term response in BMD within these groups. In individual women, a decrease at month 6, in NTX or OC below the cut-point, validly identified women who responded, on ALN treatment, with a stabilization or an increase in bone mass. However, lack of decrease below the cut-point in NTX or OC could not be used to identify women with a bone loss during ALN treatment.

Alendronate↗