Deficient production of 1,25-dihydroxyvitamin D in elderly osteoporotic patients

Distinct dietary risk factors for incident osteoporotic fractures in early and late postmenopausal phase women

INTRODUCTION

Available evidence on favorable nutritional factors for preventing osteoporosis remains controversial. Considering the recent increases in life expectancy, we investigated the relationship between incident osteoporotic fractures and dietary habits in early and late postmenopausal phase women.

MATERIALS AND METHODS

Subjects were Japanese postmenopausal outpatients recruited at a primary care institution in Nagano Prefecture (Nagano Cohort Study). Patients with critical or acute illness or secondary osteoporosis were not included in this study. In total, 1,071 participants were prospectively followed for a mean of 5.8 years. The cohort was divided into early (≤ 70 years) and late (> 70 years) postmenopausal phases based on median age. Dietary nutrient intake was estimated by the food frequency questionnaire method. According to baseline nutrient intake characteristics, we focused on protein/energy and Ca/NaCl intake ratios, which were also divided by the median values.

RESULTS

Kaplan-Meier plots revealed a significantly higher occurrence of fractures for the high protein/energy intake group in early postmenopausal subjects (P = 0.009), whereas the low Ca/NaCl intake group in late postmenopausal subjects exhibited a significantly earlier occurrence of fractures (P = 0.002). Multivariate Cox regression uncovered significant independent risks of higher protein/energy (HR 1.35; 95% CI 1.04-1.74) and lower Ca/NaCl (HR 0.79; 95% CI 0.63-0.99) intake ratios for incident osteoporotic fractures in the early and late postmenopausal cohorts, respectively.

CONCLUSION

Distinct dietary risk factors for osteoporotic fractures were identified in early and late postmenopausal phase women. Appropriate nutritional guidance according to patient age will be important for maintaining bone health and quality of life.

Artificial Neural Networks Can Predict Early Failure of Cementless Total Hip Arthroplasty in Patients With Osteoporosis

BACKGROUND

Total hip arthroplasty (THA) done in the aging population is associated with osteoporosis-related complications. The altered bone density in osteoporotic patients is a risk factor for revision surgery. This study aimed to develop and validate machine learning (ML) models to predict revision surgery in patients with osteoporosis after primary noncemented THA.

METHODS

We retrospectively reviewed a consecutive series of 350 patients with osteoporosis (T-score less than or equal to -2.5) who underwent primary noncemented THA at a tertiary referral center. All patients had a minimum 2-year follow-up (range: 2.1 to 5.6). Four ML algorithms were developed to predict the probability of revision surgery, and these were assessed by discrimination, calibration, and decision curve analysis.

RESULTS

The overall incidence of revision surgery was 5.2% at a mean follow-up of 3.7 years after primary noncemented THA in osteoporotic patients. Revision THA was done because of periprosthetic fracture in nine patients (50%), aseptic loosening/subsidence in five patients (28%), periprosthetic joint infection in two patients (11%) and dislocation in two patients (11%). The strongest predictors for revision surgery in patients after primary noncemented THA were female sex, BMI (>35 kg/m2), age (>70 years), American Society of Anesthesiology score (≥3), and T-score. All four ML models demonstrated good model performance across discrimination (AUC range: 0.78 to 0.81), calibration, and decision curve analysis.

CONCLUSION

The ML models presented in this study demonstrated high accuracy for the prediction of revision surgery in osteoporotic patients after primary noncemented THA. The presented ML models have the potential to be used by orthopaedic surgeons for preoperative patient counseling and optimization to improve the outcomes of primary noncemented THA in osteoporotic patients.

Effects of zoledronic acid on bone mineral density around prostheses and bone metabolism markers after primary total hip arthroplasty in females with postmenopausal osteoporosis

INTRODUCTION

To investigate the effect of zoledronic acid on periprosthetic bone mineral density (BMD) and bone metabolism markers after primary total hip arthroplasty in females with postmenopausal osteoporosis.

METHODS

From November 2015 to April 2016, 40 female patients who met the inclusion criteria were randomized into two groups: a control group (calcium + calcitriol) and a zoledronic acid group (calcium + calcitriol + zoledronic acid). At 1 week and 3, 6, and 12 months after operation, BMD was obtained through dual-energy X-ray absorptiometry (DEXA). At pre-operation and at 3, 6, and 12 months after the operation, levels of bone metabolism markers were obtained by serum examination.

RESULTS

Loss of BMD was significantly more pronounced in the control group than in the ZOL group in zones 1, 4, 6, and 7 at 6 months and in zones 1, 2, 4, 6, and 7 at 12 months after the operation. The levels of bone-resorption marker (β-CTX) were significantly lower in the ZOL group than in the control group at 3, 6, and 12 months after operation. The levels of bone-formation marker (TP1NP) performed statistically differences only at 12 months after the operation in these two groups.

CONCLUSIONS

Receiving an intravenous infusion of 5 mg zoledronic acid after THA can effectively reduce periprosthetic BMD loss and improve bone remodeling in females with postmenopausal osteoporosis. Zoledronic acid significantly inhibited bone mass loss in zones 1, 2, 4, 6, and 7 after THA and inhibited bone-resorption marker (β-CTX) to improve bone remodeling. Zoledronic acid treatment is potentially important for patients with osteoporosis after THA.

Soymilk intake has desirable effects on phosphorus and calcium metabolism

The objective was to evaluate the effect of replacing milk with soymilk or calcium-fortified soymilk as a part of a meal on postprandial serum phosphorus levels. This study had a randomized crossover design. Ten healthy subjects were enrolled and consumed three test meals that contained either milk, soymilk, or calcium-fortified soymilk containing the same amount of calcium as milk. Blood samples were collected at 0, 30, 60, 120, 240 and 360 min and urine samples were collected from 0 to 360 min after consuming the test meal. Serum phosphorus levels decreased the most after the ingestion of the soymilk meal, and the least after the ingestion of the milk meal. After the ingestion of each meal, serum intact parathyroid hormone levels showed an initial drop followed by a gradual rise, and these changes were more pronounced for the soymilk meal than for the milk meal and the soymilk + calcium meal. Our study shows that replacing milk with soymilk as a part of a meal may suppress the postprandial elevation in serum phosphorus levels, even when the soymilk contains the same amount of calcium as milk.

Biomarkers of skin aging

Aging is a complex process not only influenced by inherited but also by several environmental factors. It is characterized by a progressive loss of function in multiple tissues, which leads to an increased probability of death. On the other hand, several morphological and histological changes are registered in aged skin that is mostly dependent on the cumulative exposure in environmental aging promoters, such as ultraviolet radiation. Understanding of individual pathogenesis and introduction of preventive measurements require objective assessment, i.e., the administration of biomarkers. Because of the complexity of skin aging, the exact definition of biomarkers is a major research challenge. In this article, we summarize the basic knowledge involving skin aging and its biomarkers.

PTH and Vitamin D

PTH and Vitamin D are two major regulators of mineral metabolism. They play critical roles in the maintenance of calcium and phosphate homeostasis as well as the development and maintenance of bone health. PTH and Vitamin D form a tightly controlled feedback cycle, PTH being a major stimulator of vitamin D synthesis in the kidney while vitamin D exerts negative feedback on PTH secretion. The major function of PTH and major physiologic regulator is circulating ionized calcium. The effects of PTH on gut, kidney, and bone serve to maintain serum calcium within a tight range. PTH has a reciprocal effect on phosphate metabolism. In contrast, vitamin D has a stimulatory effect on both calcium and phosphate homeostasis, playing a key role in providing adequate mineral for normal bone formation. Both hormones act in concert with the more recently discovered FGF23 and klotho, hormones involved predominantly in phosphate metabolism, which also participate in this closely knit feedback circuit. Of great interest are recent studies demonstrating effects of both PTH and vitamin D on the cardiovascular system. Hyperparathyroidism and vitamin D deficiency have been implicated in a variety of cardiovascular disorders including hypertension, atherosclerosis, vascular calcification, and kidney failure. Both hormones have direct effects on the endothelium, heart, and other vascular structures. How these effects of PTH and vitamin D interface with the regulation of bone formation are the subject of intense investigation.

Nocturnal eating disturbs phosphorus excretion in young subjects: a randomized crossover trial

BACKGROUND

Nocturnal eating have recently increased. Serum phosphorus levels and regulators of phosphorus have circadian variations, so it is suggested that the timing of eating may be important in controlling serum phosphorus levels. However, there have been no reports on the effects of nocturnal eating on phosphorus metabolism. The objective was to evaluate the effects of nocturnal eating on phosphorus metabolism.

METHODS

Fourteen healthy men participated in two experimental protocols with differing dinner times. The design of this study was a crossover study. The subjects were served test meals three times (breakfast; 07:30 h, lunch; 12:30 h, dinner; 17:30 or 22:30 h) a day. Blood and urine samples were collected to assess diurnal variation until the following morning.

RESULTS

The following morning, fasting serum phosphorus levels in the late dinner group were markedly higher than those in the early dinner group (p < 0.001), although serum calcium levels were maintained at approximately constant levels throughout the day in both groups. Fluctuations in urinary calcium excretion were synchronized with the timing of dinner eating, however, fluctuations in urinary phosphorus excretion were not synchronized. Urinary phosphorus excretions at night were inhibited in the late dinner group. In the late dinner group, intact parathyroid hormone levels didn't decrease, and they were significantly higher in this group compared with the early dinner group at 20:00 h (p = 0.004). The following morning, fasting serum fibroblast growth factor 23 levels in the late dinner group had not changed, but those in the early dinner group were significantly increased (p = 0.003). Serum free fatty acid levels before dinner were significantly higher in the late dinner group compared with the early dinner group.

CONCLUSIONS

Our results indicate that nocturnal eating inhibits phosphorus excretion. It is suggested that nocturnal eating should be abstained from to manage serum phosphorus levels to within an adequate range.

Histomorphometric bone assessment in patients with fracture of the proximal end of the femur

OBJECTIVE:

To determine whether there is a difference on the bone architecture in patients with femoral neck fracture compared to patients with intertrochanteric fractures and assess the importance of aging on bone microarchitecture in patients with proximal femoral fracture.

METHODS:

Biopsy of the iliac crest was made in seventeen patients between 55 and 90 years old who were admitted to the emergency room with fractures of the proximal end of the femur. After a small fragment was removed, we made a histomorphometric analysis of it.

RESULTS:

There was no significant difference between patients with femoral neck fracture and trochanteric fracture in structural parameters, formation and resorption. Comparing age groups we also did not find any significant change between the groups in the parameters volume and trabecular separation.

CONCLUSION:

There are no difference in the morphometric parameters analyzed between the different types of fracture and age is not a significant factor in the alteration of these parameters.

Level of Evidence II, Diagnostic Studies.

Cross-sectional and longitudinal associations between the active vitamin D metabolite (1,25 dihydroxyvitamin D) and haemoglobin levels in older Australian men: the Concord Health and Ageing in Men Project

Anaemia and low 25 hydroxyvitamin D (25D) and 1,25 dihydroxyvitamin D (1,25D) levels are common in older people and may adversely affect morbidity and mortality. While there is some evidence for an association between low serum 25D levels and anaemia, there are limited studies among community-dwelling older people. In addition, the relationship between anaemia and the active vitamin D metabolite, 1,25D, has not been investigated. The aim of this study was to examine the associations between serum 25D and 1,25D with anaemia in community-living men aged ≥70 years. Population-based, cross-sectional analysis of the baseline phase and longitudinal analysis of the Concord Health and Ageing in Men Project (CHAMP), a large epidemiological study conducted in Sydney among men aged 70 years and older, were performed; 1666 men were seen at baseline (2005-2007), 1314 men at a 2-year follow-up (2007-2009) and 917 at a 5-year follow-up (2012-2013). The main outcome measurement was haemoglobin levels as a continuous measure. Covariates included 25D and 1,25D, estimated glomerular filtration rate, demographic information, lifestyle measures, health conditions and medication information. The prevalence of anaemia (Hb < 13.0 g/dL, WHO definition) was 14.6 %. In cross-sectional analysis, serum 25D concentrations were positively associated with haemoglobin levels in unadjusted analysis (β value 0.004; 95 % confidence interval (CI) 0.0009, 0.007; p = 0.01), but the associations were no longer significant after multivariate adjustment. The association between 1,25D levels and haemoglobin levels was significant in unadjusted analysis (β value 0.003; 95 % CI 0.002, 0.004; p < 0.0001) and remained significant in adjusted analysis (β value 0.001; 95 % CI 0.004, 0.003; p = 0.01). Serum 1,25D (but not 25D) levels at baseline were significantly associated with changes in haemoglobin over 2 and 5 years in unadjusted (β value 0.002; 95 % CI 0.0009, 0.003; p < 0.0001) and in fully adjusted analyses (β value 0.001; 95 % CI 0.0004, 0.002; p = 0.001). Serum 1,25D, but not 25D, concentrations are independently associated with haemoglobin levels in older men in both cross-sectional and longitudinal analyses. This raises the question whether vitamin D metabolites may influence anaemia states, mediated through different biological pathways, or represent a time-dependent biomarker of chronic ill health.

[Assessment of risk factors for fractures in postmenopausal women with osteoporosis]

INTRODUCTION

The main consequence of osteoporosis is bone fracture. Bone fracture risk is determined by several risk factors beyond osteodensitometric results. Some of these factors could be estimated by simple clinical questionnaires.

AIM

The aim of the present study (Score-HU) was to investigate the risk factors of bone fracture among osteoporotic postmenopausal women (n = 11,221), who were examined in an osteologic outpatient departments.

METHOD

Risk factors of each patient were recorded with the use of a simple identical data sheet.

RESULTS

The incidence of risk factors were the following: previous bone fracture (79.4%), medication (except antiporotic treatment, antihypertensive drugs 67.9%, sleeping pills 36%, antidepressants 26.5%, corticosteroids 13.5%), decreased mobility (44.6%), early menopause (31.9%), smoking (31.2%), frequent falls (29.1%), and poor health status (more than 3 chronic diseases; 24.1%).

CONCLUSIONS

Estimating the above mentioned risk factors we could assess the bone fracture risk more accurately than taking alone the bone mineral density results into consideration.

Active vitamin D (1,25 dihydroxyvitamin D) is associated with chronic pain in older Australian men: the Concord Health and Ageing in Men Project

BACKGROUND

Although there is a conflicting evidence for an association between low serum 25-hydroxyvitamin D (25D) levels and pain, the relationship between pain and the active vitamin D metabolite, 1,25-hydroxyvitamin D (1,25D), has not been investigated. The aim of this study was to examine the associations between serum vitamin D metabolites: 25D and 1,25D with intrusive or chronic pain in community-living men aged ≥70 years.

METHODS

Population-based, cross-sectional analysis of the baseline phase of the Concord Health and Ageing in Men Project, a large epidemiological study conducted in Sydney between January 2005 and May 2007. Participants included 1,659 community dwelling men aged ≥70 years, taking part in Concord Health and Ageing in Men Project. Main outcome measurements were symptoms of chronic or intrusive pain. Covariates included 25D and 1,25D, parathyroid hormone, estimated glomerular filtration rate as well as age, country of birth, season of blood collection, body mass index, health conditions, and medication, including nonsteroidal anti-inflammatory drugs and statins.

RESULTS

The prevalence of intrusive pain was 22.9% and of chronic pain was 29.7%. Low serum 25D concentrations were associated with intrusive and chronic pain in unadjusted analysis, but after adjustment, the associations were no longer significant. Low 1,25D levels (<62.0 pmol/L) remained independently associated with chronic pain (odds ratio: 1.53 [1.05, 2.21, p = .02]), even after adjustment for a wide range of potential confounders and covariates of clinical significance.

CONCLUSIONS

Low serum 1,25D concentrations are associated with chronic pain in older men. This raises the question whether vitamin D metabolites may influence pain states, mediated through different biological mechanisms and pathways.

Reduced parathyroid hormone-stimulated 1,25-dihydroxyvitamin d production in vitamin d sufficient postmenoposual women with low bone mass and idiopathic secondary hyperparathyroidism

OBJECTIVE

Distinguishing secondary hyperparathyroidism (sHPT) from eucalcemic primary hyperparathyroidism (EC-pHPT) is important. The objective of this study was to measure parathyroid hormone (PTH)-stimulated production of 1α,25-dihydroxyvitamin D (1,25[OH]2D) in early postmenopausal patients with idiopathic sHPT, who also fit the criteria for EC-pHPT, compared to age-matched controls.

METHODS

In this pilot case-control study, postmenopausal women aged 44 to 55 years with normal serum calcium (Ca), glomerular filtration rate (GFR) ≥65 mL/min, and 25-hydroxyvitamin D (25[OH]D) ≥75 nmol/L (30 ng/mL) were given an 8 hour infusion of PTH(1-34), 12 pmol/kg/h. Patients (n = 5) had elevated PTH, normal 1,25(OH)2D, and no hypercalciuria. Controls (n = 5) had normal PTH. At baseline, 4, and 8 hours, serum Ca, creatinine (Cr), phosphorus (P), 1,25(OH)2D, fibroblast growth factor (FGF23), and 24,25(OH)2D as well as urine Ca, P, Cr, and cAMP/GFR were measured. The fractional excretion of calcium (FeCa) and tubular reabsorption of phosphorus (TMP)/GFR were calculated.

RESULTS

Patients had lower 1,25(OH)2D levels (± SD) than controls at 4 (39.8 ± 6.9 versus 58.8 ± 6.7; P = .002) and 8 hours (56.4 ± 9.2 versus 105 ± 2.3; P = .003) of PTH infusion, attenuated after adjusting for higher body mass index (BMI) in patients (P = .05, .04), respectively. The 24,25(OH)2D levels were lower in patients than controls (1.9 ± 0.6 versus 3.4 ± 0.6, respectively; P = .007). No differences were seen in serum Ca or P, urine cAMP/GFR, TRP/GFR, FeCa, or PTH suppression at 8 hours (patients 50%, controls 64%).

CONCLUSION

Vitamin D sufficient patients who fit the criteria for EC-pHPT had reduced PTH-stimulated 1,25(OH)2D compared to controls, partially attributable to their higher BMI. Other causes of reduced 1,25(OH)2D production ruled out were excessive catabolism of vitamin D metabolites, elevated FGF23, and CYP27B1 mutation. Elevated BMI and idiopathic reduced PTH-stimulated 1,25(OH)2D production should be considered in the differential of sHPT.

Changes in vitamin D metabolites during teriparatide treatment

Parathyroid hormone (PTH) increases the conversion of 25-hydroxyvitamin D [25(OH)D] to 1,25 dihydroxyvitamin D [1,25(OH)(2)D]. The purpose of this study was to assess the changes in serum concentration of vitamin D metabolites 1,25 dihydroxyvitamin D [1,25(OH)(2)D] and 25-hydroxyvitamin D [25(OH)D] during teriparatide 20 μg/day (teriparatide) therapy in the double-blind Fracture Prevention Trial of postmenopausal women with osteoporosis and in the male study of men with osteoporosis. Patients were randomized to teriparatide or placebo and received daily supplements of calcium 1000 mg and vitamin D 400-1200 IU. Serum concentrations of 1,25(OH)(2)D and 25(OH)D were measured. In women (N=336), median 1,25(OH)(2)D concentrations at 1 month increased from baseline by 27% (P<0.0001) in the teriparatide group versus -3% (P=0.87) in the placebo group (between group P<0.0001). At 12 months, the increase was 19% (P<0.0001) in the teriparatide group versus -2% (P=0.23) in the placebo group (P<0.0001). Median 25(OH)D concentrations at 12 months decreased by 19% (P<0.0001) in the teriparatide group versus 0% (P=0.13) in the placebo group (P<0.0001). In men (N=287), median 1,25(OH)(2)D concentrations at 1 month increased by 22% (P<0.0001) in the teriparatide group versus 0% (P=0.99) in the placebo group (P<0.0001). At 12 months, the increase was 14% (P<0.0001) in the teriparatide group versus 5% (P=0.004) in the placebo group (P=0.17). Median 25(OH)D concentrations at 12 months decreased by 11% (P=0.001) in the teriparatide group versus an increase of 1% (P=0.20) in the placebo group (P=0.003). Therefore, treatment with teriparatide increases 1,25(OH)(2)D concentrations and decreases 25(OH)D concentrations.

Primary hyperparathyroidism in older people: surgical treatment with minimally invasive approaches and outcome

Introduction. Elderly patients with primary hyperparathyroidism (pHPT) are often not referred to surgery because of their associated comorbidities that may increase surgical risk. The aim of the study was to review indications and results of minimally invasive approach parathyroidectomy in elderly patients to evaluate its impact on outcome. Materials and Methods. All patients of 70 years of age or older undergoing minimally approach parathyroidectomy at our Department from May 2005 to May 2011 were reviewed. Data collected included patients demographic information, biochemical pathology, time elapsed from pHPT diagnosis to surgical intervention, operative findings, complications, and results of postoperative biochemical studies. Results and Discussion. 37 patients were analysed. The average length of stay was 2.8 days. 11 patients were discharged within 24 hours after their operation. Morbidity included 6 transient symptomatic postoperative hypocalcemias while one patient developed a transient laryngeal nerve palsy. Time elapsed from pHPT diagnosis to first surgical visit evidences that the elderly patients were referred after their disease had progressed. Conclusions. Our data show that minimally invasive approach to parathyroid surgery seems to be safe and curative also in elderly patients with few associated risks because of combination of modern preoperative imaging, advances in surgical technique, and advances in anesthesia care.

A 7-day continuous infusion of PTH or PTHrP suppresses bone formation and uncouples bone turnover

Human in vivo models of primary hyperparathyroidism (HPT), humoral hypercalcemia of malignancy (HHM), or lactational bone mobilization for more than 48 hours have not been described previously. We therefore developed 7-day continuous-infusion models using human parathyroid hormone(1-34) [hPTH(1-34)] and human parathyroid hormone-related protein(1-36) [hPTHrP(1-36)] in healthy human adult volunteers. Study subjects developed sustained mild increases in serum calcium (10.0 mg/dL), with marked suppression of endogenous PTH(1-84). The maximal tolerated infused doses over a 7-day period (2 and 4 pmol/kg/h for PTH and PTHrP, respectively) were far lower than in prior, briefer human studies (8 to 28 pmol/kg/h). In contrast to prior reports using higher PTH and PTHrP doses, both 1,25-dihydroxyvitamin D(3) [1,25(OH)(2) D(3) ] and tubular maximum for phosphorus (TmP/GFR) remained unaltered with these low doses despite achievement of hypercalcemia and hypercalciuria. As expected, bone resorption increased rapidly and reversed promptly with cessation of the infusion. However, in contrast to events in primary HPT, bone formation was suppressed by 30% to 40% for the 7 days of the infusions. With cessation of PTH and PTHrP infusion, bone-formation markers abruptly rebounded upward, confirming that bone formation is suppressed by continuous PTH or PTHrP infusion. These studies demonstrate that continuous exposure of the human skeleton to PTH or PTHrP in vivo recruits and activates the bone-resorption program but causes sustained arrest in the osteoblast maturation program. These events would most closely mimic and model events in HHM. Although not a perfect model for lactation, the increase in resorption and the rebound increase in formation with cessation of the infusions are reminiscent of the maternal skeletal calcium mobilization and reversal that occur following lactation. The findings also highlight similarities and differences between the model and HPT.

Vitamin D, disease and therapeutic opportunities

The discovery of the vitamin D endocrine system and a receptor for the hormonal form, 1α,25-dihydroxyvitamin D(3), has brought a new understanding of the relationship between vitamin D and metabolic bone diseases, and has also established the functions of vitamin D beyond the skeleton. This has ushered in many investigations into the possible roles of vitamin D in autoimmune diseases, cardiovascular disorders, infectious diseases, cancers and granuloma-forming diseases. This article presents an evaluation of the possible roles of vitamin D in these diseases. The potential of vitamin D-based therapies in treating diseases for which the evidence is most compelling is also discussed.

Independent from muscle power and balance performance, a creatinine clearance below 65 ml/min is a significant and independent risk factor for falls and fall-related fractures in elderly men and women diagnosed with osteoporosis

We assessed in a cross-sectional study in elderly men and women with osteoporosis, the association between the creatinine clearance (CrCl) and the performance in different balance and muscle power and function tests and found that a decreasing creatinine clearance was significantly associated with lower balance and muscle power.

INTRODUCTION

To determine if a creatinine clearance of <65 ml/min is significantly associated with decreasing muscle power and balance and an increased risk for falls and fractures.

METHODS

We assessed in a cross-sectional-study in 1781 German osteoporotic patients, the association between the CrCl, the physical performance, and the number of falls and fractures.

RESULTS

Controlling for age, gender, BMI, and osteoporosis treatment (fracture analysis only), a decreasing CrCl was associated with lower physical performance in the timed-up-and-go test (corr -0.2337, P < 0.0001), chair-rising test (corr -0.1706, P < 0.001), and tandem-stand test (corr 0.2193, P < 0.0001), and a CrCl of <65 ml/min was associated with a significantly higher risk for falls (47.7% vs. 36.2%, P = 0.0008) and fall-related fractures (33.1% vs. 22.9%, P = 0.0003) compared with a CrCl of >or=65 ml/min.

CONCLUSIONS

In this study, we found a significant gender-independent correlation between decreasing CrCl and lower performance in balance and muscle power tests. Reduced muscle power and balance may therefore be involved in the low creatinine clearance associated increased risk for falls and fall-related fractures. Furthermore, we found that a CrCl <65 ml/min., independent from the performance in muscle power, muscle function, and balance tests, is a significant risk factor for falls and fractures.

Effects of hPTH(1-34) infusion on circulating serum phosphate, 1,25-dihydroxyvitamin D, and FGF23 levels in healthy men

Fibroblast growth factor 23 (FGF23) promotes phosphaturia and suppresses 1,25-dihydroxyvitamin D [1,25(OH)(2)D] production. PTH also promotes phosphaturia, but, in contrast, stimulates 1,25(OH)(2)D production. The relationship between FGF23 and PTH is unclear, and the acute effect of pharmacologically dosed PTH on FGF23 secretion is unknown. Twenty healthy men were infused with human PTH(1-34) [hPTH(1-34)] at 44 ng/kg/h for 24 h. Compared with baseline, FGF23, 1,25(OH)(2)D, ionized calcium (iCa), and serum N-telopeptide (NTX) increased significantly over the 18-h hPTH(1-34) infusion (p < 0.0001), whereas serum phosphate (PO(4)) transiently increased and then returned to baseline. FGF23 increased from 35 +/- 10 pg/ml at baseline to 53 +/- 20 pg/ml at 18 h (p = 0.0002); 1,25(OH)(2)D increased from 36 +/- 16 pg/ml at baseline to 80 +/- 33 pg/ml at 18 h (p < 0.0001); iCa increased from 1.23 +/- 0.03 mM at baseline to 1.46 +/- 0.05 mM at hour 18 (p < 0.0001); and NTX increased from 17 +/- 4 nM BCE at baseline to 28 +/- 8 nM BCE at peak (p < 0.0001). PO(4) was 3.3 +/- 0.6 mg/dl at baseline, transiently rose to 3.7 +/- 0.4 mg/dl at hour 6 (p = 0.016), and then returned to 3.4 +/- 0.5 mg/dl at hour 12 (p = 0.651). hPTH(1-34) infusion increases endogenous 1,25(OH)(2)D and FGF23 within 18 h in healthy men. Whereas it is possible that the rise in PO(4) contributed to the observed increase in FGF23, the increase in 1,25(OH)(2)D was more substantial and longer sustained than the change in serum phosphate. Given prior data that suggest that neither PTH nor calcium stimulate FGF23 secretion, these data support the assertion that 1,25(OH)(2)D is a potent physiologic stimulator of FGF23 secretion.

Vitamin D across the lifecycle: physiology and biomarkers

The field of vitamin D public health research has a pressing need to define sensitive and specific predictors of vitamin D status that can be used to determine whether an individual or population has a supply of vitamin D that is sufficient to meet requirements. The aim of this review is to highlight the considerations needed when evaluating evidence of the relations between vitamin D biomarkers and functional or health outcomes across the life cycle. It draws attention to the importance of distinguishing between biomarkers of supply, function, and outcome and of considering the many factors that could influence interpretation, such as life stage, ethnicity, body mass index, liver and kidney function, and dietary calcium and phosphorus intake. The vitamin D biomarkers that have shown the most utility to date are the plasma concentration of 25-hydroxyvitamin D (supply), the plasma concentration of parathyroid hormone (function), and the presence or absence of rickets (outcome). However, a single biomarker of vitamin D status or threshold value is unlikely to be valid in all situations. The field therefore needs research to refine existing biomarkers or establish new indicators that take the many factors into account and to identify useful functional biomarkers of vitamin D status for infants, children, women of reproductive age, and specific ethnic groups. However, evidence using the biomarkers currently available shows that frank vitamin D deficiency is a major public health problem in many parts of the world that requires urgent attention.

Hypovitaminosis D and parathyroid hormone response in the elderly: effects on bone turnover and mortality

OBJECTIVE

To investigate whether absence of secondary hyperparathyroidism in the presence of hypovitaminosis D has altered bone turnover, fracture risk and mortality.

DESIGN

A prospective cohort study.

PATIENTS

A total of 1280 older men and women living in residential care facilities.

MEASUREMENTS

We measured baseline serum 25-hydroxyvitamin D (25OHD), serum intact PTH, serum amino-terminal propeptide of type I collagen (PINP) and serum carboxy-terminal telopeptide of type I collagen (CTX-I). Deaths and fractures were recorded prospectively.

RESULTS

Hypovitaminosis D (25OHD < 39 nmol/l) and absence of secondary hyperparathyroidism (PTH > 7.0 pmol/l) in the presence of hypovitaminosis D were common in this sample with a prevalence of 77.5% and 53.3%, respectively. In the presence of hypovitaminosis D, residents showing a hyperparathyroid response (n = 406) had significantly higher serum bone turnover markers than individuals with serum PTH levels < or = 7.0 pmol/l (termed 'low vitamin D, normal PTH', n = 463). After adjusting for risk factors, mortality was significantly higher in the secondary hyperparathyroidism group than in the 'low vitamin D, normal PTH' group [hazard ratio (HR) = 1.35, 95% confidence interval (CI) 1.12-1.64; P = 0.002]. All residents with serum PTH levels < or = 7.0 pmol/l (n = 603) were similar with regard to both bone turnover and mortality, independent of their actual vitamin D status.

CONCLUSION

Absence of secondary hyperparathyroidism in the presence of hypovitaminosis D appears to be common in the frail elderly and is associated with longer survival, similar to that observed in vitamin D-replete elderly subjects.

Vitamin D receptor levels and binding are reduced in aged rat intestinal subcellular fractions

The hormonal form of vitamin D, 1alpha,25(OH)(2)-vitaminD(3) [1alpha,25(OH)(2)D(3)], stimulates signal transduction pathways in intestinal cells. To gain insight into the relative importance of the vitamin D receptor (VDR) in the rapid hormone responses, the amounts and localization of the VDR were evaluated in young (3 months) and aged (24 months) rat intestinal cells. Immune-fluorescence and Western blot studies showed that VDR levels are diminished in aged enterocytes. Confocal microscopy assays revealed that the VDR and other immune-reactive proteins have mitochondrial, membrane, cytosol and perinuclear localization. Western blot analysis using specific antibodies detected the 60 and 50 kDa bands expected for the VDR in the cytosol and microsomes and, to a lesser extent, in the nucleus and mitochondria. Low molecular weight immune-reactive proteins were also detected in young enterocytes subcellular fractions. Since changes in hormone receptor levels appear to constitute a common manifestation of the ageing process, we also analyzed 1alpha,25(OH)(2)D(3) binding properties and VDR levels in subcellular fractions from young and aged rats. In competition binding assays, employing [(3)H]-1alpha,25(OH)(2)D(3) and 1alpha,25(OH)(2)D(3), we have detected specific binding in all subcellular fractions, with maximum binding in mitochondrial and nuclear fractions. Both, VDR protein levels and 1alpha,25(OH)(2)D(3) binding, were diminished with ageing. Age-related declines in VDR may have important consequences for correct receptor/effector coupling in the duodenal tissues and may explain age-related declines in the hormonal regulation of signal transduction pathways that we previously reported.

Osteoporosis

Effective therapies are available for the patient who has arthritic osteoporosis. The approach is critical to ensure an optimal quality of life in these individuals who suffer with a disease that is clearly treatable.

The teriparatide in the treatment of severe senile osteoporosis

The osteoporosis is a systemic disease of multicausal etiopathogenesis. A progressive bone loss and qualitative alterations in the macro- and micro-architecture of the remaining bones, resulting in a loss of strength of bones to such an extent that even very modest traumas will cause fractures characterize it. Three forms are defined (i) postmenopausal appearing after the menopause, (ii) senile appearing with advancing age, and (iii) the idiopathic forms. Severe osteoporosis is declared when the patients suffer vertebral or femoral fractures without any trauma during a treatment with anti-reabsorptive medicines of at least 1-year. The treatment of osteoporosis is based on various categories of pharmaca, such as bisphosphonates, selective estrogen receptor modulators (SERMs), diaminobutyric acid (DABA), parathyroid hormone (PTH), estrogens and non-hormonal drugs. The teriparatide, the recombinant human (rh)PTH(1-34), is identical in amino acid sequence until the 34th (N-terminal) amino acid of the endogenous, human PTH. It is produced in E. coli using the recombinant DNA technology. It is a pharmacon having a strong trophic-anabolic action on the bone tissue, assuring both the inhibition of the bone loss, and the formation of new bones of good quality. It acts as a stimulant of the osteoblast functions, and at the same time, increases the absorption of calcium from the intestine, and also the renal reabsorption of calcium, and decreases the excretion of phosphates in the kidney. This study summarizes our own experience with the use of rhPTH(1-34) in the treatment of senile patients with severe osteoporosis. Our sample consisted of 40 elderly women of the mean age of 78+/-5 years, having severe osteoporosis. They displayed a columnar T-score>-3.5 and femoral T-score>-2.5, had been under antireabsorptive treatment since at least 12 months. In particular, 15 patients were treated with Alendronate (70 mg/week), 10 of them with Risedronate (35 mg/week), and 15 of them with Raloxifene (60 mg/day). These patients in our study were treated for 1 year with 20 microg/day of rhPTH (1-34), injected subcutaneously, and supplemented also with a daily dose of 1g of calcium and 800 IU of Vitamin D, per os. At start of this treatment (time t(0)), after 6 months (time t(6)) and after 12 months (time t(12)) patients underwent a bone mineral density (BMD) analysis (Dexa-Lunar-DPX-P) on the lumbar vertebral column, (L1-L4 zone), as well as a femoral BMD. We applied also quality of life (QoL) questionnaire of the European Foundation for Osteoporosis (QUALEFFO), and evaluated also the use of non-steroidal anti-inflammatory drugs (NSAIDs). Our final considerations are that the teriparatide therapy increases significantly the bone mass density, expressed in terms of T-Score, reduces the occurrence of new fractures, improves the QoL, and decreases also the consumption of NSAIDs.

Molecular backgrounds of age-related osteoporosis from mouse genetics approaches

Backgrounds underlying age-related bone loss can be classified into two categories: systemic abnormality and osteoblast dysfunction. The former includes insufficiency of vitamin D or estrogen, causing a negative balance of calcium metabolism. We propose the contribution of an aging-suppressing gene, klotho, as a novel systemic factor, as a mouse deficient in the klotho gene exhibits multiple aging phenotypes including osteopenia with a low bone turnover. As a factor intrinsic to osteoblasts, we investigated the role of PPARgamma, a key regulator of adipocyte differentiation, based on the facts that osteoblasts and adipocytes share a common progenitor. Heterozygous PPARgamma-deficient mice exhibited high bone mass by stimulating osteoblastogenesis from bone marrow progenitors, and this effect became prominent with aging, indicating involvement of PPARgamma-dependent bone formation in the pathophysiology of age-related bone loss. The local environment of osteoblasts is mainly controlled by cytokines/growth factors, among which insulin-like growth factor-I (IGF-I) is the most possible candidate whose production and activity are decreased with aging. Bone phenotypes of deficient mice of insulin receptor substrates (IRS-1 and IRS-2), essential molecules for intracellular signaling of IGF-I, revealed that IRS-1 is essential to maintain bone turnover by up-regulating anabolic and catabolic functions of osteoblasts, while IRS-2 is needed to keep the predominance of the anabolic function over the catabolic function. A next task ahead of us will be to elucidate the network system of these factors underlying age-related osteoporosis.

High bone turnover is an independent predictor of mortality in the frail elderly

Osteoporotic fractures are associated with accelerated bone turnover and excess mortality. In a prospective study of 1112 frail subjects (79% female; mean age, 86 years), high bone turnover was an independent predictor of all-cause mortality. This association seemed to be mainly manifested in deaths from cardiovascular causes.

INTRODUCTION

Osteoporotic fractures are associated with accelerated bone turnover and excess mortality. In a prospective cohort study of elderly men and women, we assessed whether the rate of bone turnover measured by markers of bone remodeling is a direct predictor of mortality.

MATERIALS AND METHODS

We measured serum concentrations of the aminoterminal propeptide of type I collagen (PINP), a marker of bone formation, and of the carboxyterminal telopeptide of type I collagen (CTX-I), a marker of bone resorption, along with serum PTH and 25-hydroxyvitamin D [25(OH)D] levels in 1112 subjects (79% female; mean age, 86 years) living in residential care. Co-morbidity was measured using the Implicit Illness Severity Scale. Fracture data were validated by a radiology report. Mortality and causes of death were ascertained from death certificates.

RESULTS

Over a median follow-up of 817 days, 559 (50.3%) subjects died. In univariate analyses, time to death from all causes was significantly (p < 0.01) associated with age (HR = 1.62 per 10 years), male sex (HR = 1.33), immobility (HR = 1.94), co-morbidity (HR = 0.31, mild versus severe), lower weight (HR = 0.83 per 10-kg increase), impaired cognitive function (HR = 2.14, severe versus normal), number of medications (HR = 1.05 each), hip fracture (HR = 2.26), log serum creatinine (HR = 1.67), log PTH (HR = 1.29), CTX-I (HR = 1.70, highest 25% versus lowest 75%), and PINP (HR = 1.46, highest 25% versus lowest 75%). In multivariate analysis adjusting for age, sex, immobility, co-morbidity, weight, cognitive function, number of medications, PTH, and hip fracture status, the highest quartile was significantly more likely to die than the rest for both serum CTX-I (HR = 1.39; 95% CI: 1.14-1.70; p = 0.002) and PINP (HR = 1.25; 95% CI: 1.02-1.52; p = 0.03). For individual causes of death, CTX-I was significantly associated with deaths from cardiac causes (HR = 1.78: 95% CI: 1.27-2.50; p < 0.001).

CONCLUSIONS

We conclude that in the frail elderly, high bone turnover is associated with all cause mortality independently of age, sex, health status, serum PTH levels, and hip fracture status. The mechanism of the effect of bone turnover on mortality seems to be mainly manifested in deaths from cardiovascular causes.

[Vitamin D and bone health: is there a need to review supplementation in osteoporosis risk population?]

Vitamin D is an essential hormone for achieving an optimal bone physiology. There is no universal consensus nowadays on the definition of hypovitaminosis D and cut-off values have been refined in the last years. The aim of this review is to analyze vitamin D deficiency among osteoporosis risk populations, including elderly and postmenopausal women, in Spain and other countries. We also review vitamin D supplementation: current clinical guidelines, last clinical studies, safety, and prescription schemes.

Higher 1,25-dihydroxyvitamin D3 concentrations associated with lower fall rates in older community-dwelling women

INTRODUCTION

The purpose of this study was to examine the relationships of vitamin D supplementation and serum concentrations of vitamin D metabolites and parathyroid hormone (PTH) with neuromuscular function and falls in older community-dwelling women.

METHODS

We examined these relationships using a 4-year prospective multi-center study among 9,526 community-dwelling women enrolled in the Study of Osteoporotic Fractures (median age: 70 years; interquartile range: 67-75) and a subset of 389 women (97%) out of 400 who were randomly selected from the entire cohort for serum measures. Measurements included: vitamin D supplementation, serum 25-hydroxyvitamin D(3) [25(OH)D(3)], serum 1,25-dihydroxyvitamin D(3) [1,25(OH) (2)D(3)], and serum intact parathyroid hormone (iPTH); grip and quadriceps strength, chair-stand time, walking speed, reaction time, and balance-walk time (including changes in grip strength, chair-stand time, walking speed and balance-walk time over approximately 3.7 years); and incident fall rates (number of falls/woman-years).

RESULTS

In 9,526 women, vitamin D supplementation was not associated with any measures of neuromuscular function, change in neuromuscular function, or fall rates (p>0.01 for all). In a subgroup of 389 women, there was a trend of higher 25(OH)D(3) concentration with slightly weaker grip strength (p=0.007), and women in the fourth quartile of 1,25(OH)(2)D(3) had a faster chair-stand time (p=0.017) than women in the first quartile; still, in general, concentrations of 25(OH)D(3), 1,25(OH)(2)D(3), and iPTH were not associated with either neuromuscular function or changes in neuromuscular function (p>0.05 for all). However, higher 1,25(OH)(2)D(3) concentration was associated with lower fall rates (p=0.039).

CONCLUSIONS

Higher 1,25(OH)(2)D(3) concentration is associated with a lower fall risk in older community-dwelling women, but vitamin D supplementation, and 25(OH)D(3) and iPTH concentrations are not associated with either neuromuscular function or falls.

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.

The relationship of vitamin D status to bone mineral density in an Italian population of postmenopausal women

Several authors have found a relationship between vitamin D status and bone mineral density (BMD). To our knowledge, no previous studies on this topic have been carried out on the Italian postmenopausal population. We studied this relationship retrospectively in 156 Italian postmenopausal women. We also investigated the relationship between parathyroid hormone (PTH) and BMD. Measurements of BMD were taken at the lumbar spine and upper femur by dual X-ray absorptiometry. Serum 25(OH)D (calcidiol), 1,25(OH)2D (calcitriol), PTH, calcium, phosphorus, creatinine, osteocalcin and urinary calcium and phosphorus were measured according to the current laboratory methods of analysis. We found a positive statistically significant correlation between BMD, both at the spine and hip, and 25(OH)D, and a negative statistically significant correlation between BMD and PTH. No statistically significant correlation was found between BMD and 1,25(OH)2D. Crude logistic regression showed age, 25(OH)D and PTH were significant predictors of low BMD, while 1,25(OH)2D was not. Backward logistic regression showed 25(OH)D was the best predictive model for spine osteoporosis together with age, and on its own it was the best predictive model for femoral neck osteoporosis.

In elderly men and women treated for osteoporosis a low creatinine clearance of <65 ml/min is a risk factor for falls and fractures

Recently, a low creatinine clearance (CrCl) of < 65 ml/min was described as a new significant and independent risk factor for the number of fallers and falls in a community-dwelling elderly population. In this study we investigated if a low creatinine clearance of < 65 ml/min is also a risk factor for falls and fractures in elderly men and women treated for osteoporosis. In a cross-sectional study with the help of questionnaires we assessed the prevalence of having experienced falls within the last 12 months according to renal function in 5,313 German men and women receiving treatment for osteoporosis. The CrCl was calculated using the established Cockcroft-Gault formula. The prevalence of falls and fractures was assessed in multivariate-controlled logistic regression models according to a CrCl cut off of 65 ml/min. The P-values were two-sided. In this study of elderly men and women treated for osteoporosis (n=5,313), 60.9% (n=3,238) had a CrCl of < 65 ml/min, which was associated in multivariate controlled analyses, compared to a CrCl of > or = 65 ml/min (n=2,075), with a significant increased risk of experiencing falls (1,775/3,238 vs. 773/2,075, OR 1.69, 95% CI 1.50-1.91, P<0.0001) and an increased risk for multiple falls (37.1 vs. 22.6%, OR 1.63, 95% CI 1.42-1.87, P<0.0001). Furthermore, compared to a creatinine clearance of > or = 65 ml/min, a creatinine clearance of < 65 ml/min was also associated with a significant increased multivariate controlled risk for hip fractures (OR 1.57, 95%CI 1.18-2.09, P=0.002), for radial fractures (OR 1.79, 95%CI 1.39-2.31, P=<0.0001), for total vertebral fractures (OR 1.31, 95%CI 1.19-1.55, P=0.003) and for fall-associated vertebral fractures (OR 1.24, 95% CI 1.03-1.54, P=0.031). Similar to community-dwelling elderly, in elderly men and women treated for osteoporosis a CrCl of less than 65 ml/min is a significant and independent risk factor for falls. Furthermore, we could show for the first time that a low creatinine clearance in elderly men and women treated for osteoporosis is also associated with a significantly increased risk of vertebral, hip and radial fractures.

Osteoporosis

Bone is a complex organ which contains an organic matrix which serves as scaffolding, includes mineral as calcium distributed in a pattern providing structure and serves as an ion reservoir for the body. Throughout life it dynamically changes in response to changes in activity, body mass, and weight bearing. It is important to define patients at risk for bone loss, since accrued bone loss leading to osteoporosis in the older population of both men and women is unacceptable. There are many different therapies including biphosphonates which can decrease loss of bone and decrease fracture risk in patients who already have had sustained a fracture. Newer therapies such as parathyroid hormone may improve the fracture risk even more than biphosphonates over a shorter period of time.

Vitamin D status as the major factor determining the circulating levels of parathyroid hormone: a study in normal subjects

We investigated the relative contribution of the major factors regulating calcium homeostasis in determining the circulating levels of PTH. We studied 137 males and 125 females who were healthy volunteers. Circulating PTH levels were determined by three different immunoradiometric assays (IRMA). The first one (PTH Sorin, PTH S) utilizes two affinity-purified polyclonal antibodies directed against the 1-34 and 39-84 sequence of the hormone. The two other IRMA share polyclonal anti-PTH (39-84) antibodies. The first assay (PTH Whole, PTH W) utilizes a second polyclonal antibody, directed against the 1-4 amino acid sequence. The second assay (PTH Total, PTH T) utilizes a second antibody specific for the 7-34 region. Concentrations of PTH fragments lacking the initial amino acid sequence (PTH N-truncated, PTH N-t) were determined by the difference of values between PTH T and PTH W. Vitamin D was the main explicative variable almost in every multiple linear regression model, both considering the group as a whole (PTH S: R2 = 0.238, P < 0.0001; PTH W: R2 = 0.08, P < 0.001; PTH T: R2 = 0.145, P < 0.0001; PTH N-t: R2 = 0.081, P < 0.009) and when considering men and women separately. In subjects with vitamin D insufficiency (n = 53) [25(OH)D < 30 nmol/l], mean serum levels of parathyroid hormone were significantly higher (P < 0.001) than those in subjects of similar age with normal vitamin status (n = 209) with all the assays employed. This study demonstrates the central role of 25(OH)D in regulating PTH secretion in physiological conditions.

A new significant and independent risk factor for falls in elderly men and women: a low creatinine clearance of less than 65 ml/min

OBJECTIVES

Because impaired renal function is detrimental for the conversion of calcidiol to calcitriol (D-hormone) and since D-hormone analogues have been shown to decrease the risk of falls, we investigated whether creatinine clearance (CrCl) is associated with the number of fallers and falls in elderly men and women.

METHODS

Within a randomized controlled study, we observed for 36 weeks 186 placebo-treated community-dwelling elderly men and women over 70, in an attempt to determine the influence of baseline CrCl on calcitropic hormone serum levels, as well as the influence of baseline CrCl on the number of fallers and falls over time. With the help of questionnaires, we regularly assessed fall incidence and frequency. The risk of falls and the risk of becoming a faller were assessed in multivariate-controlled logistic regression models according to a cutoff value of the CrCl set at 65 ml/min.

RESULTS

At baseline, serum levels of 1.25(OH)(2)D(3) and iPTH were, in multivariate-controlled analyses, significantly associated with CrCl (p<0.0001, p=0.001, respectively), whereas serum levels of 25(OH)D(3) were not associated with CrCl. Below a CrCl of 65 ml/min, 1.25(OH)(2)D(3) serum levels steadily declined. We therefore chose a CrCl of 65 ml/min as cutoff for further analyses. During the 36 weeks of observation, elderly people with a CrCl of < 65 ml/min had, in multivariate controlled analyses, compared with elderly with a CrCl of > or =65 ml/min, a significantly higher incidence of number of fallers (25/70 vs 21/116; OR=4.01; 95% CI, 1.48-10.98; p=0.006), and a significantly higher incidence of falls (28/70 vs 23/116; OR=3.68; 95% CI, 1.38-9.82; p=0.009).

CONCLUSIONS

For the first time we showed that in a community-dwelling population of elderly men and women, a CrCl of less than 65 ml/min is a significant and independent risk factor for fallers and falls.

Serum parathyroid hormone is associated with increased mortality independent of 25-hydroxy vitamin d status, bone mass, and renal function in the frail and very old: a cohort study

Very frail older people constitute an increasing proportion of the aging population and often have vitamin D deficiency and impaired renal function. Primary hyperparathyroidism has been associated with increased mortality, but it is unclear whether secondary hyperparathyroidism is associated with increased mortality independent of renal function and vitamin D status. This study aimed to examine the effect of vitamin D deficiency and secondary hyperparathyroidism on mortality in frail older people after accounting for renal function and general measures of health. We evaluated 842 subjects (182 men with a mean age of 81.9 yr and 660 women with a mean age of 86.2 yr) living in residential aged care facilities in Sydney, Australia in a prospective, cohort study. Over a mean duration of follow-up of 31 months, 345 subjects died. Baseline serum 25-hydroxy vitamin D, serum PTH, and bone ultrasound attenuation were significantly associated with mortality in univariate and multivariate analyses (for PTH, a hazard ratio of 1.39 for time to death) after correcting for age and gender. In multivariate analyses that corrected for health status, nutritional status, and renal function, PTH remained a significant predictor of mortality but not 25-hydroxy vitamin D or bone ultrasound attenuation. Serum PTH appears to be associated with increased mortality in the frail elderly independent of vitamin D status, renal function, bone mass, and measures of general health. The mechanism of this effect requires further investigation.

Alfacalcidol reduces the number of fallers in a community-dwelling elderly population with a minimum calcium intake of more than 500 mg daily

OBJECTIVES

To study the effect of alfacalcidol (1alpha(OH)D3) on fall risk in community-dwelling elderly men and women.

DESIGN

Randomized, double-blind, placebo-controlled intervention trial.

SETTING

Basel, Switzerland.

PARTICIPANTS

Three hundred seventy-eight community-dwelling elderly (191 women/187 men).

INTERVENTION

Participants were randomly assigned to receive 1 microg of alfacalcidol or matched placebo daily for 36 weeks.

MEASUREMENTS

Serum 25-hydoxyvitamin D3 (25(OH) D,1,25-dihydroxyvitamin D3 (D-hormone), and intact parathormone (iPTH) levels were measured using radioimmunoassay at baseline and every 12 weeks. Numbers of fallers and falls were assessed using a questionnaire during each study site visit. Dietary calcium intake was assessed at baseline using a food frequency questionnaire.

RESULTS

At baseline, participants had, on average, normal vitamin D and D-hormone serum levels. Over 36 weeks, alfacalcidol treatment was associated with fewer fallers (odds ratio (OR)=0.69, 95% confidence interval (CI)=0.41-1.16) than placebo. In a post hoc subgroups analysis by medians of total calcium intake, this reduction reached significance in alfacalcidol-treated subjects with a total calcium intake of more than 512 mg/d (OR=0.45, 95% CI=0.21-0.97, P=.042) but not in those who consumed less than 512 mg/d (OR=1.00, 95% CI= 0.47-2.11, P=.998). Alfacalcidol treatment was also, independent of total calcium intake, associated with a significant 37.9% reduction in iPTH serum levels (P<.0001). No cases of clinically relevant hypercalcemia were observed.

CONCLUSION

Provided a minimal calcium intake of more than 512 mg/d, alfacalcidol treatment significantly and safely reduces number of fallers in an elderly community dwelling population.

Vitamin D and bone health in postmenopausal women

Osteoporosis, a disease of increased skeletal fragility, is becoming increasingly common as the U.S. population ages. Adequate vitamin D and calcium intake is the cornerstone of osteoporosis prevention and treatment. Age-related changes in vitamin D and calcium metabolism increase the risk of vitamin D insufficiency and secondary hyperparathyroidism. Although longitudinal data have suggested a role of vitamin D intake in modulating bone loss in perimenopausal women, studies of vitamin D and calcium supplementation have failed to support a significant effect of vitamin D and calcium during early menopause. There is a clearer benefit in vitamin D and calcium supplementation in older postmenopausal women. Vitamin D intake between 500 and 800 IU daily, with or without calcium supplementation, has been shown to increase bone mineral density (BMD) in women with a mean age of approximately 63 years. In women older than 65, there is even more benefit with vitamin D intakes of between 800 and 900 IU daily and 1200-1300 mg of calcium daily, with increased bone density, decreased bone turnover, and decreased nonvertebral fractures. The decreases in nonvertebral fractures may also be influenced by vitamin D-mediated decreases in body sway and fall risk. There are insufficient available data supporting a benefit from vitamin D supplementation alone, without calcium, to prevent osteoporotic fracture in postmenopausal women.

Rationale for active vitamin D and analogs in the treatment of osteoporosis

In 1981, Chugai Pharmaceutical succeeded in marketing alfacalcidol, a prodrug of calcitriol, as a therapeutic agent for renal osteodystrophy. In 1983, Chugai succeeded in extending the application of alfacalcidol to the treatment of osteoporosis as well. Clinicians in Japan have accepted alfacalcidol as a remedy for osteoporosis. However, the use of calcitriol and its analogs for the treatment of osteoporosis is still controversial. Some misunderstandings exist internationally about the efficacy of the active form of vitamin D for the treatment of osteoporosis. It is important to emphasize that patients with osteoporosis have intestinal calcium malabsorption and dysfunction in renal activation of vitamin D. When massive doses of parent vitamin D were administered to OVX rats, bone mass increased, but surprisingly, many porotic area were observed in the cortical bone. On the other hand, administration of alfacalcidol increased physiological bone without porotic observation. It is necessary to give the active form of vitamin D, D-hormone, with an RDA-equivalent supply of calcium. Alfacalcidol forms physiological strong bones that are hardly fractured by regulating calcium and bone metabolism. We proposed a new vitamin D analog, 2beta (3-hydroxypropoxy)calcitriol [ED-71] as a therapeutic drug for osteoporosis, which is more potent than calcitriol. ED-71 is now being investigated in phase 2 clinical studies in Japan. ED-71 will appear as more improved drugs for osteoporosis until 2010.

Effect of short-chain fructooligosaccharides on intestinal calcium absorption and calcium status in postmenopausal women: a stable-isotope study

BACKGROUND

An enhancing effect of short-chain fructooligosaccharides (scFOSs) on intestinal calcium absorption has been shown in animals and in some short-term human studies. However, the long-term effect of scFOSs on calcium absorption in humans is still unknown.

OBJECTIVE

We investigated the long-term effect of a moderate daily dose (10 g) of scFOSs on intestinal calcium absorption in postmenopausal women.

DESIGN

In a randomized, double-blind crossover protocol, 12 healthy, postmenopausal women received scFOSs or placebo for 5 wk. The treatments were separated by a 3-wk washout period. Subjects orally received (44)Ca (stable isotope) and a fecal marker. Feces were collected after the isotope intake for 5-7 d to measure unabsorbed isotope. Calcium-status indexes, calciotropic hormones, and bone turnover were also assessed.

RESULTS

Mean (+/-SD) intestinal calcium absorption with scFOS treatment was not significantly different from that with placebo treatment (35.63 +/- 9.40% and 36.55 +/- 8.48%, respectively). However, a tendency for calcium absorption to be higher with scFOS treatment than with placebo treatment was observed in women who had been going through menopause for >6 y.

CONCLUSIONS

scFOSs do not modify intestinal calcium absorption in postmenopausal women who do not receive hormonal replacement therapy. The results from a subgroup of women who had been going through menopause for >6 y (n = 6) suggest that scFOSs may influence calcium absorption in the late postmenopausal phase. The small number of subjects and the related P value warrant verification and further investigation with women in late menopause only.

The underuse of therapy in the secondary prevention of hip fractures

There is strong evidence to indicate that individuals who sustain a hip fracture are at a greater risk of developing another. The management of such patients should include efforts to prevent future fractures, including prescribing medications that have been shown to lower hip fracture risk. Such therapies that are currently available include calcium and vitamin D supplementation, alendronic acid and risedronic acid. In addition, there is epidemiological evidence to indicate that estrogen may also decrease the risk of hip fracture. Parathyroid hormone is another agent that has shown promise in this regard and is likely to be available for clinical use in the near future. However, the rates of utilisation of these therapies among patients with hip fractures are low. It is important to emphasise that secondary prevention of hip fractures should be an integral part of the management of individuals who sustain hip fractures.

Effects of vitamin D metabolites on intestinal calcium absorption and bone turnover in elderly women

BACKGROUND

The relative importance of vitamin D metabolites in the regulation of gut calcium absorption has not been well studied in elderly women living in an environment with abundant sunlight.

OBJECTIVE

The objective was to examine the determinants of active gut calcium absorption ( +/- SD: 42 +/- 11%) after an overnight fast with the use of a low (10 mg) calcium load.

DESIGN

One hundred twenty elderly women aged 74.7 +/- 2.6 y underwent an active calcium absorption test with a radioactive calcium tracer, dietary analysis, and measurement of markers of bone turnover and calcium metabolism.

RESULTS

The mean serum 25-hydroxyvitamin D [25(OH)D] concentration at the time of the calcium absorption test was 68 +/- 29 nmol/L. Gut calcium absorption was correlated with 25(OH)D but not 1,25-dihydroxyvitamin D (calcitriol), the free calcitriol index, or dietary calcium intake. After adjustment for age, calcitriol concentration, and dietary calcium intake, the significant determinant of fractional calcium absorption was the 25(OH)D concentration (r = 0.34, P = 0.001). When body weight was included in the regression, both 25(OH)D (beta = 1.20 x 10(-3)) and calcitriol (beta = 1.00 x 10(-3)) were significantly correlated with calcium absorption. Despite the strong relation between 25(OH)D and gut calcium absorption, there was no relation with other aspects of bone turnover or calcium metabolism.

CONCLUSION

These data suggest that at low calcium loads, 25(OH)D is a more important determinant of gut calcium absorption than is calcitriol in elderly women exposed to abundant sunlight, but that this relation has little effect on overall calcium metabolism.

Osteoporosis: pathophysiology and non-pharmacological management

Osteoporosis is the disease of progressive bone loss that is most often associated with ageing and the post-menopausal state in women. All people, men and women, lose bone mass with advancing age, but in some the loss is so great that the skeleton is unable to maintain optimal structural integrity and the result is susceptibility to fractures, particularly of the hip and spine. The condition is increasing dramatically in prevalence as the numbers of elderly in the population increase. In this chapter, the epidemiology, clinical features and current modes of non-pharmacological management of osteoporosis are reviewed, with discussion of the potential of nutraceuticals and functional foods to influence the course of the disease.

Additive effect of alfacalcidol on bone mineral density of the lumbar spine in Taiwanese postmenopausal women treated with hormone replacement therapy and calcium supplementation: a randomized 2-year study

OBJECTIVE

To evaluate the effect of 1alpha-hydroxyvitamin D3 on bone mineral density of the lumbar spine in postmenopausal women receiving hormone replacement therapy and calcium supplement.

DESIGN

A randomized, prospective 2-year clinical trial.

PATIENTS AND MEASUREMENTS

A total of 240 postmenopausal women were enrolled with randomized assignment of 120 patients to each treatment group (the D + E group of 1alpha-hydroxyvitamin D3 + sequential combined HRT + calcium supplement; the E group: sequential combined HRT + calcium supplement). None of the patients had received HRT for menopausal syndrome or osteoporosis before being enrolled in our study. Serum biochemical assays, electrolytes and calcitonin were performed at baseline and after 6 and 12 months of treatment. Bone mineral density (BMD) of L2-L4 was measured by dual energy X-ray absorptiometry (DXA) at the initial assessment and after 12 and 24 months of treatment.

RESULTS

One hundred and five patients (87.5%) in the D + E group and 92 patients (76.7%) in the E group completed the first 1-year study. Ninety-six patients (80%) in the D + E group and 80 patients (66.7%) in the E group completed the 2-year trial. Renal function, liver function, electrolytes and calcitonin showed no significant changes during the first year of follow-up. In the D + E group, the BMD of L2-4 increased 3.24 +/- 0.32% from baseline after 1 year (P < 0.05) and 5.32 +/- 0.23% after 2 years of treatment (P < 0.05). On the other hand, the changes of BMD in the E group were 1.12 +/- 0.34% after 1 year (P < 0.05) and 2.42 +/- 0.26% after 2 years of treatment (P < 0.05). The changes of BMD of L2-L4 of the D + E group were higher than the changes of the E group after both 1 and 2 years of treatment (P < 0.05).

CONCLUSIONS

Our study demonstrated that combination of 1alpha-hydroxyvitamin D3 with HRT is superior to HRT alone for the preservation of bone mineral density in postmenopausal women under calcium supplementation.

Vitamin D deficiency and secondary hyperparathyroidism in the elderly: consequences for bone loss and fractures and therapeutic implications

Vitamin D deficiency is common in the elderly, especially in the housebound and in geriatric patients. The establishment of strict diagnostic criteria is hampered by differences in assay methods for 25-hydroxyvitamin D. The synthesis of vitamin D3 in the skin under influence of UV light decreases with aging due to insufficient sunlight exposure, and a decreased functional capacity of the skin. The diet contains a minor part of the vitamin D requirement. Vitamin D deficiency in the elderly is less common in the United States than elsewhere due to the fortification of milk and use of supplements. Deficiency in vitamin D causes secondary hyperparathyroidism, high bone turnover, bone loss, mineralization defects, and hip and other fractures. Less certain consequences include myopathy and falls. A diet low in calcium may cause an increased turnover of vitamin D metabolites and thereby aggravate vitamin D deficiency. Prevention is feasible by UV light exposure, food fortification, and supplements. Vitamin D3 supplementation causes a decrease of the serum PTH concentration, a decrease of bone turnover, and an increase of bone mineral density. Vitamin D3 and calcium may decrease the incidence of hip and other peripheral fractures in nursing home residents. Vitamin D3 is recommended in housebound elderly, and it may be cost-effective in hip fracture prevention in selected risk groups.