The role of calcium and vitamin D in the management of osteoporosis

Current options for the management of postmenopausal osteoporosis

INTRODUCTION

Osteoporosis is a well-recognized disease with severe consequences if left untreated. The prevention of osteoporosis-associated fractures should include fall prevention, calcium supplementation and life-style advice, as well as pharmacological therapy using agents with proven antifracture efficacy.

AREAS COVERED

This manuscript offers an evidence-based critical assessment of the currently available efficacy data on all new chemical entities that have been granted a marketing authorization for the management of primary osteoporosis in women.

EXPERT OPINION

The availability of new therapeutic agents makes clinical decision making in osteoporosis more complex. Therapeutic decisions should be based on a balance between the benefits and risks of treatment, which must be carefully considered in each particular case, both by the physician and the patient. Indeed, no single agent is appropriate for all patients. Therefore, treatment decisions should be made on a tailor-made basis, taking into account all measures of treatment effect and risk, before making informed judgments about the best individual treatment option.

Maternal vitamin D status affects bone growth in early childhood--a prospective cohort study

In this prospective study, 87 children were followed up from birth to 14 months with data on maternal vitamin D status during the pregnancy. Postnatal vitamin D supplementation improved vitamin D status but only partly eliminated the differences in bone variables induced by maternal vitamin D status during the fetal period.

INTRODUCTION

Intrauterine nutritional deficits may have permanent consequences despite improved nutritional status postnatally. We evaluated the role of prenatal and postnatal vitamin D status on bone parameters in early infancy.

METHODS

Eighty-seven children were followed from birth to 14 months. Background data were collected with a questionnaire and a 3-day food record. At 14 months bone variables were measured with peripheral computed tomography (pQCT) from the left tibia. Serum 25-OHD and bone turnover markers were determined. Findings were compared with maternal vitamin D status during pregnancy.

RESULTS

The children were divided into two groups based on vitamin D status during pregnancy. Despite discrepant S-25-OHD at baseline (median 36.3 vs. 52.5 nmol/l, p < 0.001), the values at 14 months were similar (63 vs. 66 nmol/l, p = 0.58) in Low D and High D. Serum 25-OHD increased more in Low D (p < 0.001) despite similar total intake of vitamin D (mean 12.3 μg/day). In Low D, tibial bone mineral content (BMC) was lower at birth but BMC gain was greater (multivariate analysis of variance [MANOVA]; p = 0.032) resulting in similar BMC at 14 months in the two groups. In High D, tibial total bone cross-sectional area was higher at baseline; the difference persisted at 14 months (MANOVA; p = 0.068). Bone mineral density (BMD) and ΔBMD were similar in the two groups.

CONCLUSIONS

Postnatal vitamin D supplementation improved vitamin D status but only partly eliminated the differences in bone variables induced by maternal vitamin D status during the fetal period. Further attention should be paid to improving vitamin D status during pregnancy.

Extrinsic mechanisms involved in age-related defective bone formation

CONTEXT

Age-related bone loss is associated with progressive changes in bone remodeling characterized by decreased bone formation relative to bone resorption. Both trabecular and periosteal bone formation decline with age in both sexes, which contributes to bone fragility and increased risk of fractures. Studies in rodents and humans revealed that, independent of sex hormone deficiency, the age-related decline in bone formation is characterized by decreased osteoblast number and lifespan and reduced bone-forming capacity of individual osteoblasts. An important clinical question is to identify the mechanisms involved in the age-related defective bone formation.

EVIDENCE ACQUISITION

The mechanisms discussed in this review are based on a PubMed search and knowledge of the authors in the field.

EVIDENCE SYNTHESIS

Available basic and clinical studies indicate that multiple mechanisms are involved in the alterations of osteoblastogenesis and the resulting decline in bone formation with aging. Notably, the age-related osteoblast dysfunctions and defective bone formation are caused by a number of extrinsic clinical factors that inhibit anabolic signaling pathways in bone. Thus, targeting these pathways can abolish age-related bone loss.

CONCLUSIONS

The identification of extrinsic mechanisms involved in osteoblast dysfunctions associated with aging improves our knowledge of age-related bone loss and provides a basis for therapeutic intervention to improve bone formation and bone mass in the aging population.

Relationship between bone mineral density changes and risk of fractures among patients receiving calcium with or without vitamin D supplementation: a meta-regression

Surrogate measures of fracture risk, such as effects on bone mineral density, may be of great interest to assess the efficacy of available osteoporosis treatments.Our results suggest that bone mineral density (BMD)changes cannot be used as a surrogate of anti-fracture efficacy, among patients receiving calcium, with or without vitamin D.

INTRODUCTION

The purpose of this study is to examine the association between changes in bone mineral density with reduction in the risk of fractures in patients receiving calcium with or without vitamin D.

METHODS

We selected all randomized placebo-controlled clinical trials of calcium with or without vitamin D supplementation. To be included in this analysis, the studies were required to report both BMD (hip/proximal femur and/or lumbar spine) and the incidence of fractures. Meta-regression analyses were used to examine the associations of changes in BMD with reduction in risk of fracture over the duration of each study. The change in BMD was the difference between changes (from baseline) observed in the active treatment group and placebo group.

RESULTS

A total of 15 randomized trials (n=47,365) were identified, most of whom (77%) came from the Women's Health Initiative trial. Results show that larger increases in BMD at the lumbar spine were not associated with greater reduction in fracture risk. Concerning hip BMD changes,we found a statistically significant relationship between hip BMD changes and reduction in risk. However, results were not quite significant after excluding the both largest studies, in which BMD changes were measured in very small subset of patients. These points may have largely biased our results.

CONCLUSIONS

In conclusion, there was no evidence of a relationship between BMD changes and reduction in risk of fractures among patients receiving calcium with or without vitamin D supplementation. Calcium and/or Vitamin D may reduce fracture rates through a mechanism independent of bone density.

Screening Filamentous Tropical Fungi for their Nutritional Potential as Sources of Crude Proteins, Lipids and Minerals

The use of fungal and yeast biomass in foodstuff, either as supplements or as major ingredients in formulations is an area of growing interest for the modern food industry. The aim of this study was to evaluate the nutritional potential of biomasses obtained from filamentous fungi Penicillium sclerotiorum, Penicillium janthinellum, Rhizopus stolonifer and Syncephalastrum racemosum. Biomasses presented 26-37% of total proteins, 1.7-3.5% of lipids and 4.6-9.1% of ashes. The humidity level reached 75-83%. Ashes were screened for minerals contents with a special outcome for S. racemosum biomass that presented 3438 mg/100 g (dw) of magnesium. Fatty acids present in the biomasses were screened and the palmitic (C16:0), estearic (C18:0), elaidic (18:1n9-t), oleic (18:1n9-c), linolelaidic (C18:2n6-t), linoleic (C18:2n6-c) and γ-linolenic (C18:3n6) acids were found to be the most abundant, from a total of 88-90% of identified fatty acids. Overall data indicate that the filamentous fungi studied have good nutritional properties, possessing a combination of good level of proteins, low level of fat, and presence of essential fatty acids, including omega-3 derivatives, along with the presence of Ca, Mg, Zn and Fe.

Evidence-based guidelines for the pharmacological treatment of postmenopausal osteoporosis: a consensus document by the Belgian Bone Club

Several drugs are available for the management of postmenopausal osteoporosis. This may, in daily practice, confuse the clinician. This manuscript offers an evidence-based update of previous treatment guidelines, with a critical assessment of the currently available efficacy data on all new chemical entities which were granted a marketing authorization. Osteoporosis is widely recognized as a major public health concern. The availability of new therapeutic agents makes clinical decision-making in osteoporosis more complex. Nation-specific guidelines are needed to take into consideration the specificities of each and every health care environment. The present manuscript is the result of a National Consensus, based on a systematic review and a critical appraisal of the currently available literature. It offers an evidence-based update of previous treatment guidelines, with the aim of providing clinicians with an unbiased assessment of osteoporosis treatment effect.

The role of the orthopaedic surgeon in minimizing mortality and morbidity associated with fragility fractures

Osteoporosis is an underrecognized and undertreated condition associated with fracture. More than 2 million fragility fractures occur each year, almost 300,000 of them hip fractures associated with a threefold risk for future fractures, as well as a 15% to 33% mortality rate within the first year of fracture. Orthopaedic surgeons can facilitate osteoporosis treatment by coordinating care for patients with fragility fractures by managing the current fracture, evaluating risk factors for osteoporosis, and, for hospitalized patients, developing a follow-up plan that notes whether the patient should be further evaluated or treated for osteoporosis. For the patient seen in the office, evaluation for osteoporosis should be performed and, if indicated, treatment should be undertaken. When osteoporosis treatment is warranted, diphosphonates are the standard of care, and administration of zoledronic acid once yearly has been proven to reduce the risk of subsequent fractures after low-energy hip fracture. By following these steps, orthopaedic surgeons can help ensure that patients with fragility fractures receive appropriate osteoporotic treatment, thereby reducing the risk of subsequent fractures.

The effects of a 30-month dietary intervention on bone mineral density: The Postmenopausal Health Study

Low dietary Ca intake and vitamin D insufficiency have been implicated as part of the aetiology leading to osteoporosis. The aim of the present study was to examine the effects of a 30-month dietary intervention that combined supplementation of dairy products fortified with Ca and vitamin D3 and lifestyle and nutrition counselling sessions on bone mineral density (BMD) of postmenopausal women. Sixty-six postmenopausal women (aged 55–65 years) were randomised into a dietary group (DG; n 35), receiving daily and for the first 12 months 1200 mg Ca and 7·5 μg vitamin D3, while for the next 18 months of intervention 1200 mg Ca and 22·5 μg vitamin D3 through fortified dairy products, and a control group (CG; n 31) receiving neither counselling nor dairy products. The DG was found to have more favourable changes in arms (P < 0·001), total spine (P = 0·001) and total body BMD (P < 0·001) compared with the CG. Furthermore, a significant increase was observed for the DG in lumbar spine BMD (0·056; 95 % CI 0·009, 0·103), which was not found to differentiate significantly compared with the change observed in the CG (P = 0·075). In conclusion, the present study showed that intakes of vitamin D of about 22·5 μg/d and of Ca close to the recommended level of 1200 mg from fortified dairy foods for 30 months, with compliance ensured by lifestyle and nutrition counselling sessions, can induce favourable changes in arms, total spine and total body BMD of postmenopausal women.

Bone mineralization defects and vitamin D deficiency: histomorphometric analysis of iliac crest bone biopsies and circulating 25-hydroxyvitamin D in 675 patients

Parathyroid hormone (PTH) is only one measurable index of skeletal health, and we reasoned that a histomorphometric analysis of iliac crest biopsies would be another and even more direct approach to assess bone health and address the required minimum 25-Hydroxyvitamin D [25(OH)D] level. A cohort from the northern European population with its known high prevalence of vitamin D deficiency therefore would be ideal to answer the latter question. We examined 675 iliac crest biopsies from male and female individuals, excluding all patients who showed any signs of secondary bone diseases at autopsy. Structural histomorphometric parameters, including osteoid indices, were quantified using the Osteomeasure System according to ASBMR standards, and serum 25(OH)D levels were measured for all patients. Statistical analysis was performed by Student's t test. The histologic results demonstrate an unexpected high prevalence of mineralization defects, that is, a pathologic increase in osteoid. Indeed, 36.15% of the analyzed patients presented with an osteoid surface per bone surface (OS/BS) of more than 20%. Based on the most conservative threshold that defines osteomalacia at the histomorphometric level with a pathologic increase in osteoid volume per bone volume (OV/BV) greater than 2% manifest mineralization defects were present in 25.63% of the patients. The latter were found independent of bone volume per trabecular volume (BV/TV) throughout all ages and affected both sexes equally. While we could not establish a minimum 25(OH)D level that was inevitably associated with mineralization defects, we did not find pathologic accumulation of osteoid in any patient with circulating 25(OH)D above 75 nmol/L. Our data demonstrate that pathologic mineralization defects of bone occur in patients with a serum 25(OH)D below 75 nmol/L and strongly argue that in conjunction with a sufficient calcium intake, the dose of vitamin D supplementation should ensure that circulating levels of 25(OH)D reach this minimum threshold (75 nmol/L or 30 ng/mL) to maintain skeletal health.

Supplementation with bio-calcium from shells Pinctada maxima in postmenopausal women with decreased mineral bone density--pilot study

INTRODUCTION

Treatment of osteoporosis, in addition to a specific antiresorptive or anabolic treatment, requires supplementation with calcium and vitamin D. Widespread cultivation of pearl shells has made pearls available for commercial use for a very reasonable price. The main chemical compound of pearls from shells Pinctada maxima is calcium-carbonate (CaCO3). Recently developed technologies applied in a micronisation process have provided increased gastrointestinal resorption of calcium, estimated at over 90% of calcium intake.

OBJECTIVE

The paper is aimed at monitoring of efficacy and tolerance of six-month bio-calcium supplementation in postmenopausal women with reduced bone mineral density.

METHODS

Group 1 (30 patients) received, three times a day, capsules of pearl powder from shells Pinctada maxima (it is equal to 260 mg of elementary calcium); group II (20 patients) received a daily dose of 500 mg inorganic CaCO3. Both groups received 666 IU of cholecalciferol per day. In all patients, bone mineral density (BMD) of the spine or hip, serum blood and urine levels of Ca, phosphates and alkaline phosphatase, were measured before and after six months of the treatment.

RESULTS

Group I/Group II: average age 61.7/61.7 years; beginning of menopause: 48.32 /48 years; menopause duration 13.4/13.7 years; average body mass index 27.2/27 kg/m2. These two groups did not different significantly before supplementation. Six-month supplementation with CaCO3 of the biological origin led to the increase of BMD from 0.901 g/cm2 to 0.948 g/cm2 (p = 0.067), while BMD remained the same in the group supplemented with inorganic CaCO3 Gastrointestinal tolerability of bio-calcium was excellent, without any adverse events.

CONCLUSION

These data could not strongly support the hypothesis of better efficacy of bio-calcium taking into account a small number of patients and a short follow-up period in this pilot study. Tolerance of CaCO3 of the biological origin was excellent and free of any adverse events. The results of laboratory values were within normal range.

Determinant factors of osteoporosis patients' reported therapeutic adherence to calcium and/or vitamin D supplements: a cross-sectional, observational study of postmenopausal women

BACKGROUND

Among the various treatments for osteoporosis, calcium and/or vitamin D supplements are frequently included.

OBJECTIVE

The objective of the study was to analyse adherence to calcium and/or vitamin D treatment and to identify related predictors of non-adherence in a sample of postmenopausal women treated for osteoporosis in primary care.

METHODS

A cross-sectional, observational study was conducted in a sample of postmenopausal women receiving pharmaceutical treatment for osteoporosis with vitamin D and/or calcium. Sociodemographic, general and osteoporosis-related data were collected. Patient's perceptions of the adverse effects of treatment, their knowledge of osteoporosis (Batalla test), their attitude towards treatment (Morisky-Green test) and their self-reported therapeutic adherence (Haynes-Sackett test) were assessed.

RESULTS

Of 630 women (mean age +/- SD 64.1 +/- 8.7 years) evaluated, 36.2% (95% CI 32.4, 39.9) had problems with treatment tolerability, 63.5% (95% CI 59.7, 67.3) had good knowledge of osteoporosis, 20.5% (95% CI 17.3, 23.6) had a good attitude to treatment and 50.0% (95% CI 46.1, 53.9) had good self-reported adherence to treatment. Patients in the poor adherence group had higher mean body mass index (p = 0.014), more concurrent pathologies (p = 0.003), more tolerability problems (p < 0.001) and worse attitude to treatment (p < 0.001). The multivariate model showed a positive relationship between therapeutic adherence and good attitude to treatment (odds ratio [OR] = 11.7; p < 0.001), not having tolerability problems (OR = 3.3; p < 0.001) and no polymedication (OR = 0.80; p = 0.017).

CONCLUSIONS

Only one in two postmenopausal women with osteoporosis who take calcium and/or vitamin D have good self-reported therapeutic adherence to this treatment. Determinant factors of adherence to calcium and/or vitamin D treatment were patient's attitude to the treatment, tolerability problems with the treatment and number of concurrent treatments.

Updated fracture incidence rates for the US version of FRAX

On the basis of updated fracture and mortality data, we recommend that the base population values used in the US version of FRAX be revised. The impact of suggested changes is likely to be a lowering of 10-year fracture probabilities.

INTRODUCTION

Evaluation of results produced by the US version of FRAX indicates that this tool overestimates the likelihood of major osteoporotic fracture. In an attempt to correct this, we updated underlying fracture and mortality rates for the model.

METHODS

We used US hospital discharge data from 2006 to calculate annual age- and sex-specific hip fracture rates and age-specific ratios to estimate clinical vertebral fracture rates. To estimate the incidence of any one of four major osteoporotic fractures, we first summed these newly derived hip and vertebral fracture estimates with Olmsted County, MN, wrist and upper humerus fracture rates, and then applied 10-20% discounts for overlap.

RESULTS

Compared with rates used in the current FRAX tool, 2006 hip fracture rates are about 16% lower, with greatest reductions observed among those below age 65 years; major osteoporotic fracture rates are about one quarter lower, with similar reductions across all ages.

CONCLUSIONS

We recommend revising the US-FRAX by updating current base population values for hip fracture and major osteoporotic fracture. The impact of these revisions on FRAX is likely to be lowering of 10-year fracture probabilities, but more precise estimates of the impact of these changes will be available after these new rates are incorporated into the FRAX tool.

Management of osteoporosis in the elderly

BACKGROUND

Osteoporosis is predominantly a condition of the elderly, and the median age for hip fracture in women is approximately 83 years. Osteoporotic fracture risk is multifactorial, and often involves the balance between bone strength and propensity for falling.

OBJECTIVE

To present an overview of the available evidence, located primarily by Medline searches up to April, 2009, for the different management strategies aimed at reducing the risk of falls and osteoporotic fractures in the elderly.

RESULTS

Frailty is an independent predictor of falls, hip fractures, hospitalisation, disability and death in the elderly that is receiving increasing attention. Non-pharmacological strategies to reduce fall risk can prevent osteoporotic fractures. Exercise programmes, especially those involving high doses of exercise and incorporating balance training, have been shown to be effective. Many older people, especially the very elderly and those living in care institutions, have vitamin D inadequacy. In appropriate patients and given in sufficient doses, vitamin D and calcium supplementation is effective in reducing both falls and osteoporotic fractures, including hip fractures. Specific anti-osteoporosis drugs are underused, even in those most at risk of osteoporotic fracture. The evidence base for the efficacy of most such drugs in the elderly is incomplete, particularly with regard to nonvertebral and hip fractures. The evidence base is perhaps most complete for the relatively recently introduced drug, strontium ranelate. Non-adherence to treatment is a substantial problem, and may be exacerbated by the requirements for safe oral administration of bisphosphonates.

CONCLUSION

Evidence-based strategies are available for reducing osteoporotic fracture risk in the elderly, and include exercise training, vitamin D and calcium supplementation, and use of evidence-based anti-osteoporotic drugs. A positive and determined approach to optimising the use of such strategies could reduce the burden of osteoporotic fractures in this high-risk group.

Vitamin D status and common risk factors for bone fragility as determinants of quantitative ultrasound variables in a nationally representative population sample

Calcaneal quantitative ultrasound (QUS) can predict bone strength and fracture risk. Bone fragility has no single cause but results from a complex interplay of several etiologic or contributing factors. Vitamin D is essential for bone health even though it is still unclear how much of this vitamin is required to maintain bone strength and prevent fractures. Measurements of serum 25-hydroxyvitamin D [S-25(OH)D] have indicated a high prevalence of inadequate vitamin D status in a number of studies mostly based on selected study populations. The objective of this study was to examine the associations between S-25(OH)D, common risk factors for bone fragility, and QUS variables in a large unselected population sample. The study population consisted of 2736 men and 3299 women from a nationally representative population sample, aged 30 years or over. Information on lifestyle was elicited by means of interviews and questionnaires. Body fat mass was estimated using an impedance-meter. S-25(OH)D was measured by radioimmunoassay. Calcaneal QUS was performed on the Hologic Sahara apparatus recording broadband ultrasound attenuation (BUA) and speed of sound (SOS). The potential determinants of BUA and SOS were analysed using separate multiple linear regression models for men and women. S-25(OH)D proved to be an independent determinant of BUA (P<0.0001 for men, P<0.001 for women) and SOS (P<0.0001 for men, P<0.05 for women). BUA was also independently associated with age, height, weight, alcohol consumption, and postmenopausal status in women, and with weight, alcohol consumption, smoking and physical activity in men. All of the above variables, except for weight in women, were also found to be independent determinants of SOS in both men and women. A reverse association was found between S-25(OH)D and adiposity in spite of higher intakes of vitamin D in those with higher fat mass. In this unselected sample of men and women, vitamin D status, several lifestyle factors and physical characteristics proved to be significant determinants of BUA and SOS. Inadequate vitamin D status was common, and measures ensuring adequate intakes of vitamin D in the population thus deserve continued attention. Obesity should be taken into account in future assessments of vitamin D status in Finland as in other countries.

Osteomalacia and vitamin D deficiency in a psychiatric rehabilitation unit: case report and survey

Background

Vitamin D deficiency is common and predisposes to many serious diseases, yet often goes unrecognized.

Findings

We describe a case of severe vitamin D deficiency with osteomalacia in a patient resident in a psychiatric hospital for more than 35 years, and discuss causes and complications. We assayed the serum 25-hydroxyvitamin D levels of all patients under our care on one old-age psychiatry rehabilitation unit. Ten of twelve (83%) of patients had vitamin D deficiency, and 92% had suboptimal vitamin D levels. Vitamin D status was strongly predicted by dietary supplementation. Of those not on vitamin D supplements, 100% had vitamin D deficiency, with vitamin D levels significantly below those of historical controls. Age, sex, and duration of admission did not predict vitamin D status in this group.

Conclusion

We advocate vitamin D screening in all patients admitted to psychogeriatric units, and discuss treatment options given the current problems affecting high-dose vitamin D supply to the United Kingdom.

Highest prevalence of vitamin D inadequacy in institutionalized women compared with noninstitutionalized women: a case-control study

The reduced capacity of older skin to synthesize vitamin D(3) under the influence of ultraviolet light makes older persons at risk of vitamin D deficiency. The risk could even be increased in institutionalized persons owing to their lower sunshine exposure. It has been reported that an inadequate vitamin D level is associated with secondary hyperparathyroidism, increased bone turnover, and bone loss, which increase fracture risk. The objective of this study was to assess the prevalence of inadequate serum vitamin D levels in institutionalized, postmenopausal, osteoporotic women. Assessment of 25-hydroxyvitamin D [25(OH)D] was performed in 445 institutionalized, osteoporotic women from nine countries (Australia, Belgium, France, Germany, Hungary, Italy, Poland, Spain and UK). For each institutionalized woman, three age-matched, noninstitutionalized, osteoporotic controls were also included. Four cutoffs of 25(OH)D inadequacy were fixed: less than 80, less than 75, less than 50 and less than 30 nmol/l. Mean age was 79.7 years (standard deviation [SD] = 5.8) for the institutionalized women and 79.5 years (SD = 5.5) for the noninstitutionalized women (p = 0.45). Significantly fewer institutionalized women received vitamin D supplements (13.2 vs 24.0%; p < 0.0001). In women without vitamin D supplements, the level of 25(OH)D was significantly lower in institutionalized women (56.9 [SD = 23.9] nmol/l) compared with noninstitutionalized women (63.2 [SD = 22.0] nmol/l; p < 0.0001). In institutionalized women (without vitamin D supplements), the prevalence of 25(OH)D inadequacy was 10.4, 41.2, 80.3 and 84.2% when considering cutoffs of 80, 75, 50 and 30 nmol/l, respectively. In the control group, the prevalence was 2.7, 22.9, 74.4 and 81.7%, respectively. The prevalence of vitamin D inadequacy was significantly higher in institutionalized women when considering the 75, 50 and 30 nmol/l cutoffs but not when considering the 80 nmol/l cutoff. This study highlights a high prevalence of vitamin D inadequacy in institutionalized, osteoporotic women. Compared with age-matched osteoporotic controls, the prevalence of severe vitamin D inadequacy was substantially more important in institutionalized women. We believe that a greater awareness of the importance of vitamin D inadequacy is needed in order to address this public health problem.

Vitamin D status and response to antiosteoporotic therapy

Evaluation of: Adami S, Giannini S, Bianchi G et al.: Vitamin D status and response to treatment in post-menopausal osteoporosis. Osteoporos. Int. (2008) (Epub ahead of print). All recent osteoporosis guidelines recommend that patients taking treatments for osteoporosis (i.e., bisphosphonates) should be supplemented with vitamin D and calcium. However, the bone response (i.e., bone mineral density change and fractures incidence) to bisphosphonates therapy in relation to vitamin D intake in clinical practice is unknown. In a recent retrospective study, 1515 women with postmenopausal osteoporosis under antiresorptive treatment were classified as vitamin D deficient or vitamin D repleted, according to risk factors or the level of 25 hydroxy vitamin D above or below 50 nmol/l. The change in bone mineral density remained significantly higher in vitamin D-repleted compared with vitamin D-deficient women. Moreover, the adjusted odds ratio for incident fractures in vitamin D-deficient as compared with vitamin D-repleted women was 1.77 (95% CI: 1.20-2.59; p = 0.004).

Vitamin D: current status and perspectives

The role of vitamin D in maintaining bone health has been known for decades. Recently, however, the discovery that many tissues expressed the vitamin D receptor and were able to transform the 25-OH vitamin D into its most active metabolite, 1,25-(OH)

Clin Chem Lab Med 2009;47:120–7.

Bone parameters are improved with intermittent dosing of vitamin D3 and calcitonin

Intermittent combination of an anabolic agent to promote bone formation and an antiresorptive agent that would prevent further bone loss is a theoretically attractive approach for restoring bone mass. We tested the potential of intermittently dosed calcitriol and calcitonin (CT) to restore bone properties in ovariectomized (Ovx) rats. Rats had Ovx or sham surgery at 8 weeks old and 4 weeks later were assigned to experimental groups: (1) sham vehicle, (2) Ovx vehicle, (3) Ovx + parathyroid hormone (PTH, 40 microg/kg), and (4) Ovx + calcitriol (2 microg/kg) + CT (2 microg/kg). Group 3 received PTH every week throughout the study, and group 4 received calcitriol at weeks 1, 3, 5, and 7 and CT at weeks 2, 4, 6, and 8. Dosing was carried out for 8 weeks with serum, and micro-computed tomographic analysis was done at 0, 4, and 8 weeks. Femurs and tibias were used for radiological analyses and for mechanical testing. Dosing with PTH improved bone mass and structure of cancellous bone at metaphyses of tibias and femurs as well as properties of cortical bone including geometry and strength. Intermittent dosing with calcitriol and CT was less potent in correcting loss of cancellous bone relative to treatment with PTH and had no effect on cortical bone parameters. However, intermittent dosing with calcitriol and CT was robust enough to improve cancellous bone mass and structure through bone formation without causing deleterious side effects. Our data provide additional evidence that therapies can be devised to ameliorate the skeletal defects associated with established osteoporosis.

Comparison of native or reformulated chicory fructans, or non-purified chicory, on rat cecal fermentation and mineral metabolism

Chicory inulin has been identified as an effective prebiotic to promote active fermentation and lactobacilli proliferation in the large intestine, and to enhance calcium (Ca) digestive absorption and deposition in bones. The aim of this study was to compare, in a growing rat model, the effects on digestive fermentations and mineral metabolism of diets containing 7.5% inulin, using either a purified native inulin ((NAT)Inulin) or a reformulated inulin ((REF)Inulin, based on a combination of short- and long chain fructans) or dehydrated chicory. All the inulin diets elicited a marked enlargement of the cecum and acidification of the cecal contents (P < 0.01) and these diets promoted succinic acid rich fermentation together with substantial amounts of short-chain fatty acids (SCFA), especially butyrate. After 1 month of adaptation, all the inulin diets strongly enhanced Ca absorption compared to controls (P < 0.01), but this effect was no more observed after 3 months of adaptation. Magnesium (Mg) absorption was stimulated by the inulin diets after 1 and 3 months experiment. Bone parameters were significantly affected by the chicory diet (enhanced distal bone mineral density and breaking load) whereas the purified inulin diets were less effective. In conclusion, with the present model, both (NAT)Inulin and (REF)Inulin exerted similar effects as to (1) cecal fermentation and profile of end-products of bacterial metabolism, (2) stimulation of Ca and Mg digestive absorption and (3) overall effects on bone parameters. The particular effects of the chicory crude fractions on digestive fermentation and bone parameters suggest possible synergisms between inulin-type fructans and other nutrients.