Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis

[Treatment of osteoporosis in the elderly: what is the evidence?]

Many older people, especially women, and their doctors still see osteoporosis as part of the natural course of ageing instead of as a preventable or treatable disorder. Height loss, hyperkyphosis, back pain, and fractures are accepted as consequences of ageing. The notion that it is too late to start treatment in a late stage of the disease forms another barrier to treatment. Although most studies of fracture reduction with medical treatment were not designed for the "geriatric" population, the average age of participants in most clinical trials was about 70 years. In all major studies patients also received calcium and vitamin D supplements. Nowadays, clinicians can choose from several effective treatments for the prevention of osteoporotic fractures in high-risk postmenopausal women. Data on the anti-fracture potential of calcium/vitamin D, raloxifene, bisphosphonates, strontium ralenate, and parathyroid hormone are now available. Bisphosphonates and strontium ralenate are good choices for first- or second-line treatment, while for the time being parathyroid hormone should only be used for the second-line treatment of osteoporosis in the elderly.

Vitamin D and human health: lessons from vitamin D receptor null mice

The vitamin D endocrine system is essential for calcium and bone homeostasis. The precise mode of action and the full spectrum of activities of the vitamin D hormone, 1,25-dihydroxyvitamin D [1,25-(OH)(2)D], can now be better evaluated by critical analysis of mice with engineered deletion of the vitamin D receptor (VDR). Absence of a functional VDR or the key activating enzyme, 25-OHD-1alpha-hydroxylase (CYP27B1), in mice creates a bone and growth plate phenotype that mimics humans with the same congenital disease or severe vitamin D deficiency. The intestine is the key target for the VDR because high calcium intake, or selective VDR rescue in the intestine, restores a normal bone and growth plate phenotype. The VDR is nearly ubiquitously expressed, and almost all cells respond to 1,25-(OH)(2)D exposure; about 3% of the mouse or human genome is regulated, directly and/or indirectly, by the vitamin D endocrine system, suggesting a more widespread function. VDR-deficient mice, but not vitamin D- or 1alpha-hydroxylase-deficient mice, and man develop total alopecia, indicating that the function of the VDR and its ligand is not fully overlapping. The immune system of VDR- or vitamin D-deficient mice is grossly normal but shows increased sensitivity to autoimmune diseases such as inflammatory bowel disease or type 1 diabetes after exposure to predisposing factors. VDR-deficient mice do not have a spontaneous increase in cancer but are more prone to oncogene- or chemocarcinogen-induced tumors. They also develop high renin hypertension, cardiac hypertrophy, and increased thrombogenicity. Vitamin D deficiency in humans is associated with increased prevalence of diseases, as predicted by the VDR null phenotype. Prospective vitamin D supplementation studies with multiple noncalcemic endpoints are needed to define the benefits of an optimal vitamin D status.

Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment

Throughout the life cycle the skeleton requires optimum development and maintenance of its integrity to prevent fracture. Bones break because the loads placed on them exceed the ability of the bone to absorb the energy involved. It is now estimated that one in three women and one in twelve men aged >55 years will suffer from osteoporosis in their lifetime and at a cost in the UK of > 1.7 pounds x 10(9) per year. The pathogenesis of osteoporosis is multifactorial. Both the development of peak bone mass and the rate of bone loss are determined by key endogenous and exogenous factors. Ca supplements appear to be effective in reducing bone loss in women late post menopause (>5 years post menopause), particularly in those with low habitual Ca intake (<400 mg/d). In women early post menopause (<5 years post menopause) who are not vitamin D deficient, Ca supplementation has little effect on bone mineral density. However, supplementation with vitamin D and Ca has been shown to reduce fracture rates in the institutionalised elderly, but there remains controversy as to whether supplementation is effective in reducing fracture in free-living populations. Re-defining vitamin D requirements in the UK is needed since there is evidence of extensive hypovitaminosis D in the UK. Low vitamin D status is associated with an increased risk of falling and a variety of other health outcomes and is an area that requires urgent attention. The role of other micronutrients on bone remains to be fully defined, although there are promising data in the literature for a clear link between vitamin K nutrition and skeletal integrity, including fracture reduction.

Osteoporosis and vertebral compression fractures-continued missed opportunities

BACKGROUND CONTEXT

Untreated osteoporosis causes decreased bone mineral density, which predisposes to fragility fractures. Low-energy vertebral compression fractures are the most common type of osteoporotic fragility fracture. Prior studies have shown that only one-quarter of patients diagnosed with an osteoporotic fracture are referred or treated for osteoporosis.

PURPOSE

To identify the rate of therapeutic interventions for patients aged 50 years and older within a capitated population who sustained low impact vertebral compression fractures over a 6-month period.

STUDY DESIGN/SETTING

Retrospective observational study.

PATIENT SAMPLE

The reports of all imaging studies of the chest, abdomen, and spine taken from July to December 2002 within a large military health-care system were queried on the Composite Health Computer System (CHCS). The sample included patients 50 years or older who had a low-energy vertebral compression fracture.

OUTCOME MEASURES

The computerized medical records were examined for osteoporotic medication prescriptions, referrals to endocrinology, and to dual-energy X-ray absorptiometry (DEXA) scans. These results were compared with results obtained from a similar study on osteoporotic distal radius fractures.

RESULTS

The records of 156 patients (average age: 77.3y; 78 women, 78 men) meeting the inclusion criteria were analyzed to determine what proportion was followed-up with osteoporosis interventions. Within 1 year after the fracture, 39% (37 females, 24 males) had undergone a DEXA scan, 35% (37 females, 18 males) had been referred to endocrinology, 38% (47 females, 12 males) were receiving active osteoporosis treatment, and 51% (55 females, 25 males) were receiving any form of osteoporosis-directed medication. The rate of medical intervention was similar to the rate of intervention after distal radius fragility fractures (n=111; 30% active medication; 47% any osteoporosis medication) (p>.21). The rate of all interventions was significantly greater for women than men.

CONCLUSIONS

Although the likelihood of intervention is slightly greater after vertebral compression fractures than for distal radius fractures, orthopedic surgeons, emergency room physicians, and primary care providers continue to miss opportunities, especially in males, to diagnose and/or initiate active therapeutic interventions for osteoporosis in patients presenting with osteoporosis-related fragility fractures.

Dietary supplement use among elderly, long-term cancer survivors

INTRODUCTION

The purpose of the present study was to assess dietary supplement use and its association with micronutrient intakes and diet quality among older (>or=65 years), long-term survivors (>or=5 years post-diagnosis) of female breast, prostate, and colorectal cancer.

METHODS

The sample included 753 survivors who participated in telephone screening interviews to determine eligibility for a randomized diet and physical activity intervention trial entitled RENEW: Reach-out to ENhancE Wellness in Older Cancer Survivors. Telephone surveys included two 24-hour dietary recalls and items regarding supplement use (type, dose, and duration). Nutrient intakes were compared to Dietary Reference Intakes (DRIs). Diet quality was assessed using the revised Healthy Eating Index (HEI). Descriptive statistics and multivariate logistic regression were used in this cross-sectional study.

RESULTS

A majority of survivors (74%) reported taking supplements, with multivitamins (60%), calcium/vitamin D (37%), and antioxidants (30%) as the most prevalent. Overall proportions of the total sample with dietary intakes below Estimated Average Requirements (EARs) were substantial, although supplement users had more favorable mean HEI scores (P < 0.01) and nutrient intakes for 12 of the 13 vitamins and minerals investigated (P values < 0.05). Supplement use was positively associated with older age (>or=70 years) (odds ratio (OR)=1.70; 95% confidence interval (95% CI)=1.17, 2.46) and female gender (OR=1.49; 95% CI=1.04, 2.13), and negatively associated with current smoking (OR=0.40, 95% CI=0.21, 0.76). Individuals scoring higher on the Total Fruit (OR=1.12, 95% CI=1.01, 1.23), Whole Grain (OR=1.14, 95% CI=1.04, 1.25), and Oil (OR=1.10, 95% CI=1.01, 1.11) components of the HEI were significantly more likely to take supplements, while those scoring higher on the Meat and Beans category (OR=0.81, 95% CI=0.71, 0.93) were significantly less likely to take supplements. Compared to those with less than a high school education, survivors with a professional or graduate degree were significantly more likely to use supplements (OR=2.18, 95% CI=1.13, 4.23).

DISCUSSIONS/CONCLUSIONS

Demographic, disease, and health-related correlates of supplement use follow similar trends observed in the general population as well as previous reports from other cancer survivor populations. Supplement use may reduce the prevalence of nutrient inadequacies in this population, though survivors who use supplements are the least likely to need them.

IMPLICATIONS FOR CANCER SURVIVORS

Supplement use may be an effective means for many survivors to achieve adequate nutrient intakes; however, open communication between healthcare providers and survivors is needed to ensure potential concerns are addressed as supplement use may not always be beneficial.

The diagnosis and treatment of primary osteoporosis according to current guidelines

INTRODUCTION

Osteoporosis is the most common generalized disease of the skeleton, yet it is markedly undertreated in Germany.

METHODS

Selective literature review on the basis of the current German guidelines regarding the prevention, diagnosis, and treatment of osteoporosis in postmenopausal women and in men aged 60 and above, and a further search of literature published in the last three years.

RESULTS AND DISCUSSION

The indication for dual X-ray absorptiometry (DXA) measurement for the specific diagnosis of osteoporosis is derived from the patient's age, sex, history of fractures in the past, and further risk factors. The therapeutic threshold for osteoporosis has been set at a 30% predicted risk of osteoporotic fractures occurring within 10 years. The treatment consists of basic measures for fracture prevention combined with specific pharmacotherapy. The recommended drugs for the treatment of osteoporosis in postmenopausal women in particular are alendronic and ibandronic acid, raloxifen, risedronic acid, and strontium ranelate; the only approved drugs for men at present are alendronic and risedronic acid and teriparatid. Intensive patient education markedly improves the otherwise poor compliance with osteoporosis treatment.

Short and long-term variations in serum calciotropic hormones after a single very large dose of ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) in the elderly

CONTEXT

In humans, few studies have compared the potencies of ergocalciferol and cholecalciferol in improving and maintaining vitamin D status.

OBJECTIVE

Our objective was to evaluate the effects of a single very large dose of both calciferols on serum changes of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], ionized calcium, and parathyroid hormone (PTH) at baseline, and at 3, 7, 30, and 60 d.

DESIGN

This was a prospective randomized intervention study.

SETTING

The study was performed in a nursing home residence.

PARTICIPANTS

A total of 32 elderly female patients (age range 66-97 yr), with vitamin D deficiency was included in the study.

INTERVENTION

Participants were randomized into four groups of eight to receive a single dose of 300,000 IU ergocalciferol or cholecalciferol by oral (os) or im route.

RESULTS

25(OH)D levels sharply increased at d 3 only when vitamins were given os. The 30-d basal difference in serum 25(OH)D was significantly greater after cholecalciferol os administration (47.8 +/- 7.3 ng/ml) compared with other forms (D(3) im: 15.9 +/- 11.3; D(2) os: 17.3 +/- 4.7; D(2) im: 5 +/- 4.4; all P < 0.001). The area under the curve (AUC) of the serum 25(OH)D against time (AUC(60)) was: D(3) os, 3193 +/- 759 ng x d/ml vs. D(2) os, 1820 +/- 512, P < 0.001; and D(3) im, 1361 +/- 492 vs. D(2) im, 728 +/- 195, P < 0.01. 25(OH)D significantly influences PTH levels at 3 (P < 0.03), 7 (P < 0.01), 30 (P < 0.01), and 60 d (P < 0.05). At 60 d, the form of vitamin (cholecalciferol) significantly lowers PTH levels (P = 0.037).

CONCLUSIONS

Cholecalciferol is almost twice as potent as ergocalciferol in increasing serum 25(OH)D, when administered either by mouth or im. 25(OH)D plays a role in modulating serum PTH.

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

Osteoporosis poses a significant public health issue, causing significant morbidity and mortality. Calcium and vitamin D utilization in the optimization of bone health is often overlooked by patients and health care providers. In addition, the optimal standard of care for osteoporosis should encompass adequate calcium and vitamin D intake. Dietary intake or supplementation with calcium and vitamin D will be reviewed, including recent recommendations for increased vitamin D intake. Compliance to calcium and vitamin D therapy is paramount for effective prevention of osteoporotic fractures. A recently released algorithm (FRAX) estimating absolute fracture risk allows the health care provider to decide when pharmacologic therapy is warranted in addition to calcium and vitamin D. When pharmacologic therapy is advised, continued use of calcium and vitamin D is recommended for optimal fracture risk reduction. A 'bricks and mortar' analogy is often helpful when counseling patients and this analogy will be explained. This manuscript reviews relevant data related to calcium and vitamin D use for patients at risk for fracture due to bone loss.

Serum 25-hydroxyvitamin D and functional outcomes in the elderly

The objective of this article was to consider key evidence that treatment of vitamin D insufficiency has measurable clinical benefits for the musculoskeletal system in the elderly. The functional outcomes considered were increased bone mass, decreased rates of bone loss, improved muscle performance, reduced risk of falls, and reduced fracture incidence. Available evidence suggests that the elderly need a mean serum concentration of >/=65 nmol/L of vitamin D to improve muscle performance and reduce the risk of falling and >/=75 nmol/L to reduce the risk of fracture. Many elderly persons in the United States and elsewhere have serum 25-hydroxyvitamin D concentrations below these levels. For this reason, supplementation is likely to provide significant benefit to this segment of the population.

Effect of calcium supplementation on hip fractures

There have been numerous studies of the effects of calcium supplementation, with or without vitamin D, on fractures. Individually, they have not provided clarity regarding calcium's anti-fracture efficacy, though they have established that calcium does have beneficial effects on bone density throughout the skeleton in women. Meta-analysis of these data suggests that total fracture numbers are diminished. However, the data from the 5,500 women involved in trials of calcium monotherapy show consistent adverse trends in numbers of hip fractures (relative risk 1.50, 95% CI 1.06-2.12). Observational data from the Study of Osteoporotic Fractures show a similar increase in risk of hip fracture associated with calcium use. We hypothesize that reduced periosteal expansion in women using calcium supplementation might account for the differences in anti-fracture efficacy of calcium at the hip, in comparison with other sites. Until there are further trial results to clarify this area, the present findings suggest that reliance on high calcium intakes to reduce the risk of hip fracture in older women is not appropriate. In addition, those at risk should be looking to other agents with a proven capacity to prevent hip fractures, such as bisphosphonates.

How effective is nutritional supplementation for the prevention of stress fractures in female military recruits?

Intensive physical training can cause stress fractures in both osteoporotic patients and healthy, young adults. Female military recruits are especially vulnerable to such fractures, with a reported frequency of 5-15% during prolonged periods of intense physical activity. In this Practice Point commentary, I discuss a randomized, controlled study of nutritional supplementation for prevention of stress fractures in female US navy recruits. Lappe et al. reported that intervention with a high dose of calcium (2g daily) plus a normal dose of vitamin D(3) (800IU daily) reduced the incidence of stress fractures by 20% (P<0.003) during the 8-week study period. The authors also confirmed additional risk factors for stress fractures, such as smoking, low physical fitness and amenorrhea. Predisposing risk factors and nutritional intervention strategies that influence stress fracture occurrence in young adults at the time of their peak bone mass, therefore, seem very similar to those known to affect osteoporotic fractures in the elderly.

The skeleton as an intracrine organ for vitamin D metabolism

The endocrine hormone, 1alpha,25-dihydroxyvitamin D(3) (1,25D) is an important regulator of calcium and phosphorus homeostasis. In this context, 1,25D is generally recognized as necessary for the maintenance of a healthy skeleton through its actions on the small intestine. In this review, we highlight the direct effects of 1,25D on the constituent cells of the bone, actions that are independent of effects on the intestine and kidney. We also consider the evidence that 25D levels, not 1,25D levels, correlate best with parameters of bone health, and that the bone itself is a site of metabolic conversion of 25D into 1,25D, by virtue of its expression of the 25-hydroxyvitamin D 1alpha-hydroxylase, CYP27B1. We review the evidence that at least osteoblasts and chondrocytes, and possibly also bone resorbing osteoclasts, are capable of such metabolic conversion, and therefore that these cells likely participate in autocrine and paracrine loops of vitamin D metabolism. We conclude that the skeleton is an intracrine organ for vitamin D metabolism, challenging the long-held notion that 1,25D is solely an endocrine hormone.

Decreased bone mineral density in adult familial Mediterranean fever patients: a pilot study

We investigated the association between familial Mediterranean fever (FMF) and osteoporosis (OP) in adult patients. Thirty-five attack-free FMF patients (28 females, 7 males; mean age 36.9 +/- 5.7 years) were individually matched to control subjects on the basis of age (within 2 years) and sex. All patients were taking regular colchicine. Subjects having any condition that can cause decreased bone mineral density (BMD) were excluded from the study. BMD was measured at the spine and femur by dual X-ray absorptiometry (DXA). Data was given as the median (IQR). T scores of the spine were -0.700 (-1.097 to -0.262) and -0.450 (-0.830 to 0.112) in FMF patients and healthy controls, respectively (p > 0.05). T scores of the femur neck were -0.900 (-1.480 to -0.570) and -0.430 (-1.472 to 0.247) in FMF patients and healthy controls, respectively (p > 0.05). Total femur T scores were significantly lower in FMF patients than healthy controls (-0.780 [-1.222 to -0.085] vs. -0.100 [-0.765 to 0.537], respectively, p = 0.021). Total femur T scores were significantly decreased in adult patients with FMF. Ongoing subclinical inflammation may be associated with decreased bone mineral content in those patients.

New insights into the role of vitamin D and calcium in osteoporosis management: an expert roundtable discussion

BACKGROUND

Adequate vitamin D and calcium nutrition play a critical role in the maintenance of musculoskeletal health and are considered the first step in osteoporosis treatment.

ROUNDTABLE DISCUSSION

In February 2008 Merck Sharp & Dohme sponsored a 2-day, evidence-based expert panel on the benefits of vitamin D for the patient with osteoporosis and the role of vitamin D in combination with antiresorptive therapy for the management of osteoporosis. One of the primary objectives of the meeting was to review new data on the optimal serum 25-hydroxy vitamin D [25(OH)D] levels. The symposium was attended by 29 researchers and clinicians from Europe and the Middle East. The discussion focused on optimizing vitamin D and calcium nutrition and reducing falls and fractures in osteoporotic patients.

CONCLUSIONS

Current evidence and expert opinion suggests that optimal serum 25(OH)D concentrations should be at least 50 nmol/L (20 ng/mL) in all individuals. This implies a population mean close to 75 nmol/L (30 ng/mL). In order to achieve this level, vitamin D intake of at least 20 microg daily is required. There is a wider therapeutic window for vitamin D than previously believed, and doses of 800 IU per day, regardless of sun exposure, season or additional multivitamin use, appear to present little risk of toxicity. Apart from fracture and fall prevention, optimization of vitamin D status may also have additional general health benefits. Based on newly emerging data regarding calcium supplementation, and recommendations for increased vitamin D intake, the current recommendations for calcium intake in postmenopausal women may be unnecessarily high. In addition to vitamin D and calcium, treatment of patients with osteoporosis at high risk of fractures should also include pharmacologic agents with proven vertebral and non-vertebral fracture efficacy.

Calcium intake in elderly patients with hip fractures

BACKGROUND

Dietary calcium intake is assumed important in the prevention and treatment of osteoporosis. However, people in countries with a high calcium intake from commodities such as milk and milk products have a high incidence of hip fracture. The effect and influence of calcium intake in the prevention of osteoporotic fracture vary from different studies.

OBJECTIVE

To investigate premorbid daily calcium intake in patients with low energy hip fractures during four consecutive years.

DESIGN

In total 120 patients (mean age 78+/-8.5 (SD) years) were included between 2002 and 2005. The patients answered a structured food frequency questionnaire (FFQ) and interviews on patients' daily calcium intake from food and supplements took place during a 6-month period before the fracture. Dual energy X-ray absorptiometry (DEXA) was performed in a subgroup of 15 patients.

RESULTS

The mean daily calcium intake from food and supplementation was 970+/-500 mg. However, 38% of patients had an intake below the recommended 800 mg/day. There was no significant relationship between calcium intake and age, gender, bone mineral density, serum calcium or albumin, type of fracture or body mass index. The mean free plasma calcium concentration was 2.3+/-0.1, i.e. within the reference limit. In 2005, 80% of the patients who underwent DEXA had manifest osteoporosis. There was a trend towards decreased calcium intake over the observation period, with a mean calcium intake below 800 mg/day in 2005.

CONCLUSIONS

Hip fracture patients had a mean calcium intake above the recommended daily intake, as assessed by a FFQ. However, more than one-third of patients had an intake below the recommended 800 mg/day. The intake appeared to decrease over the investigated years. The relationship between calcium intake and fracture susceptibility is complex.

Fracture risk associated with different types of oral corticosteroids and effect of termination of corticosteroids on the risk of fractures

We conducted a case-control study on fracture risk associated with the use of orally administered prednisolone/prednisone, budesonide, methylprednisolone, and hydrocortisone to assess if the various preparations were associated with different fracture patterns. Cases were all subjects with any fracture sustained during the year 2000 (n = 124,655). For each case, three controls (n = 373,962) matched on age and gender were randomly drawn from the background population. Adjustments were made for concurrent diseases, use of other drugs, and a number of other factors. Oral prednisolone/prednisone was associated with a dose-dependent increase in fracture risk starting from a dose of around 6.7 mg/day. Oral budesonide was not associated with an increase in overall fracture risk, but the doses in general were low (<3 mg/day). Oral hydrocortisone was not associated with overall risk of fractures. Oral methylprednisolone was only used intermittently and was not associated with an increase in overall fracture risk at the low doses used. After termination of oral prednisolone/prednisone, it took more than 1 year for fracture risk to return to the levels of the background population. Oral prednisolone is associated with a dose-dependent increase in overall fracture risk. Budesonide at low doses did not seem to be associated with fracture risk. Hydrocortisone was not associated with an increase in the risk of fractures. It may take a year from last use of prednisolone/prednisone before fracture risk returns to that of the general population.

European guidance for the diagnosis and management of osteoporosis in postmenopausal women

Guidance is provided in a European setting on the assessment and treatment of postmenopausal women with or at risk from osteoporosis.

INTRODUCTION

The European Foundation for Osteoporosis and Bone disease (subsequently the International Osteoporosis Foundation) published guidelines for the diagnosis and management of osteoporosis in 1997. This manuscript updates these in a European setting.

METHODS

The following areas are reviewed: the role of bone mineral density measurement for the diagnosis of osteoporosis and assessment of fracture risk; general and pharmacological management of osteoporosis; monitoring of treatment; assessment of fracture risk; case finding strategies; investigation of patients; health economics of treatment.

RESULTS AND CONCLUSIONS

A platform is provided on which specific guidelines can be developed for national use.

Effects of calcium and vitamin D supplementation on hip bone mineral density and calcium-related analytes in elderly ambulatory Australian women: a five-year randomized controlled trial

CONTEXT

Effects of long-term calcium, with or without vitamin D, on hip bone mineral density (BMD) and bone turnover in sunny climates have not been reported.

OBJECTIVE

The aim was to evaluate the effect of vitamin D added to calcium supplementation on hip dual-energy x-ray absorptiometry BMD and calcium-related analytes.

DESIGN, SETTING, AND PARTICIPANTS

The study was a 5-yr randomized, controlled, double-blind trial of 120 community-dwelling women aged 70-80 yr.

INTERVENTIONS

The interventions were 1200 mg/d calcium with placebo vitamin D (Ca group) or with 1000 IU/d vitamin D2 (CaD group), or double placebo (control).

MAIN OUTCOME MEASURES

Hip BMD, plasma 25-hydroxyvitamin D, biomarkers of bone turnover, PTH, and intestinal calcium absorption were measured.

RESULTS

Hip BMD was preserved in CaD (-0.17%) and Ca (0.19%) groups but not controls (-1.27%) at yr 1 and maintained in the CaD group only at yr 3 and 5. The beneficial effects were mainly in those with baseline 25-hydroxyvitamin D levels below the median (68 nmol/liter). At yr 1, compared with controls, the Ca and CaD groups had 6.8 and 11.3% lower plasma alkaline phosphatase, respectively (P<or=0.02), and 28.7 and 34.5% lower urinary deoxypyridinoline to creatinine ratio, respectively (P<or=0.05). At 5 yr, this suppression was maintained only in the CaD group. CaD reduced PTH at 3 and 5 yr cf. controls (27.8 and 31.3%, P<or=0.005) in those with baseline PTH levels above the median (3.6 pmol/liter). Therapy did not affect intestinal calcium absorption at high carrier loads.

CONCLUSIONS

Addition of vitamin D to calcium has long-term beneficial effects on bone density in elderly women living in a sunny climate, probably mediated by a long-term reduction in bone turnover rate.

Responses of parathyroid hormone to vitamin D supplementation: a systematic review of clinical trials

The beneficial bone effects of vitamin D supplementation have been attributed to suppression of secondary hyperparathyroidism by 25-hydroxyvitamin D (25-OHD) levels at least 50nmol/l. In this systematic review, we have analyzed the results of 52 clinical trials, including 72 intervention groups and 6290 patients, on vitamin D supplementation in order to evaluate the experimental evidence and the effects of age and chronic immobility on responses of parathyroid hormone (PTH). The papers for this systematic review were selected through a search in PubMed and through a review of the reference lists of articles. Negative logarithmic (R(2)=0.318, p<0.001) and linear (R(2)=0.294, p<0.001) correlations were found between 25-OHD and PTH levels, when all pre- and post-trial values were scattered. Negative linear (R(2)=0.385, p<0.001) and logarithmic (R(2)=0.406, p<0.001) correlations were also found between the changes in 25-OHD and PTH levels. Age correlated negatively with changes in PTH (r=-0.476, p<0.001). The vitamin D supplementation of the chronically immobile patients resulted in a smaller decrease in PTH levels (-8.4 vs. -17.4%, p<0.001) despite a larger increase in 25-OHD levels (187.2% vs. 109.8%, p<0.001). According to the multiple regression analysis the changes in PTH were independently predicted by pre-trial PTH, changes in 25-OHD, age and chronic immobility, explaining 53.2% (R(2)=0.532) of the variation. This meta-analysis shows that responses of PTH to vitamin D supplementation are not only determined by the baseline PTH levels and changes in vitamin D status, but also by age and mobility of the patients. Our results also suggest that PTH decreases quite linearly during vitamin D supplementation at any given 25-OHD level. Longitudinal vitamin D supplementation studies on populations with wide range of mobility and age are needed to further elucidate their confounding effects. In determining the sufficient doses of vitamin D supplementation and adequate 25-OHD levels, these confounding effects and the inter-individual variation in responses of PTH to vitamin D supplementation should be taken into account.

Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial

OBJECTIVE

To determine the effect of calcium supplementation on myocardial infarction, stroke, and sudden death in healthy postmenopausal women.

DESIGN

Randomised, placebo controlled trial.

SETTING

Academic medical centre in an urban setting in New Zealand.

PARTICIPANTS

1471 postmenopausal women (mean age 74): 732 were randomised to calcium supplementation and 739 to placebo.

MAIN OUTCOME MEASURES

Adverse cardiovascular events over five years: death, sudden death, myocardial infarction, angina, other chest pain, stroke, transient ischaemic attack, and a composite end point of myocardial infarction, stroke, or sudden death.

RESULTS

Myocardial infarction was more commonly reported in the calcium group than in the placebo group (45 events in 31 women v 19 events in 14 women, P=0.01). The composite end point of myocardial infarction, stroke, or sudden death was also more common in the calcium group (101 events in 69 women v 54 events in 42 women, P=0.008). After adjudication myocardial infarction remained more common in the calcium group (24 events in 21 women v 10 events in 10 women, relative risk 2.12, 95% confidence interval 1.01 to 4.47). For the composite end point 61 events were verified in 51 women in the calcium group and 36 events in 35 women in the placebo group (relative risk 1.47, 0.97 to 2.23). When unreported events were added from the national database of hospital admissions in New Zealand the relative risk of myocardial infarction was 1.49 (0.86 to 2.57) and that of the composite end point was 1.21 (0.84 to 1.74). The respective rate ratios were 1.67 (95% confidence intervals 0.98 to 2.87) and 1.43 (1.01 to 2.04); event rates: placebo 16.3/1000 person years, calcium 23.3/1000 person years. For stroke (including unreported events) the relative risk was 1.37 (0.83 to 2.28) and the rate ratio was 1.45 (0.88 to 2.49).

CONCLUSION

Calcium supplementation in healthy postmenopausal women is associated with upward trends in cardiovascular event rates. This potentially detrimental effect should be balanced against the likely benefits of calcium on bone.

TRIAL REGISTRATION

Australian Clinical Trials Registry ACTRN 012605000242628.

Cardiovascular risks of calcium supplements in women

Increased risk of myocardial infarction outweighs the reduction in fractures

Osteoporosis in men: its pathophysiology and the role of teriparatide in its treatment

As the population ages, the burden of osteoporosis in men is expected to rise. Implementation of preventive measures such as falls prevention strategies, exercise and adequate calcium and vitamin D intake is recommended. However, when the diagnosis of osteoporosis is made, effective treatments need to be initiated to prevent fractures. As opposed to postmenopausal women, reduced bone formation is the predominant mechanism of age-related bone loss in men, making anabolic agents a logical treatment option for men with osteoporosis. Teriparatide is the only anabolic agent currently approved for treatment of osteoporosis in men. This paper summarizes the mechanism of action of teriparatide, as well as its tolerability and safety. Furthermore, the evidence supporting the efficacy of teriparatide treatment in men with osteoporosis is reviewed and its current role in the management of osteoporosis in men is discussed.