The impact of dietary calcium intake and vitamin D status on the effects of zoledronate

Summary

We investigated whether baseline dietary calcium intake or vitamin D status modified the effects of zoledronate. Neither variable influenced the effect of zoledronate on bone mineral density, bone turnover, or risk of acute phase reaction, suggesting that co-administration of calcium and vitamin D supplements with zoledronate may not always be necessary.

Introduction

Calcium and vitamin D supplements are often co-administered with bisphosphonates, but it is unclear whether they are necessary for therapeutic efficacy or minimizing side effects of bisphosphonates. We investigated whether baseline dietary calcium intake or vitamin D status modified the effect of zoledronate on bone mineral density (BMD) or bone turnover at 1 year, or the risk of acute phase reactions (APR).

Methods

Data were pooled from two trials of zoledronate in postmenopausal women without vitamin D deficiency in which calcium and vitamin D were not routinely administered. The cohort (zoledronate n?=?154, placebo n?=?68) was divided into subgroups by baseline dietary calcium intake (<800 vs. ≥800 mg/day) and vitamin D status [25-hydroxyvitamin D (25OHD) <50 vs. ≥50 nmol/L, and <75 nmol/L vs. ≥75 nmol/L] and treatment?×?subgroup interactions tested.

Results

There were 52, 86, and 36 % of the zoledronate group and 64, 94, and 46 % of the placebo group that had dietary calcium intake ≥800 mg/day, 25OHD ≥50 nmol/L, and 25OHD ≥75 nmol/L, respectively. There were no significant interactions between treatment and either baseline dietary calcium or baseline vitamin D status for lumbar spine BMD, total hip BMD, the bone turnover markers P1NP and β-CTx, or the risk of an APR. There was also no three-way interaction between baseline dietary calcium intake, baseline vitamin D status, and treatment for any of these variables.

Conclusions

Baseline dietary calcium intake and vitamin D status did not alter the effects of zoledronate, suggesting that co-administration of calcium and vitamin D with zoledronate may not be necessary for individuals not at risk of marked vitamin D deficiency.     

Vitamin D: do we get enough?

Summary

On September 29, 2011, acknowledged experts in the field of vitamin D, mainly European, were brought together in order to discuss the recent scientific advances in relation to vitamin D: the current requirements and associations with various health outcomes. In this article, the discussions resulting from the meeting are summarized.

Introduction

Several groups at risk for developing vitamin D insufficiency have been identified. Accordingly, reviews indicate that a significant percentage of the population worldwide have serum 25-hydroxyvitamin D levels below 50 nmol/l. In addition to the role of vitamin D in bone health, recent studies suggest that it may play a pivotal role in other systems, e.g., the cardiovascular system, pancreas, muscle, immune system and brain. Most evidence, however, is obtained from observational studies and yet inconclusive.

Methods

To exchange and broaden knowledge on the requirements for vitamin D and its effect on various health outcomes, a workshop entitled “Vitamin D Expert Meeting: Do we get enough?”, was organized.

Results

Despite low vitamin D levels worldwide, consensus on the definition of deficiency is not yet reached. In order to define cut-off points for vitamin D whilst taking into account extraskeletal health effects, randomized controlled trials in these fields are warranted. The experts do emphasize that there is evidence to suggest an important role for vitamin D in the maintenance of optimal bone health at all ages and that vitamin D supplementation, in most studies co-administered with calcium, reduces fracture risk in the senior population.

Conclusion

To reach a serum 25-hydroxyvitamin D level of 50 nmol/l older adults aged ≥65 years are therefore recommended to meet a mean daily vitamin D intake of 20 μg (800 IU), which is best achieved with a supplement.     

High Vitamin D Deficiency Rate in Metabolic Inpatients: Is Bariatric Surgery Planning Found Guilty?

Background

High rates of vitamin D insufficiency are usually found in obese patients, even before any malabsorptive bariatric surgery. It is not clear whether they lack vitamin D because of different food intake, different solar exposure, or different storage pathways or bioavailability in adipose tissue. To better understand vitamin D deficiency, we studied different categories of inpatients.

Methods

We collected clinical and biological data from 457 consecutive inpatients during a year: 217 nonobese diabetic patients, 159 obese nonsurgical diabetic patients, 46 obese surgical nondiabetic patients, and 35 obese surgical diabetic patients. Statistically significant differences between two mean 25-hydroxyvitamin D (25(OH)D) levels were defined at the 5 % level using a Z-test.

Results

Vitamin D deficiency was found in 69 % of the patients, while 24 % had a normal level and 7 % an optimal level. A significant difference was found between obese (25(OH)D?=?40.3 nmol/l) and nonobese patients (25(OH)D?=?46.8 nmol/l). Patients undergoing bariatric surgery were not different from the other obese patients.

Conclusion

No significant difference in 25(OH) vitamin D level could be demonstrated between obese patients before bariatric surgery and obese patients with no obesity surgery project. No difference was found between our Parisian obese population and a Spanish obese population, which benefits from a better solar exposure. Both findings suggest that obesity itself is the link with vitamin D deficiency, independently from behavioral differences.     

Non-linear relationship between serum 25-hydroxyvitamin D concentration and subsequent hip fracture

Summary

Serum 25-OH vitamin D levels were compared in 254 hip fracture subjects and 2,402 matched control subjects. There was a significant inverse association between 25-OH vitamin D and hip fracture only between 0 and 70 nmol/L.

Introduction

Vitamin D is integral to bone metabolism, however the utility of serum 25-OH vitamin D as a risk marker for hip fractures is controversial.

Methods

We conducted a case–control study of patients admitted to the hospitals with hip fractures in Calgary, Alberta, (catchment population 1.4 million) between January 1, 2007 and August 31, 2011. We searched the laboratory information system of Calgary Laboratory Services for serum 25-OH vitamin D levels within 6 months prior to admission on patients admitted to hospital with hip fractures. Cases were identified through the Calgary Laboratory Services laboratory information system and were matched to controls for age, sex, and month of testing. The hip fracture–25-OH vitamin D association was examined using multiple linear and spline regression.

Results

Of 305 subjects initially identified with hip fractures, serum 25-OH vitamin D levels were available for 254 (83 %). These were matched to 2,402 control subjects. We observed a significant (p?<?0.01) non-linear relationship such that 25-OH vitamin D was inversely associated with hip fracture only below 70 nmol/L (odds ratio?=?0.81 per 10 nmol/L increase; 95 % CI 0.86–0.93).

Conclusions

The utility of 25-OH vitamin D level as a risk marker for hip fracture depends on the cut-off level used and was of potential use only for lower levels of 25-OH vitamin D.     

Vitamin D deficiency in UK South Asian Women of childbearing age: a comparative longitudinal investigation with UK Caucasian women

Summary

This is the first 1-year longitudinal study which assesses vitamin D deficiency in young UK-dwelling South Asian women. The findings are that vitamin D deficiency is extremely common in this group of women and that it persists all year around, representing a significant public health concern.

Introduction

There is a lack of longitudinal data assessing seasonal variation in vitamin D status in young South Asian women living in northern latitudes. Studies of postmenopausal South Asian women suggest a lack of seasonal change in 25-hydroxy vitamin D [25(OH)D], although it is unclear whether this is prevalent among premenopausal South Asians. We aimed to evaluate, longitudinally, seasonal changes in 25(OH)D and prevalence of vitamin D deficiency in young UK-dwelling South Asian women as compared with Caucasians. We also aimed to establish the relative contributions of dietary vitamin D and sun exposure in explaining serum 25(OH)D.

Methods

This is a 1-year prospective cohort study assessing South Asian (n?=?35) and Caucasian (n?=?105) premenopausal women living in Surrey, UK (51° N), aged 20–55 years. The main outcome measured was serum 25(OH)D concentration. Secondary outcomes were serum parathyroid hormone, self-reported dietary vitamin D intake and UVB exposure by personal dosimetry.

Results

Serum 25(OH)D?<25 nmol/L was highly prevalent in South Asians in the winter (81 %) and autumn (79.2 %). Deficient status (below 50 nmol/L) was common in Caucasian women. Multi-level modelling suggested that, in comparison to sun exposure (1.59, 95 %CI?=?0.83–2.35), dietary intake of vitamin D had no impact on 25(OH)D levels (?0.08, 95 %CI?=??1.39 to 1.23).

Conclusions

Year-round vitamin D deficiency was extremely common in South Asian women. These findings pose great health threats regarding the adverse effects of vitamin D deficiency in pregnancy and warrant urgent vitamin D public health policy and action.     

Vitamin D status in relation to obesity, bone mineral density, bone turnover markers and vitamin D receptor genotypes in healthy Saudi pre- and postmenopausal women

Summary

The various factors that may contribute to vitamin D deficiency or insufficiency were examined among healthy Saudi pre- and postmenopausal women. Vitamin D deficiency was highly prevalent among studied Saudi women with obesity, poor sunlight exposure, poor dietary vitamin D supplementation and age as the main risk factors.

Introduction

The various factors that may contribute to vitamin D deficiency or insufficiency in relation to bone health among Saudi women are not known. The main objectives of the present study were to determine the factors influencing vitamin D status in relation to serum 25-hydroxyvitamin D (25(OH)D), intact parathyroid hormone (PTH), bone turnover markers (BTMs), bone mineral density (BMD), and vitamin D receptor genotype (VDR) in healthy Saudi pre- and postmenopausal women.

Methods

A total number of 1,172 healthy Saudi women living in the Jeddah area were randomly selected and studied. Anthropometric parameters, socioeconomic status, sun exposure index together with serum levels of 25(OH)D, calcitriol, intact PTH, Ca, PO4, Mg, creatinine, albumin, and biochemical BTMs were measured. BMD was measured by a dual energy X-ray absorptiometry and VDR genotypes were also determined.

Results

About 80.0% of Saudi women studied exhibited vitamin D deficiency (serum 25(OH)D?<?50.0?nmol/L) with only 11.8% of all women were considered with adequate vitamin D status (serum 25(OH)D?>?75?nmol/L). Secondary hyperparathyroidism was evident in 18.5% and 24.6% in pre- and postmenopausal women with 25(OH)D?<?50?nmol/L. Serum 25(OH)D was lower (P?<?0.001) and intact PTH higher (P?<?0.001) in the upper quintiles of body mass index (BMI) and waist-to-hip ratio (WHR). Multiple linear regression analysis showed that BMI, sun exposure index, poor dietary vitamin D supplementation, WHR, and age were independent positive predictors of serum 25(OH)D values.

Conclusions

Vitamin D deficiency is highly prevalent among healthy Saudi pre-and postmenopausal women and largely attributed to obesity, poor exposure to sunlight, poor dietary vitamin D supplementation, and age.     

The relationship between obesity and the increase in serum 25(OH)D levels in response to vitamin D supplementation

Summary

This study examines the relationship between obesity and the increase in serum 25(OH)D levels in response to vitamin D supplementation among adults with baseline serum 25(OH)D levels <50 nmol/L. This study revealed that the increase in serum 25(OH)D in response to vitamin D supplementation was higher in lean subjects as compared to obese subjects.

Introduction

Serum 25(OH)D is lower among obese than non-obese. This study examines the relationship between obesity and the increase in serum 25(OH)D in response to vitamin D supplementation in a large sample of adults with baseline serum 25(OH)D <50 nmol/L, relatively long average treatment duration and large average daily cholecalciferol.

Methods

The computerized database of the Clalit Health Services, which the largest nonprofit health maintenance organization in Israel, was retrospectively searched for all subjects aged ≥20 years who performed serum 25(OH)D test in 2011. Subjects with more than one test at different occasions in 2011 were identified and were included if the result of the first test was <50 nmol/L, and were treated with cholecalciferol between the first and the last test in 2011 (n?=?16,540 subjects).

Results

The mean increase in serum 25(OH)D level after treatment was 28.7 (95 % confidence interval (CI), 28.0–29.4)?nmol/L, 23.6 (23.0–24.2)?nmol/L, and 20.1 (19.6–20.6)?nmol/L in subject with BMI of <25, 25–29.9, and ≥30 kg/m², respectively (P?<?0.001). The results were similar after adjustment for the potential confounders. Similarly, the proportion of subjects who achieved serum 25(OH)D?≥?50 nmol/L after treatment was inversely associated with BMI; 65.1, 58.3, and 49.1 % for BMI of <25, 25–29.9, and?≥?30 kg/m², respectively. Compared to BMI of ≥30 kg/m², the adjusted odds ratio for achieving levels of ≥50 nmol/L were 2.12 (95 % CI, 1.94–2.31) and 1.42 (1.31–1.54) for BMI of <25 kg/m², and BMI of 25–29.9 kg/m², respectively.

Conclusions

BMI is inversely associated with the increase in serum 25(OH)D levels in response to vitamin D supplementation.     

Prevalence and seasonal variation of hypovitaminosis D and its relationship to bone metabolism in healthy Hungarian men over 50 years of age: the HunMen Study

Summary

This study reports a high prevalence of hypovitaminosis D and low bone mineral density (BMD) in a healthy Hungarian male cohort over 50 years of age. Men with 25-hydroxyvitamin D levels of <75 nmol/L had a significantly higher 10-year hip and major osteoporotic fracture probability using the country-specific fracture risk assessment (FRAX) algorithm.

Introduction

The aim of this study is to characterize the prevalence and seasonal variation of hypovitaminosis D and its relationship to bone metabolism in healthy Hungarian men over 50 years of age.

Methods

We determined levels of 25-hydroxyvitamin D (25-OH-D), PTH, osteocalcin (OC), C-terminal telopeptides of type-I collagen (CTX-I), procollagen type 1 amino-terminal propeptide (PINP), BMD at L1–L4 (LS) and femur neck (FN), daily dietary calcium intake, and the 10-year probability of hip fracture and a major osteoporotic fracture using the country-specific FRAX algorithm in 206 randomly selected ambulatory men.

Results

The mean (range) age of the volunteers was 60 (51–81) years. The prevalence of hypovitaminosis D (25-OH-D, <75 nmol/L) was 52.9%. The prevalence of low (T-score?<??1.0) BMD at the FN and LS was 45% and 35.4%, respectively. The mean (range) FRAX hip fracture and FRAX major osteoporotic fracture was 0.8% (0–9.4%) and 3.8% (1.7–16%), respectively. On comparing the vitamin D sufficient to the insufficient group, there was a statistically significant difference between the FRAX hip fracture and FRAX major osteoporotic fracture indexes. There was significant seasonal variation in the vitamin D levels; the lowest levels were measured in winter and the highest in summer.

Conclusions

A high prevalence of hypovitaminosis D and low BMD were observed in the studied Hungarian male population. This is the first study reporting higher 10-year hip and major osteoporotic fracture probability using the country-specific FRAX algorithm in individuals with hypovitaminosis D.     

Ethnic differences in 25-hydroxyvitamin D levels and response to treatment in CKD

Aim

Nutritional vitamin D [25(OH)D] deficiency is common in patients with chronic kidney disease (CKD). No studies have specifically examined the differences between ethnic groups in response to ergocalciferol (“D2”) therapy.

Methods

A retrospective analysis was performed to evaluate the effectiveness of D2 therapy as recommended by the KDOQI guidelines in 184 Hispanic and Caucasian nondialysis CKD patients.

Results

Low 25(OH)D levels (<75 nmol/L) were found in 89.4 % of Hispanics versus 61.4 % of Caucasians, despite similar degrees of CKD. Treatment per KDOQI guidelines resulted in 85.5 % of treated Hispanics and 66.7 % of treated Caucasians remaining vitamin D-deficient. Although both Hispanics and Caucasians had significant (P < 0.0001) changes in 25(OH)D levels, absolute changes were modest (12.5 ± 2.0 nmol/mL in Hispanics, 20.0 ± 3.5 nmol/L in Caucasians). The increase seen in Caucasians was significantly greater than in Hispanics (P < 0.0001). In multiple logistic regression modeling, Hispanic ethnicity remained independently associated with poorer response to therapy (P = 0.0055), even after adjustment for other factors.

Conclusions

While both Hispanics and Caucasians demonstrated suboptimal response to the KDOQI-guided vitamin D repletion strategy, Hispanic ethnicity was significantly associated with poorer response. Our findings may have implications for other darker-skinned populations, even in solar-rich environments.     

Vitamin D status of schoolchildren in Northern Algeria,seasonal variations and determinants of vitamin D deficiency

Summary

There are no published data on the vitamin D status of children living in North Africa. In 435 healthy Algerian children 5–15 years old, we found that vitamin D insufficiency (serum 25-hydroxyvitamin D (25OHD) <50 nmol/L) was frequent, especially in winter. Low vitamin D status was associated with increased parathyroid hormone (PTH) and leg deformation

Introduction

As there are no published data on the vitamin D status of children living in North Africa, we evaluated the 25OHD concentration of healthy Algerian children at the end of summer and at the end of winter. As secondary objectives, we studied the various determinants of vitamin D status and the PTH-25OHD relationship in these subjects.

Methods

Four hundred thirty-five children 5–15 years old were examined and had a blood sample in September 2010. Of them, 408 were sampled again in March 2011.

Results

Median 25OHD concentration in the whole group was 71.4 nmol/L in September and 52.9 nmol/L in March. In September, 58.4, 29.9, and 8.1 % had a 25OHD concentration below 75, 50, and 30 nmol/L respectively. In March, these percentages increased to 65.2, 41.4, and 17.4 % for the 75, 50, and 30 nmol/L threshold, respectively. In multivariate analysis, older age, darker skin phototype, low daily vitamin D and calcium intake, poor socioeconomic status, and short daily sun exposure remained significantly associated with a 25OHD <50 nmol/L at both visits. In 72 (16.6 %) children, genu varum/valgum was present. Compared to the 363 children without leg deformation, they presented more frequently with the risk factors of vitamin D insufficiency. They also had lower 25OHD concentrations and higher PTH and tALP. Serum PTH and 25OHD concentrations were negatively and significantly correlated (r?=??0.43; p?<?0.001) without a 25OHD threshold above which PTH does not decrease anymore.

Conclusion

Despite a sunny environment, vitamin D insufficiency is frequent in healthy Algerian children.     

Vitamin D Supplementation Efficacy: Sleeve Gastrectomy Versus Gastric Bypass Surgery

Background

Vitamin D deficiency is common with bariatric surgery, and few prospective studies comparing different surgical procedures have evaluated appropriate vitamin D supplementation levels. Therefore, vitamin D₃ and calcium supplementation were evaluated following gastric bypass and sleeve gastrectomy.

Methods

Women consumed 2,000 international units (IU) of vitamin D₃ and 1,500 mg calcium citrate daily for 3 months following gastric bypass (n?=?11) and sleeve gastrectomy (n?=?12). Height, weight, body mass index (BMI), serum 25-hydroxyvitamin D [25(OH)D], and serum PTH concentrations were measured preoperatively and at 3 months. Wilcoxon signed rank analyses compared body weight parameters, serum 25(OH)D and PTH concentrations, and dietary intakes of vitamin D and calcium preoperatively and at 3 months. Vitamin D deficiency was defined as a serum 25(OH)D concentration <20 ng/mL (50 nmol/L).

Results

Vitamin D deficiency decreased from 60.6 % preoperatively to 26.1 % after 3 months (P?P?Conclusions Reduced food intake increased the risk of vitamin D deficiency following bariatric surgery. However, daily supplementation with 2,000 IU of vitamin D₃ and 1,500 mg calcium citrate significantly increased 25(OH)D concentrations and reduced the percent of women who were vitamin D deficient. Although serum 25(OH)D concentrations did not reach levels associated with detrimental health effects, several women remained vitamin D deficient and more aggressive supplementation may be indicated.     

No change in calcium absorption in adult Pakistani population before and after vitamin D administration using strontium as surrogate

Summary

Vitamin D, parathyroid hormone levels and calcium absorption was assessed before and after cholecalciferol using Strontium as a surrogate. Increase in 25OHD, lowering of iPTH with no effect on Sr absorption was seen, suggesting the possibility that maximal Ca absorption had already been achieved in these volunteers.

Introduction

This paper discusses the determination of calcium (Ca) absorption, using strontium (Sr) as a surrogate, before and after a single IM injection of vitamin D₃ (600,000 IU).

Methods

Baseline serum 25-hydroxyvitamin D (25OHD), Sr, Ca, P, and intact parathyroid hormone (iPTH) were determined in 53 fasting volunteers, followed by administrating (PO) 0.03 mM (4.8 mg/kg) SrCl₂ and collecting blood at 0.5, 1 and 4 h to determine the absorption (AUC_0→t ) of Sr. Following the initial absorption test, volunteers received a single IM injection of 600,000 IU vitamin D₃. Two months later, the fasting serum and the Sr absorption test were repeated, as described above.

Results

The IM injection of vitamin D₃ caused a significant increase in fasting 25OHD (from 43.5?±?19 to 66.1?±?19.1 nmol/L (p?<?0.001)) and a trend toward lower serum iPTH (from 59.8?±?27.8 to 53?±?31 ng/L). Fasting serum Ca and P remained unchanged. A higher 25OHD level failed (p?=?0.32) to translate into a higher rate of Sr absorption. AUC_0→4 h were almost identical before and after the IM injection of vitamin D₃.

Conclusion

A single vitamin D₃ injection of 600,000 IU significantly increase mean 25OHD concentration and tended to lower iPTH concentrations in volunteers with initially low 25OHD status, suggesting to utilize this simple form of treatment to improve vitamin D status and to have a possible biological effect on Ca homeostasis. However, we found no obvious effect on Sr absorption, suggesting the possibility that maximal vitamin D-dependent Ca absorption had already been achieved in these volunteers at a lower vitamin D status.     

Effect of oral cholecalciferol 2,000 versus 5,000 IU on serum vitamin D, PTH, bone and muscle strength in patients with vitamin D deficiency

Summary

Treatment of vitamin D deficiency for 3 months with oral cholecalciferol 5,000 IU daily was more effective than 2,000 IU daily in achieving optimal serum 25-hydroxyvitamin D (25OHD) concentrations. Optimal 25OHD serum level calculated to be 63.8 nmol/L. All parameters of muscle strength improved following administration of cholecalciferol for 3 months.

Introduction

The aim of this study was to determine the optimal dose of cholecalciferol required to achieve target serum 25OHD level ≥75 nmol/L and its relationship to both bone turnover and muscle strength.

Methods

Thirty deficient patients (serum 25OHD ≤50 nmol/L) were randomly assigned into two groups—i.e. 2,000 and 5,000 IU/day. Data were collected at baseline, at 2 and 3 months post-therapy: (a) clinical demographics, (b) dietary calcium recall, (c) physical tests of muscle function and (d) biochemistry. Statistical analysis used paired student t test and analysis of variance. Regression analysis was used to determine relationship between serum 25OHD and parathyroid hormone (PTH).

Results

Twenty-six (87%) patients completed 3 months of therapy. The percent increase in serum 25OHD (compared to baseline) was 82.7% in 2,000-IU group and 219.5% in 5,000-IU group. All participants (100%) achieved a serum 25OHD concentration >50 nmol/L; only 5 subjects (45.4%) in 2,000-IU group compared to 14 subjects (93.3%) in 5,000-IU group achieved final 25OHD concentration ≥75 nmol/L (p?<?0.01). In the regression analysis, the reflexion point at which the PTH level increased above the normal range was calculated to be 63.8 nmol/L 25OHD. All parameters of muscle strength showed trends in improvements following the administration of both the 2,000 and 5,000 IU doses. No patient reported untoward side effects and no patient developed hypercalcaemia.

Conclusion

Treatment for 3 months with oral cholecalciferol 5,000 IU daily may be more effective than 2,000 IU daily in achieving optimal serum 25OHD concentrations in vitamin D-deficient patients.     

Vitamin D status and parathyroid hormone relationship in adolescents and its association with bone health parameters: analysis of the Northern Ireland Young Heart’s Project

Summary

In girls, a plateau in parathyroid hormone (PTH) was observed at a 25-hydroxyvitamin D (25(OH)D) concentration of approximately 60 nmol/l. In boys, there was no plateau in PTH concentrations as 25(OH)D concentration increased. A 25(OH)D threshold of 60 nmol/l appears to have implications for bone health outcomes in both girls and boys.

Introduction

Our objective was to investigate if there is a threshold 25(OH)D concentration where a plateau in PTH concentration is evident and to examine the impact of this relationship on bone mineral density (BMD) and bone turnover in a representative sample of adolescents.

Methods

We conducted a cross-sectional analysis among 1,015 Northern Irish adolescents aged 12 and 15 years. Serum 25(OH)D, PTH, osteocalcin, type 1 collagen cross-linked C-telopeptide (CTx), and BMD of the nondominant forearm and heel were measured. Nonlinear regression analysis was used to model the association between 25(OH)D and PTH.

Results

In girls, a plateau in PTH was observed at a 25(OH)D concentration of approximately 60 nmol/l (PTH?=?47.146?+?370.314?×?exp^{(?0.092?×?25(OH)D)}) while no plateau in PTH was observed in boys (PTH?=?42.144?+?56.366?×?exp^{(?0.022?×?25(OH)D)}). Subjects with 25(OH)D levels <60 nmol/l had significantly higher osteocalcin concentrations (P?<?0.05) compared with those who had ≥60 nmol/l, while no significant (P?>?0.05) differences were noted for CTx concentrations. In girls only, nondominant forearm BMD but not heel BMD was significantly higher (P?=?0.046) in those with 25(OH)D concentrations?≥?60 nmol/l.

Conclusions

Serum 25(OH)D levels above 60 nmol/l in Northern Irish adolescent girls prevent an increase in serum PTH levels and maintaining 25(OH)D >60 nmol/l in both girls and boys may lead to improved bone health outcomes.     

Longitudinal changes and seasonal variations in serum 25-hydroxyvitamin D levels in different age groups: results of the Longitudinal Aging Study Amsterdam

Summary

Vitamin D levels remained fairly stable during ageing with increasing levels in persons aged 55–65 years old and decreasing levels in persons aged 65–88 years old. The seasonal variation was larger than the longitudinal change. Our findings implicate that vitamin D supplementation becomes more important in older age groups and during wintertime.

Introduction

Longitudinal changes in serum 25-hydroxyvitamin D (25-OHD) levels during aging have not been studied extensively. Two studies showed increasing serum 25-OHD levels. One of these studies suggested that there might be decreasing levels in persons aged 65 years and older. The objectives of the current study are the following: (1) to examine longitudinal changes in serum 25-OHD levels in different age groups and (2) to describe the seasonal variation in different age groups.

Methods

Data of the Longitudinal Aging Study Amsterdam (LASA), an ongoing cohort study, were used. Two different cohorts were included: (1) younger cohort: aged 55–65 years old at baseline, n?=?738, follow-up of 6 years and (2) older cohort: aged 65–88 years old at baseline, n?=?1,320, follow-up of 13 years.

Results

At baseline, average levels were 56.5 nmol/L in the younger cohort and 51.1 nmol/L in the older cohort. In the younger cohort, a longitudinal increase in the mean serum 25-OHD levels of 4 nmol/L in 6 years was observed; in the older cohort, a longitudinal decrease in the mean serum 25-OHD levels of 4 nmol/L in 13 years was observed. The seasonal variation was ±12 nmol/L in the younger cohort and ±7 nmol/L in the older cohort.

Conclusions

Long-term serum 25-OHD levels remained fairly stable during aging with slightly increasing levels in persons aged 55–65 years old and slightly decreasing levels in persons aged 65–88 years old. On average, the seasonal variation was larger than the longitudinal change. Our findings implicate that vitamin D supplementation becomes more important in older age groups and during wintertime.     

Effect of alendronate in elderly patients after low trauma hip fracture repair

Summary

One year of once weekly alendronate, when given shortly after the surgical repair of a hip fracture, produces reductions in bone markers and increases proximal femoral bone density. The therapy was well tolerated.

Introduction

Hip fracture is the most devastating type of osteoporotic fracture and increases notably the risk of subsequent fractures. The aim of this paper was to evaluate the effects of 1 year therapy with a weekly dose of alendronate in the bone mineral density and bone markers in elderly patients after low trauma hip fracture repair.

Methods

Two hundred thirty-nine patients (81?±?7 years; 79.8% women) were randomized to be treated either with calcium (500 mg/daily) and vitamin D₃ (400 IU/daily; Ca–Vit D group) or with alendronate (ALN, 70 mg/week) plus calcium and vitamin D₃ (500 mg/daily and 400 IU/daily, respectively; ALN + Ca–Vit D group).

Results

One hundred forty-seven (61.5%) patients completed the trial. Alendronate increased proximal femoral bone mineral density (BMD) in the intention-to-treat analysis (mean difference (95% confidence interval); total hip 2.57% (0.67; 4.47); trochanteric 2.96% (0.71; 5.20), intertrochanteric 2.32% (0.36; 4.29)), but the differences were not significant in the BMD of the femoral neck (0.47%; (?2.03; 2.96) and the lumbar spine (0.69%; (?0.86; 2.23)). Bone turnover markers decreased during alendronate treatment.

Conclusion

The present study demonstrates for the first time the anti-resorptive efficacy of alendronate given immediately after surgical repair in an elderly population with recent hip fracture. This effect should positively affect the rate of subsequent fractures.     

Profile of changes in bone turnover markers during once-weekly teriparatide administration for 24 weeks in postmenopausal women with osteoporosis

Summary

Changes in bone turnover markers with weekly 56.5 μg teriparatide injections for 24 weeks were investigated in women with osteoporosis. Changes in bone turnover markers 24 h after each injection of teriparatide were constant. During the 24 week period, bone formation markers increased and baseline bone resorption marker levels were maintained.

Introduction

This study aimed to clarify the changes in bone turnover markers during 24 weeks of once-weekly teriparatide injections in postmenopausal women with osteoporosis.

Methods

The 24 h changes in pharmacokinetics (PK), calcium metabolism, and bone turnover markers (serum osteocalcin, procollagen type I N-terminal propeptide (P1NP), urinary cross-linked N-telopeptide of type I collagen (NTX), deoxypiridinoline (DPD)) after each injection of 56.5 μg teriparatide at the data collection weeks (0, 4, 12, and 24 weeks) were investigated. The changes were evaluated by comparison with the data at 0 h in each data collection week.

Results

Similar 24 h changes in each parameter after injection of teriparatide were observed in each data collection week. Serum calcium increased transiently, and intact PTH decreased 4–8 h after injection; serum calcium subsequently returned to baseline levels. Calcium and intact PTH levels decreased for 24 weeks. Although serum osteocalcin decreased at 24 h, it was significantly increased at 4 weeks. P1NP decreased transiently and then increased significantly at 24 h. P1NP was significantly increased at 4 weeks. Urinary NTX and DPD were significantly increased transiently and then decreased at 24 h. The urinary DPD level decreased significantly at 4 weeks.

Conclusions

Twenty-four hour changes in PK, calcium metabolism, and bone turnover markers showed the same direction and level after once-weekly teriparatide injections for 24 weeks, with no attenuation of the effect over time. After 24 weeks, the bone formation marker, serum osteocalcin, increased significantly, but the serum P1NP, did not. Bone resorption markers decreased or remained the same.     

Vitamin D2 from light-exposed edible mushrooms is safe, bioavailable and effectively supports bone growth in rats

Summary

Widespread poor vitamin D status, a health risk for bone disease, increases the need for new food sources of vitamin D. Light-exposed edible mushrooms synthesize vitamin D₂. Bioavailability, safety, and efficacy of high levels of vitamin D₂ from mushrooms to support bone health was established in chronically fed growing rats.

Introduction

Poor vitamin D status from reduced sun exposure is made worse by limited access to vitamin D-containing foods. Exposing white button mushrooms to ultraviolet B (UVB) light markedly increases their vitamin D₂ content, creating a new food source of vitamin D. We used a growing rat model to determine safety, bioavailability, and efficacy in support of bone growth by vitamin D₂ from UVB-exposed mushrooms.

Methods

We fed 150 weanling female rats one of five diets for 10 weeks, all formulated on AIN-93 G. Control diets contained no mushrooms either with or without vitamin D₃. Other diets contained 2.5% and 5.0% of UVB-exposed or -unexposed mushrooms. Safety of the high levels of vitamin D₂ from mushrooms was assessed by animal growth and by Von Kossa staining for soft tissue calcification. Bioavailability was determined from changes in circulating levels of 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH). Efficacy in support of bone growth was determined from measures of femur bending properties, size, mineralization, and microarchitecture.

Results

Diets containing 2.5% and 5.0% light-exposed mushrooms significantly raised 25(OH)D and suppressed PTH levels compared to control-fed rats or rats fed 5.0% mushroom unexposed to light. Microarchitecture and trabecular mineralization were only modestly higher in the light-treated mushroom-fed rats compared to the controls. Von Kossa staining revealed no soft tissue calcification despite very high plasma 25(OH)D.

Conclusions

Vitamin D₂ from UVB-exposed mushrooms is bioavailable, safe, and functional in supporting bone growth and mineralization in a growing rat model without evidence of toxicity.     

Prospective evaluation of renal function,serum vitamin D level,and risk of fall and fracture in community-dwelling elderly subjects

Summary

This prospective study in elderly showed that kidney function plays a minor role in explaining the high prevalence of vitamin D deficiency seen in noninstitutionalized elderly subjects. However, 25-hydroxyvitamin D levels were clearly inversely associated with risk for first fall, which was especially seen in subjects with calcium levels above median.

Introduction

Few prospective studies in elderly exist that have investigated the association of renal dysfunction and vitamin D status on risk of falls. The aim of this study is to evaluate the association of renal function with 25-hydroxyvitamin D (25-OH-D) levels and, secondly, to assess the role of both factors on the risk of falls and subsequent bone fractures.

Methods

This is a prospective population-based cohort study among noninstitutionalized elderly subjects during a 1-year follow-up. 25-OH-D levels and renal function were estimated, the latter by cystatin C-based equations. Information on falls was assessed prospectively.

Results

Overall, 1,385 subjects aged 65 and older were included in the study (mean age 75.6 years), of whom 9.2 % had a 25-OH-D serum level above 75 nmol/L (US units 30 ng/mL); 41.4 %, between 50 and 75 nmol/L (US units 20 to 29 ng/mL, insufficiency); and 49.4 %, <50 nmol/L (US units <20 ng/mL, deficiency). We found no association of chronic kidney disease with risk of first fall. In contrast, 25-OH-D serum categories were clearly associated with risk of first fall and we found evidence of effect modification with calcium levels. In the group with a calcium level above the median (≥9.6 mg/dL), subjects with 25-OH-D serum level between 50 and 75 nmol/L and with concentrations <50 nmol/L had a hazard rate ratio (HRR) of 1.75 (1.03–2.87) and 1.93 (1.10–3.37) for risk of first fall. 25-OH-D serum levels were also associated with several markers of inflammation and hemodynamic stress.

Conclusions

We demonstrated an association of 25-OH-D serum levels and risk of first fall, which was especially evident in subjects with serum calcium in upper normal, independent of renal function.