Vitamin D supplementation and bone mineral density in early postmenopausal women

BACKGROUND: Increased vitamin D intake may preserve or increase bone mineral density (BMD) in older persons. OBJECTIVE: A 2-y double-blind study was undertaken to determine whether weekly administration of 10 000 units of vitamin D(2) maintained or increased BMD in younger postmenopausal women more efficiently than did calcium supplements alone. DESIGN: One hundred eighty-seven women who were >or= 1 y postmenopausal were randomly assigned to take either 1000 mg Ca/d after the evening meal or 1000 mg Ca/d plus 10 000 U vitamin D(2)/wk in a double-blind, placebo-controlled format. The BMD of the proximal forearm, lumbar spine, femoral neck, Ward's triangle, and femoral trochanter was measured at 6-mo intervals by osteodensitometry. RESULTS: During the 2-y period, there was no significant difference in the change in BMD at any site between the subjects taking calcium supplements and those taking calcium plus vitamin D(2). Both groups significantly (P < 0.005) gained BMD in Ward's triangle and the femoral trochanter but significantly (P < 0.005) lost bone in the proximal radius. There was no significant change in the lumbar spine or femoral neck BMD. CONCLUSION: In younger postmenopausal women ( age: 56 y) whose average baseline serum 25-hydroxyvitamin D concentration was well within the normal range, the addition of 10 000 U vitamin D(2)/wk to calcium supplementation at 1000 mg/d did not confer benefits on BMD beyond those achieved with calcium supplementation alone.     

Phylloquinone (vitamin K1) intakes and serum undercarboxylated osteocalcin levels in Irish postmenopausal women

Low phylloquinone (vitamin K1) intakes have been associated with low bone mineral density in older adults. Phylloquinone intakes and serum undercarboxylated osteocalcin (ucOC) levels were assessed in ninety-seven apparently healthy, free-living Irish women aged 50-75 years. Phylloquinone intakes were estimated using a detailed dietary history, which measured habitual food intakes from a typical 14 d period, and recently published food composition data for phylloquinone. Fasting serum ucOC was measured using an enzyme immunoassay. The median daily intake of phylloquinone in the group from all sources was 108.8 microg and from food sources only was 106.6 microg, indicating that approximately 99 % of the phylloquinone came from food. Vegetables and vegetable dishes contributed 67 % of the total phylloquinone intake, but further analysis showed that broccoli, cabbage and lettuce were the primary sources, making a total contribution of 44 %. Twenty per cent of the women had a phylloquinone intake below the UK recommendation of 1 microg/kg body weight per day and 34 % failed to meet the US Adequate Intake value of 90 microg/day. Mean serum ucOC levels in the women were 6.2 (SD 1.7) ng/ml and were predicted by phylloquinone intake (beta -2.20, generated from log-transformed phylloquinone intake data; P=0.04). On the basis of comparisons with both UK recommendations and US Adequate Intakes for phylloquinone, the habitual intakes of phylloquinone in a high proportion of Irish postmenopausal women may not be adequate.     

Tanning is associated with optimal vitamin D status (serum 25-hydroxyvitamin D concentration) and higher bone mineral density

BACKGROUND: Vitamin D is made in the skin on exposure to solar radiation, and it is necessary to optimal skeletal health. Subjects who use a tanning bed that emits ultraviolet B radiation (290-315 nm) are likely to have higher 25-hydroxyvitamin D [25(OH)D] concentrations than do subjects who do not regularly use a tanning bed. OBJECTIVE: The first objective of this study was to ascertain whether subjects who regularly use a tanning bed have higher 25(OH)D concentrations than do subjects who do not use a tanning bed. The second objective was to ascertain whether higher 25(OH)D concentrations correlated positively with bone mineral density. DESIGN: This cross-sectional analysis examined 50 subjects who used a tanning bed at least once a week and 106 control subjects. Each subject gave a blood specimen for measurement of serum 25(OH)D and parathyroid hormone concentrations. Each subject underwent bone mineral density testing of the hip and spine. RESULTS: Subjects who used a tanning bed had serum 25(OH)D concentrations 90% higher than those of control subjects (115.5 +/- 8.0 and 60.3 +/- 3.0 nmol/L, respectively; P <0.001). Subjects who used a tanning bed had parathyroid hormone concentrations 18% lower than those of control subjects (21.4 +/- 1.0 and 25.3 +/- 0.8 pg/mL, respectively; P=0.01). Tanners had significantly higher BMD and z scores at the total hip than did nontanners. CONCLUSION: The regular use of a tanning bed that emits vitamin D-producing ultraviolet radiation is associated with higher 25(OH)D concentrations and thus may have a benefit for the skeleton.     

Vitamin D supplementation,body weight and human serum 25-hydroxyvitamin D response: a systematic review

Purpose

There is considerable variation in incremental circulating 25-hydroxyvitamin D (25OHD) levels on vitamin D supplements, even when similar age groups and identical vitamin D doses are compared. We therefore aimed to investigate the importance of body weight for the dose–response relation in circulating 25OHD.

Methods

We performed a systematic review of randomized placebo-controlled vitamin D supplementation trials in all age groups ≥10 years to clarify the influence of body weight and other parameters on incremental circulating 25OHD levels (difference between baseline and in-study values) in vitamin D-deficient and non-deficient individuals.

Results

We included 144 cohorts from 94 independent studies, published from 1990 to November 2012, in our systematic review. There was a logarithmic association between vitamin D dose per kg body weight per day and increment in circulating 25OHD. In multivariable regression analysis, vitamin D dose per kg body weight per day could explain 34.5 % of variation in circulating 25OHD. Additional significant predictors were type of supplement (vitamin D₂ or vitamin D₃), age, concomitant intake of calcium supplements and baseline 25OHD, explaining 9.8, 3.7, 2.4 and 1.9 %, respectively, of the variation in circulating 25OHD.

Conclusions

This systematic review demonstrates that body weight is an important predictor of variation in circulating 25OHD in cohorts on vitamin D supplements. Our model provides an estimate of the daily vitamin D dose that is necessary for achieving adequate circulating 25OHD levels in vitamin D-insufficient or vitamin D-deficient individuals/cohorts with different body weights and ages.     

Vitamin D status: effects on parathyroid hormone and 1, 25-dihydroxyvitamin D in postmenopausal women

BACKGROUND: Low serum 25-hydroxyvitamin D ?25(OH)D concentrations are commonly found in the elderly and are associated with hip fracture. Treatment with vitamin D and calcium can reduce the risk of fracture. The relation between the rise in parathyroid hormone (PTH) with age and the decrease in 25(OH)D is not clear. Neither is there any consensus on the serum concentration of 25(OH)D required for bone health. OBJECTIVE: Our objective was to study the relations between serum PTH, serum vitamin D metabolites, and other calcium-related variables in postmenopausal women. DESIGN: This was a cross-sectional study of 496 postmenopausal women without vertebral fractures attending our menopausal osteoporosis clinics. RESULTS: PTH was significantly positively related to age and serum 1, 25-dihydroxyvitamin D ?1,25(OH)(2)D and inversely related to 25(OH)D and plasma ionized calcium. There was a step-like increase in PTH as serum 25(OH)D fell below 40 nmol/L. In women with 25(OH)D concentrations >40 nmol/L, 1,25(OH)(2)D was positively related to 25(OH)D; in women with 25(OH)D concentrations 40 nmol/L, 1,25(OH)(2)D was most closely (inversely) related to plasma creatinine. Therefore, with serum 25(OH)D concentrations increasingly <40 nmol/L, serum 1,25(OH)(2)D becomes critically dependent on rising concentrations of PTH. CONCLUSION: The data suggest that aging women should maintain 25(OH)D concentrations >40 nmol/L (which is the lower limit of our normal range for healthy young subjects) for optimal bone health.     

妊娠糖尿病伴亚临床甲减对孕妇骨密度及骨钙素、25-羟基维生素D的影响

目的:探讨妊娠糖尿病伴亚临床甲减对孕妇骨密度及骨钙素、25-羟基维生素D的影响。方法:以本院内分泌科确诊的妊娠期糖尿病伴亚临床甲减孕妇120例为观察组,同期产前检查健康孕妇120例为对照组,检测两组孕妇骨密度(BMD)及骨钙素(OC)、25-羟基维生素D3(25-OH-VD3),并观察母婴妊娠结局。结果:观察组骨量正常率(72.5%)低于对照组(85.0%),骨量减少发生率(20.0%)和OC(9.86±0.13μg/L)高于对照组(5.0%、7.21±0.15μg/L),25-OH-VD(16.09±5.34μg/L)和跟骨BMD水平(0.91±0.18 g/cm2)低于对照组(18.96±6.36μg/L、1.14±0.21g/cm2)(均P<0.05);观察组新生儿低出生体质量(20.0%)和新生儿窒息发生率(10.0%)高于对照组(5.0%、1.7%)。结论:妊娠糖尿病伴亚临床甲减可降低孕妇的骨密度,影响骨钙素、25-羟基维生素D表达水平,增加新生儿窒息、低体重风险,应引起临床重视。     

Comparative effects of vitamin K and vitamin D supplementation on calcium balance in young rats fed normal or low calcium diets

We examined the effect of vitamin K and vitamin D supplementation on calcium balance in young rats fed a normal or low calcium diet. Eighty female Sprague-Dawley rats, 6 wk of age, were randomized by the stratified weight method into eight groups with 10 rats in each group: 0.5% (normal) or 0.1% (low) calcium diet, 0.5% or 0.1% calcium diet+vitamin K (vitamin K2, menatetrenone, 30 mg/100 g, food intake), 0.5% or 0.1% calcium diet+vitamin D (25 microg/100 g, food intake), and 0.5% or 0.1% calcium diet+vitamin K+vitamin D. The duration of the study was 10 wk. Vitamin K supplementation promoted the reduction in urinary calcium excretion and retarded the abnormal elevation of serum PTH level in rats fed a low calcium diet, and stimulated intestinal calcium absorption in rats fed a normal calcium diet. Vitamin D supplementation stimulated intestinal calcium absorption with prevention of the abnormal elevation of serum PTH levels and prevented hypocalcemia in rats fed a low calcium diet, and stimulated intestinal calcium absorption in rats fed a normal calcium diet. The stimulation of intestinal calcium absorption was associated with increased serum 1,25-dihydroxyvitamin D levels. An additive effect of vitamin K and vitamin D on intestinal calcium absorption was found only in rats fed a normal calcium diet. This study shows the differential effects of vitamin K and vitamin D supplementation on calcium balance in young rats fed a normal or low calcium diet.     

Vitamin D status in pregnant Indian women across trimesters and different seasons and its correlation with neonatal serum 25-hydroxyvitamin D levels

The present cross-sectional study was conducted to determine the vitamin D status of pregnant Indian women and their breast-fed infants. Subjects were recruited from the Department of Obstetrics, Armed Forces Clinic and Army Hospital (Research and Referral), Delhi. A total of 541 apparently healthy women with uncomplicated, single, intra-uterine gestation reporting in any trimester were consecutively recruited. Of these 541 women, 299 (first trimester, ninety-seven; second trimester, 125; third trimester, seventy-seven) were recruited in summer (April-October) and 242 (first trimester, fifty-nine, second trimester, ninety-three; third trimester, ninety) were recruited in winter (November-March) to study seasonal variations in vitamin D status. Clinical, dietary, biochemical and hormonal evaluations for the Ca-vitamin D-parathormone axis were performed. A subset of 342 mother-infant pairs was re-evaluated 6 weeks postpartum. Mean serum 25-hydroxyvitamin D (25(OH)D) of pregnant women was 23.2 (SD 12.2) nmol/l. Hypovitaminosis D (25(OH)D < 50 nmol/l) was observed in 96.3 % of the subjects. Serum 25(OH)D levels were significantly lower in winter in the second and third trimesters, while serum intact parathormone (iPTH) and alkaline phosphatase levels were significantly higher in winter in all three trimesters. A significant negative correlation was found between serum 25(OH)D and iPTH in mothers (r - 0.367, P = 0.0001) and infants (r - 0.56, P = 0.0001). A strong positive correlation was observed between 25(OH)D levels of mother-infant pairs (r 0.779, P = 0.0001). A high prevalence of hypovitaminosis D was observed in pregnancy, lactation and infancy with no significant inter-trimester differences in serum 25(OH)D levels.     

Effect of phylloquinone supplementation on biochemical markers of vitamin K status and bone turnover in postmenopausal women

While current intakes of phylloquinone (vitamin K1) in many populations are believed to be sufficient to maintain normal blood coagulation, these may be insufficient to cover the requirements for optimal bone metabolism. Therefore, the objective of the present study was to investigate the effect of increasing phylloquinone intakes above the usual dietary intake for 6 weeks on biochemical markers of vitamin K status and bone turnover in postmenopausal women. Thirty-one postmenopausal women completed this 3 x 6-week randomised cross-over study, in which volunteers were supplemented with 0 (placebo), 200, and 500 microg phylloquinone/d. In addition, the volunteers were given 10 microg vitamin D3/d throughout the study period. With increasing phylloquinone intake, the concentration of serum gamma-carboxylated and under-gamma-carboxylated osteocalcin was significantly increased and decreased, respectively, in a dose-dependent manner (P < 0.001). Mean serum phylloquinone concentration was significantly (P < 0.001) higher with daily supplementation with 500 microg phylloquinone/d compared with that during either of the placebo or 200 microg phylloquinone/d supplementation periods, which did not differ (P = 0.15). Serum total osteocalcin was significantly (P < 0.001) increased in response to daily supplementation with 500 (but not 200) microg phylloquinone compared with placebo. Serum bone-specific alkaline phosphatase as well as the urinary markers of bone resorption (N-telopeptide cross-links of collagen, pyridinoline and deoxypyridinoline) and urinary gamma-carboxyglutamate were unaffected by phylloquinone supplementation. In conclusion, while daily supplementation with 200 and 500 microg phylloquinone/d for 6 weeks increased vitamin K status in postmenopausal women, it had no effect on bone turnover.     

Evaluation of bone mineral density and 25-hydroxyvitamin D levels in subjects with silica exposure

Objective

The purpose of the study was to evaluate the bone mineral density (BMD) and 25-hydroxyvitamin D (25(OH)D) levels in patients with silica exposure.

Materials and methods

The study included 104 male subjects with silica exposure and 36 healthy subjects. Posterior–anterior radiographs were classified according to the International Labour Office (ILO) Classification. Category 0 patients were classified as Group I (n = 54), category I patients were classified as Group II (n = 25), Category II and III patients were classified as Group III (n = 25).

Results

Femoral neck BMD values were significantly lower in Group III (p = 0.007). Lumbar vertebrae BMD values were significantly lower in all groups with silica exposure than in the control group (p = 0.000). The osteoporosis rate was significantly higher in Group III (p = 0.000). Subjects with silica exposure were determined to have diminished 25(OH)D levels (p = 0.012).

Conclusion

The results of this study demonstrated that subjects with silica exposure have diminished BMD and 25(OH)D levels.

     

Vitamin K supplementation does not significantly impact bone mineral density and biochemical markers of bone in pre- and perimenopausal women

Because of its role in osteoblastic metabolism, vitamin K has been studied with respect to bone. However, there has been limited research examining the influence of long-term vitamin K supplementation on bone mineral density (BMD). Therefore, the purpose of this study was to assess the impact of 6 months of vitamin K supplementation on BMD and biomarkers of bone in pre- and perimenopausal women. Based on previous work, we hypothesized that vitamin K would improve BMD and biochemical markers of bone formation. A double-blind, placebo-controlled, randomized trial is an effective way to study the impact of long-term supplementation. Thus, 14 pre- and perimenopausal women, 25 to 50 years of age, were randomly assigned to an experimental group (E) that received 600 μg/d of vitamin K in the form of phylloquinone (K₁) or a control group (C) that received identical-looking placebo tablets. Regional BMD and percent body fat, measured by dual-energy x-ray absorptiometry, and serum osteocalcin and urinary N-telopeptide levels were all assessed at 0, 3, and 6 months. When BMD was measured across time, C had a significant increase (P = .011) in greater trochanter BMD compared to E. The E group had a nonsignificant increase (P = .067) in shaft BMD compared to the C group. There was no significant difference between E and C in serum osteocalcin concentrations over time. Urinary N-telopeptide levels increased significantly over time in E compared to C (P = .008). Six months of 600 μg/d vitamin K₁ supplementation did not improve regional BMD in this group of pre- and perimenopausal women.     

A prospective study of serum 25-hydroxyvitamin D levels, blood pressure, and incident hypertension in postmenopausal women

In randomized trials, the effect of vitamin D supplementation on blood pressure has been equivocal, while most prospective cohort studies have shown that the risk of incident hypertension is lower in people with higher levels of 25-hydroxyvitamin D (25(OH)D). The authors examined the association between levels of 25(OH)D and changes in blood pressure and incident hypertension in 4,863 postmenopausal women recruited into the Women's Health Initiative between 1993 and 1998. Over 7 years, there were no significant differences in the adjusted mean change in systolic or diastolic blood pressure by quartile of 25(OH)D. The covariate-adjusted risk of incident hypertension was slightly lower in the upper 3 quartiles of 25(OH)D compared with the lowest quartile, but this was statistically significant only in the third quartile (hazard ratio = 0.67, 95% confidence interval: 0.46, 0.96). There was no significant linear or nonlinear trend in the risk of incident hypertension by untransformed or log-transformed continuous values of 25(OH)D. In postmenopausal women in this study, serum levels of 25(OH)D were not related to changes in blood pressure, and evidence for an association with lower risk of incident hypertension was weak.     

Phytoestrogen and multiple vitamin/mineral effects on bone mineral density in early postmenopausal women: a pilot study

The purpose of the study was to assess the effect of a combination regimen of herbs, vitamins, and minerals on bone mineral density (BMD) in early postmenopausal women via a 2-year, single-blind, uncontrolled, prospective trial. BMD was measured by dual energy x-ray absorptiometry (DEXA) at baseline and at 6, 12, and 24 months. Results of lumbar spine, hip, and forearm densities did not differ significantly from historical controls derived from other recent trials using a similar patient population. Bone mineral losses are reported on an annualized basis over the 2 years for the 12 women who completed the trial: spine (-1.42% per year), hip (-0.43% per year), forearm (-1.42% per year). Six women were withdrawn from the trial by the investigators because of excessive losses of bone mineral, and 1 of these women was diagnosed with hyperparathyroidism. There were no metabolic diseases to explain the losses in the remaining 5 withdrawn subjects. Four of 21 subjects experienced adverse side effects, necessitating dropping out by 3 of these women. In conclusion, the combined treatment regimen of a menopause symptom-oriented herbal blend plus a high potency vitamin/mineral was unsuccessful in protecting women against the predictable acceleration of bone mineral losses associated with early postmenopause.     

Serum 25(OH)D response to vitamin D3 supplementation: A meta-regression analysis

ObjectiveThe aim of this study was to review factors that influence serum 25(OH)D when patients are given vitamin D supplements.MethodsFrom a comprehensive search of all randomized controlled clinical trials with vitamin D₃ supplementation available on PubMed up to November 2011, we selected 33 with 43 treatment arms that included at least 30 adult participants. The achieved pooled mean difference (PMD) and 95% confidence intervals (CIs) were calculated using the random-effects models. Meta-regression and subgroup analyses were performed for prespecified factors, including dose, duration, baseline serum 25(OH)D, and age.ResultsWith a mean baseline serum 25(OH)D of 50.4 nmol/L, PMD was 37 nmol/L (95% CI, 33–41) with significant heterogeneity among studies. Dose (slope: 0.006; P < 0.001), trial duration (slope: 0.21; P < 0.001), baseline serum 25(OH)D (slope: −0.19; P < 0.001), and age (slope: 0.42; P < 0.001) independently influenced vitamin D response. Similar results were found in studies with a mean baseline serum 25(OH)D <50 nmol/L. In subgroup analyses, the PMD was higher with doses ≥800 IU/d (39.3 nmol/L) after 6 to 12 mo (41.7 nmol/L), with baseline 25(OH)D <50 nmol/L (39.6 nmol/L), and in adults aged >80 y (40.5 nmol/L).ConclusionThis meta regression indicates that a higher increase in serum levels of 25(OH)D in adults is found with a dose of ≥800 IU/d, after at least 6 to 12 mo, and even when baseline 25(OH)D is low and in adults >80 y.     

The Canadian Home Total Parenteral Nutrition (HTPN) Registry: vitamin K supplementation and bone mineral density

Background: Vitamin K supplementation improves bone health, and its absence might be associated with low bone mineral density (BMD). The authors aim to assess vitamin K supplementation practices in Canadian home parenteral nutrition (HPN) programs and their relationship with BMD. Methods: This is a cross‐sectional study of 189 patients from the Canadian HPN registry. Results: All 189 patients studied received M.V.I.‐12, which does not contain vitamin K. Of those, 41.3% were supplemented with 10 mg of intravenous vitamin K (VK+) weekly, whereas the others did not receive vitamin K except via lipid emulsion (VK?). Short bowel syndrome accounted for 69% of VK+ and 46% of VK? patients. On univariate analysis, VK+ patients had substantially lower body mass index (BMI) and received lower bisphosphonate infusion than did VK?patients. There were no statistically significant differences in HPN calcium or lipid content, liver function test results, age, sex, or reason for HPN between the 2 groups. Patients who were VK+ had higher lumbar spine T scores and hip T scores than did VK?patients. General linear modeling analysis, adjusted for BMI, age, PN magnesium, PN phosphate, PN calcium, and bisphosphonate as possible predictors of BMD, showed a trend toward better hip T scores (P = .063) for VK+ patients compared with VK? patients. Conclusion: In HPN patients supplemented with vitamin K, the trend toward a better hip BMD compared with no supplementation suggests a role for vitamin K in preserving BMD. This requires further study.