Three doses of vitamin D, bone mineral density, and geometry in older women during modest weight control in a 1-year randomized controlled trial

A vitamin D deficient diet increases weight gain and compromises bone biomechanical properties without a reduction in BMD in adult female mice

Vitamin D contributes to the development and maintenance of bone. Evidence suggests vitamin D status can also alter energy balance and gut health. In young animals, vitamin D deficiency (VDD) negatively affects bone mineral density (BMD) and bone microarchitecture, and these effects may also occur due to chronic ethanol intake. However, evidence is limited in mature models, and addressing this was a goal of the current study. Seven-month-old female C57BL/6 mice (n = 40) were weight-matched and randomized to one of four ad libitum diets: control, alcohol (Alc), vitamin D deficient (0 IU/d), or Alc+VDD for 8 weeks. A purified (AIN-93) diet was provided with water or alcohol (10 %) ad libitum. Body weight and food intake were recorded weekly, and feces were collected at 0, 4, and 8 weeks. At the age of 9 months, intestinal permeability was assessed by oral gavage of fluorescein isothiocyanate-dextran. Thereafter, bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. The microarchitecture of the distal femur was assessed by micro-computed tomography and biomechanical properties were evaluated by cyclic reference point indentation. VDD did not affect BMD or most bone microarchitecture parameters, however, the polar moment of inertia (p < 0.05) was higher in the VDD groups compared to vitamin D sufficient groups. VDD mice also had lower whole bone water content (p < 0.05) and a greater average unloading slope (p < 0.01), and energy dissipated (p < 0.01), indicating the femur displayed a brittle phenotype. In addition, VDD caused a greater increase in energy intake (p < 0.05), weight gain (p < 0.05), and a trend for higher intestinal permeability (p = 0.08). The gut microbiota of the VDD group had a reduction in alpha diversity (p < 0.05) and a lower abundance of ASVs from Rikenellaceae, Clostridia_UCG-014, Oscillospiraceae, and Lachnospiraceae (p < 0.01). There was little to no effect of alcohol supplementation on outcomes. Overall, these findings suggest that vitamin D deficiency causes excess weight gain and reduces the biomechanical strength of the femur as indicated by the higher average unloading slope and energy dissipated without an effect on BMD in a mature murine model.

Vitamin D and Calcium in Osteoporosis, and the Role of Bone Turnover Markers: A Narrative Review of Recent Data from RCTs

Osteoporosis is a common disease, defined primarily by a low measured bone density, which is associated with an increased risk of fragility fractures. Low calcium intake and vitamin D deficiency seem to be positively correlated with the prevalence of osteoporosis. Although they are not suitable for the diagnosis of osteoporosis, the biochemical markers of bone turnover can be measured in serum and/or urine, enabling the assessment of the dynamic bone activity and the short-term effectiveness of the osteoporosis treatment. Calcium and vitamin D are essential for maintaining bone health. The aim of this narrative review is to summarize the effects of vitamin D and calcium supplementation separately and in combination, on bone density and circulating serum and blood plasma vitamin D, calcium, parathyroid hormone levels, markers of bone metabolism concentrations, and clinical outcomes, such as falls and osteoporotic fractures. We searched the PubMed online database to find clinical trials from the last five years (2016-April 2022). A total of 26 randomized clinical trials (RCTs) were included in this review. The present reviewed evidence suggests that vitamin D alone or in combination with calcium increases circulating 25(OH)D. Calcium with concomitant vitamin D supplementation, but not vitamin D alone, leads to an increase in BMD. In addition, most studies did not detect significant changes in circulating levels of plasma bone metabolism markers, nor in the incidence of falls. Instead, there was a decrease in blood serum PTH levels in the groups receiving vitamin D and/or Ca supplementation. The plasma vitamin D levels at the beginning of the intervention, and the dosing regimen followed, may play a role in the observed parameters. However, further study is needed to determine an appropriate dosing regimen for the treatment of osteoporosis and the role of bone metabolism markers.

Effect of supplemental vitamin D3 on bone mineral density: a systematic review and meta-analysis

Context

There is still controversy over the effect of vitamin D3 supplementation on bone health.

Objective

The effects of vitamin D3 supplementation on bone mineral density (BMD) and markers of bone turnover, as well as the dose-response relationship between vitamin D3 and bone health in adults, were evaluated.

Data Sources

The PubMed, Scopus, Cochrane, Web of Science, and AGRIS databases were searched for articles published through April 30, 2022. Thirty-nine of the 6409 records identified met the inclusion criteria

Data Extraction

Data were extracted from articles by 2 authors, and data extraction was cross-checked independently. A random-effects model was used to estimate the pooled effect size and the associated 95%CI for the effect of vitamin D3 for each outcome. A one-stage random-effects dose-response model was used to estimate the dose-response relationship between vitamin D3 supplementation and BMD.

Data Analysis

Results of meta-analysis showed a beneficial effect of vitamin D3 at the lumbar spine (standardized mean difference [SMD] = 0.06; 95%CI, 0.01–0.12) and femoral neck (SMD = 0.25; 95%CI, 0.09–0.41). Dose-response analysis revealed a linear relationship between vitamin D3 supplementation doses and BMD at the femoral neck, lumbar spine, and total hip sites. No significant effect of vitamin D3 supplementation on whole-body or total hip BMD was observed (P &gt; 0.05). Vitamin D3 supplementation significantly decreased BMD at both proximal and distal forearm (SMD = −0.16; 95%CI, −0.26 to −0.06). The variables of ethnicity, age, baseline 25-hydroxyvitamin D (25[OH]D), menopause status, vitamin D3 dosing frequency, and bone health status (P interaction = 0.02) altered the effect of vitamin D3 supplementation on BMD. Additionally, a nonlinear relationship between vitamin D3 supplement doses and markers of bone turnover was found.

Conclusion

A protective effect of vitamin D3 supplementation on BMD of the lumbar spine, femoral neck, and total hip is implicated.

Systematic Review Registration

PROSPERO registration number CRD42017054132.

Weight Loss Interventions and Skeletal Health in Persons with Diabetes

PURPOSE OF REVIEW

Weight loss is recommended for improving glycemic control and reducing cardiovascular risk factors in persons with diabetes. However, both diabetes and weight loss have been associated with detrimental skeletal health. This review aims to summarize recent study findings on the effects of lifestyle interventions for weight loss on skeletal health among persons with type 2 diabetes (T2D).

RECENT FINDINGS

A few large-scale observational studies have demonstrated an increased fragility fracture risk associated with weight loss among persons with T2D. Randomized control trials in persons with T2D also have shown that intentional lifestyle interventions for weight loss are associated with a greater decrease in bone mineral density (BMD) and an increase in the risk of fracture. The biological mechanisms underlying the compromised bone health during lifestyle interventions for weight loss are complex and not yet conclusive. However, there is evidence to suggest that bone loss and increased fracture risk during intentional weight loss may be mitigated by some intervention approaches, such as high protein intake, calcium supplementation, and resistance and balance training. There is still a lack of studies investigating the effects of different interventions for weight loss on skeletal health among persons with T2D. However, certain types of diet and physical activity intervention combined with bone monitoring and fracture risk prediction may help achieve weight loss goals and maintain skeletal health among persons with T2D during intentional weight loss.

Older Women who are Overweight or Obese Have Vertebral Abnormalities, Partially Degraded TBS, and BMD that Worsen with Weight Loss

Obesity is a risk factor for chronic diseases and moderate weight loss is generally recommended. Energy restriction results in the loss of hip bone mineral density (BMD) in older adults, but there is no consistent decline at the lumbar spine (LS), possibly due to vertebral abnormalities although this may also be dependent on the amount of weight loss. In this secondary analysis of weight loss trials investigating BMD and trabecular bone score (TBS) changes over 12-18 months, 92 postmenopausal women (60.8 ± 5.8 years; body mass index 32.7 ± 4.4 kg/m²) without osteoporosis, were divided into two groups: those who lost < 5% body weight (minimal) or ≥ 5% (moderate). Hip and LS-BMD and TBS were measured at baseline, 6 and 12-18 months. Exclusion of vertebral abnormalities (VE) was used to calculate BMD at the spine (LS-BMD-VE) using standard guidelines. Women lost 2.3 ± 2.4% and 8.5 ± 4.7% weight in the minimal and moderate weight loss groups, respectively. Over one third of the women had at least one vertebral abnormality or partially degraded TBS at baseline that worsened after weight loss, increasing to over 50% in this population (p < 0.05). TBS and hip BMD decreased with weight loss (p < 0.05), but LS-BMD did not decrease significantly. However, after excluding vertebral abnormalities, the LS-BMD-VE decreased in the entire population (p < 0.01), and by 1.7 ± 4.3% in the moderate weight loss group. This study suggests that older women without osteoporosis have vertebral abnormalities that obfuscated declines in BMD with weight loss, indicating that bone at the spine is further compromised.

Higher protein intake during caloric restriction improves diet quality and attenuates loss of lean body mass

OBJECTIVE

Higher protein intake during weight loss is associated with better health outcomes, but whether this is because of improved diet quality is not known. The purpose of this study was to examine how the change in self-selected protein intake during caloric restriction (CR) alters diet quality and lean body mass (LBM).

METHODS

In this analysis of pooled data from multiple weight loss trials, 207 adults with overweight or obesity were examined before and during 6 months of CR (approximately 10 food records/person). Body composition was measured by dual-energy x-ray absorptiometry. Diet quality was assessed using the Healthy Eating Index in 2 groups: lower (LP) and higher (HP) protein intake.

RESULTS

Participants (mean [SD], 54 [11] years; 29 [4] kg/m² ) lost 5.0% (5.4%) of weight. Protein intake was 79 (9) g/d (1.0 [0.2] g/kg/d) and 58 (6) g/d (0.8 [0.1] g/kg/d) in the HP and LP groups, respectively (p < 0.05), and there was an attenuated LBM (kilograms) loss in the HP (-0.6% [1.5%]) compared with the LP (-1.2% [1.4%]) group (p < 0.01). The increased Healthy Eating Index score in the HP compared with the LP group was attributed to greater total protein and green vegetable intake and reduced refined grain and added-sugar intake (p < 0.05).

CONCLUSIONS

Increasing dietary protein during CR improves diet quality and may be another reason for reduced LBM, but it requires further study.

Vitamin D biomarkers for Dietary Reference Intake development in children: a systematic review and meta-analysis

BACKGROUND

Circulating 25-hydroxyvitamin D [25(OH)D] has been the accepted vitamin D exposure/intake biomarker of choice within recent DRI exercises, but use of other vitamin D-related biomarkers as well as functional markers has been suggested. These may be of value in future vitamin D DRI exercises, such as the FAO/WHO's one for young children.

OBJECTIVES

To systematically review the usefulness of circulating 25(OH)D, parathyroid hormone (PTH), free and bioavailable 25(OH)D, C3-epimer of 25(OH)D, vitamin D3, 24,25-dihydroxyvitamin D [24,25(OH)2D], and bone turnover markers and calcium absorption as vitamin D biomarkers for DRI development in children.

METHODS

Methods included structured searches of published articles, full-text reviews, data extraction, quality assessment, meta-analysis, and random-effects meta-regression.

RESULTS

Fifty-nine vitamin D supplementation randomized controlled trials (RCTs) were included (39 in infants/children as the priority group and the remainder in adults since pediatric studies were absent/limited). Vitamin D supplementation significantly raised circulating 25(OH)D in infants and children, but the response was highly heterogeneous [weighted mean difference (WMD): 27.7 nmol/L; 95% CI: 22.9, 32.5; 27 RCTs; I2 = 93%]. Meta-regression suggested an increase by 1.7 nmol/L (95% CI: 0.7, 2.6) in serum 25(OH)D per each 100-IU increment in vitamin D intake (P = 0.0005). Vitamin D supplementation had a significant effect on circulating 24,25(OH)2D (WMD: 3.4 nmol/L; 95% CI: 2.4, 4.5; 13 RCTs; I2 = 95%), with a dose-response relation (+0.15 nmol/L per 100 IU; 95% CI: -0.01, 0.29). With circulating PTH, although there was a significant effect of vitamin D on WMD (P = 0.05), there was no significant dose-response relation (P = 0.32). Pediatric data were too limited in relation to the usefulness of the other biomarkers.

CONCLUSIONS

Circulating 25(OH)D may be a useful biomarker of vitamin D exposure/intake for DRI development in infants and children. Circulating 24,25(OH)2D also showed some promise, but further data are needed, especially in infants and children.

Total and free vitamin D metabolites in patients with primary hyperparathyroidism

PURPOSE

To evaluate total and free vitamin D metabolites and hormone-to-prohormone [1,25(OH)₂D/25(OH)D] "activation ratio" in PHPT patients with low or insufficient vitamin D status.

METHODS

Thirty female patients with primary hyperparathyroidism (PHPT) and 30 age and body mass index (BMI) matched healthy controls were enrolled. Serum levels of calcium, intact parathyroid hormone (iPTH), vitamin D binding protein (DBP), albumin, total 25(OH)D and 1,25(OH)₂D were measured. The activation ratio of vitamin D was calculated as total 1,25(OH)₂D/25(OH)D. Calculated serum-free 25(OH)D and 1,25(OH)₂D levels were also reported.

RESULTS

Compared to the control subject, patients with PHPT had a lower total 25(OH)D and DBP levels (p < 0.001). The serum concentration of free 25(OH)D and total 1,25(OH)₂D were similar between the two groups; but free 1,25(OH)₂D levels were about 26% higher in the PHPT patients compared to controls (p < 0.001). PHPT patients had a significantly higher activation ratio (p < 0.01), although their total 25(OH)D were lower than controls. The free (but not total) 1,25(OH)₂D level was inversely correlated with DBP (p < 0.01). Both free 1,25(OH)₂D levels and activation ratio were positively correlated with iPTH and calcium levels (p < 0.01). The activation ratio was highly correlated with levels of total vitamin D stores and free vitamin D metabolites (p < 0.001).

CONCLUSION

Patients with PHPT had significantly higher free 1,25(OH)₂D levels and activation ratio compared to control subjects. We suggest that levels of free vitamin D metabolites and vitamin D activation ratio may provide additional values for the diagnosis and therapeutic choices in these patient populations with compromised vitamin D status.

Protein, Calcium, Vitamin D Intake and 25(OH)D Status in Normal Weight, Overweight, and Obese Older Adults: A Systematic Review and Meta-Analysis

The aging process is often accompanied by increase in body weight. Older adults with overweight or obesity might have an overconsumption in energy that is accompanied by inadequate intake of protein, vitamin D, and calcium. It is unclear if intake of protein and vitamin D and calcium is sufficient in older adults with overweight/obesity, and whether it differs from older adults with normal weight, since a recent overview of the literature review is lacking. Therefore, we systematically analyzed the current evidence on differences in nutrient intake/status of protein, vitamin D and calcium between older adults with different body mass index (BMI) categories. Randomized controlled trials and prospective cohort studies were identified from PubMed and EMBASE. Studies reporting nutrient intake/status in older adults aged ≥50 years with overweight/obesity and studies comparing between overweight/obesity and normal weight were included. Nutrient intake/status baseline values were reviewed and when possible calculated for one BMI category (single-group meta-analysis), or compared between BMI categories (meta-analysis). Nutrient intake/status was compared with international recommendations. Mean protein (N = 8) and calcium intake (N = 5) was 0.98 gram/kilogram body weight/day (g/kg/d) [95% Confidence Interval (CI) 0.89-1.08] and 965 mg [95% CI: 704-1225] in overweight/obese. Vitamin D intake was insufficient in all BMI categories (N = 5). The pooled mean for vitamin D intake was 6 ug [95% CI 4-9]. For 25(OH)D, the pooled mean was 54 nmol/L [95% CI 45-62], 52 nmol/L [95% CI 46-58], and 48 nmol/l [95% CI 33-62] in normal (N = 7), combined overweight and obese (N = 12), and obese older adults (N = 4), respectively. In conclusion, older adults with overweight and obesity have a borderline sufficient protein and sufficient calcium intake, but insufficient vitamin D intake. The 25(OH)D concentration is deficient for the obese older adults.

Genetically determined SCFA concentration modifies the association of dietary fiber intake with changes in bone mineral density during weight loss: The Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial

BACKGROUND

SCFAs are involved in regulation of body weight and bone health.

OBJECTIVES

We aimed to examine whether genetic variations related to butyrate modified the relation between dietary fiber intake and changes in bone mineral density (BMD) in response to weight-loss dietary interventions.

METHODS

In the 2-y Preventing Overweight Using Novel Dietary Strategies trial, 424 participants with BMD measured by DXA scan were randomly assigned to 1 of 4 diets varying in macronutrient intakes. A polygenic score (PGS) was calculated based on 7 genetic variants related to the production of butyrate for 370 of the 424 participants.

RESULTS

SCFA PGS significantly modified the association between baseline dietary fiber intake and sex on 2-y changes in whole-body BMD (P-interaction = 0.049 and 0.008). In participants with the highest tertile of SCFA PGS, higher dietary fiber intake was related to a greater increase in BMD (β:  0.0022; 95% CI: 0.0009, 0.0035; P = 0.002), whereas no such association was found for participants in the lower tertiles. In the lowest tertiles of SCFA PGS, men showed a significant increase in whole-body BMD (β: 0.0280; 95% CI: 0.0112, 0.0447; P = 0.002) compared with women. In the highest tertile, no significant difference was found for the change in BMD between men and women.

CONCLUSIONS

Our data indicate that genetic variants related to butyrate modify the relations of dietary fiber intake and sex with long-term changes in BMD in response to weight-loss diet interventions.

Postmenopausal osteoporosis coexisting with other metabolic diseases: Treatment considerations

In postmenopausal women, osteoporosis may coexist with other metabolic diseases, including, but not limited to, obesity, diabetes, nonalcoholic fatty liver disease (NAFLD), dyslipidemia and cardiovascular disease (CVD). This association may lie beyond simple coincidence owing to high prevalence of all these diseases, especially in the aging population, as common pathogenetic mechanisms between them and osteoporosis may exist. In this context, anti-osteoporotic medications may affect the pathogenesis of some of these metabolic diseases; this is an important consideration when selecting the most appropriate medication for osteoporotic patients with coexistent metabolic diseases. Conversely, some current or emerging medications for metabolic diseases adversely affect bone metabolism and, if possible, should be avoided in women with postmenopausal osteoporosis. The main aim of this review is to summarize the evidence on anti-osteoporotic treatment in postmenopausal women with concomitant metabolic diseases, i.e. obesity, diabetes, NAFLD, dyslipidemia and CVD. The secondary aim is to present data on the effect of current or emerging medication for metabolic diseases on bone metabolism of postmenopausal women. Deeper understanding of the underlying links between osteoporosis and metabolic diseases may have clinical implications. However, mechanistic studies are needed to elucidate the potential pathophysiological links, as well as clinical trials in women with postmenopausal osteoporosis coexisting with specific metabolic diseases; these may guide clinical practice in the future for the selection of the best anti-osteoporotic medication for each patient with specific metabolic diseases.

Response of Vitamin D after Magnesium Intervention in a Postmenopausal Population from the Province of Granada, Spain

Menopause is a stage of hormonal imbalance in women which, in addition to other physiopathological consequences, poses a risk of deficiency of key micronutrients such as magnesium and vitamin D. A study was made of the influence of a magnesium intervention upon vitamin D status in a postmenopausal population from the province of Granada (Spain). Fifty-two healthy postmenopausal women between 44–76 years of age were included. Two randomized groups—placebo and magnesium (500 mg/day)—were treated during eight weeks. Nutrient intake was assessed using questionnaires based on 72-h recall. Vitamin D was analyzed by liquid chromatography—tandem mass spectrometry. Baseline vitamin D proved deficient in over 80% of the subjects. The administration of magnesium resulted in significantly increased vitamin D levels in the intervention group versus the controls (p < 0.05). Magnesium supplementation improved vitamin D status in the studied postmenopausal women.

Association between Visceral Fat and Bone Mineral Density in Both Male and Female Patients with Adult Growth Hormone Deficiency

Aim

Adult growth hormone deficiency (AGHD) is associated with an increased risk of fractures. The interactions between various body composition and bone are known to be complex in nature. However, very few studies have examined this crosstalk in AGHD. In this study, we sought to investigate the relationship between various parameters of body composition and bone mineral density (BMD) as well as determine the role of visceral fat in determining the bone mass in patients with AGHD.

Methods

We conducted a cross-sectional study on 57 patients with AGHD. Anthropometry, biochemistry, and analysis of body composition and BMD were performed according to standard protocols. Male and female patients were classified into those with osteoporosis and those without osteoporosis (normal subjects and patients with osteopenia). Further, we analyzed the correlation between the BMD and measurements obtained for various body composition parameters in male and female AGHD patients.

Results

Our findings indicated that among female AGHD patients, those with osteoporosis had a significantly higher levels of fat mass (FM) and visceral adipose tissue mass (VATM) (both, P < 0.05) than those without osteoporosis. Further, Pearson correlation analysis showed that the values of age, body mass index (BMI), FM, and VATM correlated negatively with BMD in women with AGHD (all P < 0.05); however, this association was not noted in men. After adjusting for the other covariates, VATM was found to be independently correlated with the BMD in female patients with AGHD.

Conclusions

A close correlation was noted between VATM and BMD in female patients with AGHD.

Administration of Denosumab Preserves Bone Mineral Density at the Knee in Persons With Subacute Spinal Cord Injury: Findings From a Randomized Clinical Trial

Persons with neurologically motor-complete spinal cord injury (SCI) have a marked loss of bone mineral density (BMD) of the long bones of the lower extremities, predisposing them to fragility fractures, especially at the knee. Denosumab, a commercially available human monoclonal IgG antibody to receptor activator of nuclear factor-κB ligand (RANKL), may provide an immunopharmacological solution to the rapid progressive deterioration of sublesional bone after SCI. Twenty-six SCI participants with subacute motor-complete SCI were randomized to receive either denosumab (60 mg) or placebo at baseline (BL), 6, and 12 months. Areal bone mineral density (aBMD) by dual energy x-ray absorptiometry (DXA) at 18 months at the distal femur was the primary outcome and aBMD of the proximal tibia and hip were the secondary outcomes analyzed in 18 of the 26 participants (denosumab, n = 10 and placebo, n = 8). The metrics of peripheral QCT (pQCT) were the exploratory outcomes analyzed in a subsample of the cohort (denosumab, n = 7 and placebo n = 7). The mean aBMD (±95% CI) for the denosumab versus the placebo groups demonstrated a significant group × time interactions for the following regions of interest at BL and 18 months: distal femoral metaphysis = mean aBMD 1.187; 95% CI, 1.074 to 1.300 and mean aBMD 1.202; 95% CI, 1.074 to 1.329 versus mean aBMD 1.162; 95% CI, 0.962 to 1.362 and mean aBMD 0.961; 95% CI, 0.763 to 1.159, respectively (p < 0.001); distal femoral epiphysis = mean aBMD 1.557; 95% CI, 1.437 to 1.675 and mean aBMD 1.570; 95% CI, 1.440 to 1.700 versus mean aBMD 1.565; 95% CI, 1.434 to 1.696 and mean aBMD 1.103; 95% CI, 0.898 to 1.309, respectively (p = 0.002); and proximal tibial epiphysis = mean aBMD 1.071; 95% CI, 0.957 to 1.186 and mean aBMD 1.050; 95% CI, 0.932 to 1.168 versus mean aBMD 0.994; 95% CI, 0.879 to 1.109 and mean aBMD 0.760; 95% CI, 0.601 to 0.919, respectively (p < 0.001). Analysis of pQCT imaging revealed a continued trend toward significantly greater loss in total volumetric BMD (vBMD) and trabecular vBMD at the 4% distal tibia region, with a significant percent loss for total bone mineral content. Thus, at 18 months after acute SCI, our findings show that denosumab maintained aBMD at the knee region, the site of greatest clinical relevance in the SCI population. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Lower total 25-hydroxyvitamin D but no difference in calculated or measured free 25-hydroxyvitamin D serum levels in patients with primary hyperparathyroidism

To evaluate the measured free 25-hydroxyvitamin D [25(OH)D] levels in patients with hyperparathyroidism (PHPT) and healthy controls. Eighty patients with PHPT(n = 40) and age and BMI matched controls (n = 40) were examined. Serum levels of total or free 25(OH)D, vitamin D binding protein (DBP), intact parathyroid hormone (iPTH) and calcium were measured. There was no significant difference in age (61.2 ± 11.9 vs 60.2 ± 7.0 years) and BMI (30.0 ± 6.1 vs 30.0 ± 2.2 kg/m²) between PHPT patients and healthy subjects. Levels of total 25(OH)D were about 20 % lower in PHPT patients (26.4 ± 7.7 ng/mL) compared to controls (31.0 ± 7.8 ng/mL, P < 0.05). There were no significant differences in calculated or measured free 25(OH)D levels between PHPT patients (4.9 ± 1.8 or 4.9 ± 1.6 pg/mL, respectively) and control subjects (5.1 ± 1.2 or 5.3 ± 1.6 pg/mL, respectively). Levels of free 25(OH)D were positively associated with levels of total 25(OH)D (r = 0.28, P < 0.05) but negatively correlated with iPTH and calcium levels (r=-0.22 and -0.23 respectively, P < 0.05). Serum total 25(OH)D levels were lower but the calculated or measured free 25(OH)D levels in patients with PHPT did not differ from healthy subjects. We suggest that total 25(OH)D levels may not reflect true vitamin D nutritional status in patients with PHPT.

Three Doses of Vitamin D and Cognitive Outcomes in Older Women: A Double-Blind Randomized Controlled Trial

Vitamin D may affect cognitive performance, but previous studies are either short term or observational. We conducted a randomized controlled trial of vitamin D supplementation on domain-specific cognitive measures in postmenopausal women. Overweight/obese women with serum 25-hydroxyvitamin D (25OHD) levels less than 30 ng/mL were recruited. Vitamin D3 supplementation (600, 2,000, or 4,000 IU/d) was randomly assigned in a double-blinded manner for 1 year. Serum 25-hydroxyvitamin D, osteocalcin (total and undercarboxylated), amyloid beta, parathyroid hormone, and estradiol were analyzed before and after supplementation. Cognitive tests were administered after treatment. The women (58 ± 6 years; body mass index, 30.0 ± 3.5 kg/m2) had a baseline serum 25-hydroxyvitamin D level of 22.6 ± 5.8 ng/mL that increased to 30.2 ± 5.6, 36.0 ± 4.9, and 40.8 ± 7.0 ng/mL in the 600, 2,000, and 4,000 IU/d groups, respectively (p < .001). Participants taking 2,000 IU/d compared to other doses performed better in learning and memory tests (p < .05), yet the 4,000 IU/d group had a slower reaction time compared to the 600 IU/d group. Multiple regression indicated that serum undercarboxylated osteocalcin predicted tasks associated with reaction time and executive function, whereas body mass index and parathyroid hormone negatively predicted reaction time and executive function (p ≤ .01). These data suggest that vitamin D has differential effects on domain-specific cognitive measures and that a higher dose may negatively affect reaction time.

Vitamin D, genetics, and bone mineral density during weight loss

PURPOSE OF REVIEW

The current review is to summarize the recent progress in the research of the relation between vitamin D and bone mineral density (BMD) during weight-loss interventions, and describe how genetic factors interact with weight-loss interventions on changes in bone health.

RECENT FINDINGS

Obesity has shown to be a protective factor for bone health, whereas the relation between weight loss and BMD has yet to be well established. Although beneficial on a variety of metabolic outcomes, weight-loss interventions, such as dietary modifications and surgical treatment, showed adverse effects on bone health in some studies. Despite the biological plausibility for a role of vitamin D in promoting bone health, current evidence does not consistently support the connection between changes in circulating vitamin D levels and BMD during weight loss, partly because of insufficient vitamin D levels during weight loss. Genome-wide association studies have identified genetic variants related to the blood levels of vitamin D; and emerging evidence suggests that dietary intakes may modify the relationship between genetically determined circulating vitamin D levels and change in BMD in response to weight-loss diets.

SUMMARY

The relations of changes in circulating vitamin D levels with bone health during weight-loss interventions remain to be established, and the role of genetic factors would be considered in future investigations.

Effects of Dietary Protein Quantity on Bone Quantity following Weight Loss: A Systematic Review and Meta-analysis

Research supports the hypothesis that higher total protein intake during weight loss promotes retention of lean soft tissue, but the effect of dietary protein quantity on bone mass, a lean hard tissue, is inconsistent. The purpose of this systematic review and meta-analysis was to assess the effect of dietary protein quantity [higher protein (HP): ≥25% of energy from protein or ≥1.0 g · kg body wt-1 · d-1; normal protein (NP): <25% of energy from protein or <1.0 g · kg body wt-1 · d-1] on changes in bone mineral density (BMD) and content (BMC; total body, lumbar spine, total hip, femoral neck) following a prescribed energy restriction. We hypothesized that an HP diet would attenuate the loss of BMD/BMC following weight loss in comparison to an NP diet. Two researchers systematically and independently screened 2366 publications from PubMed, Cochrane, Scopus, CINAHL, and Web of Science Core Collection and extracted data from 34 qualified publications. Inclusion criteria included the following: 1) healthy subjects ≥19 y; 2) a prescribed energy restriction; 3) measurements of total protein intake, BMD, and BMC; and 4) an intervention duration of ≥3 mo. Data from 10 of the 34 publications with 2 groups of different total protein intakes were extracted and used to conduct a random-effects model meta-analysis. A majority of publications (59%) showed a decrease in bone quantity following active weight loss, regardless of total protein intake. Statistically, the loss of total BMD (P = 0.016; weighted mean difference: +0.006 g/cm2; 95% CI: 0, 0.011 g/cm2) and lumbar spine BMD (P = 0.019; weighted mean difference: +0.017 g/cm2; 95% CI: 0.001, 0.033 g/cm2) was attenuated with an HP versus an NP weight-loss diet. However, the clinical significance is questionable given the modest weighted mean difference and study duration. Higher total protein intake does not exacerbate but may attenuate the loss of bone quantity following weight loss.

Effect of High-Dose Vitamin D Supplementation on Volumetric Bone Density and Bone Strength: A Randomized Clinical Trial

Importance

Few studies have assessed the effects of daily vitamin D doses at or above the tolerable upper intake level for 12 months or greater, yet 3% of US adults report vitamin D intakes of at least 4000 IU per day.

Objective

To assess the dose-dependent effect of vitamin D supplementation on volumetric bone mineral density (BMD) and strength.

Design, Setting, and Participants

Three-year, double-blind, randomized clinical trial conducted in a single center in Calgary, Canada, from August 2013 to December 2017, including 311 community-dwelling healthy adults without osteoporosis, aged 55 to 70 years, with baseline levels of 25-hydroxyvitamin D (25[OH]D) of 30 to 125 nmol/L.

Interventions

Daily doses of vitamin D3 for 3 years at 400 IU (n = 109), 4000 IU (n = 100), or 10 000 IU (n = 102). Calcium supplementation was provided to participants with dietary intake of less than 1200 mg per day.

Main Outcomes and Measures

Co-primary outcomes were total volumetric BMD at radius and tibia, assessed with high resolution peripheral quantitative computed tomography, and bone strength (failure load) at radius and tibia estimated by finite element analysis.

Results

Of 311 participants who were randomized (53% men; mean [SD] age, 62.2 [4.2] years), 287 (92%) completed the study. Baseline, 3-month, and 3-year levels of 25(OH)D were 76.3, 76.7, and 77.4 nmol/L for the 400-IU group; 81.3, 115.3, and 132.2 for the 4000-IU group; and 78.4, 188.0, and 144.4 for the 10 000-IU group. There were significant group × time interactions for volumetric BMD. At trial end, radial volumetric BMD was lower for the 4000 IU group (-3.9 mg HA/cm3 [95% CI, -6.5 to -1.3]) and 10 000 IU group (-7.5 mg HA/cm3 [95% CI, -10.1 to -5.0]) compared with the 400 IU group with mean percent change in volumetric BMD of -1.2% (400 IU group), -2.4% (4000 IU group), and -3.5% (10 000 IU group). Tibial volumetric BMD differences from the 400 IU group were -1.8 mg HA/cm3 (95% CI, -3.7 to 0.1) in the 4000 IU group and -4.1 mg HA/cm3 in the 10 000 IU group (95% CI, -6.0 to -2.2), with mean percent change values of -0.4% (400 IU), -1.0% (4000 IU), and -1.7% (10 000 IU). There were no significant differences for changes in failure load (radius, P = .06; tibia, P = .12).

Conclusions and Relevance

Among healthy adults, treatment with vitamin D for 3 years at a dose of 4000 IU per day or 10 000 IU per day, compared with 400 IU per day, resulted in statistically significant lower radial BMD; tibial BMD was significantly lower only with the 10 000 IU per day dose. There were no significant differences in bone strength at either the radius or tibia. These findings do not support a benefit of high-dose vitamin D supplementation for bone health; further research would be needed to determine whether it is harmful.

Trial Registration

ClinicalTrials.gov Identifier: NCT01900860.

Adverse events from large dose vitamin D supplementation taken for one year or longer

In recent years, clinical trials increasingly have given large doses of vitamin D supplements to investigate possible health benefits beyond bone at high 25-hydroxyvitamin D levels. However, there are few publications on the safety of high-dose vitamin D given long term. The study objective was to investigate the cumulative relative risk (RR) of total adverse events, kidney stones, hypercalcemia and hypercalciuria from ≥2800 IU/d vitamin D₂ or D₃ supplementation, followed for one year or more in randomized controlled trials (RCTs). A systematic review was conducted in Medline Ovid, EMBASE and Cochrane in March 2018 to update results of studies published since a previous review in October 2015. RCTs were included if they gave vitamin D₂ or D₃ at ≥2800 IU/d for at least one year and reported on total adverse events or at least one calcium-related adverse event. There were a total of 32 studies that met the inclusion criteria. Of these, only 15 studies (3150 participants) reported one or more event of the outcomes of interest. Long-term high-dose vitamin D supplementation did not increase total adverse events compared to placebo in 1731 participants from 10 studies (RR = 1.05; 95% CI = 0.88, 1.24; p = 0.61), nor kidney stones in 1336 participants from 5 studies (RR = 1.26; 95% CI = 0.35, 4.58; p = 0.72). However, there was a trend for vitamin D to increase risk of hypercalcemia in 2598 participants from 10 studies (RR = 1.93; 95% CI = 1.00, 3.73; p = 0.05); while its effect on hypercalciuria in only 276 participants from 3 studies was inconclusive (RR = 1.93; 95% CI = 0.83, 4.46; p = 0.12). In conclusion, one year or longer supplementation with a large daily, weekly or monthly dose of vitamin D₂ /D₃ did not significantly increase a risk of total adverse events or kidney stones, although there was a trend towards increased hypercalcemia, and possibly for hypercalciuria.

A systematic review and meta-analysis of the response of serum 25-hydroxyvitamin D concentration to vitamin D supplementation from RCTs from around the globe

BACKGROUND/OBJECTIVES

Optimal doses of vitamin D (VitD) supplement in different populations are unclear. We aim to evaluate the relationship between VitD supplementation and post-intervention serum 25-hydroxyvitamin D [25(OH)D] concentration, to provide a recommended dosage of VitD for achieving an optimal 25(OH)D concentration for different populations.

SUBJECTS/METHODS

Literature search was conducted in Embase, etc. Randomized controlled trials about VitD supplemental intakes and their effect on 25(OH)D concentration were enrolled. The effect on 25(OH)D concentration between different supplementation doses in each population group was compared by meta-analysis. Multivariate meta-regression model is utilized to establish reference intake dosage of VitD.

RESULTS

A total of 136 articles were included about children (3-17 years), adults (18-64 years), postmenopausal women, the elderly ( >64 years), pregnant, or lactating women. Overall, intervention groups obtained higher 25(OH)D concentration than controls and there was obvious dose-response effect between intake dose and 25(OH)D concentration. Baseline 25(OH)D concentration and age were significant indicators for 25(OH)D concentration. To reach sufficient 25(OH)D concentration (75 nmol/L), the recommended VitD supplemental intakes was 1340 and 2250 IU/day for children and pregnant women, 2519 and 797 IU/day for European adults aged 18-64 and 65-85 years, 729, 2026, and 1229 IU/day for adults in North America, Asia and Middle East and Africa, respectively.

CONCLUSIONS

Regional- and age-specific recommended dosages of VitD supplements for population to achieve optimal 25(OH)D concentrations have been suggested.

Vitamin D supplementation in obesity and during weight loss: A review of randomized controlled trials

Vitamin D deficiency is common in obese individuals and during weight loss. The recommended vitamin D doses in this specific population are higher than for healthy adults. We reviewed vitamin D supplementation trials in obesity, and during medical or surgical weight loss, and report the effects on 25-hydroxyvitamin D [25(OH)D] concentrations and other relevant outcomes. We conducted a systematic search in PubMed, Medline, Embase and the Cochrane library for relevant randomized controlled trials (RCTs) of oral vitamin D supplementation for at least 3 months in obese individuals without weight loss (OB), and those on medical weight loss (MWL) (2010-2018), and following bariatric surgery (Bar S) (without time restriction). Two reviewers screened the identified citations in duplicate and independently and performed full text screening. One reviewer completed data extraction. We identified 13 RCTs in OB, 6 in MWL and 7 in Bar S. Mean baseline 25(OH)D concentrations ranged between 7 and 27 ng/ml in OB, 15-29 ng/ml in MWL and 15-24 ng/ml in Bar S. In OB (Total N 2036 participants), vitamin D doses of 1600-4000 IU/d increased mean 25(OH)D concentrations to ≥30 ng/ml. Based on three trials during MWL (Total N 359 participants), vitamin D doses of 1200-4600 IU/d for 12 months increased 25(OH)D concentration to ≥30 ng/ml. In Bar S (Total N 615 participants), doses ≥2000 IU/d were needed to reach 30 ng/ml. The change in 25(OH)D concentration was inversely proportional to the administered dose, and to BMI and baseline level with doses of 600-3000 IU/day. With these doses, the change in 25(OH)D concentration [Δ25(OH)D] per 100 IU/d was 0.5-1.2 ng/ml. Three trials assessed bone mineral density as a primary outcome, but only one of them showed a protective effect of vitamin D against bone loss at all sites post-Bar S. There was no effect of vitamin D on weight loss. Data on extra-skeletal parameters, namely glycemic and vascular indices were mostly identified in OB, and findings were inconsistent. In conclusion, Vitamin D doses ≥1600-2000 IU/d may be needed to reach a 25(OH)D concentration of 30 ng/ml in obese individuals and following bariatric surgery. The optimal concentration in this population is unknown, and whether the above doses protect against weight loss induced bone loss and fractures still needs to be confirmed. There is no clear evidence for a beneficial effect of vitamin D supplementation on cardio-metabolic parameters in obese individuals, and data on such parameters with weight loss are very scarce. Well-designed long term RCTs assessing the effect of vitamin D supplementation during weight loss on patient important outcomes are needed.

25-Hydroxyvitamin D and Vitamin D Binding Protein Levels in Patients With Primary Hyperparathyroidism Before and After Parathyroidectomy

Objective: To evaluate vitamin D binding protein and free 25-hydroxyvitamin D [25(OH)D] levels in healthy controls compared to primary hyperparathyroidism (PHPT) patients, and to examine PHPT before and after surgery. Methods: Seventy-five PHPT patients and 75 healthy age, gender, and body mass index (BMI) -matched control subjects were examined. In addition, 25 PHPT patients underwent parathyroidectomy and had a 3-month follow up visit. Levels of total and free 25(OH)D, DBP, and intact parathyroid hormone (iPTH) were determined before and 3 months after surgery. Results: There was no significant difference in age and BMI between PHPT patients and controls. Levels of 25(OH)D and DBP were lower in PHPT patients compared to controls (p < 0.01). There was no significant difference in calculated free and bioavailable 25(OH)D levels between PHPT patients and controls. Calcium and iPTH levels decreased to normal but DBP and DBP-bound-25(OH)D increased (P < 0.001) after parathyroidectomy. Levels of DBP were inversely correlated with iPTH (r = -0.406, P < 0.001) and calcium levels (r = -0.423, P < 0.001). Conclusion: Serum DBP levels were lower in patients with PHPT and parathyroidectomy restored DBP levels. We suggest that lower DBP levels is one of contributing mechanisms of low total 25(OH)D in PTHP patients and the total 25(OH)D levels might not reflect true vitamin D status in PHPT patients.

Effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis

BACKGROUND

The effects of vitamin D on fractures, falls, and bone mineral density are uncertain, particularly for high vitamin D doses. We aimed to determine the effect of vitamin D supplementation on fractures, falls, and bone density.

METHODS

In this systematic review, random-effects meta-analysis, and trial sequential analysis, we used findings from literature searches in previously published meta-analyses. We updated these findings by searching PubMed, Embase, and Cochrane Central on Sept 14, 2017, and Feb 26, 2018, using the search term "vitamin D" and additional keywords, without any language restrictions. We assessed randomised controlled trials of adults (>18 years) that compared vitamin D with untreated controls, placebo, or lower-dose vitamin D supplements. Trials with multiple interventions (eg, co-administered calcium and vitamin D) were eligible if the study groups differed only by use of vitamin D. We excluded trials of hydroxylated vitamin D analogues. Eligible studies included outcome data for total or hip fractures, falls, or bone mineral density measured at the lumbar spine, total hip, femoral neck, total body, or forearm. We extracted data about participant characteristics, study design, interventions, outcomes, funding sources, and conflicts of interest. The co-primary endpoints were participants with at least one fracture, at least one hip fracture, or at least one fall; we compared data for fractures and falls using relative risks with an intention-to-treat analysis using all available data. The secondary endpoints were the percentage change in bone mineral density from baseline at lumbar spine, total hip, femoral neck, total body, and forearm.

FINDINGS

We identified 81 randomised controlled trials (n=53 537 participants) that reported fracture (n=42), falls (n=37), or bone mineral density (n=41). In pooled analyses, vitamin D had no effect on total fracture (36 trials; n=44 790, relative risk 1·00, 95% CI 0·93-1·07), hip fracture (20 trials; n=36 655, 1·11, 0·97-1·26), or falls (37 trials; n=34 144, 0·97, 0·93-1·02). Results were similar in randomised controlled trials of high-dose versus low-dose vitamin D and in subgroup analyses of randomised controlled trials using doses greater than 800 IU per day. In pooled analyses, there were no clinically relevant between-group differences in bone mineral density at any site (range -0·16% to 0·76% over 1-5 years). For total fracture and falls, the effect estimate lay within the futility boundary for relative risks of 15%, 10%, 7·5%, and 5% (total fracture only), suggesting that vitamin D supplementation does not reduce fractures or falls by these amounts. For hip fracture, at a 15% relative risk, the effect estimate lay between the futility boundary and the inferior boundary, meaning there is reliable evidence that vitamin D supplementation does not reduce hip fractures by this amount, but uncertainty remains as to whether it might increase hip fractures. The effect estimate lay within the futility boundary at thresholds of 0·5% for total hip, forearm, and total body bone mineral density, and 1·0% for lumbar spine and femoral neck, providing reliable evidence that vitamin D does not alter these outcomes by these amounts.

INTERPRETATION

Our findings suggest that vitamin D supplementation does not prevent fractures or falls, or have clinically meaningful effects on bone mineral density. There were no differences between the effects of higher and lower doses of vitamin D. There is little justification to use vitamin D supplements to maintain or improve musculoskeletal health. This conclusion should be reflected in clinical guidelines.

FUNDING

Health Research Council of New Zealand.