How vitamin D works on bone

Chronic kidney disease mineral bone disorder in childhood and young adulthood: a 'growing' understanding

Chronic kidney disease (CKD) mineral and bone disorder (MBD) comprises a triad of biochemical abnormalities (of calcium, phosphate, parathyroid hormone and vitamin D), bone abnormalities (turnover, mineralization and growth) and extra-skeletal calcification. Mineral dysregulation leads to bone demineralization causing bone pain and an increased fracture risk compared to healthy peers. Vascular calcification, with hydroxyapatite deposition in the vessel wall, is a part of the CKD-MBD spectrum and, in turn, leads to vascular stiffness, left ventricular hypertrophy and a very high cardiovascular mortality risk. While the growing bone requires calcium, excess calcium can deposit in the vessels, such that the intake of calcium, calcium- containing medications and high calcium dialysate need to be carefully regulated. Normal physiological bone mineralization continues into the third decade of life, many years beyond the rapid growth in childhood and adolescence, implying that skeletal calcium requirements are much higher in younger people compared to the elderly. Much of the research into the link between bone (de)mineralization and vascular calcification in CKD has been performed in older adults and these data must not be extrapolated to children or younger adults. In this article, we explore the physiological changes in bone turnover and mineralization in children and young adults, the pathophysiology of mineral bone disease in CKD and a potential link between bone demineralization and vascular calcification.

Genetic evidence of the causal relationship between chronic liver diseases and musculoskeletal disorders

BACKGROUND

Chronic liver diseases constitute a major global public health burden, posing a substantial threat to patients' daily lives and even survival due to the potential development of musculoskeletal disorders. Although the relationship between chronic liver diseases and musculoskeletal disorders has received extensive attention, their causal relationship has not been comprehensively and systematically investigated.

METHODS

This study aimed to assess the causal relationships between viral hepatitis, primary biliary cholangitis, primary sclerosing cholangitis (PSC), liver cirrhosis, and hepatocellular carcinoma (HCC) with osteoporosis, osteoarthritis, and sarcopenia through bidirectional Mendelian randomization (MR) research. The traits related to osteoporosis and osteoarthritis included both overall and site-specific phenotypes, and the traits linked to sarcopenia involved indicators of muscle mass and function. Random-effect inverse-variance weighted (IVW), weighted median, MR-Egger, and Causal Analysis Using the Summary Effect Estimates were used to evaluate causal effects, with IVW being the main analysis method. To enhance robustness, sensitivity analyses were performed using Cochran's Q test, MR-Egger intercept, MR-PRESSO global test, funnel plots, leave-one-out analyses, and latent causal variable model.

RESULTS

The forward MR analysis indicated that PSC can reduce forearm bone mineral density (beta = - 0.0454, 95% CI - 0.0798 to - 0.0110; P = 0.0098) and increase the risk of overall osteoarthritis (OR = 1.012, 95% CI 1.002-1.022; P = 0.0247), while HCC can decrease grip strength (beta = - 0.0053, 95% CI - 0.008 to - 0.0025; P = 0.0002). The reverse MR analysis did not find significant causal effects of musculoskeletal disorders on chronic liver diseases. Additionally, no heterogeneity or pleiotropy was detected.

CONCLUSIONS

These findings corroborate the causal effects of PSC on osteoporosis and osteoarthritis, as well as the causal impact of HCC on sarcopenia. Thus, the implementation of comprehensive preventive measures is imperative for PSC and HCC patients to mitigate the risk of musculoskeletal disorders, ultimately improving their quality of life.

Nutritional assessment of women with celiac disease compared to the general population

BACKGROUND & AIMS

The nutritional quality of a gluten-free diet is debated because of the elimination of grains that are important sources of nutrients. The aim of this cross-sectional study was to perform a nutritional assessment in treated women with celiac disease and ongoing symptoms, and compare dietary intake with a healthy reference group (Norkost 3).

METHODS

Celiac disease patients with biopsy confirmed mucosal healing, but persistent gastrointestinal symptoms, were included from an ongoing clinical trial. Nutritional assessment included anthropometrics, blood samples and dietary intake obtained by two 24 h recalls. Dietary intake in celiac women was compared with dietary intake in healthy women (Norkost 3). Two sample t-test was used for comparison of CeD and Norkost 3 women. Adjustment for age, BMI, education and smoking, by use of multiple linear regression analysis, did not change the results.

RESULTS

In total, 59 women with celiac disease and 925 women that participated in Norkost 3 were included, with a mean age of 45 years in both groups. Women with celiac disease had a higher proportion of energy (E%) from fat (39 vs 34%, P < 0.001) and saturated fat (15 vs 13%, P = 0.01), a lower E% from protein (16 vs 18%, P = 0.01) and a lower intake of dietary fiber (19 vs 22 g, P = 0.002) compared to Norkost 3 women. Women with celiac disease had a lower intake of bread, fruit and milk, and a higher intake of cereals and cheese compared to Norkost 3 women. The average requirement was not met for several micronutrients, but blood analysis revealed few nutritional deficiencies: two women with insufficient vitamin D status and one with insufficient folic acid status.

CONCLUSION

The women with celiac disease had an unbalanced diet with a higher intake of total- and saturated fatty acids and a lower intake of fiber compared to the general population. These findings emphasizes the need for nutritional follow-up of celiac patients and development of nutrient dense gluten-free products.

The Risk of Trigeminal Neuralgia Following Osteoporosis

Background and objectives: Managing people with trigeminal neuralgia (TN) and osteoporosis is challenging due to their debilitating conditions. Currently, the exact association between TN and osteoporosis in patients remains unknown, although there is potential overlapping of pathophysiological mechanisms. In response, we calculated TN risk in patients who have osteoporosis. Materials and Methods: 45,393 patients aged over 50 years diagnosed with osteoporosis were matched with 45,393 non-osteoporosis patients aged over 50 years (1:1 ratio) who were used as the control group, using data from 1996 to 2010 from Taiwan’s National Health Insurance Research Database. The cumulative incidences of subsequent TN and the hazard ratio were estimated using Cox proportional hazards modeling and the Kaplan–Meier method, respectively. Results: Among the total sample, 333 patients were diagnosed with TN during the follow-up period: 205 in the osteoporosis cohort and 128 in the control cohort. Through covariate adjustment, the overall TN incidence showed a 1.80-fold increase in the osteoporosis cohort in comparison with the control cohort (0.60 vs. 0.18 per 1000 person-years, respectively). The High Charlson Comorbidity Index, hypertension, and migraines were risk factors of TN. Conclusions: Osteoporosis patients had a higher TN risk than that of the control cohort. Therefore, early recognition of pain and symptoms in osteoporotic people may help to identify possible TN patients who need prompt therapy.

Osteoporosis and periodontal diseases - An update on their association and mechanistic links

Periodontitis and osteoporosis are prevalent inflammation-associated skeletal disorders that pose significant public health challenges to our aging population. Both periodontitis and osteoporosis are bone disorders closely associated with inflammation and aging. There has been consistent intrigue on whether a systemic skeletal disease such as osteoporosis will amplify the alveolar bone loss in periodontitis. A survey of the literature published in the past 25 years indicates that systemic low bone mineral density (BMD) is associated with alveolar bone loss, while recent evidence also suggests a correlation between clinical attachment loss and other parameters of periodontitis. Inflammation and its influence on bone remodeling play critical roles in the pathogenesis of both osteoporosis and periodontitis and could serve as the central mechanistic link between these disorders. Enhanced cytokine production and elevated inflammatory response exacerbate osteoclastic bone resorption while inhibiting osteoblastic bone formation, resulting in a net bone loss. With aging, accumulation of oxidative stress and cellular senescence drive the progression of osteoporosis and exacerbation of periodontitis. Vitamin D deficiency and smoking are shared risk factors and may mediate the connection between osteoporosis and periodontitis, through increasing oxidative stress and impairing host response to inflammation. With the connection between systemic and localized bone loss in mind, routine dental exams and intraoral radiographs may serve as a low-cost screening tool for low systemic BMD and increased fracture risk. Conversely, patients with fracture risk beyond the intervention threshold are at greater risk for developing severe periodontitis and undergo tooth loss. Various Food and Drug Administration-approved therapies for osteoporosis have shown promising results for treating periodontitis. Understanding the molecular mechanisms underlying their connection sheds light on potential therapeutic strategies that may facilitate co-management of systemic and localized bone loss.

Vitamin D, respiratory infections, and chronic disease: Review of meta-analyses and randomized clinical trials

BACKGROUND

Observational studies have suggested associations of vitamin D deficiency (VDD) with respiratory tract infections, impaired bone health, and myriad chronic diseases.

OBJECTIVE

To assess potential causal relationships between vitamin D supplementation and a reduced risk of these conditions, a review of the evidence across available meta-analyses of randomized control trials (RCTs) and RCTs was performed.

METHOD

PubMed, Embase, Cochrane Library, and Web of Science were searched from their inception to March 2021. We included only RCTs and meta-analyses of RCTs focusing on the association between vitamin D and respiratory disease, bone health, cardiovascular disease (CVD), diabetes mellitus, and cancer.

RESULTS

A total of 107 RCTs and 62 meta-analysis of RCTs were included. Although most RCTs did not support benefits of vitamin D supplementation, suggestive evidence for benefit was found in populations at greater risk of VDD and for acute respiratory infections, fractures in institutionalized older adults, type 2 diabetes among patients with prediabetes, and cancer mortality. In contrast, no compelling evidence for benefit was found for other respiratory conditions, fractures in community-dwelling adults, falls, cancer incidence, or CVD.

CONCLUSIONS

Current evidence from RCTs and meta-analyses of RCTs is inconsistent regarding the effects of vitamin D supplementation on respiratory infections and chronic diseases. Individuals most likely to benefit are those with baseline VDD or with selected high-risk conditions. Public health initiatives are needed to eliminate VDD globally, and future research will be enhanced by a 'precision prevention' approach to identify those most likely to benefit from vitamin D supplementation.

Low vitamin D levels and the long-term functional outcome of stroke up to 5 years

BACKGROUND AND PURPOSE

Previous studies have established that vitamin D was associated with stroke. The purpose of this study was to investigate the relationship between vitamin D and 5-year outcome of patients with stroke including acute ischemic stroke (AIS) and intracranial hemorrhage (ICH) stroke.

METHODS

Serum 25-hydroxyvitamin D levels were prospectively analyzed in patients admitted to the First Affiliated Hospital of Wenzhou Medical University from 2013 to 2015. Modified Rankin scale (mRS) was used to evaluate their 5-year functional outcome, and univariate and multivariate logistic regressions were applied to evaluate the effects of vitamin D on stroke outcome.

RESULTS

In total, 668 patients diagnosed with stroke were recruited, and 420 completed the 5-year follow-up. Ninety-five patients experienced poor outcome in the 5 years since stroke onset. Vitamin D levels in patients with poor outcome showed significant differences compared to good outcome patients (p < .001). In multivariable logistic regression analysis, after adjusting the potential confounders, the 5-year functional outcome was significantly associated with vitamin D levels. Stroke patients with vitamin D levels less than 38.4 nmol/L had a higher risk for poor outcome compared with those with vitamin D level over 71.4 nmol/L at 5-year (odds ratio [OR] = 3.66, 95% confidence interval [CI] = 1.42-9.45, p = .007), which was consistent with AIS patients (OR = 6.36, 95% CI = 1.89-21.44, p = .003).

CONCLUSION

Vitamin D level less than 38.4 nmol/L at admission is a potential risk biomarker for poor functional outcome at 5-year prognosis in AIS patients, which might provide new ideas for the prognostic assessment of stroke.

"Vitamin D Deficiency Is More Common in Women with Autoimmune Thyroiditis: A Retrospective Study"

BACKGROUND

Vitamin D is a hormone that is mainly produced in the skin upon ultraviolet B radiation exposure and has important influence on various organs. In recent years, data have been collected that vitamin D deficiency plays an important role in the development of various nonskeletal diseases, including autoimmune diseases. Chronic autoimmune thyroiditis (Hashimoto's thyroiditis) is one of the most common organ-specific autoimmune endocrine diseases. It is characterized by increased level of antithyroid peroxidase and/or antithyroglobulin antibodies in blood, which often leads to thyroid dysfunction and structural changes of the gland. There is an opinion that vitamin D deficiency may be considered as an important risk factor for development of chronic autoimmune thyroiditis, but data of various small studies are controversial. Despite the fact that Georgia is a sunny country, vitamin D deficiency is a widespread problem here. Thyroid diseases, including the chronic autoimmune thyroiditis, are also very common in Georgia. The aim of our research was to compare the level of vitamin D between the patients with chronic autoimmune thyroiditis and the healthy subjects.

METHODS

This retrospective study enrolled subjects, who were 18-70 years old and visited the clinics "Cortex" and "National Institute of Endocrinology" in 2018 or in 2019 from mid-spring to mid-summer. Data of thyroid-stimulating hormone, free thyroxine, antithyroid peroxidase antibodies, antithyroglobulin antibodies, thyroid ultrasonography, and 25(OH) vitamin D were retrospectively analysed based on medical history. In total, data of 1295 patients were collected. The statistical processing of data was performed through the SPSS 20 program.

RESULTS

The negative association between thyroid-stimulating hormone, antithyroid peroxidase antibodies, antithyroglobulin antibodies, heterogeneous parenchyma of thyroid gland, and vitamin D was found in women. Statistically significant association was not detected in men.

CONCLUSIONS

Serum vitamin D is lower in women with autoimmune thyroiditis and primary hypothyroidism. Further studies are needed to evaluate the influence of vitamin D supplementation on thyroid autoantibody positivity or primary hypothyroidism.

Associations between vitamin D receptor gene polymorphisms and spinal degenerative disease: evidence from a meta-analysis based on 35 case-control studies

OBJECTIVE

Dozens of reports on the associations of vitamin D receptor (VDR) gene polymorphisms and susceptibility to spinal degenerative disease (SDD) were conducted with inconsistent findings. This study aimed to elucidate the associations through a meta-analysis approach.

METHODS

Databases of PubMed, EMBASE, Web of Science, CNKI, and Wanfang were searched until July 10, 2020. Study quality was evaluated by using Newcastle-Ottawa Scale (NOS). Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated to evaluate the associations under allelic model (1 vs. 2), homozygous model (11 vs. 22), heterozygous model (12 vs. 22), dominant model (11 + 12 vs. 22), and recessive model (11 vs. 12 + 22).

RESULTS

A total of 5021 cases and 5746 controls from 35 studies were eligible to this meta-analysis. According to NOS, the included studies were in excellent quality. In the overall population, the pooled data indicated that ApaI was associated with a reduced SDD susceptibility (AA vs. Aa + aa, OR = 0.83, 95%CI 0.71 - 0.96, P = 0.010). But the association was not observed in FokI, TaqI, and BsmI polymorphisms. Subgroup analysis suggested that TaqI polymorphism was correlated to an elevated SDD risk in Asians (TT + Tt vs. tt, OR = 2.55, 95%CI 1.90 - 3.44, P < 0.001).

CONCLUSION

The present study indicates that ApaI polymorphism may contribute to a reduced risk to SDD in the overall population, and TaqI polymorphism confers an elevated susceptibility to SDD in Asians. While, BsmI and FokI polymorphisms appear to have no significant association with SDD.

Novel CYP24A1 Mutation in a Young Male Patient with Nephrolithiasis: Case Report

BACKGROUND/AIMS

The CYP24A1 gene encodes the vitamin D 24-hydroxylase enzyme, which hydroxylates active forms of vitamin D into inactive forms. Biallelic mutations in the CYP24A1 gene can lead to elevated levels of active vitamin D metabolites and, consequently, to hypercalcemia, hypercalciuria, nephrocalcinosis, and nephrolithiasis; however, monoallelic mutations have been associated only with milder phenotypes. In the present manuscript, we report the case of a young male patient who presented hypercalcemia and nephrolithiasis, suppressed parathormone, and elevated 1,25 dihydroxy vitamin D levels.

METHODS

Biochemical analyses were performed on Cobas 8000, F. Hoffmann-La Roche AG, Basel, Switzerland. The proband was initially evaluated for occult malignancies by body imaging, serum electrophoresis, and tumor markers, which did not reveal any pathology. DNA samples of the proband and his sibling were then examined using Sanger sequencing.

RESULTS

Genetic analysis revealed 2 compound heterozygous CYP24A1 mutations (p.L148P and p.R223*). The novel nonsense CYP24A1 mutation, p.R223*, was also found heterozygously in other family members with a medical history of nephrolithiasis.

CONCLUSIONS

The identification of this gene mutation causing hypercalcemia, hypercalciuria, and renal stones allows the specific management of endogenous vitamin D production.

Vitamin D Receptor Signaling Regulates Craniofacial Cartilage Development in Zebrafish

Vitamin D plays essential roles in supporting the skeletal system. The active form of vitamin D functions through the vitamin D receptor (VDR). A hereditary vitamin-D-resistant rickets with facial dysmorphism has been reported, but the involvement of VDR signaling during early stages of craniofacial development remains to be elucidated. The present study investigated whether VDR signaling is implicated in zebrafish craniofacial cartilage development using a morpholino-based knockdown approach. Two paralogous VDR genes, vdra and vdrb, have been found in zebrafish embryos. Loss-of-vdra has no discernible effect on cartilage elements, whereas loss-of-vdrb causes reduction and malformation of craniofacial cartilages. Disrupting both vdra and vdrb leads to more severe defects or complete loss of cartilage. Notably, knockdown of vdrb results in elevated expression of follistatin a (fsta), a bone morphogenetic protein (BMP) antagonist, in the adjacent pharyngeal endoderm. Taken together, these findings strongly indicate that VDR signaling is required for early craniofacial cartilage development in zebrafish.

Crosssectional Assessment of Bone Mass Density in Adults with Hepatitis B Virus and Hepatitis C Virus Infection

Osteoporosis is one of the major complications in chronic hepatitis B virus (HBV) and hepatitis C (HCV) infection. However, few studies had examined the relationship between hepatic viral infection with bone loss. Our aim was to investigate the association between hepatic viral infection with bone mineral density (BMD) in a cross-sectional study. Participants who attended the health examinations at the Tri-Service General Hospital (TSGH), Taiwan, were enrolled in the study. Diagnosis of viral hepatitis was confirmed by the serum viral markers of hepatitis B surface antigen (HBsAg) and anti-HCV, and BMD measurement was performed by the bone densitometry. Subjects were divided into four groups by the presence of viral markers. The association between hepatic viral infection and BMD was examined by a multivariate linear regression model. HBV infection was inversely associated with BMD after full adjusting with β values of -0.17 (95% CI: -0.29, -0.05) (p < 0.05). The relationship remained significant in males (β = -0.16, 95% CI = -0.31, -0.01) (p < 0.05). In subjects with body mass index less than 30 HBV infection was associated with reduced BMD (β = -0.16, 95% CI = -0.29, -0.02) (p < 0.05). However, HCV infection was only associated with an increase in BMD in patients with BMI less than 30 (β = 0.17, 95% CI = 0.21, 0.32) (p < 0.05). Chronic HBV infection was significantly associated with reduced BMD in males. The impact of viral hepatitis on bone health deserves further investigation for the potential pathophysiological mechanisms.

Bone mineral density and its correlation with vitamin D status in healthy school-going children of Western India

Studies on vitamin D deficiency status and its impact on bone health in a developing country are limited. We assessed the bone mineral density and vitamin D levels in healthy school-going children of Western India. Around 65% children had vitamin D deficiency and vitamin D levels had good correlation with bone mineral density.

PURPOSE

Vitamin D is an important substrate in the metabolism of calcium homeostasis and skeletal metabolism. Epidemiological studies on vitamin D deficiency status and its impact on bone mineral metabolism in healthy children in a developing country are limited. We assessed the bone mineral density and vitamin D levels in healthy school-going children of Western India.

METHODS

We measured serum levels of 25-hydroxy vitamin D (25(OH)D) in healthy school-going children, aged 60 to 120 months. Dual-energy X-ray absorptiometry scan was done to assess the bone mineral density (BMD). The BMD status was compared with the levels of 25(OH)D and serum parathormone hormone in all the children.

RESULTS

A total of 100 school-going children were examined for evidence of vitamin D deficiency and 65% had deficiency (less than 50 nmol/L). The mean age was 90 months in males and 89 months in females. In the vitamin D-deficient group, the mean BMD (gm/cm²) measurements for the lumbar spine was 0.439 ± 0.098 (p < 0.001) and the mean BMD (gm/cm²) in the normal group was 0.606 ± 0.071 (p < 0.001). Pearson's and Spearman's rank correlation coefficients between vitamin D levels and BMD z score showed a significant positive correlation (r = 0.82, ρ = 0.924).

CONCLUSIONS

We confirmed the high prevalence of vitamin D deficiency among healthy school-going children. The serum levels of vitamin 25(OH)D has a good correlation with bone mineral density.

The Effect of Clothing on Vitamin D Status, Bone Turnover Markers, and Bone Mineral Density in Young Kuwaiti Females

Many Arab women in the Gulf region cover their bodies for cultural and religious reasons, limiting the skin's exposure to sunlight and therefore its ability to synthesize vitamin D. The aim of this study is to determine whether the clothing style of Kuwaiti premenopausal women affects their vitamin D status, bone marker expression, and bone density. Three groups of healthy unmarried single Kuwaiti females (20-35 years old; n=30 per group) were recruited randomly from the general community: a control group who wear Western-style clothing (unveiled group), a group who wear a hejab that covers the whole body except for the face and hands (hejab group), and a group who wear a black veil with the entire body covered (veiled group). Bone mineral density (BMD), bone markers (procollagen type 1 N-terminal propeptide [P1NP], osteocalcin, and β-CrossLaps), 25-hydroxy vitamin D, intact parathyroid hormone [iPTH], and calcitonin were measured. The bone marker osteocalcin was significantly higher in the hejab group compared to the control group, whereas P1NP and β-CrossLaps were significantly higher in the veiled group compared to the control group. 25-hydroxy vitamin D, iPTH, calcitonin, and BMD were not significantly different across the three groups despite the observed elevation in bone turnover markers. The majority of participants in all three groups exhibited vitamin D deficiency; however, the lowest vitamin D levels were observed among the hejab and veiled participants. These findings suggest that clothing style may contribute to vitamin D deficiency in young Kuwaiti women.

Influence of lifestyle characteristics and VDR polymorphisms as risk factors for intervertebral disc degeneration: a case-control study

BACKGROUND

Intervertebral disc degeneration (DD) is an important cause of low back pain and its precise aetiology is not fully understood, being attributed to cumulative environmental, biomechanical and genetic effects. The vitamin D plays a key role in regulation of calcium homeostasis and bone mineralization, exerting its biological activities by binding to a high-affinity receptor (VDR). Polymorphisms in VDR gene were previously associated with DD process, however with conflicting results. Here, we aimed to investigate the influence of lifestyle characteristics and VDR TaqI, BsmI, ApaI and FokI polymorphisms as risk factors for DD process.

METHODS

Retrospective case-control study involving 231 participants: 119 with confirmed DD and 112 healthy controls. Genotyping of VDR polymorphisms was performed by PCR-RFLP and real-time PCR using TaqMan methodology. All patients answered a questionnaire regarding lifestyle characteristics, such as educational level, pain localization, smoking habits, engagement of physical activity, postural and load weight at work and familial history of disc degeneration. The variables were compared between groups and adjusted by age and gender.

RESULTS

The case group was composed by 52% female and 48% male and the mean age was 40.0 years old, while in the control group 79% was female and 21% male and the mean age was 32.0 years old. Although gender distribution and mean age were different between groups, in the control group all participants were less than 45 years old and there was a prevalence of women in both groups. The factors that could be possibly associated to DD in the Brazilian population studied included smoking habits (26% in cases and 9% in controls, p = 0.003), lack of engagement in physical activity (observed in 77% of cases and 62% of controls, p = 0.018), and loading weight during work routine (58% in cases and 24% in controls, p ≤ 0.001). However, after adjusting by age and gender, only smoking habits remained associated to disc degeneration (p = 0.027). Considering the educational level, 35.2% of cases and 15.6% of controls had only the Elementary School, and 5.5% of DD group and 28.6% of control group had completed College (p = 0.025). In addition, educational level was directly associated to load weight at work (p = 0.012). Regarding VDR polymorphisms, no significant difference in genotype and allele frequencies between groups was observed. The haplotype analysis revealed that the combined wild-type alleles of TaqI, ApaI and FokI polymorphisms-TGT-was observed in a higher frequency in control group (p = 0.039).

CONCLUSION

The findings suggested that smoking habits was a risk factor for disc degeneration in the population studied. Single analysis revealed no significant effects of VDR polymorphisms in disc degeneration process, while the combination of wild-type alleles of TaqI, ApaI and FokI polymorphisms, TGT haplotype, decreased the risk of the disease.

The effect of a single early high-dose vitamin D supplement on fracture union in patients with hypovitaminosis D: a prospective randomised trial

AIMS

To evaluate the effect of a single early high-dose vitamin D supplement on fracture union in patients with hypovitaminosis D and a long bone fracture.

PATIENTS AND METHODS

Between July 2011 and August 2013, 113 adults with a long bone fracture were enrolled in a prospective randomised double-blind placebo-controlled trial. Their serum vitamin D levels were measured and a total of 100 patients were found to be vitamin D deficient (< 20 ng/ml) or insufficient (< 30 ng/mL). These were then randomised to receive a single dose of vitamin D₃ orally (100 000 IU) within two weeks of injury (treatment group, n = 50) or a placebo (control group, n = 50). We recorded patient demographics, fracture location and treatment, vitamin D level, time to fracture union and complications, including vitamin D toxicity. Outcomes included union, nonunion or complication requiring an early, unplanned secondary procedure. Patients without an outcome at 15 months and no scheduled follow-up were considered lost to follow-up. The t-test and cross tabulations verified the adequacy of randomisation. An intention-to-treat analysis was carried out.

RESULTS

In all, 100 (89%) patients had hypovitaminosis D. Both treatment and control groups had similar demographics and injury characteristics. The initial median vitamin D levels were 16 ng/mL (interquartile range 5 to 28) in both groups (p = 0.885). A total of 14 patients were lost to follow-up (seven from each group), two had fixation failure (one in each group) and one control group patient developed an infection. Overall, the nonunion rate was 4% (two per group). No patient showed signs of clinical toxicity from their supplement.

CONCLUSIONS

Despite finding a high level of hypovitaminosis D, the rate of union was high and independent of supplementation with vitamin D₃. Cite this article: Bone Joint J 2017;99-B:1520-5.

Association between the vitamin D receptor gene polymorphism and osteoporosis

The influence of the vitamin D receptor (VDR) gene for the risk of osteoporosis remains to be elucidated. The aim of the present study was to understand the distribution of various single-nucleotide polymorphisms (SNPs) within the VDR gene and its association with the risk of osteoporosis. In total, 378 subjects without a genetic relationship were recruited to the study between January 2013 and July 2015. The subjects were divided into three groups, which were the normal (n=234), osteoporosis (n=65) and osteoporosis with osteoporotic fracture (n=79) groups. Three pertinent SNPs of the VDR gene rs17879735 (ApaI, Allele A/a, SNP C>A) were examined with polymerase chain reaction-restriction fragment length polymorphism. The bone mineral density (BMD) of the lumbar spine (L2-L4), femoral neck, Ward's and Tro was measured using dual-energy X-ray absorptiometry. The distributions of genotype frequencies aa, AA and Aa were 48.68, 42.86 and 8.46%, separately. Following analysis of each site, BMD, body mass index (BMI) and age, BMD for each site was negatively correlated with age (P<0.01) and positively correlated with BMI (P<0.01). Correction analysis revealed that there were significant differences in the Ward's triangle BMD among each genotype (P<0.05), in which the aa genotype exhibited the lower BMD (P<0.05). No significant difference was identified among the different genotypes in the occurrence of osteoporosis with osteoporotic fracture (P>0.05). In conclusion, these indicated that the VDR gene ApaI polymorphisms had an important role in the osteoporosis risk.

Attenuation of hind-limb suspension-induced bone loss by curcumin is associated with reduced oxidative stress and increased vitamin D receptor expression

Treatment with curcumin attenuated modeled microgravity-induced bone loss, possibly through abating oxidative stress and activating vitamin D receptor. Curcumin might be an effective countermeasure for microgravity-induced bone loss but remains to be tested in humans.

INTRODUCTION

Bone loss is one of the most important complications for human crewmembers who are exposed to long-term microgravity in space and also for bedridden people. The aim of the current study was to elucidate whether treatment with curcumin attenuated bone loss induced by microgravity.

METHODS

We used hind-limb suspension (HLS) and rotary wall vessel bioreactor (RWVB) to model microgravity in vivo and in vitro, respectively. We investigated the effects of curcumin consumption (40 mg kg(-1) body weight day(-1), via daily oral gavages) on Sprague-Dawley (SD) rats exposed to HLS for 6 weeks. Then, we investigated the effects of incubation with curcumin (4 μM) on MC3T3-E1 and RAW264.7 cells cultured in RWVB.

RESULTS

Curcumin alleviated HLS-induced reduction of bone mineral density in tibiae and preserved bone structure in tibiae and mechanical strength in femurs. Curcumin alleviated HLS-induced oxidative stress marked by reduced malondialdehyde content and increased total sulfhydryl content in femurs. In cultured MC3T3-E1 cells, curcumin inhibited modeled microgravity-induced reactive oxygen species (ROS) formation and enhanced osteoblastic differentiation. In cultured RAW264.7 cells, curcumin reduced modeled microgravity-induced ROS formation and attenuated osteoclastogenesis. In addition, curcumin upregulated vitamin D receptor (VDR) expression in femurs of rats exposed to HLS and MC3T3-E1 cells exposed to modeled microgravity.

CONCLUSION

Curcumin alleviated HLS-induced bone loss in rats, possibly via suppressing oxidative stress and upregulating VDR expression.

Association of Vitamin D With Stress Fractures: A Retrospective Cohort Study

Vitamin D is an essential, fat-soluble nutrient that is a key modulator of bone health. Despite the gaining popularity throughout published medical studies, no consensus has been reached regarding a serum vitamin D level that will guarantee adequate skeletal health in a patient with an increased functional demand. The purpose of the present investigation was to examine the serum concentrations of vitamin D in patients with confirmed stress fractures. A total of 124 patients were included in our retrospective cohort study. Of the 124 patients, 53 had vitamin D levels measured within 3 months of diagnosis. An association was seen in patients with a stress fracture and vitamin D level measured, as 44 (83.02%) of the 53 patients had a serum 25-hydroxyvitamin D level <40 ng/mL. Although an association was seen at our institution in patients with stress fractures and a serum vitamin D concentration <40 ng/mL, a larger and prospective investigation is warranted to further understand the effect of vitamin D level and stress fracture prevention in an active, nonmilitary population.

Analysis of Body Composition and Food Habits of Spanish Celiac Women

The purpose of the present work was both to analyze composition of Spanish celiac women and to study the food habits and gluten-free diet of these celiac patients, in order to determine whether they achieve a balanced and healthy diet as well as to highlight nutritional qualitative and/or quantitative differences. 54 adult celiac women (34 ± 13 years) took part in the six-month study. Height, weight and body composition were measured. An analysis of energy consumption and of the macronutrient distribution of their diet was carried out. Their fulfillment of micronutrient intake recommendations was verified. Participants showed a Body Mass Index of 21.6 ± 2.4 kg/m2. Energy Intake was slightly lower than the Dietary Reference Intakes. Excessive protein apart from over-consumption of fat was observed. More than three quarters of participants consumed meat in excess. Carbohydrate consumption along with that of fiber was below recommended levels. Vitamin D, iron, and iodine had a low percentage of recommendation compliance. In general, participants followed the recommendations of dairy products and fruit intake whereas vegetable consumption was not enough for the vast majority. We conclude that although the diet of celiac women does not differ much from the diet of general population, some considerations, such as reducing fat and protein consumption and increasing fiber intake, must be taken into account.

The effects of 1α, 25-dihydroxyvitamin D3 and transforming growth factor-β3 on bone development in an ex vivo organotypic culture system of embryonic chick femora

Transforming growth factor-beta3 (TGF-β3) and 1α,25-dihydroxyvitamin D₃ (1α,25 (OH) ₂D₃) are essential factors in chondrogenesis and osteogenesis respectively. These factors also play a fundamental role in the developmental processes and the maintenance of skeletal integrity, but their respective direct effects on these processes are not fully understood. Using an organotypic bone rudiment culture system the current study has examined the direct roles the osteotropic factors 1α,25 (OH)₂D₃ and TGF-β3 exert on the development and modulation of the three dimensional structure of the embryonic femur. Isolated embryonic chick femurs (E11) were organotypically cultured for 10 days in basal media, or basal media supplemented with either 1α,25 (OH) ₂D₃ (25 nM) or TGF-β3 (5 ng/mL & 15 ng/mL). Analyses of the femurs were undertaken using micro-computed tomography (μCT), histology and immunohistochemistry. 1α,25 (OH)2D3 supplemented cultures enhanced osteogenesis directly in the developing femurs with elevated levels of osteogenic markers such as type 1 collagen. In marked contrast organotypic femur cultures supplemented with TGF-β3 (5 ng/mL & 15 ng/mL) demonstrated enhanced chondrogenesis with a reduction in osteogenesis. These studies demonstrate the efficacy of the ex vivo organotypic embryonic femur culture employed to elucidate the direct roles of these molecules, 1α,25 (OH) ₂D₃ and TGF-β3 on the structural development of embryonic bone within a three dimensional framework. We conclude that 1α,25(OH)₂D and TGF-β3 modify directly the various cell populations in bone rudiment organotypic cultures effecting tissue metabolism resulting in significant changes in embryonic bone growth and modulation. Understanding the roles of osteotropic agents in the process of skeletal development is integral to developing new strategies for the recapitulation of bone tissue in later life.

Lower bone mineral density in Somali women living in Sweden compared with African-Americans

Vitamin D deficiency can lead to osteomalacia. Bone mineral density was lower in Somali women, living in Sweden, in relation to both the American and the African-American reference populations. The majority, 73 %, had vitamin D deficiency, and supplementation should be considered to prevent from osteomalacia, osteoporosis and future fractures.

PURPOSE

Low vitamin D can lead to osteomalacia. The hypothesis was that bone mineral density (BMD) in Somali women living in Sweden was lower in comparison with different ethnic reference populations.

METHODS

Women from Somalia, n = 67, median age 35.8 years (range 18 to 56), latitude 0-10° North living in Gothenburg, Sweden, latitude 57° North, >2 years were studied. All wore traditional Islamic clothing and had skin photo type V. BMD was recorded as the Z-score and compared with white American and African-American women, respectively, using standard data from the dual energy X-ray absorptiometry (DXA) manufacturer (Lunar Prodigy enCORETM, GE Healthcare, LU44663). A fasting blood test was drawn for analysis of serum 25(OH)D.

RESULTS

The median Z-score compared with the American white population was -0.9 SD of the lumbar spine (p < 0.00001), 0.1 SD of the left hip and 0.0 SD of the right hip (ns). The median Z-score compared with the African-American population was -1.6 SD of the lumbar spine (p < 0.00001), -0.9 SD of the left hip and -0.9 SD of the right hip (p < 0.001). The majority, 73 %, had vitamin D deficiency, serum 25(OH)D <25 nmol/l (<10 ng/ml). BMD did not correlate to vitamin D levels or to the number of years in Sweden. One wrist fracture was reported.

CONCLUSIONS

BMD was lower in these fairly young immigrant women from Somalia, living in Sweden, in relation to both the American and the African-American reference populations. Vitamin D supplementation should be considered to prevent from osteomalacia, osteoporosis and future fractures.

Osteoporosis and osteomalacia - clinical and diagnostic problems

Aim: to define main clinical and diagnostical problems related to osteoporosis and osteomalacia. Literature data showed that not only osteoporosis but osteomalacia may be the reason for decreasing of mechanical properties of skeleton with risk of low-energy fractures. The solution of associated medical and social problems is difficult because DEXA does not allow to differentiate between osteoporosis and osteomalacia that leads to misdiagnosis and unnecessary prescription of antiosteoporotic drugs. This approach is pathogenetically unproved and even may be harmful for the patient. Osteoporosis and osteomalacia does not exclude each other so bone mass reducing in one cohort of patient may be due to osteoporosis, other - osteomalacia and some of them - combinations of both. Another point is that results of controlled clinical trials that evaluated efficacy of antiosteoporotic drugs without differentiative histology tests for osteoporosis and osteomalacia are of doubtful value. As the bone biopsy that is necessary for osteomalacia diagnosis is invasive procedure there is need in definition of clear criteria when it has to be done in patient with reduced bone mass.

Effect of fat on serum 25-hydroxyvitamin D levels after a single oral dose of vitamin D in young healthy adults: a double-blind randomized placebo-controlled study

PURPOSE

This double-blind placebo-controlled trial evaluated serum 25-hydroxyvitamin D [25(OH)D] levels after the oral intake of a single dose of cholecalciferol during one of the three meals, containing different amounts of fat or placebo.

METHODS AND RESULTS

Sixty-four healthy medical residents or students of a university hospital in Porto Alegre, latitude 30° S, Brazil, were divided into four groups. Three groups received a single 50,000 IU oral dose of cholecalciferol during a meal containing 0 g (Group 1), 15 g (Group 2) or 30 g (Group 3) of fat, and one group received placebo (Group 4), according to randomization. Serum 25(OH)D, parathyroid hormone, total calcium, albumin, magnesium, and creatinine levels, and urinary calcium, magnesium, and creatinine levels were measured at baseline and after 14 days. Baseline mean serum 25(OH)D levels were low in all groups. Vitamin D given during breakfast increased the mean change of serum 25(OH)D levels, when compared to placebo. Furthermore, the intake of fat with vitamin D increased the mean change of serum 25(OH)D levels.

CONCLUSION

A single oral dose of vitamin D given with food increased mean serum 25(OH)D levels, after 2 weeks, and the mean increase was larger, when the meal had at least 15 g of fat. These findings can have important implications to oral vitamin D supplementation.

Choline kinase beta is required for normal endochondral bone formation

BACKGROUND

Choline kinase has three isoforms encoded by the genes Chka and Chkb. Inactivation of Chka in mice results in embryonic lethality, whereas Chkb(-/-) mice display neonatal forelimb bone deformations.

METHODS

To understand the mechanisms underlying the bone deformations, we compared the biology and biochemistry of bone formation from embryonic to young adult wild-type (WT) and Chkb(-/-) mice.

RESULTS

The deformations are specific to the radius and ulna during the late embryonic stage. The radius and ulna of Chkb(-/-) mice display expanded hypertrophic zones, unorganized proliferative columns in their growth plates, and delayed formation of primary ossification centers. The differentiation of chondrocytes of Chkb(-/-) mice was impaired, as was chondrocyte proliferation and expression of matrix metalloproteinases 9 and 13. In chondrocytes from Chkb(-/-) mice, phosphatidylcholine was slightly lower than in WT mice whereas the amount of phosphocholine was decreased by approximately 75%. In addition, the radius and ulna from Chkb(-/-) mice contained fewer osteoclasts along the cartilage/bone interface.

CONCLUSIONS

Chkb has a critical role in the normal embryogenic formation of the radius and ulna in mice.

GENERAL SIGNIFICANCE

Our data indicate that choline kinase beta plays an important role in endochondral bone formation by modulating growth plate physiology.

The role of midkine in skeletal remodelling

Bone tissue is subjected to continuous remodelling, replacing old or damaged bone throughout life. In bone remodelling, the coordinated activities of bone-forming osteoblasts and bone-resorbing osteoclasts ensure the maintenance of bone mass and strength. In early life, the balance of these cellular activities is tightly regulated by various factors, including systemic hormones, the mechanical environment and locally released growth factors. Age-related changes in the activity of these factors in bone remodelling can result in diseases with low bone mass, such as osteoporosis. Osteoporosis is a systemic and age-related skeletal disease characterized by low bone mass and structural degeneration of bone tissue, predisposing the patient to an increased fracture risk. The growth factor midkine (Mdk) plays a key role in bone remodelling and it is expressed during bone formation and fracture repair. Using a mouse deficient in Mdk, our group have identified this protein as a negative regulator of bone formation and mechanically induced bone remodelling. Thus, specific Mdk antagonists might represent a therapeutic option for diseases characterized by low bone mass, such as osteoporosis.

LINKED ARTICLES

This article is part of a themed section on Midkine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-4.

The relationship between serum 25-hydroxy vitamin D, parathormone and bone mineral density in Indian population

OBJECTIVES

Vitamin D deficiency (VDD) is a global problem. Not all patients with VDD have clinical manifestations or secondary hyperparathyroidism. We studied the interaction between serum 25-hydroxy vitamin D (25OHD), parathormone (PTH) and bone mineral density (BMD) in Indian adolescents and adults.

DESIGN

Population survey.

PATIENTS

A total of 1829 adolescents and 1346 adults aged 50 years and above were analysed in this study.

MEASUREMENTS

Serum biochemistry, 25OHD, PTH and BMD were estimated. Subjects were grouped according to quartiles of serum PTH. VDD was defined as severe (25OHD ≤ 5 ng/ml), moderate (25OHD ≤ 10 ng/ml) and mild (25OHD ≤ 20 ng/ml) and secondary hyperparathyroidism (SHPT) when serum PTH levels >65 pg/ml.

RESULTS

Only 30-40% of subjects with moderate and severe VDD, respectively, had SHPT. BMD decreased from Quartile 1 to Quartile 4 of PTH at all sites among adolescents and adults, with only a marginal decline in serum 25OHD levels between these quartiles. Further, within each PTH quartile, there was no difference in BMD according to categories of VDD. Analysing BMD in the different PTH quartiles, the PTH cut-offs beyond which BMD showed a significant decline, was 35 pg/ml in adolescents and 53 pg/ml in adults.

CONCLUSIONS

Less than half of the subjects with VDD have SHPT. BMD levels start to decline at PTH values currently considered to be normal. These data suggest the need to redefine SHPT in different age groups keeping in mind the relationship between PTH and BMD. This may also influence the decision to supplement subjects with VDD.

Hemodynamic correlates of low umbilical cord vitamin D and ionized calcium

Vitamin D deficiency and hypocalcemia are associated with gestational hypertension. Therefore, we hypothesized that umbilical cord [Ca(2+)] and [vitamin D] are correlated with perinatal blood pressures. Mothers and newborns comprised vitamin D sufficient (vitamin D ≥ 50 nM, range 52-111 nM, n = 14), and vitamin D deficient groups (vitamin D < 50 nM, range 13-49 nM, n = 29). Cord [Ca²⁺] was negatively correlated with maternal systolic pressure (SBP) (r = -0.56, p < 0.01) and positively correlated with neonatal SBP (r = +0.55, p < 0.01) in the vitamin D deficient group. We conclude that low umbilical cord [vitamin D] and [Ca²⁺] may predispose mothers to higher and newborns to lower blood pressures.

Vitamin D Measurements — Facts and Fancies

Clinical laboratories have seen an increased interest in vitamin D measurements as new knowledge about the vitamin's pathobiology escalates. Clinicians now recognise that besides bone health, vitamin D insufficiency may be associated with potential health risks such as coronary artery disease, diabetes, depression, epilepsy, polycystic ovaries, musculoskeletal pain, autoimmune disease, multiple sclerosis, and cancers. While vitamin D testing and supplementation has been touted for these patients, benefit is evident only for the prevention of falls and fractures. The main form of vitamin D measured is 25-hydroxy-vitamin D (25OHD). While 25OHD assays have improved, they remain a work in progress.

Vitamin D receptor (VDR) gene polymorphism influences the risk of osteoporosis in postmenopausal women of Northwest India

SUMMARY

The influence of VDR gene for the risk of osteoporosis has remained inconclusive. VDR gene polymorphism in relation to BMD in postmenopausal women of Northwest India revealed a susceptibility haplotype AGT. Possession of this haplotype exacerbates the risk of osteoporosis by 2.8 times, which manifests in recessive mode of inheritance.

PURPOSE

The purpose of this study is to understand the influence of coordinated effect of various single nucleotide polymorphisms (SNPs) within vitamin D receptor (VDR) gene for the risk of osteoporosis, which has remained undefined so far.

METHODS

Four pertinent SNPs of VDR gene, i.e., rs2228570, rs1544410, rs17879735, and rs731236 were examined with polymerase chain reaction-restriction fragment length polymorphism in dual energy X-ray absorptiometry verified 188 osteoporotics, 115 osteopenics, and 147 normal postmenopausal women of Northwest India.

RESULTS

Minor allele 'T' of rs2228570 showed significant influence for the risk of osteoporosis (OR 1.60, 95%CI 1.16-2.20, P=0.004) and also in dominant (OR 2.32, 95%CI 1.47-3.64, P=0.0006) and additive model (OR 2.41, 95%CI 1.49-3.87, P=0.0006) after Bonferroni correction. Minor allele (T) of rs2228570 showed an allele dose effect with BMD of L1-L4 (P=0.009) and FN (P=0.036). Disease association analysis exposed a susceptibility haplotype AGT which influences the risk of osteopenia (OR 2.04, 95%CI 1.03-4.08, P=0.036) and osteoporosis (OR 2.90, 95%CI 1.61-5.38, P=0.00005) after adjusting the effects of age, BMI and years since menopause. This haplotype is significantly associated with BMDs at lumbar spine (P=0.0001) and femoral neck (P=0.016).

CONCLUSION

In-depth analysis of this haplotype with other methods of Wald statistics and Akaike information criterion confirmed that carriers of each unit of this haplotype AGT increases the risk of osteoporosis by a factor of 2.80±0.34 (β±SE) which manifests (P=0.1 × 10⁻⁶) in its recessive mode of inheritance.

Vitamin D - effects on skeletal and extraskeletal health and the need for supplementation

Vitamin D, the sunshine vitamin, has received a lot of attention recently as a result of a meteoric rise in the number of publications showing that vitamin D plays a crucial role in a plethora of physiological functions and associating vitamin D deficiency with many acute and chronic illnesses including disorders of calcium metabolism, autoimmune diseases, some cancers, type 2 diabetes mellitus, cardiovascular disease and infectious diseases. Vitamin D deficiency is now recognized as a global pandemic. The major cause for vitamin D deficiency is the lack of appreciation that sun exposure has been and continues to be the major source of vitamin D for children and adults of all ages. Vitamin D plays a crucial role in the development and maintenance of a healthy skeleton throughout life. There remains some controversy regarding what blood level of 25-hydroxyvitamin D should be attained for both bone health and reducing risk for vitamin D deficiency associated acute and chronic diseases and how much vitamin D should be supplemented.