Racial differences in the relationship between vitamin D, bone mineral density, and parathyroid hormone in the National Health and Nutrition Examination Survey

Post Hoc Analysis of National Institute of Child Health and Human Development Vitamin-D Pregnancy Cohort and The Role of Functional Vitamin-D Deficiency in Pregnancy

OBJECTIVE

Our objective was to conduct a secondary, post hoc analysis of the National Institute of Child Health and Human Development (NICHD) vitamin D (vitD) pregnancy study by Hollis et al, which reported on the effect of vitD supplementation in pregnant women and determine the potential interaction between intact parathyroid hormone (iPTH) concentrations, vitD status, and various comorbidities associated with pregnancy. Women with low 25-hydroxy vitamin D (25(OH)D) concentrations and high iPTH concentrations during pregnancy, known as functional vitamin-D deficiency (FVDD), were more likely to acquire complications also affecting their neonates.

STUDY DESIGN

This post hoc analysis of data collected from a diverse group of pregnant women participating in the NICHD vitD pregnancy study was applied to investigate the applicability of the concept of FVDD in pregnancy (Hemmingway, 2018) in identifying potential risks for certain comorbidities of pregnancy. This analysis defines FVDD as maternal serum 25(OH)D concentrations below 20 ng/mL and iPTH concentrations above 65 pg/mL creating a definitive ratio number, 0.308, to classify mothers as having FVDD prior to delivery (PTD). Statistical analyses were performed using SAS 9.4 (Cary, NC).

RESULTS

In total, 281 women (85 African American, 115 Hispanic, and 81 Caucasian) with 25(OH)D and iPTH concentrations measured at monthly visits were included in this analysis. No statistically significant association was found between mothers classified as having FVDD at baseline or 1-month PTD and hypertensive disorders of pregnancy, infection, or admittance to the neonatal intensive care unit. When combining all comorbidities of pregnancy in this cohort, results showed those with FVDD at baseline, 24 weeks' gestation, and 1-month PTD were more likely to experience a comorbidity (p = 0.001; p = 0.001; p = 0.004, respectively). Those with FVDD 1-month PTD were 7.1 times (confidence interval [CI]: 1.71-29.81) more likely to have preterm birth (<37 weeks) than women without FVDD.

CONCLUSION

Participants were more likely to have experienced preterm birth if they met the criteria for FVDD. This study supports the importance of FVDD during pregnancy.

KEY POINTS

· Functional vitamin D deficiency (FVDD) is defined as the ratio of 25(OH)D divided by iPTH concentration ≤0.308.. · At a minimum, it is recommended that vitamin D status be kept in the healthy range based on current recommendations for pregnant individuals.. · FVDD is a more sensitive predictor of pregnancy risk than 25(OH)D alone.. · FVDD identified those with greater risk of preterm birth in this cohort..

A review of dairy food intake for improving health among black children and adolescents in the US

Adequate nutrition during childhood and adolescence is crucial for proper neurological, musculoskeletal, immunological, and cardiometabolic health and development. Yet, disparities among socially underserved racial/ethnic groups in the United States (US) provide significant challenges to achieving adequate nutrition during these years of rapid growth and maturation. For example, Black children and adolescents are at greater risk for having food insecurity, lower-quality diets, obesity, and numerous associated health challenges that result from these disparities compared to their White peers. A growing body of evidence indicates that improving diet quality is critical for improving childhood and adolescent health and well-being, and that the diverse nutritional profile and bioactive compounds found within dairy foods may play multiple roles in promoting proper growth and development during these life stages. Therefore, to support overall health and development among Black youth, greater education and implementation efforts are needed to help this population meet the national dietary recommendations of 2.5 to 3 servings of dairy foods per day. Continuing to fall short of these recommendations puts Black children and adolescents at risk of multiple nutrient inadequacies and health disparities that can have lifelong impacts on disease development, mental health, and quality of life. This review presents the state of knowledge on health disparities and modifiable nutritional strategies involving milk and dairy foods to support the growth and maturation of children and adolescents, with a special focus on Black youth in the US.

Development and Validation of a Nomogram Model for Individualizing the Risk of Osteopenia in Abdominal Obesity

OBJECTIVE

This study was aimed to create and validate a risk prediction model for the incidence of osteopenia in individuals with abdominal obesity.

METHODS

Survey data from the National Health and Nutrition Examination Survey (NHANES) database for the years 2013-2014 and 2017-2018 was selected and included those with waist circumferences ≥102 m in men and ≥88 cm in women, which were defined as abdominal obesity. A multifactor logistic regression model was constructed using LASSO regression analysis to identify the best predictor variables, followed by the creation of a nomogram model. The model was then verified and evaluated using the consistency index (C-index), area under the receiver operating characteristic (ROC) curve (AUC), calibration curve, and decision curve analysis (DCA). Results Screening based on LASSO regression analysis revealed that sex, age, race, body mass index (BMI), alkaline phosphatase (ALP) and Triglycerides (TG) were significant predictors of osteopenia development in individuals with abdominal obesity (P < 0.05). These six variables were included in the nomogram. In the training and validation sets, the C indices were 0.714 (95 % CI: 0.689-0.738) and 0.701 (95 % CI: 0.662-0.739), respectively, with corresponding AUCs of 0.714 and 0.701. The nomogram model exhibited good consistency with actual observations, as demonstrated by the calibration curve. The DCA nomogram showed that early intervention for at-risk populations has a net positive impact.

CONCLUSION

Sex, age, race, BMI, ALP and TG are predictive factors for osteopenia in individuals with abdominal obesity. The constructed nomogram model can be utilized to predict the clinical risk of osteopenia in the population with abdominal obesity.

25 [OH] Vitamin D and Intact Parathyroid Hormone in Congolese Hemodialysis Patients: Evaluation of KDIGO Targets

Background

Data on 25 [OH] vitamin D and intact parathyroid hormone [iPTH] in hemodialysis patients are very limited in sub-Saharan African countries. The present study aimed to assess the magnitude of hypovitaminosis D, and to evaluate the achievement of iPTH KDIGO 2017 targets among chronic hemodialysis patients followed in Kinshasa.

Methods

We conducted a multicenter cross-sectional study in 6 hospitals in Kinshasa. All patients followed on hemodialysis for more than 3 months were included. Hypovitaminosis D was defined as <30 ng/mL (insufficiency = 20-29 ng/mL; deficiency if <20 ng/mL) and the targets for iPTH values were based on the 2017 KDIGO guidelines. The determinants for hypovitaminosis D were evaluated by logistic regression.

Results

251 patients [mean age 56 ± 14 years, 72.5% men, 63% hypertensive, 31% diabetic, 100% supplemented with native 25 [OH] vitamin D + CaCO3 were included. Hypovitaminosis D was found in 79.7% (deficiency 47.4%) and was associated with the male gender aOR 2.7 [1.4-5.2], p = 0.004, the low-permeability dialyzer 2.2 [1.1-4.2], p = 0.025 and anemia 3.9 [1.2-12.7], p = 0.022. Only 40% of patients with 25 [OH] vitamin D deficiency had iPTH according to KDIGO targets vs 6% of patients with severe hyperparathyroidism (iPTH > 600 pg/mL), 45% with levels between 16 and 150 pg/mL and 9% a iPTH ≤ 15 pg/mL.

Conclusion

Despite a sunny environment, a large proportion of Congolese hemodialysis patients have hypovitaminosis D, in particular a deficiency. Among them, less than half have target iPTH values. These results show the benefit of regular monitoring of these parameters in order to optimize treatment.

Vitamin D/Bone Mineral Density and Triglyceride Paradoxes Seen in African Americans: A Cross-Sectional Study and Review of the Literature

Vitamin D is known to have a positive effect on bone health. Despite the greater frequency of vitamin D deficiency in African Americans (AA), they have a higher bone mineral density (BMD) compared to whites, demonstrating a disconnect between BMD and vitamin D levels in AA. Another intriguing relationship seen in AA is the triglyceride (TG) paradox, an unusual phenomenon in which a normal TG status is observed even when patients house conditions known to be characterized by high TG levels, such as Type II diabetes. To the best of our knowledge, no study has examined whether these two paradoxical relationships exist simultaneously in AA subjects with Type II diabetes. In this study, we compared levels of blood markers, including HbA1c, TG, and vitamin D, measured as serum 25-hydroxyvitamin D [25(OH)VD] µM/mL, [25(OH)VD]/TG, calcium, and BMD in AA (n = 56) and white (n = 26) subjects with Type II diabetes to see whether these relationships exist concurrently. We found that AA subjects had significantly lower TG and [25(OH)VD] levels and a significantly higher BMD status compared to white subjects, even when the ages, BMI, duration of diabetes, HbA1c, and calcium levels were similar between the two groups. This demonstrates that these two paradoxical relationships exist simultaneously in Type II diabetic AA subjects. In addition to these findings, we discuss the current hypotheses in the literature that attempt to explain why these two intriguing relationships exist. This review also discusses four novel hypotheses, such as altered circulating levels and the potential role of estrogen and hydrogen sulfide on BMD and HMG-CoA reductase as a possible contributor to the TG paradox in AA subjects. This manuscript demonstrates that there are still many unanswered questions regarding these two paradoxical relationships and further research is needed to determine why they exist and how they can be implemented to improve healthcare.

The Obesity Paradox in Thyroid Surgery: Is Higher BMI Protective Against Hypoparathyroidism?

BACKGROUND

With a demonstrated association between adiposity and parathyroid hormone (PTH) levels, we hypothesized that patients with a higher body mass index (BMI) would have lower rates of postoperative hypoparathyroidism following total thyroidectomy.

METHODS

retrospective review of patients undergoing total thyroidectomy from 2015 to 2021. Demographics, BMI, surgical indications, and laboratory data including pre- and postoperative PTH values were examined.

RESULTS

Of the 352 patients with complete clinicopathologic data, most were female (n = 272, 77.3%) with an average age of 42.7 (SD+/-19.4). Obese (BMI 30-39.99) was most common BMI group (n = 108, 30.8%), with 11.7% (n = 41) morbidly obese (BMI > 40). Morbidly obese patients had significantly higher postoperative PTH levels than BMI < 18.5 (46.0 vs 19.3 pg/mL, P = .004). Patient race was significantly associated with pre- and postoperative PTH (P = .03, P = .004.) On multivariable analysis, preoperative PTH, race, and BMI were independent predictors of higher postoperative PTH (P < .05 for all).

DISCUSSION

Patients with higher BMI and non-white race have relative protection from postoperative hypoparathyroidism.

Interrogating Causal Effects of Body Composition and Puberty-Related Risk Factors on Adolescent Idiopathic Scoliosis: A Two-Sample Mendelian Randomization Study

Adolescent idiopathic scoliosis (AIS) is the most common form of pediatric musculoskeletal disorder. Observational studies have pointed to several risk factors for AIS, but almost no evidence exists to support their causal association with AIS. Here, we applied Mendelian randomization (MR), known to limit bias from confounding and reverse causation, to investigate causal associations between body composition and puberty-related exposures and AIS risk in Europeans and Asians. For our two-sample MR studies, we used single nucleotide polymorphisms (SNPs) associated with body mass index (BMI), waist-hip ratio, lean mass, childhood obesity, bone mineral density (BMD), 25-hydroxyvitamin D (25OHD), age at menarche, and pubertal growth in large European genome-wide association studies (GWAS), and with adult osteoporosis risk and age of menarche in Biobank Japan. We extracted estimates of the aforementioned SNPs on AIS risk from the European or Asian subsets of the largest multiancestry AIS GWAS (N = 7956 cases/88,459 controls). The results of our inverse variance-weighted (IVW) MR estimates suggest no causal association between the aforementioned risk factors and risk of AIS. Pleiotropy-sensitive MR methods yielded similar results. However, restricting our analysis to European females with AIS, we observed a causal association between estimated BMD and the risk of AIS (IVW odds ratio for AIS = 0.1, 95% confidence interval 0.01 to 0.7, p = 0.02 per SD increase in estimated BMD), but this association was no longer significant after adjusting for BMI, body fat mass, and 25OHD and remained significant after adjusting for age at menarche in multivariable MR. In conclusion, we demonstrated a protective causal effect of BMD on AIS risk in females of European ancestry, but this effect was modified by BMI, body fat mass, and 25OHD levels. Future MR studies using larger AIS GWAS are needed to investigate small effects of the aforementioned exposures on AIS. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Vitamin D Status in Children With High-risk Neuroblastoma

BACKGROUND

Vitamin D deficiency has become a matter of concern in pediatric cancer patients. A relationship between neuroblastoma and Vitamin D signaling pathways has been revealed with interest in the antiproliferative and antiinvasive properties of vitamin D. Our aim is to describe the prevalence of Vitamin D deficiency among children with high-risk neuroblastoma (HR-NB) and to explore its association with disease status.

MATERIALS AND METHODS

In all, 182 patients with HR-NB were managed at our center from 2017 to 2021. Serum 25(OH)D levels were tested at the first blood analysis performed and correlated with clinical data and disease status.

RESULTS

One hundred forty-eight (81.4%) had low 25(OH)D levels (48.4% categorized as deficiency (25(OH)D below 20 ng/mL) and 33.0% as insufficiency (25(OH)D 20 to 30 ng/mL). Median Vitamin D level was 20.2 ng/mL. Vitamin D levels were not associated with race or sex. Although malnourished patients had lower median 25(OH)D levels(11.1 ng/mL), no statistical association was observed with Vitamin D deficiency. There was no association between Vitamin D levels and disease status. An inverse correlation was found between age and vitamin D levels ( P =0.0040).

CONCLUSION

A concerning high prevalence of low Vitamin D levels affects more than two-thirds of patients with HR-NB in our cohort, regardless of the disease status at the time of evaluation. Older children are at a higher risk for deficient levels of vitamin D.

Threshold of 25(OH)D and consequently adjusted parathyroid hormone reference intervals: data mining for relationship between vitamin D and parathyroid hormone

PURPOSE

By recruiting reference population, we aimed to (1): estimate the 25(OH)D threshold that maximally inhibits the PTH, which can be defined as the cutoff value for vitamin D sufficiency; (2) establish the PTH reference interval (RI) in population with sufficient vitamin D.

METHODS

Study data were retrieved from LIS (Laboratory Information Management System) under literature suggested criteria, and outliers were excluded using Tukey fence method. Locally weighted regression (LOESS) and segmented regression (SR) were conducted to estimate the threshold of 25(OH)D. Multivariate linear regression was performed to evaluate the associations between PTH concentration and variables including 25(OH)D, gender, age, estimated glomerular filtration rate (EGFR), body mass index (BMI), albumin-adjusted serum calcium (aCa), serum phosphate(P), serum magnesium(Mg), and blood collection season. Z test was adopted to evaluate whether the reference interval should be stratified by determinants such as age and gender.

RESULTS

A total of 64,979 apparently healthy subjects were recruited in this study, with median (Q1, Q3) 25(OH)D of 45.33 (36.15, 57.50) nmol/L and median (Q1, Q3) PTH of 42.19 (34.24, 52.20) ng/L. The segmented regression determined the 25(OH)D threshold of 55 nmol/L above which PTH would somewhat plateau and of 22 nmol/L below which PTH would rise steeply. Multivariate linear regression suggested that gender, EGFR, and BMI were independently associated with PTH concentrations. The PTH RI was calculated as 22.17-72.72 ng/L for subjects with 25(OH)D ≥ 55 nmol/L with no necessity of stratification according to gender, age, menopausal status nor season.

CONCLUSION

This study reported 25(OH)D thresholds of vitamin D sufficiency at 55 nmol/L and vitamin D deficiency at 22 nmol/L, and consequently established PTH RIs in subjects with sufficient vitamin D for northern China population for the first time.

Endocrine Health and Health Care Disparities in the Pediatric and Sexual and Gender Minority Populations: An Endocrine Society Scientific Statement

Endocrine care of pediatric and adult patients continues to be plagued by health and health care disparities that are perpetuated by the basic structures of our health systems and research modalities, as well as policies that impact access to care and social determinants of health. This scientific statement expands the Society's 2012 statement by focusing on endocrine disease disparities in the pediatric population and sexual and gender minority populations. These include pediatric and adult lesbian, gay, bisexual, transgender, queer, intersex, and asexual (LGBTQIA) persons. The writing group focused on highly prevalent conditions-growth disorders, puberty, metabolic bone disease, type 1 (T1D) and type 2 (T2D) diabetes mellitus, prediabetes, and obesity. Several important findings emerged. Compared with females and non-White children, non-Hispanic White males are more likely to come to medical attention for short stature. Racially and ethnically diverse populations and males are underrepresented in studies of pubertal development and attainment of peak bone mass, with current norms based on European populations. Like adults, racial and ethnic minority youth suffer a higher burden of disease from obesity, T1D and T2D, and have less access to diabetes treatment technologies and bariatric surgery. LGBTQIA youth and adults also face discrimination and multiple barriers to endocrine care due to pathologizing sexual orientation and gender identity, lack of culturally competent care providers, and policies. Multilevel interventions to address these disparities are required. Inclusion of racial, ethnic, and LGBTQIA populations in longitudinal life course studies is needed to assess growth, puberty, and attainment of peak bone mass. Growth and development charts may need to be adapted to non-European populations. In addition, extension of these studies will be required to understand the clinical and physiologic consequences of interventions to address abnormal development in these populations. Health policies should be recrafted to remove barriers in care for children with obesity and/or diabetes and for LGBTQIA children and adults to facilitate comprehensive access to care, therapeutics, and technological advances. Public health interventions encompassing collection of accurate demographic and social needs data, including the intersection of social determinants of health with health outcomes, and enactment of population health level interventions will be essential tools.

Determination of Vitamin K1, MK-4, MK-7, and D Levels in Human Serum of Postmenopausal Osteoporosis Women Based on High Stability LC-MS/MS: MK-7 May Be a New Marker of Bone Metabolism

INTRODUCTION

Vitamin K (VK) as well as vitamin D (VD) plays an important role in osteoporosis. Vitamin K1 (VK1), vitamin K2 (VK2, menaquinone-4 (MK-4), and menaquinone-7 (MK-7)) are significant for the metabolism of skeletal muscle. 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 (25(OH)D2 and 25(OH)D3) reflect circulating VD levels. More sensitive measurements remain to be developed. In the present study, a new high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of VK1, VK2 (MK-4 and MK-7), as well as 25(OH)D2 and 25(OH)D3 levels in human serum.

METHODS

We developed a simple LC-MS/MS method for the determination of VK1, MK-4, MK-7, 25(OH)D2, and 25(OH)D3 levels in human serum and validated the method in a study cohort of 200 patients divided into the premenopausal women group and postmenopausal osteoporosis patient group.

RESULTS

The overall precision (coefficient of variation) ranged from 2.66 to 10.11% in the specified working range (0.05-5 ng/mL) for VK1, MK-4, and MK-7. Serum VK1, MK-4, and MK-7 levels in postmenopausal women with osteoporosis were 1.187 ± 0.094 ng/mL, 0.058 ± 0.009 ng/mL, and 0.885 ± 0.064 ng/mL, respectively (mean ± standard deviation). Serum VK1, MK-4, and MK-7 levels in premenopausal women were 1.143 ± 0.103 ng/mL, 0.028 ± 0.003 ng/mL, and 1.553 ± 0.226 ng/mL, respectively. Serum 25(OH)D2 and 25(OH)D3 levels in postmenopausal women with osteoporosis were 0.757 ± 0.056 ng/mL and 11.72 ± 0.632 ng/mL, respectively. Serum 25(OH)D2 and 25(OH)D3 levels in premenopausal were 1.793 ± 0.575 ng/mL and 12.42 ± 1.069 ng/mL, respectively.

CONCLUSION

A new LC-MS/MS method for determination of serum VK and VD levels was evaluated and validated. MK-7 in plasma decreased earlier than VD in postmenopausal osteoporosis patients. MK-7 status is significantly associated with osteoporosis and could be considered a predictable biomarker in the diagnosis of osteoporosis in postmenopausal women.

Greater Gestational Vitamin D Status is Associated with Reduced Childhood Behavioral Problems in the Environmental Influences on Child Health Outcomes Program

BACKGROUND

Vitamin D deficiency is common in pregnancy. Vitamin D plays an important role in the developing brain, and deficiency may impair childhood behavioral development.

OBJECTIVES

This study examined the relationship between gestational 25(OH)D concentrations and childhood behavior in the Environmental influences on Child Health Outcomes (ECHO) Program.

METHODS

Mother-child dyads from ECHO cohorts with data available on prenatal (first trimester through delivery) or cord blood 25(OH)D and childhood behavioral outcomes were included. Behavior was assessed using the Strengths and Difficulties Questionnaire or the Child Behavior Checklist, and data were harmonized using a crosswalk conversion. Linear mixed-effects models examined associations of 25(OH)D with total, internalizing, and externalizing problem scores while adjusting for important confounders, including age, sex, and socioeconomic and lifestyle factors. The effect modification by maternal race was also assessed.

RESULTS

Early (1.5-5 y) and middle childhood (6-13 y) outcomes were examined in 1688 and 1480 dyads, respectively. Approximately 45% were vitamin D deficient [25(OH)D < 20 ng/mL], with Black women overrepresented in this group. In fully adjusted models, 25(OH)D concentrations in prenatal or cord blood were negatively associated with externalizing behavior T-scores in middle childhood [-0.73 (95% CI: -1.36, -0.10) per 10 ng/mL increase in gestational 25(OH)D]. We found no evidence of effect modification by race. In a sensitivity analysis restricted to those with 25(OH)D assessed in prenatal maternal samples, 25(OH)D was negatively associated with externalizing and total behavioral problems in early childhood.

CONCLUSIONS

This study confirmed a high prevalence of vitamin D deficiency in pregnancy, particularly among Black women, and revealed evidence of an association between lower gestational 25(OH)D and childhood behavioral problems. Associations were more apparent in analyses restricted to prenatal rather than cord blood samples. Interventions to correct vitamin D deficiency during pregnancy should be explored as a strategy to improve childhood behavioral outcomes.

Traumatic orthopaedic motor vehicle injuries: Are there age and sex differences in pedestrian and cyclist accidents in a major urban center?

INTRODUCTION

Injuries caused by road traffic have become the leading cause of death in people aged 5 to 29 years, with pedestrians and cyclists being disproportionately affected. Research has demonstrated age and sex differences in road accidents in European populations. The purpose of this study was to determine age and sex-specific differences in pedestrian and cyclist accidents involving passenger cars at a single Level 1 Trauma Center in a major US metropolitan area.

METHODS

We performed a retrospective chart review of 1,845 patients that presented to a single level 1 trauma center from January 1, 2016 - October 1st, 2021, and were involved in a motor vehicle vs. pedestrian or motor vehicle vs. cyclist accidents. Demographics, injury pattern, abbreviated injury scores (AIS), and hospital stay were analyzed, and the data was stratified by pedestrian vs. cyclist, biological sex, and race. Chi square analysis, t tests, and binomial logistic regression was used to examine sex and age-based differences.

RESULTS

Pedestrian vs. motor vehicle collisions (N = 1359, 74%) occurred more frequently than cyclists (N = 475, 26%) with an overall mortality rate of 6%. The mean age of pedestrians and cyclists was 39 and 42 years of age, respectively. Overall, more female than male patients had hand (mean=0.05 vs. 0.02) (p = 0.03) and pelvis fractures (mean 0.28 vs. 0.19) (p = 0.007). Females had a 1.2 times higher likelihood of getting a pelvis fracture than males (95% CI, 1.06 to 1.43). Linear regression analysis found a statistically significant relationship between older age and increased AIS severity (p < .001). Half of our sample consisted of Black patients (49.6% Black vs. 42.1% white).

CONCLUSION

Female pedestrians and cyclists are at increased risk of obtaining pelvis fractures when in a traumatic road accident than males, regardless of age stratification, and age is a predictor of injury severity. Our study also found that race-based differences exist, with Black patients being injured more frequently. Further research is needed to better understand demographics at risk for traumatic road accidents, as well as evaluation of city infrastructure for biking and walking.

Serum Vitamin D status and VDR (FokI) polymorphism association study in Pakistani females with breast cancer

Background

Breast cancer is most common in Pakistani women at young age compared to West where it is most common after 60 years of age. Variations in genes controlling vitamin D activity would play a role in determining the risk of breast cancer in women at early age.

Purpose

To determine the association of vitamin D receptors (VDR) gene polymorphisms (FokI) with breast cancer risk in Pakistani women.

Methods

FokI polymorphisms were studied through the polymerase chain reaction-restriction fragment length polymorphism technique on blood samples of 300 breast cancer and 300 healthy women.

Results

This study found that circulating level of 25(OH)D3 was significantly lower among breast cancer patients as well as healthy subjects. Patients with large tumor size had significantly lower vitamin D levels. VDR FokI genotypes were significantly distributed (P ≤ 0.00001) in Pakistani women with newly diagnosed breast cancer. A significant association between different FokI genotypes and circulating levels of 25(OH)D3 was found. Patients with FF genotype was significantly (P < 0.0001) associated with higher risk of breast cancer (OR 8.9, 95% CI 0.17-0.45) compared to Ff and ff genotype.

Conclusion

VDR gene FokI polymorphism was associated with plasma vitamin D level and significant differences found in mean serum vitamin D levels between genotype groups of FokI. The study concluded that FokI might be one of the contributors to increase relative risk of breast cancer in Pakistani women.

Effects of vitamin D supplementation on the regulation of blood lipid levels in prediabetic subjects: A meta-analysis

This meta-analysis aimed to systematically investigate whether vitamin D supplementation reduces blood lipid—total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), and triglyceride (TG)—levels in prediabetic individuals. Pubmed, Web of Science, Cochrane Library, Embase, CNKI, and WANFANG databases were searched for studies published before 13 February 2022 (including 13 February 2022). Five articles were included. The results showed that vitamin D intervention led to a significant reduction in TG compared with control or placebo treatment (−0.42 [−0.59, −0.25], P &lt; 0.001). Subgroup analyses showed that this effect was particularly significant among the studies that included obese subjects (−0.46 [−0.65, −0.28], P &lt; 0.001), the studies that also included men (not only women) (−0.56 [−0.78, −0.34], P &lt; 0.001), and the studies with intervention durations longer than 1 year (−0.46 [−0.65, −0.28], P &lt; 0.001). Both relatively low doses of 2,857 IU/day (−0.65 [−0.92, −0.38], P &lt; 0.001) and relatively high doses of 8,571 IU/day (−0.28 [−0.54, −0.02] P = 0.04) of vitamin D supplementation reduced TG levels, and the effect was observed both in Northern Europe (−0.65 [−0.92, −0.38], P &lt; 0.001) and Asian (−0.25 [−0.48, −0.03], P = 0.03) country subgroups. No significant effects on TC, HDL-C, and LDL-C were shown. In conclusion, vitamin D supplementation might beneficially affect TG levels in individuals with prediabetes. Particularly longer durations of treatment, more than 1 year, with doses that correct vitamin deficiency/insufficiency, can have a beneficial effect. This meta-analysis was registered at www.crd.york.ac.uk/prospero (CRD42020160780).

Serum 25-Hydroxyvitamin D concentrations are inversely associated with all-cause mortality among Koreans: a nationwide cohort study

Evidence on the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and all-cause and cause-specific mortality in Asians, especially Koreans, is limited. We hypothesized that high concentrations of 25(OH)D are associated with lower all-cause and cause-specific mortality in the general Korean population. This study included 27,846 adults participating in the Fourth and Fifth Korean National Health and Nutrition Examination Survey 2008-2012, followed up through December 31, 2019. Hazard ratios (HR) and 95% confidence intervals (CIs) for mortality from all causes, cardiovascular disease (CVD), and cancer were estimated using multivariable-adjusted Cox proportional hazards regression. The weighted mean serum 25(OH)D of study participants was 17.77 ng/mL; 66.5% had vitamin D deficiency (<20 ng/mL) and 94.2% had insufficient vitamin D (<30 ng/mL). During a median follow-up of 9.4 years (interquartile range, 8.1-10.6 years), 1680 deaths were documented, including 362 CVD deaths and 570 cancer deaths. Serum 25(OH)D levels ≥30 ng/mL were inversely associated with all-cause mortality (HR, 0.57; 95% CI, 0.43-0.75) compared with serum 25(OH)D levels <10 ng/mL. Based on the quartile cutoffs of serum 25(OH)D concentration, the highest quartile of serum 25(OH)D concentration (≥21.8 ng/mL) was associated with the lowest all-cause mortality (HR, 0.72; 95% CI, 0.60-0.85; P trend < .001), and CVD mortality (HR, 0.60; 95% CI, 0.42-0.85; P trend = .006). No association with cancer mortality outcome was found. In conclusion, higher serum 25(OH)D levels were associated with lower all-cause mortality in the general Korean population. An additional association was found between higher quartile of serum 25(OH)D and lower CVD mortality.

Vitamin D and risk of hypertension among Black women

Evidence of an association between plasma 25-hydroxyvitamin D [25(OH)D] levels and risk of hypertension, predominantly from studies of White individuals, suggests an inverse relationship. Limited data are available on Black individuals, who are more likely to have vitamin D deficiency. In the Black Women's Health Study (BWHS), a prospective study of 59 000 self-identified Black women from across the US, we assessed levels of a validated predicted vitamin D score in relation to incident hypertension. We followed 42 239 participants who were free of cardiovascular disease and cancer from 1995 to 2019, during which time 19 505 incident cases of hypertension were identified. Cox proportional hazards model were used to calculate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of predicted vitamin D with the risk of incident hypertension. In age-adjusted analyses, there was a strong inverse dose-response association between predicted vitamin D score and hypertension risk, with an HR of .66 (95% CI: .63-.68, p trend < .0001) for the highest quartile of predicted vitamin D relative to the lowest. After control for potential confounders including body mass index, physical activity, and cigarette smoking, the HR was attenuated to .91 (95% CI: .87-.95, p trend = .002). In this prospective cohort study of Black women, predicted vitamin D score was weakly inversely associated with the incidence of hypertension. This observed association may reflect an inability to fully control for confounding factors.

The Relationship Between Serum 25-Hydroxyvitamin D Levels and Osteoporosis in Postmenopausal Women

Background

Vitamin D status is indicated by serum 25-hydroxyvitamin D [25(OH)D] levels, and the positive effects of high levels of vitamin D on bone mineral density (BMD) have not been ascertained. Therefore, we performed a study to analyze the association between serum 25(OH)D levels and osteoporosis in postmenopausal women.

Methods

We conducted a cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES). Multiple logistic regression was used to explore the relationship between serum 25(OH)D and osteoporosis of total femur, femoral neck and lumbar spine, with stratified analyses for age (<65 and ≥65 years), BMI (<25, 25 to <30, ≥30 kg/m²) and survey months (winter months and summer months).

Results

In total, 2058 participants were enrolled in our study. In the fully adjusted model, compared with serum 25(OH)D levels <50 nmol/L, the odds ratios (ORs) and 95% confidence intervals (CIs) of serum 25(OH)D 50-<75 nmol/L and ≥75 nmol/L were 0.274 (0.138, 0.544) and 0.374 (0.202, 0.693) in osteoporosis of total femur, 0.537 (0.328, 0.879) and 0.583 (0.331, 1.026) in osteoporosis of femoral neck, and 0.614 (0.357, 1.055) and 0.627 (0.368, 1.067) in osteoporosis of lumbar spine, respectively. The protective effect of high 25(OH)D was observed at all three skeletal sites in those ≥65 years of age, whereas it was observed only in the total femur in those <65 years of age.

Conclusion

In conclusion, adequate vitamin D may reduce the risk of osteoporosis in postmenopausal women in the United States, especially in those aged 65 years and older. More attention should be given to serum 25 (OH) D levels to prevent osteoporosis.

The association of parathyroid hormone with serum 25-hydroxyvitamin during pregnancy

It is currently debated whether vitamin D requirements during pregnancy differ from those during non-gravid states. In current analyses, we aimed to determine the best model for the association between PTH and serum 25-hydroxyvitamin D (25(OH)D) and the threshold for circulating 25(OH)D at which serum parathyroid hormone (PTH) is suppressed. This multicenter prospective cross-sectional study was conducted on 227 Iranian pregnant women aged 15-45 years in their third trimester of pregnancy. The locally weighted smoothing scatter plot (LOWESS) was used to determine the curvilinear shape of the 25(OH)D/PTH relationship. Linear and non-linear methods were employed to determine the best fit and cut-point for serum 25(OH)D concentration. The median serum 25(OH)D and corresponding serum PTH concentration were 17⋅26 (13⋅44-23⋅08) ng/ml and 19⋅46 (15⋅08-25⋅04) pg/ml in our study population, respectively. The LOWESS curve suggested a non-linear and monotonic with a negative slope relation between PTH (pg/ml) and serum 25(OH)D (ng/ml). The optimal model for the association between PTH and serum 25(OH)D was a one-term fractional polynomial (FP1) (AIC = 1640⋅463). The FP1 analysis identified the 25(OH)D threshold of 12⋅48 ng/ml at which serum PTH rapidly rose. The expected degree of PTH stimulation seems to have a linear trend as 25(OH)D falls below 40 ng/ml. 25(OH)D (ng/ml) and PTH (pg/ml) had a non-linear and monotonic relationship with a negative slope. Our data suggest that a 25(OH)D threshold of 12⋅48 ng/ml is sufficient for parathyroid hormone suppression, which could be used to screen for deficient individuals.

Effect of vitamin D metabolites on bone histomorphometry in healthy black and white women: An attempt to unravel the so-called vitamin D paradox in blacks

An apparent vitamin D paradox, characterized by lower serum 25-hydroxyvitamin D (25(OH)D) levels and higher bone mineral density, is present in black population. In contrast, blacks have higher serum 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels. The effect of 1,25(OH)₂D on the skeleton is not fully understood. We examined serum 25(OH)D, 1,25(OH)₂D and bone histomorphometry in 50 black and white women (25 each) matched for age, menstrual status, and BMI. Histomorphometric indices related to bone structure, remodeling and mineralization were measured in cancellous bone in iliac bone biopsies. Data analyses led to the following results: 1) serum 25(OH)D was significantly lower and 1,25(OH)₂D was significantly higher in black than in white women, but neither blacks nor whites revealed significant correlation between these two vitamin D metabolites. 2) there was no significant difference in PTH levels between blacks and whites. 3) except for greater trabecular thickness (Tb.Th) in blacks, there were no significant differences in other histomorphometric variables between the two ethnic groups. 4) osteoid surface (OS/BS), unlabeled osteoid surface (ulOS/BS), and osteoblast surface (ObS/BS) significantly correlated with serum 1,25(OH)₂D levels. We conclude that lower serum 25(OH)D levels in blacks do not impair bone structure and remodeling, nor decrease bone mineralization. Higher serum 1,25(OH)₂D levels in blacks may help preserve bone mass by stimulating bone formation via increasing osteoblast number and function, but moderately inhibit terminal bone mineralization as shown by higher ulOS/BS.

The Efficacious Benefit of 25-Hydroxy Vitamin D to Prevent COVID-19: An In-Silico Study Targeting SARS-CoV-2 Spike Protein

The environment has rapidly looked at proven specialist task forces in the aftermath of the COVID-19 pandemic to build public health policies and measures to mitigate the effects of emerging coronaviruses. According to the researchers, taking 10 μg of 25-hydroxy vitamin D daily is recommended to keep us safe. There have been several studies recently indicating that there is a reduced risk of contracting Coronavirus by 25-hydroxy vitamin D consumption, even though there is no scientific data to prove that one would not affect the COVID-19 viral infection by 25-hydroxy vitamin D consumption. In this regard, the present study investigates the important literature and the role of 25-hydroxy vitamin D to prevent COVID-19 infection by conducting an in-silico study with SARS-CoV-2 spike protein as a target. Lopinavir, a previously reported drug candidate, served as a reference standard for the study. MD simulations were carried out to improve predictions of receptor-ligand complexes which offer novelty and strength to the current study. MD simulation protocols were explored and subjected to 25-hydroxy vitamin D and a known drug, Lopinavir. Comparison of ligands at refined models to the crystal structure led to promising results. Appropriate timescale simulations have been used to understand the activation mechanism, the role of water networks for receptor function, and the ligand binding process. Furthermore, MD simulations in combination with free energy calculations have also been carried out for lead optimization, evaluation of ligand binding modes, and assessment of ligand selectivity. From the results, 25-hydroxy vitamin D was discovered to have the vital interaction and highest potency in LBE, lower RMSD, and lower inhibition intensity similar to the standard. The findings from the current study suggested that 25-hydroxy vitamin D would be more effective in treating COVID-19. Compared with Lopinavir, 25-hydroxy vitamin D had the most potent interaction with the putative binding sites of the SARS-CoV-2 spike protein of COVID-19.

Vitamin D status and prevalence of metabolic syndrome by race and Hispanic origin in US adults: findings from the 2007-2014 NHANES

BACKGROUND

Vitamin D status has been found to be inversely associated with metabolic syndrome (MetS) in some studies. Vitamin D status varies by race and ethnicity, and the association of MetS with vitamin D status in US adults and by race and Hispanic origin has not been evaluated extensively.

OBJECTIVES

We aimed to examine the associations between vitamin D status and MetS overall, and across race and Hispanic origin groups, in a nationally representative sample of US adults who participated in the NHANES from 2007 to 2014.

METHODS

The total sample included 8639 adults, ≥20 y of age. Serum vitamin D was measured using a standardized LC-tandem MS method and was categorized using data-driven tertiles. MetS was defined using measured waist circumference, triglycerides, HDL cholesterol, blood pressure, and fasting glucose. Multivariable logistic regression models were fitted [accounting for sociodemographic and lifestyle factors, dietary supplement use, and BMI (in kg/m2)] to examine the associations of serum vitamin D with MetS among adults overall, and by race and Hispanic origin.

RESULTS

Serum vitamin D in the lowest tertile (≤56 nmol/L) was significantly associated with increased odds of MetS compared with the highest tertile (>77.9 nmol/L) (fully adjusted model OR: 1.85; 95% CI: 1.51, 2.27). Inverse associations were noted for all race-Hispanic origin groups: non-Hispanic white (NHW) (OR: 2.24; 95% CI: 1.67, 3.01), non-Hispanic black (OR: 1.56; 95% CI: 1.06, 2.29), and Hispanic (OR: 1.48; 95% CI: 1.03, 2.14) adults.

CONCLUSIONS

Lower vitamin D status was significantly associated with MetS among US adults after adjusting for sociodemographic and lifestyle factors, dietary supplement use, and BMI. This finding was noted across all race and Hispanic origin groups, although the strength of the association varied, being strongest for NHW adults.

Vitamin D binding protein gene polymorphisms are associated with lower plasma 25-hydroxy-cholecalciferol concentrations in Ethiopian lactating women

Ethiopian women have been reported to have low plasma 25-hydroxy-cholecalciferol (25(OH)D) concentrations despite an abundance of sunshine. Low dietary vitamin D intake, limited skin exposure to sun, and genetics are among factors suggested to affect vitamin D status in this population. In this study (Clinical Trial NCT02210884), we hypothesized that polymorphisms in the vitamin D binding protein (VDBP) gene (rs7041, rs4588) are associated with reduced plasma 25(OH)D concentrations in Ethiopian women. Lactating Ethiopian women (n = 110) were randomly assigned to weekly administration of vitamin D3 (15,000 IU) or a placebo. Plasma 25(OH)D was measured at baseline (within 2 weeks of delivery, before supplementation) and at 3, 6, and 12 months after delivery. Associations between VDBP polymorphism status for rs7041 and rs4588 and plasma 25(OH)D were determined by analysis of variance and multiple linear and logistic regressions. Multiple linear regression with maternal age as a covariate revealed that rs7041 is associated with reduced plasma 25(OH)D (P = .021) and more risk alleles at rs7041 and rs4588 are associated with reduced plasma 25(OH)D (P = .017). Logistic regression models for vitamin D insufficiency showed that additional risk alleles for rs7041 and rs4588 are associated with increased odds ratios (OR = 1.66; 95% CI, 1.10-2.62; P = .019) for plasma 25(OH)D below 40 nmol/L. Supplementation increased plasma 25(OH)D at 3 months in women with fewer risk alleles and across all genotypes at 6 and 12 months. VDBP polymorphisms may contribute to vitamin D insufficiency in Ethiopian lactating women. Furthermore, VDBP polymorphisms may blunt short-term responses to vitamin D supplementation and require longer periods of intervention.

Calcium status assessment at the population level: Candidate approaches and challenges

Inadequate dietary calcium intake is a global public health problem that disproportionately affects low- and middle-income countries. However, the calcium status of a population is challenging to measure, and there are no standard methods to identify high-risk communities even in settings with an elevated prevalence of a disease caused or exacerbated by low calcium intake (e.g., rickets). The calcium status of a population depends on numerous factors, including intake of calcium-rich foods; the bioavailability of the types of calcium consumed in foods and supplements; and population characteristics, including age, sex, vitamin D status, and genetic attributes that influence calcium retention and absorption. The aim of this narrative review was to assess candidate indicators of population-level calcium status based on a range of biomarkers and measurement methods, including dietary assessment, calcium balance studies, hormonal factors related to calcium, and health outcomes associated with low calcium status. Several promising approaches were identified, but there was insufficient evidence of the suitability of any single indicator to assess population calcium status. Further research is required to develop and validate specific indicators of calcium status that could be derived from the analysis of data or samples that are feasibly collected in population-based surveys.

Association between vitamin D serum levels and insulin resistance assessed by HOMA-IR among non-diabetic adults in the United States: Results from NHANES 2007-2014

Insulin resistance, a pathological response to insulin hormone in insulin-dependent cells, is characterized by the presence of high glucose and insulin concentrations. The homeostasis model of insulin resistance (HOMA-IR) is one of the most used indexes to estimate insulin resistance by assessing the fasting glucose and insulin levels. An association was observed between vitamin D levels and insulin resistance, which varied in different ethnic groups, and there is some evidence that vitamin D supplementation could contribute to the improvement of insulin resistance. This study assessed the association between 25-hydroxyvitamin D (25[OH]D) concentration and HOMA-IR in American adults aged 20 years and older, without diabetes and other chronic diseases that can influence insulin resistance. The data from the National Health and Nutrition Examination Survey (NHANES) 2007–2014 were used by exploiting the free and publicly-accessible web datasets. Linear regression models were performed to evaluate the association between serum 25(OH)D concentration and HOMA-IR, and a negative association was observed, which remained significant following the adjustment for age, gender, race/ethnicity, education, body mass index (BMI), physical activity, the season of examination, current smoking, hypertension, the use of drugs which can influence insulin resistance, serum bicarbonates, triglycerides, and calcium and phosphorus levels. Only in non-Hispanic Blacks was this inverse association between vitamin D and HOMA-IR not observed in the fully adjusted model. Further studies are needed to explain the mechanisms of the observed ethnic/racial differences in the association of vitamin D levels with HOMA-IR.

Serum vitamin D and cardiometabolic risk factors in the UK population

Low serum 25-hydroxyvitamin D (25(OH)D) concentrations have been associated with greater adiposity and an adverse cardiometabolic risk profile, yet findings are inconsistent and the role of vitamin D status in cardiovascular disease (CVD) remains uncertain. We aimed to examine the associations between serum 25(OH)D and CVD risk factors in the British population. We analysed data on 2842 subjects aged ≥40 years enrolled in the National Diet and Nutrition Survey (NDNS 2008-2018). Based on serum 25(OH)D concentrations, study subjects were grouped in three categories: vitamin D deficiency (<25 nmol/L), vitamin D insufficiency (25-49 nmol/L) and vitamin D sufficiency status (≥50 nmol/mL). Differences in CVD risk factors between vitamin D deficiency or insufficiency and vitamin D sufficiency status were expressed in standard deviation scores (SDSs) and estimated through weighted multiple linear regression models. We found that vitamin D deficiency was directly associated with BMI, waist circumference, triglycerides and inversely associated with high-density lipoprotein cholesterol (HDL) values. The strongest associations were found between vitamin D deficiency and triglycerides (0.50 SDS, 95% CI: 0.24, 0.77) among men, and vitamin D deficiency and waist circumference (0.70 SDS, 95% CI: 0.56, 0.94), BMI (0.63 SDS, 95% CI: 0.39, 0.88) and triglycerides (0.54 SDS, 95% CI: 0.30, 0.77) among women. When adjusting for BMI the association with triglyceride attenuated (from 0.50 SDS to 0.39 SDS among men and from 0.54 SDS to 0.30 SDS among women). Our data indicates a relationship between inadequate vitamin D status and an adverse CVD risk profile. However, interventional studies are needed to establish possible benefits of vitamin D supplementation on cardiovascular risk. This article is protected by copyright. All rights reserved.

Vitamin D levels in children with cerebral palsy

PURPOSE

The aim of this study was to assess serum vitamin D levels and related factors in children with cerebral palsy (CP).

METHODS

One hundred and nineteen children with CP between the ages of 1 year to 10 years 9 months who were admitted to the children's inpatient rehabilitation unit of a tertiary rehabilitation hospital between January 1, 2017, and December 31, 2018, were included in this study. Demographic and clinical characteristics were obtained from the patient files. CP types and serum 25 hydroxyvitamin D (25OHD) levels were recorded. Gross Motor Function Classification System (GMFCS) was used to assess the functional level.

RESULTS

Mean age was 5.1±2.9 years. Forty-two (35.3%) were girls, 105 (88.3%) were spastic, and 14 (11.7%) were ataxic and mixed type CP. Mean GMFCS level was 4 (IQR:2). Thirty-one (26.1%) were getting extra liquid feed while the rest were eating a normal diet. Mean serum 25OHD level was 27.4±15.7 (3-79) ng/mL. Vitamin D levels were normal in 68 children (57.1%), whereas 36 (30.3%) had vitamin D insufficiency and 15 (12.6%) showed vitamin D deficiency. Those whose serum vitamin D levels were within a normal range had a median age of 3.8 (IQR:4.2) years. On the other hand, mean age was 6.4 (4.3) years for those with low vitamin D level (p <  0.0001). Vitamin D level was 19.8 (21.4) ng/mL in those (n = 88) who had regular diets, whereas it was 31.0 [16] ng/mL in those (n = 31) who were getting extra liquid feed (p = 0.015). There was no statistically significant correlation between vitamin D level and gender, GMFCS, CP type, season or antiepileptic drug treatment. A binary logistic regression model showed that older age and having only regular meals were significant risk factors for low vitamin D.

CONCLUSION

In this study, 42.9% of the children with CP had low vitamin D. Older children with CP or those who had regular diets were higher risk groups in terms of low vitamin D.

Serum 25-Hydroxyvitamin D is Associated With Bone Microarchitecture and Strength in a Multiracial Cohort of Young Adults

PURPOSE

To determine whether 25-hydroxyvitamin D (25-OH D) levels are associated with bone outcomes in a multiracial cohort of young adults.

METHODS

This cross-sectional study included 165 participants (83 men, 82 women, 18-30 years of age) who self-identified as Asian, Black, or White. We measured bone microarchitecture and strength of the distal radius and tibia using high-resolution peripheral quantitative computed tomography. We used linear regression to estimate the association between 25-OH D (ng/mL) and bone measurements, adjusting for race, sex, age, weight, height, calcium intake, physical activity, and season.

RESULTS

A total of 43.6% of participants were 25-OH D deficient (<20 ng/mL) with greater prevalence in Asian (38.9%) and Black (43.1%) compared with White (18.0%) participants (P < 0.001). At the distal radius, 25-OH D was positively associated with cortical area, trabecular density, cortical thickness, cortical porosity, and failure load (P < 0.05 for all). At the distal tibia, higher 25-OH D was associated with higher cortical area, trabecular density, trabecular number, failure load, and lower trabecular separation and cortical density (P < 0.05 for all). After multivariable adjustment, those with 25-OH D deficiency had generally worse bone microarchitecture than those with 25-OH D sufficiency. Black individuals had largely more favorable bone outcomes than Asian and White individuals, despite higher prevalence of 25-OH D deficiency.

CONCLUSIONS

We found a high prevalence of 25-OH D deficiency in a multiracial cohort of young adults. Lower 25-OH D was associated with worse bone outcomes at the distal radius and tibia at the time of peak bone mass, warranting further attention to vitamin D status in young adults.

Vitamin D3 Repletion Improves Vascular Function, as Measured by Cardiorenal Biomarkers in a High-Risk African American Cohort

Background: 25-hydroxy vitamin D (Vit D)-deficiency is common among patients with chronic kidney disease (CKD) and contributes to cardiovascular disease (CVD). African Americans (AAs) suffer disproportionately from CKD and CVD, and 80% of AAs are Vit D-deficient. The impact of Vit D repletion on cardio-renal biomarkers in AAs is unknown. We examined Vit D repletion on full-length osteopontin (flOPN), c-terminal fibroblast growth factor-23 (FGF-23), and plasminogen activator inhibitor-1 (PAI-1), which are implicated in vascular and kidney pathology. Methods: We performed a randomized, placebo-controlled study of high-risk AAs with Vit D deficiency, treated with 100,000 IU Vit D3 (cholecalciferol; n = 65) or placebo (n = 65) every 4 weeks for 12 weeks. We measured kidney function (CKD-EPI eGFR), protein-to-creatinine ratio, vascular function (pulse wave velocity; PWV), augmentation index, waist circumference, sitting, and 24-h-ambulatory blood pressure (BP), intact parathyroid hormone (iPTH) and serum calcium at baseline and study end, and compared Vit D levels with laboratory variables. We quantified plasma FGF-23, PAI-1, and flOPN by enzyme-linked immunosorbent assay. Multiple regression analyzed the relationship between log flOPN, FGF-23, and PAI-1 with vascular and renal risk factors. Results: Compared to placebo, Vit D3 repletion increased Vit D3 2-fold (p < 0.0001), decreased iPTH by 12% (p < 0.01) and was significantly correlated with PWV (p < 0.009). Log flOPN decreased (p = 0.03), log FGF-23 increased (p = 0.04), but log PAI-1 did not change. Multiple regression indicated association between log flOPN and PWV (p = 0.04) and diastolic BP (p = 0.02), while log FGF-23 was associated with diastolic BP (p = 0.05), and a trend with eGFR (p = 0.06). Conclusion: Vit D3 repletion may reduce flOPN and improve vascular function in high risk AAs with Vit D deficiency.

Prevalence of osteoporosis in osteoarthritis: a systematic review and meta-analysis

Data are contradictory regarding the relationship between osteoarthritis (OA) and osteoporosis (OP) with some studies showing the increased risk of OP in OA. The study was conducted to determine whether OP prevalence is increased in patients with OA, compared to age and sex-matched population. MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library (inception-2019) were searched for studies reporting the frequency, rate, prevalence, incidence, risk, or excess risk of OP in patients with OA compared to age and sex-matched population. Estimates were combined using a random effects model. Consistency was evaluated using the I² statistic. Articles with fewer than 200 participants were excluded. Of 2772 articles, 49 had full article screening, and 8 articles met the inclusion criteria. Other articles reporting mean BMD and not OP were excluded. In women, 998 participants with OA were compared with 1903 controls. The pooled estimate of the odds ratio for prevalence of OP vs general matched population was not statistically different. In men, 136 participants with OA were compared with 682 controls. The results did not show a statistically significant difference in the frequency of OP in OA in men. According to the site of bone mineral density measurement, a higher prevalence of OP at lumbar spine was found in both men and women. The frequency of OP overall in participants with OA was not different, except for a higher prevalence of OP in lumbar spine in both men and women compared to the matched controls.

Reconsidering vitamin D optimal values based on parathyroid hormone levels in a North Algerian cohort: stratification by gender and season

"Health-based threshold value" is used to define the optimal cutoff of vitamin D. This approach is based on the hypothesis of a secondary hyperparathyroidism associated with hypovitaminosis D. We define the optimal values in a North Algerian population. The optimal value is 25.0 ng/ml in men and 30.0 ng/ml in women.

PURPOSE/INTRODUCTION

There is no consensus defining the vitamin D optimal values. The aim of this study is to establish vitamin D optimal values in the Northern Algerian population, based on its skeletal effects as represented by the inverse relationship between 25-hydroxy vitamin D (25(OH) D) and parathyroid hormone (PTH).

METHODS

451 healthy volunteers of both genders, aged 19 to 79 years, were enrolled in a cross-sectional study conducted at the medical analysis laboratory of the University Hospital of Blida, Algeria. 25(OH) D was assessed by a sequential competitive immuno-fluoroassay technique. Determination of vitamin D optimal values was performed based on the kinetic relationship between 25(OH) D and PTH, as explored by inverse nonlinear regression on a spline plots curve. The optimal value represents the 25(OH) D level at which PTH ceases to increase and reaches a virtual plateau.

RESULTS

In men and women, respectively, the 25 (OH) D thresholds are estimated at 25.0 ng/ml and 30 ng/ml, above this value, PTH stabilizes in a virtual plateau, estimated at 22.3 pg/ml and 26.8 pg/ml. In warm and cold seasons, respectively, the 25 (OH) D cut-offs are estimated at 30.0 ng/ml and 25.0 ng/ml, from these values, the PTH stabilizes in a virtual plateau, estimated at 21.5 pg/ml and 27.7 pg/ml.

CONCLUSION

In this study, the optimal values of 25(OH) D were defined for the first time in a North Algerian adult population. The optimal value is 25.0 ng/ml in men and 30.0 ng/ml in women.

Vitamin D is associated with body composition and fat intake, but not with cardiometabolic parameters in adults with obesity

Adults with obesity are at higher risk for developing hypovitaminosis D. Some studies suggest that reduced levels of serum 25-hydroxyvitamin D (25(OH)D) may also be related to disorders in cardiometabolic parameters. However, because of the association between 25(OH)D and obesity, we hypothesized that body composition can be a confounding factor in the association of 25(OH)D with cardiometabolic parameters, and that 25(OH)D is inversely associated with body composition and cardiometabolic parameters and directly associated with fat intake. The aim of this study was to analyze the associations between 25(OH)D with body composition, fat intake, and cardiometabolic parameters in adults with obesity. This cross-sectional study consisted of 52 adults with obesity (61.53% female; 37.50 ± 6.88 years; body mass index [BMI]: 33.60 ± 2.89 kg/m²). Cardiometabolic parameters (fasting blood glucose, insulin resistance index, C-reactive protein, blood pressure, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and cholesterol), body mass, BMI, waist circumference, body fat percentage, and fat intake were evaluated. Body mass was negatively associated with 25(OH)D (β = -0.108; P = .048; and R² = 0.090) and BMI (β = -0.621; P = .031; and R² = 0.103), both adjusted for fat intake. 25(OH)D was positively associated with fat intake (β = 0.129; P = .045 and R² = 0.078) adjusted for sex, age, and skin color. Cardiometabolic parameters were not associated with 25(OH)D, even after adjusted by body composition variables. However, the high prevalence of hypovitaminosis D (75%) and the negative association between 25(OH)D and body composition reinforce the importance of analyzing and monitoring vitamin D status in this population.

Perspective: School Meal Programs Require Higher Vitamin D Fortification Levels in Milk Products and Plant-Based Alternatives-Evidence from the National Health and Nutrition Examination Surveys (NHANES 2001-2018)

Poor vitamin D status impairs bone growth and immune defense in school-aged children and adolescents, particularly in minorities. Vitamin D insufficiency/deficiency increases the risk of acute viral respiratory infection, underscoring the need for adequate vitamin D intakes during school sessions when viral exposure may be greatest. We studied available vitamin D-related survey data and published findings based on NHANES (2001-2018) to assess the dependency of vitamin D status {25-hydroxyvitamin D [25(OH)D]; in nmol/L} on vitamin D intake (μg/d) in elementary school-aged children (4-8 y), middle school children (9-13 y), and high school adolescents (14-18 y). We sought evidence supporting the need for school programs to facilitate vitamin D adequacy. Usual vitamin D intakes from food and beverages by children/adolescents (NHANES 2015-2018) examined at the 50th percentile intake by race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic) showed all age groups consumed less than half of the Estimated Average Requirement (EAR) for vitamin D (10 μg/d), independent of race/ethnicity. NHANES (2001-2010) analyses show evidence of lower vitamin D status in school-aged children that is linked to lower intakes of fortified milk varying over race/ethnicity and age. Adolescents had lower vitamin D status and milk intake than younger children. A total of 22-44% of vitamin D intakes occurred away from home, with larger percentages of total intakes at breakfast and lunch, at times consistent with school meals. Ever-present inadequate vitamin D intakes with a large percentage consumed away from home together with well-established benefits to growth, bone, and immune defense from enriched vitamin D-fortified milk in school intervention trials provide strong justification to require enriched vitamin D-fortified foods in school meals. An easy to implement plan for improving vitamin D intakes is possible through the FDA's amendment allowing higher vitamin D fortification levels of dairy and plant-based milk alternatives that could increase vitamin D intakes beyond the EAR with just 2 daily servings.

Vitamin D Metabolite Ratio in Pregnant Women with Low Blood Vitamin D Concentrations Is Associated with Neonatal Anthropometric Data

Existing evidence on the correlation between maternal vitamin D concentrations and birth outcomes is conflicting. Investigation of these associations requires accurate assessment of vitamin D status, especially in individuals with low 25-hydroxyvitamin D (25(OH)D) concentrations. This study examined the correlations between birth outcomes and the maternal vitamin D metabolite ratio (VMR) 1 (defined as the ratio of 24,25(OH)2D3 to 25(OH)D) and VMR2 (defined as the ratio of 3-epi-25(OH)D3 to 25(OH)D) using data from the Japan Environment and Children's Study at Chiba Regional Center. A total of 297 mother-neonate pairs were analyzed. Using liquid chromatography-tandem mass spectrometry, we measured 25(OH)D2, 25(OH)D3, 24,25(OH)2D3, and 3-epi-25(OH)D3 concentrations in maternal serum samples. These data were analyzed in relation to birth anthropometric data using multivariable linear regression. Of the study participants, 85.2% showed insufficient vitamin D concentrations. VMR1 was strongly correlated with 25(OH)D concentrations, whereas VMR2 showed a weak correlation. Only VMR2 was associated with all anthropometric data. VMR2 in pregnant women with low vitamin D blood concentrations is a useful marker for neonatal anthropometric data and is independent of 25(OH)D. Accurate measurement of vitamin D metabolites could help better understand the effects of vitamin D on birth outcomes.

Vitamin D, skin filaggrin, allergic sensitization, and race

BACKGROUND

In addition to its involvement in both the innate and adaptive immune systems, vitamin D has been found to affect keratinocyte function and proliferation, suggesting a possible role for vitamin D in cutaneous allergic sensitization.

OBJECTIVE

To explore the role of circulating vitamin D levels in allergic sensitization.

METHODS

Serum 25-hydroxyvitamin D (25(OH)D) levels were measured in a subset of children (N = 323) enrolled in the Mechanisms of Progression of Atopic Dermatitis to Asthma in Children cohort, a prospective early life cohort of children with atopic dermatitis. Allergic sensitization was determined using skin prick testing, and FLG expression in the keratinocytes was measured by quantitative polymerase chain reaction. Multiple Poisson regression was used to evaluate interaction effects between serum 25(OH)D levels and FLG expression with sensitization load as the outcome.

RESULTS

Black participants had significantly lower mean levels of serum 25(OH)D compared with non-Black participants (29.3 vs 32.9 ng/mL; P < .001). FLG expression and sensitization load were negatively correlated in non-Black participants with 25(OH)D levels less than 27.2 ng/mL (Rho = -0.45; P = .02). No association between FLG expression and sensitization load was found in Black participants or participants with 25(OH)D levels greater than or equal to 27.2 ng/mL. Multiple Poisson regression models confirmed that 25(OH)D levels interact with FLG expression to affect sensitization load in non-Black participants.

CONCLUSION

Despite lower vitamin D levels in Black participants, sensitization load was associated with nonlesional skin FLG expression in non-Black, but not Black, children with low vitamin D levels. Thus, a complex interplay of factors determines the impact of vitamin D on allergic sensitization.

Prevalence of vitamin D deficiency and association with parathyroid hormone

Objectives

We evaluated the prevalence of 25-hydroxyvitamin D (25-(OH)D) deficiency in our setting according to season, sex, and age. We also studied the association with parathyroid hormone (PTH) levels.

Methods

The study population comprised all patients with requests for assessment of 25-(OH)D between January 1 and December 31, 2018, as registered in the database of the laboratory information system. Major exclusion criteria were pediatric samples (<18 years) and factors affecting 25-(OH)D and/or PTH levels (i.e., kidney injury, liver disease, PTH disorders).

Results

Among 33,601 patients (24,028 women, 9,573 men), the prevalence of 25-(OH)D deficiency was 48%. Prevalence was greater in males than in females (53% vs. 46%). By age group, deficiency was more prevalent in quartile 1 (Q1, 74-87 years) and less prevalent in quartile 2 (Q2, 60-73 years). By season, deficiency was greater in spring (nonsignificant differences with respect to winter) and lower in summer. The association between 25-(OH)D and PTH was assessed in 9,368 persons. Linear regression analysis showed a weak association (coefficient - 0.303). Multiple logistic regression analysis revealed a significant association between 25-(OH)D deficiency and increased PTH (Odds ratio (OR), 1.63). Other risk factors for increased PTH include female sex (OR, 1.27), season (winter, OR 1.63, spring OR 1.16), and age (quartile 1, OR, 3).

Conclusions

The prevalence of 25-(OH)D deficiency differed according to sex, age, and season of the year. Furthermore, elevation of PTH is mainly influenced by low 25-(OH)D, female sex, season, and age.

Dietary Supplements for Athletic Performance in Women: Beta-Alanine, Caffeine, and Nitrate

Beta-alanine, caffeine, and nitrate are dietary supplements generally recognized by the sport and exercise science community as evidence-based ergogenic performance aids. Evidence supporting the efficacy of these supplements, however, is greatly skewed due to research being conducted primarily in men. The physiological differences between men and women, most notably in sex hormones and menstrual cycle fluctuations, make generalizing male data to the female athlete inappropriate, and potentially harmful to women. This narrative review outlines the studies conducted in women regarding the efficacy of beta-alanine, caffeine, and nitrate supplementation for performance enhancement. Only nine studies on beta-alanine, 15 on caffeine, and 10 on nitrate in healthy women under the age of 40 years conducted in normoxia conditions were identified as relevant to this research question. Evidence suggests that beta-alanine may lower the rate of perceived exertion and extend training bouts in women, leading to greater functional adaptations. Studies of caffeine in women suggest the physiological responder status and caffeine habituation may contribute to caffeine's efficacy, with a potential plateau in the dose-response relationship of performance enhancement. Nitrate appears to vary in influence based on activity type and primary muscle group examined. However, the results summarized in the limited literature for each of these three supplements provide no consensus on dosage, timing, or efficacy for women. Furthermore, the literature lacks considerations for hormonal status and its role in metabolism. This gap in sex-based knowledge necessitates further research on these ergogenic supplements in women with greater considerations for the effects of hormonal status.

Haplotypes in the GC, CYP2R1 and CYP24A1 Genes and Biomarkers of Bone Mineral Metabolism in Older Adults

Candidate gene studies have analyzed the effect of specific vitamin D pathway genes on vitamin D availability; however, it is not clear whether genetic variants also affect overall bone metabolism. This study evaluated the association between genetic polymorphisms in GC, CYP2R1 and CYP24A1 and serum levels of total 25(OH)D, iPTH and other mineral metabolism biomarkers (albumin, total calcium and phosphorus) in a sample of 273 older Spanish adults. We observed a significant difference between CYP2R1 rs10741657 codominant model and total 25(OH)D levels after adjusting them by gender (p = 0.024). In addition, the two SNPs in the GC gene (rs4588 and rs2282679) were identified significantly associated with iPTH and creatinine serum levels. In the case of phosphorus, we observed an association with GC SNPs in dominant model. We found a relationship between haplotype 2 and 25(OH)D levels, haplotype 4 and iPTH serum levels and haplotype 7 and phosphorus levels. In conclusion, genetic variants in CYP2R1 and GC could be predictive of 25(OH)D and iPTH serum levels, respectively, in older Caucasian adults. The current study confirmed the role of iPTH as one of the most sensitive biomarkers of vitamin D activity in vivo.

Prevalence, Characteristics, and Associated Risk Factors of Wrist Fractures in Americans Above 50: The Cross-Sectional NHANES Study

SUMMARY

By analyzing data from NHANES, we aimed to evaluate the prevalence, characteristics, and associated factors of wrist fractures in Americans aged 50 and above.

INTRODUCTION

Wrist fractures, whose prevalence increases with age, are one of the most common fractures in the United States. However, epidemiological studies on the prevalence of wrist fractures of certain ages were limited.

METHODS

The data of Americans aged 50 or above from 2013-2014 and 2017-2018 in NHANES were extracted and analyzed.

RESULTS

The prevalence of wrist fractures among Americans whose age was 50 or above was 12%, which was similar between men and women (men 12.8% vs. women 11.4%, p = 0.267). Among those who had experienced their first wrist fracture, 17.8% of the population experienced a second wrist fracture. The top two causes of the first wrist fracture were a fall from a standing height (56%) or a hard fall (34.8%). The prevalence of wrist fractures was higher in men than in women (13.7% versus 8.7%, p = 0.023) aged < 60, but higher in women than in men aged ≥ 60 (11.8% versus 14.3%, p = 0.007). Multivariate analysis showed that obesity, frequent drinking, current smoking, high serum phosphate level, non-Hispanic white women, and osteoporosis were independently associated with wrist fractures. Stratified by race, osteoporosis, frequent drinking, and high serum phosphate level were risk factors for wrist fractures in all races. As for Mexican Americans, non-Hispanic whites, and other races including multi-racial, current smoking was a risk factor of wrist factures. Furthermore, obesity was positively associated with wrist fractures in Mexican Americans, other Hispanics, and non-Hispanic whites.

CONCLUSION

The prevalence of wrist fractures in Americans aged 50 and above was 12%. Falling from a standing height was the main cause of the first wrist fracture. Frequent drinking, current smoker, high serum phosphate level, osteoporosis, obesity, and non-Hispanic women were more likely to experience wrist fractures.

Threshold for Relationship between Vitamin D and Parathyroid Hormone in Chinese Women of Childbearing Age

Background: The aim of this study was to assess the relationship between serum 25-hydroxyvitamin D [25(OH)D] and serum intact parathyroid hormone (PTH) in Chinese childbearing women, and to estimate the optimum threshold of 25(OH)D that maximally inhibits the PTH, which is considered to be the optimal status for vitamin D sufficiency. Methods: Serum samples were selected from the biological samples' bank of the Chinese Chronic Diseases and Nutrition Survey (CCDNS) 2015. The serum 25(OH)D concentration was determined by liquid chromatography tandem mass spectrometry and the serum PTH was determined by electronic chemiluminescence. Simple linear and partial correlation analysis, locally weighted regression smooth scatterplot (LOESS), nonlinear least squares estimation (NLS), and segmented regression (SR) were utilized to estimate the relationship of 25(OH)D and PTH, and to determine the threshold of 25(OH)D. Results: A total of 1568 serum samples of 25(OH)D concentration and PTH concentration were analyzed. A significant inverse relationship between 25(OH)D and PTH concentration was observed below 15.25 (14.22-16.28) ng/mL, and PTH decreased slowly with the increase of 25(OH)D above 16.75 (15.43-18.06) ng/mL after adjusting by age, latitude, city type, season, corrected calcium, and phosphorus. A very short plateau of PTH was found at 15.25 ng/mL and 16.75 ng/mL in terms of 25(OH)D according to LOESS, NLS, and SR. Conclusions: The serum 25(OH)D was negatively correlated with the serum PTH. The threshold of VitD sufficiency was found in the range of 14.22-18.06 ng/mL in terms of serum 25(OH)D concentration for Chinese childbearing women aged 18-44 years old.

Effect of vitamin D on cognitive decline: results from two ancillary studies of the VITAL randomized trial

Low vitamin D levels have been associated with cognitive decline; however, few randomized trials have been conducted. In a trial, we evaluated vitamin D3 supplementation on cognitive decline. We included participants aged 60+ years (mean[SD] = 70.9[5.8] years) free of cardiovascular disease and cancer in two substudies in the VITAL 2 × 2 randomized trial of vitamin D3 (2000 IU/day of cholecalciferol) and fish oil supplements: 3424 had cognitive assessments by phone (eight neuropsychologic tests; 2.8 years follow-up) and 794 had in-person assessments (nine tests; 2.0 years follow-up). The primary, pre-specified outcome was decline over two assessments in global composite score (average z-scores of all tests); substudy-specific results were meta-analyzed. The pooled mean difference in annual rate of decline (MD) for vitamin D3 versus placebo was 0.01 (95% CI - 0.01, 0.02; p = 0.39). We observed no interaction with baseline 25-hydroxyvitamin-D levels (p-interaction = 0.84) and a significant interaction with self-reported race (p-interaction = 0.01). Among Black participants (19%), those assigned vitamin D3 versus placebo had better cognitive maintenance (MD = 0.04, 95% CI 0.01, 0.08, similar to that observed for Black participants 1.2 years apart in age). Thus, vitamin D3 (2000 IU/day cholecalciferol) supplementation was not associated with cognitive decline over 2-3 years among community-dwelling older participants but may provide modest cognitive benefits in older Black adults, although these results need confirmation.Trial registration ClinicalTrials.gov; VITAL (NCT01169259), VITAL-DEP (NCT01696435) and VITAL-Cog (NCT01669915); the date the registration for the parent trial (NCT01169259) was submitted to the registry: 7/26/2010 and the date of first patient enrollment in either of the ancillary studies for cognitive function in a subset of eligible VITAL participants: 9/14/2011.

Clinical and biomarker modifiers of vitamin D treatment response: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Different 25-hydroxyvitamin D [25(OH)D] thresholds for treatment with vitamin D supplementation have been suggested and are derived almost exclusively from observational studies. Whether other characteristics, including race/ethnicity, BMI, and estimated glomerular filtration rate (eGFR), should also influence the threshold for treatment is unknown.

OBJECTIVES

The aim was to identify clinical and biomarker characteristics that modify the response to vitamin D supplementation.

METHODS

A total of 666 older adults in the Multi-Ethnic Study of Atherosclerosis (MESA) were randomly assigned to 16 wk of oral vitamin D3 (2000 IU/d; n = 499) or placebo (n = 167). Primary outcomes were changes in serum parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D [1,25(OH)2D] concentrations from baseline to 16 wk.

RESULTS

Among 666 participants randomly assigned (mean age: 72 y; 53% female; 66% racial/ethnic minority), 611 (92%) completed the study. The mean (SD) change in PTH was -3 (16) pg/mL with vitamin D3 compared with 2 (18) pg/mL with placebo (estimated mean difference: -5; 95% CI: -8, -2 pg/mL). Within the vitamin D3 group, lower baseline 25-hydroxyvitamin D [25(OH)D] was associated with a larger decline in PTH in a nonlinear fashion. With baseline 25(OH)D ≥30 ng/mL as the reference, 25(OH)D <20 ng/mL was associated with a larger decline in PTH with vitamin D3 supplementation (-10; 95% CI: -15, -6 pg/mL), whereas 25(OH)D of 20-30 ng/mL was not (-2; 95% CI: -6, 1 pg/mL). A segmented threshold model identified a baseline 25(OH)D concentration of 21 (95% CI: 13, 31) ng/mL as an inflection point for difference in change in PTH. Race/ethnicity, BMI, and eGFR did not modify vitamin D treatment response. There was no significant change in 1,25(OH)2D in either treatment group.

CONCLUSIONS

Of characteristics most commonly associated with vitamin D metabolism, only baseline 25(OH)D <20 ng/mL modified the PTH response to vitamin D supplementation, providing support from a clinical trial to use this threshold to define insufficiency. This trial was registered at clinicaltrials.gov as NCT02925195.

Low vitamin D in dark-skinned immigrants is mainly due to clothing habits and low UVR exposure: a Danish observational study

Low 25-hydroxyvitamin D₃ (25(OH)D) among dark-pigmented persons has been observed. To elucidate the reason for this we examined sun behaviour, sun-exposed body area, solar UVR exposure and 25(OH)D levels in immigrants with dark pigmented skin and Danes with light pigmented skin. Clothing, sun behaviour, and diet were recorded daily during a Danish summer season (93 analysed days). Erythema-weighted UVR doses were measured by personal electronic UVR dosimeters (with erythema response, measurement every 5th second) and 25(OH)D was measured in 72 participants (33 dark-skinned and 39 light-skinned). The immigrants exposed 28% less skin area, received 70% less UVR dose, and had 71% less 25(OH)D increase during the summer. The UVR reactivity (Δ25(OH)D per joule accumulated UVR dose) was similar (P = 0.62) among the immigrants (0.53 nmol l^-1 J^-1) and the Danes (0.63 nmol l^-1 J^-1). In the groups combined, 25(OH)D levels after summer were mainly influenced by UVR dose to exposed skin (28.8%) and 25(OH)D start level (27.9%). Height and measured constitutive skin pigmentation were of minor influence: 3.5% and 3.2%, respectively. Sun exposure and clothing habits were the main reasons for lower 25(OH)D level after summer in the darker immigrants, as both groups had similar UVR reactivity.

Population-based pediatric reference values for serum parathyroid hormone, vitamin D, calcium, and phosphate in Danish/North-European white children and adolescents

INTRODUCTION

Parathyroid hormone (PTH) and vitamin D are essential hormones in bone metabolism, especially during pediatric growth. Vitamin D insufficiency is often asymptomatic and is prevalent in high-latitude countries.

METHODS

In a Danish population-based cohort of 2211 6-18-year-olds, sex- and age-specific pediatric reference values for fasting concentrations of intact serum PTH, vitamin D (25-hydroxycholecalciferol, 25-OH-D), total calcium, and phosphate were generated in accordance with Clinical and Laboratory Standards Institute (CLSI) EP28-A3c guidelines. The effect of season on these biomarkers of bone metabolism was evaluated.

RESULTS

In boys, PTH concentrations increased with age, while the vitamin D and phosphate concentrations decreased (all p < .001). In girls, a peak in PTH concentrations and a nadir in vitamin D concentrations were observed in the 10-14-year-olds (both p < .001). Calcium and phosphate decreased with age for both sexes (girls: both p < .001; boys calcium: p < .05, boys phosphate: p < .001). Vitamin D was 20% lower in winter than summer for both sexes (both p < .001). Individuals with vitamin D sufficiency (25-OH-D > 50 nmol/L) exhibited a 5% lower level of PTH compared to the whole sample population (p < .001).

CONCLUSION

The concentrations of PTH, vitamin D, calcium, and phosphate vary during childhood and adolescence, and is dependent on sex and season. These factors should be considered when screening for and treating imbalances in bone metabolism.

Vitamin-D Binding Protein Gene Polymorphisms and Serum 25-Hydroxyvitamin-D in a Turkish Population

The rs7041 and rs4588 polymorphisms found in the GC gene, encoding vitamin D-binding protein (DBP), have distinct biochemical phenotypes. The aim of this study was to investigate vitamin D parameters with these polymorphisms, in individuals with possible vitamin D deficiency. The most common (49% of the cohort) genotype in rs7041 was GT, especially among individuals with high levels of free 25(OH)D calculated but with low levels of bioavailable 25(OH)D, and in rs4588 it was AC in particular among the individuals with low levels of bioavailable 25(OH)D. The most common phenotypes were Gc1s/2 (35.3%) and Gc1s/1s (31.4%), and Gc1f/1f was rare (5.9%). The variations in free and bioavailable 25(OH)D levels among healthy Turkish individuals may be attributed to the variations in total 25(OH)D as well as GC gene polymorphisms. The Turkish population shares a similarity for allele frequencies of rs7041 with the European population and similarity for allele frequencies of rs4588 with Gujarati Indians, and this may also be important in relation to certain ethnic populations showing associations between vitamin D and COVID-19.

The Relationship Between Intact Parathyroid Hormone and 25-Hydroxyvitamin D in United Kingdom Resident South Asians and Whites: A Comparative, Cross-Sectional Observational Study

Ethnic differences in intact parathyroid hormone (iPTH) at similar total 25 hydroxyvitamin D [25(OH)D] concentrations have been reported between US resident Whites, Blacks, and Hispanics, but this has not been studied between South Asians and Whites. We, therefore, compared the iPTH relationship to 25(OH)D in UK resident South Asians and Whites. A comparative, cross-sectional observational study in which demographic and laboratory data on South Asian and White residents of Wolverhampton, UK were analyzed. Log-log models measured the association between 25(OH)D and the interaction term of ethnicity and iPTH. Seven hundred and seventy-two patients consisting of 315 white subjects (208 women) and 457 South Asian subjects (331 women) were studied. Compared to South Asians, White subjects were older, had higher serum concentrations of 25(OH)D, creatinine (lower eGFR), adjusted calcium and magnesium, but similar concentrations of iPTH and phosphate. In an adjusted model, variables significantly associated with 25(OH)D included age, creatinine, adjusted calcium and ethnicity; but not iPTH and the interaction term of ethnicity and iPTH (beta coefficient -0.071, 95% CI -0.209, 0.067, p=0.32). In our study cohort, iPTH was not, per se, influenced by 25 (OH)D. We found no ethnic differences in the association between iPTH and 25(OH)D between South Asians and White UK residents.

Association of Serum Parathyroid Hormone Levels With All-Cause and Cause-Specific Mortality Among U.S. Adults

OBJECTIVE

To examine whether parathyroid hormone (PTH) is associated with mortality among U.S. adults.

METHODS

This study included 8286 U.S. adults aged ≥20 years with a measurement of serum intact PTH from the National Health and Nutrition Examination Survey 2003-2006 linked to national mortality data through 2015. Multivariable Cox proportional hazard regression models were employed to estimate the adjusted hazard ratio (aHR) of all-cause and cause-specific (cardiovascular and cancer) mortality according to intact PTH levels (low or low-normal, <38; middle-normal, 38-56; high-normal, 57-74; high, >74 pg/mL). We also stratified the analyses by serum albumin-adjusted calcium and 25-hydroxy vitamin D (25OHD) levels.

RESULTS

During a median follow-up of 10.1 years, the mean age was 49 years, and 48% were men. After adjusting for potential confounders, both the high-normal and high PTH groups showed higher risks of all-cause mortality than the low or low-normal PTH group (high-normal PTH, aHR, 1.28; 95% confidence interval [CI], 1.10-1.48; high PTH, aHR, 1.42; 95% CI, 1.19-1.69]. When stratified by calcium and 25OHD levels, the association between high PTH and mortality was also found among participants with albumin-adjusted calcium levels of ≥9.6 mg/dL (aHR, 1.53; 95% CI, 1.17-2.01) and those with 25OHD levels of ≥20 ng/mL (aHR, 1.46, 95% CI, 1.17-1.82). We found no evidence of the increased cause-specific mortality risks in the high PTH group.

CONCLUSION

Higher PTH levels were associated with an increased risk of all-cause mortality, particularly among participants with albumin-adjusted calcium levels of ≥9.6 mg/dL or 25OHD levels of ≥20 ng/mL.

Effect of serum 25-hydroxyvitamin D concentrations on skeletal mineralization in black and white women

INTRODUCTION

There is controversy over the adverse effect of vitamin D deficiency on bone mineralization. The purpose of this study was to determine the ethnical differences in vitamin D and bone mineralization as well as the association between vitamin D deficiency and bone mineralization defects.

MATERIALS AND METHODS

We examined serum 25-hydroxyvitamin D (25(OH)D) levels and transiliac bone biopsies in 92 healthy black and white women, aged 20-73 years. The major bone mineralization indices include osteoid volume per bone volume (OV/BV), osteoid surfaces per bone surface (OS/BS), osteoid thickness (O.Th) and mineralization lag time (Mlt).

RESULTS

25(OH)D levels were significantly lower and prevalence of 25(OH)D deficiency was significantly higher in blacks than in whites. However, none of the mineralization indices showed significant difference between the two groups. In addition, there was no significant correlation between 25(OH)D levels and mineralization indices in both black and white cohorts. Only one case had O.Th marginally greater than 12.5 µm, which is the cutoff value for identifying bone mineralization defects. OV/BV and OS/BS, but not O.Th, were significantly positively correlated with activation frequency (Ac.f).

CONCLUSIONS

Our study indicated: (1) vitamin D deficiency is common, but bone mineralization is not impaired in black women, and (2) there are no significant correlations between serum 25(OH)D levels and bone mineralization indices, suggesting that vitamin D deficiency may not be an independent factor contributing to bone mineralization defects and osteomalacia.

Association between Vitamin D and Risk of Stroke: A PRISMA-Compliant Systematic Review and Meta-Analysis

BACKGROUND

Previous studies have shown inconsistent results for associations between vitamin D and risk of stroke. We gathered the existing published articles and conducted this meta-analysis with the aim to explore the association between vitamin D and risk of stroke.

METHODS

We searched for articles exploring the association between vitamin D and risk of stroke and published before April 2021 in the following databases: PubMed, Web of Science, MEDLINE, EMBASE, and Google Scholar. All statistical analyses were made using STATA 12.0 software. Q test and I2 were applied to examine heterogeneities between studies.

RESULTS

For the association between serum levels of 25(OH) vitamin D and risks of stroke, the present analysis included 20 cohort studies (including 213,276 participants) and a case-control analysis (including 13,642 participants). Additionally, the analysis included 15 studies (including 41,146 participants given vitamin D supplementation and 41,163 participants given placebo) to evaluate the influence of vitamin D supplementation on risk of stroke. Higher circulating levels of 25(OH) vitamin D were associated with a reduced risk of stroke (odds ratio/relative risk = 0.78, 95% confidence interval [CI]: 0.70-0.86, I2 = 41.5%, p = 0.025). However, the present analysis showed that vitamin D supplementation did not influence the risk of stroke (hazard ratio = 1.05, 95% CI: 0.96-1.14, I2 = 2.3%, p = 0.425).

CONCLUSIONS

Our analysis indicated that lower circulating level of vitamin D was associated with an elevated risk of stroke, but extra supplement of vitamin D failed to show benefit in decreasing the risk of stroke. Further research and study are also needed to show the role of vitamin D in relation to stroke.