Consensus statement from 2nd International Conference on Controversies in Vitamin D

Vitamin D status in children undergoing allogeneic hematopoietic stem cell transplantation: A prospective exploratory study

OBJECTIVES

Allogeneic hematopoietic stem cell transplantation (HSCT) is associated with nutritional risks. This study describes vitamin D status and intake in children undergoing HSCT and compares results to healthy children.

METHODS

In a prospective observational study, vitamin 25(OH)D and 1,25(OH)2D were assessed at hospital admission before HSCT (baseline), at 3-month and 1-year post-transplant. Vitamin D deficiency was defined as 25(OH)D < 50 nmol/L. A 4-day diet record assessed vitamin D intake at 3-months and 1-year. Healthy children were assessed once.

RESULTS

Twenty-eight HSCT patients (mean age: 10.3-years, standard deviation [SD]: 4.0) and 50 healthy children (mean age: 10.0-years, SD: 3.6) were included. Vitamin D deficiency was more prevalent in patients at baseline (36%, p < 0.001) and 3-months (24%, p = 0.007) but not at 1-year (14%, p = 0.084) than in healthy children (2%). Median 1,25(OH)2D was significantly lower than in healthy children at the two first visits (p < 0.001) but not at 1-year (p = 0.198). Median vitamin D provision was higher at 3-months (18.1 µg/day) and 1-year (25 µg/day) compared to healthy children (5.3 µg/day, p < 0.001).

CONCLUSIONS

Children undergoing HSCT were at a high risk of vitamin D deficiency at baseline and 3-month post-transplant, but not at 1-year compared to healthy children. Vitamin D intake was higher after transplantation than in healthy children. These findings indicate that vitamin D requirements are elevated in HSCT patients, emphasizing the need for monitoring and adequate supplementation.

TRIAL REGISTRATION

Clinical Trials AEV2017/1. 2016/391/REK sør-øst B.

Vitamin D and hip protectors in osteosarcopenia: a combined hip fracture preventing approach

Osteosarcopenia is an emerging clinical condition highly prevalent in the older people. Affected subjects due to their intrinsic skeletal fragility and propensity to falls are at elevated risk of hip fractures which can increase morbidity and mortality. Strategies for attenuating the impact of predisposing factors on hip fractures are not yet well defined and should derive from multidisciplinary care and collaborations. Our aim was to narratively review available data on the preventive role of vitamin D and hip protectors on hip fractures in older patients with sarcopenia. Older subjects are at high risk of vitamin D deficiency and of falls due to several concomitant factors besides osteosarcopenia. Vitamin D protective actions against hip fractures may be mediated by both skeletal (increased mineralization) and extra-skeletal (reduced risk of falls) actions. Hip protectors may act downstream attenuating the effects of falls although their use is still not yet enough widespread due to the suboptimal compliance obtained by traditional hard devices. Concomitant use of vitamin D and hip protectors may represent an effective strategy in the prevention of hip fractures which need to be tested in ad hoc designed clinical trials.

Association of serum vitamin D level and live birth rate in women undergoing frozen embryo transfer-a retrospective cohort study

PURPOSE

To assess the association of serum vitamin D level and the live birth rate in women undergoing frozen embryo transfer (FET).

METHODS

This is a retrospective cohort study involving 1489 infertile women who had frozen embryo transfer at two tertiary reproductive medicine centres from 2019 to 2021. Only the first frozen embryo transfer was included for women who had repeated transfers during the period. Archived serum samples taken at LH surge or before the start of progestogens for FET were analysed for 25(OH)D levels using mass spectrometry. The main outcome measure was the live birth rate. Vitamin D deficiency was defined as serum 25(OH)D < 50 nmol/l (< 20 ng/ml) based on the Endocrine Society Clinical Practice guidelines.

RESULTS

The median age was 36 (25th-75th percentile 34-38) years. 37.7% (561/1489) women had cleavage stage embryo transfer and 62.3% (928/1489) women had blastocyst transfer. When analysing the results based on the threshold in the Endocrine Society guideline of 50 nmol/l (20 ng/ml) for vitamin D deficiency, there were no statistically significant differences in the live birth rate in the vitamin D deficient and non-deficient groups [151/489 (30.9%) vs 341/998 (34.2%), OR 0.861, 95% CI 0.683-1.086 P = 0.205]. There were no statistically significant differences in the pregnancy rates, ongoing pregnancy rates, and miscarriage rates between the two groups.

CONCLUSION

Serum vitamin D is not associated with birth rate in women undergoing FET.

Vitamin D status and intermediate vascular and bone outcomes in chronic kidney disease: a secondary post hoc analysis of IMPROVE-CKD

BACKGROUND AND AIMS

Cardiovascular disease is the leading cause of death in patients with chronic kidney disease (CKD) and has been associated with abnormalities of mineral metabolism and vascular calcification. Vitamin D influences parathyroid hormone values and calcium and phosphate metabolism, and may play a role in vascular function and bone health. We aimed to test our hypothesis that vitamin D deficiency is associated with arterial stiffness, aortic calcification and lower bone mineral density (BMD) in patients with CKD.

METHODS

A cross-sectional analysis was performed using baseline data from the IMpact of Phosphate Reduction On Vascular Endpoints in CKD (IMPROVE-CKD) study cohort. Clinical and laboratory parameters were compared between those with and without vitamin D deficiency, defined as 25-hydroxyvitamin D (25(OH)D) <50 nmol/L. Univariable and multivariable linear regression analyses were performed to assess associations between serum 25(OH)D levels and pulse wave velocity (PWV), augmentation index (AIx), abdominal aortic calcification (measured by the Agatston score) and lumbar spine BMD.

RESULTS

Baseline 25(OHD) values were available in 208 out of 278 IMPROVE-CKD study participants, with a mean value of 70.1 ± 30.7 nmol/L. Of these, 57 (27%) patients had vitamin D deficiency. Those with 25(OH)D deficiency were more likely to have diabetes (56% vs 38%), cardiovascular disease (54% vs 36%) and lower serum calcium (2.29 ± 0.13 vs 2.34 ± 0.13 mmol/L). On univariable and multivariable regression analyses, baseline 25(OH)D values were not associated with PWV, the AIx, Agatston score or BMD.

CONCLUSION

Baseline 25(OH)D levels were not associated with intermediate markers of vascular function and BMD in patients with CKD stages 3b and 4.

Vitamin D Controversies in the Laboratory Medicine: A Review of Clinical Guidelines and Recommendations

A narrative review of the main guidelines and recommendations published from 2011 up to date about the status of vitamin D deficiency has been carried out. The objective of this review is to discuss the origin of the controversy about the status of this entity, as well as the evolution of the methodological aspects and clinical situations that require vitamin D screening. The results obtained indicate that the criteria defining vitamin D status, according to two studies published in 2011, the Institute of Medicine (IOM) recommendations and the Endocrine Society (ES) guidelines, regardless the affected population. Concerning the methodology used, progress has been made thanks to the Vitamin D Standardization Program (VDSP), although the most recent results from the external Vitamin D External Quality Program Assessment Scheme (DEQAS) indicate that there is still a significant bias among the different immunoassays available. In relation to the criteria for screening, an agreement is observed in the most recent publications.

Vitamin D in pituitary driven osteopathies

The evidence that pituitary hormones may bypass peripheral endocrine glands to exert remarkable effects on the skeleton is gaining ground. Both hormonal excess and deficit may determine impairment in bone structure, and they commonly result in bone loss in patients affected by pituitary and neuroendocrine disorders. Vertebral fractures are the most common skeletal alterations and may occur independently of bone mass. Use of vitamin D (VD) supplementation is still debated in this setting. This review will focus on the interactions between different metabolites of VD and pituitary hormones, and the effects of VD supplementation on bone metabolism in patients with pituitary diseases.

Vitamin D Supplementation: Shedding Light on the Role of the Sunshine Vitamin in the Prevention and Management of Type 2 Diabetes and Its Complications

As the incidence of type 2 diabetes mellitus (T2DM) continues to increase globally, researchers are keen to investigate various interventions to mitigate its impact. Among these, vitamin D supplementation has attracted significant attention due to its influence on insulin secretion from the pancreas and insulin receptors in body cells. A substantial body of evidence indicates that vitamin D supplementation can reduce low-grade inflammation, a critical factor in developing insulin resistance. In addition, vitamin D aids in sustaining low resting concentrations of reactive oxygen species and free radicals, normalizes Ca2+ signaling, diminishes the expression of cytokines that are pro-inflammatory, and enhances the production of cytokines that are anti-inflammatory. This review discusses the effects of vitamin D on the glycemic control of individuals with T2DM and evaluates the impact of vitamin D supplementation on glycemic markers in this population. The investigation employs a comprehensive analysis of the existing literature with a special focus on recent studies published in the past decade. Based on the findings in the literature, it can be concluded that vitamin D supplementation alongside anti-diabetic medications may enhance glycemic control and potentially reduce the risk of diabetic complications. The evidence supports the notion that vitamin D supplementation can be a valuable addition to pharmacological agents for the management of T2DM, potentially enhancing glycemic control and overall health outcomes in affected individuals.

Vitamin D beyond the blood: Tissue distribution of vitamin D metabolites after supplementation

Vitamin D3's role in mineral homeostasis through its endocrine function, associated with the main circulating metabolite 25-hydroxyvitamin D3, is well characterized. However, the increasing recognition of vitamin D3's paracrine and autocrine functions-such as cell growth, immune function, and hormone regulation-necessitates examining vitamin D3 levels across different tissues post-supplementation. Hence, this review explores the biodistribution of vitamin D3 in blood and key tissues following oral supplementation in humans and animal models, highlighting the biologically active metabolite, 1,25-dihydroxyvitamin D3, and the primary clearance metabolite, 24,25-dihydroxyvitamin D3. While our findings indicate significant progress in understanding how circulating metabolite levels respond to supplementation, comprehensive insight into their tissue concentrations remains limited. The gap is particularly significant during pregnancy, a period of drastically increased vitamin D3 needs and metabolic alterations, where data remains sparse. Within the examined dosage ranges, both human and animal studies indicate that vitamin D3 and its metabolites are retained in tissues selectively. Notably, vitamin D3 concentrations in tissues show greater variability in response to administered doses. In contrast, its metabolites maintain a more consistent concentration range, albeit different among tissues, reflecting their tighter regulatory mechanisms following supplementation. These observations suggest that serum 25-hydroxyvitamin D3 levels may not adequately reflect vitamin D3 and its metabolite concentrations in different tissues. Therefore, future research should aim to generate robust human data on the tissue distribution of vitamin D3 and its principal metabolites post-supplementation. Relating this data to clinically appropriate exposure metrics will enhance our understanding of vitamin D3's cellular effects and guide refinement of clinical trial methodologies.

Vitamin D3 attenuates autoimmune thyroiditis by regulating Th17/Treg cell differentiation via YAP/JAK1/STAT1 axis

BACKGROUND

Autoimmune thyroiditis (AITD) is an organ-specific autoimmune disease. Substantial evidence suggests that Vitamin D (VitD) deficiency is closely associated with an increased risk of AITD. However, the effects of VitD3 on immune cells, especially Th17/Treg cell subsets, and the underlying molecular mechanism in AITD have not yet been investigated.

METHODS

An experimental autoimmune thyroiditis (EAT) mouse model was established with a high-iodine diet. After 8 weeks, thyroid injury was assessed using hematoxylin and eosin (H&E) staining. ELISA was employed to measure serum levels of thyroxine (T3 and T4), thyroid autoimmune antibodies (Tg-Ab and TPO-Ab), and inflammatory cytokines. Flow cytometry and multiplex fluorescence immunohistochemical (mIHC) assays were used to analyze Th17/Treg cell subsets. The CCK-8 and flow cytometry assays were used to determine cell viability and apoptosis.

RESULTS

Administration of VitD3 reduced thyroid follicle destruction, decreased lymphocyte infiltration, and lowered T3, T4, Tg-Ab, and TPO-Ab serum levels in EAT mice. VitD3 treatment also reduced the frequency of Th17 cells while promoting the Treg cell subset both in the thyroid tissue and in the splenocytes cultured in vitro. Furthermore, VitD3 administration suppressed the production of inflammatory cytokines in EAT mice. VitD3 was also found to regulate Treg cells' differentiation, viability, and apoptosis. Mechanistically, we discovered that VitD3 treatment upregulated YAP expression and activated the JAK/STAT pathway. Rescue assays confirmed that depletion of YAP counteracted the effects of VitD3 on Treg cell differentiation and function.

CONCLUSION

Vitamin D3 attenuates AITD by modulating Th17/Treg cell balance via regulating the YAP/JAK1/STAT1 axis.

Consensus Statement on Vitamin D Status Assessment and Supplementation: Whys, Whens, and Hows

The 6th International Conference, "Controversies in Vitamin D," was convened to discuss controversial topics, such as vitamin D metabolism, assessment, actions, and supplementation. Novel insights into vitamin D mechanisms of action suggest links with conditions that do not depend only on reduced solar exposure or diet intake and that can be detected with distinctive noncanonical vitamin D metabolites. Optimal 25-hydroxyvitamin D (25(OH)D) levels remain debated. Varying recommendations from different societies arise from evaluating different clinical or public health approaches. The lack of assay standardization also poses challenges in interpreting data from available studies, hindering rational data pooling and meta-analyses. Beyond the well-known skeletal features, interest in vitamin D's extraskeletal effects has led to clinical trials on cancer, cardiovascular risk, respiratory effects, autoimmune diseases, diabetes, and mortality. The initial negative results are likely due to enrollment of vitamin D-replete individuals. Subsequent post hoc analyses have suggested, nevertheless, potential benefits in reducing cancer incidence, autoimmune diseases, cardiovascular events, and diabetes. Oral administration of vitamin D is the preferred route. Parenteral administration is reserved for specific clinical situations. Cholecalciferol is favored due to safety and minimal monitoring requirements. Calcifediol may be used in certain conditions, while calcitriol should be limited to specific disorders in which the active metabolite is not readily produced in vivo. Further studies are needed to investigate vitamin D effects in relation to the different recommended 25(OH)D levels and the efficacy of the different supplementary formulations in achieving biochemical and clinical outcomes within the multifaced skeletal and extraskeletal potential effects of vitamin D.

Plasma Total Ascorbic Acid and Serum 25-Hydroxy-Vitamin-D Status in Patients with Venous Leg Ulcers: A Case-Control Study

Venous leg ulcers (VLUs) pose a significant burden on patients, health care systems, and national economies. Nutritional health is an important determinant of wound healing. Vitamin C and D levels and additional biochemical markers, C-reactive protein, and albumin in a group of patients with VLUs, were compared with a control group without VLUs. No significant difference in either nutrient marker was found with the presence, size, or duration of VLUs. Obesity was significantly more common in the VLU group, as noted in other studies. Additional controlled studies should be performed with measures of VLU size and duration to assess long-term outcomes with nutritional therapy.

25-hydroxyvitamin D and parathyroid hormone in new onset sepsis: A prospective study in critically ill patients

Hypovitaminosis D is highly prevalent in critically ill patients, and it has been suggested to be a risk factor for infections, sepsis and higher mortality. We sought to investigate whether serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) in critically ill patients with new onset sepsis are associated with severity and outcome. We prospectively included 50 consecutive critically ill adult cases with new onset sepsis and 50 healthy controls matched for age and sex. PTH and 25(OH)D were determined in serum via electrochemiluminescence immunoassays at inclusion in the study in all cases and controls, and one week after sepsis onset in cases. Patients had reduced 25(OH)D compared to controls at sepsis onset (7.9 ± 3 vs 24.6 ± 6.7 ng/mL, p < 0.001), whilst PTH was similar (median (range): 34.5 (5.7-218.5) vs 44.2 (14.2-98.1) pg/mL, p = 0.35). In patients, 25(OH)D upon enrollment and one week after did not differ significantly (7.9 ± 3 vs 7 ± 4.3 ng/mL, p = 0.19). All patients presented with hypovitaminosis D (25(OH)D < 20 ng/mL), while 40 patients (80 %) had vitamin D deficiency (25(OH)D < 12 ng/mL) at sepsis onset, including all ten (20 %) nonsurvivors, who died within 28 days from sepsis onset. Patients with sepsis (N = 28) and septic shock (N = 22) as well as survivors (N = 40) and nonsurvivors (N = 10) had similar 25(OH)D at enrollment (p > 0.05). 25(OH)D was positively correlated with ionized calcium (r = 0.46, p < 0.001) and negatively with PTH (p < 0.05), while inflammatory biomarkers or the severity scores exhibited no correlation with 25(OH)D. Patients with septic shock and nonsurvivors had lower PTH than patients with sepsis and survivors respectively (42.2 ± 42.9 vs 73.4 ± 61.9 pg/mL, p = 0.04, and 18.3 ± 10.7 vs 69.9 ± 58.8 pg/mL, p = 0.001, respectively). C-reactive protein was negatively associated with PTH (r = -0.44, p = 0.001). In conclusion, vitamin D deficiency was present in 80 % of critically ill patients at sepsis onset, while nonsurvivors exhibited lower PTH than survivors. Additional, larger and multicenter studies are warranted to elucidate the contribution of vitamin D and PTH to the pathogenesis of sepsis and its outcomes.

Correlation between serum vitamin D level and acute invasive enteritis in children

BACKGROUND

Diarrhea is a leading cause of death in young children worldwide. Vitamin D deficiency impairs the body's ability to clear pathogens, reduces tight junction protein expression in intestinal epithelial cells, and enhances Th1-mediated intestinal inflammation. This study aimed to investigate the effects of serum vitamin D levels on acute invasive enteritis in children.

METHODS

This prospective cohort study included 82 children aged 1-3 years with clinically diagnosed acute invasive enteritis at Sichuan Maternal and Child Health Hospital from February 2021 to February 2022, alongside a control group of 80 healthy children. Fecal specimens were collected for routine tests and occult blood analysis, while blood samples were taken for routine tests, C-reactive protein, and 25-OHD levels. Comparative analyses were performed between groups, and multifactorial logistic regression was used to identify factors influencing invasive enteritis.

RESULTS

The study group showed significantly lower serum 25-OHD levels (27.95 ± 9.91 ng/mL) compared to controls (32.76 ± 10.23 ng/mL, p < .01). Among the study group, 19.5% (16/82) had levels <20 ng/mL, versus 12.5% (10/80) in controls. Regular vitamin D supplementation was lower in the study group (58.5% vs. 77.5%, p < .05). Outdoor activity duration was also reduced (2.57 ± 0.98 h vs. 3.04 ± 0.88 h, p < .01). Multivariate analysis identified that exclusive breastfeeding, greater outdoor activity time and regular vitamin D supplementation were all associated with reduced risk of invasive enteritis (p < .05).

CONCLUSION

The findings indicate an association between low serum 25-OHD levels and acute invasive enteritis in children aged 1-3 years, suggesting that consistent vitamin D supplementation and sufficient outdoor activity may protect against this condition.

Effects of MTHFR C677T polymorphism on homocysteine and vitamin D in women with polycystic ovary syndrome

OBJECTIVES

To evaluate the correlation between serum vitamin D, homocysteine and the methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism in women with polycystic ovary syndrome (PCOS). Study design We retrospectively compared the serum homocysteine and vitamin D levels and the MTHFR C677T polymorphism in 104 PCOS patients and 104 controls. Parameters related to PCOS were statistically analysed.

RESULTS

Comparative analysis revealed that women with PCOS had significantly greater serum homocysteine levels (P = 0.002) and lower vitamin D concentrations (P = 0.040) than controls. The distribution frequency of the MTHFR C677T genotype did not significantly differ between the PCOS group and the control group. (P > 0.05). In the PCOS group, the serum level of homocysteine in the TT group was significantly greater than that in the CT (P = 0.003) and CC (P = 0.002) groups and the level of vitamin D in the TT group was significantly less than that in the CC (P < 0.001) and CT (P = 0.172) groups. The results were similar when the PCOS and control groups were divided according to whether they had insulin resistance. Vitamin D levels were significantly negatively correlated with homocysteine levels in all PCOS patients (r = -0.281, P = 0.004), similarly, vitamin D levels were negatively correlated with homocysteine levels in the CC, CT and TT of PCOS patients. According to multivariate analysis, vitamin D concentration was an independent risk factor for hyperhomocysteinaemia (adjusted OR 1.372, 95 % CI: 1.100-1.712).

CONCLUSIONS

No significant differences were found in the distributions of MTHFR C677T genotypes between the PCOS and control groups but these genotypes affected the patients' serum homocysteine and vitamin D concentrations. Women with the TT genotype have significantly lower vitamin D levels and higher homocysteine levels than women with the CC and CT genotypes. However, because of the limitations of this investigation, large-sample, high-quality prospective studies are needed to further verify these results in the future.

Serum vitamin D concentrations and sleep disorders: insights from NHANES 2011-2016 and Mendelian Randomization analysis

OBJECTIVE

This investigation seeks to examine the association between serum vitamin D concentrations and the prevalence of sleep disorders, additionally elucidating the causal relationship via Mendelian Randomization (MR) analysis.

MATERIALS AND METHODS

This research employed data from the National Health and Nutrition Examination Survey (NHANES) 2011-2016, focusing on adults aged 20-50 years reporting sleep disorders. The research encompassed 4913 American adults. Weighted multivariable logistic regression models and cubic spline analyses were utilized to evaluate the association between serum vitamin D concentrations and the incidence of sleep disorders. Additionally, a two-sample Mendelian Randomization analysis was performed to evaluate the potential causal link between serum vitamin D concentrations and the risk of sleep disorders.

RESULTS

Within the 2011-2016 NHANES cohort of the U.S. population, a notable inverse association was detected between serum vitamin D concentrations and sleep disorders (β =  - 3.81, 95% CI: - 6.10 to - 1.52, p = 0.003). After multivariate adjustments, a higher incidence of sleep disorders was associated with lower vitamin D Concentrations (OR 1.52, 95% CI 1.10-2.10, trend p = 0.014). Restricted cubic spline regression analysis indicated a linear association between serum vitamin D concentrations and sleep disorders(non-linearity p > 0.05). Lastly, the two-sample MR analysis yielded evidence supporting a potential causal connection between serum vitamin D concentrations and sleep disorders, with each unit increase in genetically predicted serum vitamin D reducing the odds ratio to 0.78 (95% CI 0.61-0.99, p = 0.044).

CONCLUSIONS

These results imply that lower vitamin D concentrations in the population might correlate with a heightened risk of sleep disorders, suggesting the importance of considering vitamin D supplementation when treating sleep disorders.

Associations between Longitudinal Maternal and Cord Blood Vitamin D Status and Child Growth Trajectories Up to 4 Years of Age

The current study aimed to explore the combined and individual effects of vitamin D (VitD) status in three trimesters during pregnancy and cord blood (CB) on child growth trajectories from birth to 4 years of age. Pregnant women (n = 1100) were recruited between 2013 and 2016 in the Shanghai Birth Cohort (SBC) Study. A total of 959 mother-child dyads were included. VitD status was measured by LC-MS/MS at three trimesters (T1, T2, T3) and CB. Children's weight, length/height, and head circumference were assessed at birth, 42 days, 6, 12, 24 months, and 4 years of age, and standardized into z-scores [weight-for-age z-score (WAZ), length-for-age z-score (LAZ), head circumference-for-age z-score (HCZ) and weight-for-length z-score (WLZ)]. Using the group-based trajectory model (GBTM), the trajectories of the four growth parameters were categorized into discrete groups. The generalized estimating equation (GEE) was employed to analyze the mixed effect of 25(OH)D throughout pregnancy on growth trajectories. The association between 25(OH)D status and each growth trajectory group was examined by multivariable logistic regression. Each 10 ng/mL increase in 25(OH) throughout three trimesters was not associated with four anthropometric parameters. Each 10 ng/mL increase in VitD in T3 was associated with a lower risk in the WAZ high-increasing trajectory (aOR: 0.75; 95% CI: 0.62, 0.91; p < 0.01). Each 10 ng/mL increase in VitD in CB was associated with a lower risk in the WAZ high-increasing trajectory (aOR: 0.57; 95% CI: 0.43, 0.76; p < 0.01). No significant association was found between maternal or CB VitD and LAZ or HCZ. Three trimesters' VitD throughout pregnancy had no persistent effect on the offspring's growth trajectory. However, higher VitD status in the third trimester and CB related to a lower risk of high-increasing WAZ from birth to 4 years of age. Elevated VitD levels in late pregnancy and cord blood may protect against continuous early-life weight growth at high levels.

Roles of THEM4 in the Akt pathway: a double-edged sword

The protein kinase B (Akt) pathway can regulate the growth, proliferation, and metabolism of tumor cells and stem cells through the activation of multiple downstream target genes, thus affecting the development and treatment of a range of diseases. Thioesterase superfamily member 4 (THEM4), a member of the thioesterase superfamily, is one of the Akt kinase-binding proteins. Some studies on the mechanism of cancers and other diseases have shown that THEM4 binds to Akt to regulate its phosphorylation. Initially, THEM4 was considered an endogenous inhibitor of Akt, which can inhibit the phosphorylation of Akt in diseases such as lung cancer, pancreatic cancer, and liver cancer, but subsequently, THEM4 was shown to promote the proliferation of tumor cells by positively regulating Akt activity in breast cancer and nasopharyngeal carcinoma, which contradicts previous findings. Considering these two distinct views, this review summarizes the important roles of THEM4 in the Akt pathway, focusing on THEM4 as an Akt-binding protein and its regulatory relationship with Akt phosphorylation in various diseases, especially cancer. This work provides a better understanding of the roles of THEM4 combined with Akt in the treatment of diseases.

Synergistic impact of 25-hydroxyvitamin D concentrations and physical activity on delaying aging

OBJECTIVE

Our study aims to examine the independent and combined associations of serum 25-hydroxyvitamin D [25(OH)D] concentrations and physical activity (PA) status with phenotypic age (PhenoAge).

METHOD

The analysis included 18,738 participants from the NHANES 2007-2010 & 2015-2018. Phenotypic Age Acceleration (PhenoAgeAccel) was calculated as the residuals from regressing PhenoAge on chronological age. Weighted multivariable logistic regression models were used to analysis the relationship between 25(OH)D and PA with PhenoAgeAccel. Population attributable fraction (PAF) was used to estimate the proportion of PhenoAgeAccel which could be avoided if exposure were eliminated.

RESULTS

The multivariate-adjusted OR (95%CI) for PhenoAgeAccel with high 25(OH)D and adequate PA were 0.657 (0.549,0.787) (p < 0.001) for all, 0.663 (0.538,0.818) (p < 0.001) for participants whose age ≤65years old. Furthermore, there was multiplicative interaction between 25(OH)D and PA in age ≤65 years old group (0.729 (0.542,0.979), p = 0.036). High 25(OH)D level and adequate PA reduced the risk of PhenoAgeAccel by 14.3 % and 14.2 %, respectively. Notably, 30.7 % decrease was attributable to both high 25(OH)D level and engaging in adequate PA concurrently. Combining 25(OH)D above 80.4 nmol/l with PA decreased PhenoAge by 1.291 years (p < 0.001).

CONCLUSION

Higher 25(OH)D level was associated with lower risk of biological ageing. Combining 25(OH)D and PA demonstrated enhanced protective effects, especially in middle or young adults. These findings underscore the importance of outdoor PA in slowing down the aging process.

Nutritional Behavior of Patients with Bone Diseases: A Cross-Sectional Study from Austria

BACKGROUND

A balanced diet rich in calcium and protein is recommended for bone-healthy people and osteoporosis patients, but it may also be important for rare bone disease (RBD). Little data is available on RBD and diet. Therefore, the aim of this study was to evaluate the nutritional behavior of patients with RBD.

METHODS

This single-center, cross-sectional, questionnaire-based study assessed the nutritional behavior of RBD patients (X-linked hypophosphatemia (XLH), osteogenesis imperfecta (OI), hypophosphatasia (HPP)), osteoporosis (OPO) patients and healthy controls (CTRL). The nutritional questionnaire comprised 25 questions from seven nutritional areas. The associations between socioeconomic factors and BMI were assessed by age-adjusted univariate analysis of covariance (ANCOVA).

RESULTS

Fifty patients with RBD (17 OI, 17 HPP, 16 XLH; mean age of 48.8 ± 15.9, 26.0% male, mean BMI 26.2 ± 5.6), 51 with OPO (mean age 66.6 ± 10.0, 9.8% male, mean BMI 24.2 ± 3.9) and 52 CTRL (mean age 50.8 ± 16.3, 26.9% male, mean BMI 26.4 ± 4.7) participated. Twenty-six (52.0%) RBD, 17 (33.4%) OPO and 24 (46.1%) CTRL were overweight or obese according to BMI. Only a minority of RBD, OPO and CTRL had a daily intake of at least three portions of milk or milk products (17.3% RBD, 15.6% OPO, 11.6% CTRL, p = 0.453). In general, similar nutritional behavior was observed between the three subgroups. However, significant differences were found in caffeine consumption (p = 0.016), fruit/vegetable juice consumption (p = 0.034), portions of fish per week (p = 0.044), high-fat meals per week (p = 0.015) and consumption of salty snacks (p = 0.001).

CONCLUSION

Nutritional counseling, controlling BMI and ensuring sufficient calcium and protein intake are crucial in patients with osteoporosis as well as in rare bone diseases. Vitamin D does not appear to be sufficiently supplied by the diet, and therefore supplementation should be considered in patients with bone diseases.

Nonlinear relationship between serum 25-hydroxyvitamin D and lipid profile in Chinese adults

Background

Previous studies on the liner associations between serum 25-hydroxyvitamin D [25(OH)D] levels and lipid profiles revealed ambiguous findings. The current study therefore tried to elucidate the possible non-linear associations between 25(OH)D and lipid profiles.

Methods

This study involved 8,516 adult participants (aged 18-74 years, males N = 3,750, females N = 4,766) recruited from the Dalian health management cohort (DHMC). The risk (OR) for specific dyslipidemias was estimated across the serum 25(OH)D levels and the cut-off value for serum 25(OH)D were determined by using logistic regression, restricted cubic spline, and piecewise linear regression methods, adjusted for age, sex, season, and ultraviolet index.

Results

In this study, a high prevalence of 25(OH)D deficiency was observed in the participants (65.05%). The level of 25(OH)D showed the inverse U-shaped correlations with the risks (ORs) of abnormal lipid profile, with inflection points observed at 23.7 ng/ml for hypercholesterolemia, 24.3 ng/ml for hypertriglyceridemia, 18.5 ng/ml for hyper-low-density lipoprotein cholesterolemia, 23.3 ng/ml for hypo-high-density lipoprotein cholesterolemia, 23.3 ng/ml for hyper-non-high-density lipoprotein cholesterol, and 24.3 ng/ml for high remnant cholesterol. The stratified analyses showed that the risk for most dyslipidemias related to deficiency of 25(OH)D was particularly increased among females aged 50-74 (except for hypertriglyceridemia, where the highest risk was among men aged 50-74 years), during winter/spring or under low/middle ultraviolet index environments.

Conclusions

Nonlinear inverse U-shaped associations were observed between 25(OH)D levels and abnormal lipid profile. The risk was particularly increased among females aged 50-74, during winter/spring period or under lower ultraviolet index environments. In vitamin D deficient subjects [25(OH)D <20 ng/ml], a positive association of serum vitamin D levels with the risk for dyslipidemia was observed, which needs a further.

Discordant Health Implications and Molecular Mechanisms of Vitamin D in Clinical and Preclinical Studies of Prostate Cancer: A Critical Appraisal of the Literature Data

Clinical and preclinical studies have provided conflicting data on the postulated beneficial effects of vitamin D in patients with prostate cancer. In this opinion piece, we discuss reasons for discrepancies between preclinical and clinical vitamin D studies. Different criteria have been used as evidence for the key roles of vitamin D. Clinical studies report integrative cancer outcome criteria such as incidence and mortality in relation to vitamin D status over time. In contrast, preclinical vitamin D studies report molecular and cellular changes resulting from treatment with the biologically active vitamin D metabolite, 1,25-dihydroxyvitamin D3 (calcitriol) in tissues. However, these reported changes in preclinical in vitro studies are often the result of treatment with biologically irrelevant high calcitriol concentrations. In typical experiments, the used calcitriol concentrations exceed the calcitriol concentrations in normal and malignant prostate tissue by 100 to 1000 times. This raises reasonable concerns regarding the postulated biological effects and mechanisms of these preclinical vitamin D approaches in relation to clinical relevance. This is not restricted to prostate cancer, as detailed data regarding the tissue-specific concentrations of vitamin D metabolites are currently lacking. The application of unnaturally high concentrations of calcitriol in preclinical studies appears to be a major reason why the results of preclinical in vitro studies hardly match up with outcomes of vitamin D-related clinical studies. Regarding future studies addressing these concerns, we suggest establishing reference ranges of tissue-specific vitamin D metabolites within various cancer entities, carrying out model studies on human cancer cells and patient-derived organoids with biologically relevant calcitriol concentrations, and lastly improving the design of vitamin D clinical trials where results from preclinical studies guide the protocols and endpoints within these trials.

The effect of vitamin D2 supplementation on vitamin D levels in humans: A time and dose-response meta-analysis of randomized controlled trials

BACKGROUND

Inconsistencies exist regarding the influence of vitamin D2 (ergocalciferol) supplementation on serum vitamin D levels. These inconsistencies could be attributed to numerous factors, such as dosage, baseline vitamin D levels, and duration of intervention. Hence, this dose-response meta-analysis of randomized controlled trials was conducted to assess the efficacy of vitamin D2 supplementation on vitamin D levels.

METHODS

Relevant studies were searched in PubMed/Medline, Web of Science, Embase, and Scopus, from their inception to 3 January 2023. Variable alterations were considered to calculate the pooled weighted mean difference (WMD) with 95% confidence interval (CI) using the random effects model.

RESULTS

Pooled results from 33 study arms demonstrated that Vitamin D2 treatment significantly increases total vitamin D concentrations (WMD: 11.47 ng/mL, 95 %CI: 9.29 to 13.64, p < 0.001), 25(OH)D2 concentrations (WMD: 11.40 ng/mL, 95 %CI: 4.72 to 18.09, p = 0.001), and 1,25(OH)D concentrations (WMD: 5.61 ng/mL, 95 %CI: 0.74 to 10.48, p = 0.024), but decreases 25(OH)D3 concentrations (WMD: -4.63 ng/mL, 95 %CI: -6.46 to -2.81, p < 0.001). In subgroup analyses, increase in total vitamin D concentrations was more significant in vitamin D2 doses >2000 IU/day (WMD: 13.82 ng/mL), studies with duration ≤12 weeks (WMD: 12.53 ng/mL), participants aged ≥60 years (WMD: 14.40 ng/mL), and trials with basal 25(OH)D concentrations <20 ng/mL (WMD: 11.47 ng/mL).

CONCLUSIONS

This meta-analysis indicates that the supplementation of vitamin D2 significantly increases the serum concentrations of total vitamin D, 25(OH)D2, and 1,25(OH)D, but decreases 25(OH)D3 concentrations. Careful consideration of patient characteristics, dosage, and treatment duration is recommended for vitamin D2 supplementation.

Association of serum 25-hydroxy-vitamin D concentration and risk of mortality in cancer survivors in the United States

PURPOSE

Cancer survivors have a high risk of mortality, and vitamin D (VD) is associated with the risk of mortality. This study is aim to examine the impact of VD on mortality in cancer survivors.

METHODS

A prospective study was conducted using data from the National Health and Nutrition Examination Survey. Participants were obtained information on their baseline characteristics, dietary habits, comorbidities, lifestyle, and serum 25-hydroxy VD [25(OH)D] concentrations. The weighted Cox proportional hazard and competing risk regression models were used to estimate the hazard ratio and 95% confidence intervals (HR, 95% CI) of mortality for different serum 25(OH)D concentrations. Restricted cubic spline (RCS) curves were utilized to illustrate the dose-response relationship between serum 25(OH)D concentrations and mortality.

RESULTS

The study encompassed 2,495 participants with cancer diagnoses. Multivariate models indicated that, compared to serum 25(OH)D concentrations below 58.5 nmol/L, concentrations exceeding 81.6 nmol/L were associated with reduced HRs for all-cause mortality (HR = 0.70; 95% CI: 0.56-0.87), cardiovascular mortality (HR = 0.53; 95% CI: 0.32-0.86), and cancer-specific mortality (HR = 0.66; 95% CI: 0.45-0.99). RCS curves revealed "L-shaped" associations between serum 25(OH)D concentration and both all-cause and cancer-specific mortality, with threshold effects at 87.9 nmol/L and 84.6 nmol/L, respectively. Conversely, the relationship between serum 25(OH)D concentration and cardiovascular mortality exhibited a more linear pattern, with a threshold at 88.7 nmol/L. Subgroup analyses highlighted a gender-specific interaction that elevated serum 25(OH)D concentrations were significantly more protective against mortality in males than in females, especially regarding cancer-specific mortality (P-interaction = 0.009).

CONCLUSION

Elevated serum 25(OH)D concentrations were correlated with decreased risks of all-cause, cardiovascular, and cancer-specific mortality in cancer survivors, with benefit thresholds at 87.9, 88.7, and 84.6 nmol/L, respectively. These findings suggested that cancer survivors might benefit from higher vitamin D recommendations than the general population.

An AuNPs-based electrochemical aptasensor for the detection of 25-hydroxy vitamin D3

Vitamin D3 (VD3) is the main form of vitamin D and an essential nutrient for maintaining human life. Currently, traditional methods for detecting 25-hydroxyvitamin D3(25(OH)D3) are complex and expensive. In this study, we constructed an accurate, sensitive, simple, and cost-effective label-free biosensor based on an aptamer for the detection of 25(OH)D3. The aptamer-modified sulfhydryl adopted self-assembly as a way to stably immobilize at the glassy carbon electrode (GCE) surface modified by gold nanoparticles (AuNPs). Upon 25(OH)D3 binding to the aptamer, the complexes inhibit electron transfer at the electrode surface, leading to reduced [Fe(CN)6]3-/4- redox peak current. Consequently, the quantity of 25(OH)D3 that interacts with the electrode-bound aptamer correlates with the observed electric current response values. The Aptamer/AuNPs/GCE aptasensor achieved direct and highly sensitive detection of 25(OH)D3 over a wide concentration range (1.0-1000 nM), with a limit of detection of 1.0 nM. At the same time, other molecules with a similar structure, such as 25(OH)D2, Vitamin D3, and Vitamin D2, had lower response interference than 25(OH)D3. Therefore, this biosensor has great potential to become a portable diagnostic device for 25(OH)D3.

Proportion of vitamin D deficiency in children/adolescents with type 1 diabetes: a systematic review and meta-analysis

BACKGROUND

The impact of vitamin D on type 1 diabetes has been a controversial topic in public health. Furthermore, significant differences in the proportion of vitamin D have been noted. The purpose of this systematic review was to determine the overall proportion of vitamin D deficiency in children/adolescents with type 1 diabetes (T1D).

METHODS

Based on six electronic databases (PubMed, Web of Science, Embase, Ovid Medline, ProQuest, and Cochrane Library), eligible studies since the databases' inception up to April 2022 were searched. Reference lists were also manually searched to identify additional studies. Overall, studies with statistical information on vitamin D deficiency in children and adolescents with T1D were included, and a random effects model was applied for the meta-analysis. In addition, subgroup and sensitivity analyses were carried out to evaluate heterogeneity, and publication bias was evaluated by using Egger's test.

RESULTS

A total of 45 studies involving 6,995 participants met the inclusion criteria; these included 25 countries covering Africa, Oceania, Europe, North America and Asia. The proportion of vitamin D deficiency in children/adolescents with T1D was 45% (95% confidence interval [CI] 37-54%, I2 = 97.94%). Subgroup analysis further revealed that the publication year, study design, vitamin D classification, season and geographical region significantly contributed to the variation in the reported incidence of vitamin D deficiency.

CONCLUSIONS

The results of the meta-analysis showed that the proportion of vitamin D deficiency among T1D children/adolescents was 45%. In addition, the proportion remains higher, which has important implications for adapting health and social care systems.

Should I Supplement Vitamin D in a Patient With Sepsis?

Sepsis is a potentially fatal organ failure produced by the host's immune response to infection. It is critical to identify risk factors associated with a poor prognosis in septic patients in order to develop new therapy options. Vitamin D deficiency (25-hydroxyvitamin cholecalciferol < 20 ng/mL) is common in critical and septic patients. Serum vitamin D concentrations are associated with an increased incidence of mortality in critically ill adult patients. In critically ill patients, vitamin D supplementation (a very high vitamin D 3 or cholecalciferol loading dosage as a single bolus dose ranging from 400,000 to 540,000 IU) is feasible and safe. Some of the trials and their post-hoc analyses evaluating vitamin D supplementation in severely sick individuals, including septic patients, suggested possible benefits in mortality (reduced 28-day mortality in the range of 8.1%-17.5%), and other outcomes (reduction in hospital length in the range from 9 to 18 days, and decrease in duration of mechanical ventilation in the range from 5 to 10 days). Despite the fact that many studies support the provision of vitamin D to septic patients, there are still many studies that contradict this opinion, and there is still debate about the recommendation to use vitamin D in sepsis. A pragmatic clinical approach in severe sepsis could be supplementation of vitamin D if serum levels are diminished (< 30 ng/mL). It appears that a single ultrahigh dose of vitamin D 3 (cholecalciferol) could be administered to the septic patient via an enteral tube, followed by daily or monthly maintenance doses. Parenteral administration might be reserved for a subgroup of septic patients with gastrointestinal, hepatic, or renal dysfunction. Future clinical trials designed exclusively for septic patients are required to assess the potential advantages of vitamin D. Possible impacts of selective activators of vitamin D receptors, such as paricalcitol, should be elucidated in sepsis. This emphasizes the requirement for more study and confirmation of any potential beneficial effects of vitamin D in sepsis.

Vitamin D and cancer

The role of vitamin D in the prevention of chronic diseases including cancer, has received a great deal of attention during the past few decades. The term "Cancer" represents multiple disease states with varying biological complexities. The strongest link between vitamin D and cancer is provided by ecological and studies like observational, in preclinical models. It is apparent that vitamin D exerts diverse biological responses in a tissue specific manner. Moreover, several human factors could affect bioactivity of vitamin D. The mechanism(s) underlying vitamin D initiated anti-carcinogenic effects are diverse and includes changes at the muti-system levels. The oncogenic environment could easily corrupt the traditional role of vitamin D or could ensure resistance to vitamin D mediated responses. Several researchers have identified gaps in our knowledge pertaining to the role of vitamin D in cancer. Further areas are identified to solidify the role of vitamin D in cancer control strategies.

Features of d-vitamin status in young children in the Kazakh population

OBJECTIVE

Aim: The purpose of the article is to form the parameters of vitamin D status in young children in the ethnic group of Kazakh nationality with the factor of highlighting the necessary recommendations for the prevention of hypovitaminosis D.

PATIENTS AND METHODS

Materials and Methods: Methods for the study of the highlighted problem are the diagnosis of young children in the parameter of clinical and anamnestic research, which includes the collection of anamnestic data of children of Kazakh nationality within the framework of the identified data based on a questionnaire of parents, an evaluation component in the child's health factor at the level of his initial state, and laboratory analysis to determine 25(OH)D to identify the content of vitamin D using the method of electrochemiluminescent immunoassay.

RESULTS

Results: Analysis of vitamin D levels revealed significant differences among age groups. In the 0-28-day group, average vitamin D was 13.35 ng/ml, with 92.8% deficient. In the 1-6-month group, it was 21.47 ng/ml, with 84% deficient. In the over 6-month group, it was 33.58 ng/ml, with 40% sufficient. Formula-fed children had the lowest levels (average 15.21 ng/ml), while breastfed children had insufficiency (average 23.91 ng/ml). Children with vitamin D supplementation averaged 25.9 ng/ml, compared to 19.01 ng/ml without supplementation.

CONCLUSION

Conclusions: The results point to a widespread deficiency of vitamin D and offer practical recommendations for its prevention, such as creating a unified system of timely diagnosis, implementing preventive measures in pregnant women and young children, including a balanced diet enriched with vitamin D, staying outdoors in the bright hours of the day.

Vitamin D insufficiency and disease risk in the elderly

Vitamin D insufficiency, milder than deficiency, is common, and a risk of various diseases. Since vitamin D exert diverse actions, both skeletal and non-skeletal, its insufficiency is a risk of various diseases including osteoporosis, sarcopenia, cardiovascular disease, cancer, and even mortality. Regarding the association of vitamin D status and disease risk, a marked discrepancy exists between the results from the observational studies and intervention studies, mostly yielding the positive and negative results in the former and latter, respectively. Such inconsistency probably arises from methodological problems, of which the baseline vitamin D status would be the most important. Vitamin D intervention would be effective in the deficient/insufficient subjects, but not in sufficient subjects. Since the elderly subjects, especially the institutionalized people, are mostly vitamin D deficient/insufficient, they are likely to benefit from improvement of vitamin D status. Vitamin insufficiency is a risk of various diseases, and correcting the vitamin status alone would reduce the risk of many diseases, and favorable to avoid the undesirable consequences of polypharmacy in the elderly. Additionally, disease prevention by nutritional improvement is cheap and free from side effects, and suited for the primary prevention of diseases.

Intense Testing and Use of Vitamin D Supplements Leads to Slow Improvement in Vitamin D Adequacy Rates: A Cross-Sectional Analysis of Real-World Data

BACKGROUND

Vitamin D testing (VDT) and supplement use (VDS) are on the rise, but most patients remain deficient (<30 ng/mL-VDD). We designed the present real-world study to assess this paradox.

METHODS

We reviewed data from all patients visiting our clinics between 2014 and 2022. We estimated the rate of patients with vitamin D adequacy (≥30 ng/mL) (VDA) by year and month of testing, the dose of VDS (low (≤1200 IU/day), medium (1201-3000 I/day) and high dose (>3000 IU/day)), intake duration (short-term (<12 months) and long-term use (≥12 months)), and timing of use (current use, former use, no use).

RESULTS

We enrolled n = 6912 subjects with vitamin D measurements: n = 5195 females (75.2%), age 44.0 ± 16.8 years, BMI 27.9 ± 6.5 kg/m2; never users: n = 5553 (80.3%), former users: n = 533 (7.7%), current users: n = 826 (12.0%). Current use of VDS was higher in females. VDT rose from 42.1% in 2014 to 92.7% in 2022, and VDA rose from 14.8% to 25.5% for the same time. VDA was found overall in n = 1511 (21.9%); Never users: n = 864 (15.6%), Former users: n = 123 (23.2%); and Current users: n = 370 (44.8%). The maximal VDA (67.9%) was found in subjects using high-dose VDS in the long term.

CONCLUSIONS

Despite the significant rise in VDT and VDS use, VDA was found in a minority of patients. Prolonged use of high-dose supplements produces modest improvements in VDA.

Cholecalciferol Use Is Associated With a Decreased Risk of Incident Morphometric Vertebral Fractures in Acromegaly

CONTEXT

Skeletal fragility is observed in 30% to 60% of acromegaly patients, representing an emerging complication of the disease that increases disability. Despite several studies having investigated the clinical and hormonal prognostic factors for the occurrence of vertebral fractures (VFs) in acromegaly, very few data are available on their prevention/treatment including the effect of vitamin D (VD) supplementation, which has been reported to have a fracture-protective effect in several studies in patients with osteoporosis.

OBJECTIVE

We aimed to investigate the role of cholecalciferol (D3) supplementation in the prevention of incident VFs (i-VFs) in acromegaly.

METHODS

A longitudinal, retrospective and multicenter study was performed on 61 acromegaly patients treated and untreated with D3 supplementation.

RESULTS

Twenty-six patients were treated with D3 supplementation according to clinical guidelines. The median D3 weekly dosage was 8500 IU (interquartile range [IQR]: 3900). The median duration of D3 supplementation was 94 months (IQR: 38). At last follow-up, i-VFs were diagnosed in 14 patients (23%). I-VFs were less prevalent in patients on D3 supplementation (14.3% of cases) compared to patients not treated with D3 (85.7%; P = .02). The final level of serum V25OH-D was significantly lower in patients who developed i-VFs (28.6 ng/mL, IQR: 4.1) compared to patients who did not develop i-VFs (34.2 ng/mL, IQR: 9.6; P = .05). The logistic regression confirmed the protective role of D3 supplementation on the occurrence of i-VFs (odds ratio: 0.16; 95% CI, 0.03-0.79; P = .01).

CONCLUSION

It is likely that D3 supplementation could lead to a reduction in i-VFs in acromegaly.

Vitamin D deficiency in adulthood: Presentation of 2familial cases simulating pseudohypoparathyroidism

BACKGROUND AND OBJECTIVE

The clinical and biochemical overlap of various pathologies of phosphocalcic metabolism can lead to misdiagnosis and consequent clinical management. One example is pseudohypoparathyroidism, which can be confused with vitamin D-dependent rickets (VDDR1) if appropriate biochemical determinations are not performed.

PATIENTS AND METHODS

Two pairs of siblings, from independent families, were clinically diagnosed in adolescence with pseudohypoparathyroidism due to hypocalcaemia, elevated parathyroid hormone levels and normal or elevated phosphorus values. After ruling out alterations in GNAS, a massive sequencing study of genes associated with other differential diagnoses was carried out.

RESULTS

Two genetic variants in the CYP27B1 gene potentially associated with the phenotype were identified. Pathogenic variants in this gene are associated with VDDR1A. Clinical-biochemical re-evaluation of the patients confirmed this diagnosis and treatment was adapted.

CONCLUSIONS

Although VDDR1A is an infrequently diagnosed pathology in adulthood, in cases of hypocalcaemia with elevated PTH values, determination of the 1,25(OH)2D3 and 25(OH)D3 forms of vitamin D is relevant to reach a correct diagnosis.

Association between the serum vitamin D level and prevalence of obesity/abdominal obesity in women with infertility: a cross-sectional study of the National Health and Nutrition Examination Survey data

AIMS

To explore the relationship between vitamin D and obesity and abdominal obesity in women with infertility.

MATERIAL AND METHODS

We screened the data from National Health and Nutrition Examination Survey (NHANES) 2013-2016. A total of 201 infertile women between the ages of 20 and 40 years were included in our study. To estimate the independent association of vitamin D with obesity and abdominal obesity, we used weighted multivariate logistic regression models and cubic spline analyses.

RESULTS

Among infertile women in the NHANES 2013-2016 database, serum vitamin D levels were significantly and negatively associated with body mass index (ß= -0.96, 95% CI: -1.40, -0.51, p < 0.001)and waist circumference (ß= -0.40, 95% CI: -0.59, -0.22, p < 0.001), respectively. After multivariable adjustment, lower vitamin D levels were found to be associated with a higher prevalence of obesity (OR: 8.290, 95% CI: 2.451-28.039, p for trend = 0.001) and abdominal obesity (OR: 4.820, 95%CI: 1.351-17.194, p for trend =0.037). Spline regression showed linearity of the associations between vitamin D and obesity/abdominal obesity (p for nonlinearity > 0.05).

CONCLUSION

Our findings suggested that a decreased vitamin D might correspond to a higher prevalence of obesity in infertile women, which reminded us to pay more attention to the supplement of vitamin D in obese infertile women.

Acromegaly and Bone: An Update

Since our discovery in 2006 that acromegaly is associated with an increased risk of vertebral fractures, many authors have confirmed this finding in both cross-sectional and prospective studies. Due to the high epidemiological and clinical impact of this newly discovered comorbidity of acromegaly, this topic has progressively become more important and prominent over the years, and the pertinent literature has been enriched by new findings on the pathophysiology and treatment. The aim of this narrative review was to discuss these novel findings, integrating them with the seminal observations, in order to give the reader an updated view of how the field of acromegaly and bone is developing, from strong clinical observations to a mechanistic understanding and possible prevention and treatment.

Vitamin D and depression in older adults: lessons learned from observational and clinical studies

Depression is a mental disorder triggered by the interaction of social, psychological and biological factors that have an important impact on an individual's life. Despite being a well-studied disease with several established forms of treatment, its prevalence is increasing, especially among older adults. New forms of treatment and prevention are encouraged, and some researchers have been discussing the effects of vitamin D (VitD) on depression; however, the exact mechanism by which VitD exerts its effects is not yet conclusive. In this study, we aimed to discuss the possible mechanisms underlying the association between VitD and depression in older adults. Therefore, we conducted a systematic search of databases for indexed articles published until 30 April 2021. The primary focus was on both observational studies documenting the association between VitD and depression/depressive symptoms, and clinical trials documenting the effects of VitD supplementation on depression/depressive symptoms, especially in older adults. Based on pre-clinical, clinical and observational studies, it is suggested that the maintenance of adequate VitD concentrations is an important issue, especially in older adults, which are a risk population for both VitD deficiency and depression. Nevertheless, it is necessary to carry out more studies using longitudinal approaches in low- and middle-income countries to develop a strong source of evidence to formulate guidelines and interventions.

Vitamin D status and supplementation before and after Bariatric Surgery: Recommendations based on a systematic review and meta-analysis

Bariatric surgery is associated with a postoperative reduction of 25(OH) vitamin D levels (25(OH)D) and with skeletal complications. Currently, guidelines for 25(OH)D assessment and vitamin D supplementation in bariatric patients, pre- and post-surgery, are still lacking. The aim of this work is to analyse systematically the published experience on 25(OH)D status and vitamin D supplementation, pre- and post-surgery, and to propose, on this basis, recommendations for management. Preoperatively, 18 studies including 2,869 patients were evaluated. Prevalence of vitamin D insufficiency as defined by 25(OH)D < 30 ng/mL (75 nmol/L) was 85%, whereas when defined by 25(OH)D < 20 ng/mL (50 nmol/L) was 57%. The median preoperative 25(OH)D level was 19.75 ng/mL. After surgery, 39 studies including 5,296 patients were analysed and among those undergoing either malabsorptive or restrictive procedures, a lower rate of vitamin D insufficiency and higher 25(OH)D levels postoperatively were observed in patients treated with high-dose oral vitamin D supplementation, defined as ≥ 2,000 IU/daily (mostly D3-formulation), compared with low-doses (< 2,000 IU/daily). Our recommendations based on this systematic review and meta-analysis should help clinical practice in the assessment and management of vitamin D status before and after bariatric surgery. Assessment of vitamin D should be performed pre- and postoperatively in all patients undergoing bariatric surgery. Regardless of the type of procedure, high-dose supplementation is recommended in patients after bariatric surgery.

Automated LC-MS/MS: Ready for the clinical routine Laboratory?

Background

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a sensitive method with high specificity. However, its routine use in the clinical laboratory is hampered by its high complexity and lack of automation. Studies demonstrate excellent analytical performance using the first fully automated LC-MS/MS for 25-hydroxy vitamin D and immunosuppressant drugs (ISD) in hospital routine laboratories.

Objectives

Our objectives were (1) to verify the suitability of an automated LC-MS/MS in a commercial laboratory, which differs from the needs of hospital laboratories, and (2) examine its usability among operators with various professional backgrounds.

Methods

We assessed the analytical assay performance for vitamin D and the ISDs cyclosporine A and tacrolimus over five months. The assays were compared to an identical analyzer in a hospital laboratory, to in-house LC-MS/MS methods, and to chemiluminescent microparticle immunoassays (CMIA). Nine operators evaluated the usability of the fully automated LC-MS/MS system by means of a structured questionnaire.

Results

The automated system exhibited a high precision (CV < 8%), accuracy (bias < 7%) and good agreement with concentrations of external quality assessment (EQA) samples. Comparable results were obtained with an identical analyzer in a hospital routine laboratory. Acceptable median deviations of results versus an in-house LC-MS/MS were observed for 25-OH vitamin D3 (-10.6%), cyclosporine A (-4.3%) and tacrolimus (-6.6%). The median bias between the automated system and immunoassays was only acceptable for 25-OH vitamin D3 (6.6%). All users stated that they had had a good experience with the fully automated LC-MS/MS system.

Conclusions

A fully automated LC-MS/MS can be easily integrated for routine diagnostics in a commercial laboratory.

Vitamin D and cathelicidin levels and susceptibility to Mycobacterium tuberculosis infection acquisition in household contacts

INTRODUCTION

Vitamin D deficiency has been proposed to confer susceptibility to acquiring tuberculosis infection by impairing the innate immune response.

METHODS

In an exploratory study, we examined whether the levels of 25-hydroxyvitamin D3 (25(OH)D3) in serum, and cathelicidin - an antimicrobial peptide-induced under calcitriol - in the nasal fluid, would associate with the risk of acquiring tuberculosis infection.

RESULTS

Within a prospective cohort of 231 tuberculosis household contacts tested with repeated interferon-gamma release assays, we serially analyzed all the uninfected contacts acquiring tuberculosis infection at follow-up ("converters", n=18), and an age and sex-matched control group of contacts not acquiring tuberculosis infection ("non-converters", n=36). The median levels of serum 25(OH)D3 did not differ between convertors and non-converters at baseline (14.9 vs. 13.2 ng/ml, p=0.41), nor at follow-up (19.0 vs 18.6ng/ml, p=0.83). Similarly, cathelicidin levels did not differ between both groups.

CONCLUSION

These data argue against a major role for hypovitaminosis D in tuberculosis infection susceptibility.

Decreased vitamin D levels in obsessive-compulsive disorder patients

OBJECTIVE

The present paper compared vitamin D levels in adult patients with obsessive-compulsive disorder (OCD) and explored possible correlations with patients' characteristics.

METHODS

Fifty outpatients with OCD, according to DSM-5 criteria, were included and assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the Hamilton Rating Scale for Depression (HRDS).

RESULTS

All the patients except one showed lower vitamin D levels than normative values (>30 nm/L). Vitamin D values of the whole sample were negatively correlated with Y-BOCS total, compulsion subscale, and some items' scores, specifically "interference from obsessions," "distress associated with obsessions," and "time spent on compulsions". The same relationships were detected in men, while women showed negative correlations between vitamin D levels and Y-BOCS compulsion subscale and "resistance to compulsions," "degree of control of compulsions," "insight" item scores.

CONCLUSIONS

Our findings would indicate that vitamin D might be involved in the pathophysiology of OCD, and that it is possibly related to the severity of the disorder and to typical symptoms, with some sex-related peculiarities. Further studies are necessary to support or not our findings and to ascertain the effectiveness of vitamin D supplementation in patients with OCD.

Low Vitamin D Levels Are Associated With Long COVID Syndrome in COVID-19 Survivors

CONTEXT

Long COVID is an emerging syndrome affecting 50% to 70% of COVID-19 survivors that still lacks predicting factors.

OBJECTIVE

Due to the extraskeletal effects of vitamin D, we retrospectively assessed the association between 25(OH) vitamin D levels and long COVID in COVID-19 survivors 6 months after hospitalization.

METHODS

Long COVID was defined according to NICE guidelines. Fifty long COVID and 50 non-long-COVID subjects matched on a 1:1 basis were enrolled from an outpatient clinic post-COVID cohort seen from August to November 2020. Therapies/comorbidities affecting calcium/vitamin D/bone metabolism, and/or admission to the intensive care unit during hospitalization were exclusion criteria. 25(OH) Vitamin D was measured at hospital admission and 6 months after discharge.

RESULTS

We observed lower 25(OH) vitamin D levels, evaluated at follow-up, in subjects with long COVID than those without (20.1 vs 23.2 ng/mL, P = .03). Regarding the affected health areas evaluated in the entire cohort, we observed lower 25(OH) vitamin D levels in those with neurocognitive symptoms at follow-up (n = 7) than those without (n = 93) (14.6 vs 20.6 ng/mL, P = .042). In patients presenting vitamin D deficiency (<20 ng/mL), both at admission and at follow-up (n = 42), those affected by long COVID (n = 22) presented lower 25(OH) vitamin D levels at follow-up than those not affected (n = 20) (12.7 vs 15.2 ng/mL, P = .041). In multiple regression analyses, lower 25(OH) vitamin D levels at follow-up were the only variable significantly associated with long COVID in our cohort (P = .008, OR 1.09, CI 1.01-1.16).

CONCLUSION

COVID-19 survivors with long COVID have lower 25(OH) vitamin D levels than matched patients without long COVID. Our data suggest that vitamin D levels should be evaluated in COVID-19 patients after hospital discharge. The role of vitamin D supplementation as a preventive strategy of COVID-19 sequelae should be tested in randomized controlled trials.

Vitamin D status in non-pregnant women of reproductive age: a study in Southern Thailand

Vitamin D inadequacy is a global problem in all age groups. Although there are various studies of vitamin D status in pregnant women in Southeast Asia, to date there are few studies from Southeast Asia examining vitamin D status in non-pregnant women of reproductive age. To examine the prevalence of vitamin D insufficiency (VDI) in healthy non-pregnant women of reproductive age in Southern Thailand, 120 healthy non-pregnant women aged 18-42 years were enrolled. Demographic and lifestyle data relevant to vitamin D assessment (sunlight exposure, nutritional intake, type of dress, sunscreen use) and biochemical studies (serum 25-hydroxyvitamin D or 25OHD, parathyroid hormone, calcium, phosphate) were obtained. VDI was classified as serum 25OHD < 20 ng/mL. The average serum 25OHD level was 23.1 ± 6.0 ng/mL. The overall prevalence of VDI was 34.1%. The average dietary intake of calcium, phosphorus and vitamin D and the average duration of sunlight exposure per week were not significantly different between the VDI women and the vitamin D sufficient (VDS) women. Logistic regression analysis found that the significant risk factors for VDI were greater body mass index and higher family income (p-values 0.01 and 0.02, respectively). The prevalence of VDI in non-pregnant women was high at 34%. As the dietary sources of vitamin D are limited and cutaneous vitamin D synthesis is limited by avoidance of sunlight exposure, vitamin D fortification in common daily foods would be an alternative option to reach the recommended vitamin D intake generally of at least 800 IU/day.

Use of vitamins and/or minerals among adults and the elderly in urban areas of Brazil: prevalence and associated factors

The purpose of the present study was to estimate the prevalence of vitamin and/or mineral use among urban Brazilian populations aged 20 years and over and to identify associated factors. Data from the National Survey on Access, Use and Promotion of the Rational Use of Medicines in Brazil (PNAUM) were analyzed and a population-based cross-sectional study with probability sampling was performed in urban areas of Brazil's five geographic regions from September 2013 to February 2014. The estimated prevalence of vitamin and/or mineral use was 4.8% (95%CI: 4.3-5.3), higher in women 6.4% (95%CI: 5.7-7.1) and in the elderly population 11.6% (95%CI: 10.5-12.8). Vitamin and/or mineral use was associated with the following factors: women, 60 years of age or older, economic class A/B, chronic disease(s) and self-perceived health held as average and very poor/poor. Multivitamins and multiminerals were the most used ones with 24.5% (95%CI 20.1-29.4), followed by calcium and vitamin D with 23.4% (95%CI 19.7-27.5). Data suggest that elderly women should be the reference public for actions aimed at promoting rational use. Nationwide epidemiological surveys should increase monitoring of these products to support the analysis of trends.

Free and bioavailable 25-hydroxyvitamin D thresholds for bone metabolism and their associations with metabolic syndrome in Chinese women of childbearing age

Objective

The free hormone hypothesis suggests that free and bioavailable 25-hydroxyvitamin D [25(OH)D] may better reflect vitamin D bioactivity. This study aimed to determine the free and bioavailable 25(OH)D characteristics, estimate their thresholds based on parathyroid hormone (PTH) and bone turnover markers (BTMs), assess their associations with the risk of metabolic syndrome (MetS), and evaluate their potential advantages.

Methods

A cross-sectional study was conducted using a nationally representative database (n = 1,505, female, 18-45 years). Serum total 25(OH)D, vitamin D-binding protein, albumin, PTH, and BTMs [osteocalcin, β-CrossLaps of type 1 collagen containing cross-linked C-telopeptide (β-CTX), and procollagen type 1 N-terminal propeptide (P1NP)] were measured. Free 25(OH)D and bioavailable 25(OH)D were calculated. The threshold associations of 25(OH)D with PTH and BTMs were analyzed. The relationship between 25(OH)D and MetS risk was examined. An intervention study was then performed in 39 women (18-47 years) to assess the associations of increasing 25(OH)D with PTH and BTMs after vitamin D supplementation.

Results

In the cross-sectional study, the three forms of 25(OH)D were found to have similar distribution characteristics. Free and bioavailable 25(OH)D correlated well with total 25(OH)D. Significant total 25(OH)D cutoffs were observed for PTH (14.19 ng/mL and 18.03 ng/mL), osteocalcin (15.14 ng/mL), β-CTX (14.79 ng/mL), and P1NP (15.08 ng/mL). Free and bioavailable 25(OH)D cutoffs were only found for P1NP (3.47 pg/mL and 1.66 ng/mL, respectively). A total 25(OH)D of <15.14 ng/mL was marginally associated with a higher risk of reduced high-density lipoprotein cholesterol (HDL-C) [odd ratios (OR) = 1.371 (0.991-1.899)]. The ORs of higher versus lower free and bioavailable 25(OH)D levels for reduced HDL-C were 0.770 (0.621-0.956) and 0.772 (0.622-0.958), respectively. The results of the intervention study indicated that PTH and BTMs responded more sensitively to total 25(OH)D than to free or bioavailable 25(OH)D.

Conclusion

Free and bioavailable 25(OH)D only had a threshold effect on P1NP. The active 25(OH)D thresholds could be used for risk assessment of reduced HDL-C. However, no superiority of free or bioavailable 25(OH)D was found based on the response of PTH and BTMs to changes in 25(OH)D in Chinese women of childbearing age following vitamin D supplementation.

Clinical trial registration

http://www.chictr.org.cn, ChiCTR2200058290.

National monitoring of iodine, sodium, and vitamin D status in toddlers and women of childbearing age - results and lessons learned from a pilot study in Norway

Background

Norway is lacking a population-based national monitoring program for iodine, sodium, and vitamin D status.

Objective

The aim of this study was to pilot-test a study design for collecting biological samples from a country-representative sample of 2-year-old children and their mothers and to report results for iodine, salt, and vitamin D at baseline, before initiation of salt iodization in Norway.

Design

In a cross-sectional study, we recruited 2-year-old children and their mothers during the routine 2-year check-up through 38 randomly selected health clinics in 2021. Spot urine samples were analyzed for iodine, creatinine, and sodium, and dried blood spots from the mothers were analyzed for thyroglobulin (Tg) and 25-hydroxyvitamin D (25(OH)D).

Results

We aimed at including 400 mother-child pairs but recruited only 55 pairs. Major challenges were closed health clinics due to the COVID-19 pandemic, lack of motivation of the health personnel to prioritize recruiting, missing information about non-participation, and high workload for participants. The median urinary iodine concentration (UIC) was 123 (95% CI: 76, 228) µg/L in the toddlers and 83 (95% CI: 72, 99) µg/L in the mothers. The median urinary sodium concentration (UNaC) was 62 (95% CI: 37, 91) mmol/L in the toddlers and 93 (95% CI: 77, 107) mmol/L in the mothers. Of the mothers, 18% had levels of 25(OH)D <50 nmol/L (suboptimal status).

Discussion and conclusion

Lessons learned from the pilot study will be used to design a national monitoring program for toddlers and women of childbearing age in Norway. The results indicate that 2-year-old children and women of childbearing age in Norway may have inadequate iodine intakes at the group level, while for vitamin D, most of the mothers had adequate status.

Vitamin D Deficiency (VDD) and Benefits of Supplementation in Veterans with IBS-D

Many veterans deployed to Gulf War areas suffer from persistent chronic diarrhea that is disabling and affects their quality of life. The causes for this condition have eluded investigators until recently and recent literature has shed light on the effect of vitamin D on the brain-gut axis. This study focused on determining clinical causes contributing to diarrhea and assessed whether reversing the identified causes, specifically vitamin D deficiency (VDD), could reduce the incidence of diarrhea in Gulf War veterans (GWVs). All patients completed a workup that included serologies (IBD, celiac), routine laboratory tests (CBC, chemistry panels, TSH, T4, CRP), cultures for enteric pathogens (C diff, bacteria, viruses, small intestinal bacterial overgrowth (SIBO)), and upper and lower endoscopies with histology and a trial of cholestyramine to exclude choleretic diarrhea and rifaximin for dysbiosis. A total of 4221 veterans were screened for chronic diarrhea, yielding 105 GWVs, of which 69 GWVs had irritable bowel syndrome with diarrhea (IBS-D). Paired t-tests demonstrated that all GWVs had VDD (t-11.62, df68 and sig(2-tailed) 0.0001) (defined as a vitamin D level less than 30 ng/mL with normal ranges of 30-100 ng/mL) but no positive serologies, inflammatory markers, abnormal endoscopies, cultures, or histology to explain their persistent diarrhea. There was no correlation with age, BMI, or inflammation. Some zip codes had a higher frequency of GWVs with VDD, but the number of deployments had no impact. Treatment with vitamin D supplementation (3000-5000 units), given in the morning, based on weight, reduced the number of bowel movements per day (p < 0.0001) without causing hypercalcemia. We suggest that VDD is important in the etiology of IBS-D in GWVs and that vitamin D supplementation significantly reduces diarrhea.

Healthy lifestyles are associated with better vitamin D status in community-dwelling older men: The Health In Men Study (HIMS)

OBJECTIVE

Older people are more prone to vitamin D deficiency than younger populations. Individual lifestyle factors have been associated with vitamin D status. We examined the influence of a combination of lifestyle factors on vitamin D status in older men.

PARTICIPANTS AND MEASUREMENTS

In a population-based cohort study of older men (age ≥65 years), a lifestyle score was calculated from eight prudent health-related behaviours (smoking, exercise, alcohol, fish and meat consumption, adding salt, milk choices and obesity) collected via questionnaire at baseline. Blood samples were collected 5 years afterwards to measure plasma 25-hydroxyvitamin D (25OHD) levels. Associations between lifestyles and the likelihood of having plasma 25OHD levels of ≥75 versus <75 nmol/L and ≥50 versus <50 nmol/L were tested using logistic regression models.

RESULTS

Of the 2717 men analysed, mean plasma 25OHD was 69.0 ± 23.5 nmol/L, with 20.7% having plasma 25OHD <50 nmol/L. Men engaging in ≥4 healthy lifestyle behaviours had 20% higher odds of plasma 25OHD ≥75 nmol/L (adjusted OR = 1.20, 95% CI: 1.01-1.45) compared to those with <4 healthy behaviours. No association was found for 25OHD ≥50 nmol/L. Higher physical activity was the only individual component significantly associated with vitamin D sufficiency (highest vs. lowest quintiles of physical activity, adjusted OR = 2.01, 95% CI: 1.47-2.74 for 25OHD ≥50 nmol/L, adjusted OR = 2.35, 95% CI: 1.81-3.06 for 25OHD ≥75 nmol/L).

CONCLUSION

Multiple healthy lifestyle behaviours are associated with better vitamin D status in older men. Further work is needed to determine the effects of promoting healthy lifestyle behaviours, including physical activity, on vitamin D sufficiency.

Gene-environment interaction in the association of residential greenness and 25(OH) vitamin D

There is increasing awareness for beneficial health effects of green space surrounding the home, but the underlying mechanisms are not yet fully understood and challenging to study given the correlation with other exposures. Here, the association of residential greenness and vitamin D including a gene-environment interaction is investigated. 25-hydroxyvitamin D (25(OH)D) was measured by electrochemiluminescence at ages 10 and 15 years in participants of two German birth cohorts GINIplus and LISA. Greenness was measured using the Landsat-derived Normalized Difference Vegetation Index (NDVI) in a 500 m buffer surrounding the home. Linear and logistic regression models were applied at both time points adjusted for several covariates (N_10Y = 2,504, N_15Y = 2,613). In additional analyses vitamin D-related genes, physical activity, time spent outdoors, supplements, and measurement season were investigated as potential confounders or effect modifiers. A 1.5-SD increase in NDVI was significantly associated with increased 25(OH)D values at ages 10 and 15 years (β_10y = 2.41 nmol/l, p=<0.01; β_15y = 2.03 nmol/l, p = 0.02). In stratified analyses, the associations were not seen in participants spending more than 5 h/day outside in summer, having a high physical activity level, taking supplements, or being examined during the winter season. In a subset (n = 1,732) with genetic data, a significant gene-environment interaction of NDVI with CYP2R1, an upstream gene in 25(OH)D synthesis, was observed at age 10 years. When investigating 25(OH)D sufficiency, defined as values above 50 nmol/l, a 1.5-SD increase in NDVI was associated with significantly higher odds of having sufficient 25 (OH)D levels at age 10 years (OR = 1.48, 1.19-1.83). In conclusion, robust associations between residential greenness and 25 (OH)D levels were observed in children and adolescents independent of other confounders and additionally supported by the presence of a gene-environment interaction. Effects of NDVI were stronger in those having lower vitamin D levels at age 10 years due to their covariate profile or genetically lower 25(OH)D synthesis.

A Scoping Review of Vitamin D for Nonskeletal Health: A Framework for Evidence-based Clinical Practice

BACKGROUND

Low serum 25-hydroxy-vitamin D [25(OH)D] levels are prevalent worldwide. Although the benefits of vitamin D supplementation have focused on skeletal disorders (eg, rickets, osteomalacia, osteoporosis), emerging evidence for nonskeletal health merits further discussion.

PURPOSE

The purpose of this review was to critically examine the vitamin D supplementation literature pertaining to nonskeletal health to help guide clinicians.

METHODS

A scoping review that included observational studies and randomized clinical trials (RCTs) was performed. Evidence from meta-analyses and individual RCTs are discussed, and controversies and future directions are considered.

FINDINGS

25(OH)D deficiency is a ubiquitous condition associated with multiple nonskeletal diseases, including cardiometabolic (heart disease, diabetes, and kidney disease), immune (HIV/AIDS and cancer), lung (from traditional chronic disorders to coronavirus disease 2019), and gut diseases. Vitamin D deficiency also affects health across the life span (children, pregnant, and elderly), mental illness, and reproduction in both men and women. In contrast, vitamin D supplementation does not necessarily improve major medical outcomes, even when low 25(OH)D levels are treated. Screening for 25(OH)D status remains an important practice, primarily for high-risk patients (eg, elderly, women with osteoporosis, people with low exposure to sunlight). It is reasonable to supplement with vitamin D to treat 25(OH)D deficiency, such that if beneficial nonskeletal health occurs, this may be considered as a coadjutant instead of the central tenet of the disease. Furthermore, optimizing dosing regimens is an important clinical consideration.

IMPLICATIONS

Although 25(OH)D deficiency is prevalent in nonskeletal diseases, there is no uniform evidence that vitamin D supplementation improves major medical outcomes, even when low 25(OH)D levels are corrected. Findings from RCTs warrant caution due to possible selection bias. Overall, vitamin D supplementation must be guided by circulating levels as a reasonable medical practice to correct 25(OH)D deficiency.