Vitamin D deficiency in Europe: pandemic?

Effect of different food matrices on the bioaccessibility of vitamin D3 in beverage systems: Comparison between juice and liquid milk

Vitamin D plays a crucial role in bone, immunology, and neurophysiological functions but has inadequate bioavailability in the human body. In this paper, six different liquid beverages were used for vitamin D3 fortification, investigating the effect of different food matrices on the bioaccessibility of vitamin D. Not from concentrate (NFC) apple juice (9.34%) and NFC orange juice (8.12%) presented about 20% higher bioaccessibility of vitamin D3 than soybean and skim milk, and achieved a similar value of whole milk (8.04%). Meanwhile, the bioaccessibility of NFC apple and orange juice was markedly about 120% higher than that of apple clear juice. From the correlation analysis, the bioaccessibility of VD3 indicated significant correlations with small intestine retention (0.82) and viscosity (0.66). But small intestinal particle size showed a negative effect on bioaccessibility (-0.78). Therefore, food components, delivery matrices, and physicochemical properties of digesta were key factors to achieve higher bioaccessibility for guiding formulation design.

Can micronutrient requirements be met by diets from sustainable sources: outcomes of dietary modelling studies using diet optimization

BACKGROUND

Consumption of diets from sustainable sources is required for planetary health, however, large sections of the population, including females of reproductive age and children, will be at risk of not meeting their micronutrient (MN) requirements in a complete transition to plant-based foods. Constrained diet optimization methods use mathematical programming to construct diets that meet predefined parameters and may contribute towards modelling dietary solutions that meet nutritional and planetary targets.

OBJECTIVE

Review the evidence from diet optimization studies proposing solutions to ensure MN availability in the context of a transition to diets from sustainable sources.

APPROACH

Narrative review focusing on literature published over the last five years.

RESULTS

Dietary modelling using diet optimization can design a range of omnivorous and plant-based diets that meet individual MN requirements, have reduced environmental impacts, and minimize deviation from culturally acceptable dietary practices. Using data from large-scale dietary surveys, diet optimization can support development of food-based dietary guidelines; identify limiting MNs in a particular context or a conflict between constraints e.g. nutrition and environment; explore food-based strategies to increase nutrient supply, such as fortification; and support trial design. Methods used and outcomes reported are sources of variability. Individual-level dietary data and MN requirements for population sub-groups such as females of reproductive age and children are important requirements. Although maintaining iron and zinc intakes are regularly reported to present challenges in diets from sustainable sources, few studies have considered bioavailability, which reduces with increased dietary phytate. These and other data gaps including acceptability and affordability must be addressed to improve the applicability of modelling outcomes in population recommendations.

CONCLUSIONS

Dietary modelling using diet optimization can be useful in the design of more sustainable diets that meet MN requirements, however, translation of outcomes into dietary intervention studies is required to test real-world application and adoption into dietary guidelines.

Daylight quality: high-transmittance glass versus low transmittance glass - effects on daylight quality, health, comfort and energy consumption

Introduction: This study investigated the health effects of two different architectural glass types: A two-layered low-iron high transmittance glass and a three-layered low energy glass with lower transmittance. The study investigated how these glass types affected daylight conditions in 72 residential apartments, as well as health and satisfaction of the residents.Methods: The study installed high transmittance glass (light transmittance LT:0.82) in 36 apartments and low transmittance (LT:0.74) in 36 identical apartments. The study then analyzed the light transmittance of each glass type in the laboratory and analyzed the indoor environmental quality (IEQ) in eight representative apartments before and after renovation. Self-reported questionnaires were handed out and collected before and after renovation.Results: The results showed that the glass types differed significantly in measured daylight transmittance. The two-layered high transmittance glass transmitted 15% more visual light (380-750 nm) and 20% more light in the spectral range (460-480 nm), stimulating ipRGCs and circadian rhythm, when compared to three-layered low energy glass. In addition, significant differences were observed in the UV-B spectrum (280-315 nm). While two-layered high transmittance glass transmitted UV-B, three-layered low transmittance glass did not. During the 12-month study period, residents in apartments with three-layered low energy glass reported more difficulties sleeping (p = 0.05), higher satisfaction with daylight (p = 0.03) and higher satisfaction with ventilation (p = 0.04). Residents in apartments with three-layered low energy glass experienced fewer days with too cold indoor temperatures (p = 0.02), compared to residents with two-layered low-iron glass. The results of energy consumption for heating showed that two-layered low-iron glass reduced the energy consumption by 11.0%, while three-layered low energy glass reduced the energy consumption by 9.4%, compared to the year prior to renovation.Conclusion: The results contribute to a discussion about potential energy savings on one hand and potential non-energy benefits, such as daylight quality, overall health, and total economy/life cycle assessment of the built environment on the other hand. The results suggest further research performed in randomized large-scale studies.

An error in concept and definition of recommended dietary allowance developed in 1941: Time to create new ones

The recommended dietary allowance (RDA) for vitamin C differs greatly (40-110 mg/d) across countries. In addition, vitamin D deficiency is, effectively, a pandemic, with a prevalence of approximately 25% to 80% across countries according to the findings in the recent scientific literature. However, these phenomena are attributable to a serious error in the concept and definition of RDA, which was developed in 1941. The current definition of RDA is the average daily dietary nutrient intake level that is deemed sufficient to meet the nutrient requirements of almost all (97-98%) healthy individuals. This is an extremely high intake level for a specific nutrient affecting only a few individuals (the upper 2.5%) of the generally healthy population. The RDA should be redefined by investigating at which intake level of a specific nutrient the incidence of a specific disease or mortality increases or decreases based on prospective cohort studies.

The association between dynamic changes in vitamin D and frailty alterations: A prospective analysis of UK Biobank participants

BACKGROUND

Frailty is a common geriatric syndrome associated with reduced reserves and increased vulnerability to stressors among older adults. Vitamin D deficiency has been implicated in frailty, as it is essential for maintaining musculoskeletal functions. The relationship between dynamic changes in vitamin D levels and frailty over time has not been extensively studied.

METHODS

This study utilized data from the UK Biobank. Baseline and longitudinal changes in vitamin D levels were measured. Frailty status was assessed using both the frailty phenotype and frailty index approaches and classified as robust, pre-frail, or frail. Changes in frailty status were assessed by frailty phenotype at baseline (2006-2010) and the follow-up (2012-2013). Mixed effect model was performed to examine the association between vitamin D levels and frailty status. Using multistate transition models, we assessed the impact of increasing vitamin D levels on the probabilities of transitioning between robust, pre-frail, and frail states.

RESULTS

Based on the frailty phenotype, 287 926 individuals (64.8%) were identified as having various degrees of frailty (median age 58.00 [51.00, 64.00] years, 55.9% females). Using the frailty index approach, 250 566 individuals (56%) were found to have different levels of frailty (median age 59.00 [51.00, 64.00] years, 55.3% females). Baseline vitamin D levels were found to be significantly associated with frailty status (frailty phenotype: ORfrail 0.78, 95% CI [0.76, 0.79], P < 0.001; frailty index: ORfrail 0.80, 95% CI [0.78, 0.81], P < 0.001). Dynamic changes in vitamin D levels were also found to be associated with changes in frailty over time. Furthermore, increasing vitamin D levels were associated with a transition from frailty to a healthier status. A higher degree of vitamin D (estimated at 1 nmol/L) was associated with a lower risk of transitioning from robust to prefrail (HR 0.997, 95% CI [0.995, 0.999]) and from prefrail to frail (HR 0.992, 95% CI [0.988, 0.995]).

CONCLUSIONS

This study highlights the importance of vitamin D in the context of frailty. Low vitamin D levels are associated with increased frailty risk, while increasing vitamin D levels may contribute to improving frailty status. Recognizing the relationship between vitamin D levels and frailty can inform personalized management and early interventions for frail individuals. Further research is needed to explore the potential effects of vitamin D interventions on frailty and deepen our understanding of the biological connections between vitamin D and frailty.

Predicted vitamin D levels and risk of depression in the SUN Project: A prospective cohort study

The current study aimed to investigate the association between predicted vitamin D status and depression in a prospective Spanish cohort of university graduates. The SUN Project is a dynamic cohort study designed to investigate multiple aspects of health and lifestyle. Participants were asked to complete a comprehensive questionnaire consisting of 556 items, that included a validated food-frequency questionnaire. Participants initially free of depression were classified as incident cases if they reported a medical diagnosis of depression during follow-up. Serum vitamin D levels were predicted by a previously validated equation. Vitamin D deficiency was defined as vitamin D levels below 20 ng/mL. Cox models were used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (95% CI). We included 15,175 Spanish university graduates [mean (SD) age: 36.9 year (11.5)] followed-up for a median of 12.7 years. Among 192,976 person-years of follow-up, we identified 753 incident cases of depression. Participants with vitamin D deficiency had a 27% higher risk of depression as compared to those with vitamin D sufficiency (HR: 1.27, 95% CI: 1.09-1.48; p = 0.002) after adjusting for potential confounders. Furthermore, a significant effect modification by female sex was observed with higher depression risks associated with vitamin D deficiency in women than in men (p for interaction = 0.034). In educated middle-aged Spanish adults, we observed a direct association between vitamin D deficiency and the risk of depression, that was stronger among women.

The effect of vitamin D supplementation on markers of insulin resistance in women with polycystic ovarian syndrome: a systematic review

BACKGROUND

Insulin resistance (IR) is a common pathology in women with polycystic ovarian syndrome (PCOS) involved in increased rates of cardiometabolic disease such as diabetes and cardiovascular disease. Low serum vitamin D is often associated with insulin resistance but there is no consensus on whether vitamin D supplementation can ameliorate markers of IR in PCOS.

OBJECTIVES

We assessed evidence on the effects of vitamin D supplementation (≥ 1000 IU/day), without the use of additional supplements or other pharmacological treatments known to affect IR, on markers of IR and glycemic control in women with PCOS.

DESIGN

A systematic search was conducted using PubMed, Medline and Web of Science databases from January 2000 up to November 2023. Randomized controlled trials that assessed the effects of vitamin D supplementation in women with PCOS, on fasting glucose, fasting insulin, glycated haemoglobin (HbA1c) or homeostatic model assessment for insulin resistance (HOMA-IR) were included.

RESULTS

9 studies were identified. Study populations ranged from 28 to 180 participants, with mean ages ranging from 22 to 30 years. Daily vitamin D doses ranged from 1714-12,000 IU. Of the included studies, 3 reported statistically significant reductions in fasting glucose, 2 reported reductions in fasting insulin, 2 reported reductions in HOMA-IR, none reported reductions in HbA1c and 5 reported no differences in any of the relevant outcomes.

CONCLUSIONS

In conclusion, in RCTs of vitamin D supplementation in women with PCOS, the majority of studies do not report statistically significant improvements in fasting glucose, fasting insulin, HbA1c or HOMA-IR. However, as a minority of studies report some statistically significant results, further investigation may be warranted.

REGISTRY

PROSPERO ID: CRD42023486144.

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.

Vitamin D: Analytical Advances, Clinical Impact, and Ongoing Debates on Health Perspectives

BACKGROUND

Vitamin D, acknowledged since the 1930s for its role in preventing rickets, gained additional prominence in relation to fragility fracture prevention in the late 1980s. From the early 2000s, connections between vitamin D deficiency and extra-skeletal pathologies emerged, alongside increased awareness of widespread deficits. This prompted crucial debates on optimal serum concentrations, expected to conclude when the outcomes of high-dose supplementation randomized controlled trials were available. Skepticism arose with inconclusive results from these trials.

CONTENT

This review begins with an exploration of vitamin D metabolism, followed by a detailed description of the measurement of vitamin D metabolites and the crucial role of standardization. Subsequent sections focus on the association of vitamin D with bone health and explore the extra-skeletal effects. The review concludes with a comprehensive discussion on the definition of vitamin D status and its implications for supplementation.

SUMMARY

Despite standardization efforts, assay variations and challenges still exist, especially in specific patient groups. Vitamin D supplementation has a significant impact on bone metabolism and optimal vitamin D status improves the efficacy of antiresorptive drugs such as bisphosphonates. The extra-skeletal effects of vitamin D remain debated, but may include potential benefits in conditions such as respiratory infections and cancer mortality, particularly in deficient individuals. The definition of vitamin D sufficiency is nuanced, especially when variations in population groups and analytical methods are taken into account. Despite ongoing debates and recent mega-trials tempering enthusiasm, vitamin D remains a complex and essential element in human health. Further research is needed to clarify its role in various health outcomes and guide supplementation strategies.

Animal board invited review: Dietary transition from animal to plant-derived foods: Are there risks to health?

Animal-derived foods (ADFs) are a very varied group of foods, but many are nutrient rich and contain higher quality protein than provided by plant-derived foods such that a simple replacement of ADF protein is likely to lead to a reduction in overall protein quality. In addition, many ADFs are richer in some nutrients than plant-based foods (e.g. Fe, Ca) and these often have a higher bioavailability. ADFs also provide nutrients that plants cannot supply (e.g. vitamin B12) and some provide beneficial health functionality (e.g. hypotensive) which is not explained by traditional nutrition. However, there remains a good health reason to increase the proportion of plant-derived food in many diets to increase the intake of dietary fibre which is often consumed at very sub-optimal levels. It seems logical that the increased plant-derived foods should replace the ADFs that have the least benefit, the greatest risk to health and the highest environmental impact. Processed meat fits these characteristics and should be an initial target for replacement with plant-based based protein-rich foods that additionally provide the necessary nutrients and have high-quality dietary fibre. Processed meat covers a wide range of products including several traditional foods (e.g. sausages) which will make decisions on food replacement challenging. There is therefore an urgent need for research to better define the relative health risks associated with the range of processed meat-based foods. The aim of this review is to examine the evidence on the benefits and risks of this dietary transition including the absolute necessity to consider initial nutrient status before the replacement of ADFs is considered.

The relationship between serum vitamin D, testosterone, and oxidative stress levels in women with sexual dysfunction: A case-controlled study

OBJECTIVE

Female sexual dysfunction (FSD) is highly prevalent and can result from hypovitaminosis D. Besides the role of vitamin D in normal bone development, studies showed it could reduce oxidative stress and lipid peroxidation. This prospective study aims to evaluate the relationship between serum vitamin D, testosterone, and oxidative stress levels in women with FSD.

MATERIALS AND METHODS

In this cross-sectional study, a total of 40 women with FSD (age range: 18-45 years) were randomly assigned into two groups of intervention and control. In the intervention group, patients received vitamin D 300,000 IU intramuscularly (IM) and then 50,000 IU orally once a week for four weeks. We measured the serum vitamin D, testosterone, and oxidative stress levels, as well as the Female Sexual Function Index (FSFI) at baseline and monthly for three months.

RESULTS

Serum testosterone levels significantly increased in the intervention group at the end of the third month (P = 0.014). Also, FSFI scores significantly improved (P < 0.01) in the intervention group compared to the control group. While there was positive a correlation between serum vitamin D levels with glutathione, total antioxidant capacity (TAC), testosterone, and FSFI score, there was a negative correlation between serum vitamin D levels with malondialdehyde (MDA), protein carbonyl, and nitric oxide.

CONCLUSION

We witnessed that women with FSD had low serum vitamin D levels. So, modifying serum vitamin D levels must be considered as a treatment option. Moreover, vitamin D supplementation improved testosterone, serum oxidative stress, and sexual function.

Serum 25-hydroxyvitamin D levels and risk of all-cause and cause-specific mortality: A 14-year prospective cohort study

BACKGROUND & AIMS

The circulating vitamin D level that is optimal for health is unknown. This study aimed to examine the association between circulating vitamin D level and risk of all-cause and cause-specific mortality.

METHODS

This prospective cohort study included 18,797 Korean adults aged 40 years or older, living in rural areas, with no history of cancer or cardiovascular disease (CVD) at baseline. Serum 25-hydroxyvitamin D (25(OH)D) levels were measured at baseline. Participants were followed-up from the survey date (2005-2012) until December 31, 2021. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality by baseline vitamin D level. Restricted cubic splines were used to explore the nonlinearity.

RESULTS

The median (interquartile range) of 25(OH)D level was 55.8 (40.8-71.8) nmol/L. During a median follow-up of 14.3 years, 2250 deaths were recorded. Compared with participants with a 25(OH)D level <30 nmol/L, higher vitamin D levels (30 to < 50, 50 to < 75, and ≥75 nmol/L) were associated with a lower risk of all-cause mortality: HR (95% CI) of 0.82 (0.69-0.98), 0.74 (0.62-0.88), and 0.69 (0.57-0.84), respectively. A nonlinear relationship between vitamin D level and all-cause mortality was observed, with the risk plateauing between 50 and 60 nmol/L (p for nonlinearity = 0.009). The association was more pronounced for cancer-related mortality. HR 0.55 (95% CI: 0.39-0.77) for a 25(OH)D level ≥75 nmol/L compared with <30.0 nmol/L. Low vitamin D levels were associated with increased CVD mortality in men.

CONCLUSIONS

Vitamin D level was inversely associated with all-cause and cause-specific mortality in middle-aged and older adults. Maintaining a serum 25(OH)D level of approximately 50-60 nmol/L may contribute to longevity and warrants further investigation.

Impact of plasmolysis process on the enrichment of brewer's spent yeast biomass with vitamin D3 by biosorption followed by spray-drying process

Vitamin D3(cholecalciferol)plays a crucial role in various physiological processes. However, vitamin D3 deficiency is a major public health problem affecting millions of people. Therefore, it is important to develop effective strategies that ensure the protection and stability of this important vitamin for food supplementation and fortification. This work aimed to impregnate intact and plasmolyzedSaccharomyces pastorianus brewer's yeast biomass with cholecalciferol using a biosorption process followed by spray drying to characterize the obtained material in terms of morphology, average particle size, zeta potential, moisture, water activity, FT-IR, and the stability of the encapsulated vitamin during the drying and storage process. Plasmolysis proved to be an effective method for improving the biosorption efficiency, retention during spray drying, and stability of vitamin D3. In addition, this process promoted an increase in cell size, which favored the dispersion stability of the system, as evidenced by the zeta potential values. These results contribute to the understanding of a new method for delivering this vitamin that conforms to environmentally conscious practices.

Vitamin D and risk of developing type 2 diabetes in the SUN project: a prospective cohort study

PURPOSE

Vitamin D deficiency has been associated with multiple chronic diseases, including metabolic disorders such as insulin resistance and type 2 diabetes (T2D). The aim of the study was to analyze the association between validated predicted serum vitamin D status and the risk of developing T2D in a large prospective cohort based on a Mediterranean population.

METHODS

The SUN project is a prospective and dynamic Spanish cohort that gathers university graduates who have answered lifestyle questionnaires, including a validated Food Frequency Questionnaire. The association between predicted serum vitamin D and the risk of T2D was assessed through Cox regression models according to quartiles (Q) of predicted vitamin D at baseline. The models were adjusted for potential confounders and sensitivity analyses were performed to ensure the robustness of our findings.

RESULTS

Our study included a total of 18,594 participants and after a total follow-up of 238,078 person-years (median follow-up of 13.5 years), 209 individuals were diagnosed with incident T2D. We found a significant inverse association between predicted levels of serum vitamin D and the risk of developing T2D, after adjusting for potential confounders and performing different sensitivity analyses (hazard ratio Q4 vs. Q1: 0.48, 95% CI 0.26-0.88; p for trend = 0.032).

CONCLUSION

The outcomes suggest that higher levels of vitamin D at baseline may be associated with a reduced risk of developing T2D.

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.

Vitamin D Deficiency-A Public Health Issue in Children

BACKGROUND

25-hydroxyvitamin D [25(OH)D] deficiency is a global health concern, particularly in pediatric populations, with implications for musculoskeletal health and overall well-being. This study aimed to evaluate serum 25(OH)D levels in a pediatric population and assess the prevalence of deficiency and insufficiency.

METHODS

A retrospective analysis was conducted on data from 741 pediatric patients (2-17 years old) who visited an urban hospital for children for acute respiratory and gastrointestinal conditions in the span of 2 years. Serum 25(OH)D levels were measured using chemiluminescent microparticle immunoassay. Statistical analyses were performed to assess the prevalence of deficiency and insufficiency, seasonal variations, and correlations with age and daylight exposure.

RESULTS

Of the 739 pediatric patients analyzed, a substantial proportion exhibited insufficient (31.80%) or deficient (36.54%) serum 25(OH)D levels. While younger age groups generally had higher mean 25(OH)D levels, a negative correlation was observed between 25(OH)D levels and age. Sunlight exposure variations did not significantly impact serum 25(OH)D levels. Despite diverse daylight exposure patterns, there were no significant differences between longer and shorter daylight periods.

CONCLUSIONS

This study highlights the high prevalence of 25(OH)D deficiency and insufficiency in the pediatric population, emphasizing the need for public health monitoring and targeted supplementation strategies. Findings underscore the importance of regular consultations with healthcare providers to ensure optimal 25(OH)D levels in children, with potential implications for revising current sufficiency thresholds. Addressing 25(OH)D deficiency is crucial for promoting musculoskeletal health and overall well-being in children.

The effects of cholecalciferol and afamelanotide on vitamin D levels in erythropoietic protoporphyria: a multicentre cohort study

BACKGROUND

Patients with erythropoietic protoporphyria experience lifelong painful photosensitivity resulting in a lack of sunlight exposure. Previous studies have shown that 47-63% of patients with EPP suffer from vitamin D deficiency and a high prevalence of osteoporosis. An effective treatment for EPP has been available since 2016: the α-melanocyte stimulating hormone analogue afamelanotide. So far, studies on vitamin D levels in EPP have only investigated patients who have not been treated with afamelanotide.

OBJECTIVES

To investigate the effects of afamelanotide treatment on vitamin D levels in EPP.

METHODS

A multicentre observational cohort study in adults with EPP from the Erasmus Medical Centre, the Netherlands, and the University Hospital Düsseldorf, Germany, was carried out. Routinely collected vitamin D levels between 2005 and 2021 were used for analysis. Patient exposure to cholecalciferol or afamelanotide was categorized into four treatment groups: untreated, cholecalciferol, afamelanotide and combined treatment. A linear mixed model for longitudinal data was applied to measure the effect of the treatment groups compared with the untreated groups on vitamin D levels.

RESULTS

A total of 230 patients and 1774 vitamin D measurements were included. The prevalence of vitamin D deficiency and severe deficiency remained high despite afamelanotide treatment (< 50 nmol L-1 in 71.8% of patients and < 30 nmol L-1 in 48.1%, respectively). Afamelanotide treatment alone did not lead to a significant average increase in vitamin D levels [β = 0.5, 95% confidence interval (CI) -3.2 to 4.2]. In contrast, cholecalciferol and combined therapy with afamelanotide led to a significant increase in vitamin D levels [β = 11.6 (95% CI 7.2-15.9) and β = 15.2 (95% CI 12.3-18.1), respectively].

CONCLUSIONS

Cholecalciferol remains essential for the treatment of vitamin D deficiency in EPP, irrespective of new treatment options like afamelanotide. Afamelanotide treatment did not affect vitamin D levels. We suggest that future guidelines include continuous monitoring of vitamin D and a prescription for cholecalciferol in all patients with EPP, including those treated with afamelanotide.

Association between serum vitamin D status and severity of liver cirrhosis: implications for therapeutic targeting in Nigerian patients

BACKGROUND

Liver cirrhosis is a chronic and progressive liver disease with significant global health implications. Recent evidence suggests an association between serum vitamin D levels and the severity of liver cirrhosis, potentially serving as a therapeutic target. This study aimed to investigate the relationship between serum vitamin D status and the severity of liver cirrhosis in a population of Nigerian patients.

METHODS

This analytical, cross-sectional study involved 201 participants, including 103 with liver cirrhosis and 98 age- and sex-matched controls. Serum vitamin D was measured using ELISA, with deficiency defined as < 20 ng/ml. Cirrhosis severity was assessed using Child-Pugh and MELD scores. Spearman's correlation was used to assess the relationship between vitamin D and severity of liver cirrhosis while ordinal regression analysis assessed its performance as an indicator of the disease severity.

RESULT

Among cirrhotic patients, 36.9% were deficient, 31.1% insufficient, and 32.0% had sufficient vitamin D levels. Serum vitamin D showed strong negative correlations with Child-Pugh and MELD scores (r = -0.696, p < 0.001; r = -0.734, p < 0.001, respectively). Ordinal regression showed that higher vitamin D levels were associated with lower severity scores (Child-Pugh: OR = 0.856, 95% CI: 0.815-0.900, p < 0.001; MELD: OR = 0.875, 95% CI: 0.837-0.915, p < 0.001).

CONCLUSION

Lower serum vitamin D levels correlated with increased liver cirrhosis severity, suggesting its potential as both a prognostic marker and therapeutic target. Further studies should investigate the efficacy of vitamin D supplementation in improving cirrhosis outcomes.

Serum 25-hydroxyvitamin D concentrations, vitamin D receptor polymorphisms, and risk of infections among individuals with type 2 diabetes: a prospective cohort study

BACKGROUND

Evidence on the association between serum 25-hydroxyvitamin D [25(OH)D] and infections among patients with type 2 diabetes (T2D), a group susceptible to vitamin D deficiency and infections, is limited.

OBJECTIVES

We aimed to examine this association in individuals with T2D, and to evaluate whether genetic variants in vitamin D receptor (VDR) would modify this association.

METHODS

This study included 19,851 participants with T2D from United Kingdom Biobank. Infections were identified by linkage to hospital inpatient and death registers. Negative binomial regression models were used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CIs), with adjustment of potential confounders.

RESULTS

In patients with T2D, the incidence rate of infections was 29.3/1000 person-y. Compared with those with 25(OH)D of 50.0-74.9 nmol/L, the multivariable-adjusted IRRs and 95% CIs of total infections, pneumonia, gastrointestinal infections, and sepsis were 1.44 (1.31, 1.59), 1.49 (1.27, 1.75), 1.47 (1.22, 1.78), and 1.41 (1.14, 1.73), respectively, in patients with 25(OH)D <25.0 nmol/L. Nonlinear inverse associations between 25(OH)D concentrations and the risks of total infections (P-overall < 0.001; P-nonlinear = 0.002) and gastrointestinal infections (P-overall < 0.001; P-nonlinear = 0.040) were observed, with a threshold effect at ∼50.0 nmol/L. The vitamin D-infection association was not modified by genetic variants in VDR (all P-interaction > 0.050).

CONCLUSIONS

In patients with T2D, lower serum 25(OH)D concentration (<50 nmol/L) was associated with higher risks of infections, regardless of genetic variants in VDR. Notably, nonlinear inverse associations between 25(OH)D concentrations and the risks of infections were found, with a threshold effect at ∼50.0 nmol/L. These findings highlighted the importance of maintaining adequate vitamin D in reducing the risk of infections in patients with T2D.

Association of a dietary pattern related to serum vitamin D levels with metabolic syndrome risk among Korean adults: based on the Korean national health and nutrition examination survey

PURPOSE

Vitamin D has a crucial role in our metabolic health. We aimed to examine associations of vitamin D status and its related dietary pattern (DP) with prevalent risk of metabolic syndrome (MetS) in 9,237 Korean adults aged 19-64 years based on the National Health and Nutrition Examination Survey.

METHODS

Vitamin D status was examined by serum 25-hydroxyvitamin D (25(OH)D). A vitamin D-related DP associated with 25(OH)D levels was derived using reduced rank regression (RRR). Associations of vitamin D status and its related DP with MetS prevalence were examined using multivariable logistic regression models adjusted for potential confounders.

RESULTS

Men with sufficient vitamin D status had a 44% lower risk of MetS prevalence (OR: 0.56; 95%CI: 0.36-0.87) compared to those with deficiency. A vitamin D-related DP derived using RRR was characterized by high intakes of vegetables, fish, fruits, and nuts and low intakes of eggs, oils, and mushrooms in this study population. Among men, the DP was significantly associated with a lower risk of MetS prevalence, showing a 12% (95%CI: 4-20%) reduction in risk for a one-unit increase in the DP score. However, there was no significant association among women.

CONCLUSION

The study's findings suggest that a sufficient vitamin D status and a related DP with high intakes of vegetables, fish, fruit, and nuts were associated with the risk of MetS, particularly in Korean male adults.

Vitamin D and the Risk of Developing Hypertension in the SUN Project: A Prospective Cohort Study

Vitamin D deficiency has been associated with a higher risk of multiple diseases, including cardiovascular disorders. The purpose of this study was to examine the potential association between predicted levels of serum 25(OH)D and the risk of new-onset hypertension in a large Mediterranean cohort. A validated 136-item food frequency questionnaire was used as the dietary assessment tool. 25(OH)D serum levels were predicted using a previously validated equation. We performed Cox regression models to analyze the association between predicted serum 25(OH)D and the risk of hypertension, according to quartiles of forecasted vitamin D at baseline, after adjusting for multiple potential confounders. Over a median follow-up of 12.3 years, 2338 new cases of hypertension were identified. The analyses revealed a significant inverse association between predicted serum levels of 25(OH)D at baseline and the risk of hypertension. Individuals in the highest quartile showed a 30% relatively lower risk of hypertension compared to the lowest quartile (hazard ratio (HR): 0.70; 95% confidence interval (CI): 0.60-0.80, p-trend < 0.001). The outcomes remained significant after performing sensitivity analyses. The findings suggested that higher levels of forecasted vitamin D are inversely and independently associated with the risk of incident hypertension, implying that vitamin D may offer protective benefits against the disease.

Vitamin D status of pregnant women with obesity in the UK and its association with pregnancy outcomes: a secondary analysis of the UK Pregnancies Better Eating and Activity Trial (UPBEAT) study

Prenatal vitamin D deficiency is widely reported and may affect perinatal outcomes. In this secondary analysis of the UK Pregnancies Better Eating and Activity Trial, we examined vitamin D status and its relationship with selected pregnancy outcomes in women with obesity (BMI ≥ 30 kg/m2) from multi-ethnic inner-city settings in the UK. Determinants of vitamin D status at a mean of 17 ± 1 weeks' gestation were assessed using multivariable linear regression and reported as percent differences in serum 25-hydroxyvitamin D (25(OH)D). Associations between 25(OH)D and clinical outcomes were examined using logistic regression. Among 1089 participants, 67 % had 25(OH)D < 50 nmol/l and 26 % had concentrations < 25 nmol/l. In fully adjusted models accounting for socio-demographic and anthropometric characteristics, 25(OH)D was lower among women of Black (% difference = -33; 95 % CI: -39, -27), Asian (% difference = -43; 95 % CI: -51, -35) and other non-White (% difference = -26; 95 % CI: -35, -14) ethnicity compared with women of White ethnicity (n 1086; P < 0·001 for all). In unadjusted analysis, risk of gestational diabetes was greater in women with 25(OH)D < 25 nmol/l compared with ≥ 50 nmol/l (OR = 1·58; 95 % CI: 1·09, 2·31), but the magnitude of effect estimates was attenuated in the multivariable model (OR = 1·33; 95 % CI: 0·88, 2·00). There were no associations between 25(OH)D and risk of preeclampsia, preterm birth or small for gestational age or large-for-gestational-age delivery. These findings demonstrate low 25(OH)D among pregnant women with obesity and highlight ethnic disparities in vitamin D status in the UK. However, evidence for a greater risk of adverse perinatal outcomes among women with vitamin D deficiency was limited.

Vitamin D Status among 2-18-Year-Old Romanian Pediatric Patients: A Single-Center Study

An adequate vitamin D level is essential for optimal bone mass formation during growth. The present study aimed to assess (i) the sex-specific, age-specific, and potential seasonal (spring, summer, winter) influences on the pediatric circulating levels of 25-hydroxyvitamin D (25(OH)D); (ii) determine the frequency of pediatric patients with vitamin D deficiency (VDD) or insufficiency (VDI); and (iii) quantify the association between age category, sex, and season types and susceptibility to VDD and VDI, respectively. Laboratory data were collected on serum 25(OH)D levels in children aged between 2 and 18 years (n = 1674) who underwent blood sampling following admission to a university pediatric hospital in Cluj-Napoca (Romania) between January and June 2023. VDD (<20 ng/mL) was observed in 27% of pediatric patients. Among toddlers and preschoolers (2-5 years), VDD was 11%, while it was 33% among school-aged children (6-11 years) and 39% among adolescents (12-18 years). We found a significant difference in the frequencies of vitamin D status between females and males (p = 0.006). Also, we found significant associations of vitamin D status with age categories (p < 0.0001) and seasonal variations (p = 0.03). After adjusting for season of blood collection, the multinomial logistic regression model showed that children aged 6-11 years old (adjusted OR = 7, 95% CI: (4.9, 9.4)), children aged 12-18 years old (adjusted OR = 14, 95% CI: (9.3, 19.6)), and females (adjusted OR = 1.43, 95% CI: (1.10, 1.86)) were significantly associated with higher odds of VDD. In conclusion, the study revealed a significant difference in the frequency of VDD and VDI among pediatric patients older than six years, with a significant difference according to sex and season, being more pronounced among girls and during the winter and spring seasons.

Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline

BACKGROUND

Numerous studies demonstrate associations between serum concentrations of 25-hydroxyvitamin D (25[OH]D) and a variety of common disorders, including musculoskeletal, metabolic, cardiovascular, malignant, autoimmune, and infectious diseases. Although a causal link between serum 25(OH)D concentrations and many disorders has not been clearly established, these associations have led to widespread supplementation with vitamin D and increased laboratory testing for 25(OH)D in the general population. The benefit-risk ratio of this increase in vitamin D use is not clear, and the optimal vitamin D intake and the role of testing for 25(OH)D for disease prevention remain uncertain.

OBJECTIVE

To develop clinical guidelines for the use of vitamin D (cholecalciferol [vitamin D3] or ergocalciferol [vitamin D2]) to lower the risk of disease in individuals without established indications for vitamin D treatment or 25(OH)D testing.

METHODS

A multidisciplinary panel of clinical experts, along with experts in guideline methodology and systematic literature review, identified and prioritized 14 clinically relevant questions related to the use of vitamin D and 25(OH)D testing to lower the risk of disease. The panel prioritized randomized placebo-controlled trials in general populations (without an established indication for vitamin D treatment or 25[OH]D testing), evaluating the effects of empiric vitamin D administration throughout the lifespan, as well as in select conditions (pregnancy and prediabetes). The panel defined "empiric supplementation" as vitamin D intake that (a) exceeds the Dietary Reference Intakes (DRI) and (b) is implemented without testing for 25(OH)D. Systematic reviews queried electronic databases for publications related to these 14 clinical questions. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology was used to assess the certainty of evidence and guide recommendations. The approach incorporated perspectives from a patient representative and considered patient values, costs and resources required, acceptability and feasibility, and impact on health equity of the proposed recommendations. The process to develop this clinical guideline did not use a risk assessment framework and was not designed to replace current DRI for vitamin D.

RESULTS

The panel suggests empiric vitamin D supplementation for children and adolescents aged 1 to 18 years to prevent nutritional rickets and because of its potential to lower the risk of respiratory tract infections; for those aged 75 years and older because of its potential to lower the risk of mortality; for those who are pregnant because of its potential to lower the risk of preeclampsia, intra-uterine mortality, preterm birth, small-for-gestational-age birth, and neonatal mortality; and for those with high-risk prediabetes because of its potential to reduce progression to diabetes. Because the vitamin D doses in the included clinical trials varied considerably and many trial participants were allowed to continue their own vitamin D-containing supplements, the optimal doses for empiric vitamin D supplementation remain unclear for the populations considered. For nonpregnant people older than 50 years for whom vitamin D is indicated, the panel suggests supplementation via daily administration of vitamin D, rather than intermittent use of high doses. The panel suggests against empiric vitamin D supplementation above the current DRI to lower the risk of disease in healthy adults younger than 75 years. No clinical trial evidence was found to support routine screening for 25(OH)D in the general population, nor in those with obesity or dark complexion, and there was no clear evidence defining the optimal target level of 25(OH)D required for disease prevention in the populations considered; thus, the panel suggests against routine 25(OH)D testing in all populations considered. The panel judged that, in most situations, empiric vitamin D supplementation is inexpensive, feasible, acceptable to both healthy individuals and health care professionals, and has no negative effect on health equity.

CONCLUSION

The panel suggests empiric vitamin D for those aged 1 to 18 years and adults over 75 years of age, those who are pregnant, and those with high-risk prediabetes. Due to the scarcity of natural food sources rich in vitamin D, empiric supplementation can be achieved through a combination of fortified foods and supplements that contain vitamin D. Based on the absence of supportive clinical trial evidence, the panel suggests against routine 25(OH)D testing in the absence of established indications. These recommendations are not meant to replace the current DRIs for vitamin D, nor do they apply to people with established indications for vitamin D treatment or 25(OH)D testing. Further research is needed to determine optimal 25(OH)D levels for specific health benefits.

Structural diversification of vitamin D using microbial biotransformations

Vitamin D deficiencies are linked to multiple human diseases. Optimizing its synthesis, physicochemical properties, and delivery systems while minimizing side effects is of clinical relevance and is of great medical and industrial interest. Biotechnological techniques may render new modified forms of vitamin D that may exhibit improved absorption, stability, or targeted physiological effects. Novel modified vitamin D derivatives hold promise for developing future therapeutic approaches and addressing specific health concerns related to vitamin D deficiency or impaired metabolism, such as avoiding hypercalcemic effects. Identifying and engineering key enzymes and biosynthetic pathways involved, as well as developing efficient cultures, are therefore of outmost importance and subject of intense research. Moreover, we elaborate on the critical role that microbial bioconversions might play in the a la carte design, synthesis, and production of novel, more efficient, and safer forms of vitamin D and its analogs. In summary, the novelty of this work resides in the detailed description of the physiological, medical, biochemical, and epidemiological aspects of vitamin D supplementation and the steps towards the enhanced and simplified industrial production of this family of bioactives relying on microbial enzymes. KEY POINTS: • Liver or kidney pathologies may hamper vitamin D biosynthesis • Actinomycetes are able to carry out 1α- or 25-hydroxylation on vitamin D precursors.

Serum Vitamin D and Vaspin Levels Among Patients with Acute Myocardial Infarction and Their Association with Risk Factors

Purpose

The current study investigated and compared serum levels of vitamin D (VD) and vaspin in AMI patients and healthy subjects and correlated these biomarkers with other biochemical risk factors for AMI.

Patients and Methods

The research was carried out at King Abdulaziz University Hospital (KAUH) in Jeddah. Blood samples and additional information were gathered from 110 admitted AMI patients in the Intensive Coronary Care Unit (ICCU) (ages 40-65 years) and 50 adult, healthy volunteers whose BMI and age were similar to those of the patients.

Results

AMI patients had significantly lower vaspin (p < 0.001) and VD levels (p < 0.001) than the control group. Fasting plasma glucose (FPG), hemoglobin A1C (HbA1c), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were shown to be significantly different between AMI patients and controls. Among the AMI patients, 15 (13.6%) had deficient serum VD levels (≤20 ng/mL), 60 (54.5%) had insufficient levels (>20 - <30 ng/mL), and 35 (31.8%) had sufficient levels (≥30 ng/mL). In healthy subjects, VD levels were deficient in 4(8%), insufficient in 13 (26%), and sufficient in 33 (66%). VD insufficiency was more prevalent in AMI patients compared to the healthy group (54.5% vs 26%; p < 0.001). In AMI patients, serum vaspin was found to be related to age and HbA1c in the control group. VD did not show a significant correlation with any variable in AMI patients and healthy subjects. Serum vaspin (p = 0.89) and VD levels (p = 0.29) did not differ significantly between female and male control groups.

Conclusion

Compared to the healthy group, AMI patients showed significantly lower vaspin and VD levels. Additionally, AMI patients had a higher prevalence of VD deficiency and insufficiency, suggesting its possible role in the occurrence of AMI.

The Impact of Vitamin D Deficiency on Gestational Diabetes Mellitus Risk: A Retrospective Study

Background Nowadays, there has been growing attention to vitamin D deficiency's impact on women of reproductive age, both during pregnancy and the preconception period. Because of its possible impact on female reproductive ability, vitamin D deficiency may have multiple implications for maternal and fetal health. Currently, the correlation between vitamin D deficiency and gestational diabetes mellitus (GDM) is gaining attention, mainly due to contradictory findings in the literature. Methods We conducted a single-center, retrospective study involving data from 106 pregnant women to establish a possible link between vitamin D deficiency and GDM risk. We analyzed variables such as vitamin D status, the occurrence of gestational diabetes, and body mass index to identify significant statistical correlations among them. Results Within our study group, the average vitamin D level was 19.5 ± 7.8 ng/mL. Regarding vitamin D status, 59 (55.7%) pregnant women had vitamin D deficiency, 36 (34%) had vitamin D insufficiency, and 11 (10.4%) had optimal vitamin D levels. GDM was diagnosed in 18 cases, representing 17%. After the statistical analysis, we found a positive correlation between gestational diabetes and vitamin D deficiency (chi-square = 4.472, p = 0.049). However, we did not find a significant correlation between gestational diabetes and optimal vitamin D status. Conclusions Pregnant women with vitamin D deficiency are at an increased risk of developing GDM and may benefit from vitamin D supplementation. We believe that further research is necessary to have a comprehensive understanding of vitamin D's effects on pregnancy.

[Translated article] Vitamin D and Skin Cancer: A Controversial Society. Literature Update and Review

Vitamin D (VD) deficiency has been associated with various tumors. However, the association between VD and skin cancer is controversial. Although in non-melanoma skin cancer, adequate or even high levels of VD can be associated with a higher risk of developing tumors, this could be biased by the direct association between sun exposure and VD levels. Regarding melanoma, results are contradictory. Most studies analyzed state that higher levels of VD could reduce the risk of melanoma, be associated with melanomas with better prognosis and with an enhanced antitumor response, and also with fewer adverse events associated with melanoma immunotherapy. However, prospective studies of adequate methodological quality are still needed to assess the association between VD levels and its supplementation and development/prognosis in skin cancer.

Increased loss-of-function filaggrin gene mutation prevalence in atopic dermatitis patients across northern latitudes indicates genetic fitness: A systematic review and meta-analysis

Loss-of-function (LoF) mutations in the filaggrin gene (FLG) constitute the strongest genetic risk for atopic dermatitis (AD). A latitude-dependent difference in the prevalence of LoF FLG mutations was systematically evaluated. A systematic review and meta-analysis were performed to estimate the prevalence of LoF FLG mutations in AD patients and the general population by geography and ethnicity. Risk of bias was assessed by Newcastle-Ottawa Scale and Jadad score. StatsDirect, version 3 software was used to calculate all outcomes. PubMed and EMBASE were searched until 9th December 2021. Studies were included if they contained data on the prevalence of LoF FLG mutations in AD patients or from the general population or associations between AD and LoF FLG mutations and were authored in English. Overall, 248 studies and 229 310 AD patients and individuals of the general population were included in the quantitative analysis. The prevalence of LoF FLG mutations was 19.1% (95% CI, 17.3-21.0) in AD patients and 5.8% (95% CI, 5.3-6.2) in the general population. There was a significant positive association between AD and LoF FLG mutations in all latitudes in the Northern hemisphere, but not in all ethnicities. The prevalence of LoF FLG mutations became gradually more prevalent in populations residing farther north of the Equator but was negligible in Middle Easterners and absent in most African populations. FLG LoF mutations are common and tend to increase with northern latitude, suggesting potential clinical implications for future AD management. The existence of possible genetic fitness from FLG LoF mutations remains unknown.

Alert for the high prevalence of vitamin D deficiency in adolescents in a large Brazilian sample

OBJECTIVE

To estimate the prevalence of vitamin D deficiency and severe deficiency in children and adolescents, in a large Brazilian sample.

METHODOLOGY

Results of 413,988 25(OH)D measurements in children and adolescents aged 0 to 18 years collected between 01/2014 and 10/2018 were obtained from the database of a Clinical Laboratory. In this population, 25 hydroxyvitamin D concentrations below 20 ng/mL are considered deficient, and below 12 ng/mL as severe deficiency. All measurements were performed by immunoassay and the results were distributed by gender, age group, seasonality, and latitude.

RESULTS

The mean of 25(OH)D levels was 29.2 ng/mL with a standard deviation of 9.2 ng/mL. Of the total samples, 0.8% had a concentration < 12 ng/mL, and 12.5% of the samples had a concentration < 20 ng/mL, with a higher prevalence in females. Children under 2 years of age had the lowest prevalence. The effects of latitude and seasonality were quite evident. In samples of female adolescents from the southern region in winter, 36% of vitamin D deficiency and 5% of severe deficiency were found.

CONCLUSION

In this large number of measurements of 25(OH)D in children and adolescents, 12.5% had a deficiency and 0.8% had severe deficiency. A greater deficiency was observed among adolescents, especially females, which raises questions about the need for supplementation during this period of life.

Vitamin D and Skin Cancer: A Controversial Society. Literature Update and Review

Vitamin D (VD) deficiency has been associated with various tumors. However, the association between VD and skin cancer is controversial. Although in non-melanoma skin cancer, adequate or even high levels of VD can be associated with a higher risk of developing tumors, this could be biased by the direct association between sun exposure and VD levels. Regarding melanoma, results are contradictory. Most studies analyzed state that higher levels of VD could reduce the risk of melanoma, be associated with melanomas with better prognosis and with an enhanced antitumor response, and also with fewer adverse events associated with melanoma immunotherapy. However, prospective studies of adequate methodological quality are still needed to assess the association between VD levels and its supplementation and development/prognosis in skin cancer.

Association between Vitamin D Deficiency and Serologic Response to Hepatitis B Virus Vaccination among Heavy Industry Workers

INTRODUCTION

Hepatitis B virus (HBV) vaccination has decreased the overall incidence of HBV infection; however, approximately 5 to 10% of people are non-responders to the vaccination. This study investigated the factors associated with non-response to HBV vaccination, with an emphasis on vitamin D deficiency (VDD).

METHODS

This retrospective observational study focused on adult workers in a single heavy industry. Individuals with negative initial hepatitis B surface antibody (anti-HBs) levels prior to vaccination and who then received a two- or three-dose series of HBV vaccinations were enrolled. The study endpoint was failure to achieve a seroprotective antibody response, defined as an anti-HBs titer less than 10 mIU/mL. Propensity score matching (PSM) and binary logistic regression models were used to adjust the outcomes for other clinical characteristics.

RESULTS

Among 760 workers, 566 (74.5%) exhibited VDD. The non-response rates to HBV vaccination were 13.4% (76/566) and 5.7% (11/194) among workers with and without VDD, respectively (p = 0.005). Even after adjustment using PSM, VDD was still associated with a higher rate of response failure (adjusted odds ratio 2.74; 95% confidence interval 1.40-5.38, p = 0.003). The binary logistic regression model showed that VDD, older age, omission of the third vaccine dose, lower initial anti-HBs titer, and current smoking were associated with response failure.

CONCLUSIONS

Our study suggests that VDD may impair the serologic response following HBV vaccination. Further research is needed to evaluate the effectiveness of vitamin D supplementation in increasing the response to HBV vaccination.

Association between vitamin D insufficiency and depressive symptoms, and functional disability in community-dwelling Brazilian older adults: results from ELSI-Brazil study

Low serum 25(OH)D levels (< 30 nmol/L) have been associated with increased depressive symptom scores over time, and it is believed that functionality may play a mediating role in the relationship between 25(OH)D and depressive symptoms. To comprehend the association between these factors could have significant implications for public health policy. The aim of this study was to verify the association between simultaneous vitamin D insufficiency and depressive symptoms, and functional disability in community-dwelling older adults. This was a cross-sectional study with data from the Brazilian Longitudinal Study of Aging (ELSI-Brazil), collected between 2015 and 2016. The outcomes were functional disability assessed through basic activities of daily living (ADL) and instrumental activities of daily living (IADL). The exposures were vitamin D insufficiency (< 30 nmol/L) and depressive symptoms (≥ 4 points in 8-item version of the Center for Epidemiological Studies-Depression). Crude and adjusted Poisson regression was performed to estimate associations. A total of 1781 community-dwelling older adults included in this study, 14.6% had disability in ADL and 47.9% in IADL; 59.7% had vitamin D insufficient levels, and 33.2% depressive symptoms. The concomitant presence of vitamin D insufficient and depressive symptoms increased the prevalence of ADL by 2.20 (95% CI: 1.25; 3.86) and IADL by 1.54 (95% CI: 1.24; 1.91), respectively. Therefore, preventive strategies to keep older adults physically and socially active, with a good level of vitamin D, are essential to avoid depression and functional disability.

Direct and indirect reference intervals of 25-hydroxyvitamin D: it is not a real vitamin D deficiency pandemic

Introduction

Many studies report vitamin D (25-OH-D) deficiency, although there is no consensus among scientific societies on cut-offs and reference intervals (RI). The aim of this study is to establish and compare RI for serum 25-OH-D by direct and indirect methods.

Materials and methods

Two studies were performed in Zaragoza (Spain). A retrospective study (N = 7222) between January 2017 and April 2019 was used for RI calculation by indirect method and a prospective study (N = 312) with healthy volunteers recruited in August 2019 and February 2020 for direct method. Seasonal differences were investigated. Measurements were performed on Cobas C8000 (Roche-Diagnostics, Basel, Switzerland) using electrochemiluminescence immunoassay technology.

Results

Reference intervals (2.5-97.5 percentile and corresponding 95% confidence intervals, CIs) were as follows: by indirect method 5.6 ng/mL (5.4 to 5.8) - 57.2 ng/mL (55.2 to 59.8), in winter 5.4 ng/mL (5.2 to 5.7) - 55.7 ng/mL (53.6 to 58.4), while in summer 5.9 ng/mL (5.4 to 6.2) - 59.9 ng/mL (56.3 to 62.9). By direct method 9.0 ng/mL (5.7 to 9.5) - 41.4 ng/mL (37.6 to 48.0), in winter 7.4 ng/mL (3.9 to 8.6) - 34.6 ng/mL (30.6 to 51.5), while in summer 13.3 ng/mL (10.1 to 14.1) - 44.1 ng/mL (38.9 to 66.0). In both methods, RIs were higher in summer. A significant difference was observed in 25-OH-D median values between the two methods (P < 0.001).

Conclusions

Reference interval calculation according to the studied area may be a useful tool to adapt the deficiency cut-offs for 25-OH-D. Our data support 25-OH-D values over 12.0 ng/mL for healthy population as sufficient, therefore current recommendations should be updated. In addition, differences in seasonality should be taken into account.

The Relationship Between Vitamin D Intake and Serum 25-hydroxyvitamin D in Young Children: A Meta-Regression to Inform WHO/FAO Vitamin D Intake Recommendations

BACKGROUND

This work was commissioned by the World Health Organization and Food and Agriculture Organization to inform their update on the vitamin D requirements for children aged <4 y.

OBJECTIVES

The objective of this work was to undertake multilevel and multivariable dose-response modeling of serum 25-hydroxyvitamin D (25OHD) to total vitamin D intake in children aged <4 y with the goal of deriving updated vitamin D requirements for young children.

METHODS

Systematically identified randomized controlled trials among healthy children from 2 wk up to 3.9 y of age provided with daily vitamin D supplements or vitamin D-fortified foods were included. Linear and nonlinear random effects multilevel meta-regression models with and without covariates were fitted and compared. Interindividual variability was included by simulating the individual serum 25OHD responses. The percentage of individuals reaching set minimal and maximal serum 25OHD thresholds was calculated and used to derive vitamin D requirements.

RESULTS

A total of 31 trials with 186 data points from North America, Europe, Asia, and Australasia/Oceania, with latitudes ranging from 61°N to 38°S, and with participants of likely mostly light or medium skin pigmentation, were included. In 29 studies the children received vitamin D supplements and in 2 studies the children received vitamin D-fortified milk with or without supplements. The dose-response relationship between vitamin D intake and serum 25OHD was best fitted with the unadjusted quadratic model. Adding additional covariates, such as age, did not significantly improve the model. At a vitamin D intake of 10 μg/d, 97.3% of the individuals were predicted to achieve a minimal serum 25OHD threshold of 28 nmol/L. At a vitamin D intake of 35 μg/d, 1.4% of the individuals predicted to reach a maximal serum 25OHD threshold of 200 nmol/L.

CONCLUSIONS

In conclusion, this paper details the methodological steps taken to derive vitamin D requirements in children aged <4 y, including the addition of an interindividual variability component.

The development of an EU-wide nutrition and physical activity expert knowledge base to support a personalised mobile application across various EU population groups

A healthy lifestyle comprising regular physical activity and an adequate diet is imperative for the prevention of non-communicable diseases such as hypertension and some cancers. Advances in information computer technology offer the opportunity to provide personalised lifestyle advice directly to the individual through devices such as smartphones or tablets. The overall aim of the PROTEIN project (Wilson-Barnes et al., 2021) was to develop a smartphone application that could provide tailored and dynamic nutrition and physical activity advice directly to the individual in real time. However, to create this mobile health (m-health) smartphone application, a knowledge base of reference ranges for macro-/micronutrient intake, anthropometry, biochemical, physiological and sleep parameters was required to underpin the parameters of the recommender systems. Therefore, the principal aim of this emerging research paper is to describe the process by which experts in nutrition and physiology from the PROTEIN consortium collaborated to develop the nutritional and physical activity requirements, based upon existing recommendations, for 10 separate population groups living within the EU including, but not limited to healthy adults, adults with type 2 diabetes mellitus, cardiovascular disease, excess weight, obesity and iron deficiency anaemia. A secondary aim is to describe the development of a library of 24-h meal plans appropriate for the same groups and also encompassing various dietary preferences and allergies. Overall, the consortium devised an extensive nutrition and physical activity knowledge base that is pertinent to 10 separate EU user groups, is available in 7 different languages and is practically implemented via a library of culturally appropriate, 24-h meal plans.

Ambient ultraviolet-B radiation, supplements and other factors interact to impact vitamin D status differently depending on ethnicity: A cross-sectional study

BACKGROUND & AIMS

Many determinants of vitamin D status have been well-described, yet supplementation guidelines largely follow a one-size-for-all model and deficiency remains common. We hypothesised that accounting accurately for ultraviolet-B (UVB) radiation and considering interactions could advance understanding of vitamin D status.

METHODS

Asian, Black, and White participants from the UK Biobank cohort were included (N = 438,978). The Tropospheric Emission Monitoring Internet Service provided UVB data which we linked to participants' place of residence. UVB dose over 135 days prior to blood draw was weighted and added, yielding cumulative and weighted UVB (CW-D-UVB). The association between 25(OH)D and selected variables was assessed in multivariable linear regression models with and without interactions, stratified by ethnicity. Predictors were ranked using standardised β-coefficients.

RESULTS

Median 25(OH)D differed by ethnicity (Asian: 25.4 nmol/L (10.2 ng/mL), Black: 30.6 nmol/L (12.2 ng/mL), White: 47.9 nmol/L (19.2 ng/mL), p-value < 0.001). CW-D-UVB was strongly associated with 25(OH)D in all ethnicities. It was the most important predictor in White (βAsian = 0.15, βBlack = 0.20, βWhite = 0.35), whereas supplementation was in Asian and Black participants (βAsian = 0.30, βBlack = 0.24, βWhite = 0.21). We identified statistically significant interactions between BMI:supplementation (all), CW-D-UVB:sex (Asian and White), and CW-D-UVB:age (Black and White), and in White population between CW-D-UVB and supplementation, BMI, and cholesterol.

CONCLUSION

Vitamin D deficiency was widespread, particularly among non-White individuals. UVB was a strong predictor of 25(OH)D and the effect was modified by other factors. Findings suggest that accurately measured ambient-UVB radiation and interactions could improve 25(OH)D prediction models, and support personalised approaches to vitamin D optimisation.

LLL 44 - 2 - Micronutrients in clinical nutrition: Vitamins

Vitamins are essential organic molecules, which are required in the diet in relatively small amounts in any form of nutrition (oral, enteral, parenteral). Despite the small amounts that are required, the vitamins are essential both for maintenance of health, growth, and treatment of disease. After reminding about the principal function of all the vitamins, their needs and the clinical consequences of their deficit, the text present some common clinical problems: the impact of inflammation on the assessment of status. The reasons and diseases which cause increased requirements are presented, with the indications to monitoring of blood levels which remain the classical way to assess status in clinical settings. The text summarises the most relevant clinical manifestations of vitamins depletion and deficiency, the difficulties in assessing status, and makes recommendations for provision for medical nutrition therapy.

Nutritional Challenges in Nursing Homes: Pilot Study on Macronutrient Intake and Status of Vitamins D and B12

Older adults living in nursing homes (NH) are considered a population group that could be at risk in terms of nutrition, even more so than their community-dwelling peers. Evidence on the nutritional status of NH residents is scarce, as they are commonly excluded from population-based dietary studies. This is also the case in Slovenia. In the presented pilot study, we assessed the intake of macronutrients as well as the intake and status of vitamin D and vitamin B12 on a sample of NH and NH daycare center users to explore the need for a larger representative study. The pilot study included 37 participants from three Slovenian NH (20 participants) and their daycare centers (17 participants). Daycare centers offer daytime care services for older adults, where users are also provided with major meals during their stay. Intakes of energy and nutrients were estimated by three 24 h dietary records. Fasting blood samples were collected for the assessment of vitamin D and vitamin B12 status. Over 90% of the participants had daily energy and protein intakes below recommendations (reference values: energy intake: males 2100 kcal and females 1700 kcal; protein intake > 1 g/kg body mass). The males' median daily intakes of vitamin D were 1.7 µg (1.5 µg females), and 2.3 µg for vitamin B12 (2.0 µg females). None of the participants had adequate vitamin D intake (>20 µg), and 92.3% males and 87.5% females had inadequate vitamin B12 intake (<4 µg). The prevalence of vitamin D deficiency (serum 25-OH-D conc. < 30 nmol/L) was 100% among NH residents and 53% among NH daycare center users. The prevalence of vitamin B12 deficiency was found in 20% of NH residents. The study results highlighted that certain nutrients might be critical in this population, especially among NH residents; however, a more thorough investigation with the inclusion of other important markers of nutritional status should be performed on a larger, representative sample to support the development and implementation of appropriate public health interventions.

Globally Estimated UVB Exposure Times Required to Maintain Sufficiency in Vitamin D Levels

A paucity of vitamin D is a common deficiency globally, with implications for many aspects of health besides the well-known impact on musculoskeletal health. The two sources of vitamin D are through oral intake, or through endogenous synthesis in the skin when exposed to ultraviolet radiation in sunlight. Assessing nutritional needs, whether by food, food fortification or supplementation, is aided by an understanding of local potential for cutaneous synthesis of the vitamin, dependent on latitude and climate, personal skin type and local culture. To aid these discussions we provide indicative exposure times for the maintenance of vitamin D status as a function of latitude, month and skin type, for the clear-sky case and all-sky conditions, for an ambulatory person wearing modest skirt/shorts and T-shirt. At latitudes greater than ±40 degrees, lack of available sunlight limits vitamin D synthesis in some months for all, while at the equator exposure times range from 3 to 15 min at noontime, for white and black skin, respectively. Rather than a sun exposure prescription, the data are intended to show where nutritional vitamin D intake is necessary, advisable, or can be mitigated by sun exposure, and allows for such advice to be personalized to account for different sub-groups in a multicultural population.

The Inverted U-Shaped Association between Serum Vitamin D and Serum Uric Acid Status in Children and Adolescents: A Large Cross-Sectional and Longitudinal Analysis

BACKGROUND

Serum vitamin D is associated with hyperuricemia. However, previous studies have been controversial, with limited focus on children and adolescents.

OBJECTIVE

This study aimed to examine the cross-sectional and longitudinal associations between serum vitamin D and serum uric acid (SUA) levels in children and adolescents.

METHODS

The cross-sectional survey comprised 4777 participants aged 6 to 18 years, while the longitudinal survey involved 1641 participants aged 6 to 12 years, all derived from an ongoing cohort study in Shenzhen, China. Restricted cubic splines were used to visualize the dose-response relationship between vitamin D and SUA and the risk of higher SUA status. Two-segment generalized linear models (GLM) and logistic models were used to assess the association between vitamin D and SUA and higher SUA status, respectively. The longitudinal analysis used GLM.

RESULTS

We observed an inverted U-shaped relationship between vitamin D and SUA (p-overall < 0.0001, p-nonlinear = 0.0002), as well as the risk of higher SUA status (p-overall = 0.0054, p-nonlinear = 0.0015), with the vitamin D inflection point at 24.31 and 21.29 ng/mL, respectively. A 10 ng/mL increment in 25(OH)D3 levels, when below 20.92 ng/mL, was associated with a 68% rise in the risk of higher SUA status (OR: 1.68, 95%CI: 1.07-2.66). Conversely, when 25(OH)D3 levels were above or equal to 20.92 ng/mL, a 10 ng/mL increment was associated with a 45% reduction risk of higher SUA status (OR: 0.55, 95%CI: 0.36-0.84). Longitudinal analysis indicated that the annual change of SUA was from -4.80 (β, 95%CI: -10.74, 1.13) to -9.00 (β, 95%CI: -15.03, -2.99) and then to -6.77 (β, 95%CI: -12.83, -0.71, p for trend = 0.0212) μmol/L when increasing the quartile of vitamin D3.

CONCLUSIONS

An inverse U-shaped relationship was observed between vitamin D and SUA as well as the risk of higher SUA status. Sufficient vitamin D levels appear to play a preventative role against the age-related increase in SUA. Ensuring adequate vitamin D levels may be beneficial in improving uric acid metabolism.

Vitamin D: A Bridge between Kidney and Heart

Chronic kidney disease (CKD) and cardiovascular disease (CVD) are highly prevalent conditions, each significantly contributing to the global burden of morbidity and mortality. CVD and CKD share a great number of common risk factors, such as hypertension, diabetes, obesity, and smoking, among others. Their relationship extends beyond these factors, encompassing intricate interplay between the two systems. Within this complex network of pathophysiological processes, vitamin D has emerged as a potential linchpin, exerting influence over diverse physiological pathways implicated in both CKD and CVD. In recent years, scientific exploration has unveiled a close connection between these two prevalent conditions and vitamin D, a crucial hormone traditionally recognized for its role in bone health. This article aims to provide an extensive review of vitamin D's multifaceted and expanding actions concerning its involvement in CKD and CVD.

Vitamin D fortification of foods - sensory, acceptability, cost, and public acceptance considerations

In terms of vitamin D food fortification, there are a number of important considerations in relation to selection of the food vehicle and fortificant. While there has been much research focus on the ability of fortified foods to improve vitamin D status, other considerations, such as sensory properties and acceptability, cost, and public attitudes around vitamin D-fortified foods, have received less attention. Thus, the present narrative review aimed to summarize the existing knowledge around these important considerations. In summary, its findings suggest that: i) vitamin D addition to various food vehicles, at levels consistent with the supply of part or all the recommended intake, does not alter their sensory characteristics or overall acceptability; ii) overall, vitamin D fortification of foods is relatively cost-effective, despite the fact that some attitudinal studies highlighted participant concerns about the potential cost/expense of vitamin D-fortified foods; iii) evidence from various attitudinal studies suggest a high level of acceptance and/or purchase intention (i.e., extent to which customers are willing and inclined to buy) of vitamin D-fortified food products by the general public; and iv) there have been repeated calls for vitamin D public health educational/information campaigns to help educate consumers about the health risks associated with vitamin D deficiency and nutritional benefits associated with consumption of vitamin D-fortified foods. Such campaigns could positively mediate attitudes and acceptance of vitamin D-fortified foods amongst the public, and could also help address misconceptions and allay fears around vitamin D for concerned individuals. Lastly, the findings of the present review also highlight the existence of between-country differences, even within Europe, in relation to attitudes and purchase intention of vitamin D-fortified foods and the perceived appropriateness of certain food vehicles for vitamin D fortification, as well as the best mix of communication channels for a vitamin D public health educational/information campaign.

Seasonal Variation in Vitamin D Status Does Not Interfere with Improvements in Aerobic and Muscular Endurance in Conscripts during Basic Military Training

Considering a lack of respective data, the primary objective of this study was to assess whether seasonal variation in vitamin D status (D-status) affects the extent of improvement in physical performance (PP) in conscripts during basic military training (BMT). D-status, PP and several blood parameters were measured repeatedly in conscripts whose 10-week BMT started in July (cohort S-C; n = 96) or in October (cohort A-C; n = 107). D-status during BMT was higher in S-C compared to A-C (overall serum 25(OH)D 61.4 ± 16.1 and 48.5 ± 20.7 nmol/L, respectively; p < 0.0001). Significant (p < 0.05) improvements in both aerobic and muscular endurance occurred in both cohorts during BMT. Pooled data of the two cohorts revealed a highly reliable (p = 0.000) but weak (R2 = 0.038-0.162) positive association between D-status and PP measures both at the beginning and end of BMT. However, further analysis showed that such a relationship occurred only in conscripts with insufficient or deficient D-status, but not in their vitamin D-sufficient companions. Significant (p < 0.05) increases in serum testosterone-to-cortisol ratio and decreases in ferritin levels occurred during BMT. In conclusion, a positive association exists between D-status and PP measures, but seasonal variation in D-status does not influence the extent of improvement in PP in conscripts during BMT.

Association between vitamin D deficiency and benign paroxysmal positional vertigo (BPPV) incidence and recurrence: a systematic review and meta-analysis

OBJECTIVES

The objective of this study is to determine the relationship between serum vitamin D level and the risk of developing benign paroxysmal positional vertigo (BPPV) incidence and recurrence in countries in the Northern Hemisphere.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Scopus and Web of Science databases were searched for studies published between January 2000 and February 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Participants located in the Northern Hemisphere aged 18 or over with at least one episode of BPPV, serum 25-hydroxyvitamin D levels measured and reported, no comorbidities or history of vitamin D supplementation.

DATA EXTRACTION AND SYNTHESIS

Data extraction and synthesis were performed by a single reviewer and checked by a second reviewer. Inclusion and exclusion criteria and risk of bias were assessed by two independent reviewers using the Newcastle Ottawa Tool for Cohort studies and Risk of Bias Assessment Tool for Nonrandomised Studies checklist for case-control studies. Meta-analysis was conducted using random effects models. Standard mean difference with a 95% CI was used to measure the relationship between vitamin D level and BPPV.

RESULTS

The 35 articles identified by the literature search reported data of 9843 individuals. 19 studies (7387 individuals) were included in the BPPV incidence meta-analysis while 7 studies (622 individuals) were included in the BPPV recurrence meta-analysis. Lower serum vitamin D levels were found in BPPV incidence compared with controls, but the relationship between vitamin D levels in recurrent BPPV compared with non-recurrent disease remained uncertain.

CONCLUSION

Results of this systematic review and meta-analysis demonstrated a negative correlation between serum vitamin D and BPPV incidence, while any relationship between serum vitamin D and BPPV recurrence remained uncertain. Risk of bias analysis revealed evidence of variable quality. There were insufficient data available to evaluate seasonal relationships between serum vitamin D and BPPV. Given the potential for this as a confounding factor, future research should aim to investigate this further.

PROSPERO REGISTRATION NUMBER

CRD42021271840.

Associations between vitamin D status, VDR gene polymorphisms and echocardiographic markers in Polish patients with cardiovascular disease

Aim: This work was designed to investigate the associations between vitamin D metabolites, VDR gene polymorphisms and echocardiographic markers in a population of patients with cardiovascular disease. Methods: Echocardiographic markers for 42 patients were determined with tissue Doppler techniques. PCR-restriction fragment length polymorphism analysis identified genetic variants ApaI, TaqI, BsmI and FokI. A validated UHPLC-MS/MS method determined vitamin D metabolites. Results: Patients with the ApaI-GT genotype exhibited a lower pressure gradient across the aortic valve than ApaI-TT carriers. BMI, ApaI-GT, TaqI-TC, aortic arch diameter and maximal pressure gradient were significant univariate predictors of hypertension. Conclusion: A potential link exists between VDR gene polymorphisms and cardiovascular function.

Self-reported prescribing behaviour of vitamin D prophylaxis in healthy children by Belgian paediatricians

There is currently no consensus on the guidelines for vitamin D prophylaxis in healthy children. The purpose of this study was to investigate the prescribing behaviour of vitamin D prophylaxis among Belgian paediatricians. Between June and September 2022, a questionnaire was distributed by email to all Belgian paediatricians who are a member of at least one of three scientific or professional organisations, as well as to the heads of every Belgian paediatric or neonatal hospital ward. We analysed 426 completed questionnaires. All regions, age categories and subspecialties were represented. Vitamin D prophylaxis is always or frequently recommended by 98% of paediatricians. Fifty-eight per cent of paediatricians advise vitamin D prophylaxis up to the age of six years and 66% of paediatricians advise a daily dose of 400 IU. In nearly every hospital in Belgium (96%), there is a specific protocol for vitamin D prophylaxis for newborns; but not for the paediatric unit (only 30%). Nearly all Belgian paediatricians prescribe vitamin D prophylaxis to infants. Although not recommended by guidelines, 25(OH)D is frequently measured by paediatricians. Practices regarding duration and dosing of vitamin D prophylaxis show large variability. Most neonatal wards do have a protocol, whereas most paediatric wards do not.

Evolution and impact of Standard Reference Materials (SRMs) for determining vitamin D metabolites

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health, Office of Dietary Supplements (NIH ODS), introduced the first Standard Reference Material® (SRM) for determining vitamin D metabolites in 2009 motivated by significant concerns about the comparability and accuracy of different assays to assess vitamin D status. After 14 years, a suite of five serum matrix SRMs and three calibration solution SRMs are available. Values were also assigned for vitamin D metabolites in five additional SRMs intended primarily to support measurements of other clinical diagnostic markers. Both the SRMs and the certification approach have evolved from significant exogenous serum content to primarily endogenous content and from value assignment by combining the results of multiple analytical methods to the use of measurements exclusively from reference measurement procedures (RMPs). The impact of the availability of these SRMs can be assessed by both the distribution information (sales) and by reports in the scientific literature describing their use for method validation, quality control, and research. In this review, we describe the development of these SRMs, the evolution in design and value assignment, the expansion of information reported, and SRM use in validating analytical methods and providing quality assurance within the vitamin D measurement community.

Association between vitamin D status, physical performance, sex, and lifestyle factors: a cross-sectional study of community-dwelling Kosovar adults aged 40 years and older

PURPOSE

Vitamin D status and its association with age-related decline in physical performance and strength have already been highlighted in various ways, but data on the situation in developing countries are scarce. This study aimed to investigate vitamin D status, its association with muscle mass and function, and other potential determinants such as age, sex, lifestyle factors (physical activity, dietary behavior), self-perceived health status, medication intake, education and financial situation in adults from Kosovo.

METHODS

This cross-sectional study included 297 participants (54.5% women), aged ≥ 40 years. Serum 25-hydroxyvitamin D (25(OH)D) concentration, hand grip strength and physical performance tests, body composition, vitamin D dietary intake and knowledge were assessed. The interaction between serum 25(OH)D status, lifestyle factors and muscle traits was investigated.

RESULTS

Vitamin D deficiency (< 50 nmol/L) was observed in 47.5% of the total population, of whom 14.7% of them were severely deficient (< 30 nmol/L). No associations were found between 25(OH)D concentration and age. Daily dietary intake of vitamin D was low (1.89 ± 0.67 µg) and 87.6% of individuals did not take vitamin D supplements. However, vitamin D supplementation was the only variable that added statistical significance (p < 0.05) to the prediction of vitamin D status (3.8%). On the other hand, age, medication intake and vitamin D level contributed significantly to the overall regression model, explaining 24.9% of the 30-s chair stand performance as an indicator of lower-body strength endurance.

CONCLUSION

Vitamin D deficiency is highly prevalent among community-dwelling adults in Kosovo and low serum 25(OH)D has been associated with low muscle strength. This implies an urgent need for the development of comprehensive prevention strategies, focusing on pharmacological (supplementation) but also on non-pharmacological strategies such as education, food fortification or lifestyle advices.