Vitamin D status in the adult population of Bursa-Turkey

Biological variation of plasma 25-Hydroxyvitamin D3, Serum vitamin B12, folate and ferritin in Turkish healthy subject

Biological variation (BV) plays a crucial role in determining analytical performance specifications, assessing serial measurements of individuals, and establishing the use of population-based reference intervals. Our study aimed to calculate the BV and BV-based quality goals of 25-hydroxyvitamin D3 (25-OH D3), ferritin, folate and vitamin B12 tests. We included a total of 22 apparently healthy volunteers (9 women and 13 men) aged 18-55 years in the study that we conducted in Turkey. Blood samples were collected from the participants once a week for five weeks. Serum ferritin, folate and vitamin B12 levels were measured using immunochemical method, while plasma 25-OH D3 levels were determined using the high-performance liquid chromatography method. Analysis of variance (ANOVA) was used to estimate analytical variation(CVA), within-subject BV(CVI) and between-subject BV(CVG). The individuality index (II) and reference change value (RCV) were calculated based on these data. The CVI of 25-OH D3, ferritin, folate, and vitamin B12 were found to be 1.8% (0.6%-2.5%), 16.9% (14.4%-20.2%), 10.7% (9.2%-12.7%), and 8.6% (6.8%-10.5%), respectively. CVG were 44.2% (34.3%-69.9%), 132% (87.7%-238%), 19.4% (14.4%-28.8%), and 39.6% (29.8%-59.0%) for the same biomarkers, while CVA were 3.2% (2.81%-3.71%), 3.5% (3.1%-4.1%), 4.0% (3.5%-4.6%), and 7.5% (6.6%-8.6%), respectively. The II values for 25-OH D3, ferritin, folate, and vitamin B12 were calculated as 0.04, 0.13, 0.55, and 0.22, respectively. The RCV were 10.2%, 47.8%, 31.7%, and 31.6%, respectively. Because the tests analyzed in this study exhibit high individuality, RCV should be preferred rather than population-based reference ranges in clinical interpretation of results.

Difference in Levels of Vitamin D between Indoor and Outdoor Athletes: A Systematic Review and Meta-Analysis

Vitamin D, its importance in different processes taking place in the human body, the effects of abnormal levels of this hormone, either too low or too high, and the need for supplementation have been extensively researched thus far. Variances in exposure to sunlight can cause vitamin D levels to fluctuate. Indoor activity can be a factor for these fluctuations and can lead to a decrease in vitamin D levels. We conducted a systematic review and meta-analysis aiming to identify whether indoor compared to outdoor training has a significant influence on vitamin D levels; we also performed subgroup analyses and multivariate meta-regression. The type of training has an impact on vitamin D levels that is influenced by multiple cofounders. In a subgroup analysis not considering cofounders, the mean serum vitamin D was 3.73 ng/mL higher in outdoor athletes, a difference which barely fails to achieve significance (p = 0.052, a total sample size of 5150). The indoor-outdoor difference is only significant (clinically and statistically) when considering studies performed exclusively on Asian athletes (a mean difference of 9.85 ng/mL, p < 0.01, and a total sample size of 303). When performing the analyses within each season, no significant differences are observed between indoor and outdoor athletes. To control for multiple cofounders (the season, latitude, and Asian/Caucasian race) simultaneously, we constructed a multivariate meta-regression model, which estimated a serum vitamin D concentration lower by 4.446 ng/mL in indoor athletes. While a multivariate model suggests that outdoor training is associated with slightly higher vitamin D concentrations when controlling for the season, latitude, and Asian/Caucasian race, the type of training has a numerically and clinically small impact. This suggests that vitamin D levels and the need for supplementation should not be decided based on training type alone.

Comparison of Serum Vitamin D Levels with Glucose, Lipid, and the Other Biochemical Parameters: A Cross-Sectional Study

"Since vitamin D is synthesized from cholesterol, it is claimed to be associated with insulin resistance, suggesting that there may be an association between vitamin D glucose and lipids. For this reason, we aimed to investigate a relationship between vitamin D and biochemical parameters, including glucose and lipids. This cross-sectional study included 198 patients .admitted to the family medicine outpatient clinic between June and December 2016. There was no significant correlation between vitamin D and serum glucose, total cholesterol, triglyceride, HDL cholesterol, LDL cholesterol, calcium, magnesium, sodium, TSH, and body mass index values in both men and women. There was a correlation between vitamin D and total cholesterol and LDL cholesterol levels in the younger subjects below 41 years (p=0.002). Regression analysis with other variables showed no statistical significance between vitamin D levels on LDL-C levels (P=0.309). Despite previous studies, our study did not confirm the effects of vitamin D on serum glucose, lipid, calcium, and other biochemical parameters. However, these results suggest that the standard up-to-date literature showing the relationship between vitamin D and various metabolic and hormonal disorders may need to be confirmed by new large-scale studies. "

Multifactorial hypovitaminosis D among women in the South-East Oases of Morocco

This study assessed the vitamin D status among women in South-East Oases of Morocco. Two hundred thirty-three healthy volunteer women were recruited at five urban and rural health centers. Hypovitaminosis D is very common in this region and correlated to age, monthly income, skin color, daily sun exposure, BMI, and body fat percentage.

PURPOSE

This study assessed the vitamin D status among women in the Draa-Tafilalet region and its relationship with clinical, anthropometric, and behavioral parameters.

METHODS

The study was carried out with 233 women in consultation at five urban and rural health centers in the South-East region of Morocco. The data collected relate to age, monthly income, educational level, BMI, body fat percentage, daily sun exposure, physical activity level, veil wear, and skin color. The plasma determination of vitamin D was measured by immunofluorescence. Statistical analyses were performed using Python and Jamovi.

RESULTS

The median 25(OH)D plasma concentration was 9.95 ng/mL (IQR: 8-13.18). A total of 50.64% of women had 25(OH)D levels below 10 ng/ml and 47.21% had levels between 10 and 30 ng/mL. Statistical tests showed an association between hydroxyvitamin D plasma levels and age (r =  - 0.139; p = 0.034), monthly income (p = 0.001), BMI (r =  - 0.200; p = 0.002), body fat percentage (r =  - 0.131; p = 0.049), daily sun exposure (r = 0.165; p = 0.012), and skin color (p < 0.001). Binomial logistic regression showed that darker skin was associated with vitamin D deficiency (< 10 ng/mL). It also showed that high income and longer sun exposure could be protecting factors against vitamin D deficiency.

CONCLUSION

The plasma concentrations of vitamin D in women in the Draa-Tafilalet region were low compared to expected results for a high sunshine time area.

Low bone mineral density and its related factors in adults with congenital heart disease in Vietnam: A cross-sectional study

Background and Aims

Recent studies have highlighted the increased risk of low bone mineral density (BMD) in adults with cardiovascular disease. However, little is known about BMD in adults with congenital heart disease (CHD), particularly in developing countries. We hypothesized that factors related to BMD would lead to a high prevalence of low BMD in adults with CHD. This study aimed to determine the prevalence of low BMD and its related factors in Vietnamese adults with CHD.

Methods

We conducted a cross-sectional study of 73 adults diagnosed with CHD in Vietnam. Low BMD was classified based on their site-specific Z-scores and T-scores at the posteroanterior lumbar spine and left proximal femur. Logistic regression analyses were performed to evaluate factors related to low BMD.

Results

Low BMD was confirmed in one-third of the adults with CHD. There were trends of more bone loss in certain parts of the body than in others, with the prevalence of low BMD at the sites of the lumbar vertebrae (L1‒L4) and left proximal femur (femoral neck, trochanteric femur, and intertrochanteric area) of 43.9%, 31.8%, 28.8%, 33.3%, 8.8%, 1.5%, and 6.1%, respectively. The prevalence of low BMD in the lumbar spine was significantly higher than that in the left proximal femur (34.3% vs. 2.9%, p < 0.001). Moreover, the prevalence of low BMD was significantly higher in adults with CHD than in those without polycythemia and vitamin D deficiency (55.6% vs. 20.9%, p = 0.001 and 46.2% vs. 19.4%, p = 0.002, respectively). A stratified multivariate logistic regression analysis revealed that low BMD was associated with polycythemia (odds ratio: 4.72; 95% confidence interval: 1.64-13.58, p = 0.004).

Conclusions

Low BMD is common among adults with CHD in Vietnam and related to polycythemia.

Low Vitamin D Status is Not Associated with the Aggressive Pathological Features of Papillary Thyroid Cancer

Objectives:

In the present study, we investigated the effects of Vitamin D (vit D) deficiency on aggressiveness of papillary thyroid cancer (PTC).

Methods:

Patients with PTC confirmed with pathological examination, whom were operated by a single surgeon between 2012 and 2017, were included in the study. The data of the patients were analyzed retrospectively. Cancers other than PTC, patients with hyperthyroidism and/or using antithyroid drugs were excluded from the study. The patients were classified as four quartiles according to serum Vit D levels; category 1 (<7.1 ng/mL), category 2 (7.2–11.8 ng/mL), category 3 (11.9–23.4 ng/mL) and category 4 (>23.5 ng/mL).

Results:

A total of 133 patients (103 female, 30 male) with mean age of 46.4±13.6 (17–82) years were included in the study. There was no significant difference between the categories in terms of preoperative Vit D values according to the evaluated tumor aggressiveness characteristics. It was determined that the presence of tumor with a size above 1 cm and T3/4 tumor were not affected by Vit D level. There was no significant difference between Vit D categories regarding the characteristics of aggressiveness such as multicentricity, lymphovascular invasion, central, and lateral metastases.

Conclusion:

According to our results, serum Vit D levels are not associated with the aggressive tumor characteristics of PTC.

Interaction between Dietary Fat Intake and Metabolic Genetic Risk Score on 25-Hydroxyvitamin D Concentrations in a Turkish Adult Population

Previous studies have pointed out a link between vitamin D status and metabolic traits, however, consistent evidence has not been provided yet. This cross-sectional study has used a nutrigenetic approach to investigate the interaction between metabolic-genetic risk score (GRS) and dietary intake on serum 25-hydroxyvitamin D [25(OH)D] concentrations in 396 unrelated Turkish adults, aged 24-50 years. Serum 25(OH)D concentration was significantly lower in those with a metabolic-GRS ≥ 1 risk allele than those with a metabolic-GRS < 1 risk allele (p = 0.020). A significant interaction between metabolic-GRS and dietary fat intake (energy%) on serum 25(OH)D levels was identified (Pinteraction = 0.040). Participants carrying a metabolic-GRS ≥ 1 risk allele and consuming a high fat diet (≥38% of energy = 122.3 ± 52.51 g/day) had significantly lower serum 25(OH)D concentration (p = 0.006) in comparison to those consuming a low-fat diet (<38% of energy = 82.5 ± 37.36 g/d). In conclusion, our study suggests a novel interaction between metabolic-GRS and dietary fat intake on serum 25(OH)D level, which emphasises that following the current dietary fat intake recommendation (<35% total fat) could be important in reducing the prevalence of vitamin D deficiency in this Turkish population. Nevertheless, further larger studies are needed to verify this interaction, before implementing personalized dietary recommendations for the maintenance of optimal vitamin D status.

Impact of vitamin D deficiency on COVID-19

Background & aims

COVID-19 has emerged as a global pandemic affecting millions of people. Vitamin D deficiency is one of the risk factors for increased susceptibility to COVID-19. This study aimed to examine the correlation between the prevalence of vitamin D deficiency and COVID-19 infection and mortality rates among the adult population in European and Asian continents.

Methods

Prevalence of vitamin D deficiency in each country was retrieved through literature searching on PubMed® database for the last ten years. As of December, 31^st 2020, COVID-19 infections and mortalities per million population were extracted from the ‘real time’ statistics of the Worldometer website. The association between both vitamin D deficiency and COVID-19 infections and mortalities were explored.

Results

Forty seven countries were included in the analysis. The prevalence of vitamin D deficiency ranged from 6.9 to 81.8% in European countries and 2.0–87.5% in Asian countries. Significantly positive correlations were observed for both COVID-19 infection (r = 0.76; p < 0.001) and mortality rates (r = 0.75; p < 0.001) in the Asian continent. The correlation values for the infections and mortality rates in the European continent were (r = 0.37; p = 0.08) and (r = 0.43; p = 0.04) respectively. When both the continents were combined, the correlation results for both infection (r = 0.42; p = 0.003) and mortality (r = 0.35; p = 0.016) rates with vitamin D deficiency values remained significant.

Conclusion

Prevalence of vitamin D deficiency was significantly associated with the mortality rate of COVID-19 in Europe and Asia. The association between the infection rate and prevalence of vitamin D deficiency was significant for Asia only. Both the associations were significant when the two continents were combined in the analysis. Therefore we suggest that vitamin D supplementation could play a key role in the prevention and/or treatment of the COVID-19 patients.

Impact of the vitamin D deficiency on COVID-19 infection and mortality in Asian countries

BACKGROUND AND AIMS

COVID-19 is a pandemic that has affected beyond 100 million and caused nearly 3 million deaths globally. Vitamin D is a known risk factor for COVID-19. Therefore, we aimed to investigate the association of prevalence of vitamin D deficiency and mean vitamin D level with COVID-19 infection and mortality in Asia, predicting with other confounding factors such as median age, obesity, and diabetes.

METHODS

COVID-19 infections and mortalities among the Asian countries were retrieved from the Worldometer website. Information on prevalence of vitamin D deficiency and mean vitamin D values in each Asian country was retrieved through literature searching on PubMed® and Google scholar. The associations between COVID-19 infections and mortalities with prevalence of vitamin D deficiency and mean vitamin D level were explored with correlation coefficients. As a predictive analysis, multiple linear regression was carried out with all confounders.

RESULTS

Positive correlations were observed for prevalence of vitamin D deficiency with COVID-19 infections (r = 0.55; p = 0.01; R2 = 0.31) and mortalities (r = 0.50; p = 0.01; R2 = 0.25). Moreover, the associations for the COVID-19 infections and mortalities improved to r = 0.76 (p = 0.002; R2 = 0.58) and r = 0.65 (p = 0.03; R2 = 0.42), respectively, after predicting with confounding factors. Similarly, mean vitamin D level had a significant negative correlation with COVID-19 infections (r = -0.77; p = 0.04; R2 = 0.59) and mortalities (r = -0.80; p = 0.03; R2 = 0.63) when combining with confounders.

CONCLUSION

Prevalence of vitamin D deficiency is significantly positively associated whereas the mean vitamin D level is significantly negatively associated with both infection and mortality rate of COVID-19 among Asian countries upon predicting with all confounders.