Vitamin D and health in the Mediterranean countries

Paradoxical suboptimal vitamin D levels in a Mediterranean area: a population-based study

Policies in sunny countries, such as those in the Mediterranean area, do not promote vitamin D supplementation despite some studies might suggest the high prevalence of sub-optimal levels. The objective was to determine the vitamin D levels by 25-hydroxyvitamin D (25(OH)D) of a Mediterranean population and their characteristics. This population-based study included a database of public health system from all individuals living in Catalonia > 18 years who had some measure of 25(OH)D between January 2018 and April 2021. More than half million people were classified based on 25(OH)D measurements to study their characteristics. Three vitamin D categories were created: < 20 ng/ml deficiency, 20-30 ng/ml insufficiency and > 30 ng/ml optimal. Less than 10% of the population residing in Catalonia had recent 25(OH)D determinations and the majority of determinations were in ≥ 45 years and in women. Around 80% of young people with determination had sub-optimal levels but the prevalence of vitamin D supplementation prescription increased with age which was associated with better values of 25(OH)D. In a Mediterranean area 25(OH)D determinations were low despite the high prevalence of suboptimal levels in the population with recent determination. In addition, the measurements were especially concentrated in people ≥ 45 years of age and in women who were, in addition, the groups to whom the most vitamin D supplementation was prescribed. On the contrary, young people presented few determinations of 25(OH)D and, although majority of them showed sub-optimal levels, vitamin D supplementation was not prescribed in most cases.

Association of sunshine duration with acute myocardial infarction hospital admissions in Beijing, China: A time-series analysis within-summer

BACKGROUND

Over the years, various epidemiological studies found that acute myocardial infarction (AMI) often shows seasonal rhythm patterning, which is usually influenced by the variations of environmental factors, such as air pollution, ambient temperature, solar activity, relative humidity. However, there are few studies on the impact of sunlight-induced AMI especially in developing countries, and they had inconsistent results. This study aimed to examine within-summer variations in the temporal association between sun exposure and AMI.

METHODS

We obtained hospitalization data for AMI of Beijing during 2013-2019. We used a distributed lag non-linear model (DLNM) combined with a quasi-Poisson regression model to estimate the non-linear lag effects of sunshine duration on AMI incidences. We evaluated the overall effect of AMI admissions with exposure to sunshine duration in the lag 0-21 days.

RESULTS

A total of 45,301 AMI cases were enrolled in our study during summer (June-September). The minimum of the morbidity was during days with a sunshine duration of 3.9 h. We found significant and U-shaped associations between sunshine duration and AMI, and the overall estimated relative risk was 1.29 (95% CI: 1.02,1.62) and 1.69 (95% CI: 1.28,2.24) for short (1st percentile) and long (99th percentile) sunshine duration, respectively. The males and younger people (<65 years) were most susceptible to these effects.

CONCLUSION

Our results suggest that both short and long sunshine duration could increase the risk of AMI admissions, especially for males and younger people. We suggest that public health policymakers should fully consider the balance of the pros and cons of solar exposure, and provide appropriate public health recommendations accordingly to gain the greatest benefits from sunlight.

Calcifediol for Use in Treatment of Respiratory Disease

Calcifediol is the prohormone of the vitamin D endocrine system (VDES). It requires hydroxylation to move to 1,25(OH)2D3 or calcitriol, the active form that exerts its functions by activating the vitamin D receptor (VDR) that is expressed in many organs, including the lungs. Due to its rapid oral absorption and because it does not require first hepatic hydroxylation, it is a good option to replace the prevalent deficiency of vitamin D (25 hydroxyvitamin D; 25OHD), to which patients with respiratory pathologies are no strangers. Correcting 25OHD deficiency can decrease the risk of upper respiratory infections and thus improve asthma and COPD control. The same happens with other respiratory pathologies and, in particular, COVID-19. Calcifediol may be a good option for raising 25OHD serum levels quickly because the profile of inflammatory cytokines exhibited by patients with inflammatory respiratory diseases, such as asthma, COPD or COVID-19, can increase the degradation of the active metabolites of the VDES. The aim of this narrative revision is to report the current evidence on the role of calcifediol in main respiratory diseases. In conclusion, good 25OHD status may have beneficial effects on the clinical course of respiratory diseases, including COVID-19. This hypothesis should be confirmed in large, randomized trials. Otherwise, a rapid correction of 25(OH)D deficiency can be useful for patients with respiratory disease.

Vitamin d-fortified bread: Systematic review of fortification approaches and clinical studies

Vitamin d-fortified bread has been proposed as a strategy to increase the average daily intake and serum status of this nutrient. This review aimed to bring together the different types of scientific articles on vitamin d-fortified bread. The databases used for the research were PUBMED, WEB of SCIENCE and SCOPUS; all original indexed studies written in English, published between January 2000 and March 2021, were considered. Three important points were identified: i) theoretical models of fortification; ii) stability, bioaccessibility, and bioavailability studies of vitamin d-fortified breads; and iii) clinical effects of vitamin d-fortified breads. This review showed that vitamin d-fortified bread is a promising vehicle for fortification strategy effects, leading to increased serum concentrations of 25(OH)D and decreased parathyroid hormone. However, further studies are needed to elucidate the effects and effectiveness of this fortification strategy in the prevention/treatment of vitamin D deficiency.

Natural selection at work? Vitamin D deficiency rates and rising health problems in young Turkish Cypriot professionals

OBJECTIVES

Vitamin D is a fat-soluble, prohormone vitamin that is important especially for bone mineralization and skeletal health. In recent years, vitamin D deficiency appeared as a worldwide problem, affecting many people in different ways including the Northern Cypriot population. The deficiency might be caused by the lack of exposure to sunlight, diet low in vitamin D, sedentary lifestyle, and also due to some genetic variations in the vitamin D receptor (VDR) gene.

METHODS

In this study, four common VDR polymorphisms and associations with vitamin D deficiency in the Turkish Cypriot population between ages 18-40 and working in office conditions was studied by PCR- RFLP analysis.

RESULTS

rs2228570 C>T variant was shown to be significantly associated with low serum vitamin D levels in the studied population.

CONCLUSION

Together with the effect of rs2228570 C>T variant in the VDR gene, it is thought that the lifestyle changes in the Turkish Cypriot population might have caused the increased frequency of vitamin D deficiency in the young professionals.

Association of two types of dietary pattern scores with cardiovascular disease risk factors and serum 25 hydroxy vitamin D levels in Saudi Arabia

Background

Cardiovascular disease (CVD) is a main cause of mortality and disability worldwide. One of the key factors in the soaring prevalence of CVD globally has been nutrition transitions and changes in dietary patterns.

Objective

This study investigated the association between two diet scores, namely, a high-fat dietary (HFD) pattern score and a Mediterranean diet (MedDiet) score, and CVD risk factors (obesity, hypertension, total cholesterol, and blood glucose) and serum 25 hydroxy vitamin D (25[OH]D) levels.

Methods

Three hundred twenty-one participants were included in this study. Fasting blood tests were collected from all participants for biochemical measurements. Blood pressure and anthropometric measurements were also taken. A validated, semi-quantitative food frequency questionnaire was used to collect data on participants’ dietary intake. Dietary scores for the HFD pattern were calculated based on recommended food groups. MedDiet scores were calculated based on a previously validated method that contains 14 questions related to MedDiet. Both diet scores were classified into tertiles. Linear regression analyses were performed to assess the statistical significance of the tertile groups.

Result

A significant association was found between HFD score and obesity when comparing the lowest tertile (27.3±4.6 kg/m²) of HFD scores with the medium tertile (29.2±5.7 kg/m2; P = 0.02). A higher HFD score was significantly associated with lower 25(OH)D levels (P = 0.02). In addition, a significant association was observed between MedDiet scores and 25(OH)D levels, with an increase in MedDiet score resulting in an increase in 25(OH)D levels (P = 0.01). Furthermore, a significant negative association between MedDiet scores and low-density lipoprotein levels was reported only in participants with CVD (P = 0.03).

Conclusion

The results of this study revealed that HFD and MedDiet scores might have a role in the development of CVD and vitamin D deficiency among the Saudi Arabian population. Further studies are required using diet scores to assess the quality of dietary patterns and their association with an increased risk of diseases in Saudi Arabians.

Whether Adding Vitamin D to Tadalafil 5 mg Treatment Is Useful in Patients with Erectile Dysfunction and Vitamin D Deficiency?

INTRODUCTION

Numerous factors such as endothelial disease and hormonal disorder cause the development of erectile dysfunction (ED). However, the relationship between vitamin D deficiency (VDD) and ED is unclear. Moreover, the benefit of vitamin D replacement on ED patients with VDD is uncertain. As far as we know, there is no study yet in the literature regarding the addition of vitamin D to phosphodiesterase type 5 inhibitors in the treatment of ED patients with VDD. In this study, we investigated whether adding vitamin D to daily tadalafil treatment would be beneficial in ED patients with VDD.

METHODS

A total of 111 patients with VDD accompanying ED were retrospectively evaluated between January 2016 and December 2019. Patients were divided into 2 groups according to the treatment they received. Group 1 (n = 58) was treated with daily oral tadalafil 5 mg, while group 2 (n = 53) received oral tadalafil 5 mg and 4,000 IU vitamin D3. Total International Index of Erectile Function-15 (IIEF-15) scores and vitamin D levels of the groups were compared at the end of the study.

RESULTS

The mean vitamin D level was increased statistically significant in group 2, but no difference was seen in group 1 (p < 0.001 and p > 0.05, respectively). There was a significant increase in median erectile function, orgasmic function, sexual desire, sexual satisfaction, and overall satisfaction scores in both groups (p < 0.001). However, the increase in median erectile function and sexual desire scores was significantly higher in group 2 compared to group 1 at the end of the study (p = 0.01 and p < 0.001, respectively).

CONCLUSION

We found that adding vitamin D to 5 mg oral daily tadalafil treatment may have an additional positive effect on erectile function and sexual desire in ED patients with VDD.

25(OH)D3 stimulates the expression of vitamin D target genes in renal tubular cells when Cyp27b1 is abrogated

Recently, it was reported that 25(OH)D₃ (25D3) has physiological bioactivity in certain tissues derived from Cyp27b1 knockout mice. To investigate the function of 25D3 in the kidney as an informational crossroad of various calciotropic substances, we employed the CRISPR-Cas9 system to knock out Cyp27b1 in the mouse renal distal tubular mDCT cell line. Unlike the previously reported mice in which Cyp27b1 was targeted systemically, Cyp27b1 knockout mDCT cells did not produce any measurable 1α,25(OH)₂D₃ (1,25D3) after 25D3 administration. As was seen with treatment of Cyp27b1 knockout mDCT cells with ≥10^-8 M of 1,25D3, the administration of 10^-7 M of 25D3 translocated the vitamin D₃ receptor (VDR) into the nucleus and promoted the expression of the representative 1,25D3-responsive gene Cyp24a1. The exhaustive target gene profiles of 25D3 were similar to those of 1,25D3. Subsequently, we confirmed that 25D3 induced the expression of the calcium reabsorption-related gene calbindin-D9K, in a way similar to 1,25D3. We also found that 1,25D3 and 25D3 induced the expression of the megalin gene. A chromatin immunoprecipitation assay identified two vitamin D response elements in the upstream region of the megalin gene that seemed to contribute to its expression. Together, we surmise that the ability of 25D3 to stimulate VDR target genes may provide a novel perspective for its role in certain tissues.

Variations in 25-Hydroxyvitamin D in Countries from the Middle East and Europe: The Roles of UVB Exposure and Diet

Serum 25-hydroxyvitamin D (25(OH)D) has been largely associated with latitude and sunshine exposure across several regions. According to previous results, 25(OH)D concentrations are, on average, relatively low in countries with abundant sunshine, including those of the Middle East and North Africa region, as well as lower-latitude Europe. The standard explanation for this phenomenon is that people wear concealing clothing because of cultural and religious practices and that high temperatures in summer limit direct sun exposure. However, the role of diet in the development of profound hypovitaminosis D has not been adequately explored in those countries. To examine how diet affects vitamin D status in the Middle Eastern and European countries, a search was conducted for papers from that region reporting 25(OH)D concentrations. Papers were sought that reported summertime and wintertime 25(OH)D concentrations for healthy nonpregnant adults representative of the entire population. Data from 15 Middle Eastern and European countries were found through this search. Data for postmenopausal women from 19 European countries were also obtained. Dietary supply data for animal products containing vitamin D (animal fat, eggs, ocean fish, animal meat, and milk) were obtained from the Food and Agriculture Organization of the United Nations. Latitude and a solar UVB dose index also were obtained for each country. For the 15-country study, energy from dietary factors was highly correlated with latitude, making it difficult to separate the effects of UVB exposure and dietary factors. However, for the 19-country study, dietary factors were only weakly correlated with latitude. In that study, ocean fish was the most important single dietary factor affecting serum 25(OH)D concentration for postmenopausal women in various European countries, but animal fat and meat also contributed. Because this is an ecological study, further research is encouraged to evaluate and extend the findings.

Association between vitamin D and risk of cardiovascular disease in Chinese rural population

Previous studies have suggested that vitamin D is associated with cardiovascular disease (CVD), however, the relationship between vitamin D levels and CVD risk is still unclear. The purpose of this study was to assess the relationship of serum concentration of 25-hydroxyvitamin D (25(OH)D) with CVD in rural residents of Henan province of China. Basic information and medical history were gathered through face-to-face surveys from July 2013 to August 2015, and biochemical indicators were gathered in a laboratory setting. Logistic and restricted cubic splines regression analyses were used to estimate odd ratios (ORs) and 95% confidence intervals (95%CI) of CVD. A total of 1078 participants were included, the mean serum 25(OH)D concentration was determined to be 25 ± 18 ng/ml, with 54.45% of the participants presenting vitamin D deficiency [25(OH)D < 20 ng/mL]. Moreover, the prevalence of CVD was 59.28% in the vitamin D deficient group, which was higher than in the insufficient (48.55%) and sufficient groups (52.78%). After adjusting for potential confounders, compared with the deficient group, the ORs (95%CI) of CVDs were 0.68 (0.50, 0.91) in the insufficient group and 0.81 (0.56, 1.16) in the sufficient group. A nonlinear (U-shaped) association was observed between the risk of CVD and 25(OH)D concentration. Further research suggested that the risk of CVD was higher in males than in females. In conclusion, a U-shape association between serum levels of 25(OH)D and the risk of CVD was identified in our study, suggesting a nonlinear relationship between vitamin D with the prevalence of CVD.