Vitamin D and Sleep Regulation: Is there a Role for Vitamin D?

Association between Serum Vitamin D Status and Circadian Syndrome: A Cross-Sectional Study

BACKGROUND

Circadian Syndrome (CircS) encompasses cardiometabolic risk factors and comorbidities, indicating an elevated susceptibility to cardiovascular disease and type 2 diabetes.

METHODS

This cross-sectional study aimed to investigate the association between vitamin D levels and each of the following: CircS, metabolic syndrome (MetS), and the individual components of CircS. Data from 14,907 adults who participated in the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018 were utilized. CircS was defined based on MetS components, alongside depression, short sleep, and non-alcoholic fatty liver disease (NAFLD).

RESULTS

Our results indicated that low vitamin D levels exhibited meaningful associations with CircS, with vitamin D deficiency and inadequacy demonstrating 2.21-fold (95% CI 1.78-2.74, p < 0.001) and 1.33-fold (95% CI 1.14-1.54, p < 0.001) increases in CircS odds, respectively. The association between vitamin D deficiency and CircS was stronger than that with MetS. Additionally, a dose-response gradient in odds of CircS components, particularly with short sleep duration, was noted as serum vitamin D levels decreased.

CONCLUSIONS

our findings highlight a significant association between low serum vitamin D levels and CircS and its components, particularly with short sleep. This suggests a potentially pivotal role of vitamin D in the pathogenesis of Circadian syndrome.

Role of vitamin D in the association between pre-stroke sleep quality and poststroke depression and anxiety

PURPOSE

Poor sleep quality, mood disorders, and vitamin D deficiency are common in stroke. We investigated the association between serum vitamin D levels and pre-stroke sleep quality and the occurrence of poststroke depression (PSD) and poststroke anxiety (PSA) in acute ischemic stroke (AIS).

METHODS

This prospective cross-sectional study included hospitalized patients with AIS and age- and sex-matched controls. Vitamin D levels were measured within 24 h of admission. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) at admission. The severity of depression and anxiety symptoms was evaluated according to Beck Depression Inventory and Beck Anxiety Inventory scores, respectively, within 72 h after admission.

RESULTS

Comparing 214 AIS patients with 103 controls, patients had significantly higher scores of Beck Depression Inventory, Beck Anxiety Inventory, and PSQI and lower vitamin D levels (p < 0.001). Among AIS patients, Beck Depression Inventory (p = 0.004) and Beck Anxiety Inventory (p = 0.018) scores were significantly higher in bad sleepers (PSQI score ≥ 6) than in good sleepers (PSQI score ≤ 5). Correlation analysis revealed negative correlations between serum vitamin D levels and Beck Depression Inventory (r =  - 0.234; p < 0.001), Beck Anxiety Inventory (r =  - 0.135; p = 0.016), and PSQI (r =  - 0.218; p < 0.001) scores.

CONCLUSION

Decreased serum vitamin D levels at admission are associated with a high risk for PSD and PSA in patients with poor pre-stroke sleep quality during the early stages of AIS.

The role of interaction between vitamin D and VDR FokI gene polymorphism (rs2228570) in sleep quality of adults

To evaluate association of vitamin D with sleep quality in adults and the influence of VDR-gene polymorphism FokI (rs2228570;A > G). Cross-sectional population-based study in adults, conducted in Brazil. The outcome was sleep-quality, evaluated by the Pittsburgh Sleep Quality Index. Vitamin D was determined by indirect electrochemiluminescence and classified as deficiency (VDD), 25(OH)D < 20 ng/mL in a healthy population or 25(OH)D < 30 ng/mL for groups at risk for VDD. FokI polymorphism in the VDR-gene was genotyped by qPCR and classified as homozygous wild (FF or AA), heterozygous (Ff or AG), or homozygous mutant (ff or GG). Multivariate logistic analysis was used to estimate the association between vitamin D and FokI polymorphism with sleep-quality. In a total of 1674 individuals evaluated, 53.6% had poor-sleep-quality, 31.5% had VDD, and the genotype frequency of the FokI polymorphism was 9.9% FF, 44.6% Ff, and 45.5% ff. In multivariate analysis, individuals with VDD had 1.51 times the chance of poor-sleep-quality, and individuals with the ff genotype had 1.49 times the chance of poor-sleep-quality (OR:1.49;95%CI:1.05-2.12) when compared to individuals with the FF or Ff genotype. In the combined analysis, individuals with VDD and ff genotype had more chance of poor-sleep-quality than individuals with sufficient vitamin D and genotype Ff or FF (OR:2.19;95%CI:1.27-3.76). Our data suggest that VDD and VDR FokI gene polymorphism are associated with poor-sleep-quality, and combining the two factors increases the chance of poor-sleep-quality compared to separate groups.

Serum Vitamin D Levels Mediate the Association Between Physical Activity and Blood Pressure in Adolescents

Individuals with low levels of vitamin D are associated with cardiovascular risks, such as elevated blood pressure (BP), and are; therefore, more likely to develop hypertension. Patients with vitamin D deficiency may face an increased risk of cardiovascular events. In this study, a multicenter, cross-sectional, and school-based investigation was conducted as part of the ERICA project. The sample comprised 1152 adolescents aged 12-17 years from 4 Brazilian cities. Anthropometric variables, BP measurements, and hydroxyvitamin D concentrations were assessed. A 2-level linear regression was fitted to examine the relationship between each level of BP and independent variables. Our findings indicate that movement behaviors were not associated with BP levels, with the exception of sleep time, which demonstrated a positive association. However, after adjustment, this association was found to be nonsignificant. Our study's mediation analysis revealed that vitamin D mediates up to 12.9% of the association between physical activity and systolic BP. Vitamin D is inversely associated with BP in adolescents. In addition to mediating the physical activity and systolic BP association, engaging in physical activity, particularly outdoors, can provide a dual benefit for adolescents by increasing serum vitamin D levels and assisting in the control of BP levels.

Quercetin improved hepatic circadian rhythm dysfunction in middle-aged mice fed with vitamin D-deficient diet

We aimed to determine whether quercetin is capable of improving circadian rhythm and metabolism disorder under vitamin D-deficient condition. Middle-aged mice were randomly divided into four groups, namely, control (CON), vitamin D-deficient diet (VDD), quercetin (Q), and quercetin intervention in vitamin D-deficient diet (VDQ), with a total of 12 weeks' intervention. Mice were sacrificed at zeitgeber time1 (ZT1) and ZT13 time points. At ZT1, circadian locomotor output cycle kaput (CLOCK) protein expression from VDD, Q, and VDQ groups; CRY1 from Q group; and CRY2 from VDD group were significantly lower compared to CON group. The mRNA expression of Sirt1, Bmal1, Clock, Cry1, and Cry2 in VDQ groups, also Bmal1, Clock, and Cry1 from Q group, were significantly decreased compared to CON group. At ZT13, compared to CON group, fasting insulin and homeostasis model assessment-insulin resistance (HOMA-IR) were higher in VDD group; BMAL1 was significantly increased, while CLOCK and CRY1 protein were significantly decreased from VDD group; CLOCK protein from VDQ group was significantly higher compared to CON, VDD, and Q groups, and also, BMAL1 protein expression from VDQ group was elevated compared to CON group. The mRNA expression of Bmal1, Clock, Per2, Cry1, and Cry2 in VDQ groups were significantly increased compared to CON groups. The mRNA expression of Bmal1 from VDQ group was decreased compared to both VDD and Q group. In conclusion, vitamin D-deficient diet resulted in a disordered liver circadian rhythm, and quercetin improved the hepatic circadian desynchronization. Quercetin supplementation might be effective for balancing circadian rhythm under vitamin D-deficient condition.

The roles of serum vitamin D and tobacco smoke exposure in insomnia: a cross-sectional study of adults in the United States

Aim

Tobacco smoke exposure and vitamin D (VD) status were both associated with insomnia. However, the combined effect of smoking and VD on insomnia has not been discussed. This study aimed to explore the role of VD in the association between tobacco smoke exposure and insomnia.

Methods

Data on adults were extracted from the National Health and Nutrition Examination Surveys (NHANES) database in 2005-2008 for this cross-sectional study. Weighted univariate and multivariate logistic regression analyses were used to explore the associations between serum cotinine, serum VD, and insomnia. A surface diagram was drawn to reflect the effect of VD on the association between serum cotinine and insomnia. In addition, the potential regulating effect of VD in subgroups of smoking status was also performed. The evaluation index was odds ratios (ORs) with 95% confidence intervals (CIs).

Results

Among the eligible participants, 1,766 had insomnia. After adjusting for covariates, we found that elevated serum cotinine levels were associated with higher odds of insomnia [OR = 1.55, 95% CI: (1.22, 1.97)]. However, the relationship between serum VD level and insomnia was not significant (P = 0.553). Higher serum cotinine levels were also associated with higher odds of insomnia [OR = 1.52, 95% CI: (1.17, 1.98)] when serum VD level was <75 nmol/L; however, this relationship became non-significant when serum VD concentration was elevated (P = 0.088). Additionally, the potential regulating effect of VD was also found in adults who were not smoking.

Conclusion

VD may play a potential regulative role in the association between tobacco smoke exposure and insomnia. Further studies are needed to clarify the causal relationships between VD, tobacco smoke exposure, and insomnia.

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

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

Obstructive sleep apnea and vitamin D: an updated systematic review and meta-analysis

PURPOSE  : Obstructive sleep apnea (OSA) is a chronic, sleep-related breathing disorder which leads to increased cardiovascular risks. Vitamin D deficiency is associated with various cardiometabolic complications, including increased cardiovascular morbidity and mortality. We aimed to analyze the difference in serum 25-hydroxyvitamin D (25-OHD) level, prevalence of vitamin D insufficiency and deficiency, and the effect of CPAP treatment on serum 25-OHD levels among adult patients with OSA.

METHODS

We pooled data from 18 observational studies involving 5592 individuals. Baseline parameters that might have contributed to the significant differences observed were also analyzed.

RESULTS

Patients with OSA had significantly lower serum 25-OHD levels (pooled d +  - 0.74 [95% CI: - 1.19 to - 0.28], p < 0.01) and higher prevalence of vitamin D deficiency (pooled log (odds ratio) 0.98 [95% CI: 0.30 to 1.67], p < 0.01) compared to those without OSA. Subgroup analysis demonstrated that these differences were significant only in moderate OSA and severe OSA. Neither age nor BMI nor geographical latitude contributed significantly to the differences observed in serum 25-OHD levels. The use of CPAP did not lead to significant changes in serum 25-OHD levels.

CONCLUSION

Patients with OSA have lower serum 25-OHD levels with a higher prevalence of vitamin D deficiency, regardless of age or BMI, pointing to an independent association between vitamin D and OSA.

Seven-Month Vitamin D Deficiency Inhibits Gastric Epithelial Cell Proliferation, Stimulates Acid Secretion, and Differentially Alters Cell Lineages in the Gastric Glands

Vitamin D (VD) deficiency can result from insufficiency of either light exposure or VD intake. We investigated the biological effects of VD deficiency for 7 months on the mouse gastric glands. Varying degrees of VD deficiency were induced in C57BL/6 mice by keeping them on standard diet with constant-dark conditions (SDD) or VD deficient diet with constant-dark conditions (VDD). Samples of serum, glandular stomach, and gastric contents were collected for LCMS/MS, RT-PCR, immunohistochemistry, and acid content measurements. Both SDD and VDD mice had a significant decline in 25OHVD metabolite, gastric epithelial cell proliferation, and mucin 6 gene expression. These effects were enhanced with the severity of VD deficiency from SDD to VDD. Besides and compared to the control group, SDD mice only displayed a significant increase in the number of zymogenic cells (p ≤ 0.0001) and high expression of the adiponectin (p ≤ 0.05), gastrin (p ≤ 0.0001), mucin 5AC (*** p ≤ 0.001) and the Cyclin-dependent kinase inhibitor 1A (**** p ≤ 0.0001). These phenotypes were unique to SDD gastric samples and not seen in the VDD or control groups. This study suggests that the body reacts differently to diverse VD deficiency sources, light or diet.

The Mediation Role of Sleep Disturbances between Vitamin D and Depressive Symptoms: A Cross-Sectional Study

Depression and sleep disturbances are highly prevalent health problems that have been suggested to be associated with vitamin D deficiency. This study investigated whether sleep disturbances affect the association between vitamin D and depressive symptoms. A total of 425 patients with depression were included in this study. Spearman correlation coefficients were chosen to assess the relation between vitamin D concentrations and depressive symptomatology (according to the PHQ-9 and HAMD-17 scores). The GLM Mediation Model in the Medmod module for data analysis in Jamovi 2.2.5 was used to analyze the mediation models for sleep disturbances. Vitamin D concentrations were significantly correlated with PHQ-9 and HAMD-17 scale scores. In addition, item 3 was suggested to have a mediating effect between vitamin D and depressive symptoms in the mediating model of PHQ-9, and item 4 was suggested to have a mediating effect between vitamin D and depressive symptoms in the mediating model of HAMD-17. Sleep disturbances (especially difficulty falling asleep) are mediators between vitamin D and depressive symptoms, suggesting that increasing vitamin D levels at the right time to regulate sleep disturbances may improve depression symptoms, yet further research is necessary.

The saturation effect of 25(OH)D level on sleep duration for older people:The NHANES 2011-2018

This study aimed to investigate the potential relationship between vitamin D and sleep duration in older adults. The study utilized multivariate linear regression models to estimate the associations between serum 25(OH)D and sleep duration. In addition, a smooth curve fitting approach was used to identify any non-linear trends between the two variables. The study included 15,749 participants over the age of 60. The results showed a positive correlation between serum 25(OH)D levels and sleep duration in the fully-adjusted model. This correlation was observed in both males and females, as well as in non-Hispanic White and non-Hispanic Black participants. No significant interactions were found between serum 25(OH)D levels and the stratifying variables. The curve fitting analysis revealed a non-linear relationship between 25(OH)D and sleep duration, with a saturation point observed at a serum 25(OH)D level of 40.6 ng/mL. In conclusion, the findings suggest that there is a positive correlation between serum 25(OH)D levels and sleep duration, with a saturation effect observed. A positive correlation is evident when serum 25(OH)D falls below 40.6 ng/mL.

Osteoporosis and dermatoporosis: a review on the role of vitamin D

Osteoporosis (OP) and Dermatoporosis (DP) are expressions of the aging process at the skin and bone levels, respectively. Both conditions are associated with increased morbidity for elderly people, and this requires necessary interventions. They share many common risk factors; among these, vitamin D (VD) deficiency appears to have a role. VD is involved in either disease with many mechanisms, among which immunomodulation. VD deficiency has been linked to OP because it inhibits the body's capacity to absorb calcium and maintain optimal bone health. Available evidence suggests that proper vitaminosis D also appears to be vital in preventing skin age-related issues. DP is often seen in elderly individuals, particularly those with long-term sun exposure and a history of chronic sun damage. VD deficiency can be linked to DP, since its involvement in collagen production, epidermal barrier function, inflammation regulation, wound healing, and sun protection. Aim of this review is to summarize the most updated existing evidence on the role of VD in the development of fragility syndromes such as DP and OP and the possible benefits of VD supplementation as a simple and harmful weapon against aging.

Vitamin D and chronotype: is there any relationship in individuals with obesity?

PURPOSE

Chronotype is the attitude to perform most of the daily activities in the morning ("morning chronotype", MC) or in the evening ("evening chronotype", EC). The latter, as well as vitamin D deficiency, has been associated with an increased risk of obesity-related complications, likely through the promotion of insulin resistance. Therefore, we aimed to investigate whether there is any relationship between vitamin D (25-OH-D) and chronotype in individuals with obesity.

METHODS

In this cross-sectional study, we enrolled 59 individuals (43.1 ± 13 years; 17M/42F) with obesity. Anthropometric parameters, lifestyle habits, personal medical history, chronotype, insulin resistance, and 25-OH-D were assessed.

RESULTS

Individuals with EC presented significantly higher BMI than MC (p < 0.001), greater waist (p = 0.012), and hip circumferences (p = 0.001). Individuals with EC showed significantly lower insulin sensitivity (p = 0.017) and 25-OH-D than MC. In addition, the prevalence of vitamin D deficiency and impaired fasting glucose was significantly higher in EC than in MC. 25-OH-D directly correlated with chronotype score (r = 0.351; p = 0.019) whereas inversely with BMI (r = - 0.363; p = 0.016). The regression analysis showed that BMI was most tightly associated with 25-OH-D concentrations (β = - 0.323, p = 0.032), followed by chronotype score (β = 0.340, p = 0.042). Using chronotype score as the dependent variable, BMI significantly predicted a lower chronotype score (β = - 0.586, p < 0.001).

CONCLUSION

The present study showed that 25-OH-D, as well as chronotype, correlate independently with obesity.

Sleep Disturbances in Generalized Anxiety Disorder: The Role of Calcium Homeostasis Imbalance

Patients with a generalized anxiety disorder (GAD) often report preeminent sleep disturbances. Recently, calcium homeostasis gained interest because of its role in the regulation of sleep-wake rhythms and anxiety symptoms. This cross-sectional study aimed at investigating the association between calcium homeostasis imbalance, anxiety, and quality of sleep in patients with GAD. A total of 211 patients were assessed using the Hamilton Rating Scale for Anxiety (HAM-A), Pittsburgh Sleep Quality Index questionnaire (PSQI) and Insomnia Severity Index (ISI) scales. Calcium, vitamin D, and parathyroid hormone (PTH) levels were evaluated in blood samples. A correlation and linear regression analysis were run to evaluate the association of HAM-A, PSQI, and ISI scores with peripheral markers of calcium homeostasis imbalance. Significant correlations emerged between HAM-A, PSQI, ISI, PTH, and vitamin D. The regression models showed that patients with GAD displaying low levels of vitamin D and higher levels of PTH exhibit a poor subjective quality of sleep and higher levels of anxiety, underpinning higher psychopathological burden. A strong relationship between peripheral biomarkers of calcium homeostasis imbalance, insomnia, poor sleep quality, and anxiety symptomatology was underlined. Future studies could shed light on the causal and temporal relationship between calcium metabolism imbalance, anxiety, and sleep.

Association of Hypovitaminosis D with Sleep Parameters in Rotating Shift Worker Drivers

Objective  To evaluate the association between sleep parameters and hypovitaminosis D in rotating shift drivers. Material and Methods  We conducted a cross-sectional study on 82 male rotating shift workers (24-57 years old) with at least one cardiovascular risk factor (such as hyperglycemia, dyslipidemia, abdominal obesity, physical inactivity, hypertension, and smoking). Polysomnography was used to evaluate sleep parameters. Logistic regression was used to model the association between hypovitaminosis D and sleep parameters after adjustment for relevant covariates. Results  Hypovitaminosis D (< 20 ng/mL) was seen in 30.5% of the workers. Shift workers with hypovitaminosis D had lower sleep efficiency (odds ratio [OR]: 3.68; 95% confidence interval [CI]: 1.95-5.53), lower arterial oxygen saturation (OR: 5.35; 95% CI: 3.37-6.12), and increased microarousal index (OR: 3.85; 95% CI: 1.26-5.63) after adjusting. Conclusion  We suggest that hypovitaminosis D is associated with greater sleep disturbances in rotating shift workers.

Examination of correlations between vitamin D and melatonin levels with sleep among women aged 18-49 years

OBJECTIVES

Although clinical research is still going on to determine any relationship between vitamin D and sleep regulation, only few studies have identified the role of vitamin D metabolism in sleep disorders. The current study aims to examine the incidence of vitamin D deficiency/insufficiency in the sample group and its effects on sleep quality and melatonin level.

METHODS

A cross-sectional study was designed. A total of 79 women aged 18-49 years who applied to the research and training hospital between 1 October and 30 November 2021 participated in the study. Data were collected using a socio-demographic questionnaire prepared by the authors and the Pittsburgh Sleep Quality Index (PSQI). Blood samples were taken from the participants, also, 25-OH-vitamin D3 and melatonin levels in serum samples were measured by ELISA.

RESULTS

The participants (n = 79) were aged 29.61 ± 11.14 years. The mean total PSQI scores of the participants were calculated as 5.77 ± 2.70. We determined that 64.6% of the participants had vitamin D deficiency, 21.5% had vitamin D insufficiency, and 13.9% of the participants were vitamin D sufficient. The mean melatonin level was found to be 24.77 ± 27.77 ng/L. We determined that an increase in the melatonin levels decreases the risk of vitamin D deficiency. Besides, our findings showed a good positive correlation between serum melatonin and 25 OH vitamin D3 levels (r = 0.544, p < 0.001).

CONCLUSION

Our results indicate that the correction of vitamin D insufficiency can positively affect melatonin levels, therefore, it may positively contribute to the treatment of sleep disorders related to melatonin deficiency.

Influence of sunlight on the association between 25-hydroxyvitamin D levels and sleep quality in Brazilian adults: A population-based study

OBJECTIVES

This study aimed to evaluate the association of vitamin D with sleep quality during the COVID-19 pandemic and the influence of daily sunlight on this association.

METHODS

This cross-sectional, population-based study among adults stratified by multistage probability cluster sampling was conducted from October to December 2020 in the Iron Quadrangle region of Brazil. The outcome was sleep quality, evaluated by the Pittsburgh Sleep Quality Index. Vitamin D (25-hydroxyvitamin D) concentrations were determined by indirect electrochemiluminescence and a deficiency was classified as 25(OH)D < 20 ng/mL. To assess sunlight, the average daily sunlight exposure was calculated and was classified as insufficient when less than 30 min/d. Multivariate logistic analysis was used to estimate the association between vitamin D and sleep quality. A directed acyclic graph was used to select minimal and sufficient sets of adjustment variables for confounding from the backdoor criterion.

RESULTS

In a total of 1709 individuals evaluated, the prevalence of vitamin D deficiency was 19.8% (95% CI, 15.5-24.9%), and the prevalence of poor sleep quality was 52.5% (95% CI, 48.6-56.4%). In multivariate analysis, vitamin D was not associated with poor sleep quality in individuals with sufficient sunlight. Moreover, in individuals with insufficient sunlight, vitamin D deficiency was associated with poor sleep quality (odds ratio [OR], 2.02; 95% CI, 1.10-3.71). Furthermore, each 1-ng/mL increase in vitamin D levels reduced the chance of poor sleep quality by 4.2% (OR, 0.96; 95% CI, 0.92-0.99).

CONCLUSIONS

Vitamin D deficiency was associated with poor sleep quality in individuals with insufficient exposure to sunlight.

The Relationship between Sleep Duration and Metabolic Syndrome Severity Scores in Emerging Adults

BACKGROUND

Research suggests sleep duration can influence metabolic systems including glucose homeostasis, blood pressure, hormone regulation, nervous system activity, and total energy expenditure (TEE), all of which are related to cardiometabolic disease risk, even in young adults. The purpose of this study was to examine the relationship between sleep duration and metabolic syndrome severity scores (MSSS) in a sample of emerging adults (18-24 y/o).

METHODS

Data were collected between 2012 and 2021 from the College Health and Nutrition Assessment Survey, an ongoing, cross-sectional study conducted at a midsized northeastern university. Anthropometric, biochemical, and clinical measures were obtained following an overnight fast and used to assess the prevalence of metabolic syndrome (MetS). MetS severity scores (MSSS) were calculated using race- and sex-specific formulas. Sleep duration was calculated from the difference in self-reported bedtime and wake time acquired through an online survey. ANCOVA was used to examine the relationship between sleep duration and MetS severity score while adjusting for covariates (age, sex, BMI, physical activity level, smoking status, alcohol consumption, and academic major).

RESULTS

In the final sample (n = 3816), MetS (≥3 criteria) was present in 3.3% of students, while 15.4% of students presented with ≥2 MetS criteria. Mean MSSS was -0.65 ± 0.56, and the reported sleep duration was 8.2 ± 1.3 h/day. MSSS was higher among low sleepers (<7 h/day) and long sleepers (>9 h/day) compared to the reference sleepers (7-8 h/day) (-0.61 ± 0.02 and -0.63 ± 0.01 vs. -0.7 ± 0.02, respectively, p < 0.01).

CONCLUSIONS

Our findings suggest short (<7 h/day) and long (>9 h/day) sleep durations raise the risk of MetS in a sample of emerging adults. Further research is needed to elucidate the impact of improving sleep habits on future disease risk.

Association Between Vitamin D Levels and the Atherogenic Index of Plasma Among Chinese with Type 2 Diabetes Mellitus

PURPOSE

The relationship between atherogenic index of plasma (AIP) values and 25-hydroxyvitamin D (25[OH] D) was examined in type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

Six hundred and ninety-eight T2DM patients were included. Patients were allocated to two groups, namely, the vitamin D-deficient and non-deficient groups (threshold of 20 ng/mL). The AIP was determined as log (TG [mmol/L] / HDL-C [mmol/L]). The patients were then allocated to two further groups according to the median AIP value.

RESULTS

AIP level in the vitamin D-deficient group was significantly higher than that in non-deficient group (P<0.05). Patients with high AIP values had markedly reduced levels of vitamin D levels compared with those in the low-AIP group [15.89 (11.97, 20.29) VS 18.22 (13.89, 23.08), P<0.001]. Patients in the high AIP group had a higher rate of vitamin D deficiency (73.3% VS 60.6%). It was found that AIP values were adversely and independently correlated with vitamin D levels. The AIP value was shown to independently predict vitamin D deficiency risk in T2DM patients.

CONCLUSION

Patients with T2DM were shown to have an increased risk of vitamin D insufficiency when their AIP levels were low. This suggests that AIP is associated with vitamin D insufficiency in Chinese patients with type 2 diabetes.

Vitamin D deficiency promoting non-24 h sleep-wake disorder: a case report

We report a case of an emmetropic woman with excessive daytime sleepiness in alternation with insomnia consistent with the diagnosis criteria of a non-24 h sleep-wake disorder. After being refractory to the usual non-pharmacologic and pharmacologic treatment, we detected a deficiency of vitamin B12, vitamin D3, and folic acid. Substitution of these treatments led to a return of a 24 h sleep-wake rhythm though this remained independent from the external light-dark cycle. The question arises whether the vitamin D deficiency could be regarded as an epiphenomenon or whether there is an up-to-date unknown connection to the inner zeitgeber.

Behavioral and Dietary Habits That Could Influence Both COVID-19 and Non-Communicable Civilization Disease Prevention-What Have We Learned Up to Now?

The massive expansion of the new coronavirus SARS-CoV-2 has urged countries to introduce lockdowns and set restrictive actions worldwide. The focus of the studies was to determine how COVID-19 induces damage to the lungs in order to find an alternative or adjuvant therapy that could lead to preventing COVID-19 or at least ameliorating it. This paper aims to survey the literature and provide new insights into behavioral and dietary habits that could influence the prevention of COVID-19. Maintaining an adequate mental health status, sleep, and taking moderate exercise are often disrupted in the conditions of lockdown and are followed by weakened immunity. Mediterranean and vegetarian diets are superior to other eating patterns in terms of immunity boosting and fighting COVID-19. Our study showed how adequate hydration, green tea intake, and supplementation with vitamins D, C, and E can increase our chances of avoiding the infection and even help us sleep better. Another focus of the research was on determining what level of hygiene really increases one's chances of not contracting SARS-CoV-2, but this seems a little counter-intuitive at first. Since an immunocompromised state is a familiar predisposing factor for all contagious diseases, maintaining healthy behavioral and dietary habits could be a crucial step in boosting immunity and preventing COVID-19.

Association between adherence to the dietary approaches to stop hypertension (DASH) diet and maternal and infant sleep disorders

Background

Maternal diet is known to be important to both mother and infant health. The purpose of this study was to evaluate the association between adherence to the Dietary Approaches to Stop Hypertension (DASH) dietary pattern (DP) and sleep problems in mothers and their infants.

Methods

The study included 350 breastfeeding mothers with an average age of 29.5 ± 5.9 years. Psychological functions were performed using standard questionnaires, including a Quality-of-Life Questionnaire (QLQ), Edinburgh Postnatal Depression Scale (EPDS), Spielberger Anxiety Questionnaire (SAQ), Pittsburg Sleep Quality Index (PSQI), and Infant Sleep Questionnaire (ISQ). Also, a standardized food frequency questionnaire (FFQ) was used to identify adherence to the DASH DP.

Results

Subjects in the highest tertile of DASH DP had significantly lower scores of mother’s sleep latency (0.70 ± 1.18 vs. 1.24 ± 1.3; P value = 0.031), sleep disorders (4.3 ± 1.6 vs. 5.3 ± 2.4; P value= 0.032) and higher mother sleep efficiency compared to those in the lowest tertile (97.5 ± 89 vs. 54.8 ± 90; P value= 0.011). Also, infants of mothers with higher adherence to a DASH DP had lower sleep disorders compared with subjects with low adherence (4.9 ± 3.8 vs. 5.7 ± 3.2; P value= 0.017). After controlling for the mother’s education, economic status, age, body mass index (BMI), and energy intake, adherence to the DASH pattern was associated with shorter sleep latency (β = 0.60; 95%CI: 0.49–0.82), fewer sleep disorders score in mothers (β = 0.92; 95%CI: 0.85–0.99) and their infants (β = 0.90; 95%CI: 0.84–0.96) as well as high mother’s sleep efficiency (β = 1.2; 95%CI: 1.1–1.31).

Conclusions

According to our findings, adherence to DASH DP is associated with a lower score for sleep disorders in mothers and their infants.

Associations of serum 25-hydroxyvitamin D and subjective sleep measures in an Arctic population: Insights from the population-based Tromsø Study

Objective

To investigate the relation between serum 25-hydroxyvitamin D (s-25(OH)D) and subjective sleep measures in an Arctic population (69°N).

Methods

Cross-sectional data was collected from 21,083 individuals (aged ≥40 years) participating in the population based Tromsø Study: Tromsø7 (2015–2016). The present study included 20,438 participants, after having excluded respondents missing data on s-25(OH)D (n = 161) and/or subjective sleep measures (including sleep duration, insomnia, and daytime sleepiness)(n = 490). Based on s-25(OH)D (assessed using LC-MS/MS), participants were grouped as deficient (<30 nmol/L), insufficient (30–49.9 nmol/L), sufficient (50–75 nmol/L), or high (>75 nmol/L). Sleep duration was grouped as inadequate (ISD) if < 7 or ≥9 h. Linear and logistic regression were used to calculate unstandardized β-values and odds ratios [95% confidence intervals]. The analyses were adjusted for season, age, BMI, lifestyle factors and relevant comorbidities.

Results

In both men and women, s-25(OH)D was positively associated with sleep duration, and compared to the sufficient s-25(OH)D group, the insufficient s-25(OH)D group reported significantly shorter sleep duration in both sexes. There was an increased odds of ISD in both men and women but adjusted for confounding factors this was only significant in women (1.16 [1.03, 1.32], p = .017). In men, there were no significant associations between s-25(OH)D and the remaining sleep measures. Women in the high s-25(OH)D group had lower ESS-scores (−0.28 [-0.47, −0.08], p = .006), but higher odds of insomnia (1.16 [1.01, 1.33], p = .036) compared to women in the sufficient group.

Conclusions

In this Arctic population, a tenuous association was found between s-25(OH)D and subjective sleep measures, predominantly in women.

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25(OH)D was associated with self-reported sleep measures in this Arctic population.

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25(OH)D was positively associated with self-reported sleep duration in both sexes.

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Women with sufficient 25(OH)D had lower odds of insomnia.

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RCTs are needed to determine the role of vitamin D in sleep health.

Reduced serum vitamin D levels are associated with poor sleep quality in early stroke patients

Background

Poor sleep quality and vitamin D deficiency are common in stroke patients. Our aim was to evaluate the possible association between vitamin D and sleep quality in acute ischemic stroke (AIS) patients.

Methods

A total of 301 AIS patients were screened and completed 1-month follow-up. Serum 25-hydroxyvitamin D [25(OH)D] was used to assess the vitamin D status by a competitive protein-binding assay at baseline. All patients were divided into equal quartile according to the distribution of 25(OH)D. One month after stroke, sleep quality was evaluated by using Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) questionnaire; depression status was confirmed by 17-item Hamilton Depression Scale (HAMD).

Results

There were 89 (29.6%) AIS patients with poor sleep quality 1-month post-event. Within 24 h after admission, serum 25(OH)D levels were significantly lower in patients with poor sleep quality after stroke (P &lt; 0.001). In the results of multivariate-adjusted logistic regression analysis, the odds ratio (OR) of poor sleep quality was 6.199 (95% CI, 2.066–18.600) for the lowest quartile of 25(OH)D compared with the highest quartile. In patients without depression, reduced 25(OH)D were still significantly associated with poor sleep quality (OR = 8.174, 95% CI = 2.432–27.473). Furthermore, 25(OH)D and HAMD score were combined to enhance the diagnostic accuracy of poor sleep quality, with the area under the receiver operating characteristic curve of 0.775.

Conclusion

Reduced serum levels of vitamin D at admission were independently and significantly associated with poor sleep quality at 1 month after stroke. Our findings suggested the combination of vitamin D and depression status could provide important predictive information for post-stroke sleep quality.

Vitamin D Supplementation and Sleep: A Systematic Review and Meta-Analysis of Intervention Studies

Background: Vitamin D deficiency is associated with sleep disorders and poor sleep quality. Whether vitamin D supplementation (VDS) helps resolve these problems remains unclear. Objective: To systematically review the effect of VDS on sleep quantity, quality, and disorders, and perform a meta-analysis of available data. Methods: The reporting of this review followed the PRISMA statement. VDS human interventions studies that reported on sleep quality, quantity, or disorders were included. Medline, CINAHL, EMBASE, PsycInfo, the Cochrane Library, Clinicaltrials.gov, and the ICTRP were searched, in addition to the references of the included articles and previous relevant reviews, without language or time restrictions. Included studies were critically appraised, findings were narratively synthesized, and a meta-analysis was conducted. Furthermore, the overall certainty of the evidence was assessed. Results: A total of 19 studies were included (13 randomized controlled trials (RCTs), 1 opportunistic addition to an RCT, 4 pre−post studies, and 1 pre−post study analyzed as a case series); 3 RCTs were meta-analyses. The risk of bias was generally low. Pre−post studies showed a significant improvement in sleep quality with VDS. Similarly, the results of the meta-analysis revealed a statistically significant decrease in the Pittsburgh Sleep Quality Index with VDS compared with placebo (mean difference, −2.33 (95% CI, −3.09, −1.57); p < 0.001; I2 = 0%), with a moderate certainty of evidence. The results regarding the effect of VDS on sleep-related impairment, difficulty, and disorders, as well as sleepiness and restless legs syndrome, were not unanimous. Conclusions: VDS is promising in improving sleep quality; however, its effect on sleep quantity and disorders needs to be further investigated.

A Randomized Double-Blind Placebo-Controlled Evaluation of the Safety and Efficacy of Wild Sage Metabolites in Preventing Snoring, Improving Sleep, and Activating Alpha Wave Brain Frequencies in Healthy Adults

Upper airway problems and stress can cause sleep disorders. The present study was designed to evaluate the efficacy and safety of wild sage metabolites (WSM) for snoring treatment and alpha wave activation in healthy men and women. A total of 42 subjects compliant with inclusion criteria were randomly assigned to one of the two groups, viz. Group 1-WSM and Group 2-Placebo, using a simple randomization process. Consumption of WSM by healthy men and women resulted in the decrease of Pittsburgh Sleep Quality Index (PSQI) global score by 29%, improved assessment by their sleep mates, and increased alpha brain wave by 55%. In conclusion, medication with WSM resulted in significant reduced snoring, stress, and improved sleep quality after 30 days, with a good tolerance among subjects. No side effects or adverse events were reported during the study. Hence, WSM at 450 mg/day could be recommended as an effective agent for snoring treatment, improving the quality of sleep, and stress reduction.

Determinants of poor sleep quality in adults during the coronavirus disease pandemic: COVID-Inconfidentes, a population-based study

BACKGROUND

The coronavirus disease (COVID-19) pandemic has adversely affected the health of the global population, with sleep quality being one of the affected parameters.

OBJECTIVES

To evaluate sleep quality and its associated factors in adults during the COVID-19 pandemic in Brazil.

DESIGN AND SETTING

A population-based cross-sectional serological survey of 1,762 adults in the Iron Quadrangle region of Brazil.

METHODS

The Pittsburgh Sleep Quality Index was used to assess sleep quality. Sociodemographic variables, health conditions, health-related behaviors, anxiety, vitamin D levels, weight gain/loss, and pandemic characteristics were assessed using a structured questionnaire. Univariate and multivariate analyses using Poisson regression with robust variance were performed to identify factors associated with sleep quality.

RESULTS

More than half of the participants reported poor sleep quality (52.5%). Multivariate analysis revealed that the factors associated with poor sleep quality included living alone (prevalence ratio [PR] = 1.34; 95% confidence interval [CI]: 1.04-1.73), anxiety disorder (PR = 1.32; 95% CI: 1.08-1.62), 5.0% weight loss (PR = 1.21; 95% CI: 1.02-1.44), 5.0% weight gain (PR = 1.27; 95% CI: 1.03-1.55), vitamin D deficiency (PR = 1.16; 95% CI: 1.01-1.35), and COVID-19 symptoms (PR = 1.29; 95% CI: 1.10-1.52).

CONCLUSIONS

Our study revealed that more than half of the participants experienced poor sleep quality during the COVID-19 pandemic. Factors associated with poor sleep quality included vitamin D deficiency and weight changes related to the pandemic.

Analysis of Serum Vitamin D Level and Related Factors in Patients With Restless Legs Syndrome

Objective: This study aimed to detect serum vitamin D (VitD) levels in patients with primary restless legs syndrome (RLS). The further objective was to analyze the relationship of VitD levels with the severity of RLS symptoms, sleep, anxiety, and depression.

Methods: The serum 25-hydroxyvitamin D [25(OH)D] levels of 57 patients with primary RLS and the healthy physical examinees in our hospital during the same period were detected. The International Restless Legs Syndrome Study Group (IRLSSG) rating scale for measuring RLS severity and Pittsburgh Sleep Quality Index (PSQI) Scale, 24-item Hamilton Depression Rating Scale (HAMD₂₄), and 14-item Hamilton Anxiety Scale (HAMA₁₄) were used to assess the severity of symptoms, sleep, and emotional state of patients with RLS. Based on VitD level and IRLSSG score, they were grouped for analysis.

Results: The serum 25(OH)D level was significantly lower in patients with RLS than in healthy controls, and the incidence of insufficient serum VitD levels was significantly higher in patients with RLS than in healthy people (both P < 0.05). The serum VitD level was significantly lower in (extremely) severe patients with RLS than in mild to moderate patients with RLS (P < 0.05). The IRLSSG scale score and HAMD₂₄ score were significantly higher in patients with RLS with insufficient serum VitD levels than those with normal serum VitD levels (both P < 0.05). Correlation analysis of IRLSSG scale score with serum VitD level and each scale score in patients with RLS showed that IRLSSG scale score was negatively correlated with VitD level, but positively correlated with PSQI, HAMA₁₄, and HAMD₂₄ scores. The results of correlation analysis between serum VitD levels and each scale score in patients with RLS indicated that serum VitD levels were negatively correlated with IRLSSG scale scores, PSQI scores, and HAMD₂₄ scores.

Conclusion: The serum VitD level is generally lower in patients with RLS than in healthy people, and lower serum VitD level is associated with more severe symptoms of RLS, worse quality of sleep, and worse depression.

No improvement of sleep from vitamin D supplementation: insights from a randomized controlled trial

Background

Vitamin D has been linked to sleep health in observational studies. Data from randomized controlled trials (RCTs) with vitamin D is scarce.

Methods

This study presents the results of a secondary analysis of 189 vitamin D insufficient participants (47.1% women) in a previously performed RCT, of which 92 were randomized to vitamin D (100,000 IU (2500 μg) as a bolus dose followed by 20,000 IU (500 μg) per week), and 97 to placebo. At baseline and after 4 months at the end of the study serum 25-hydroxyvitamin D (s-25(OH)D) was measured, and the study questionnaire assessing sleep duration, daytime sleepiness, and symptoms of insomnia, was completed.

Results

At baseline, mean s-25(OH)D was 35.0 ± 11.8 and 35.5 ± 13.3 nmol/L in the vitamin D and placebo groups, respectively. After four months, we found no statistically significant differences between the intervention groups in any of the assessed sleep outcomes, neither when stratified by sex, nor when performed in subgroups based on baseline or end of study s-25(OH)D level or presence of sleep complaints at baseline.

Conclusions

We were not able to demonstrate a significant effect of vitamin D supplementation on sleep in this vitamin D insufficient population.

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RCT investigating vitamin D for 4 months in participants with low vitamin D status.

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Vitamin D did not improve sleep duration, excessive daytime sleepiness or insomnia.

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The role of vitamin D in sleep health remains controversial.

Is there a relationship between the ketogenic diet and sleep disorders?

Sleep disorders are very often underestimated and, consequently, not treated with due priority. Common sleep disorders include insomnia disorders, sleep-related breathing disorders, central disorders of hypersomnolence, circadian rhythm sleep-wake disorders, sleep-related movement disorders, parasomnias, and other sleep disorders. The ketogenic diet (KD) is rich in fat, low in carbohydrates (CHO), and adequate in protein. The KD has shown several applications in treating medical conditions, such as epilepsy, neurodegenerative disorders, obesity with its comorbidities, and sleep disorders, with encouraging results. Therefore, the purpose of this review is to address the primary sleep disorders and their respective standard therapeutic approaches, analyse the effect of ketone bodies (KBs) on sleep homeostasis, and the effects of KD on sleep disorders and in particular on obstructive sleep apnoea (OSA) syndrome. The goal is to summarise the evidence existing up to now on the subject, to provide a starting point for further investigations.

The Association of Sleep Quality and Vitamin D Levels in Hemodialysis Patients

Background

To date, hemodialysis (HD) is the most common therapy for chronic kidney disease (CKD) patients. However, it causes different complications such as sleep disorders. Sleep regulation is connected to vitamin D; hence, its deficiency might influence the quality and duration of sleep. This study is aimed at evaluating the correlation of sleep quality and vitamin D levels in 80 HD patients.

Methods

This cross-sectional study was performed on 80 hemodialysis patients admitted to 29 Bahman hospitals in Tabriz, Iran. Before beginning of dialysis, serum 25 (OH) D levels were assessed among patients and the sleep patterns and sleep quality of patients were accurately calculated by the Pittsburgh sleep quality index (PSQI) standard questionnaire.

Results

Our results showed that 22 HD patients (27.5%) had severe sleep disorders. In addition, it was found that serum levels of vitamin D had significant correlation with sleep quality (r = −0.341, p = 0.002) in general, even after adjusting confounding factors such as calcium (Ca), phosphate (P), and parathyroid hormone (PTH) level. In poor sleepers (PSQI ≤ 5), a negative correlation was observed between the levels of vitamin D and PSQI score (r = −0.397, p = 0.004). PSQI scores in the normal range of PTH (r = −0.377, p = 0.006) and in >600 pg/ml of PTH (r = −0.675, p = 0.011) had a correlation with vitamin D levels. The level of vitamin D was the single independent predictor of sleep efficiency (β coefficient = −0.386, p = 0.001).

Conclusion

The present project reported that the positive effect of vitamin D is associated with sleep disorder in HD patients. In future studies, normal levels of Ca and P should be considered along with normal vitamin D levels among the included patients.

Nightmares and bad dreams among individuals with musculoskeletal pain: a link to vitamin D and calcium

Nightmares are frightening or disturbing dreams that awaken sleepers while bad dreams are disturbing dreams that do not awaken sleepers. Both types are known to be associated with psychological symptoms including anxiety and depression. Chronic pain is often comorbid with psychological symptoms and vitamin D deficiency increases risk of chronic musculoskeletal pain (MSP), which in turn is associated with increased risk of anxiety and depression. We aimed to investigate associations between types of dreams, psychological symptoms, vitamin D, and calcium intake in individuals with MSP. The study included 191 outpatients with MSP and 191 age/gender matched healthy controls. Psychological symptoms were assessed using Hospital Anxiety and Depression Scale. Serum vitamin D was measured and daily calcium intake was estimated. Participants were asked about types of their dreams (normal, bad, or nightmares) during the past month. Binary logistic regression was used to find predictors of MSP and bad dreams and nightmares. Bad dreams and nightmares, vitamin D deficiency, low calcium intake, anxiety, and depression were more prevalent in cases versus controls (Ps<0.001). Chi-square analyses showed that types of dreams were associated with anxiety, depression, and MSP (Ps<0.001). Participants with normal dreams had higher vitamin D (P<0.01) and calcium intake (P<0.001) and lower anxiety and depression scores (Ps<0.001) compared to participants with bad dreams and nightmares. Anxiety, depression and MSP were predictors for bad dreams and nightmares. Further studies are required to assess if vitamin D supplementation and increasing calcium intake may improve MSP, psychological symptoms and thus prevent nightmares and bad dreams.

The Impact of COVID-19 Pandemic during 2020-2021 on the Vitamin D Serum Levels in the Paediatric Population in Warsaw, Poland

BACKGROUND

The main source of vitamin D is skin synthesis, which depends on sunlight exposure. During the pandemic, COVID-19 children were obliged to home confinement, which potentially limiting sunlight exposure. The aim of this study was to evaluate whether home confinement led to decreased vitamin D serum levels in children in Warsaw, Poland.

METHODS

The study included 1472 children who were divided into two groups, based on the date of 25(OH)D level blood sampling: before and during the pandemic. Children under 1 year of age (infants) were analysed separately.

RESULTS

A statistically significant decrease in the average level of vitamin D was observed between groups of children over 1 year of age (35 ng/mL ± 18 vs. 31 ng/mL ± 14). In infants from both groups, the mean vitamin D levels were within the normal range (Group 1 inf 54 ng/mL ± 21 vs. Group 2 inf 47 ng/mL ± 15). The characteristic seasonal variability was observed before the pandemic, with maximal vitamin D levels in summer (40 ng/mL ± 17) and minimal levels in winter (30 ng/mL ± 14). During the pandemic, no seasonal variability was observed (summer 30 ng/mL ± 11 vs. winter 30 ng/mL ± 19).

CONCLUSIONS

The COVID-19 pandemic restrictions led to a significant decrease in vitamin D serum levels in children.

Vitamin D and sleep duration: Is there a bidirectional relationship?

Vitamin D contributes to numerous physiological processes within the body but primarily calcium and bone homeostasis. Emerging evidence highlights a novel role for vitamin D in maintaining and regulating optimal sleep. Sleep is a known regulator of bone health, highlighting the interconnectedness between vitamin D concentrations, sleep duration and bone metabolism. It is possible that the relationship between sleep length and vitamin D is bidirectional, with vitamin D playing a role in sleep health and conversely, sleep affecting vitamin D levels. Nevertheless, limited information on the direction of the interaction is available, and much remains to be learned concerning the complex relationship between insufficient sleep duration and vitamin D deficiency. Given the potential to implement interventions to improve sleep and vitamin D supplementation, understanding this relationship further could represent a novel way to support and improve health.

Improving sleep disturbances in obesity by nutritional strategies: review of current evidence and practical guide

Over the past decades, there has been an increase in overweight and obesity worldwide rates in both in adult and children. In parallel, it has been reported a worsening of sleep duration and quality. Some studies have shown an association between obesity and sleep disturbances (SD) vice versa, subjects with obesity have a greater risk of SD. As well as SD influences diet, also food choices have been shown to influence various sleep-related variables, such as duration and quality. For this reason, nutrition could represent an important tool not only to lose weight but also to improve sleep in patients with obesity and sleep disturbances. Thus, the aim of this review is to provide an overview of the studies that assessed the association between obesity and SD and vice versa, highlighting possible nutritional advices as a tool to improve sleep in patients with obesity and sleep disturbances.

Vitamin D in obesity and obesity-related diseases: an overview

Hypovitaminosis D and obesity represent two pandemic conditions sometimes associated with each other. Although it is known that there is a close relationship between these two health problems, the underlying pathophysiological mechanism has not yet been fully clarified. In fact, on the one hand, obesity per se seems to involve low circulating levels of vitamin D due to low sun exposure, physical activity, and intake of foods rich in vitamin D, volumetric dilution and sequestration in the adipose tissue. Conversely, since preadipocytes and adipocytes express the receptors and are involved in the metabolism of vitamin D it would seem that low levels of this vitamin may be involved in adipogenesis and therefore in the development of obesity. This connection is extremely important when considering obesity-related diseases. In fact, low vitamin D levels and severe obesity are significantly associated with some cardio-metabolic risk factors, including high Body Mass Index, waist circumference, blood pressure, impaired lipid and glycemic profile and insulin resistance, as they would seem associated with worse cardiovascular outcomes and higher cancer incidence and mortality. Therefore, the purpose of this review was to examine the recent evidence linking low vitamin D status, obesity and obesity-related diseases, highlighting the scientific achievements and the gaps to be filled with further investigations.

[Power station sun and hormone factory skin : A current assessment of the importance of vitamin D metabolism during human evolution and strategies for UV prevention]

The sun is of great importance for human health. One important reason for this is the production of vitamin D, endorphins and many other hormones by the skin due to stimulation by sunlight. Insufficient access to sunlight increases the risk for vitamin D deficiency, a pandemic which would affect more than one billion people worldwide and under which ca. 60% of the population in Germany would suffer. The skin has a unique position in vitamin D metabolism as elementary steps for vitamin D production take place here and it is furthermore a target organ for actions of vitamin D. Due to the many positive effects of the sun, a healthy balance must be found between UV protection to shield against skin cancer but also ensuring sufficient vitamin D production. For regulation of this fragile balance between photoprotection and vitamin D production, which has accompanied mankind throughout evolution, sunscreens are an integral part of the modern lifestyle, although critical reports on possible risks for their use have recently become more frequent. This article discusses the current state of knowledge on the importance of vitamin D metabolism in human skin and the use of sun creams.

Antiviral Functional Foods and Exercise Lifestyle Prevention of Coronavirus

Novel coronavirus (COVID-19) is causing global mortality and lockdown burdens. A compromised immune system is a known risk factor for all viral influenza infections. Functional foods optimize the immune system capacity to prevent and control pathogenic viral infections, while physical activity augments such protective benefits. Exercise enhances innate and adaptive immune systems through acute, transient, and long-term adaptations to physical activity in a dose-response relationship. Functional foods prevention of non-communicable disease can be translated into protecting against respiratory viral infections and COVID-19. Functional foods and nutraceuticals within popular diets contain immune-boosting nutraceuticals, polyphenols, terpenoids, flavonoids, alkaloids, sterols, pigments, unsaturated fatty-acids, micronutrient vitamins and minerals, including vitamin A, B6, B12, C, D, E, and folate, and trace elements, including zinc, iron, selenium, magnesium, and copper. Foods with antiviral properties include fruits, vegetables, fermented foods and probiotics, olive oil, fish, nuts and seeds, herbs, roots, fungi, amino acids, peptides, and cyclotides. Regular moderate exercise may contribute to reduce viral risk and enhance sleep quality during quarantine, in combination with appropriate dietary habits and functional foods. Lifestyle and appropriate nutrition with functional compounds may offer further antiviral approaches for public health.