Reduced Sun Exposure Research Articles

Disentangling Multiple Sclerosis heterogeneity in the French territory among genetic and environmental factors via Bayesian heritability analysis

BackgroundThis study aimed to investigate the factors contributing to the variability of Multiple Sclerosis (MS) among individuals born and residing in France. Geographical variation in MS prevalence was observed in France, but the role of genetic and environmental factors in explaining this heterogeneity has not been yet elucidated. MethodsWe employed a heritability analysis on a cohort of 403 trios with an MS-affected proband in the French population. This sample was retrieved from REFGENSEP register of MS cases collected in 23 French hospital centers from 1992 to 2017. Our objective was to quantify the proportion of MS liability variability explained by genetic variability, sex, shared environment effects, region of birth and year of birth. We further considered gene x environment (GxE) interaction effects between genetic variability and region of birth. We have implemented a Bayesian liability threshold model to obtain posterior distributions for the parameters of interest adjusting for ascertainment bias. ResultsOur analysis revealed that GxE interaction effects between genetic variability and region of birth represent the primary significant explanatory factor for MS liability variability in French individuals (29 % [95 %CI: 5 %; 53 %]), suggesting that additive genetic effects are modified by environmental factors associated to the region of birth. The individual contributions of genetic variability and region of birth explained, respectively, ≈15 % and ≈16 % of MS variability, highlighting a significantly higher MS liability in individuals born in the Northern regions compared to the Southern region. Overall, the joint contribution of genetic variability, region of birth, and their interaction was then estimated to explain 65 % [95 %CI: 35 %; 92 %] of MS liability variability. The remaining proportion of MS variability is attributed to environmental exposures associated with the year of birth, shared within the same household, and specific to individuals. ConclusionOverall, our analysis highlighted the interaction between genetic variability and environmental exposures linked to the region of birth as the main factor explaining MS variability within individuals born and residing in France. Among the environmental exposures prevalent in the Northern regions, and potentially interacting with genetic variability, lower vitamin D levels due to reduced sun exposure, higher obesity prevalence and higher pollution levels represent the main risk factors in influencing MS risk. These findings emphasize the importance of accounting for environmental factors linked to geographical location in the investigation of MS risk factors, as well as to further explore the influence of GxE interactions in modifying genetic risk.

Terroir Dynamics: Impact of Vineyard and Canopy Treatment with Chitosan on Anthocyanins, Phenolics, and Volatile and Sensory Profiles of Pinot Noir Wines from South Tyrol.

The effects of canopy treatment with chitosan and the effects of the vineyard location on the quality parameters, volatile and non-volatile profiles, and sensory profile of Pinot Noir wines from South Tyrol (Italy) were studied. Multivariate statistical analysis was applied to identify the most relevant compounds associated with the variability in phenolics and anthocyanins (analyzed by UHPLC-MS), volatile components (HS-SPME-GCxGC-ToF/MS), and basic enological parameters. A clear separation of low-altitude wines (350 m.a.s.l.), which had a high concentration of most of the identified volatile compounds, compared to high-altitude wines (800 and 1050-1150 m.a.s.l.) was pointed out. Low altitude minimized the concentration of the most significant anthocyanins in wines from a valley bottom, presumably due to reduced sun exposure. Wines obtained from chitosan-treated canopies, and, more particularly, those subjected to multiple treatments per year showed a higher amount of the main non-volatile phenolics and were sensorially described as having "unpleasant flavors" and "odors", which might suggest that grape metabolism is slightly altered compared to untreated grapevines. Thus, optimization of the treatment with chitosan should be further investigated.

A2 UVB ON SKIN EXPOSURE MODULATES INTESTINAL HOMEOSTASIS IN MICE

Abstract Background Inflammatory diseases, like IBD, are on the rise in Western societies, in concert with changes in the environment, such as reduced sun exposure. Ultraviolet light (UV) B's effects on the skin include upregulating vitamin D and Aryl hydrocarbon receptor (Ahr) signalling, but its potential influence on distant sites, like the gut, are not well-studied. The gut and skin share a strong link, with some GI patients also experiencing skin diseases (O’Neill et al., 2016). We sought to understand how UVB exposure affects gut health, gut microbiota and its metabolic by-products. We hypothesize that UVB will have a significant impact on gut health. Aims Test the effect of UVB light using vitamin D deficient (-) and sufficient (+) diets. Elucidate Ahr activation in the small intestine and colon after UVB exposure. Explore the gut metabolome after UVB exposure. Methods Female C57BL/6 mice were fed vit D (+) or (-) diets, anaesthetized, and then 8 cm2 of their dorsal skin was shaved and exposed to UVB (250 mJ/cm2, 234 sec, 311 nm). One single dose (sample collection after 4 or 10 h) or chronic dosage (9 days every other day). Mice were euthanized to collect serum, cecal content, and stool samples (HILIC negative profile and 16S sequencing). EROD assay was used to test Ahr activation of CYP1A1. Results UVB exposure did not cause skin inflammation, but instead induced photoadaptation. When mice with vit D (-) diets were exposed to UVB, their vit D levels rose to match those on vit D (+) diets. Intestinal luminal contents induced a significant 3X increase in Ahr activation at 10 h post-exposure. After chronic UVB exposure, Ahr/CYP1A1 activity increased in Peyer’s patches (p=0.0012) and colon (p=0.01). Serum levels of AhR agonist metabolites post-UVB exposure showed significant increases in kynurenine and indole-3-acetic acid (IAA) at 10 h, while in the feces, Tryptophan levels decreased (p=0.042), but IAA significantly increased (p=0.006). IAA is a known Ahr ligand and produced by gut microbiota when they metabolize Tryptophan, indicating a microbiota response to UVB skin exposure. This was accompanied by an increase in the short chain fatty acids (butyrate, propionate, acetic acid) as well as other metabolites, despite no overt changes in microbiota composition. After 9 days of UVB, significantly increased numbers of goblet cells/crypt in both the ileum and colon. Conclusions Our study demonstrates that UVB exposure on the skin leads to increased vitamin D serum levels and Ahr activation along the gastrointestinal tract. It also induces potentially beneficial metabolic changes in the gut microbiota and differentiation of the gut epithelium, highlighting sun exposure's potential intestinal health benefits. Funding Agencies CCC, CIHR, None

The Relationship between Occupation and Serum Vitamin D Levels in Females during Summer in Sindh, Pakistan

Vitamin D deficiency is a considerable public health issue affecting predominantly South Asians. Objective: To determine the vitamin D levels in females related to different occupations during summer in Sindh, Pakistan. Methods: A comparative cross-sectional study was performed at Liaquat University of Medical and Health Sciences, Jamshoro. Healthy females (n = 236) were recruited according to different occupations into four groups: outdoor workers, office workers, students, and housewives. Results: Overall, 43.6% were vitamin D deficient, 28.9% were vitamin D insufficient, and 27.5% of females had sufficient vitamin D levels. Hypovitaminosis D was highly prevalent in housewives (62.7%) compared to outdoor workers (16.9%). In general, the mean vitamin D of all examined groups was found to be less than the optimal level, and significant differences were noted between occupational groups. Conclusions: The results showed that hypovitaminosis D is prevalent among Pakistani females. Moreover, occupations associated with reduced sun exposure may pose an added risk.

The possible impact of COVID-19 pandemic on serum vitamin D levels on newborns in Greece

Background: Very few studies have evaluated the probable role of the period of 2019 coronovirus disease (COVID-19) pandemic on neonatal 25(OH)D levels. Vitamin D status in the fetus and newborn is largely determined by the vitamin D status of the mother. A recent study in Greece witnessed an unexpected rise in maternal 25(OH)D levels in pregnancy during the COVID-19 period. Consequently, it remains unclear whether neonatal 25(OH)D levels decreased due to reduced sun exposure in the COVID-19 period or followed their unexpected maternal findings. Methods: We studied neonatal 25(OH)D levels in cord blood specimens at birth in 246 neonates of Greek mothers with stratified random sampling, from September 2019 to January 2022. We divided our samples into the pre-COVID-19 period and the post-COVID-19 period. Chi-square test was used to find an association between neonatal 25(OH)D concentrations throughout the COVID-19 period. Quantitative results of 25(OH)D vitamin levels on newborns were transformed into qualitative variables assessing lack of 25(OH)D, adequacy, deficiency and severe deficiency and thus defined in that way. All other results of 25(OH)D levels are presented as means ± standard deviations (SD) or by frequencies and percentages. Results: The results in neonates exhibited a similar pattern to that of their mothers’. The mean serum values of 25(OH)D levels of the newborns were statistically significantly higher during the COVID-19 period compared to the pre-COVID-19 period. Conclusions: Although during the COVID-19 period lower maternal and therefore neonatal 25(OH)D levels were expected, these were higher and because of these findings, we can only make assumptions. Without a doubt, further investigation is required.

Forest islands in farmland provide vital roost trees year-round for giant and common noctule bats: Management implications

Forest islands in agricultural landscapes may be vital for biodiversity conservation, providing habitats for a variety of species, including bats. Our study focused on a forest island in NE Italy, where we observed mixed-species groups of giant (Nyctalus lasiopterus) and common (Nyctalus noctula) noctules roosting at the site. The giant noctule is highly endangered across Europe, and our findings shed light on its roosting preferences, providing key information to inform sustainable forestry practices that take this species into account. Using photographic methods and direct observation, we established that both common and giant noctules occur year-round in the forest island, with giant noctules giving birth, hibernating, and probably mating there. The bats preferred aspen trees and trees rich in cavities with high canopy closure and reduced sun exposure found in the forest interior, while they avoided forest edges. Rot cavities were frequently used, but we found no selection for cavity type, entrance height, or aspect. Despite the common belief that forestry activities in winter have negligible impact on bats, the felling of roost trees during this time can result in significant bat mortality since both common and giant noctules use these trees for hibernation. The number of cavities in a tree is a reliable predictor of a noctule roost, so it is advisable, year-round, to protect trees with cavities. Sustainable forestry practices should incorporate measures to provide roosting opportunities for bats, especially noctules. Our study only pertains to a single forest fragment. While our findings are novel and informative and highlight the conservation value of the forest island we studied, at this stage, they should not be generalized to all forest islands. We, therefore, encourage further large-scale studies to determine whether other forest islands are used similarly and to assess the broad-scale conservation implications of our work, particularly for threatened species such as the giant noctule.

Vitamin D: determinants of status, indications for testing and knowledge in a convenience sample of Irish adults.

Vitamin D deficiency is common in Irish adults, though there is limited research on its determinants, knowledge of vitamin D or indications for testing. We aimed to explore the determinants of vitamin D status in adults and examine knowledge and reasons for testing. The study population comprised adults who had serum 25-hydroxyvitamin D tested by general practitioners request at a Dublin Hospital in 2020. Questionnaires detailing dietary intake, sun exposure, ethnicity, biophysical factors and vitamin D knowledge were sent to a sample stratified by age, sex and vitamin D status. In total, there were 383 participants, mean age 56·0 (sd 16·6) years. Wintertime deficiency disproportionally affected non-white v. white (60 % v. 24 %, P < 0·001). The greatest predictors of deficiency were low vitamin D intake (< 10 μg/d) (P < 0·001) and non-white ethnicity (P = 0·006), followed by sun avoidance (P = 0·022). It was also more prevalent in those with lower body exposure when outdoors. The majority (86 %) identified vitamin D as important for bone health. However, 40 % were tested for non-clinical indications and half were not aware of the recommended daily allowance (RDA). Low vitamin D intake was the most important determinant of deficiency, but ethnicity and sun exposure habits were also significant predictors. The majority had no clear indication for testing and were not aware of the RDA. Public health policies to improve knowledge and vitamin D intake, especially for those of non-white ethnicity and with reduced sun exposure, should be considered.

Vitamin D in the older population: a consensus statement.

BackgroundThis paper reports results from the 5th International Conference “Controversies in Vitamin D” that was held in Stresa, Italy, 15–18 September 2021. The conference is part of this series that started in 2017 and has been conducted annually since. The objective of these conferences is to identify timely and controversial topics related to Vitamin D. Dissemination of the results of the conference through publications in peer-reviewed journals is an important means by which the most up to date information can be shared with physicians, investigators, and other health care professionals. Vitamin D and aging, the subject of this paper was featured at the conference.MethodsParticipants were selected to review available literature on assigned topics related to vitamin D and aging and to present their findings with illustrative material, the intent of which was to stimulate discussion and to arrive at a consensus. The presentations were directed towards the following areas: impact of aging on vitamin D production and levels; skeletal effects of vitamin D deficiency in the older population; falls and vitamin D in the aging; potential extra skeletal effects of vitamin D; and strategies to prevent vitamin D deficiency. A final topic was related to how vitamin D might influence the efficacy of vaccines for Covid-19.ResultsHypovitaminosis D can lead to several skeletal and extra-skeletal outcomes. Older adults are at risk for vitamin D deficiency as both production and metabolism of vitamin D change with aging due to factors, such as reduced sun exposure and reduced production capacity of the skin. Skeletal consequences of these age-related changes can include reduced bone mineral density, osteomalacia and fractures. Potential extra-skeletal effects can include added risks for falls, reduced muscle strength, diabetes, cancer, and cardiovascular disease. Strategies to avoid these vitamin D deficiency-related negative outcomes include sun exposure, food fortification, and supplementation. While aging does not diminish sufficient reserve capacity for cutaneous vitamin D production, concerns about skin cancers and practical matters for the institutionalized elderly limit this option. Supplementation with vitamin D is the best option either pharmacologically or through food fortification. Regardless of treatment strategies, interventions to restore sufficient vitamin D status will show positive results only in those who are truly deficient. Thus, treatment goals should focus on avoiding 25(OH)D serum levels <30 nmol/l, with a goal to reach levels >50 nmol/l.ConclusionsThe results of this conference has led to consensus on several issues. Vitamin D supplementation should be combined with calcium to reduce fractures in the older population. The goal for adequate Vitamin D status should be to reach a serum level of 25(OH)D >50 nmol/l. It appears that daily low-dose vitamin D regimens reduce the risk of falling, especially in the elderly, compared with infrequent, large bolus doses that may increase it. The role of Vitamin D supplementation on muscle strength remains to be clarified. On the other hand, supplementation decreases the risk of progression to T2D from prediabetes among those who are Vitamin Ddeficient. Of three possible strategies to establish vitamin D sufficiency – sunshine exposure, food fortification, and supplementation – the latter seems to be the most effective and practical in the aging population.

Bone\xa0metabolism in patients with type 1 neurofibromatosis: key role of sun exposure and physical activity

Bone metabolism has been rarely investigated in children affected by Neurofibromatosis type 1 (NF1). Aim of the present study was to assess bone mineral metabolism in children and adults NF1 patients, to determine the relevant factors potentially involved in the development of reduced bone mineral density (BMD), and provide possible therapeutic intervention in NF1 patients. 114 NF1 patients and sex and age matched controls were enrolled into the study. Clinical and biochemical factors reflecting bone metabolism were evaluated. Factors potentially affecting BMD were also investigated including: physical activity, sun exposure, vitamin D intake. Whenever the presence of vitamin D deficiency was recorded, cholecalciferol supplementation was started and z-score data obtained at Dual-Energy X-ray Absorptiometry (DXA) during supplementation were compared with previous ones. NF1 patients showed lower Z-scores at Dual-Energy X-ray Absorptiometry DXA than controls. Physical activity was significantly reduced in NF1 patients than in controls. Sun exposure was significantly lower in NF1 compared to control subjects. At linear regression analysis vitamin D was the most predictive factor of reduced z-score at DXA (p = 0.0001). Cholecalciferol supplementation significantly increased BMD z-score (p < 0.001). We speculated that a combination of different factors, including reduced sun exposure, possibly associated with reduced serum vitamin D levels, and poor physical activity, concur to the impaired bone status in NF1 patients. We also demonstrated that treatment with vitamin D can be effective in improving z-score value in NF1 patients, including children. In conclusion, the findings of the current study are expected to have important implications for the follow-up and prevention of osteopenia/osteoporosis in this common genetic disease.

Walking on sunshine! Vitamin D in psychiatric inpatients

AimsWe aimed to determine whether vitamin D is being tested on admission for psychiatric inpatients at a local inpatient hospital, to identify the level of vitamin D for this group and to establish whether vitamin D treatment provided is according to NICE guidance.Emerging evidence suggests that psychiatric patients are more vulnerable to vitamin D deficiency, due to reduced sun exposure, social isolation, long inpatient stays and poor diet. Low vitamin D levels may also increase susceptibility to SARS CoV-2 infection and COVID-19 severity.MethodStandards were determined by local policies, RCPsych recommendations and NICE guidance. Data were collected retrospectively from electronic patient records and entered manually to a spreadsheet for analysis.Result67% of patients had vitamin D tested on admission to hospital. Of the patients that had their vitamin D level tested, 39% patients had their result recorded. 48% either had a low vitamin D level or required replacement. 6 of 12 patients with a documented low vitamin D level had the correct vitamin D treatment, according to NICE guidance.ConclusionOf 46 patient records, nearly half had a documented low vitamin D level or were on treatment. We would therefore suggest that vitamin D testing should form part of the routine admission bloods. It is an important opportunity to detect deficiency or insufficiency for a potentially vulnerable group of patients. Intervention is simple and effective.Results demonstrated room for improvement for vitamin D testing on admission to hospital, thus improving potential treatment and benefits for individual patients. The importance of recording blood results on to the electronic patient record was also highlighted.We raised awareness and provided further education to all junior doctors, with creative posters and informative communications. Following the implementation of these changes a re-audit of 40 patients showed 75% had vitamin D tested on admission or during and of these, 58% either had a low vitamin D level or required replacement. 7 of 9 patients with a documented low vitamin D level had the correct vitamin D treatment, according to NICE guidance. Within this closed loop audit, we have reported moderate improvement in the testing of vitamin D for patients on admission to hospital along with a significant improvement in the treatment of vitamin D deficiency, according to NICE guidance.

Endocrinological disorders and inflammatory skin diseases during COVID-19 outbreak: a review of the literature

In the next future, dermatologists, endocrinologist and physicians may cope with the impact of extent SARS-CoV-2 (COVID-19) infection over chronic inflammatory skin diseases and their treatment. COVID-19 pandemic obliged many countries to impose social restrictions, resulting in the need to adapt daily lifestyle habits and working activities. These changes have drastically reduced physical activity and social interactions, with the possible increase of anxiety, eating disorders and weight gain. We searched for relevant studies (trials, real-life studies and case reports, meta-analysis, pooled data analysis, reviews) on endocrine disorders and inflammatory skin diseases. The database used was PubMed. The studies included were those published in the English language between January 1, 2018 and May 5, 2020. Several studies have been previously showed the association of overweight and obesity, with the metabolic syndrome and insulin-resistance. It has been demonstrated how these conditions correlate with the worsening of such chronic inflammatory skin diseases, such as psoriasis, hidradenitis suppurativa and acne. Many evidences suggest an important role of adipose tissue in the production of pro-inflammatory cytokines (Leptin, adiponectin, TNFα, IL-6, MCP-1, PAI-1), involved in the pathogenesis and the exacerbations of these skin diseases. In addition, we should expect an increasing incidence rate of hypovitaminosis D in the next future due to reduced sun exposure caused by isolation at home and missed holidays. Scientific evidences already show the important immunomodulating role of vitamin D in inflammatory skin diseases. Our study pays attention on medium-long term effects of COVID-19 outbreak on inflammatory skin disorders, due to the lifestyle changes. In such context this review considers how a multidisciplinary approach, involving dermatologists, nutritionists and endocrinologists, may lead to a better management of dermatologic patients.

Vitamin D in pediatric health and disease.

Several scientific societies established that vitamin D (VD), in its metabolized form 25(OH)D, levels higher than 20ng/mL are sufficient to ensure optimal bone health, while 25(OH)D levels higher than 30ng/mL are needed to favor VD extraskeletal actions. However, it has been estimated that approximately 30% of children and 60% of adults worldwide are VD deficient and insufficient, respectively. This is the reason why it is important to provide a practical approach to VD supplementation for infants, children, and adolescents. It is the pediatrician's role to evaluate the modifiable lifestyle risk factors for deficiency, particularly a reduced sun exposure, following an evidence-based approach, and to suggest VD supplementation only when there is a rational reason to support its use.

Nutritional rickets & osteomalacia: A practical approach to management.

Defective mineralization of the growth plate and preformed osteoid result in rickets and osteomalacia, respectively. The leading cause of rickets worldwide is solar vitamin D deficiency and/or dietary calcium deficiency collectively termed as nutritional rickets. Vitamin D deficiency predominates in high-latitude countries in at-risk groups (dark skin, reduced sun exposure, infants and pregnant and lactating women) but is emerging in some tropical countries due to sun avoidance behaviour. Calcium deficiency predominates in tropical countries, especially in the malnourished population. Nutritional rickets can have devastating health consequences beyond bony deformities (swollen wrist and ankle joints, rachitic rosary, soft skull, stunting and bowing) and include life-threatening hypocalcaemic complications of seizures and, in infancy, heart failure due to dilated cardiomyopathy. In children, diagnosis of rickets (always associated with osteomalacia) is confirmed on radiographs (cupping and flaring of metaphyses) and should be suspected in high risk individuals with the above clinical manifestations in the presence of abnormal blood biochemistry (high alkaline phosphatase and parathyroid hormone, low 25-hydroxyvitamin D and calcium and/or low phosphate). In adults or adolescents with closed growth plates, osteomalacia presents with non-specific symptoms (fatigue, malaise and muscle weakness) and abnormal blood biochemistry, but only in extreme cases, it is associated with radiographic findings of Looser's zone fractures. Bone biopsies could confirm osteomalacia at earlier disease stages, for definitive diagnosis. Treatment includes high-dose cholecalciferol or ergocalciferol daily for a minimum of 12 wk or stoss therapy in exceptional circumstances, each followed by lifelong maintenance supplementation. In addition, adequate calcium intake through diet or supplementation should be ensured. Preventative approaches should be tailored to the population needs and incorporate multiple strategies including targeted vitamin D supplementation of at-risk groups and food fortification with vitamin D and/or calcium. Economically, food fortification is certainly the most cost-effective way forward.

The relationship between Vitamin D and depressive disorders.

Studies have suggested a relationship between low circulating levels of Vitamin D and depression. Vitamin D deficiency may be a consequence of depression-related factors, such as reduced sun exposure, decreased outdoor activity, and dietary changes, but it can also play a role in the pathophysiology of depressive conditions through a range of molecular mechanisms. In the present manuscript, findings related to prospective longitudinal studies on the relationship between Vitamin D levels and depressive symptoms and to randomized controlled trials on Vitamin D supplementation for depressive disorders are reviewed.

Trabecular Bone Score (TBS) and Bone Metabolism in Patients Affected with Type 1 Neurofibromatosis (NF1)

In patients with neurofibromatosis type 1 (NF1), decreased bone mineral density (BMD) and low levels of 25-hydroxy vitamin D3 (25OHD) have been reported. Recently, the trabecular bone score (TBS) measurement has been proposed as index of bone microarchitecture and fracture risk. In 74 NF1 patients (48 females, 26 males, age 41 ± 12), we measured TBS and investigated clinical stage, lifestyle, vitamin D, serum bone turnover markers, vertebral and femoral BMD. A homogenous cohort of 61 healthy subjects was used as control group. TBS was lower in NF1 patients (1.266 ± 0.113 vs. 1.346 ± 0.105) without differences between sexes. No correlations with 25OHD, low exercise, low calcium intake, reduced sun exposure, and number of skin neurofibromas were observed. As expected, hypovitaminosis D was common (98.6%), as well as BMD reduction in hip and spine sites: In NF1 patients, bone texture evaluated by TBS was low in both sexes without any correlation with clinical or metabolic parameters, suggesting a direct role of the fibromin mutation.

The battle over indoor tanning heats up: Despite some recent gains, reducing the risk of a known carcinogen will require far more than good science.

The battle over indoor tanning heats up: Despite some recent gains, reducing the risk of a known carcinogen will require far more than good science.

The prevalence of vitamin D deficiency-insufficiency in medical faculty students

Aim: The vitamin D deficiency is a pandemic health problem due to worldwide modernization. We tried to determine the impact of the reduced sun exposure on the vitamin D levels of the medical faculty students due to the long study hours and indoor study environment and classrooms. Material and Method: Two-hundred and eleven (113 women, 98 men) medical faculty students were included in the study. Blood samples were obtained from the students and serum 25 hydroxyvitamin D3 levels were measured on the same day. Students were healthy individuals, aged 17-29 years (mean age= 19 years). Data were analyzed using SPSS software program. The frequency distribution of the qualitative data and arithmetic mean, minimum, maximum and standard deviation of the quantitative data were used to define descriptive statistics. Non-parametric tests and Chi-square test were used for the analysis of qualitative data; the analysis of the quantitative data was done by observing normally distributed data. The significance level of Chi-square test, independent-student t-test and Mann-Whitney U test were accepted as p≤0.05. Results: Serum 25 hydroxyvitamin D3 levels was below 20 ng/ml in 56% (n=118) of the students, of which 72% (n=85) were women. Conclusion: Especially, women had high levels of vitamin D deficiency in our study. This high ratio gives rise to thought that women spend more of their time indoor spaces due to modernization., women are exposed to sun light less than men, and thus they have higher levels of vitamin D deficiency.

Vitamin D in European children-statement from the European Academy of Paediatrics (EAP).

Vitamin D is synthesized in human skin upon sun exposure and is also a nutrient. It regulates calcium and phosphate metabolism and is essential for the maintenance of bone health. Vitamin D supplementation during infancy, in order to prevent rickets, is universally accepted. Many human cell types carry vitamin D receptor, this being a drive for conducting studies on the possible association between vitamin D status and other diseases. Studies have affirmed that a considerable number of healthy European children may be vitamin D deficient, especially in high-risk groups (darker pigmented skin, living in areas with reduced sun exposure and other disorders). However, the definition of deficiency is unclear due to inter assay differences and due to a lack of consensus as to what is an "adequate" 25(OH)D level. Therefore, there is no justification for routine screening for vitamin D deficiency in healthy children. An evaluation of vitamin D status is justified in children belonging to high-risk groups. All infants up to 1year of age should receive an oral supplementation of 400IU/day of vitamin D. Beyond this age, seasonal variation of sunlight should be taken into account when considering a national policy of supplementation or fortification.

Reconnoitering the relationship between “the sunshine Vitamin” and periodontal disease

According to anthropological records, with a reduction in dietary intake of Vitamin D and reduced sun exposure, the prevalence of Vitamin D deficiency is increasing day by day. About 30%–50% of the general adult population has serum Vitamin D levels below the recommended values. Since its discovery of Vitamin D is always associated with regulation of calcium metabolism. Recently, it has been discovered that Vitamin D plays a role beyond this. Numerous evidences have indicated that the participants with Vitamin D deficiency are at a higher risk of bone loss, but they are also prone to many infectious and chronic inflammatory diseases. Through its effect on bone and mineral metabolism, innate immunity, and several Vitamin D receptor gene polymorphisms, it is now believed that Vitamin D benefits periodontal health and its deficiency is associated with the periodontal disease. This review will examine these actions of Vitamin D, in particular, the role of Vitamin D in periodontal diseases.

The Effects of Physical Activity and Sun Exposure on Vitamin D Status among Children from Jeddah, Saudi Arabia

Background: The prevalence of vitamin D deficiency has increased among children and adults during the past decade. This study aimed to determine whether physical activity and sun exposure affected vitamin D status among healthy Saudi children. Methods: This cross-sectional study included 378 Saudi children (187 girls and 191 boys) who were 4-18 years old. Their levels of physical activity and sun exposure were estimated using a questionnaire, and blood samples were obtained to analyze their vitamin D levels. Results: We found that 371 children (98.1%) had low vitamin D levels and 7 children (1.9%) had normal levels. Children who exercised >3 times/week had higher levels of vitamin D, compared to less active children. Children who exposed the greatest number of body parts had higher vitamin D levels, compared to children who only exposed their face, hand and arms, or face. There was no correlation between low vitamin D levels and sex (deficiency: 185 girls [48.9%] and 186 boys [49.2%]). Conclusion: Otherwise healthy children exhibited a high prevalence of vitamin D deficiency, which may be related to reduced sun exposure and physical activity. Therefore, vitamin D supplementation may be appropriate for children who have a high risk of deficiency.