Cutaneous vitamin D synthesis versus skin cancer development: The Janus faces of solar UV-radiation

Cross-sectional study protocol to assess ultraviolet radiation exposure among military outdoor workers in Lohatla, Northern Cape Province of South Africa

INTRODUCTION

The sun is one of the primary natural sources of ultraviolet radiation (UVR) and a known human carcinogen. It has been related to melanoma and several skin cancers, such as squamous cell carcinoma and basal cell carcinoma. Non-melanoma skin cancers are prevalent in South Africa, with high reported incidence rates in both genders. Due to its diversified population, South Africa experiences extreme ultraviolet index (UVI) levels, reaching 13 in the summer (a UVI of 11+ is considered extreme). Most summer workdays expose outdoor workers to repeated UVR exposure, which can lead to health risks like sunburn, premature ageing, cataracts, and an increased risk of skin cancer. This study aims to evaluate UV radiation exposure among outdoor military workers.

METHODS AND ANALYSIS

A cross-sectional quantitative study will occur at the Lohatla military base in Kathu, Northern Cape province of South Africa, using personal electronic dosimeters for solar UVR assessment. Additionally, a self-administered questionnaire will assist in assessing health effects and perceived exposure behaviours. The study addresses a critical public health concern, exploring significant risks associated with UVR exposure among outdoor military workers across different demographics.

ETHICS AND DISSEMINATION

The ethical approval for this study was obtained from the Health Sciences Research Committees of the University of Free State (UFS-HSD2023/1227/2811). The confidential data will be accessed by the named researchers and stored in secure password-protected platforms. In addition, the findings will be disseminated through high-impact publications in various formats to government departments and the broader scientific community.

Highly bioactive triple-helical nano collagens for accelerated treatment of photodamaged skin

Skin damage caused by excessive UV exposure has gradually become one of the most common skin diseases, leading to desquamation, scab formation, inflammation and even skin cancer. Animal-derived hydrolyzed collagen peptides have been developed to treat UV-damaged skin; however, they have raised severe concerns such as potential viral transmission, random sequences and the lack of a triple helix structure. Nano collagen, a novel type of short collagen, has attracted increasing attention in the mimicking of natural collagen, while its applications in UV-damaged skin treatment remains unexplored. Herein, we have created a series of nano collagens and for the first time studied their capability of accelerating UV-damaged skin healing. Nano collagens, consisting of repetitive (GPO)n triplets and a GFOGER motif, display a stable triple-helical structure, significantly promoting fibroblast adhesion, proliferation, and migration. The repair effects of nano collagens have been investigated using an acute UV-damaged skin mouse model. Combo evaluations indicate that nano collagens contribute to recovering the dermis density and erythema index of UV-damaged skin. Histological analysis further demonstrates their capability of promoting the healing of damaged skin by accelerating re-epithelialization and collagen regeneration. These highly bioactive triple-helical nano collagens present a novel strategy for the treatment of UV-damaged skin, providing promising applications in cosmetics and dermatology.

Photoinduced skin reactions of cardiovascular drugs-a systematic review

This systemic review aims to provide a practical overview of the prevalence, clinical manifestation, and management of adverse photoinduced skin reactions caused by frequently used cardiovascular drugs and to assess their potential relevance for skin cancer development. Data search included PubMed, Web of Science, and the Cochrane Library. A systematic review of peer-reviewed studies reporting the photosensitizing and/or skin cancer-inducing properties of common cardiovascular drugs was performed and a guide to clinical management of photoinduced skin eruptions by cardiovascular drugs was provided. Study quality was assessed for major methodological biases. A total of 58 studies were identified (i.e. 23 case reports, 14 observational studies, 10 review articles, 10 experimental studies, and 1 meta-analysis). Most commonly, drug-associated adverse photoinduced cutaneous reactions were caused by phototoxic and photoallergic mechanisms. There is evidence suggesting that amiodarone and dronedarone, thiazide diuretics, thiazide-like diuretics, angiotensin receptor blockers, dihydropyridine-type calcium channel blockers, and certain angiotensin-converting enzyme inhibitors and statins may cause photoinduced adverse cutaneous reactions. Other drugs such as anticoagulants, antiplatelets, aldosterone antagonists, and fibrates have not been linked with photosensitizing reactions or adverse cutaneous reactions. Some drugs, i.e. thiazides and thiazide-like diuretics, were associated with an increased risk of non-melanoma skin cancers (basal cell carcinoma and squamous cell carcinoma). Certain commonly used cardiovascular drugs have been associated with adverse photoinduced cutaneous reactions. If they occur, further diagnosis and treatment might be needed, depending on the severity and progress. Whether photosensitizing drugs increase the risk of skin cancer remains elusive and further randomized controlled trials are required.

Ozone Layer Depletion and Emerging Public Health Concerns - An Update on Epidemiological Perspective of the Ambivalent Effects of Ultraviolet Radiation Exposure

Solar ultraviolet (UV) radiation exposure is the primary etiological agent responsible for developing cutaneous malignancies. Avoiding excessive radiation exposure, especially by high-risk groups, is recommended to prevent UV-induced photo-pathologies. However, optimal sun exposure is essential for the healthy synthesis of about 90% of vitamin D levels in the body. Insufficient exposure to UV-B is linked to vitamin D deficiency in humans. Therefore, optimal sun exposure is necessary for maintaining a normal state of homeostasis in the skin. Humans worldwide face a major existential threat because of climate change which has already shown its effects in several ways. Over the last 4 to 5 decades, increased incidences in skin cancer cases have led international health organizations to develop strong sun protection measures. However, at the same time, a growing concern about vitamin D deficiency is creating a kind of exposure dilemma. Current knowledge of UV exposure to skin outweighs the adverse effects than the beneficial roles it offers to the body, necessitating a correct public health recommendation on optimal sun exposure. Following an appropriate recommendation on optimal sun exposure will lead to positive outcomes in protecting humans against the adverse effects of strict recommendations on sun protection measures. In this short review, we spotlight the ambivalent health effects of UV exposure and how ozone layer depletion has influenced these effects of UVR. Further, our aim remains to explore how to lead towards a balanced recommendation on sun protection measures to prevent the spurt of diseases due to inadequate exposure to UV-B.

Moderate Sun Exposure Is the Complementor in Insufficient Vitamin D Consumers

Background and Aims

Vitamin (Vit) D plays a vital role in human health, and the prevalence of Vit D deficiency worldwide has been a rising concern. This study investigates the serum 25-hydroxy-Vit D [25(OH)D] status in healthy US civilians and identifies how the two main sources, sun exposure and dietary Vit D intake, determine the final 25(OH)D levels in individuals.

Methods

A total of 2,360 of participants from The National Health and Nutrition Examination Survey (NHANES) 2009–2014 were analyzed. We divided the levels of sun exposure and dietary Vit D intake of all subjects into 10 strata and gave a score ranging from 1 to 10 points, respectively. Scores 1–5 in sun exposure and dietary intake were considered as relatively low exposure groups, whereas scores 6–10 were considered as relatively high exposure groups. Serum Vit D inadequacy was defined as <50 nmol/L. Linear and logistic regression analyses were used to examine the associations between sources of Vit D and serum 25(OH)D levels.

Results

In relatively low Vit D intake groups (Vit D intake score 1–5), relatively high sun exposure (sun exposure score >5) resulted in higher serum 25(OH)D levels (average 57 nmol/L) compared with relatively low sun exposure (sun exposure score <5) (average 50 nmol/L), whereas this difference became negligible in high intake groups (Vit D intake score 6–10). Moreover, the greatest slope occurred in the low Vit D intake curve (decile 3 of Vit D intake), which shows increased sun exposure time causing the greatest degree of change in serum 25(OH)D level in this group.

Conclusion

Sun exposure can significantly make up for deficiencies in subjects who consume insufficient dietary Vit D. Compared with the extra cost and time for building habits of Vit D supplementation, moderate sun exposure appears to be a simple and costless means for the public to start in daily practice.

A comparison of the effect of supplementation and sunlight exposure on serum vitamin D and parathyroid hormone: A systematic review and meta-analysis

Background: Supplementation and getting sunlight exposure are two treatments for vitamin D deficiency. However, studies reported conteroversial findings regarding the efficacy of these two methods.Objective: To compare the effect of oral vitamin D supplementation with sunlight exposure on serum vitamin D and parathyroid hormone (PTH).Methods: A computer-based literature search through PubMed, Scopus and Google scholar search engines was conducted until April 2019 to find clinical trials which compared the effect of oral vitamin D supplementation with sunlight exposure on serum vitamin D and PTH. Means for serum 25-hydroxy vitamin D3 (25(OH) D3) and PTH concentration were extracted. A subgroup analysis was used to detect potential sources of inter-study heterogeneity. Mean differences (MD) were analyzed using a random-effects model (the DerSimonian-Laird approach).Results: A total of seven papers were included in the meta-analysis. Pooled analysis showed that vitamin D supplementation significantly elevated levels of serum 25(OH) D3 in comparison with sunlight exposure (MD: 8.56nmol/l, 95%CI: 4.15, 12.97, T² = 40.32%, H² = 9.45%, P for heterogeneity p < 0.001). Also, the difference between the effect of vitamin D supplementation and sun exposure was lower in studies which used UVB radiation compared with studies which applied direct sunlight (MD: 11.65 nmol/l, 95%CI: 7.02, 16.28; P for between subgroup heterogeneity = 0.001).Conclusion: Vitamin D supplementation was more effective than sun exposure at increasing serum 25(OH) D3. The difference between efficacy of vitamin D supplementation and sun exposure was lower in studies which used long-term sun exposure or applied UVB treatment instead of direct sunlight.

Evaluation of vitamin D plasma levels after mild exposure to the sun with photoprotection

BACKGROUND

Most of the organism's vitamin D (VD) is obtained through the cutaneous synthesis after exposure to the sun's UVB radiation. Sunscreens are indicated for the prevention of actinic damage to the skin, however, there are few clinical trials assessing the synthesis of cutaneous VD in real-life situations of sun exposure with ordinary clothing and usual photoprotection.

OBJECTIVES

To evaluate the synthesis of VD with suberythemal sun exposure in healthy adults using topical photoprotection (SPF 30).

METHODS

Quasi-experimental study, conducted at Rio de Janeiro (Brazil), during winter, with 95 healthy adults who had 25-OH-VD checked twice, 24 hours apart, and were exposed to the sun (UVB=20 mJ/cm2), according to a randomized grouping: SC - use of SPF 30 on the face, neck and chest (n=64), NO - no sunscreens (n=10), CO - confined from sun exposure for 24h (n=21). The groups were matched according to the propensity score related to gender, age, phototype, body mass index, glycosylated hemoglobin and baseline levels of VD. The outcome evaluated was the variation (ΔVD) in serum level of 25-OH-VD (ng/ml) between the groups.

RESULTS

A statistically significant difference was identified between CO and SC groups [median (p25-p75)]: ΔVD =1.4 (-0.3-3.6) vs. 5.5 (4.8-6.6); p<0.01. There was no difference between SC and NO groups: 5.4 (3.1-6.1) vs. 4.1 (2.5-6.0); p=0.17.

STUDY LIMITATIONS

Laboratory analysis technique (chemiluminescence) with great variability, loss of food intake standardatization, unbalanced groups.

CONCLUSIONS

Suberythemal sun exposure with sunscreen (SPF 30) provides similar vitamin D serum variation than without photoprotection in healthy adults.

Vegan diets: practical advice for athletes and exercisers

With the growth of social media as a platform to share information, veganism is becoming more visible, and could be becoming more accepted in sports and in the health and fitness industry. However, to date, there appears to be a lack of literature that discusses how to manage vegan diets for athletic purposes. This article attempted to review literature in order to provide recommendations for how to construct a vegan diet for athletes and exercisers. While little data could be found in the sports nutrition literature specifically, it was revealed elsewhere that veganism creates challenges that need to be accounted for when designing a nutritious diet. This included the sufficiency of energy and protein; the adequacy of vitamin B12, iron, zinc, calcium, iodine and vitamin D; and the lack of the long-chain n-3 fatty acids EPA and DHA in most plant-based sources. However, via the strategic management of food and appropriate supplementation, it is the contention of this article that a nutritive vegan diet can be designed to achieve the dietary needs of most athletes satisfactorily. Further, it was suggested here that creatine and β-alanine supplementation might be of particular use to vegan athletes, owing to vegetarian diets promoting lower muscle creatine and lower muscle carnosine levels in consumers. Empirical research is needed to examine the effects of vegan diets in athletic populations however, especially if this movement grows in popularity, to ensure that the health and performance of athletic vegans is optimised in accordance with developments in sports nutrition knowledge.

Short-term UVB irradiation significantly increases vitamin D serum concentration in obese patients: a clinical pilot study

PURPOSE

Deficiency of vitamin D is very common in obese people and treatment by oral supplementation is not effective in all patients. This exploratory pilot study investigated the influence of different doses of short-term ultraviolet B irradiation on serum 25-hydroxyvitamin-D₃ (25D) and 1,25-dihydroxyvitamin-D₃ (1,25D) levels in obese compared to normal weight subjects and obese controls.

METHODS

Participants with skin types II and III (Fitzpatrick skin classification) were assigned to six groups including four intervention groups receiving irradiation (three groups of obese and one group of normal weight subjects) and two control groups without treatment (obese and normal weight). Intervention groups received three sessions of whole body UVB irradiation of three different doses (cumulative doses over three sessions: 0.28, 0.70, 1.75 minimal erythema dose) within 1 week of intervention. Serum 25D and 1,25D were measured at baseline and after irradiation. Outcome differences between groups were analyzed using a linear model.

RESULTS

Serum 25D levels increased significantly in obese (+23.6 and +26.7%, respectively, p = 0.01) and normal weight (+15.6%, p = 0.02) intervention groups who received medium and high doses of ultraviolet B irradiation compared to control groups (+3.5 and -4.0%, respectively, p = 1.0). The increase in obese patients was 51.4% greater compared to normal weight controls irradiated with equal ultraviolet B doses. Low-level ultraviolet irradiation did not result in a significant change in serum 25D (+7.0%, p = 0.61). We did not detect any significant differences of 1,25D between groups (p = 0.25).

CONCLUSIONS

The current study indicates that short-term ultraviolet B irradiation increases 25D levels in obese patients.

Recommendations of the Brazilian Society of Endocrinology and Metabology (SBEM) for the diagnosis and treatment of hypovitaminosis D

OBJECTIVE

The objective is to present an update on the diagnosis and treatment of hypovitaminosis D, based on the most recent scientific evidence.

MATERIALS AND METHODS

The Department of Bone and Mineral Metabolism of the Brazilian Society of Endocrinology and Metabology (SBEM) was invited to generate a document following the rules of the Brazilian Medical Association (AMB) Guidelines Program. Data search was performed using PubMed, Lilacs and SciELO and the evidence was classified in recommendation levels, according to the scientific strength and study type.

CONCLUSION

A scientific update regarding hypovitaminosis D was presented to serve as the basis for the diagnosis and treatment of this condition in Brazil.

Vitamin D as a Resilience Factor, Helpful for Survival of Potentially Fatal Conditions: A Hypothesis Emerging from Recent Findings of the ESTHER Cohort Study and the CHANCES Consortium

There is debate on whether vitamin D deficiency is a risk factor for major chronic diseases and premature death or whether observed associations were just confounded by general health status. Here, we review recent results from the Epidemiologische Studie zu Chancen der Verhütung, Früherkennung und optimierten Therapie chronischer Erkrankungen in der älteren Bevölkerung (ESTHER) cohort study and the Consortium on Heatlh and Ageing: Network of Cohorts from Europe and the United States (CHANCES) that suggest that vitamin D deficiency may not be a risk factor for the development of cardiovascular diseases and cancer but may be a risk factor for fatal instances of these diseases. Furthermore, analyses comprehensively adjusted for the health status showed that the association of vitamin D and mortality was very likely not confounded by general health status. These results suggest that vitamin D could be a marker of resilience to fatality of potentially fatal diseases. Sufficient vitamin D serum concentrations may be needed to regulate the response of the immune system when it is challenged by severe diseases to prevent a fatal course of the disease. If this hypothesis can be verified through basic research studies and adequately designed randomized controlled trials, it could have important public health implications because vitamin D deficiency is very common worldwide, and interventions could be implemented easily.

The role of vitamin D in psoriasis: a review

BACKGROUND AND OBJECTIVE

Psoriasis is a common, chronic autoimmune inflammatory skin disorder, which has potential systemic complications and is clinically defined by sharply demarcated, erythematous patches and plaques covered by a characteristic silvery white scale. Topical corticosteroids have widely been regarded as the mainstay first line of treatment. Recently, topical vitamin D analogs have been added to the first-line treatment repertoire as well, either as monotherapy or in combination with topical steroids due to synergistic, complementary effectiveness. In this paper, we review the role of vitamin D in the pathophysiology and treatment of psoriasis.

METHODS

A comprehensive search of the Cochrane Library, MEDLINE, and PUBMED databases were performed to identify relevant basic science and clinical trial literature investigating the role of vitamin D in psoriasis. Primary endpoints in clinical trials were largely based on clinical improvement as assessed by the psoriasis area severity index score or physician's global assessment.

RESULTS AND CONCLUSION

The role of vitamin D in psoriasis is complex and extensive. Oral and topical vitamin D therapies provide comparable efficacies to corticosteroids when used as monotherapy and may be superior when used in combination with a potent topical steroid. Additionally topical vitamin D analogs demonstrate a favorable safety profile with "steroid-sparing" effects. Thus, topical vitamin D derivatives should be considered an indispensable component of the current physician's arsenal in the treatment of psoriasis.

Influence of external, intrinsic and individual behaviour variables on serum 25(OH)D in a German survey

The objective of the present study was to identify external, intrinsic or behavioural factors that significantly influenced serum 25-hydroxyvitamin D (25(OH)D) concentrations in a German survey. Data from 3061 participants in the Cooperative Health Research in the Region of Augsburg, Germany (KORA) F4 survey were used to relate potential determinants to measured mean serum 25(OH)D concentrations using multivariable regression models. The factors significantly associated with hypovitaminosis D (defined as 25(OH)D<25 nmolL(-1)) were season (winter, spring and autumn), urban environment and high body mass index. In contrast, times spent in sunny regions, hours per day spent outdoors in the summer as well as additional oral intake were associated with higher 25(OH)D concentrations. These results suggest that mainly ambient UV exposure but also individual behaviour are the most important determinants for personal 25(OH)D concentrations. The analyses further showed that in winter 43% of subjects were vitamin D deficient and 42% insufficient. Even in summer over half the population has insufficient vitamin D status with 8% deficient and 47% insufficient. Therefore measures to mitigate widespread vitamin D insufficiency such as regular short-term sun exposure and/or improved dietary intake/supplementation recommendations by public health bodies need to be considered.

Effect of vitamin D supplementation and ultraviolet B exposure on serum 25-hydroxyvitamin D concentrations in healthy volunteers: a randomized, crossover clinical trial

BACKGROUND

Solar ultraviolet (UV) radiation during the summer and vitamin D supplementation are two major sources of vitamin D for humans at northern latitudes. However, little is known about the relative efficiency of these two vitamin D sources.

OBJECTIVES

The main goal was to compare the efficiency of high-dose oral vitamin D3 supplementation (2000 IU per day for 30 days) with a simulated summer UV exposure [10 sunbed sessions to a total dose of 23·8 standard erythema doses (SED)] to improve vitamin D status.

METHODS

Healthy volunteers were randomized into two groups: group 1 received vitamin D supplementation followed by 10 whole-body sunbed exposures; group 2 started with 10 sunbed exposures followed by vitamin D supplementation.

RESULTS

The oral supplementation with vitamin D3 resulted in a mean (SEM) serum 25-hydroxyvitamin D [25(OH)D] increase of 25·3 (5·4) nmol L(-1) . A similar increase, 19·8 (5·4) nmol L(-1) , was observed after simulated summer UV exposure. At the end of the study, serum 25(OH)D concentrations were similar in both groups.

CONCLUSIONS

Twice-weekly whole-body sunbed exposure to a dose of 4·8 SED is equal to 2000 IU daily of oral vitamin D supplementation for 30 days and enough to achieve and maintain serum 25(OH)D concentrations > 75 nmol L(-1) in ~55% of cases. Based on our calculations, this dose corresponds to a cumulative weekly whole-body exposure of 3·4 SED (~ 40 min around midday during the summer at the latitude of Oslo).

Optimal vitamin D status: a critical analysis on the basis of evidence-based medicine

CONTEXT

Public health authorities around the world recommend widely variable supplementation strategies for adults, whereas several professional organizations, including The Endocrine Society, recommend higher supplementation.

METHODS

We analyzed published randomized controlled clinical trials to define the optimal intake or vitamin D status for bone and extraskeletal health.

CONCLUSIONS

The extraskeletal effects of vitamin D are plausible as based on preclinical data and observational studies. However, apart from the beneficial effects of 800 IU/d of vitamin D3 for reduction of falls in the elderly, causality remains yet unproven in randomized controlled trials (RCTs). The greatest risk for cancer, infections, cardiovascular and metabolic diseases is associated with 25-hydroxyvitamin D (25OHD) levels below 20 ng/mL. There is ample evidence from RCTs that calcium and bone homeostasis, estimated from serum 1,25-dihydroxyvitamin D and PTH, calcium absorption, or bone mass, can be normalized by 25OHD levels above 20 ng/mL. Moreover, vitamin D supplementation (800 IU/d) in combination with calcium can reduce fracture incidence by about 20%. Such a dose will bring serum levels of 25OHD above 20 ng/mL in nearly all postmenopausal women. Based on calculations of the metabolic clearance of 25OHD, a daily intake of 500-700 IU of vitamin D3 is sufficient to maintain serum 25OHD levels of 20 ng/mL. Therefore, the recommendations for a daily intake of 1500-2000 IU/d or serum 25OHD levels of 30 ng or higher for all adults or elderly subjects, as suggested by The Endocrine Society Task Force, are premature. Fortunately, ongoing RCTs will help to guide us to solve this important public health question.

UV radiation and the skin

UV radiation (UV) is classified as a "complete carcinogen" because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natural synthesis of vitamin D and endorphins in the skin, therefore UV has complex and mixed effects on human health. Nonetheless, excessive exposure to UV carries profound health risks, including atrophy, pigmentary changes, wrinkling and malignancy. UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma, which together affect more than a million Americans annually. Genetic factors also influence risk of UV-mediated skin disease. Polymorphisms of the melanocortin 1 receptor (MC1R) gene, in particular, correlate with fairness of skin, UV sensitivity, and enhanced cancer risk. We are interested in developing UV-protective approaches based on a detailed understanding of molecular events that occur after UV exposure, focusing particularly on epidermal melanization and the role of the MC1R in genome maintenance.

Serum 25-hydroxyvitamin D levels and overall mortality. A systematic review and meta-analysis of prospective cohort studies

OBJECTIVE

To provide a systematic review and meta-analysis of prospective, population-based cohort studies on the association of serum 25-hydroxyvitamin D (25(OH)D) and all-cause mortality.

METHODS

Relevant studies were identified by systematically searching Medline, EMBASE and ISI Web of Knowledge. Reported hazard ratios (HRs) for 25(OH)D categories were recalculated employing comprehensive trend estimation from summarized dose-response data and pooled in a random effects model meta-analysis.

RESULTS

Overall, 12 original studies were included in the review and meta-analysis comprising 32,142 mainly elderly study participants with measured 25(OH)D of whom 6921 died during follow-up. An inverse association between 25(OH)D levels and all-cause mortality was found in all but two studies that was statistically significant in several of the individual studies. In meta-analysis, 25(OH)D levels were significantly inversely associated with all-cause mortality with a pooled HR of 0.92 (95% confidence interval: 0.89-0.95) for a 20 nmol/l increase in 25(OH)D levels.

CONCLUSION

In this meta-analysis of prospective, population-based cohort studies, a 20 nmol/l increase in 25(OH)D levels was associated with an 8% lower mortality in the general elderly population. This agrees with results from meta-analyses on randomized controlled trials that found a decrease in mortality with vitamin D3 supplementation of a comparable magnitude.

Determinants of vitamin D status in long-term renal transplant patients

In this study, we explored the determinants of vitamin D status in a large cohort of stable, Long-term renal transplant (RTx) patients. Serum 25(OH)D concentrations, and bone biochemistry parameters, were retrospectively analyzed from 266 RTx patients (>10 yr post-engraftment) presenting to clinic over the course of a year. Forty-five percent of the cohort were vitamin D deficient (<37.5 nM), 38% insufficient (37.5 75-nM), and 17% sufficient (>75 nM). Serum 25(OH)D concentrations were higher in patients presenting in summer (p<0.001) and in more active patients (p<0.05). RTx patients with non-melanoma skin cancer (NMSC) (n=45) had higher 25(OH)D concentrations than patients without NMSC (n=221; p<0.05) despite these patients being older, having worse eGFR, transplanted for longer, and less active physically (p<0.05). Lower 25(OH)D concentrations were associated with higher PTH concentrations (p<0.05) which, in the setting of widespread hypovitaminosis, suggests that secondary hyperparathyroidism was common in this cohort. In conclusion, season and activity status are important determinants of vitamin D status. We report, for the first time, that NMSC is associated with higher 25(OH)D, probably through increased UV radiation exposure. Long-term RTx patients may benefit from oral vitamin D supplementation, but this requires a randomized controlled trial to confirm.

New vitamin D analogs as potential therapeutics in melanoma

Extensive evidence shows that the active form of vitamin D3--1α,25-dihydroxyvitamin D3--plays an important role in cancer prevention, has tumorostatic activity and may potentially be used in therapy for melanoma. Vitamin D3 and its analogs (secosteroids) exert multiple effects on cancer cells, including inhibition of cell growth and induction of differentiation. Activity of secosteroids depends on multiple cellular factors, including expression of the vitamin D receptor. Despite its endogenous origin, the key drawback for the use of pharmacologically effective doses of 1α,25-dihydroxyvitamin D3 is its hypercalcemic effect leading to profound toxicity. The solution may lie in properties of vitamin D3 analogs with modified side chains, which demonstrate low calcemic activity but conserve the anti-tumor properties. Noncalcemic vitamin D compounds were found to be potent in multiple studies that mandate further clinical testing. Finally, recent studies revealed alternative metabolic pathways for secosteroids and new targets in the cells, which opens up new therapeutic possibilities.

Role of vitamin D metabolism in cutaneous tumour formation and progression

OBJECTIVES

Very limited information is available on the role of vitamin D in skin carcinogenesis. For most individuals, skin cancer can be readily managed with surgery; however, some patients may face life-threatening neoplasia. Sun exposure, specifically UV radiation, is a causative agent for development of skin cancer, though, somewhat ironically, sunlight through the production of vitamin D may have protective effect against some skin cancers. This review focuses on the development and progression of cutaneous carcinogenesis and the role of vitamin D in the prevention of the initiation and progression of lethal skin cancers.

KEY FINDINGS

Vitamin D is involved in regulation of multiple signalling pathways that have implications in carcinogenesis. Skin cancer metastasis depends on the tumour microenvironment, where vitamin D metabolites play a key role in prevention of certain molecular events involved in tumour progression. The vitamin D receptor (VDR) is a well-known potent regulator of cellular growth and differentiation.

SUMMARY

The VDR's possible involvement in cell death, tumour microenvironment and angiogenesis makes it a candidate agent for cancer regulation.

Associations of Sun Exposure with 25-Hydroxyvitamin D and Parathyroid Hormone Levels in a Cohort of Hypertensive Patients: The Graz Endocrine Causes of Hypertension (GECOH) Study

Sunlight-induced vitamin D, synthesis in the skin is the major source of vitamin D, but data on the relationship of sun-related behaviour with vitamin D and parathyroid hormone (PTH) levels are relatively sparse. We evaluated whether habitual sun exposure is associated with 25-hydroxyvitamin D (25[OH]D) and PTH levels and whether there exist seasonal variations. We examined 111 hypertensive patients in Austria (latitude 47° N). Frequent sunbathing at home and outdoor sports were associated with higher 25(OH)D levels (P < 0.05 for both). Red or blond scalp hair as a child, memory of sunburns, preferring sunbathing, frequent stays on the beach or in open-air pools, and solarium use were associated with lower PTH levels (P < 0.05 for all). Multiple linear regression analyses including age, sex, and body mass index showed that sun exposure score was significantly associated with 25(OH)D (beta coefficient = 0.27; P = 0.004) and by trend with PTH (beta coefficient = -0.16; P = 0.09). These associations were more prominent in summer in which 25(OH)D levels were significantly higher compared to winter. Translation of these findings into recommendations for the prevention and treatment of vitamin D deficiency remains a challenge for the future.

Vitamin D, cardiovascular disease and mortality

A poor vitamin D status, i.e. low serum levels of 25-hydroxyvitamin D [25(OH)D], is common in the general population. This finding is of concern not only because of the classic vitamin D effects on musculoskeletal outcomes, but also because expression of the vitamin D receptor (VDR) and vitamin D metabolizing enzymes in the heart and blood vessels suggests a role of vitamin D in the cardiovascular system. VDR-knockout mice suffer from cardiovascular disease (CVD), and various experimental studies suggest cardiovascular protection by vitamin D, including antiatherosclerotic, anti-inflammatory and direct cardio-protective actions, beneficial effects on classic cardiovascular risk factors as well as suppression of parathyroid hormone (PTH) levels. In epidemiological studies, low levels of 25(OH)D are associated with increased risk of CVD and mortality. Data from randomized controlled trials (RCTs) are sparse and have partially, but not consistently, shown some beneficial effects of vitamin D supplementation on cardiovascular risk factors (e.g. arterial hypertension). We have insufficient data on vitamin D effects on cardiovascular events, but meta-analyses of RCTs indicate that vitamin D may modestly reduce all-cause mortality. Despite accumulating data suggesting that a sufficient vitamin D status may protect against CVD, we still must wait for results of large-scale RCTs before raising general recommendations for vitamin D in the prevention and treatment of CVD. In current clinical practice, the overall risks and costs of vitamin D supplementation should be weighed against the potential adverse consequences of untreated vitamin D deficiency.

Vitamin D, sun, sunbeds and health

Objective

To review the health effects of solar radiation, sunbeds and vitamin D.

Design

The literature was searched in the electronic database MEDLINE to indentify published data between 1981 and 2011. Studies were included if they reported relative risk for cutaneous malignant melanoma (CMM) associated with sunbed use, vitamin D and UV effects on human health.

Setting

Data from different time periods for populations at different latitudes.

Subjects

Persons of different ages and ethnic groups.

Results

UV from sun and sunbeds is the main vitamin D source. Young people with white or pigmented skin in northern Europe have a low vitamin D status. A number of health benefits from sufficient levels of vitamin D have been identified. However, UV exposure has been suspected of causing skin cancer, notably CMM, and authorities warn against it.

Conclusions

The overall health benefit of an improved vitamin D status may be more important than the possibly increased CMM risk resulting from carefully increasing UV exposure. Important scientific facts behind this judgement are given.

A prospective, population-based study of 40,000 women regarding host factors, UV exposure and sunbed use in relation to risk and anatomic site of cutaneous melanoma

Prospective cohort studies about cutaneous melanoma (CM) risk are still few. Host factor- and UVR exposure data were collected prospectively by questionnaire in this population-based cohort study including 40,000 Swedish born women, aged 25-64 years at enrolment (1990). Risk for CM (Cox regression and Stepwise Cox regression [SCR], hazard ratios [HRs] with 95% Confidence Intervals [CI]) in relation to risk factors, age groups (older or younger than 40 years) and primary site, were analyzed. In 29,520 women with complete follow-up through 2007, 155 invasive and 60 in situ CM were recorded. High numbers of nevi (HR, 2.9; 95% CI, 1.7-5.0) and heredity (HR, 3.7; 95% CI, 2.0-6.8) were associated with risk for CM. SCR analysis added red hair as a risk factor. Sunbed use >10 times/year increased risk for women <40 years (HR, 2.5; 95% CI, 1.0-6.2) and a trend for risk associated with sunbathing vacations (HR, 1.4; 95% CI, 1.0-2.0) was shown for women >40 years. Trunk melanoma showed correlations with high numbers of nevi (HR, 3.0; 95% CI, 1.2-7.3) and heredity (HR, 3.2; 95% CI, 1.1-9.4). Head/neck site was correlated to sunbathing vacations (HR, 2.5; 95% CI, 1.2-5.3) and heredity (HR, 7.6; 95% CI, 1.8-31.8). Our study supports divergent etiologic pathways to CM, with high numbers of nevi correlated to increased risk for trunk CM. Furthermore, it confirms that high numbers of nevi, red hair and heredity for CM are the most important risk factors and frequent sunbed use might be a risk factor for younger women.

Malignant melanomas on head/neck and foot: differences in time and latitudinal trends in Norway

BACKGROUND

Cutaneous malignant melanoma (CMM) incidence continues to increase in many parts of the world. Solar ultraviolet (UV) radiation is the main environmental risk factor for CMM. Different body locations are subjected to different doses and exposure patterns of solar UV. Time and latitudinal trends of CMMs on shielded and exposed skin give valuable information about the aetiology of these cancers. In this study, we have compared the time and latitudinal trends of CMM incidence on skin areas which are chronically (head and neck) and rarely (foot) exposed to UV radiation, to gain more information about the relationship between sun doses, exposure patterns and melanomagenesis.

METHODS

We have analysed epidemiological data from the Cancer Registry of Norway, for foot and head and neck CMM for two time periods: 1966-1986 and 1987-2007.

RESULTS

Cutaneous malignant melanoma incidence rate on head and neck has increased with time, while incidence rates of foot CMM have remained almost constant with time in Norway. There is a large north-south gradient in incidence rates of CMM on head and neck in Norway, while there is almost no north-south gradient for CMM incidence on foot.

CONCLUSIONS

Comparisons of time trends and latitudinal trends of the incidence rates of CMM on head/neck and on foot indicate that solar radiation plays a role in the induction of the former CMM but probably not for the latter.

[Vitamin D and fractures in the elderly]

Osteoporosis and the subsequent fractures caused by this are a source of morbidity and mortality in the elderly population. It is also often the start of the cascade that culminates in frailty and dependence. Vitamin D has a direct relationship with the appearance of osteoporosis and with the risk of fractures. Receptors of this vitamin have also recently been described in other organs and systems of the body that are associated with muscle strength, cancer and overall mortality. Deficiency of this vitamin in the elderly population in Spain is very prevalent, both in the community and the hospitalised elderly. The diagnosis and treatment are straightforward and cheap. Its efficacy in the prevention of osteoporosis and in the appearance of fractures is perfectly demonstrated. In this review, we will look at the physiology and actions of this vitamin, as well as the principal studies that have demonstrated its effectiveness in the elderly population.

Widespread vitamin D insufficiency: A new challenge for primary prevention, with particular reference to multiple sclerosis

In the past 10 years, our knowledge of vitamin D has been revolutionized on two main points. Firstly, this vitamin is not only crucial for bone and calcium metabolism but also exerts major hormonal actions via its active metabolite (calcitriol) and specific receptors in almost all organs. The diverse non-classical actions of vitamin D-i.e. anti-inflammatory, immunomodulatory, antiproliferative and as a neurotransmitter-could have protective and preventive effects for a wide variety of pathologies, such as autoimmune diseases, cancer, infections and cardiovascular affections. Secondly, daily vitamin D requirements have been redefined thanks to many recent metabolic and pathological studies and are about 10 times higher than the amount considered sufficient until a few years ago. The fact that sunshine is the essential natural source of vitamin D and is limited in temperate and Nordic countries, coupled with the fact that modern lifestyle increasingly removes people from exposure to the sun, could explain why a great majority of the general population in these countries are in a state of vitamin D insufficiency. A lack of vitamin D can therefore also be observed in all pathologies but it may play a pathogenic role only in some of them. The incrimination of hypovitaminosis D as a risk factor is a reasonable assumption when several different research approaches used in a given pathology have consistently concluded that vitamin D is likely involved in that pathology. In multiple sclerosis, taken here as a prime example, there is a substantial rationale for vitamin D involvement, based on the findings of different experimental, epidemiological, genetic and immunological studies. Possible curative effects of vitamin D, in addition to a preventive action, are currently being tested but have not yet been demonstrated in most pathologies. However, these two questions appear to be clearly distinct and may involve notably different mechanisms. Lastly, since vitamin D insufficiency exists in most people living in mid- or high-latitude countries, vitamin D could exert multiple major preventive actions, simple supplementation is both safe and inexpensive and, for a vitamin-hormone, supplementation seems obligatory from a general preventive medical point of view alone, it follows that vitamin D supplementation should be organized in these countries to treat all those currently in a state of insufficiency, patients and 'normal' subjects alike, without further delay.

Melanoma incidence rates among whites in the U.S. Military

BACKGROUND

The U.S. Military and general populations may differ in the exposure to sunlight and other risk factors for melanoma and therefore the incidence rates of melanoma may be different in these two populations. However, few studies have compared melanoma incidence rates and trends over time between the military and the general population.

METHODS

Melanoma incidence rates from 1990 to 2004 among white active-duty military personnel and the general U.S. population were compared using data from the Department of Defense Automated Central Tumor Registry and the National Cancer Institute Surveillance, Epidemiology, and End Results program.

RESULTS

Age-adjusted melanoma rates overall were significantly lower in the military than in the general population; the incidence rate ratio was 0.75 for men and 0.56 for women. Age-specific rates, however, were significantly lower among individuals younger than 45 years, but significantly higher among those 45 years or older (P < 0.05). Melanoma incidence increased from 1990-1994 to 2000-2004 in both populations, with the most rapid increase (40%) among younger men in the military. Melanoma incidence rates also varied by branch of military service; rates were highest in the air force.

CONCLUSION

These results suggest that melanoma incidence rate patterns differ between the military and the general population.

IMPACT

Further studies of risk factors for melanoma in the military are needed to explain these findings.