Effect of the ultraviolet unweighted irradiance on the compliance of sunbeds in Spain

The use of tanning devices in Spain is regulated by the Royal Decree 1002/2002, which is based on the European standard EN60335-2-27. The European standard establishes that the total unweighted irradiance between 200 and 280 nm must not exceed 0.003 Wm-2, a requirement that the Spanish regulation modified to 0.03 Wm-2 from 250 to 295 nm. With these differences, the compliance consideration of an artificial tanning device can vary. Spectral irradiance measurements of 41 tanning devices performed with a high-resolution spectroradiometer were analyzed. None of the tanning devices had irradiances higher than 0.003 Wm-2 between 250 (the shortest wavelength measured by the spectroradiometer) and 280 nm, but the limit required by Spanish regulation was exceeded by 11 devices, of which one would have been considered compliant according to the European standard since the effective irradiance was lower than 0.3 Wm-2. Beyond noting the differences that can occur in sunbed inspections according to the established criteria, this work has shown the differences in the spectral and total values of devices in use in Spain, validating the need for periodic inspections.

Global Tanning Bed Advertising: A Comparison of Legal Regulations on Three Continents

Artificial ultraviolet radiation from tanning beds has been classified as carcinogenic by the International Agency for Research on Cancer in 2009. Several countries have subsequently introduced comprehensive legislation regulating commercial indoor tanning. Specific aspects of these regulations address tanning bed advertising and information requirements for tanning bed customers, which have been previously neglected in international comparisons of indoor tanning regulations. We performed a systematic search regarding legislation on these aspects in 131 legislative units across three continents (North America, Australia/New Zealand, Europe). The legal restrictions found varied widely in type and content. In 49 legislative units we identified total (n = 8) or partial legal bans (n = 41) on advertising for indoor tanning, while 64 legislative units enacted 5regulations that necessitate the dissemination of different types of specific health information to tanning bed customers. Nearly 40% of the legislative units of the study region lacked any legislation on these issues altogether. The heterogenous results emphasize the need for an international dialogue between health authorities and governments to harmonize the regulatory framework for tanning bed advertising and information requirements to a level better protecting the public from skin cancer. Our comprehensive international comparison can serve as a starting point for such a harmonization process that may ultimately protect the public worldwide from misleading tanning bed advertising.

Reasons for indoor tanning use and the acceptability of alternatives: A qualitative study

RATIONALE

Using indoor tanning devices is associated with substantial health consequences, such as an increased risk of melanoma and other skin cancers. Many people including minors and some at high risk of skin cancer continue to use these devices. In the absence of effective restrictions on use, it is important that behaviour change interventions are designed to reduce indoor tanning.

OBJECTIVE

To explore reasons for use of indoor tanning devices and the acceptability of alternatives in adult users residing in North-West England.

METHODS

Participants were required to be current indoor tanners aged 18 years and above and were recruited online. Twenty-one participants took part in either a focus group or semi-structured interview. An inductive thematic analysis was conducted.

RESULTS

Six themes were identified: psychological benefits; improving physical health; denial of health risks; alternatives do not meet psychological needs; alternatives do not meet physical needs; and perceived side-effects. Participants used indoor tanning devices to improve their self-esteem and to prevent sun damage to their skin (by gaining a 'base tan'). Participants appeared to justify their usage by responding defensively to avoid accepting they were at risk, exaggerating the benefits of indoor tanning, and discounting alternatives to indoor tanning. Alternatives to indoor tanning were perceived as risky for health, inadequate to provide the desired aesthetic, and incapable of meeting their self-esteem needs.

CONCLUSIONS

Interventions to reduce indoor tanning behaviour should increase sources of self-esteem other than appearance, increase media literacy and address defensive responses to information around indoor tanning and alternatives. Further research is needed to develop these interventions and assess their feasibility.

Association of Lifetime Indoor Tanning and Subsequent Risk of Cutaneous Squamous Cell Carcinoma

Importance

No study, to our knowledge, has prospectively investigated a dose-response association between lifetime indoor tanning and risk of cutaneous squamous cell carcinoma (SCC).

Objective

To investigate the dose-response association between lifetime indoor tanning and SCC risk, the association between duration of use and age at initiation with SCC risk, and the association between age at initiation and age at diagnosis.

Design, Setting, and Participants

This cohort study included data from women born from 1927 to 1963 from the Norwegian Women and Cancer study, established in 1991 with follow-up through December 31, 2015. Baseline questionnaires were issued to participants from 1991 to 2007, with follow-up questionnaires given every 5 to 7 years. Data analysis was performed from January 2, 2018, to March 2, 2019.

Exposures

Participants reported pigmentation factors. Sunburns, sunbathing vacations, and indoor tanning were reported for childhood, adolescence, and adulthood.

Main Outcomes and Measures

Information on all cancer diagnoses and dates of emigration or death were obtained through linkage to the Cancer Registry of Norway, using the unique personal identification number of Norwegian citizens.

Results

A total of 159 419 women (mean [SD] age at inclusion, 49.9 [8.3] years) were included in the study. During follow-up (mean [SD], 16.5 [6.4] years), 597 women were diagnosed with SCC. Risk of SCC increased with increasing cumulative number of indoor tanning sessions. The adjusted hazard ratio (HR) for highest use vs never use was 1.83 (95% CI, 1.38-2.42; P < .001 for trend). A significantly higher risk of SCC was found among women with 10 years or less of use (HR, 1.41; 95% CI, 1.08-1.85) and more than 10 years of use (HR, 1.43; 95% CI, 1.16-1.76) and among women with age at initiation of 30 years or older (HR, 1.36; 95% CI, 1.11-1.67) and younger than 30 years (HR, 1.51; 95% CI, 1.18-1.92) vs never users. No significant association was found between age at initiation and age at diagnosis (estimated regression coefficient, -0.09 [95% CI, -1.11 to 0.94] for age at initiation of ≥30 years and -0.02 [95% CI, -1.27 to 1.22] for <30 years vs never use).

Conclusion and Relevance

The findings provide supporting evidence that there is a dose-response association between indoor tanning and SCC risk among women. The association between cumulative exposure to indoor tanning and SCC risk was the same regardless of duration of use and age at initiation. These results support development of policies that regulate indoor tanning.

Evaluation for Skin Cancer and Precancer in Patients With Vitiligo Treated With Long-term Narrowband UV-B Phototherapy

Importance

Narrowband UV-B (NBUVB) phototherapy has been the mainstay in the treatment of vitiligo, but its long-term safety in terms of photocarcinogenesis has not been established.

Objectives

To investigate the risks of skin cancer and precancerous lesions among patients with vitiligo undergoing NBUVB phototherapy, based on the number of NBUVB phototherapy sessions.

Design, Setting, and Participants

This nationwide population-based retrospective cohort study enrolled 60 321 patients with vitiligo 20 years or older between January 1, 2007, and December 31, 2017. Patients and outcomes were identified through nationwide cohort data from the Korean national health insurance claims database, and frequency matching by age and sex was performed.

Exposures

The number of phototherapy sessions each patient received between 2008 and 2017. Patients were classified into 5 groups according to the number of phototherapy sessions (0 sessions, 20 105 patients; 1-49 sessions, 20 106 patients; 50-99 sessions, 9702 patients; 100-199 sessions, 6226 patients; and ≥200 sessions, 4182 patients). We also identifed patients who underwent at least 500 phototherapy sessions (717 patients).

Main Outcomes and Measures

Primary outcomes were the development of actinic keratosis, Bowen disease, nonmelanoma skin cancer, or melanoma after enrollment.

Results

Among the 60 321 patients with vitiligo in this study (33 617 women; mean [SD] age, 50.2 [14.9] years), the risks of Bowen disease (<50 sessions of phototherapy: hazard ratio [HR], 0.289 [95% CI, 0.060-1.392]; 50-99 sessions: HR, 0.603 [95% CI, 0.125-2.904]; 100-199 sessions: HR, 1.273 [95% CI, 0.329-4.924]; ≥200 sessions: HR, 1.021 [95% CI, 0.212-4.919]), nonmelanoma skin cancer (<50 sessions: HR, 0.914 [95% CI, 0.533-1.567]; 50-99 sessions: HR, 0.765 [95% CI, 0.372-1.576]; 100-199 sessions: HR, 0.960 [95% CI, 0.453-2.034]; ≥200 sessions: HR, 0.905 [95% CI, 0.395-2.073]), and melanoma (<50 sessions: HR, 0.660 [95% CI, 0.286-1.526]; 50-99 sessions: HR, 0.907 [95% CI, 0.348-2.362]; 100-199 sessions: HR, 0.648 [95% CI, 0.186-2.255]; ≥200 sessions: HR, 0.539 [95% CI, 0.122-2.374]) did not increase after phototherapy. The risk of actinic keratosis increased significantly for those who had undergone 200 or more NBUVB phototherapy sessions (HR, 2.269 [95% CI, 1.530-3.365]). A total of 717 patients with vitiligo underwent at least 500 sessions of NBUVB phototherapy; their risks of nonmelanoma skin cancer and melanoma were no greater than those of the patients who did not undergo NBUVB phototherapy (nonmelanoma skin cancer: HR, 0.563 [95% CI, 0.076-4.142]; melanoma: HR, not applicable).

Conclusions and Relevance

Our results suggest that long-term NBUVB phototherapy is not associated with an increased risk of skin cancer in patients with vitiligo and that NBUVB phototherapy may be considered a safe treatment.

UV Driven Tanning Salons: Danger on Main Street

Appearing in the early 1980s, at a time when UVA was considered as relatively safe, the tanning industry has substantially developed in occidental countries, especially in Northern European countries. In Europe, the erythemally-weighted irradiance of a modern sunbed should not exceed 0.3 W/m², equivalent to an UV index of 12, i.e. to a tropical midday sun, but increased in recent years, the UV spectrum emitted by sunbeds had evolved towards higher UVA irradiance and solariums UV had become even less similar to natural sun.

Review of interventions to reduce ultraviolet tanning: Need for treatments targeting excessive tanning, an emerging addictive behavior

Millions of Americans engage in tanning each year, defined as intentional ultraviolet radiation (UVR) exposure in the form of sunbathing or the use of indoor tanning beds. An emerging body of research suggests that UVR has addictive properties and some tanners engage in excessive tanning. This article provides an overview of the evidence of tanning addiction and a systematic review of existing tanning interventions with the goal of evaluating their potential to impact addicted tanners. Our search identified 24 intervention studies that were summarized and discussed according to 3 primary themes. First, there is a dearth of tanning interventions that target excessive tanning or are designed as treatments for tanning addiction. Second, tanning interventions are primarily educational interventions designed to increase knowledge of the risks of tanning. Third, there are notable aspects of existing tanning interventions that are relevant to addiction science, including the use of brief motivational and cognitive-behavioral-based interventions. Future directions are considered including recommendations for utilizing the existing evidence base to formulate interventions targeting excessive tanners. (PsycINFO Database Record

DYNAMIC RESPONSE OF CCD ARRAY SPECTRORADIOMETERS

A number of factors affect the measurements by charge coupled (CCD) array spectroradiometers, including stray light, dynamic response and ambient temperature. The departure from linearity was assessed for four CCD array spectroradiometers and linearity correction calculated with standard uncertainties error estimates. A fixed irradiance source supplemented with neutral density filters was used to allow tests to cover a full range of operational conditions. The dependence of the dynamic response on well depth and integration time was investigated. One spectroradiometer exhibited an accumulated departure from linearity of ∼20 % near the top of the well; for others the departure from linearity was less pronounced.

Sunbeds' ultraviolet radiation measurements with different radiometers and criteria for compliance assessment set by the national competent authority in Greece

In order to ground the credibility of the sunbeds' ultraviolet radiation compliance assessment with the 0.3W/m(2) erythema effective irradiance limit, it is highly important to use reliable measuring equipment and to justify reasonably the measurement's result. Recently, the first surveillance action of the artificial tanning sector in Greece has been finalised. The action consisted of in situ erythema effective irradiance measurements from sunbeds at commercial premises offering artificial tanning services at various cities throughout Greece. Four different broadband erythemal weighted radiometers were used in order to compare them during in situ sunbeds' radiation measurements, at commercial premises, and to choose the most suitable one for compliance inspections. Furthermore a rationale has been introduced in order to compare the measurement's result with the limit, and decide about compliance or not, taking into account the measurement's expanded uncertainty. According to this approach, compliance, probable compliance or non-compliance is verified when the measurement's result taking into account the measurement's expanded uncertainty does not, probably or does exceed the 0.3W/m(2) limit, respectively. Ultraviolet radiation exceeded the 0.3W/m(2) erythema effective irradiance limit in 63.5% (33 out of 52) of the sunbeds and probably exceeded the limit in 11.5% (6 out of 52) of the sunbeds, according to the measurements performed with the radiometer which was chosen as the most suitable one and the proposed rationale for compliance justification.

The Growing Burden of Invasive Melanoma: Projections of Incidence Rates and Numbers of New Cases in Six Susceptible Populations through 2031

New melanoma therapies are being developed rapidly, complementing prevention and detection strategies for disease control. Estimating the future burden of melanoma is necessary for deciding how best to deploy limited resources to achieve effective melanoma control. Using three decades of cancer registry data (1982-2011) from six populations with moderate to high melanoma incidence (US whites and the populations of the United Kingdom, Sweden, Norway, Australia, New Zealand), we applied age-period-cohort models to describe current trends and project future incidence rates and numbers of melanomas out to 2031. Between 1982 and 2011, melanoma rates in US whites, and the populations of the United Kingdom, Sweden, and Norway increased at more than 3% annually and are projected to continue rising until at least 2022. Melanoma incidence in Australia has been declining since 2005 (-0.7% per year), and melanoma incidence in New Zealand is increasing but is projected to decline soon. The numbers of new melanoma cases will rise in all six populations because of aging populations and high age-specific rates in the elderly. In US whites, annual new cases will rise from around 70,000 in 2007-2011 to 116,000 in 2026-2031, with 79% of the increase attributable to rising age-specific rates and 21% to population growth and aging. The continued increases in case numbers in all six populations through 2031 will increase the challenges of melanoma control.

Ultraviolet exposure from indoor tanning devices: a systematic review

Use of indoor tanning devices increases the risk of cutaneous melanoma and nonmelanoma skin cancer. Indoor tanning devices have become important sources of ultraviolet (UV) exposure, both UVB and UVA. This systematic review assessed UV measurements performed in indoor tanning devices related to irradiance level, wavelength distribution and similarities to natural sun. The study was performed in accordance with the MOOSE and PRISMA guidelines. We searched PubMed, Embase and Web of Science from inception to May 2015, and also examined the reference lists of the retrieved studies. Eighteen studies were included. Twelve studies examined the erythema-weighted UV irradiances of indoor tanning devices, 11 studies examined UVB and 13 studies studied UVA. Compliance with irradiance limits was reported in nine studies. Erythema-weighted irradiances were highest in the most recent studies. Most studies had mean values higher than from natural sun and with large variations between devices. All studies except two had mean unweighted UVB irradiances lower than from natural summer sun (at latitudes from 37°S to 35°N), while mean unweighted UVA irradiances were, with one exception, substantially higher than from natural sun. The high values of UVA exposure from modern tanning devices are alarming in light of the increased focus on UVA irradiance as a carcinogen, and as UVA exposure confers little protection against subsequent UV exposure.

Melanoma Epidemiology and Prevention

The epidemiology of melanoma is complex, and individual risk depends on sun exposure, host factors, and genetic factors, and in their interactions as well. Sun exposure can be classified as intermittent, chronic, or cumulative (overall) exposure, and each appears to have a different effect on type of melanoma. Other environmental factors, such as chemical exposures-either through occupation, atmosphere, or food-may increase risk for melanoma, and this area warrants further study. Host factors that are well known to be important are the numbers and types of nevi and the skin phenotype. Genetic factors are classified as high-penetrant genes, moderate-risk genes, or low-risk genetic polymorphisms. Subtypes of tumors, such as BRAF-mutated tumors, have different risk factors as well as different therapies. Prevention of melanoma has been attempted using various strategies in specific subpopulations, but to date optimal interventions to reduce incidence have not emerged.

Effective ultraviolet irradiance measurements from artificial tanning devices in Greece

Artificial tanning remains very popular worldwide, despite the International Agency for Research on Cancer classification of ultraviolet (UV) radiation from sunbeds as 'carcinogenic to humans'. Greek Atomic Energy Commission has initiated a surveillance action of the artificial tanning devices in Greece in order to record the effective irradiance levels from the sunbeds and to inform and synchronise the domestic artificial tanning business sector with the requirements of the European Standard EN 60335-2-27:2010. In this direction, in situ measurements of UV emissions from sunbeds in solaria businesses all over Greece were performed from October 2013 until July 2014, with a radiometer and a portable single-monochromator spectrophotometer. Analysis of the measurements' results revealed that effective irradiance in ∼60 % of the measured sunbeds exceeded the 0.3 W m(-2) limit value set by EN 60335-2-27:2010 and only 20 % of the devices could be categorised as UV type 3.

A review of the use of tanning beds as a dermatological treatment

Introduction

In-office phototherapy is an effective treatment for many dermatologic conditions, however, many patients are unable to adhere to the rigorous travel and time commitments sometimes needed. Tanning bed facilities are nearly ubiquitous in modern society and could represent a more convenient means to obtain ultraviolet (UV) exposure when office phototherapy is not feasible. The purpose of this study was to review available evidence on the use of tanning facilities as a treatment for dermatologic conditions.

Methods

PubMed was searched on February 2015 for “tanning beds” and “phototherapy”, and with some dermatologic conditions sensitive to UV light, including “psoriasis”, “mycosis fungoides”, “acne”, “atopic dermatitis” and “eczema”. From there, further articles were found using the reference sections of the initial papers. A similar methodology was used with the Google Scholar search engine. Only articles in English and prospective studies were included in this review.

Results

We found studies validating the use of tanning facilities for psoriasis treatment. Use as a treatment option for atopic dermatitis, mycosis fungoides, acne, scleroderma, vitiligo, and pruritus, as well as other UV sensitive dermatoses, may also be beneficial. This study is limited by the lack of double-blind, placebo-controlled trials, long-term follow-up studies, and meta-analyses for tanning facility use in dermatologic phototherapy, and by the lack of standardization of both tanning facilities and exposure dosing.

Conclusion

Unsupervised sun exposure is a standard recommendation for some patients to obtain phototherapy. Selected use of commercial tanning beds in the treatment of dermatologic conditions may be another useful and effective treatment for those patients with an inability to access office-based or home-based phototherapy.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-015-0071-8) contains supplementary material, which is available to authorized users.

Modulating the structure of EGFR with UV light: new possibilities in cancer therapy

The epidermal growth factor receptor (EGFR) is a member of the ErbB family of receptor tyrosine kinases. EGFR is activated upon binding to e.g. epidermal growth factor (EGF), leading to cell survival, proliferation and migration. EGFR overactivation is associated with tumor progression. We have previously shown that low dose UVB illumination of cancer cells overexpressing EGFR prior to adding EGF halted the EGFR signaling pathway. We here show that UVB illumination of the extracellular domain of EGFR (sEGFR) induces protein conformational changes, disulphide bridge breakage and formation of tryptophan and tyrosine photoproducts such as dityrosine, N-formylkynurenine and kynurenine. Fluorescence spectroscopy, circular dichroism and thermal studies confirm the occurrence of conformational changes. An immunoassay has confirmed that UVB light induces structural changes in the EGF binding site. A monoclonal antibody which competes with EGF for binding sEGFR was used. We report clear evidence that UVB light induces structural changes in EGFR that impairs the correct binding of an EGFR specific antibody that competes with EGF for binding EGFR, confirming that the 3D structure of the EGFR binding domain suffered conformational changes upon UV illumination. The irradiance used is in the same order of magnitude as the integrated intensity in the solar UVB range. The new photonic technology disables a key receptor and is most likely applicable to the treatment of various types of cancer, alone or in combination with other therapies.

Effects of ambient temperature on the performance of CCD array spectroradiometers and practical implications for field measurements

The performance of miniature CCD array spectroradiometers, which are widely used for the assessment of personal and environmental exposures, may be affected by variations in ambient temperature. The dark signal, spectral sensitivity and wavelength position of six different array spectroradiometer models, produced by two different manufacturers, were assessed in ambient temperatures ranging from 5 °C to 40 °C. The results are presented with a discussion of the practical implications for field measurements when the instruments are used outside of a temperature controlled environment.

Exposure to indoor tanning without burning and melanoma risk by sunburn history

Indoor tanning is carcinogenic to humans. Individuals report that they tan indoors before planning to be in the sun to prevent sunburns, but whether skin cancer is subsequently reduced is unknown. Using a population-based case-control study, we calculated the association between melanoma and indoor tanning after excluding exposed participants reporting indoor tanning-related burns, stratified by their number of lifetime sunburns (0, 1-2, 3-5, >5). Confounding was addressed using propensity score analysis methods. All statistical tests were two-sided. We observed increased risk of melanoma across all sunburn categories for participants who had tanned indoors without burning compared with those who never tanned indoors, including those who reported zero lifetime sunburns (odds ratio = 3.87; 95% confidence interval = 1.68 to 8.91; P = .002). These data provide evidence that indoor tanning is a risk factor for melanoma even among persons who reported never experiencing burns from indoor tanning or outdoor sun exposure.

Exposure to indoor tanning without burning and melanoma risk by sunburn history

Indoor tanning is carcinogenic to humans. Individuals report that they tan indoors before planning to be in the sun to prevent sunburns, but whether skin cancer is subsequently reduced is unknown. Using a population-based case-control study, we calculated the association between melanoma and indoor tanning after excluding exposed participants reporting indoor tanning-related burns, stratified by their number of lifetime sunburns (0, 1-2, 3-5, >5). Confounding was addressed using propensity score analysis methods. All statistical tests were two-sided. We observed increased risk of melanoma across all sunburn categories for participants who had tanned indoors without burning compared with those who never tanned indoors, including those who reported zero lifetime sunburns (odds ratio = 3.87; 95% confidence interval = 1.68 to 8.91; P = .002). These data provide evidence that indoor tanning is a risk factor for melanoma even among persons who reported never experiencing burns from indoor tanning or outdoor sun exposure.

Melanocytes are selectively vulnerable to UVA-mediated bystander oxidative signaling

Long-wave UVA is the major component of terrestrial UV radiation and is also the predominant constituent of indoor sunlamps, both of which have been shown to increase cutaneous melanoma risk. Using a two-chamber model, we show that UVA-exposed target cells induce intercellular oxidative signaling to non-irradiated bystander cells. This UVA-mediated bystander stress is observed between all three cutaneous cell types (i.e., keratinocytes, melanocytes, and fibroblasts). Significantly, melanocytes appear to be more resistant to direct UVA effects compared with keratinocytes and fibroblasts, although melanocytes are also more susceptible to bystander oxidative signaling. The extensive intercellular flux of oxidative species has not been previously appreciated and could possibly contribute to the observed cancer risk associated with prolonged UVA exposure.

Sunbed use and cutaneous melanoma in Norway

Aims: Incidence rates of cutaneous melanoma (CM) in light skinned people in Norway are among the highest in the world. Sunbed use has increased in Norway since 1980. We will try to elucidate whether there is any correlation between the increase in sunbed use and the CM incidence rates, whether the increase in CM risk is similar for all age groups, and whether the possible difference between young and old persons can inform future healthcare strategies. Methods: The frequency of sunbed use by different age groups in the time period 1980–2011 and incidence rates (1980–2009) of CM at different age groups in Norway were studied. Time in minutes per day spent in front of screen of computers or TVs for boys and girls was also analysed. Results: The number of sunbed sessions per year in Norway increased throughout the entire period. The number of men and women diagnosed with CM per year, all ages combined, also increased. Sunbed use increased at a similar rate for three age groups (0–19, 20–50, and >50 years old), while the age-adjusted CM incidence rate increased only for the oldest group. Time spent in front of the screen of computers or TVs increased from 1985 to 2005 and is still increasing. Conclusions: CM incidence is decreasing while sunbed use is increasing in younger age groups. The present data indicate that more work needs to be done before one can know whether the overall health effects of sunbed exposure are positive or negative.

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.

DNA repair variants, indoor tanning, and risk of melanoma

Although ultraviolet radiation (UV) exposure from indoor tanning has been linked to an increased risk of melanoma, the role of DNA repair genes in this process is unknown. We evaluated the association of 92 single nucleotide polymorphisms (SNPs) in 20 DNA repair genes with the risk of melanoma and indoor tanning among 929 patients with melanoma and 817 controls from the Minnesota Skin Health Study. Significant associations with melanoma risk were identified for SNPs in ERCC4, ERCC6, RFC1, XPC, MGMT, and FBRSL1 genes; with a cutoff of P < 0.05. ERCC6 and FBRSL1 gene variants and haplotypes interacted with indoor tanning. However, none of the 92 SNPs tested met the correction criteria for multiple comparisons. This study, based on an a priori interest in investigating the role of DNA repair capacity using variants in base excision and nucleotide excision repair, identified several genes that may play a role in resolving UV-induced DNA damage.

Photodegradation of cobalamins in aqueous solutions and in human blood

Vitamin B12 (cobalamin) is required for proper red blood cell formation, neurologic function, and DNA synthesis. Cobalamins in solutions are light sensitive, but no comprehensive study has been performed to compare the photostability of different cobalamins under UVA exposure. Their indirect photodegradation due to their antioxidant properties and their photostability in vivo have also not been studied so far. The photodegradation of four cobalamins (methylcobalamin (MeCbl), adenosylcobalamin (AdCbl), hydroxocobalamin (OHCbl) and cyanocobalamin (CNCbl)) under UVA exposure in aqueous solutions (pH=7.4) have been investigated by absorption spectroscopy. The photodegradation of OHCbl in the absence and presence of the endogenous photosensitizer riboflavin was studied. Serum vitamin B12 concentrations before and after summer were measured in four patients with psoriasis. All studied cobalamins are photolabile. The biologically active forms of cobalamin, AdCbl and MeCbl, are converted to OHCbl within seconds during UVA exposure. OHCbl is the most stable cobalamin. However, reactive oxygen species increases the degradation rate of OHCbl. Our pilot study on humans demonstrates that serum vitamin B12 concentrations are not significantly affected during summertime in Norway. Further work is needed to determine vitamin B12 photostability in humans living at lower latitudes or using sunbeds.

Nine out of 10 sunbeds in England emit ultraviolet radiation levels that exceed current safety limits

BACKGROUND

Exposure to ultraviolet (UV) radiation from sunlight is recognized as the principal cause of skin cancer. Moreover, sunbeds have been classified as carcinogenic by the International Agency for Research on Cancer. Despite this, there is a shortage of objective data on UV exposure levels in sunbeds in England.

OBJECTIVES

We set out to measure UV emission levels in sunbeds at sites around England, and to compare these levels with both current standards and natural sunlight.

METHODS

Between October 2010 and February 2011, UV spectra were measured on site from a total of 402 artificial tanning units in England. Measurement instrumentation was calibrated, traceable to the National Physical Laboratory. Compliance with the relevant British and European standard was determined, and a skin-cancer weighting factor was used to compare the carcinogenic potential of sunbeds with that of sunlight.

RESULTS

For compliance with the European standard, erythemal-effective irradiance should not exceed 0·3 W m(-2). The values that we measured ranged between 0·10 and 1·32 W m(-2) with a mean of 0·56 ± 0·21 W m(-2) . Only 10% of sunbeds surveyed were within the recommended limit. Application of the skin-cancer weighting factor produced values that varied from 0·17 to 2·52 W m(-2) with a mean of 0·99 ± 0·41 W m(-2). The comparable value for Mediterranean noon day sun was 0·43 W m .

CONCLUSIONS

Nine out of 10 sunbeds surveyed throughout England emitted levels of UV radiation that exceed the maximum levels contained within the European standard. Moreover, the skin cancer risk for comparable times of exposure was up to six times higher than that for Mediterranean sunlight. This situation is unacceptable and stricter control measures must be put in place.

Does melanoma begin in a melanocyte stem cell?

What is the cellular origin of melanoma? What role do melanocyte stem cells (MSC) and other melanocyte precursors play in the development of melanoma? Are MSCs and other latent melanocyte precursors more susceptible to solar radiation? These and many other questions can be very effectively addressed using the zebrafish model. Zebrafish have a robust regenerative capability, permitting the study of how MSCs are regulated and recruited at specific times and places to generate the pigment pattern following fin amputation or melanocyte ablation. They can be used to determine the effects of environmental radiation on the proliferation, survival, repair, and differentiation of MSCs. Our lab is using zebrafish to investigate how UVA- (320-400 nm) and UVB- (290-320 nm) induced damage to MSCs may contribute to the development of melanoma. A review is given of MSCs in zebrafish as well as experimental techniques and drugs for manipulating MSC populations. These techniques can be used to design experiments to help answer many questions regarding the role of MSCs or melanocyte precursors in the formation of melanoma stem cells and tumors following exposure to UVA/UVB radiation.

Beneficial effects of UV radiation other than via vitamin D production

Most of the positive effects of solar radiation are mediated via ultraviolet-B (UVB) induced production of vitamin D in skin. However, several other pathways may exist for the action of ultraviolet (UV) radiation on humans as focused on in this review. One is induction of cosmetic tanning (immediate pigment darkening, persistent pigment darkening and delayed tanning). UVB-induced, delayed tanning (increases melanin in skin after several days), acts as a sunscreen. Several human skin diseases, like psoriasis, vitiligo, atopic dermatitis and localized scleroderma, can be treated with solar radiation (heliotherapy) or artificial UV radiation (phototherapy). UV exposure can suppress the clinical symptoms of multiple sclerosis independently of vitamin D synthesis. Furthermore, UV generates nitric oxide (NO), which may reduce blood pressure and generally improve cardiovascular health. UVA-induced NO may also have antimicrobial effects and furthermore, act as a neurotransmitter. Finally, UV exposure may improve mood through the release of endorphins.

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.