Sun protection and Vitamin D: three dimensions of obfuscation

Cholecalciferol or Calcifediol in the Management of Vitamin D Deficiency

Vitamin D deficiency is a global health problem due to its high prevalence and its negative consequences on musculoskeletal and extra-skeletal health. In our comparative review of the two exogenous vitamin D supplementation options most used in our care setting, we found that cholecalciferol has more scientific evidence with positive results than calcifediol in musculoskeletal diseases and that it is the form of vitamin D of choice in the most accepted and internationally recognized clinical guidelines on the management of osteoporosis. Cholecalciferol, unlike calcifediol, guarantees an exact dosage in IU (International Units) of vitamin D and has pharmacokinetic properties that allow either daily or even weekly, fortnightly, or monthly administration in its equivalent doses, which can facilitate adherence to treatment. Regardless of the pattern of administration, cholecalciferol may be more likely to achieve serum levels of 25(OH)D (25-hydroxy-vitamin D) of 30-50 ng/mL, an interval considered optimal for maximum benefit at the lowest risk. In summary, the form of vitamin D of choice for exogenous supplementation should be cholecalciferol, with calcifediol reserved for patients with liver failure or severe intestinal malabsorption syndromes.

Will every child have allergic rhinitis soon?

OBJECTIVES

Given the increasing prevalence of AR amongst children, we aimed to review the literature regarding the future of AR in this population.

METHODS

We searched the PubMed, Google and Proquest Central databases at Kırıkkale University Library. Search terms used were: "allergic rhinitis", "children", "paediatric", "allergy", "future", "risk factors", "treatment", "pharmacotherapy" and/or "allergen - specific immunotherapy". With regard to risk factors for allergic rhinitis, the terms "Environmental factors", "Improved hygiene", "Increased indoor allergen exposure", "Farms, villages, worms, and other parasites", "Environmental toxicants", "Diet", "Lifestyle changes", "Air pollution" and "Climate factors" were searched for. "Prevention of allergic diseases" and "Allergen-specific immunotherapy in the future" were also included in the search.

RESULTS

AR has a high prevalence and causes considerable morbidity, has associated comorbidity and features specific complications. The principal treatments rely on avoiding the allergens responsible, and administering drug treatment or immunotherapy, which targets specific antigens. Genetic drift does not explain the rising prevalence of allergic disorders, but multifactorial environmental factors are likely culprits. Amongst such environmental factors to consider are the rise in caesarean births, decreases in breast feeding, dietary changes resulting in less fresh produce being consumed, the eradication of intestinal worm infestations, alterations in the way homes are aired and heated, children taking less exercise and being outdoors for shorter periods, whilst also having more contact with pollution.

CONCLUSION

Barring substantial lifestyle alterations, more and more children are likely to develop AR. It may prove feasible to stop allergy developing in the first place through manipulation of the microbiome, but the exact format such a modification should involve remains to be discovered. Molecular allergological techniques do offer the prospect of more precisely targeted immunotherapy, the sole disease modifier at present. However, at present the complexity and cost of such interventions prevents their widespread use and research in this area is still needed. The majority of children with AR are going to be managed using nasal saline sprays, since they are the most straightforward and least risky alternative for first line treatment.

Is calcifediol better than cholecalciferol for vitamin D supplementation?

Modest and even severe vitamin D deficiency is widely prevalent around the world. There is consensus that a good vitamin D status is necessary for bone and general health. Similarly, a better vitamin D status is essential for optimal efficacy of antiresorptive treatments. Supplementation of food with vitamin D or using vitamin D supplements is the most widely used strategy to improve the vitamin status. Cholecalciferol (vitamin D₃) and ergocalciferol (vitamin D₂) are the most widely used compounds and the relative use of both products depends on historical or practical reasons. Oral intake of calcifediol (25OHD₃) rather than vitamin D itself should also be considered for oral supplementation. We reviewed all publications dealing with a comparison of oral cholecalciferol with oral calcifediol as to define the relative efficacy of both compounds for improving the vitamin D status. First, oral calcifediol results in a more rapid increase in serum 25OHD compared to oral cholecalciferol. Second, oral calcifediol is more potent than cholecalciferol, so that lower dosages are needed. Based on the results of nine RCTs comparing physiologic doses of oral cholecalciferol with oral calcifediol, calcifediol was 3.2-fold more potent than oral cholecalciferol. Indeed, when using dosages ≤ 25 μg/day, serum 25OHD increased by 1.5 ± 0.9 nmol/l for each 1 μg cholecalciferol, whereas this was 4.8 ± 1.2 nmol/l for oral calcifediol_. Third, oral calcifediol has a higher rate of intestinal absorption and this may have important advantages in case of decreased intestinal absorption capacity due to a variety of diseases. A potential additional advantage of oral calcifediol is a linear dose-response curve, irrespective of baseline serum 25OHD, whereas the rise in serum 25OHD is lower after oral cholecalciferol, when baseline serum 25OHD is higher. Finally, intermittent intake of calcifediol results in fairly stable serum 25OHD compared with greater fluctuations after intermittent oral cholecalciferol.

Vitamin D in cutaneous carcinogenesis: part I

Skin cancer is the most common cancer in the United States. Exposure to ultraviolet radiation is a known risk factor for skin cancer but is also the principal means by which the body obtains vitamin D. Several studies have suggested that vitamin D plays a protective role in a variety of internal malignancies. With regard to skin cancer, epidemiologic and laboratory studies suggest that vitamin D and its metabolites may have a similar protective effect. These noncalcemic actions of vitamin D have called into question whether the current recommended intake of vitamin D is too low for optimal health and cancer prevention. Part I will review the role of vitamin D in the epidermis; part II will review the role of vitamin D in keratinocyte-derived tumors to help frame the discussion on the possible role of vitamin D in the prevention of skin cancer.

[Skin, sun exposure and vitamin D: facts and controversies]

Vitamin D plays a clearly defined role in phosphorus, calcium and bone metabolism. In addition to its effects on cellular proliferation and differentiation, and on immunity, it appears to exert other action, poorly understood to date, on human physiology and disease. A number of epidemiological studies have demonstrated a protective role of sun exposure with regard to the incidence of certain immune diseases and cancer, and upon the related mortality rates. Furthermore, over the last 10 years, studies have purported to find levels judged "inadequate" in numerous populations, and, in the absence of any strict scientific arguments, a correlation was established by certain authors between supposedly "inadequate" levels, sun exposure and risk of cancer. However, analysis of the literature shows that there is in fact no precise and consensual definition of normal ranges and that the notion of inadequacy was created artificially using assay techniques lacking in sensitivity and reproducibility. Photosynthesis of vitamin D can in fact be considered perfectly adequate in the majority of populations. However, greater care is needed with elderly subjects and with subjects exposed very little to sunlight. Current studies show that the means of photoprotection used in everyday life do not adversely affect such photosynthesis. In the event of documented vitamin D deficiency, oral supplements should be given, and exposure to natural or artificial UV radiation should not be prescribed. Ultraviolet radiation has been shown to be carcinogenic and responsible for the onset of most skin cancers, and the population must be warned against misleading advertising from the tanning industry. Care should also be taken with regard to the potential harmful effects of inappropriate vitamin D supplementation.

Time to get serious about skin cancer prevention

In this commentary, we discuss the skin cancer epidemic in the United States and provide data to indicate that the United States public is not protecting itself from ultraviolet radiation, the primary risk factor for melanoma, and nonmelanoma skin cancer. In our opinion, skin cancer control in this country may be hindered by uncertainty about the effectiveness of sun protection strategies, inconsistent messages about the relative effectiveness of sun protection measures by federal and national organizations, and conventional research approaches that have identified few effective sun protection interventions for adults and targeted individuals for behavior change without considering the environmental context. A policy and research agenda is put forth to remedy the apparent insufficiencies in the current approach to skin cancer prevention in the United States.

Validity and use of the UV index: report from the UVI working group, Schloss Hohenkammer, Germany, 5-7 December 2011

The adequacy of the UV Index (UVI), a simple measure of ambient solar ultraviolet (UV) radiation, has been questioned on the basis of recent scientific data on the importance of vitamin D for human health, the mutagenic capacity of radiation in the UVA wavelength, and limitations in the behavioral impact of the UVI as a public awareness tool. A working group convened by ICNIRP and WHO met to assess whether modifications of the UVI were warranted and to discuss ways of improving its effectiveness as a guide to healthy sun-protective behavior. A UV Index greater than 3 was confirmed as indicating ambient UV levels at which harmful sun exposure and sunburns could occur and hence as the threshold for promoting preventive messages. There is currently insufficient evidence about the quantitative relationship of sun exposure, vitamin D, and human health to include vitamin D considerations in sun protection recommendations. The role of UVA in sunlight-induced dermal immunosuppression and DNA damage was acknowledged, but the contribution of UVA to skin carcinogenesis could not be quantified precisely. As ambient UVA and UVB levels mostly vary in parallel in real life situations, any minor modification of the UVI weighting function with respect to UVA-induced skin cancer would not be expected to have a significant impact on the UV Index. Though it has been shown that the UV Index can raise awareness of the risk of UV radiation to some extent, the UVI does not appear to change attitudes to sun protection or behavior in the way it is presently used. Changes in the UVI itself were not warranted based on these findings, but rather research testing health behavior models, including the roles of self-efficacy and self-affirmation in relation to intention to use sun protection among different susceptible groups, should be carried out to develop more successful strategies toward improving sun protection behavior.

Compliance with sunscreen advice in a survey of adults engaged in outdoor winter recreation at high-elevation ski areas

BACKGROUND

Adults are advised to wear sunscreen with a sun protection factor (SPF) of 15 or higher, apply it up to 30 minutes before sun exposure, and reapply it after 2 hours to reduce exposure to ultraviolet radiation in sunlight for the prevention of skin cancer.

OBJECTIVE

This study investigated the extent to which adults comply with sunscreen advice.

METHODS

A survey was conducted with 4837 adult skiers and snowboarders at 28 high-altitude ski areas in western North America in January through April 2001 through 2002. Respondents self-reported use of sunscreen, its SPF, time of first application, and reapplication.

RESULTS

Only 4.4% (95% confidence interval [CI] = ±0.6) of adults were in full compliance with all sunscreen advice. Half (49.8% [95% CI = ±1.4]) complied with SPF 15 or higher advice. Of those wearing sunscreen, 73.2% (95% CI = ±1.8) applied the sunscreen 30 minutes before beginning skiing/snowboarding, but only 20.4% (95% CI = ±2.0) complied with advice to reapply it after 2 hours. Total compliance was lowest during inclement weather, on low-ultraviolet days, by men, and among respondents who believed skin cancer was unimportant and with low sun-sensitive skin. It was positively associated with wearing lip balm and hats with a brim.

LIMITATIONS

The sample was predominantly male and of high socioeconomic status; the results apply most to winter recreation when ultraviolet radiation levels are low, and sunscreen use was assessed by self-report.

CONCLUSION

Although the recommendation to use SPF 15 or higher sunscreen has reached many adults, the reapplication advice is heeded by few adults and needs to be highlighted in future sun safety promotions.

Why modest but widespread improvement of the vitamin D status is the best strategy?

Vitamin D is a precursor for a secosteroid ligand of a major transcription factor, VDR, and is vital for normal bone mineralization. It also regulates many other genes so that it may be involved in many extra skeletal health effects. The optimal vitamin D status is controversial but there is a wide unanimity that the vitamin D status can and should be improved for some risk groups. To normalize serum calcium homeostasis as based on normal levels of serum 1,25(OH)₂D₃ or parathyroid hormone, or to optimize intestinal calcium absorption or bone mineral density in adults or elderly subjects, serum 25OHD should be 20 ng/ml or higher. A daily vitamin D supplement of at least 400 IU or preferably 800 IU of vitamin D₃ can reduce the risk of fractures and probably also falls in elderly subjects, especially when combined with an optimal calcium intake. There is no formal proof of causality to define an optimal vitamin D intake or serum 25OHD based on its presumed extra skeletal health effects but the guidelines for bone health would probably eliminate also most negative extra skeletal health effects. The recommended vitamin D₃ supplement of 400-800 IU/d for adults also corresponds to the daily replacement dose calculated from metabolic clearance studies.

Adverse effects of ultraviolet radiation from the use of indoor tanning equipment: time to ban the tan

The incidence of melanoma skin cancer is increasing rapidly, particularly among young women in the United States. Numerous studies have documented an association between the use of indoor tanning devices and an increased risk of skin cancer, especially in young women. Studies have shown that ultraviolet exposure, even in the absence of erythema or burn, results in DNA damage. Countries and regulatory bodies worldwide have recognized the health risks associated with indoor tanning. In the United States, 32 states have passed legislation to regulate the indoor tanning industry, but there is an urgent need to restrict the use of indoor tanning devices at the federal level. The Food and Drug Administration is currently reviewing the classification of these devices. For all of these reasons, the Food and Drug Administration should prohibit the use of tanning devices by minors and reclassify tanning devices to at least class II to protect the public from the preventable cancers and other adverse effects caused by ultraviolet radiation from indoor tanning.

Interdependence between body surface area and ultraviolet B dose in vitamin D production: a randomized controlled trial

BACKGROUND

Ultraviolet (UV) B radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) [25(OH)D], but the relationship to body surface area and UVB dose needs investigation.

OBJECTIVE

To investigate the importance of body surface area and UVB dose on vitamin D production after UVB exposure.

METHODS

We randomized 92 participants to have 6%, 12% or 24% of their skin exposed to 0·75 (7·5 mJ cm(-2) at 298 nm using the CIE erythema action spectrum), 1·5 (15 mJ cm(-2) ) or 3·0 (30 mJ cm(-2) ) standard erythema doses (SED) of UVB. Each participant underwent four UVB exposures at intervals of 2-3 days. Skin pigmentation and 25(OH)D levels were measured before and 48 h after the final exposure.

RESULTS

The increase in 25(OH)D after irradiation [Δ25(OH)D] was positively correlated with body surface area (P = 0·006; R(2) = 0·08) and UVB dose (P < 0·0001; R(2) = 0·28), and negatively correlated with baseline 25(OH)D (P < 0·0001; R(2) = 0·18), for the entire data sample. However, when analysing each body surface area separately, we found a significant UVB response correlation for 6% (P < 0·0001; R(2) = 0·48) and 12% (P = 0·0004; R(2) = 0·35), but not for 24%. We also found a significant skin area response correlation for 0·75 SED (P < 0·0001; R(2) = 0·56), but not for 1·5 and 3·0 SED when analysing each UVB dose separately. The relationships did not change significantly after adjustment of Δ25(OH)D for baseline 25(OH)D.

CONCLUSION

The increase in 25(OH)D depends mainly on the UVB dose; however, for small UVB doses the area of irradiated body surface is important.

Ultraviolet radiation: a hazard to children and adolescents

Sunlight sustains life on earth. Sunlight is essential for vitamin D synthesis in the skin. The sun's ultraviolet rays can be hazardous, however, because excessive exposure causes skin cancer and other adverse health effects. Skin cancer is a major public health problem; more than 2 million new cases are diagnosed in the United States each year. Ultraviolet radiation (UVR) causes the 3 major forms of skin cancer: basal cell carcinoma; squamous cell carcinoma; and cutaneous malignant melanoma. Exposure to UVR from sunlight and artificial sources early in life elevates the risk of developing skin cancer. Approximately 25% of sun exposure occurs before 18 years of age. The risk of skin cancer is increased when people overexpose themselves to sun and intentionally expose themselves to artificial sources of UVR. Public awareness of the risk is not optimal, compliance with sun protection is inconsistent, and skin-cancer rates continue to rise in all age groups including the younger population. People continue to sunburn, and teenagers and adults are frequent visitors to tanning parlors. Sun exposure and vitamin D status are intertwined. Adequate vitamin D is needed for bone health in children and adults. In addition, there is accumulating information suggesting a beneficial influence of vitamin D on various health conditions. Cutaneous vitamin D production requires sunlight, and many factors complicate the efficiency of vitamin D production that results from sunlight exposure. Ensuring vitamin D adequacy while promoting sun-protection strategies, therefore, requires renewed attention to evaluating the adequacy of dietary and supplemental vitamin D. Daily intake of 400 IU of vitamin D will prevent vitamin D deficiency rickets in infants. The vitamin D supplementation amounts necessary to support optimal health in older children and adolescents are less clear. This report updates information on the relationship of sun exposure to skin cancer and other adverse health effects, the relationship of exposure to artificial sources of UVR and skin cancer, sun-protection methods, vitamin D, community skin-cancer-prevention efforts, and the pediatrician's role in preventing skin cancer. In addition to pediatricians' efforts, a sustained public health effort is needed to change attitudes and behaviors regarding UVR exposure.

Tanning as a behavioral addiction

BACKGROUND

Persistent tanning despite potentially fatal consequences suggests a compulsive behavior similar to other addictive disorders.

OBJECTIVES

To review the literature supporting tanning addiction from an epidemiological, behavioral, and neurobiological perspective.

METHODS

A comprehensive review of the medical literature was conducted to assess the health consequences of tanning, behaviors and other psychiatric disorders associated with tanning, and central rewarding effects of ultraviolet light.

RESULTS

Many frequent tanners endorse signs and symptoms adapted from Diagnostic and Statistical Manual-IV (DSM IV) substance abuse or dependence criteria. Recent studies suggest biochemical mechanisms may reinforce ultraviolet light seeking behavior.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

Frequent and persistent tanning may reveal itself to be a dermatologic-psychiatric disorder with carcinogenic sequelae. Multidisciplinary studies are required to determine the validity of an addiction diagnosis and to explore pharmacologic and cognitive therapeutic options for affected persons.

Holick's rule and vitamin D from sunlight

Holick's rule says that sun exposure 1/4 of a minimal erythemal dose (MED) over 1/4 of a body is equivalent to 1000 International Units (IU) oral vitamin D3. Webb and Engelsen recently commented that the ultraviolet (UV) spectrum used to establish Holick's rule is unknown. They consequently used a spring midday Boston solar spectrum to estimate ample sunlight exposures for previtamin D3 (preD3) at various locations. Literature review found the source upon which this rule is based was a fluorescent sunlamp (FS lamp). The FS spectrum is known and its relative weighting against the action spectra for erythema and the preD3 is significantly different from the solar spectrum used to derive the standard vitamin D effective dose (SDD). The preD3 effectiveness of the solar spectrum per unit erythemal hazard is greater than the FS lamp by a factor of 1.32. Consequently, UV exposure estimates based on Boston reference sunlight, instead of the UV lamp employed in the originating experiments, over estimate UV exposure equivalent to approximately 1000 IU orally by approximately 1/3. This redefinition of SDD impacts risk/benefit assessments of optimal/feasible sun exposure for vitamin D maintenance and the application of Holick's rule to rational public health messages.

Dr. Frank caldwell garland, june 20, 1950-august 17, 2010

Frank Caldwell Garland, Ph.D., died August 17, 2010 after a year-long battle with cancer. He will be remembered for his seminal work with his brother Cedric F. Garland in proposing the ultraviolet-B (UVB)-vitamin D-cancer hypothesis to explain the geographical variation of colon cancer mortality rates in the United States in 1980. This hypothesis has been extended to about 20 types of cancer using the ecological approach, and supported strongly by observational studies of prediagnostic serum 25-hydroxyvitamin D [25(OH) D] for incidence of breast, colorectal and ovarian cancer, and a randomized controlled trial that used sufficient vitamin D (1,150 IU/day) to and found a strongly beneficial effect on cancer incidence. The UVB-vitamin D-cancer hypothesis is also supported by studies that used as the index of solar UVB irradiance the amount of sunlight exposure in childhood or incidence of non-melanoma skin cancer. Survival after diagnosis was increased for individuals with higher serum 25(OH)D levels at the time of cancer diagnosis for six types of cancer: breast, colorectal, lung and prostate cancer; melanoma and non-Hodgkin's lymphoma. The ecological study approach is ideally suited to studying cancer risk-modifying factors since the lag between cancer initiation and detection or death can be 20-40 years or more, making ordinary observational studies difficult. The impact on vitamin D research by both Frank Garland and Cedric Garland has been immense. Health policy leaders will realize this in the near future, providing a rich legacy for humanity.

Vitamin D production after UVB exposure depends on baseline vitamin D and total cholesterol but not on skin pigmentation

UVB radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) (25(OH)D), but the influence of skin pigmentation, baseline 25(OH)D level, and total cholesterol has not been well characterized. To determine the importance of skin pigmentation, baseline 25(OH)D level, and total cholesterol on 25(OH)D production after UVB exposure, 182 persons were screened for 25(OH)D level. A total of 50 participants with a wide range in baseline 25(OH)D levels were selected to define the importance of baseline 25(OH)D level. Of these, 28 non-sun worshippers with limited past sun exposure were used to investigate the influence of skin pigmentation and baseline total cholesterol. The participants had 24% of their skin exposed to UVB (3 standard erythema doses) four times every second or third day. Skin pigmentation and 25(OH)D levels were measured before and after the irradiations. Total cholesterol was measured at baseline. The increase in 25(OH)D level after UVB exposure was negatively correlated with baseline 25(OH)D level (P<0.001) and positively correlated with baseline total cholesterol level (P=0.005), but no significant correlations were found with constitutive or facultative skin pigmentation. In addition, we paired a dark-skinned group with a fair-skinned group according to baseline 25(OH)D levels and found no differences in 25(OH)D increase after identical UVB exposure.

Older women and suntanning: the negotiation of health and appearance risks

This paper examines older women's experiences and perceptions of sunbathing, sun avoidance, and suntanned appearances. Using data from in-depth interviews with 36 women aged 71 to 94, we elucidate the motivations behind the women's sunbathing practices. Specifically, we explore how the women responded to the health and appearance risks associated with exposure to and avoidance of ultraviolet radiation as well as extant feminine beauty norms. The majority of women put their experiences of sunbathing in an emergent historical context. Although most of the women suggested that suntanned appearances were indicative of health and beauty, sunbathers tended to downplay their health risks by distancing themselves from those they considered to be most at risk, namely tanning bed users and individuals who acquired overly dark suntans. Sunbathers also emphasised the benefits of sun exposure for adequate vitamin D absorption. In contrast, the women who did not suntan tended to have experienced negative health and appearance consequences from their past sunbathing practices. Thus, these women emphasised the importance of future health over immediate appearance dividends. We discuss our findings in relation to the extant research on suntanning and the literature pertaining to health, risk, and beauty work.

Design and methods for a cluster randomized trial of the Sunless Study: a skin cancer prevention intervention promoting sunless tanning among beach visitors

Background

Skin cancer is the most prevalent yet most preventable cancer in the US. While protecting oneself from ultraviolet radiation (UVR) can largely reduce risk, rates of unprotected sun exposure remain high. Because the desire to be tan often outweighs health concerns among sunbathers, very few interventions have been successful at reducing sunbathing behavior. Sunless tanning (self-tanners and spray tans), a method of achieving the suntanned look without UVR exposure, might be an effective supplement to prevention interventions.

Methods and Design

This cluster randomized trial will examine whether a beach-based intervention that promotes sunless tanning as a substitute for sunbathing and includes sun damage imaging and sun safety recommendations is superior to a questionnaire only control group in reducing sunbathing frequency. Female beach visitors (N = 250) will be recruited from 2 public beaches in eastern Massachusetts. Beach site will be the unit of randomization. Follow-up assessment will occur at the end of the summer (1-month following intervention) and 1 year later. The primary outcome is average sunbathing time per week. The study was designed to provide 90% power for detecting a difference of .70 hours between conditions (standard deviation of 2.0) at 1-year with an intra-cluster correlation coefficient of 0.01 and assuming a 25% rate of loss to follow-up. Secondary outcomes include frequency of sunburns, use of sunless tanning products, and sun protection behavior.

Discussion

Interventions might be improved by promoting behavioral substitutes for sun exposure, such as sunless tanners, that create a tanned look without exposure to UVR.

Trial registration

NCT00403377

UV and pigmentation: molecular mechanisms and social controversies

Ultraviolet radiation (UVR) is an essential risk factor for the development of premalignant skin lesions as well as of melanoma and non-melanoma skin cancer. UVR exerts many effects on the skin, including tanning, carcinogenesis, immunomodulation, and production of vitamin D. Vitamin D (vit D) is important in the maintenance of healthy bones as well as other purported beneficial effects, amongst which is the potential for reducing risk of malignancy--though oral supplementation is fully capable of maintaining systemic levels. The known medical harm from UV exposure relates primarily to cancer of the skin--the most common organ in man to be affected by cancer. In this review, we summarize the knowledge about the ultraviolet (UV) response in regards to inflammation, immunosuppression, carcinogenesis and the tanning response. We also discuss vit D and UV, as well as public health implications of tanning behavior and commercial interests related to the promotion of UV exposure. As the most ubiquitous human carcinogen, UVR exposure represents both a challenge and enormous opportunity in the realm of skin cancer prevention.

From vitamin D to hormone D: fundamentals of the vitamin D endocrine system essential for good health

New knowledge of the biological and clinical importance of the steroid hormone 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] and its receptor, the vitamin D receptor (VDR), has resulted in significant contributions to good bone health. However, worldwide reports have highlighted a variety of vitamin D insufficiency and deficiency diseases. Despite many publications and scientific meetings reporting advances in vitamin D science, a disturbing realization is growing that the newer scientific and clinical knowledge is not being translated into better human health. Over the past several decades, the biological sphere of influence of vitamin D(3), as defined by the tissue distribution of the VDR, has broadened at least 9-fold from the target organs required for calcium homeostasis (intestine, bone, kidney, and parathyroid). Now, research has shown that the pluripotent steroid hormone 1alpha,25(OH)(2)D(3) initiates the physiologic responses of >/=36 cell types that possess the VDR. In addition to the kidney's endocrine production of circulating 1alpha,25(OH)(2)D(3,) researchers have found a paracrine production of this steroid hormone in >/=10 extrarenal organs. This article identifies the fundamentals of the vitamin D endocrine system, including its potential for contributions to good health in 5 physiologic arenas in which investigators have clearly documented new biological actions of 1alpha,25(OH)(2)D(3) through the VDR. As a consequence, the nutritional guidelines for vitamin D(3) intake (defined by serum hydroxyvitamin D(3) concentrations) should be reevaluated, taking into account the contributions to good health that all 36 VDR target organs can provide.

Sun safety: what are the health messages?

Solar ultraviolet radiation (UVR) is a human carcinogen. The UK and the worldwide incidence of cutaneous (skin) melanoma are rising. It is now the second most common cancer in 15-34 year-olds in the UK, increasing by 49% in 1991—2000. The UK government prioritized skin cancer in 1992 in their public health strategy The Health of the Nation, and set the target for reducing the yearly rise in skin cancer incidence by 2005. In 1998 in the Saving Lives: Our Healthier Nation strategy, targets were set to reduce the death rate from cancer, including skin cancer, by 20% by 2010. As a consequence of these targets, since the mid-1990s public health campaigns to reduce sun exposure and skin cancer incidence in the UK have used specific interventions for at-risk groups and the mass media to reach the general population. Evidence indicates a shift in knowledge, with further work required to increase change in behaviour and attitudes.

An associate health problem is vitamin D deficiency, which is prevalent across certain UK population groups. The main childhood health problem associated with vitamin D deficiency is the development of rickets, with evidence indicating those at high risk are exclusively breastfed dark-skinned infants, the elderly, those with dark skin pigmentation, and certain cultural groups that cover their bodies in clothing. Adolescents are the group with the highest incidence of low vitamin D status in the UK, with children of Asian descent at higher risk than Caucasian children. Increasing the outdoor activity levels of children in winter and during the cooler hours in summer is one way of increasing safe sun exposure. It is imperative to educate the general public on the risk of vitamin D deficiency, and offer advice on safe sun exposure, dietary sources of vitamin D, and dietary supplements. More research is required on recommendations for daily vitamin D supplements to determine optimal vitamin D levels in different population groups. There also needs to be reliable and accessible evidence on the links between vitamin D deficiency and lack of sun exposure, with sun safe messages adjusted accordingly.

Artificial and natural ultraviolet radiation exposure: beliefs and behaviour of 7200 French adults

BACKGROUND

Despite the increasing use of indoor tanning facilities, little is known regarding the behaviour of adults with respect to artificial and natural ultraviolet (UV) radiation exposure and the relationship between the two forms of exposure.

OBJECTIVES

To describe the beliefs and behaviour of French middle-aged volunteers regarding artificial and natural UV exposure.

METHODS

Cross-sectional study of a French national cohort using a self-completed questionnaire.

RESULTS

Participants were identified as 'indoor UV tanners' (n= 1076) and as 'non-users' (n= 6124). Predictor factors associated with indoor tanning were gender, age, smoking, phototype, region of residence, sun exposure during hobbies, voluntary sun exposure in particular during the hottest hours of the day, nudism practice, facial sunscreen habits, sunglass use, importance for lying in the sun and the claim 'ever heard of melanoma'.

LIMITATIONS

The quality of information may be limited by the data collection method.

CONCLUSION

Whereas indoor tanning should be discouraged, it seems that indoor tanners are also regular sunbathers unconcerned about the risk of photoageing and skin cancer occurrence. Moreover, indoor tanners seem to have more behavioural risk factors for cancer, such as smoking.

Update on sun protection and tanning in children

PURPOSE OF REVIEW

In this article we examine the latest information regarding pediatric sun protection and specifically focus on the impact of indoor tanning on children.

RECENT FINDINGS

We examine and discuss the prevailing views and trends on ultraviolet radiation exposure, sun protection and the attendant adverse health effects among children. We identify the challenges related to limiting ambient ultraviolet exposure in children. As children, particularly adolescents, gain an understanding of sun protection, their use of ultraviolet radiation protection does not increase concordantly. We discuss health policies regarding ultraviolet radiation protection, compliance with these policies and potential methods to increase compliance. We also examine addiction-like behavior and other psychosocial factors affecting those who are regular indoor tanners. Finally, we consider possible alternatives to ultraviolet radiation induced tanning and whether encouraging these options leads to a confusing, mixed message from healthcare providers.

SUMMARY

In this article we examine and discuss current practices, attitudes and recent trends in sun protection. We discuss indoor tanning, with special emphasis on the potential addictive qualities of ultraviolet radiation. Our goal is to identify opportunities and future directions to promote sun safety and protect children from harmful ultraviolet radiation exposure.