Are tanning beds "safe"? Human studies of melanoma

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.

Photocarcinogenesis: an epidemiologic perspective on ultraviolet light and skin cancer

Photocarcinogenesis is the result of a complex interplay between ultraviolet radiation, DNA damage, mutation formation, DNA repair, apoptosis, and the immune system. Recent trends show an increase in incidence of both melanoma and nonmelanoma skin cancers. Some individuals have a genetic predisposition toward increased risk for skin cancer, whereas others experience increased risk through ultraviolet exposure and subsequent mutation formation. The initiation and propagation pathways of melanoma and nonmelanoma skin cancers differ but have some elements in common. The increase in incidence of skin cancer has been discovered to vary among age groups and gender.

Contribution of UVA irradiance to the erythema and photoaging effects in solar and sunbed exposures

Even though UVA irradiance had not been considered detrimental to human skin for years, nowadays it is recognized for its role in photoaging and other biological responses. The ratio UVA/UVB is about 17 at a solar zenith angle (SZA) of 20° and it is almost constant up to 60° when it rapidly increases since the UVB wavelengths (280-320nm) are more attenuated than the UVA waveband (320-400nm). For a constant SZA, the ratio increases with the ozone content. The UVA component of the solar erythemal irradiance ranges from 20% at 20° to 30% at 60°, whereas it varies from 50% to 80% in the two different types of measured sunbeds. Moreover, the different spectral distribution of the lamps used for artificial tanning leads frequently to high UVA doses. The biological responses related to skin photoaging (skin sagging and elastosis) could be around fourfold the equivalent solar irradiance at midday in summer midlatitudes and they can be important in unprotected UVA exposures to sunbeds. The UVA dose accumulated during the time required in reaching 1 minimum erythemal dose (MED) increases with the SZA since the exposure durations are longer. Indeed, seasonal differences in the mean UVA dose are observed due to variations in the ozone content that results in longer exposure times without erythema. Although an artificial tanning session is usually shorter than one hour, the UVA dose from sunbeds during the time for 1 MED for skin type II (250Jm(-2)) can be 2-4 times larger than the solar dose, depending on the lamp spectral emission.

A simple intervention to reinforce awareness of tanning bed use and skin cancer in non-medical skin care professionals in Southern California

BACKGROUND

(i) To assess the baseline knowledge of non-medical skin care professionals (estheticians, cosmetologists, massage therapists) on tanning bed use and its association with melanoma; and (ii) to provide preliminary evidence of the potential impact of a fast and simple educational intervention on tanning beds and melanoma on the awareness of non-medical skin care professionals towards skin cancer prevention.

METHODS

A pre-intervention survey was administered to non-medical skin care professional at salons or spas in Southern California to assess baseline knowledge on tanning and skin cancer. This was followed immediately by a 10-minute oral presentation on tanning bed use and its association with melanoma. One month later, a post-intervention survey was distributed to individuals who attended the initial oral presentation.

RESULTS

Significant changes pre- and post-intervention were found in non-medical skin care professionals' answer responses to the following: (i) increased speaking to clients about cancer risk with tanning bed use 42-66% (OR 2.44; 95% CI 1.39, 4.30)]; (ii) decreased personal tanning bed use (23-15% [OR 0.61; 95% CI 0.37, 1.00]); and (iii) decreased belief that tanning beds are an excellent cosmetic tool (29-20% [OR 0.60; 95% CI 0.38, 0.96]).

CONCLUSION

This study provides preliminary evidence that non-medical skin care professionals could be an important source of primary prevention information for reducing the burden of melanoma.

A dermatologist's perspective on vitamin D

Vitamin D is a fat-soluble steroid hormone that is crucial for human health and has recently generated controversy regarding its role in human health and disease. In this Special Article, we discuss our dermatologic perspective on vitamin D in a question-and-answer format. We discuss methods of obtaining vitamin D, including cutaneous photobiosynthesis, diet, and supplements and include the recent US Institute of Medicine recommendations. Other reviewed topics include the associations among skin pigmentation, climate, photoprotection, and vitamin D levels. We also elaborate on the popular interest in sun exposure as a method of normalizing vitamin D levels in the context of the risks of solar and artificial radiation. We also discuss groups at risk for vitamin D inadequacy, the need for testing serum vitamin D levels, and the role of phototherapy in patients with malabsorption conditions and hypervitaminosis D, with a focus on patients with sarcoidosis. Finally, we summarize our recommendations on vitamin D.

The deceptive nature of UVA tanning versus the modest protective effects of UVB tanning on human skin

The relationship between human skin pigmentation and protection from ultraviolet (UV) radiation is an important element underlying differences in skin carcinogenesis rates. The association between UV damage and the risk of skin cancer is clear, yet a strategic balance in exposure to UV needs to be met. Dark skin is protected from UV-induced DNA damage significantly more than light skin owing to the constitutively higher pigmentation, but an as yet unresolved and important question is what photoprotective benefit, if any, is afforded by facultative pigmentation (i.e. a tan induced by UV exposure). To address that and to compare the effects of various wavelengths of UV, we repetitively exposed human skin to suberythemal doses of UVA and/or UVB over 2 weeks after which a challenge dose of UVA and UVB was given. Although visual skin pigmentation (tanning) elicited by different UV exposure protocols was similar, the melanin content and UV-protective effects against DNA damage in UVB-tanned skin (but not in UVA-tanned skin) were significantly higher. UVA-induced tans seem to result from the photooxidation of existing melanin and its precursors with some redistribution of pigment granules, while UVB stimulates melanocytes to up-regulate melanin synthesis and increases pigmentation coverage, effects that are synergistically stimulated in UVA and UVB-exposed skin. Thus, UVA tanning contributes essentially no photoprotection, although all types of UV-induced tanning result in DNA and cellular damage, which can eventually lead to photocarcinogenesis.

[Solaria, vitamin D, and skin cancer]

BACKGROUND

Some researchers have suggested to use an indoor tanning device (solarium) as a vitamin D source for disease prevention.

MATERIAL AND METHODS

The article is based on non-systematic searches in PubMed and ISI, and the authors' experience from epidemiologic research and studies of solarium irradiance.

RESULTS

Vitamin D deficiency is an established risk factor for rickets in children and osteomalacia in adults; and is associated with an increased risk of osteoporosis and fractures. Several studies have found a beneficial role of vitamin D on both incidence and prognosis for other diseases, e.g. cancer, but causal relationships with vitamin D cannot yet be concluded. Sun exposure, our main source of vitamin D, is also an established risk factor of skin cancer. Moderate sun exposure generally provides an adequate amount of vitamin D during summer. Dietary intake of vitamin D is adamant when sun exposure is low. Solarium use seems to increase. Mean irradiance from solariums is higher than that from the summer sun in Oslo; 1.5 times higher for UVB and 3.5 times for UVA . Use of solarium increases the risk of skin cancer and was classified as carcinogenic to humans in 2009; positive health effects are not sufficiently documented.

INTERPRETATION

Recommendations on restricted solarium use should be maintained.

Changes in skin tanning attitudes. Fashion articles and advertisements in the early 20th century

Historical reviews suggest that tanning first became fashionable in the 1920s or 1930s. To quantitatively and qualitatively examine changes in tanning attitudes portrayed in the popular women's press during the early 20th century, we reviewed summer issues of Vogue and Harper's Bazaar for the years 1920, 1927, 1928, and 1929. We examined these issues for articles and advertisements promoting skin tanning or skin bleaching and protection. We found that articles and advertisements promoting the fashionable aspects of tanned skin were more numerous in 1928 and 1929 than in 1927 and 1920, whereas those promoting pale skin (by bleaching or protection) were less numerous. These findings demonstrate a clear shift in attitudes toward tanned skin during this period.

Melanoma epidemiology and public health

This article reviews the research on, and examines the epidemiology and prevention of melanoma. Despite the great quantity of research into environmental and genetic causes, and the ease of diagnosis, incidence and mortality have risen in all developed countries during the last half century. Patient and physician education, and public health programs aimed at prevention, have had varied success. The authors conclude that, until we have better data on how to prevent skin cancer of all types, the best solutions are education of high-risk populations about skin self-evaluation in combination with physician examination to practice; and sun protection.