The sociological basis of the skin cancer epidemic.

Given the precipitous rise in its incidence in recent decades, skin cancer has been recognized as a growing epidemic. We explore the sociological underpinnings of this epidemic, including: (1) aging of the demographic; (2) human ecologic factors (residing in areas with high ambient ultraviolet levels and a depleted ozone layer); (3) large-scale European migration to more equatorial latitudes; (4) social structures that for centuries minimized miscegenation and maximized segregation; (5) gender-based differences in sunbathing, tanning, sunscreen use, and clothing choice; (6) occupational ultraviolet exposure; (7) the complex interplay of socioeconomic status, race, and urbanization on skin cancer incidence and mortality; (8) the effects of war on skin cancer incidence; (9) cultural shifts in clothing, travel, outdoor sports, recreation, and attitudes towards being tan; and (10) the indirect effects of religion. We show that without these sociological factors, the most common type of cancer would not be nearly as common.

Comparison of ultraviolet A light protection standards in the United States and European Union through in vitro measurements of commercially available sunscreens.

BACKGROUND: The importance of adequate ultraviolet A light (UVA) protection has become apparent in recent years. The United States and Europe have different standards for assessing UVA protection in sunscreen products. OBJECTIVE: We sought to measure the in vitro critical wavelength (CW) and UVA protection factor (PF) of commercially available US sunscreen products and see if they meet standards set by the United States and the European Union. METHODS: Twenty sunscreen products with sun protection factors ranging from 15 to 100+ were analyzed. Two in vitro UVA protection tests were conducted in accordance with the 2011 US Food and Drug Administration final rule and the 2012 International Organization for Standardization method for sunscreen effectiveness testing. RESULTS: The CW of the tested sunscreens ranged from 367 to 382 nm, and the UVA PF of the products ranged from 6.1 to 32. Nineteen of 20 sunscreens (95%) met the US requirement of CW >370 nm. Eleven of 20 sunscreens (55%) met the EU desired ratio of UVA PF/SPF > 1:3. LIMITATIONS: The study only evaluated a small number of sunscreen products. CONCLUSION: The majority of tested sunscreens offered adequate UVA protection according to US Food and Drug Administration guidelines for broad-spectrum status, but almost half of the sunscreens tested did not pass standards set in the European Union.

Skin cancer: role of ultraviolet radiation in carcinogenesis.

UV radiation is a carcinogen known to play a role in the development of non-melanoma and melanoma skin cancers. Acute and chronic exposure to UV radiation causes clinical and biological effects that promote the unregulated proliferation of skin cells. In recent decades, changes in climate and increased air pollution have led to environmental changes that increase UV light transmission. In this chapter, we discuss sources of UV radiation that are relevant to human health, as well as the acute and chronic effects that result from UV radiation exposure.

Sunscreens: a review of health benefits, regulations, and controversies.

Ultraviolet radiation plays a major role in the development of nonmelanoma and melanoma skin cancers. Photoprotection by sunscreens has been shown to prevent the development of actinic keratosis, squamous cell carcinoma, melanoma, and photoaging. However, these benefits are only derived if the users apply sunscreen appropriately and practice other sun protection measures. This review discusses the health benefits provided by sunscreen use, updates the latest regulatory landscape on sunscreen, and addresses the controversies and limitations associated with sunscreen use.

Photoprotection: part I. Photoprotection by naturally occurring, physical, and systemic agents.

The acute and chronic consequences of ultraviolet radiation on human skin are reviewed. An awareness of variations in naturally occurring photoprotective agents and the use of glass, sunglasses, and fabric can lead to effective protection from the deleterious effects of ultraviolet radiation. New systemic agents, including Polypodium leucotomos, afamelanotide, and antioxidants have potential as photoprotective agents.

Photoprotection: part II. Sunscreen: development, efficacy, and controversies.

In addition to the naturally occurring, physical, and systemic photoprotective agents reviewed in part I, topical ultraviolet radiation filters are an important cornerstone of photoprotection. Sunscreen development, efficacy, testing, and controversies are reviewed in part II of this continuing medical education article.

Current status of photoprotection by window glass, automobile glass, window films, and sunglasses.

Ultraviolet radiation (UVR) has known adverse effects on the skin and eyes. Practitioners are becoming more aware of the importance of outdoor photoprotection. However, little attention is directed to the exposure of the skin and eyes to UVR through the window glass or sunglasses. The amount of ultraviolet transmission through glass depends mainly on the type of the glass. All types of commercial and automobile glass block the majority of ultraviolet-B; however, the degree of ultraviolet-A transmission depends on the type of glass. Laminated glass offers better UVA protection than tempered glass; new safety regulations for automobiles may result in increased use of laminated glass for side windows. Window films can be applied to glass to increase UVR protection. Sunglasses need to be compliant with one of the national standards; a wraparound style or side shields offer the best protection. Increased understanding by practitioners on the transmission of UVR through glass, window films, and sunglasses would allow them to better educate the public and to better manage photosensitive patients.

The evolution of sunscreen products in the United States--a 12-year cross sectional study.

Excessive exposure from ultraviolet (UV) radiation contributes to the development of skin cancers and photoaging. Topical sunscreen products remain one of the most widely used forms of protection for the majority of the public. The objective of this analysis was to examine photoprotection trends (e.g., SPF value) and the degree of UVA I protection from 1997 to 2009 in the United States. Sunscreen products purchased and evaluated in 1997 (N = 59), 2003 (N = 188) and again in 2009 (N = 330), totaling 577, were included in this analysis. Information regarding (1) the SPF value, (2) name and concentration of the active ingredients, (3) type of products (i.e., daily vs. recreational/beach), and (4) claims of UVA protection was recorded and analyzed. In addition, the critical wavelength (CW) of 330 products from 2009 was determined. The results showed an increase in the SPF values of products from 1997 to 2009. The percentage of low SPF products (SPF 4-14) decreased from 27% in 1997 to 6% in 2009. The number of products containing a known UVA-I filter (i.e., avobenzone or zinc oxide) increased from 5% in 1997 to 70% in 2009. Lastly, approximately, 225 (68%) of the products tested in 2009 attained CW > 370 nm. In the past decade, sunscreen products have undergone fundamental improvements, the most significant of which is the breadth of protection against UVA I.

From the bottle to the skin: challenges in evaluating antioxidants.

Endogenous production and ultraviolet-generated free radicals in the skin can lead to photoaging and even skin cancer. Topical antioxidants have been found to provide benefits against ultraviolet damage and these ingredients have been incorporated into various cosmetic products and claimed to have substantial effects. Currently, there is a lack in a standardized rating system to measure the concentration and activity levels of antioxidants in these products. As a result, it is difficult for consumers and clinicians to evaluate and select commercial products based on readily accessible evidence. In this review, we will describe four assays which have been used to measure antioxidants in various products, and the strengths and weaknesses of each test will be detailed. We will highlight key considerations for clinicians when interpreting the results of antioxidant tests when evaluating commercial products containing antioxidants.

Sunscreens: obtaining adequate photoprotection.

Adequate photoprotection plays a paramount role in reducing the burden of both photoaging and photocarcinogenesis. The scope of photoprotective strategies employed by the public, from most to least effective, includes: sun avoidance, seeking shade, the use of protective clothing, and the application of sunscreen. Among these options, sunscreen use remains the strategy most frequently employed by the public--a reversal of the preferred order of photoprotection. Given this trend, it is clear why sunscreens invariably take center stage in any discussion regarding obtaining adequate photoprotection.