An analysis of cumulative lifetime solar ultraviolet radiation exposure and the benefits of daily sun protection

A survey of sun safety habits among Division I National Collegiate Athletic Association golfers and tennis players

Collegiate athletes who play tennis and golf spend significant time outdoors and increase their risk of skin cancer. This study aimed to gain insight into the sun protection behaviors of collegiate golfers and tennis players competing in the National Collegiate Athletic Association (NCAA) Division I. A survey was distributed to NCAA Division I golf and tennis teams within Power 5 collegiate conferences. Of the 84 respondents, 50% indicated sunscreen use more than 75% of the time while playing their sport, but only 4.8% engaged in sunscreen reapplication. The main barriers to reapplication were due primarily to slippery hands (70.2%) or forgetfulness (63.4%). Most athletes do not apply sunscreen to hands, ears, chest, or lips, and either never or rarely wear sunscreen while outside when they are not playing their sport (54.8%). Thirty-three percent were unsure or did not believe they were at an increased risk for skin cancer, and 16.6% were unsure or did not believe that sunscreen can prevent skin cancer. Most collegiate athletes recognize their increased risk of skin cancer; nevertheless, they are unlikely to reapply sunscreen and often do not apply sunscreen to commonly missed areas. Increased education and resources may help promote lifelong safe sun exposure habits and reduce skin cancer risk.

Application habits and practices of regular sunscreen users in the United States: Results of an online survey

A nationwide online survey assessed claimed usage of sunscreen products in 2283 self-identified regular sun protection factor (SPF) consumers (RSPFC) in the United States. Subjects applied sunscreen most frequently when spending more than 3 h in the sun. Sunscreen usage peaks during the summer, with sunny weather prompting 99% usage of beach/recreational SPF products but drops to approximately 50% and 30% on partly cloudy and cloudy days, respectively, regardless of SPF product category. About half of RSPFC augment sunscreen product usage by limiting time in the sun and wearing a hat. SPF products are not reapplied by approximately 20-60% of RSPFC, depending upon product category, and reapplication was less than 33% on cloudy and partly cloudy days. Primary reasons for reapplication were water exposure, number of hours in the sun, and being active/sweating, most notably for beach/recreational SPF products. Importantly, in children, 45% of parents reported "redness" as a signal for reapplying sunscreen product. Only 10% of respondents correctly identified sunscreen products as drugs. Based on these results, while sunscreens may share common ingredients and efficacy measures, their usage by consumers varies widely depending on product type, season, weather, gender, age, and geographical location.

Sunscreens - another endangered species?

Skin cancer continues to increase in incidence year-on-year and represents the most common form of cancer across the globe. Every human undergoes premature ageing, particularly on the face, neck and hands. Both phenomena are driven primarily by chronic, daily exposure to solar ultraviolet radiation (UVR). While sunscreen products play a primary role in the prevention of UVR skin damage, the active ingredients, i.e., UVR filters, are facing unprecedented challenges in the coming 10 years and their future is by no means certain. This article, therefore, reviews afresh the facts around photoprotection and the role of sunscreen products in the prevention of acute (sunburn) and chronic (cancer, photoageing) skin damage and compares/contrasts these with various emerging questions and opinions around UVR filter technology. We present a passionate defence of this remarkable technology, but also attempt to imagine a world without it.

Prevalence and Correlates of Observed Sun Protection Behaviors Across Different Public Outdoor Settings in Melbourne, Australia

Skin cancer prevention efforts in Australia have increasingly incorporated a focus on protection during incidental sun exposure. This complements the long-present messages promoting protection in high-risk settings and avoidance of acute intense bouts of sun exposure. Data from two waves of a cross-sectional direct observational survey was used to assess the prevalence and correlates of N = 12,083 adolescents' and adults' sun protection behavior (arm and leg cover, hat, sunglasses, and shade cover). Individuals were observed in public outdoor settings in Melbourne, Australia during peak ultraviolet (UV) times (11 a.m.-3 p.m.) on summer weekends. Settings included pools and beaches, parks and gardens, and for the first time in 2018, outdoor streets and cafés which may capture more incidental forms of sun exposure and represent another public setting where Australians commonly spend time outdoors. Females and older adults were consistently better protected than males and adolescents. Physical activity was strongly associated with low shade cover across settings. Weather was more strongly associated with sun protection at outdoor streets/cafes and parks/gardens than at pools/beaches but use of observed sun protection (particularly arm cover and covering hat) was low across settings. Continued public education about UV risk and its relation to weather and the seasons is needed to promote the routine use of multiple forms of sun protection during outdoor activities in peak UV times, especially among males and adolescents. Findings also highlight the importance of considering activity demands of public spaces in shade planning to optimize sun protection during outdoor activities in public spaces.

Dispelling myths about sunscreen

Sunscreens are an important tool used to protect the skin against harmful effects of ultraviolet (UV) radiation. Many different formulations of sunscreen exist today, which can be confusing to the consumer. In this article, we highlight and address many sunscreen myths that exist today including the benefits of higher SPF sunscreen, use of sunscreen in darker skin types, and the effects of sunscreen on vitamin D production.

Predictors of Sunburn Risk Among Florida Residents

Context: The incidence of skin cancer, the most common type of cancer in the United States, is increasing. Sunburn is a major modifiable risk factor for skin cancer, and its prevalence among the US population is high.

Objectives: To identify predictors of having had a red or painful sunburn in the past 12 months among people living in Florida.

Methods: Florida residents were recruited from public places and online. They were asked to complete an anonymous cross-sectional survey that assessed demographic information, dermatologic history, as well as knowledge, attitude, and behavior factors associated with sunburn.

Results: A total of 437 participants whose data were complete for all variables were included in the multivariate analysis. In multivariate logistic regression, younger age (18-29 years) was the most significant predictor of sunburn (OR, 15.26; 95% CI, 5.97-38.98; P<.001). Other significant predictors included identifying as nonwhite (OR, 0.51; 95% CI, 0.29-0.90; P<.02), having had a full-body skin examination by a physician (OR, 1.8; 95% CI, 1.03-3.14; P<.04), reporting higher levels of skin sensitivity to the sun (OR, 4.63; 95% CI, 2.07-10.34; P<.001), having a less favorable attitude toward sun protection (OR, 0.88; 95% CI, 0.81-0.94; P<.001), having high perceived vulnerability to skin cancer (OR, 1.21; 95% CI, 1.05-1.41; P<.009), and spending less than 1 hour outside between 10 am and 4 pm on weekends (OR, 0.46; 95% CI, 0.22-0.96; P<.04). The model was statistically significant at P<.001 and correctly classified 78% of participants.

Conclusions: Sunburn prevention programs that osteopathic physicians can readily implement in clinical practice are urgently needed, particularly for young adult patients. This study identified 7 predictors of sunburn in Florida residents. With additional research findings, promoting attitude change toward sun protection may be a viable strategy.

Extracts of Morus nigra L. Leaves Standardized in Chlorogenic Acid, Rutin and Isoquercitrin: Tyrosinase Inhibition and Cytotoxicity

Melanogenesis is a process responsible for melanin production, which is stored in melanocytes containing tyrosinase. Inhibition of this enzyme is a target in the cosmetics industry, since it controls undesirable skin conditions such as hyperpigmentation due to the overproduction of melanin. Species of the Morus genus are known for the beneficial uses offered in different parts of its plants, including tyrosinase inhibition. Thus, this project aimed to study the inhibitory activity of tyrosinase by extracts from Morus nigra leaves as well as the characterization of its chromatographic profile and cytotoxicity in order to become a new therapeutic option from a natural source. M. nigra leaves were collected, pulverized, equally divided into five batches and the standardized extract was obtained by passive maceration. There was no significant difference between batches for total solids content, yield and moisture content, which shows good reproducibility of the extraction process. Tyrosinase enzymatic activity was determined for each batch, providing the percentage of enzyme inhibition and IC₅₀ values obtained by constructing dose-response curves and compared to kojic acid, a well-known tyrosinase inhibitor. High inhibition of tyrosinase activity was observed (above 90% at 15.625 μg/mL). The obtained IC₅₀ values ranged from 5.00 μg/mL ± 0.23 to 8.49 μg/mL ± 0.59 and were compared to kojic acid (3.37 μg/mL ± 0.65). High Performance Liquid Chromatography analysis revealed the presence of chlorogenic acid, rutin and, its major compound, isoquercitrin. The chromatographic method employed was validated according to ICH guidelines and the extract was standardized using these polyphenols as markers. Cytotoxicity, assessed by MTT assay, was not observed on murine melanomas, human keratinocytes and mouse fibroblasts in tyrosinase IC₅₀ values. This study demonstrated the potential of M. nigra leaf extract as a promising whitening agent of natural source against skin hyperpigmentation.

Superoxide dismutase 1 inhibits alpha-melanocyte stimulating hormone and ultraviolet B-induced melanogenesis in murine skin

Background

Over the last decade, the incidence of ultraviolet B (UVB)-related skin problems has increased. Oxidative stress caused by UVB induces the secretion of melanocyte growth and activating factors from keratinocytes, which results in the formation of cutaneous hyperpigmentation. Therefore, increasing the antioxidant abilities of skin cells is thought to be a beneficial strategy for the development of sunscreen agents. Superoxide dismutase 1 (SOD1) is an antioxidant enzyme that is known to exhibit antioxidant properties.

Objective

The purpose of this study was to investigate the effect of SOD1 on alpha-melanocyte stimulating hormone (α-MSH) and UVB-induced melanogenesis in B16F10 melanoma cells and HRM-2 melanin-possessing hairless mice.

Methods

The inhibitory effect of SOD1 on tyrosinase activity was evaluated in a cell-free system. Additional experiments were performed using B16F10 melanoma cells to demonstrate the effects of SOD1 in vitro, and HRM-2 melanin-possessing hairless mice were used to evaluate the antimelanogenic effects of SOD1 in vivo.

Results

We found that SOD1 inhibited melanin production in a dose-dependent manner without causing cytotoxicity in B16F10 melanoma cells. SOD1 did not inhibit tyrosinase activity under cell-free conditions. The results indicate that SOD1 may reduce pigmentation by an indirect, nonenzymatic mechanism. We also found that SOD1 decreased UVB-induced melanogenesis in HRM-2 melanin-possessing hairless mice, as visualized through hematoxylin and eosin staining and Fontana-Masson staining.

Conclusion

Our results indicate that SOD1 has an inhibitory effect on α-MSH and UVB-induced melanogenesis, indicating that SOD1 may be a promising sunscreen agent.

Prevalence of sun exposure and its associated factors in southern Brazil: a population-based study

BACKGROUND

Sunlight exposure is responsible for a large number of dermatological diseases.

OBJECTIVE

We estimated the prevalence of sunlight exposure and its associated factors in adults from southern Brazil in a cross-sectional, population-based study.

METHODS

We investigated a representative sample of individuals aged ≥ 20 years (n=3,136). Sunlight exposure and its associated factors were evaluated in two distinct situations: at leisure time and at work. The time period investigated ranged from December 2004 to March 2005, comprising 120 days of the highest ultraviolet index in the urban area of the city of Pelotas, in southern Brazil. The participants were asked about sunlight exposure for at least 20 minutes between 10 A.M. and 4 P.M. The analysis was stratified by sex, and sunlight exposure was grouped into five categories.

RESULTS

Among the 3,136 participants, prevalence of sunlight exposure at the beach was 32.8% (95% CI, 30.3 - 35.2) and 26.3% (95% CI, 24.2 28.3) among men and women, respectively. The prevalence at work was 39.8% (95% CI, 37.2 - 42.4) among men and 10.5% (95% CI, 9.1 - 12.0) among women. Age was inversely associated with sunlight exposure. Family income and achieved schooling were positively associated with sunlight exposure at leisure time and inversely associated with sunglight exposure at work. Self-reported skin color was not associated. Knowledge of any friend or relative who has been affected by skin cancer was positively associated with sunlight exposure among men at work.

CONCLUSION

Despite the media campaigns on the harmful effects of excessive sunlight exposure, we found a high prevalence of sunlight exposure during a period of high ultraviolet index.

Combined radiation and burn injury results in exaggerated early pulmonary inflammation

Events such as a nuclear meltdown accident or nuclear attack have potential for severe radiation injuries. Radiation injury frequently occurs in combination with other forms of trauma, most often burns. Thus far, combined injury studies have focused mainly on skin wound healing and damage to the gut. Since both radiation exposure and remote burn have pulmonary consequences, we examined the early effects of combined injury on the lung. C57BL/6 male mice were irradiated with 5 Gy of total body irradiation followed by a 15% total body surface area scald burn. Lungs from surviving animals were examined for evidence of inflammation and pneumonitis. At 48 h post-injury, pathology of the lungs from combined injury mice showed greater inflammation compared to all other treatment groups, with marked red blood cell and leukocyte congestion of the pulmonary vasculature. There was excessive leukocyte accumulation, primarily neutrophils, in the vasculature and interstitium, with occasional cells in the alveolar space. At 24 and 48 h post-injury, myeloperoxidase levels in lungs of combined injury mice were elevated compared to all other treatment groups (P < 0.01), confirming histological evidence of neutrophil accumulation. Pulmonary levels of the neutrophil chemoattractant KC (CXCL1) were 3 times above that of either injury alone (P < 0.05). Further, monocyte chemotactic protein-1 (MCP-1, CCL2) was increased two- and threefold compared to burn injury or radiation injury, respectively (P < 0.05). Together, these data suggest that combined radiation and burn injury augments early pulmonary congestion and inflammation. Currently, countermeasures for this unique type of injury are extremely limited. Further research is needed to elucidate the mechanisms behind the synergistic effects of combined injury in order to develop appropriate treatments.

Geographical distribution of adolescent body height with respect to effective day length in Japan: an ecological analysis

The height of Japanese youth raised in the northern region tends to be greater than that of youth raised in the southern region; therefore, a geographical gradient in youth body height exists. Although this gradient has existed for about 100 years, the reasons for it remain unclear. Consideration of the nutritional improvement, economic growth, and intense migration that has occurred in this period indicates that it is probably the result of environmental rather than nutritional or genetic factors. To identify possible environmental factors, ecological analysis of prefecture-level data on the body size of 8- to 17-year-old youth averaged over a 13-year period (1996 to 2008) and Japanese mesh climatic data on the climatic variables of temperature, solar radiation, and effective day length (duration of photoperiod exceeding the threshold of light intensity) was performed. The geographical distribution of the standardized height of Japanese adolescents was found to be inversely correlated to a great extent with the distribution of effective day length at a light intensity greater than 4000 lx. The results of multiple regression analysis of effective day length, temperature, and weight (as an index of food intake) indicated that a combination of effective day length and weight was statistically significant as predictors of height in early adolescence; however, only effective day length was statistically significant as a predictor of height in late adolescence. Day length may affect height by affecting the secretion of melatonin, a hormone that inhibits sexual and skeletal maturation, which in turn induces increases in height. By affecting melatonin production, regional differences in the duration of the photoperiod may lead to regional differences in height. Exposure to light intensity greater than 4000 lx appears to be the threshold at which light intensity begins to affect the melatonin secretion of humans who spend much of their time indoors.

Photoprotection against the UVB-induced oxidative stress and epidermal damage in mice using leaves of three different varieties of Lepidium meyenii (maca)

BACKGROUND

Skin exposure to ultraviolet (UV) B radiation leads to epidermal damage and generation of reactive oxygen species. The photoprotective effect of extracts of three varieties of leaves (red, yellow, and black) from maca (Lepidium meyenii), a plant from the Peruvian highlands, was assessed in mouse skin exposed to UVB radiation.

MATERIALS AND METHODS

The hydroalcoholic extracts of three varieties of maca leaves were applied topically to the dorsal skin of young-adult male mice prior to exposition to UVB radiation.

RESULTS

The three varieties had UVA/UVB absorptive properties and presented antioxidant activity, being highest with red maca, followed by black and yellow maca. The three varieties of maca leaves prevented the development of sunburn cells, epidermal hyperplasia, leukocytic infiltration, and other alterations produced by UVB radiation. Mice treated with black maca showed the highest superoxide dismutase levels, and mice treated with black and yellow maca showed higher catalase levels in skin, whereas red maca protected the skin and liver against significant increases in the lipid peroxidation activity observed in the unprotected animals.

CONCLUSION

The presence of significant antioxidant activity and the inhibition of lipid peroxidation suggest that the observed protection could be partly attributable to this mechanism.

Sun protection intervention for highway workers: long-term efficacy of UV photography and skin cancer information on men's protective cognitions and behavior

Background

The risk for skin cancer is increased among older males and outdoor workers who have high levels of ultraviolet (UV) exposure.

Purpose

This study was designed to examine the long-term efficacy of UV photography interventions on male outdoor workers, the potential mediators of its impact, and the efficacy of UV photography and skin cancer vs. aging information with this population.

Methods

One hundred forty-eight male outdoor workers were randomly assigned to one of four intervention conditions or a control condition in a two by two plus one factorial design. The men in the intervention conditions received or did not receive a UV photo of their face and watched either a photoaging or skin cancer educational video. Participants completed pre-intervention, immediate post-intervention, and 2-month and 1-year follow-up assessments.

Results

Analysis of covariance and structural equation modeling revealed that participants in the UV photography and cancer information interventions reported higher levels of sun protection cognitions, which were significant partial mediators of increases in sun protection behaviors and decreases in skin color.

Conclusions

This study provides evidence for effective sun protection interventions on male outdoor workers that may help reduce skin cancer risk.

Knowledge, attitudes, and behaviors of elementary school students regarding sun exposure and skin cancer

The aim of this study was to assess baseline knowledge of skin cancer, sun protection practices, and perceptions of tanning among third through fifth grade elementary students in Florida. A total of 4,002 students in nineteen elementary schools in Palm Beach County, Florida were surveyed. SunSmart America curriculum pretest responses were the main outcome measures. Overall students' knowledge using a students' mean knowledge scale scores of skin cancer and sun protection were low (<40% of questions answered correctly) and was found to increase with increasing grade level (p < 0.01). Boys more frequently reported spending greater than 2 hours in the sun when compared with girls (p < 0.01). Girls, however, were more likely to try and get a tan most of the time or always when compared with boys (p = 0.02). Non-Hispanic White students (51.3%) more frequently reported use of SPF 15 or greater sunscreen "most of the time or always" compared with Hispanic (35.3%) and non-Hispanic Black (13.4%) students (p < 0.01). Elementary aged students in south Florida have limited knowledge about sun safety, despite spending considerable amount of time in the sun. Sun safe behavior is associated with gender and ethnicity. The findings provide empirical support for the need of a school-based educational intervention.

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.

Lichtschutz: Moglichkeiten und Grenzen. Sunprotection: Possibilities and limitations

Protection against ultraviolet (UV) irradiation prevents from the development of acute skin damage such as erythema formation and chronic skin changes such as premature skin ageing. Especially those sunscreens with higher sun protection factors do not only protect against solar dermatitis but also inhibit UV-induced immunosuppression by blocking the release of immunosuppressive mediators from UV-exposed epidermis. In particular, the protection against UV-induced immunosuppression by sunscreens is supposed to reduce the development of UV-induced skin cancer. Besides immunosuppression UV-irradiation is also able to induce "UV signature" mutations within UV-exposed DNA. Topical application of DNA repair enzymes induces nucleotide excision repair and corrections of DNA damages. Thereby, the risk to develop UV-induced skin malignancies is markedly reduced. Accordingly, future perspectives in the development of sunscreens include DNA repair enzymes or factors, which can induce the endogenous cellular DNA repair system. Until these developments come to practice reasonable sun protection according to the skin complexion is of primary importance.

The sensitivity of children to electromagnetic fields

In today's world, technologic developments bring social and economic benefits to large sections of society; however, the health consequences of these developments can be difficult to predict and manage. With rapid advances in electromagnetic field (EMF) technologies and communications, children are increasingly exposed to EMFs at earlier and earlier ages. Consistent epidemiologic evidence of an association between childhood leukemia and exposure to extremely low frequency (ELF) magnetic fields has led to their classification by the International Agency for Research on Cancer as a "possible human carcinogen." Concerns about the potential vulnerability of children to radio frequency (RF) fields have been raised because of the potentially greater susceptibility of their developing nervous systems; in addition, their brain tissue is more conductive, RF penetration is greater relative to head size, and they will have a longer lifetime of exposure than adults. To evaluate information relevant to children's sensitivity to both ELF and RF EMFs and to identify research needs, the World Health Organization held an expert workshop in Istanbul, Turkey, in June 2004. This article is based on discussions from the workshop and provides background information on the development of the embryo, fetus, and child, with particular attention to the developing brain; an outline of childhood susceptibility to environmental toxicants and childhood diseases implicated in EMF studies; and a review of childhood exposure to EMFs. It also includes an assessment of the potential susceptibility of children to EMFs and concludes with a recommendation for additional research and the development of precautionary policies in the face of scientific uncertainty.