Point: Sunscreen Use Is a Safe and Effective Approach to Skin Cancer Prevention

Sunscreens With High Versus Low Sun Protection Factor and Cutaneous Squamous Cell Carcinoma Risk: A Population-Based Cohort Study

Evidence on sunscreen use and cutaneous squamous cell carcinoma (cSCC) risk is limited. Most studies have not taken sun protection factor (SPF) into consideration and used nonusers of sunscreen as the reference group. Nonusers are likely a priori at lower cSCC risk than users. No study has investigated the effect of high- versus low-SPF sunscreens on cSCC, appropriately adjusting for time-varying confounding. Using data from the Norwegian Women and Cancer Study (1991–2016), we investigated whether use of SPF ≥15 versus SPF <15 sunscreens reduces cSCC risk. We used a marginal structural Cox proportional hazards model with inverse probability of treatment and censoring weights to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). During follow-up of 148,781 women (mean follow-up, 14.3 years), 653 women were diagnosed with cSCC. The effect on cSCC risk of sunscreens with SPF ≥15 versus SPF <15 was close to the null when used at any latitudes (HR = 1.02, 95% CI: 0.82, 1.27) and when used in lower-latitude settings (HR = 1.05, 95% CI: 0.84, 1.32). In conclusion, we found no indication that sunscreens with SPF ≥15 reduced Norwegian women’s cSCC risk more than sunscreens with SPF <15, suggesting that either there is no difference in their effects long-term or the difference is diluted by incorrect application.

Evaluation of the acceptance and efficacy of a bespoke sun protection package for persons with oculocutaneous albinism living in Malawi

INTRODUCTION

Skin cancer is the main cause of death in persons with albinism (PWA) in Africa. Education would minimize sun damage.

OBJECTIVE

To evaluate the efficacy and acceptance of a photoprotection educative and sunscreen (Umozi Max) package designed for PWA in reducing sunburns and skin cancer.

PATIENTS AND METHODS

A multicenter, noncontrolled, before-and-after, interventional study was conducted in PWA > 12 years of age, from February to May, 2019, in Malawi. During the baseline and the follow-up visits (at 8 and 15 weeks), subjects received an educational program designed to PWA and use of Umozi Max. At every visit, photoprotection behavior and knowledge were checked and cutaneous lesions were recorded. Univariate and bivariate analysis were performed.

RESULTS

A total of 210 PWA were analyzed, 50% males, with a mean age of 24.5 (SD 11.29) years. The percentage of people using sun protective clothing increased from 80% to 100% and sunscreen from 81.9% to 99.5%. People avoiding the midday sun increased by 38.9% (P < 0.05). Participants that erroneously applied the sunscreen at night diminished from 40% to 4% (P < 0.001). Absent erythema on the face increased from 40% to 90% (P < 0.05). The percentage of patients with actinic keratoses (AK) on all locations significantly decreased during the study. All the participants preferred Umozi Max to previously used sunscreens. The satisfaction with the program was unanimous.

CONCLUSION

The educational program enhanced the use of all photoprotection measures, improved behaviors, and decreased the incidence of solar erythema and contributed to decreasing the incidence of new AKs.

Daily photoprotection to prevent photoaging

BACKGROUND

Extrinsic skin aging or photoaging was previously thought to be almost exclusively due to solar ultraviolet (UV) radiation. However, recent literature has described other contributing factors and clarification is thus required as to what extent and what type of daily photoprotection is needed to mitigate extrinsic skin aging.

METHODS

We reviewed the existing scientific evidence on daily photoprotection, and specific requirements at the product level, to prevent extrinsic skin aging. We critically reviewed the existing evidence on potential ecological and toxicological risks which might be associated with daily photoprotection.

RESULTS

Evidence shows that broad protection against the entire solar range of UVB, UVA, UVA1, visible light, and short infrared (IRA) is required to prevent extrinsic aging. Other exposome factors, such as air pollution and smoking, also contribute to skin aging. Daily broad-spectrum sunscreen photoprotection should thus contain antioxidant ingredients for additional benefits against UV, IRA, and pollution-induced oxidative stress as well as anti-aging active ingredients to provide clinical benefits against skin aging signs, such as wrinkles and dark spots. Broad-spectrum sunscreen containing pigments, such as iron oxide, may be required for melasma prevention. There is no conclusive clinical evidence that daily sunscreen use is unsafe or that it compromises vitamin D synthesis.

CONCLUSION

Daily use of broad-spectrum sunscreen containing antioxidant and anti-aging active ingredients can effectively reduce extrinsic aging.

Synthesis and evaluation of 1,3,5-triazine derivatives as sunscreens useful to prevent skin cancer

The incidence of skin cancers such as non-melanoma skin cancer and malignant melanoma has increased in the last few years mainly because of chronic exposure to ultraviolet (UV) radiation. Sunscreens protect the skin against harmful UV radiations; however, some limitations of these products justify the discovery of new UV filters. Novel 1,3,5-triazine derivatives (12a-h) obtained by the optimization of prototype resveratrol were synthesized and characterized. All compounds exhibited sun protection factor (SPF) and UVA protection factor (UVAPF) in the range of 3-17 and 3-13, respectively. These values were superior to resveratrol and the UV filter ethylhexyl triazone (EHT) currently available on the market. In addition, all compounds demonstrated in vitro antioxidant activity and thermal stability with the decomposition at temperatures above 236 °C. In conclusion, the novel 1,3,5-triazine derivatives have emerged as new UV filters with antioxidant effect useful to prevent skin cancer.

Facial photoprotection in xeroderma pigmentosum (XP) patients: Validation of a new self-reported questionnaire of adherence

BACKGROUND/PURPOSE

Adherence to photoprotection is the only way to prevent skin cancers and eye disease in xeroderma pigmentosum (XP). No validated self-report questionnaire exists for assessing adherence to photoprotection practices in individuals with XP. We sought to validate a self-reported measure of adherence to face photoprotection in this population.

METHODS

Sixty six XP patients recruited from the patient list of the XP specialist service in London, UK, completed a questionnaire of adherence to specific photoprotection behaviours. We measured objective ultraviolet radiation (UVR) exposure to the face continuously for 21 days with a wristworn UVR electronic dosimeter combined with a daily photoprotection diary. Reliability and convergent validity of the questionnaire were tested in relation to overall UVR exposure, UVR dose to the face, daily photoprotection activities, other self-reported photoprotection practices and clinical ratings of patient's protection.

RESULTS

Internal consistency of the questionnaire was satisfactory. Questionnaire total scores were concordant with objective UVR exposure and UVR dose to the face. However, not all participants who reported good/excellent face photoprotection on the questionnaire recorded high levels of photoprotection in the daily diary. Correlations between the questionnaire and other practices and the clinical rating ranged from small to large in size. There was no correlation between the level of face photoprotection and self-reported avoidance of going outside.

CONCLUSIONS

Our questionnaire was reliable and had good convergent validity with other indicators of photoprotection. This questionnaire could assist clinicians to detect low levels of adherence, and the methodology used to develop validated questionnaires for other photosensitive conditions.

Outdoor testing of the photoprotection provided by a new water-based broad-spectrum SPF50+ sunscreen product: two double-blind, split-face, randomized controlled studies in healthy adults

Purpose

Users often under-apply sunscreens, and one of the main reasons cited for this is the cosmetic formulation of the product. To address this, we developed a water-based sunscreen. The product underwent standard laboratory testing (ISO 24444: 2010) and was determined as sun protection factor (SPF) 50+. However, such laboratory testing does not take into account environmental factors of in-use conditions that could potentially affect sunscreen efficacy, particularly of new cosmetic formulations. We aimed to test this product in conditions more representative of real-life solar exposure, to confirm its reported laboratory efficacy.

Methods

Two double-blind, randomized, controlled, split-face intra-individual studies were conducted during summer months in Barcelona. One study compared the product against an SPF15 control (reference standard P3 of ISO 24444: 2010), while the other compared against an SPF50+ control (another commercially available sunscreen). A technician applied the products before sun exposure: investigational product (IP) to one half of the face and the respective control product to the other. Subjects spent 4–6 hrs outdoors performing quiet activities, and sunscreens were reapplied at 2 hourly intervals. A dermatologist clinically scored facial erythema at baseline and at 24 hrs.

Results

Sixty-five subjects were included in total. In both studies, skin treated with the IP showed no significant increase in clinical erythema scoring at 24 hrs. There were statistically significant differences between the IP and the SPF15, but not between the IP and the SPF50+ control. SPF15 did not protect all subjects against solar-induced erythema.

Conclusion

These outdoor studies confirm the efficacy of this new SPF50+ water-based sunscreen in conditions that closer represent real-life sun exposure.

Challenges in assessing the sunscreen-melanoma association

Whether sunscreen use affects melanoma risk has been widely studied with contradictory results. To answer this question we performed a systematic review of all published studies, accounting for sources of heterogeneity and bias. We searched for original articles investigating the sunscreen-melanoma association in humans to February 28, 2018. We then used random-effects meta-analysis to combine estimates of the association, stratified by study design. Stratified meta-analysis and meta-regression were used to identify sources of heterogeneity. We included 21,069 melanoma cases from 28 studies published 1979-2018: 23 case-control (11 hospital-based, 12 population-based), 1 ecological, 3 cohort and 1 randomised controlled trial (RCT). There was marked heterogeneity across study designs and among case-control studies but adjustment for confounding by sun exposure, sunburns and phenotype systematically moved estimates toward decreased melanoma risk among sunscreen users. Ever- vs. never-use of sunscreen was inversely associated with melanoma in hospital-based case-control studies (adjusted odds ratio (OR) = 0.57, 95%confidence interval (CI) 0.37-0.87, pheterogeneity < 0.001), the ecological study (rate ratio = 0.48, 95%CI 0.35-0.66), and the RCT (hazard ratio (HR) = 0.49, 95%CI 0.24-1.01). It was not associated in population-based case-control studies (OR = 1.17, 95%CI 0.90-1.51, pheterogeneity < 0.001) and was positively associated in the cohort studies (HR = 1.27, 95%CI 1.07-1.51, pheterogeneity = 0.236). The association differed by latitude (pinteraction = 0.042), region (pinteraction = 0.008), adjustment for naevi/freckling (pinteraction = 0.035), and proportion of never-sunscreen-users (pinteraction = 0·012). Evidence from observational studies on sunscreen use and melanoma risk was weak and heterogeneous, consistent with the challenges of controlling for innate confounding by indication. The only RCT showed a protective effect of sunscreen.

Mycosporine-Like Amino Acids for Skin Photoprotection

BACKGROUND

Excessive human exposure to solar ultraviolet radiation (UVR) continues to be a major public health concern, with skin cancer rates increasing year on year. The major protective measure is the use of synthetic UVR filters formulated into sunscreens, but there is a growing concern that some of these chemicals cause damage to delicate marine ecosystems. One alternative is the use of biocompatible mycosporine-like amino acids (MAA), which occur naturally in a wide range of marine species. Their role within nature is mainly thought to be photoprotective. However, their potential for human photoprotection is largely understudied.

OBJECTIVE

To review the role of MAA in nature and assess their potential as natural sunscreens for human skin photoprotection.

METHOD

A literature review of all relevant papers was conducted.

CONCLUSION

MAA are natural photostable compounds that are thought to offer photoprotection to marine species. Initially thought of as protective based on their absorption properties in the solar UVR spectrum, it is clear that MAA are multifunctional photoprotective compounds acting as chemical and biological anti-oxidants. This suggests that MAA may offer a novel eco-friendly approach to human skin photoprotection. Most studies have been carried out in vitro and current data strongly suggest that MAA have potential for development as natural biocompatible sunscreens that protect against a diverse range of solar UVR induced adverse effects on human health.

Two azobenzene derivatives CAB/ACB as reusable sunscreen: UV absorptive capacity and biosafety evaluation

Exposure to UV radiation may cause harmful effects to the skin such as damage, aging and cancer, which can be prevented by using sunscreens. Here, two azobenzene derivatives, 4-cholesterocarbonyl-4'-(N,N,N-triethylaminebutyloxyl bromide) azobenzene (CAB) and 4-cholesterocarbonyl-4'-(N,N-diethylaminebutyloxyl) azobenzene (ACB) were studied as reusable sunscreen candidates. Biocompatibility studies including apoptosis, cytotoxicity and in vivo phototoxicity revealed that the two compounds were rather safe, except ACB, which showed a weak phototoxicity in vitro. Both CAB and ACB have good UV absorption capacity not only in their solution state (dimethylsulfoxide, DMSO) but also in the cosmetic cream state. A commercial sunscreen, avobenzone was decomposed upon UV irradiation and lost its UV protection ability, while that of CAB and ACB could be quickly recovered upon visible light irradiation, implying that they can serve as a new type of reusable sunscreen.

Molecular photoprotection of human keratinocytes in vitro by the naturally occurring mycosporine-like amino acid palythine

Background

Solar ultraviolet radiation (UVR) induces molecular and genetic changes in the skin, which result in skin cancer, photoageing and photosensitivity disorders. The use of sunscreens is advocated to prevent such photodamage; however, most formulations contain organic and inorganic UVR filters that are nonbiodegradable and can damage fragile marine ecosystems. Mycosporine‐like amino acids (MAAs) are natural UVR‐absorbing compounds that have evolved in marine species for protection against chronic UVR exposure in shallow‐water habitats.

Objectives

To determine if palythine, a photostable model MAA, could offer protection against a range of UVR‐induced damage biomarkers that are important in skin cancer and photoageing.

Methods

HaCaT human keratinocytes were used to assess the photoprotective potential of palythine using a number of end points including cell viability, DNA damage (nonspecific, cyclobutane pyrimidine dimers and oxidatively generated damage), gene expression changes (linked to inflammation, photoageing and oxidative stress) and oxidative stress. The antioxidant mechanism was investigated using chemical quenching and Nrf2 pathway activation assays.

Results

Palythine offered statistically significant protection (P < 0·005) against all end points tested even at extremely low concentrations (0·3% w/v). Additionally, palythine was found to be a potent antioxidant, reducing oxidatively generated stress, even when added after exposure.

Conclusions

Palythine is an extremely effective multifunctional photoprotective molecule in vitro that has potential to be developed as a natural and biocompatible alternative to currently approved UVR filters.

What's already known about this topic?

Mycosporine‐like amino acids (MAAs) are photoprotective molecules found in marine organisms but there are few data on their ability to protect skin cells from the adverse effects of solar ultraviolet radiation (UVR).

The European Chemicals Agency (ECHA) is concerned about the potential adverse health and ecotoxic effects of eight of 16 commonly used sunscreen filters in Europe. The Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme has expressed similar concerns.

What does this study add?

Palythine, an MAA extracted from an edible seaweed, affords photoprotection against a wide range of adverse effects in HaCaT keratinocytes exposed to solar simulating and ultraviolet A radiation. Of note is protection against two types of DNA photolesions; cyclobutane pyrimidine dimers and 8‐oxo‐7,8‐dihydroguanine.

Palythine is also a potent antioxidant that offers protection even when added after UVR exposure.

What is the translational message?

MAAs should be considered for development as natural biocompatible sunscreens that may address the concerns of the ECHA and EEAP.

Linked Comment: https://doi.org/10.1111/bjd.16598.

https://goo.gl/Uqv3dl

Diet phytochemicals and cutaneous carcinoma chemoprevention: A review

Cutaneous carcinoma, which has occupied a peculiar place among worldwide populations, is commonly responsible for the considerably increasing morbidity and mortality rates. Currently available medical procedures fail to completely avoid cutaneous carcinoma development or to prevent mortality. Cancer chemoprevention, as an alternative strategy, is being considered to reduce the incidence and burden of cancers through chemical agents. Derived from dietary foods, phytochemicals have become safe and reliable compounds for the chemoprevention of cutaneous carcinoma by relieving multiple pathological processes, including oxidative damage, epigenetic alteration, chronic inflammation, angiogenesis, etc. In this review, we presented comprehensive knowledges, main molecular mechanisms for the initiation and development of cutaneous carcinoma as well as effects of various diet phytochemicals on chemoprevention.

Cutaneous squamous cell carcinoma: an epidemiological review

Cutaneous squamous cell carcinoma (SCC) is a common cancer in white populations and its disease burden is often substantially underestimated. SCC occurs more often in men than women and increases dramatically with age; those affected often develop multiple primaries over time, which increases the burden. The main external cause is solar ultraviolet radiation (UVR), with immunosuppression being the other established risk factor, shown by the high SCC rates in organ transplant recipients. Sunbed use and certain genetic disorders and medical conditions are also associated with SCC, while associations with human papillomavirus infection and high bodyweight are not established. The presence of actinic keratoses (AKs) on sun-damaged skin is one of the strongest predictors of SCC in unaffected people and a very small proportion of AKs are SCC precursors, although the true rate of malignant transformation of AKs is unknown. The mainstay of SCC prevention is protection of the skin from undue sun exposure by use of clothing cover and sunscreen during summer or in sunny places. Educational, behavioural and multicomponent interventions directed at individuals ranging from parents of newborns, to school children and adolescents, to outdoor workers, have repeatedly been shown to be effective in improving sun-protective behaviours. Health policies can facilitate SCC prevention by setting standards for relevant behaviours to reduce UVR exposure, for example, by legislated restriction of the tanning industry. Skin cancer prevention initiatives are generally highly cost-effective and public investment should be encouraged to control the growing public health problems caused by SCC.

An appraisal of the need for infrared radiation protection in sunscreens

Many sunscreens incorporate agents that are said to protect against infrared (IR) damage in the skin but we lack any real data on their benefit in the context of normal human behaviour in the sun. The object of this study was to examine typical IR exposure levels to the sun and industrial sources in order to decide whether there is a need for sunscreens to contain agents that protect against IR radiation, specifically the IR-A waveband. We reviewed claims currently made by products offering protection against IR-A and studies on the biological and clinical effects attributed to IR-A, and compared IR-A exposure levels from these studies with those typically received from the sun and from industrial sources. We found that annual levels of IR-A exposure resulting from typical behaviour in the sun are commensurate with those experienced occupationally by workers exposed to industrial sources of IR, such as steel and glass furnaces. Yet these workers appear to suffer little in the way of chronic skin damage. We conclude that there is not compelling evidence to demonstrate that observable, deleterious cutaneous effects are occurring at doses of solar IR radiation corresponding to those experienced by populations in their normal environments and for this reason we believe it is premature to incorporate IR protection into topical sunscreens and to make claims related to ageing of the skin that consumers may expect to see.

A prospective study of measured body size and height and risk of keratinocyte cancers and melanoma

BACKGROUND

The potential influence of measured body weight and height on keratinocyte skin cancer risk has scarcely been studied. Some evidence indicates melanoma risk increases as self-reported height increases, but an association with body mass index (BMI) is less certain.

METHODS

We measured body weight and height of 1171 Australian men and women in a community-based skin cancer study in Queensland and prospectively examined the association of BMI, body surface area (BSA) and height and incidence of basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and melanoma while accounting for skin phenotype, sun exposure, clinical/cutaneous signs of chronic photodamage and other risk factors.

RESULTS

During 16 years of follow-up, 334 and 188 participants newly developed BCC and SCC, respectively; 28 participants were diagnosed with primary melanoma. BMI and BSA were unrelated to skin cancer incidence. After full adjustment, height was significantly associated with SCC development in men (relative risk (RR)=1.66; 95% confidence interval (CI)=1.11-2.48, for ≥175cm vs ≤171cm, Ptrend=0.017), and BCC in women (Ptrend=0.043). Melanoma in men, was similarly positively associated with height (RR per 5cm increment=1.55; 95%CI 0.97-2.47, P=0.067) though not significantly.

CONCLUSION

This study shows that after adjusting for sun exposure tall stature may be a risk factor for the most common types of skin cancer BCC, SCC, and melanoma, while body mass and surface area appear unrelated to risk.

Assessment of attitudes towards sun-protective behaviour in Australians: A cross-sectional study

OBJECTIVE

To assess the knowledge, attitudes and behaviour towards sun protection measures in a sample of Australian adults.

METHODS

A multicentre, cross-sectional study was undertaken during 2014 using a population-based survey of 416 individuals over the age of 18. The knowledge, behaviour and attitudes towards sun protection measures in this group of adults were assessed. The impact of educational level and employment status on responses was also evaluated.

RESULTS

Sunscreen is the most common sun-protective measure. Daily sunscreen use is below 20%. Forgetfulness was the largest barrier to sunscreen use. A total of 85% of respondents did not apply a sufficient amount of sunscreen. Only 32% of individuals reapplied sunscreen every 2 hours and 20% never reapplied it. In the preceding year, one or more sun burns were suffered by 46% of the participants in the survey. In all, 36% of individuals rarely or never check their sunscreens expiry date and less than 50% of individuals replaced their sunscreen each year. Furthermore, 65% were unaware that sunscreens stored above 25°C were less effective than when stored correctly as per manufactures labelling.

CONCLUSIONS

This study highlights a number of significant deficiencies that future sun-protection programmes could target in order to improve the general public's knowledge and attitudes towards sun protection. There is also a need for this to be translated into the public's sun-protection behaviour.

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.

The relationship between occupational sun exposure and non-melanoma skin cancer: clinical basics, epidemiology, occupational disease evaluation, and prevention

BACKGROUND

The cumulative effect of solar ultraviolet (UV) radiation is responsible for the worldwide increase in non-melanoma skin cancer, a category that includes squamous cell carcinoma and its precursors (the actinic keratoses) as well as basal-cell carcinoma. Non-melanoma skin cancer is the most common type of cancer in areas of the world with a light-skinned population. The occupational exposure to UV radiation is high in many outdoor occupations; recent studies suggest that persons working in such occupations are more likely to develop non-melanoma skin cancer.

METHODS

On the basis of a selective review of the literature, we present the current state of knowledge about occupational and non-occupational UV exposure and the findings of meta-analyses on the association of outdoor activity with non-melanoma skin cancer. We also give an overview of the current recommendations for prevention and for medicolegal assessment.

RESULTS

Recent meta-analyses have consistently documented a significantly higher risk of squamous cell carcinoma of the skin among persons who work outdoors (odds ratio [OR] 1.77, 95% confidence interval [CI] 1.40-2.22, p<0.001). There is also evidence for an elevated risk of basal-cell carcinoma (OR 1.43, 95% CI 1.23-1.66, p = 0.0001), but the effect is of lesser magnitude and the study findings are not as uniform.

CONCLUSION

The association of occupational exposure to solar UV radiation with squamous cell carcinoma, including actinic keratosis, has been conclusively demonstrated. It follows that, in Germany, suspected non-melanoma skin cancer in persons with high occupational exposure to UV radiation should be reported as an occupational disease under § 9, paragraph 2 of the Seventh Book of the German Social Code (Sozialgesetzbuch, SGB VII). Preventive measures are urgently needed for persons with high occupational exposure to UV radiation.

Nonmelanoma skin cancer of the head and neck: prevention

The importance and effectiveness of prevention efforts and strategies for skin cancers are reviewed. Topical sunscreens and their proper use are presented. Topical and ingested forms of natural, synthetic, or biologic chemical agents that are potentially efficacious for chemoprevention are listtdldted and discussed.

Sun-care product advertising in parenting magazines: what information does it provide about sun protection?

This study analyzed the content of sun-care product advertisements in five major U.S. parenting magazines with high circulation: Family Circle, Parents, Family Fun, Parenting (Early Years), and Parenting (School Years). The study examined what information sun-care product advertisements tell parents about skin cancer prevention and about sunscreen use for themselves or for their children based on the Health Belief Model concepts of perceived benefits and perceived barriers. Results showed that the most commonly mentioned benefit of the product was that it blocks ultraviolet A (UVA) and ultraviolet B (UVB) rays. One-third of the ads promoted the product's effectiveness in overcoming four of the barriers that prevent people from using sunscreens: eye irritation, skin irritation, an unpleasant smell, and the need to reapply sunscreen too often or after physical activity. However, only a few of the ads provided information about the consequences of unprotected sun exposure or mentioned methods of sun protection or skin cancer prevention other than sunscreen use. We discuss the implications of these messages for parents' ability to understand correctly how to protect their children from damaging sun exposure.

Enhancing planning strategies for sunscreen use at different stages of change

To promote sun safety by implementing different plans for sunscreen use, different psychological interventions are compared. Self-regulatory strategies such as action planning and coping planning are seen as proximal predictors of actual behavior. The study compares a pure planning intervention with a broader resource communication and examines differential effects at different stages of change. A sun safety online study was designed with two intervention groups (resource communication versus planning) and one control group at two assessment points, 2 weeks apart. Participants (N = 292) were grouped post hoc according to their stage of change, resulting in 51 pre-intenders (no intention to use sunscreen), 102 intenders (high intention but no regular use of sunscreen) and 139 actors (sunscreen use on a regular basis). No overall treatment effects on planning, but an interaction between time, stage and intervention emerged. The resource communication was more effective for pre-intenders, whereas the planning intervention proved more effective for intenders. A planning treatment was more beneficial in motivated individuals, whereas a broader approach was better for unmotivated ones. Findings highlight the potential that stage-matched interventions might have in the context of sun safety promotion.

Knowledge, perceptions and behaviours about skin cancer and sun protection among secondary school students from Central Italy

BACKGROUND

Although sun exposure is a strong risk factor for skin cancer, tanning is very popular among adolescents. Awareness of skin cancer and sun exposure might influence sun protective behaviours in this population.

OBJECTIVES

To investigate the awareness of skin cancer and sun-safe practices among Italian adolescents.

METHODS

A questionnaire about knowledge of skin cancer, perceived severity of sun rays/skin cancer and behaviour toward sun protection was administered to 1204 secondary school students. Predictors of these three components were assessed by case-control analyses considering different combinations of answers. Multiple logistic regression models were used to this scope.

RESULTS

The majority of participants had heard of skin cancer in the past (97.0%), correctly identified possible causes (58.6%) and names (64.2%) of skin cancers and judged appropriately the perceived danger of sunrays (70.2%) and skin cancer (80.6%). Nonetheless, students' behaviour was poor: only 13.5% stated to always use sun-safe practices and 39.1% never used any. Independent predictors of proper knowledge were: Lyceum school, and family or TV/media as information source; of appropriate perceived severity: Lyceum school, a darker skin type, and dermatologists as information source; of acceptable behaviour: female sex, a darker skin type, and dermatologists or general practitioners (GPs) as information source.

CONCLUSIONS

Despite a fairly good knowledge about skin cancer and sun exposure, students' behaviour was unsatisfactory. Knowledge is not sufficient to produce a positive behaviour, as determinants of these two aspects are different. Dermatologists and GPs should be considered as key-figures for future multicomponent intervention strategies in this field.

Prospective study of physical activity and risk of squamous cell carcinoma of the skin

BACKGROUND

The relationship between physical activity and risk of cutaneous squamous cell carcinoma (SCC) is unknown and difficult to investigate due to confounding by sun exposure. We prospectively examined the association of recreational and occupational physical activity and incidence of SCC accounting for photoaging and other risk factors.

METHODS

We used available information on physical activity from the Australian population-based Nambour Skin Cancer Study comprising 1,171 adults aged 25-75 years at baseline (1992). In sex-stratified analyses (person-based and tumor-based) we estimated the associations between type of activity and incidence of SCC prospectively to 2007.

RESULTS

During 16 years of follow-up, 98 men and 90 women newly developed SCC. We found no significant association between recreational activity measures and SCC after controlling for potential confounding factors including indicators of sun exposure. In men, the observed risk pattern was however suggestive of elevated risk with increasing total hours of recreational activity (compared to inactive men, RR (95%CI) 0.89 (0.54, 1.46) for ≤ 1.5 hrs/wk; 1.29 (0.82, 2.04) for ≤ 4.0 hrs/wk; 1.33 (0.86, 2.05) > 4.0 hrs/wk), while among women, higher level of occupational activity (standing and manual versus sedentary work activities) was associated with a reduced incidence of SCC tumors (P trend = 0.03).

CONCLUSIONS

Despite some suggestion that recreational activity in men and occupational activity in women are related to occurrence of SCC, there is no firm support for a role of physical activity in the development of cutaneous SCC.

Melanoma risk in relation to use of sunscreen or other sun protection methods

BACKGROUND

Epidemiologic evidence supporting sunscreen for melanoma prevention is limited to one small trial; case-control studies report conflicting results. Sunscreen usage patterns or alternative sun protection methods have rarely been studied in relation to melanoma.

METHODS

In a population-based case-control study, participants (1,167 cases; 1,101 controls) reported for each decade year of age outdoor activity-related sunscreen use, sunscreen patterns (SPF15+, amount, skin coverage, reapplication, routine use), and use of other sun protection methods (like hats, long-sleeved shirts, staying in the shade). Scores were averaged across activities and/or decades; scores in the most recent two decades were used to classify individuals as non-, inconsistent- or optimal users. Adjusted mean score differences between cases and controls, and ORs and 95% CIs for melanoma among optimal-, inconsistent- versus nonusers were calculated.

RESULTS

Mean scores for sunscreen, sunscreen patterns or other sun protection methods were low, but higher among controls than cases for SPF15+ sunscreen (P = 0.03) and other sun protection methods (P = 0.006). Adjusted ORs for optimal use of sunscreen and most sunscreen patterns were null or relatively weak, except for routine sunscreen (adjusted OR = 0.44, 95% CI: 0.23-0.86). Optimal use of other sun protection methods was inversely associated with melanoma (adjusted OR = 0.59, 95% CI: 0.44-0.78).

CONCLUSIONS

Optimal use of routine sunscreen or other sun protection methods were most strongly associated with decreased melanoma risk; results are limited by the small number of subjects who used sunscreen routinely and lack of specificity regarding other sun protection methods.

IMPACT

Both improving sunscreen practices and encouraging sun avoidance strategies may be important for melanoma prevention.

Hat, shade, long sleeves, or sunscreen? Rethinking US sun protection messages based on their relative effectiveness

BACKGROUND

Sun protection messages in the United States emphasize sunscreen use, although its efficacy in skin cancer prevention remains controversial.

METHODS

We used data from NHANES 2003-2006, restricted to adult whites (n = 3,052) to evaluate how Americans protect themselves from the sun. Participants completed questionnaires on the frequency with which they used sunscreen, wore a hat, long sleeves, or stayed in the shade, in addition to the number of sunburns in the past year.

RESULTS

Although using sunscreen is the most common sun protective behavior (30%), frequent sunscreen use was not associated with fewer sunburns. However, the odds of multiple sunburns were significantly lower in individuals who frequently avoided the sun by seeking shade (OR = 0.70, p < 0.001) or wearing long sleeves (OR = 0.73, p = 0.01).

CONCLUSIONS

Our findings suggest that shade and protective clothing may be more effective than sunscreen, as typically used by Americans.

The human health effects of ozone depletion and interactions with climate change

Depletion of the stratospheric ozone layer has led to increased solar UV-B radiation (280-315 nm) at the surface of the Earth. This change is likely to have had an impact on human exposure to UV-B radiation with consequential detrimental and beneficial effects on health, although behavioural changes in society over the past 60 years or so with regard to sun exposure are of considerable importance. The present report concentrates on information published since our previous report in 2007. The adverse effects of UV radiation are primarily on the eye and the skin. While solar UV radiation is a recognised risk factor for some types of cataract and for pterygium, the evidence is less strong, although increasing, for ocular melanoma, and is equivocal at present for age-related macular degeneration. For the skin, the most common harmful outcome is skin cancer, including melanoma and the non-melanoma skin cancers, basal cell carcinoma and squamous cell carcinoma. The incidence of all three of these tumours has risen significantly over the past five decades, particularly in people with fair skin, and is projected to continue to increase, thus posing a significant world-wide health burden. Overexposure to the sun is the major identified environmental risk factor in skin cancer, in association with various genetic risk factors and immune effects. Suppression of some aspects of immunity follows exposure to UV radiation and the consequences of this modulation for the immune control of infectious diseases, for vaccination and for tumours, are additional concerns. In a common sun allergy (polymorphic light eruption), there is an imbalance in the immune response to UV radiation, resulting in a sun-evoked rash. The major health benefit of exposure to solar UV-B radiation is the production of vitamin D. Vitamin D plays a crucial role in bone metabolism and is also implicated in protection against a wide range of diseases. Although there is some evidence supporting protective effects for a range of internal cancers, this is not yet conclusive, but strongest for colorectal cancer, at present. A role for vitamin D in protection against several autoimmune diseases has been studied, with the most convincing results to date for multiple sclerosis. Vitamin D is starting to be assessed for its protective properties against several infectious and coronary diseases. Current methods for protecting the eye and the skin from the adverse effects of solar UV radiation are evaluated, including seeking shade, wearing protective clothing and sunglasses, and using sunscreens. Newer possibilities are considered such as creams that repair UV-induced DNA damage, and substances applied topically to the skin or eaten in the diet that protect against some of the detrimental effects of sun exposure. It is difficult to provide easily understandable public health messages regarding "safe" sun exposure, so that the positive effects of vitamin D production are balanced against the negative effects of excessive exposure. The international response to ozone depletion has included the development and deployment of replacement technologies and chemicals. To date, limited evidence suggests that substitutes for the ozone-depleting substances do not have significant effects on human health. In addition to stratospheric ozone depletion, climate change is predicted to affect human health, and potential interactions between these two parameters are considered. These include altering the risk of developing skin tumours, infectious diseases and various skin diseases, in addition to altering the efficiency by which pathogenic microorganisms are inactivated in the environment.

Reduced melanoma after regular sunscreen use: randomized trial follow-up

PURPOSE

Regular sunscreen use prevents cutaneous squamous cell carcinoma long term, but the effect on melanoma is highly controversial. We evaluated whether long-term application of sunscreen decreases risk of cutaneous melanoma.

PARTICIPANTS AND METHODS

In 1992, 1,621 randomly selected residents of Nambour, a township in Queensland, Australia, age 25 to 75 years, were randomly assigned to daily or discretionary sunscreen application to head and arms in combination with 30 mg beta carotene or placebo supplements until 1996. Participants were observed until 2006 with questionnaires and/or through pathology laboratories and the cancer registry to ascertain primary melanoma occurrence.

RESULTS

Ten years after trial cessation, 11 new primary melanomas had been identified in the daily sunscreen group, and 22 had been identified in the discretionary group, which represented a reduction of the observed rate in those randomly assigned to daily sunscreen use (hazard ratio [HR], 0.50; 95% CI, 0.24 to 1.02; P = .051). The reduction in invasive melanomas was substantial (n = 3 in active v 11 in control group; HR, 0.27; 95% CI, 0.08 to 0.97) compared with that for preinvasive melanomas (HR, 0.73; 95% CI, 0.29 to 1.81).

CONCLUSION

Melanoma may be preventable by regular sunscreen use in adults.

Sunscreens: expectation and realization

BACKGROUND

The technical performance of sunscreens has improved dramatically over the past 20 years, so have we now succeeded in delivering protection that meets consumers' expectations?

METHODS

From a public health perspective, the desire to prevent sunburn and protect against skin cancer are the two major drivers for using sunscreen. This review examines how well consumers can expect to realize these expectations.

RESULTS

Sunscreens are used regularly by a minority of people, even during recreational summer exposure. The failure of sunscreen to prevent sunburn is almost always due to the way that sunscreens are applied rather than technical failure of the product. The mismatch between the labelled protection (sun protection factor) and that delivered in practice is a contributory factor to this 'failure'. Sunscreens have been shown to be effective in reducing the incidence of squamous cell cancer and with promising benefits for basal cell cancer. However, the evidence that they are effective in melanoma remains lacking.

CONCLUSION

The formulation and extinction of sunscreens have undoubtedly improved over recent years. Yet the notion that sunscreens provide unequivocal protection against the deleterious effects of sun exposure by everyone who uses them remains elusive.