Current insights and future perspectives of ultraviolet radiation (UV) exposure: Friends and foes to the skin and beyond the skin

Ultraviolet (UV) radiation is ubiquitous in the environment, which has been classified as an established human carcinogen. As the largest and outermost organ of the body, direct exposure of skin to sunlight or UV radiation can result in sunburn, inflammation, photo-immunosuppression, photoaging and even skin cancers. To date, there are tactics to protect the skin by preventing UV radiation and reducing the amount of UV radiation to the skin. Nevertheless, deciphering the essential regulatory mechanisms may pave the way for therapeutic interventions against UV-induced skin disorders. Additionally, UV light is considered beneficial for specific skin-related conditions in medical UV therapy. Recent evidence indicates that the biological effects of UV exposure extend beyond the skin and include the treatment of inflammatory diseases, solid tumors and certain abnormal behaviors. This review mainly focuses on the effects of UV on the skin. Moreover, novel findings of the biological effects of UV in other organs and systems are also summarized. Nevertheless, the mechanisms through which UV affects the human organism remain to be fully elucidated to achieve a more comprehensive understanding of its biological effects.

Causal associations between modifiable risk factors and isolated REM sleep behavior disorder: a mendelian randomization study

Objectives

This Mendelian randomization (MR) study identified modifiable risk factors for isolated rapid eye movement sleep behavior disorder (iRBD).

Methods

Genome-wide association study (GWAS) datasets for 29 modifiable risk factors for iRBD in discovery and replication stages were used. GWAS data for iRBD cases were obtained from the International RBD Study Group. The inverse variance weighted (IVW) method was primarily employed to explore causality, with supplementary analyses used to verify the robustness of IVW findings. Co-localization analysis further substantiated causal associations identified via MR. Genetic correlations between mental illness and iRBD were identified using trait covariance, linkage disequilibrium score regression, and co-localization analyses.

Results

Our study revealed causal associations between sun exposure-related factors and iRBD. Utilizing sun protection (odds ratio [OR] = 0.31 [0.14, 0.69], p = 0.004), ease of sunburn (OR = 0.70 [0.57, 0.87], p = 0.001), childhood sunburn occasions (OR = 0.58 [0.39, 0.87], p = 0.008), and phototoxic dermatitis (OR = 0.78 [0.66, 0.92], p = 0.003) decreased iRBD risk. Conversely, a deep skin color increased risk (OR = 1.42 [1.04, 1.93], p = 0.026). Smoking, alcohol consumption, low education levels, and mental illness were not risk factors for iRBD. Anxiety disorders and iRBD were genetically correlated.

Conclusion

Our study does not corroborate previous findings that identified smoking, alcohol use, low education, and mental illness as risk factors for iRBD. Moreover, we found that excessive sun exposure elevates iRBD risk. These findings offer new insights for screening high-risk populations and devising preventive measures.

Evaluating the effect of childhood sunburn on the risk of cutaneous melanoma through Mendelian randomization

Despite numerous observational studies indicating an increased risk of cutaneous melanoma (CM) due to childhood sunburn, no studies have established a definitive cause-and-effect relationship. Therefore, our objective was to employ a Mendelian randomization (MR) design to explore a possible causal association between childhood sunburn and the risk of CM. To investigate the causal relationship between childhood sunburn and CM, we used large-scale genetic summary-level data from genome-wide association studies (GWAS), including childhood sunburn (n = 346,955) and CM (n = 262,288), building upon previous observational studies. In the analysis, we mainly used the inverse-variance weighted (IVW) method of the random effects model, supplemented by the weighted median method and MR-Egger method. The results of the IVW method demonstrated that genetically predicted childhood sunburn was significantly associated with higher odds of CM, with an odds ratio (OR) of 2.418 (95%CI, 1.426-4.099; p = .001). The weighted median method and MR-Egger regression also demonstrated directionally similar results (both p < .05). Furthermore, both the funnel plot and the MR-Egger intercepts showed the absence of directional pleiotropy between childhood sunburn and CM. Our study offers potential evidence linking genetically predicted childhood sunburn with CM, underscoring the need for individuals with a history of childhood sunburn to be extra vigilant regarding the occurrence of CM.

Educational level-dependent melanoma awareness in a high-risk population in Switzerland

Introduction

The worldwide incidence of melanoma has been increasing rapidly in recent decades with Switzerland having one of the highest rates in Europe. Ultraviolet (UV) radiation is one of the main risk factors for skin cancer. Our objective was to investigate UV protective behavior and melanoma awareness in a high-risk cohort for melanoma.

Methods

In this prospective monocentric study, we assessed general melanoma awareness and UV protection habits in at-risk patients (≥100 nevi, ≥5 dysplastic nevi, known CDKN2A mutation, and/or positive family history) and melanoma patients using questionnaires.

Results

Between 01/2021 and 03/ 2022, a total of 269 patients (53.5% at-risk patients, 46.5% melanoma patients) were included. We observed a significant trend toward using a higher sun protection factor (SPF) in melanoma patients compared with at-risk patients (SPF 50+: 48% [n=60] vs. 26% [n=37]; p=0.0016). Those with a college or university degree used a high SPF significantly more often than patients with lower education levels (p=0.0007). However, higher educational levels correlated with increased annual sun exposure (p=0.041). Neither a positive family history for melanoma, nor gender or Fitzpatrick skin type influenced sun protection behavior. An age of ≥ 50 years presented as a significant risk factor for melanoma development with an odd's ratio of 2.32. Study participation resulted in improved sun protection behavior with 51% reporting more frequent sunscreen use after study inclusion.

Discussion

UV protection remains a critical factor in melanoma prevention. We suggest that melanoma awareness should continue to be raised through public skin cancer prevention campaigns with a particular focus on individuals with low levels of education.

Knowledge and Attitudes of Cypriots on Melanoma Prevention: Is there a Public Health Concern?

Background

Melanoma is the deadliest type of skin cancer. It is the eighth most common cancer in males and the tenth in females in Cyprus, an island in the Mediterranean with a high ultraviolet (UV) index. Cyprus is expected to be strongly affected by climate change and consequently, melanoma will likely become an increasing public health problem. Melanoma prevention is possible; however, it is unknown if people living in Cyprus are aware of melanoma and prevention methods. To this end, we used a validated survey to evaluate the level of melanoma knowledge and factors associated with it in the Cypriot population.

Methods

We conducted a 47-item survey with sections on demographics, knowledge of melanoma and risk factors, attitudes toward relevant health practices, and protective behaviors among six hundred Cypriot residents from October 2015 to April 2016.

Results

Our results revealed that only 59% of participants check their skin for moles, 87% protect their skin from the sun during summer holidays, and 57% do not take measures to protect their skin from the sun during non-holiday periods. Protective behavior was positively associated with educational level (P=0.016) and district of residence (P<0.0001). Melanoma knowledge was positively associated with education level (P=0.002) and district of residence (P=0.004). Level of Concern was positively associated with age (P=0.026) and education level (P=0.041).

Conclusions

There are gaps in melanoma knowledge and prevention practices in the study population. Further education on melanoma and its prevention should be specifically targeted to individuals of lower education levels as well as teenagers, such that protective behaviors for melanoma are adopted early in life.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12324-0.

Difference in Sun Exposure Habits Between Individuals with High and Low Risk of Skin Cancer

Background

Skin cancer incidence is rapidly increasing. The main risk factor, sun exposure, can be modified. Informational campaigns can be effective in raising skin cancer awareness and target the high-risk population. Still, sun exposure habits in people at high risk of skin cancer are not well-known.

Objective

To investigate if and how sun exposure habits differ between low-risk and high-risk individuals.

Methods

During the Swedish Euromelanoma campaign of 2018, questionnaires were collected containing information regarding sun exposure habits and risk factors for skin cancer. Data on 4,141 participants was used to investigate the association between risk factors and sun exposure habits.

Results

A fair skin type and a previous history of skin cancer were significantly associated with enhanced sun protective behavior. Family history of skin cancer, childhood sunburns and the presence of large/atypical nevi had no effect on sun exposure habits. Going on sunny holidays were particularly unaffected by being at high risk of skin cancer.

Conclusion

Individuals at high risk of developing skin cancer showed suboptimal sun exposure habits and harmful traveling behaviors. We suggest that future skin cancer campaigns inform on accurate sun protection behavior during sunny holidays and associated risk factors. Risk factors such as childhood sunburns, numerous common and large/atypical nevi, as well as family history of skin cancer seem to be less recognized by the population.

Awareness of cancer risk factors and protective factors among Australian adults

ISSUE ADDRESSED

Up to one-third of incident cancers in Australia are attributable to modifiable factors. Understanding the general public's awareness of cancer risk and protective factors is important for identifying knowledge gaps and informing the development of effective and targeted health promotion strategies.

METHODS

In a telephonic survey of 355 Western Australian adults aged 18-54 years (48% male), with a sample skewed towards low-socio-economic status areas, respondents rated the effect on cancer risk of 11 established cancer risk factors and seven established cancer protective factors.

RESULTS

Most respondents correctly recognised the increased cancer risk from sun tanning (94%), asbestos (92%), pesticide use (92%) and being overweight or obese (86%), and the protective effect of being physically active (82%). Half (52%) of respondents incorrectly believed that red wine decreased or had no effect on cancer risk. One in five respondents (19%) incorrectly believed that sunscreen use increased cancer risk. Only 18% of respondents were aware that human papillomavirus (HPV) vaccination confers a protective effect, while 17% believed it increases risk.

CONCLUSIONS

Although the majority of respondents were aware of certain established cancer risk and protective factors, a sizeable proportion held misconceptions about the cancer risk associated with red wine consumption, sunscreen use and HPV vaccination. SO WHAT?: Health promotion programs designed to educate the public about modifiable cancer risk factors may need to increase public awareness of the safety of preventive factors such as HPV vaccination and sunscreen, and the increased cancer risk from consumption of all alcoholic beverage types, including red wine.