Daily photoprotection: What does it really mean?

Journal of Dermatology Research, 2022

Currently the FDA adopts a zero-tolerance policy toward sun exposure in order to prevent skin cancer and premature skin aging (photoaging). This is apparently based on classical concept that damage from sunlight, a carcinogen, is cumulative and un-reparable. Such concept is apparently flawed both theoretically and in reality. The nature’s design to achieve genomic stability of body health and appearance for smooth passage of generations in our normal daily lives would require virtually complete repair of damages of DNA and other tissue components from daily Exposure to Non-Burning Sunlight (ENS). In other words, ENS is generally not expected to cause skin cancer and photoaging. Such notion is evidenced by, for example, low worldwide skin-cancer incidences, severe sunburn as overwhelming skin-cancer etiology, and intrinsic aging as overwhelming skin aging. Since ENS can provide numerous health benefits, such exposure can be regarded as healthy sun exposure and used to help prevent skin cancer. Due to unintended sunburn effect, use of sunscreens for intense intermittent exposure is strongly discouraged. As photoaging and skin cancer may be closely related, some questions related to conventional theories and practices in photoaging are also raised. They include the following: Schuster’s pioneering study in 1975; invalidation of accelerated aging theory; questionable theory on etiology of wrinkles and age spots; Fisher’s studies on metalloproteinases; bolus doing vs constant-rate dosing in irradiation; moisturizers as anti-photoaging/anti-cancer agents; inclusion of blood and water in skin-aging exosome; wind effect; differences in usage pattern between countries in sunscreen evaluation; replacement of UVA in tanning beds.

Journal Der Deutschen Dermatologischen Gesellschaft, 2007

Collegium antropologicum

Chronic sun exposure causes degenerative changes in the skin that are recognized as photoaging, immunosuppression and photocarcinogenesis. Sun is necessary for life, so total sun avoidance is impossible. Sun exposure during the first 15 years of life and blistering sunburns before age 20 have been linked to an increased risk of melanoma. Individuals who have outdoor lifestyles, live in sunny climates, and are lightly pigmented will experience the greatest degree of photoaging. In our study, performed four years ago, we have shown the knowledge of more than 4000 people about the effects of UV rays on the skin. The results show us that sun exposure is still exaggerated and uncontrolled due to the lack of knowledge about this topic. Encouraging photoprotection and improving the awareness of the general public about the harmful effects of too much sun exposure must be the leading preventative health strategy.

Journal of the European Academy of Dermatology and Venereology, 2010

Background We have previously shown the detrimental effects of 19 sub-erythemal exposures to daily ultraviolet radiation (DUVR, which mimics non-extreme exposure conditions), delivered over 4 weeks to volunteers. This source had UVA (320-400 nm) to UVB (290-320 nm) irradiance ratio of 25, instead of that close to 10 that is typically the case with solar-simulated radiation (SSR) that represents summer global sunlight with a clear sky and quasi-zenith solar irradiance. Objective Here, we report on an extension of this previous study, in which we evaluated the photoprotection afforded by a broad-spectrum daily-care product with a low-sun protection factor (SPF 8, UVA-PF 7 and 3* rated UVA protection). We assessed cellular and molecular markers of photodamage that are relevant to skin cancer and photoageing. Results This study shows that biological effects of repeated exposure to DUVR can be prevented by a broad-spectrum daily-care product and that the level of protection afforded varies with the studied endpoint. Conclusion Efficient daily UVR protection, as provided by a broad-spectrum daily-care product, is necessary to prevent the 'silent' sub-erythemal cumulative effects of UVR from inadvertent sun exposure.

British Journal of Dermatology, 1990

The most reliable way to reduce the chronic effects of solar UV radiation is to limit exposure. Animal data using hairless albino mice suggest that the routine use of sunscreens, which usually act as UVB (280-315 nm) filters, may prevent or inhibit skin photocarcinogenesis and photoageing in man. Conditions of chronic use of sunscreens in human skin, however, are not established but it is possible that, under some circumstances, sunscreen use could enhance skin cancer risk. The use of sunscreens may prevent or inhibit both sun-induced cancers and photoageing, but as yet there is no established method of designating the efficacies of sunscreens for the prevention of the chronic effects of solar UV radiation. This is an important research objective. Sunscreens are usually formulated and assessed for the prevention of the acute effects of solar UV radiation (SUR). The efficacy of such preparations in preventing erythema is indicated by their sun protection factor (SPF) and their active agents are usually UVB-(280-315 nm) absorbing molecules. Effective preparations with SPFs of 20 or more are now available, and the public is generally well informed about their use. The chronic effects of SUR, such as skin cancer'-^ and accelerated ageing of the skin (photoageing),^''^ are now well established. Recently, concern has been expressed that possible depletion of the ozone layer may accelerate the already increasing incidence of skin cancer in susceptible populations.' The chronic effects of SUR are often associated with skin senescence, but are quite distinct processes which are, in theory at least, avoidable. It is often stated that regular use of sunscreens would prevent these long-term effects but in reality the precise ability of sunscreens to inhibit these effects in human skin is not known and would be very difficult to determine. PHOTOCARCINOGENESIS Hairless albino mice are widely used as a model for the long-term effects of UV radiation. These animals, with a 2-year lifespan, permit the study of experimentally induced phototumor-'

Dermatology Practical & Conceptual, 2019

Excessive solar exposure presents well-recognized risks and side effects, solar radiation being the most important environmental factor concerning skin cancer. In the last few years, several connections between solar exposure and prevention and/or treatment of several diseases have been discussed, with studies suggesting that regular solar exposure may be beneficial for conditions such as colorectal, breast, prostate, and pancreatic cancer; non-Hodgkin lymphoma; arterial hypertension; obesity; type 2 diabetes mellitus and metabolic syndrome; nonalcoholic hepatic steatosis; multiple sclerosis; Alzheimer disease; and several psychiatric disturbances. In most cases, UV radiation’s beneficial effects are mediated through vitamin D; however, studies show that in other instances other mediators are responsible for these associations, specifically nitric oxide. Moderation is therefore essential, as a strict strategy of total sun avoidance may be inadequate.

Photodermatology, Photoimmunology and Photomedicine, 2000

Background: There is overwhelming evidence that exposure of human skin to ultraviolet radiations (UVR) leads to the development of cutaneous photoaging and eventually to neoplasia. This study was designed to evaluate in humans the protection afforded by a daily use cream containing a photostable combination of UVB and UVA absorbers (Uvinul A N539, Parsol A 1789 and Mexoryl A SX) providing a continuous absorption through the entire UV spectrum, against damages induced by repeated daily exposure to solar simulated radiation (SSR). Methods: Buttock skin of 12 healthy volunteers was exposed 5 days per week for 6 weeks to one minimal erythema dose of solar simulated radiation per exposure. The following parameters in treated and untreated skin were evaluated: erythema, pigmentation, skin hydration, skin microtopography, histology and immunochemistry, and collagen and metalloproteinase (MMP) mRNA levels. Results: In SSR exposed unprotected skin sites, we observed melanization and changes in the skin hy-T he aging process of the skin encompasses two clinically and biologically independent processes that occur simultaneously: chronological or intrinsic aging, which affects skin by slow and irreversible tissue degeneration, and extrinsic aging or photoaging, which results from exposure to environmental factors including primarily ultraviolet radiations (UVR). In areas exposed to sun, skin damages resulting from photoaging are superimposed on tissue degeneration resulting from chronological aging. Chronological aging alone, as seen in sun-protected

Elite Journal of Medical Sciences, 2024

A considerable high number of outdoor workers worldwide are constantly exposed for majority of their working life to sun radiation (SR); this exposure is known to induce various adverse health effects, mainly related to its ultraviolet (UV) component. The skin is one of the principal target organs for both acute and long-term exposure as well as other organs of the body. Ultraviolet B (UVB) rays vary with time and season and are the major cause of sunburns. Sunburned skin is a leading risk factor for melanoma and non-melanoma skin cancers, protection against exposure to UVB rays may be achieved by a combination of various approaches such as use of broad-spectrum sunscreen formulations. There was no significant association between age and color of skin (X 2 =36.929, P=0.005). Researchers recommend using sunscreen to protect the skin from harmful UVR. SR exposure is influenced by various environmental and individual factors, and occupation is one of the most relevant.

Journal of the European Academy of Dermatology and Venereology

Objective There is accumulating evidence that in spite of the large campaigns against excessive solar exposure undertaken by dermatologists worldwide, children and adolescents are still spending long periods in the sun, and do not follow the recommended sun protection guidelines.The purpose of the present study was to evaluate sun exposure in a group of young Israeli adults and to compare it to their knowledge and application of the various sun protection methods.Methods 202 Caucasian volunteers, (mean age 21.4 ± 2.6), filled out detailed questionnaires on their sun exposure and sun protection habits.Results More than 80% of our study participants are regularly sun exposed for longer than 2 h per day whereas sunscreens are utilized only by 64.9%. Sunscreen use was significantly more prevalent in females than males (81.3% vs. 46.5%). The majority of sunscreen users and nonusers believed that sunscreen could prevent skin cancer (94.3% and 82.0%, respectively) and that these compounds ...

Photodermatology, Photoimmunology and Photomedicine, 2006

Background: The irradiance of standard ultraviolet daylight (UV-DL) is representative of most frequently encountered UV exposure conditions and simulators of UV-DL can now be used to properly investigate the biological effects of a non-extreme UV radiation. One of the characteristics of the simulated UV-DL used in this study is its dUVA to dUVB irradiance ratio, which amounts to 24, instead of close to 10, for the simulated zenithal UV radiation (UV-SSR). Purpose/Methods: The aim of our study was to compare photobiological effects induced, in human skin, by acute and semi-chronic exposure to simulated UV-DL with those induced by UV-SSR. Results: Differences between UV doses needed to induce given biological effects after exposure to simulated UV-DL compared with UV-SSR indicate that the spectral distribution of the UV spectrum is of primary importance with regard to biological endpoints in the epidermis (SBC, p53, thymine dimers, Langerhans cells, and melanocyte alterations, etc.) and in the dermis (collagen, tenascin, etc.). Significant biological damage was noticed after 19 cumulative exposures to 0.5 minimum erythemal dose (MED) of UV-DL over 4 weeks. 0.5 MED of UV-DL corresponds to 1/9 of the daily typical dose received in Paris in April, emphasizing the need for an efficient daily UV protection. Conclusion: Simulated UV daylight is a relevant new tool for daily photoprotection studies.