Perspectives on the FDA’s Sunscreen Policy: New Aging Theory, Sunlight Benefits, Enhanced Immunity, COVID-19 Mortality, Modelling Analyses, Melanoma Risks and Etiology

Abstract

Currently, the U.S. Food and Drug Administration's policy on sunscreens assumes that exposure to sunlight, mainly ultraviolet (UV) rays, damages the skin, the damage is cumulative and any sun exposure should be avoided or minimized. Sunscreens are approved to help prevent early skin aging, sunburn and skin cancer. This work presents provocative perspectives on some issues related to use of sunscreens shown below. Skin aging is predominantly caused by the intrinsic nutritional factor. Sunlight damage is unlikely cumulative due to extremely efficient self-repair/self-defense mechanisms of the body. Regular exposure to moderate nonburning sunlight increases immunity and protects against sunburn, melanoma, COVID-19 mortality, high blood pressure, etc. White and non-white populations may need sun protection only when the UV Index is ≥ 5-6 and ≥ 7-8, respectively. Modelling analyses suggest that sunscreens with SPF 8 and 2-6 may be adequate for whites and non-whites, respectively. There are inherent risks of sunburn and melanoma when sunscreen is used intermittently mainly due to unavoidable SPF-independent missing applications and may serve as a false security; this may mainly account for exponential increases in melanoma incidences in recent decades; thus, the more intermittent use of sunscreen, the more incidence of sunburn and skin cancer. 10am-2pm sunlight avoidance guidelines may need modification. Extensive human studies suggest that intense UVB from sunburn, not UVA or sub-erythemal UVB, may cause melanoma; this hypothesis is supported by mouse and fish models. Without exposure to burning sunlight, we

Severe Sunburn as the Overwhelming Risk Factor for 3 Common Skin Cancers: New Prevention Strategy

“…Interestingly, it was reported by Petersen, et al, that "A sun holiday is a sunburn holiday" for all 25 people who used sunscreen with an SPF of 30 and developed unintended sunburn after spending one week of sunbathing at a subtropical resort [7]. Therefore, the present work also suggests sunscreen use for intense intermittent sun exposure as a potential major risk factor for skin cancer that may primarily or at least partly account for the reported exponential increase of incidences of melanoma and BCC and SCC in the United States and other countries with a temperate climate in the last two or three decades [3,6,8,9]. It is recommended that the potential unintended or unexpected risk of sunburn and skin cancer when using sunscreen for intense intermittent sun exposure be urgently conveyed to the general public as an effort to help prevent SS and skin cancer.…”

“…Obviously, a prudent method is to have direct sun exposure in non-peak hours such as after 3 or 4 p.m. or when sun exposure is nonburning. Use of sunscreen during intermittent exposure can result in unintended sunburns due to factors such as prolonged use and virtually unavoidable SPF-and-site-independent missing applications (even on 1% of the intended area) [3,6]. The resulting unintended or unexpected sunburn may be regarded as a false security phenomenon.…”

“…The present work suggests that erythema may play a less important role in cancer development than commonly assumed. Although erythema can cause damage to DNA, its visible inflammatory sign on the skin can usually disappear with minimum intervention in days [3]. Also, virtually all damaged DNAs may be completely repaired or eliminated by our body's extremely efficient repair mechanisms in weeks or months [3,6,10].…”

“…Although erythema can cause damage to DNA, its visible inflammatory sign on the skin can usually disappear with minimum intervention in days [3]. Also, virtually all damaged DNAs may be completely repaired or eliminated by our body's extremely efficient repair mechanisms in weeks or months [3,6,10]. Based on the BCC data one nay estimate theoretically that only up to 22% of the total BCC cases having ≥ 16 SS could eventually develop melanoma reflecting the body's super ability to defend against cancer development from damaged DNAs.…”

“…2) in contributing to incidences of the three most common skin cancers, namely, melanoma, Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC) appear limited to date. Furthermore, there is a different degree of sunburn ranging from mild sunburn showing only skin reddening or inflammation (i. e., erythema) to Severe Sunburn (SS) with pain, swelling, peeling and/or blistering; conceivably different degrees of sunburn may have different impacts on cancer development [3]. Delineation of the above scenarios may be useful to the design of an effective strategy to prevent skin cancer.…”