Sunscreen photoprotection and vitamin D status Passeron, T.; Bouillon, R.; Callender, V. ...
British journal of dermatology (1951),
November 2019, 2019-11-00, 20191101, Letnik:
181, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Summary
Background
Global concern about vitamin D deficiency has fuelled debates on photoprotection and the importance of solar exposure to meet vitamin D requirements.
Objectives
To review the ...published evidence to reach a consensus on the influence of photoprotection by sunscreens on vitamin D status, considering other relevant factors.
Methods
An international panel of 13 experts in endocrinology, dermatology, photobiology, epidemiology and biological anthropology reviewed the literature prior to a 1‐day meeting in June 2017, during which the evidence was discussed. Methods of assessment and determining factors of vitamin D status, and public health perspectives were examined and consequences of sun exposure and the effects of photoprotection were assessed.
Results
A serum level of ≥ 50 nmol L−1 25(OH)D is a target for all individuals. Broad‐spectrum sunscreens that prevent erythema are unlikely to compromise vitamin D status in healthy populations. Vitamin D screening should be restricted to those at risk of hypovitaminosis, such as patients with photosensitivity disorders, who require rigorous photoprotection. Screening and supplementation are advised for this group.
Conclusions
Sunscreen use for daily and recreational photoprotection does not compromise vitamin D synthesis, even when applied under optimal conditions.
What's already known about this topic?
Knowledge of the relationship between solar exposure behaviour, sunscreen use and vitamin D is important for public health but there is confusion about optimal vitamin D status and the safest way to achieve this.
Practical recommendations on the potential impact of daily and/or recreational sunscreens on vitamin D status are lacking for healthy people.
What does this study add?
Judicious use of daily broad‐spectrum sunscreens with high ultraviolet (UV) A protection will not compromise vitamin D status in healthy people.
However, photoprotection strategies for patients with photosensitivity disorders that include high sun‐protection factor sunscreens with high UVA protection, along with protective clothing and shade‐seeking behaviour are likely to compromise vitamin D status.
Screening for vitamin D status and supplementation are recommended in patients with photosensitivity disorders.
Linked Comment: Bikle. Br J Dermatol 2019; 181:884.
Plain language summary available online
Frontal fibrosing alopecia (FFA) is a chronic cicatricial alopecia with unknown etiology and a worldwide rising incidence.
The objective of this study was to evaluate the association of FFA with ...demographic and exposure factors in a Brazilian multiracial population.
A multicenter case-control study was conducted in 11 referral centers throughout Brazil. The study was a case-control study that prospectively recruited 902 participants (451 patients with FFA and 451 sex-matched control individuals). Study participants completed a thorough questionnaire comprising variables grouped as baseline demographics, environmental exposure, diet, hormonal factors, allergies, and hair and skin care.
When adjusted by sex, age, menopause, and skin color, FFA was associated with hair straightening with formalin (odds ratio OR, 3.18), use of ordinary (nondermatologic) facial soap (OR, 2.09) and facial moisturizer (OR, 1.99), thyroid disorders (OR, 1.69), and rosacea (OR, 2.08). Smokers (OR, 0.33) and users of antiresidue/clarifying shampoo (OR, 0.35) presented a negative association with FFA. There was no association with the use of sunscreen.
Recall bias.
The association with moisturizers, ordinary facial soap, and hair straightening with formalin and the negative association with antiresidue/clarifying shampoo reinforce the possibility of an exogenous particle triggering FFA.
Summary
Background
Sunscreen use can prevent skin cancer, but there are concerns that it may increase the risk of vitamin D deficiency.
Objectives
We aimed to review the literature to investigate ...associations between sunscreen use and vitamin D3 or 25 hydroxyvitamin D 25(OH)D concentration.
Methods
We systematically reviewed the literature following the Meta‐analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. We identified manuscripts published in English between 1970 and 21 November 2017. Eligible studies were experimental using an artificial ultraviolet radiation (UVR) source, field trials or observational studies. The results of each of the experimental studies and field trials are described in detail. Two authors extracted information from observational studies, and applied quality scoring criteria that were developed specifically for this question. These have been synthesized qualitatively.
Results
We included four experimental studies, three field trials (two were randomized controlled trials) and 69 observational studies. In the experimental studies sunscreen use considerably abrogated the vitamin D3 or 25(OH)D production induced by exposure to artificially generated UVR. The randomized controlled field trials found no effect of daily sunscreen application, but the sunscreens used had moderate protection sun protection factor SPF) ~16. The observational studies mostly found no association or that self‐reported sunscreen use was associated with higher 25(OH)D concentration.
Conclusions
There is little evidence that sunscreen decreases 25(OH)D concentration when used in real‐life settings, suggesting that concerns about vitamin D should not negate skin cancer prevention advice. However, there have been no trials of the high‐SPF sunscreens that are now widely recommended.
What's already known about this topic?
Previous experimental studies suggest that sunscreen can block vitamin D production in the skin but use artificially generated ultraviolet radiation with a spectral output unlike that seen in terrestrial sunlight.
Nonsystematic reviews of observational studies suggest that use in real life does not cause vitamin D deficiency.
What does this study add?
This study systematically reviewed all experimental studies, field trials and observational studies for the first time.
While the experimental studies support the theoretical risk that sunscreen use may affect vitamin D, the weight of evidence from field trials and observational studies suggests that the risk is low.
We highlight the lack of adequate evidence regarding use of the very high sun protection factor sunscreens that are now recommended and widely used.
Linked Editorial: Wolf. Br J Dermatol 2019; 181:881–882.
Plain language summary available online
Minerals such as TiO
2 and ZnO are extensively used in sunscreen lotions as active broadband sunscreens that screen both UVB (290–320
nm) and UVA (320–400
nm) sunlight radiation and as high SPF ...makers, as well as being well-known active semiconductor photocatalysts used extensively to destroy environmental organic pollutants. They have also been shown to induce damage to DNA plasmids in vitro and to whole human skin cells in cultures, thus requiring that they be made photo-inert for use in sunscreens and suncare products that also contain chemical (organic) UV filters (e.g., Padimate-O; see figure), whose photostabilities under simulated sunlight UV radiation in polar and apolar solvents and in actual commercial formulations have been questioned.
Minerals such as titanium dioxide, TiO
2, and zinc oxide, ZnO, are well known active semiconductor photocatalysts used extensively in heterogeneous photocatalysis to destroy environmental pollutants that are organic in nature. They are also extensively used in sunscreen lotions as active broadband sunscreens that screen both UVB (290–320
nm) and UVA (320–400
nm) sunlight radiation and as high SPF makers. When so photoactivated by UV light, however, these two particular metal oxides are known to generate highly oxidizing radicals (
OH and
O
2
-
) and other reactive oxygen species (ROS) such as H
2O
2 and singlet oxygen,
1O
2, which are known to be cytotoxic and/or genotoxic. Hydroxyl (
OH) radicals photogenerated from photoactive TiO
2 specimens extracted from commercial sunscreen lotions R. Dunford, A. Salinaro, L. Cai, N. Serpone, S. Horikoshi, H. Hidaka, J. Knowland, FEBS Lett. 418 (1997) 87 induce damage to DNA plasmids in vitro and to whole human skin cells in cultures. Accordingly, the titanium dioxide particle surface was modified to produce TiO
2 specimens of considerably reduced photoactivity. Deactivation of TiO
2 diminishes considerably, in some cases completely suppresses damage caused to DNA plasmids, to human cells, and to yeast cells compared to non-modified specimens exposed to UVB/UVA simulated solar radiation. The photostabilities of sunscreen organic active agents in neat polar and apolar solvents and in actual commercial formulations have been examined N. Serpone, A. Salinaro, A.V. Emeline, S. Horikoshi, H. Hidaka, J. Zhao, Photochem. Photobiol. Sci. 1 (2002) 970. With rare exceptions, the active ingredients undergo photochemical changes (in some cases form free radicals) and the sunscreen lotions lose considerable Sun protection efficacy only after a relatively short time when exposed to simulated sunlight UVB/UVA radiation, confirming the recent findings by Sayre et al. R.M. Sayre, J.C. Dowdy, A.J. Gerwig, W.J. Shields, R.V. Lloyd, Photochem. Photobiol. 81 (2005) 452.
Effect of sunscreen on vitamin D Neale, R.E.; Khan, S.R.; Lucas, R.M. ...
British journal of dermatology (1951),
November 2019, 2019-11-00, 20191101, Letnik:
181, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Summary
Vitamin D is essential for bone health and is produced by the skin in response to ultraviolet radiation (UVR) from sunlight. UVR is also the main cause of skin cancer, the UK's most common ...type of cancer. Therefore, there have been several concerns that sun protection methods such as using sunscreen can affect vitamin D production.
Researchers from the QIMR Berghofer Medical Research Institute in Australia, and the Australian National University, systematically reviewed for the first time all published experimental studies, field trials, and observational studies published between 1970 and 2017, totalling 75 studies, in order to understand the effect of sunscreen use on vitamin D levels.
The researchers found that while the experimental studies (using artificial light sources in a laboratory setting) support the theoretical risk that sunscreen use may affect vitamin D, the weight of evidence from field trials and observational studies (taking place in real‐life situations involving natural sunlight) suggests that the risk is low.
The researchers explain that the conditions in the experimental studies did not reflect those of the real world, so the results cannot be used to inform practical recommendations for the public.
The authors of this review concluded that there is little evidence that sunscreen, when used in real‐life settings, decreases vitamin D levels and in some cases sunscreen use was associated with higher vitamin D levels. Therefore, concerns about vitamin D levels should not interfere with skin cancer prevention advice. Future trails should consider high sun protection factor sunscreens which are now widely recommended.
Linked Article: Neale et al. Br J Dermatol 2019; 181:907–915
The concept of modern human sun protection is no more than one hundred years, but real development of it, including protection against UVA + UVB radiation (and more recently also the IR and blue ...light), has been no more than 30 years. One fundamental issue while formulating sunscreens is the photostability of the UV filters, which is particularly feeble for the UVA. The gold standard for the determination of sunscreen UVA protection “in vitro” is ISO 24443:2021. Still, interlaboratory results are not as consistent as expected. The Technical Committee for Cosmetics (ISO TC 217) has tried to standardize the method with precise specifications for the materials and equipment used. In particular, the standardization of UV exposure sources based on Xe arc lamps. This fact requires expensive equipment out of the reach of many laboratories to achieve adequate temperature control on the samples. In this paper, it will be shown that, within the experimental error, satisfactory results were achieved with a cheap commercial LED source irradiating only in the UVA spectra. Evidence is presented to conclude that other more relevant factors must be considered as the main cause of uncertainties.
While formulating sunscreens, the photostability of the UV filters, especially in the UVA range, is fundamental. Interlaboratory results are not as consistent as expected for determining Sunscreen UVA Protection “in vitro”. The ISO Technical Committee for Cosmetics has standardized a precise methodology. In particular, the standardization of UV exposure sources based on Xe arc lamps. This fact requires expensive equipment, that is unaffordable for many laboratories. It will be shown that satisfactory results could be achieved with a commercial LED source, irradiating only in the UVA spectra. Other more relevant factors must be considered as the main cause of uncertainties.
Summary
Background
Sunlight contains ultraviolet (UV)A and UVB radiation. UVB is essential for vitamin D synthesis but is the main cause of sunburn and skin cancer. Sunscreen use is advocated to ...reduce the sun's adverse effects but may compromise vitamin D status.
Objectives
To assess the ability of two intervention sunscreens to inhibit vitamin D synthesis during a week‐long sun holiday.
Methods
The impact of sunscreens on vitamin D status was studied during a 1‐week sun holiday in Tenerife (28° N). Comparisons were made between two formulations, each with a sun protection factor (SPF) of 15. The UVA‐protection factor (PF) was low in one case and high in the other. Healthy Polish volunteers (n = 20 per group) were given the sunscreens and advised on the correct application. Comparisons were also made with discretionary sunscreen use (n = 22) and nonholiday groups (51·8° N, n = 17). Sunscreen use in the intervention groups was measured. Behaviour, UV radiation exposure, clothing cover and sunburn were monitored. Serum 25‐hydroxyvitamin D3 25(OH)D3 was assessed by high‐performance liquid chromatography–tandem mass spectrometry.
Results
Use of intervention sunscreens was the same (P = 0·60), and both equally inhibited sunburn, which was present in the discretionary use group. There was an increase (P < 0·001) in mean ± SD 25(OH)D3 (28·0 ± 16·5 nmol L−1) in the discretionary use group. The high and low UVA‐PF sunscreen groups showed statistically significant increases (P < 0·001) of 19·0 ± 14·2 and 13·0 ± 11·4 nmol L−1 25(OH)D3, respectively with P = 0·022 for difference between the intervention sunscreens. The nonholiday group showed a fall (P = 0·08) of 2·5 ± 5·6 nmol L−1 25(OH)D3.
Conclusions
Sunscreens may be used to prevent sunburn yet allow vitamin D synthesis. A high UVA‐PF sunscreen enables significantly higher vitamin D synthesis than a low UVA‐PF sunscreen because the former, by default, transmits more UVB than the latter.
What's already known about this topic?
Action spectra (wavelength dependence) for erythema and the cutaneous formation of vitamin D overlap considerably in the ultraviolet (UV)B region.
Theoretically, sunscreens that inhibit erythema should also inhibit vitamin D synthesis.
To date, studies on the inhibitory effects of sunscreens on vitamin D synthesis have given conflicting results, possibly, in part, because people typically apply sunscreen suboptimally.
Many studies have design flaws.
What does this study add?
Sunscreens (sun protection factor, SPF 15) applied at sufficient thickness to inhibit sunburn during a week‐long holiday with a very high UV index still allow a highly significant improvement of serum 25‐hydroxyvitamin D3 concentration.
An SPF 15 formulation with high UVA protection enables better vitamin D synthesis than a low UVA protection product. The former allows more UVB transmission.
Linked Editorial: Wolf. Br J Dermatol 2019; 181:881–882.
Plain language summary available online
Respond to this article
Background
The recommended amount of sunscreen by hand application (2 mg/cm2) is in reality not achieved, which decreases the homogeneity and thereby the effective sun protection factor (SPF).
...Materials and Methods
The homogeneity of sunscreen applied by a newly developed spray applicator using an electrostatically charged aerosol, for which a hand rubbing of the formulation is not necessary, is evaluated. In vivo experiments were performed on the volar forearms of human volunteers using the spray applicator compared to the standardized hand application according to ISO 24444.
Results
The distribution homogeneity was assessed qualitatively using in vivo laser scanning microscopy and quantitatively by absorption spectroscopy after tape stripping and by the standard deviation of multiple spatially displaced reflectance measurements for non‐invasive SPF determination below the minimal erythemal dose, which showed a significantly higher homogeneity by 20.9% after spray application compared to hand application.
Conclusion
Non‐invasive SPF determination of multiple spatially displaced reflectance measurements was proven to be a suitable method for the non‐invasive determination of the sunscreen distribution homogeneity. Electrostatically charged spray application increased the sunscreen distribution homogeneity on the skin and can reduce the amount of overspray.
Availability of new UV filters in the United States lags behind the European Union (EU), partly due to differing approval processes.
To review available human safety data of all US- and EU-approved ...UV filters.
Data from Food and Drug Administration and EU regulatory guidelines, federal governmental documentation, databases, reviews, and opinions for approval and ongoing safety evaluation were analyzed.
Currently, there are 17 US UV filters and 29 EU UV filters (18 EU-approved only filters). Almost all US filters possessed sensitization data (94%, 16/17) with the majority (76%, 13/17) showing minimal skin sensitization. The minority of EU-approved only filters (33%, 6/18) possessed sensitization data, all showing no sensitization. Some filters possessed dermal absorption data (US: 76%, 13/17; EU: 44%, 8/18). Oxybenzone, octinoxate, octisalate, homosalate, and octocrylene, approved in the US and EU, were shown to have plasma levels exceeding the Food and Drug Administration exposure threshold.
Proprietary manufacturer human data were unavailable.
Many new UV filters are available in the EU, but not yet in the United States. Rigorous US and EU guidelines ensure that UV filters provide adequate photoprotection assuming consumers follow American Academy of Dermatology SPF (sun protection factor) and broad-spectrum recommendations. Human data are limited, but known human risks of sunscreen appear minimal.
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