Assessment of spatiotemporal variability of ultraviolet index (UVI) over Kerala, India, using satellite remote sensing (OMI/AURA) data.

The spatial and temporal dynamics of daily ultraviolet index (UVI) for a period of 18 years (2004-2022) over the Indian state of Kerala were statistically characterised in the study. The UVI measurements used for the study were derived from the ultraviolet-B (UVB) irradiance measured by the Ozone Monitoring Instrument (OMI) of the AURA satellite and classified into different severity levels for analysis. Basic statistics of daily, monthly and seasonal UVI as well as Mann-Kendall (MK) statistical trend characteristics and the rate of change of daily UVI using Theil-Sen's slope test were also evaluated. A higher variability of UVI characteristics was observed in the Kerala region, and more than 79% of the measurements fell into the categories of very high and extreme UVI values, which suggests the need of implementation of appropriate measures to reduce health risks. Although the UVI measured during the study period shows a slight decrease, most of the data show a seasonal variation with undulating low and peak values. Higher UVI are observed during the months of March, April and September. The region also has higher UVI during the southwest monsoon (SWM) and summer seasons. Although Kerala region as a single whole unit, UVI show a non-significant decreasing trend (-0.83), the MK test revealed the increasing and decreasing trends of UVI ranging from -1.96 to 0.41 facilitated the delineation of areas (domains) where UVI are increasing or decreasing. The domain of UVI increase occupies the central and southern (S) parts, and the domains of decrease cover the northern (N) and S parts of the Kerala region. The rate of change of daily UVI in domain of increase and decrease shows an average rate of 0.34 × 10-5 day-1 and -2 × 10-5 day-1, respectively. The parameters (rainfall, air temperature, cloud optical depth (COD) and solar zenith angle (SZA)) that affect the strength of UV rays reaching the surface indicate that a cloud-free atmosphere or low thickness clouds prevails in the Kerala region. Overall, the study results indicate the need for regular monitoring of UVI in the study area and also suggest appropriate campaigns to disseminate information and precautions for prolonged UVI exposure to reduce the adverse health effects, since the study area has a high population density.

Pediatric Melanoma: Geographic Trends in Incidence, Stage, and Mortality in the United States.

INTRODUCTION: Pediatric melanoma is the most commonly diagnosed skin cancer in children, with the annual incidence recently increasing by an average of 2% each year. Ultraviolet (UV) radiation from excessive sun exposure is an important carcinogenic risk factor, with penetration varying greatly throughout the country. Consequently, an individual's geographic location may play a role in how much exposure to high UV index rays they receive throughout their lifetime. The objective of this study was to use the surveillance, epidemiology, and end results SEER database to study geographic trends in incidence, staging, and mortality of pediatric melanoma between 2009 and 2019 and determine their relation to UV index in the United States. MATERIALS AND METHODS: A retrospective analysis of pediatric patients from 0 to 19 years in the surveillance, epidemiology, and end results 22 registries incidence database (17 states) and 17 registries incidence-based mortality database (12 states) was conducted from 2009 to 2019 based on a diagnosis of melanoma of the skin using the International Classification of Childhood Cancer codes for malignant melanoma. Data regarding patient demographics and incidence, staging, and mortality per state were extracted. Incidence data were geographically mapped and mean UV index distribution from www.epa.gov was superimposed. RESULTS: Incidence of pediatric melanoma was stratified regionally, with a total of 1665 new cases from 2009 to 2019. The Northeast had 393 new cases, with 244 (62.1%) localized cases, 55 (14.0%) lymph node-invasive and metastatic (advanced) cases, and 6/146 (4.1%) cases of mortality. The Midwest had 209 new cases, with 123 (58.9%) localized cases, 29 (13.9%) advanced cases, and 1/57 (1.8%) case of mortality. The South had 487 new cases, with 224 (46.0%) localized cases, 104 (21.4%) advanced cases, and 8/232 (3.4%) cases of mortality. The West had 576 new cases, with 364 (63.2%) localized cases, 82 (14.2%) advanced cases, and 23/551 (4.2%) cases of mortality. Mean UV index was 4.4 in the Northeast, 4.8 in the Midwest, 7.3 in the South, and 5.5 in the West from 2006 to 2020. The regional difference in incidence was not statistically significant. There was a statistically significant increased number of advanced cases in the South as compared to the Northeast (P = 0.005), West (P = 0.002), and Midwest (P = 0.02), with a significant correlation coefficient of 0.7204 between advanced cases and mean UV index in the South. CONCLUSIONS: There is a statistically significant increased incidence of lymph node-invasive and metastatic pediatric melanoma cases in the South as compared to the West, Northeast, and Midwest regions of the United States. There is also a significant correlation between the incidence of lymph node-invasive and metastatic pediatric melanoma cases and UV index. In the pediatric population, there is no statistically significant association between total incidence and mortality of melanoma and geographic region. There is an increased prevalence of pediatric melanoma seen in White and female patients. This suggests that an individual's geographic location in the United States during childhood may play a role in their likelihood of malignant melanoma development, advanced-stage melanoma development, and mortality.

Modeling acute and cumulative erythemal sun exposure on vulnerable body sites during beach vacations utilizing behavior-encoded 3D body models.

Vacationers in a high-solar-intensity beach setting put themselves at risk of ultraviolet radiation (UV) over-exposure that can lead to acute and chronic health consequences including erythema, photoaging, and skin cancer. There is a current gap in existing dosimetry work on capturing detailed time-resolved anatomical distributions of UV exposure in the beach vacation setting. In this study, a radiative transfer model of the solar conditions of Tampa Bay, St. Petersburg, Florida, USA (27.8°N, 82.8°W) is combined with an in silico three-dimensional body model and data on typical beach vacation behaviors to calculate acute and cumulative body-site-specific UV exposure risk during a beach vacation. The resulting cumulative UV exposure calculated for a typical mix of clothing choices, settings, and activities during a week-long (7-day) beach vacation is 172.2 standard erythemal doses (SED) at the forearm, which is comparable with the average total annual UV exposure of European and North American residents and consistent with existing dosimetry studies. This model further estimates that vacationers choosing to spend a full day exclusively in the beach or pool setting can experience UV exposure in excess of 50 SED a day at multiple body sites. Such exposure indicates that significant sun protective measures would be required to prevent sunburn across all skin types in this setting. This work clarifies the significant role that beach vacations play in UV exposure and corresponding acute and cumulative health risks and highlights the importance of behavioral choices (including clothing, activity and photoprotection) as crucial factors in differentiating personal solar exposure risks.

Relationship between ozone and biologically relevant UV at 4 NDACC sites.

Clouds and aerosols, as well as overhead ozone, can have large effects on ultraviolet (UV) irradiances. We use statistical methods to remove cloud effects and mean aerosol effects from spectral UV irradiance measurements to investigate the relationship between UV and total column ozone. We show that for fixed solar zenith angles (SZA), seasonal changes in ozone lead to marked changes in clear-sky UV irradiances. Such effects are larger at mid-latitudes than in the tropics. At mid-latitudes, the minimum ozone amount over the course of a year can be about 50 percent of its maximum, with the lowest values in autumn and the highest values in spring. These seasonal ozone changes lead to UV Index (UVI) values in autumn that can exceed those in spring at the same SZA by nearly a factor of two. Differences are even larger for UV spectra weighted by the action spectra for DNA-damaging UV, and for cutaneous previtamin D production. In some cases, the seasonal increase exceeds a factor of 4. The analysis experimentally demonstrates the limits of applicability of the concept of constant Radiative Amplification Factors (RAFs) for estimating effects of changes in ozone for some weighting functions. Changes in DNA-weighted UV and erythemally weighted UV are well represented by the published RAFs. However, there are large SZA dependencies in the case of UVB and vitamin D-weighted UV. For all weightings considered, RAFs calculated from the observations as a function of SZA show similar dependencies between sites, in good agreement with published values, independently of the ozone data source. High quality measurements show that natural variations in ozone are responsible for huge variations in biologically damaging UV, with seasonal changes at fixed solar zenith angles sometimes exceeding a factor of four. The measured changes from thousands of spectra agree well with calculations over a wide range of solar zenith angles.

Impact of population density and weather on COVID-19 pandemic and SARS-CoV-2 mutation frequency in Bangladesh.

Coronavirus disease-2019 (COVID-19) has caused the recent pandemic worldwide. Research studies are focused on various factors affecting the pandemic to find effective vaccine or therapeutics against COVID-19. Environmental factors are the important regulators of COVID-19 pandemic. This study aims to determine the impact of weather on the COVID-19 cases, fatalities and frequency of mutations in Bangladesh. The impacts were determined on 1, 7 and 14 days of the case. The study was conducted based on Spearman's correlation coefficients. The highest correlation was found between population density and cases (rs = 0.712). Among metrological parameters, average temperature had the strongest correlation (rs = -0.675) with the cases. About 82% of Bangladeshi isolates had D614G at spike protein. Both temperature and UV index had strong effects on the frequency of mutations. Among host factors, coinfection is highly associated with frequency of different mutations. This study will give a complete picture of the effects of metrological parameters on COVID-19 cases, fatalities and mutation frequency that will help the authorities to take proper decisions.

Ultraviolet Radiation Environment of a Tropical Megacity in Transition: Mexico City 2000-2019.

Tropical regions experience naturally high levels of UV radiation, but urban pollution can reduce these levels substantially. We analyzed 20 years of measurements of the UV index (UVI) at several ground-level locations in the Mexico City Metropolitan Area and compared these data with the UVI values derived from the satellite observations of ozone and clouds (but not local pollution). The ground-based measurements were systematically lower than the satellite-based estimates by ca. 40% in 2000 and 25% in 2019. Calculations with a radiative transfer model using observed concentrations of air pollutants explained well the difference between satellite and ground-based UVI and showed specific contributions from aerosols, O3, NO2, and SO2 in decreasing order of importance. Such large changes in UV radiation between 2000 and 2019 have important implications ranging from human health (skin cancer and cataract induction) to air pollution control (photochemical smog formation).

A DNN-Based UVI Calculation Method Using Representative Color Information of Sun Object Images.

As outdoor activities are necessary for maintaining our health, research interest in environmental conditions such as the weather, atmosphere, and ultraviolet (UV) radiation is increasing. In particular, UV radiation, which can benefit or harm the human body depending on the degree of exposure, is recognized as an essential environmental factor that needs to be identified. However, unlike the weather and atmospheric conditions, which can be identified to some extent by the naked eye, UV radiation corresponds to wavelength bands that humans cannot recognize; hence, the intensity of UV radiation cannot be measured. Recently, although devices and sensors that can measure UV radiation have been launched, it is very difficult for ordinary users to acquire ambient UV radiation information directly because of the cost and inconvenience caused by operating separate devices. Herein, a deep neural network (DNN)-based ultraviolet index (UVI) calculation method is proposed using representative color information of sun object images. First, Mask-region-based convolutional neural networks (R-CNN) are applied to sky images to extract sun object regions and then detect the representative color of the sun object regions. Then, a deep learning model is constructed to calculate the UVI by inputting RGB color values, which are representative colors detected later along with the altitude angle and azimuth of the sun at that time. After selecting each day of spring and autumn, the performance of the proposed method was tested, and it was confirmed that accurate UVI could be calculated within a range of mean absolute error of 0.3.

Record-Breaking Increases in Arctic Solar Ultraviolet Radiation Caused by Exceptionally Large Ozone Depletion in 2020.

Measurements of solar ultraviolet radiation (UVR) performed between January and June 2020 at 10 Arctic and subarctic locations are compared with historical observations. Differences between 2020 and prior years are also assessed with total ozone column and UVR data from satellites. Erythemal (sunburning) UVR is quantified with the UV Index (UVI) derived from these measurements. UVI data show unprecedently large anomalies, occurring mostly between early March and mid-April 2020. For several days, UVIs observed in 2020 exceeded measurements of previous years by up to 140%. Historical means were surpassed by more than six standard deviations at several locations in the Arctic. In northern Canada, the average UVI for March was about 75% larger than usual. UVIs in April 2020 were elevated on average by about 25% at all sites. However, absolute anomalies remained below 3.0 UVI units because the enhancements occurred during times when the solar elevation was still low.

Use of smartphone apps to monitor human exposure to solar radiation: Comparison between predicted and measured UV index values.

The Ultra-Violet Index (UVI) is widespread used to communicate the UV radiation intensity to the general public. The knowledge of the UVI value and of its daily variation is essential for many techniques for monitoring the personal exposure to UV radiation. The UVI values are usually provided by the meteorological services and nowadays it is very common to find UVI forecast tools even in smartphone apps. In this paper, with the aim to evaluate the prediction accuracy of six smartphone apps, a measurement campaign of UVI has been carried out. The measurements have been conducted for the site of Pisa (central Italy), using a portable photoradiometer equipped with a UV erythemal irradiance probe (operating range 250-400 nm). The measured UVI values have been compared with the predicted UVI values (using smartphone apps). Bland-Altman and Passing-Bablok methods have been used to compare the data, the comparison has been conducted on the basis of 90 different UVI measurements, taken at different times, different days and different sky conditions. From the comparison between measured and predicted UVI values it has been possible to observe a general poor accuracy of the apps. The percentage deviations between measured and predicted UVI values were quite high and only one app was able to predict more than 70% of the measured data with an average percentage deviation lower than 30%.

On the Relationship Between Sun Exposure and All-Cause Mortality.

Increasing sun exposure is related to lower prevalence of death in cardiovascular disease (CVD), type 2 diabetes, and other noncancer non-CVD. In this chapter we aim to make a short update on the knowledge regarding sun exposure and all-cause mortality. Data support the hypothesis that low sun exposure habits are a major risk factor for all-cause mortality. Low sun exposure is related to an increased risk of death due to CVD and noncancer/non-CVD, and a minor reduction in risk of cancer. Active sun exposure habits have a dual effect; it increases the incidence of skin cancer, but also improves the prognosis in terms of all-cause mortality. In a low solar intensity region, we should carefully assess both risk and benefits of sun exposure in order to obtain balanced recommendations.

Awareness, understanding, use, and impact of the UV index: A systematic review of over two decades of international research.

The ultraviolet radiation index (UVI) was adopted internationally to raise awareness about and encourage the public to protect their skin from skin cancer. The current paper is a systematic review of over 20 years of research investigating awareness, comprehension, use, and impact of the UVI. Thirty-one studies were included from the USA, Canada, Europe, Australia, New Zealand, and elsewhere. Awareness of the UVI varies by country, with samples from some countries demonstrating high awareness. However, comprehension and use of the UVI to inform sun safety behaviors are typically much lower. In fact, greater UVI awareness has sometimes been associated with riskier UV-related behaviors such as intentional tanning. Fewer studies have evaluated interventions, and their results have been mixed. In summary, more research is needed to determine how to help the public understand and use the UVI for effective skin protection. This review offers suggestions for future use of and research with the UVI.

Development of a UV Index Sensor-Based Portable Measurement Device with the EUVB Ratio of Natural Light.

Ultraviolet (UV) rays are electromagnetic waves that account for about 5% of solar light, and when overexposed, they pose malevolent effects on human skin and health. However, with recent reports on the beneficial effects of some wavelength bands of UV rays, people's interest in UV information has increased. This has resulted in requiring not just simple information, such as the amount of UV or UV index (UVI), but detailed UV information that directly affects health, such as EUVB (erythemally weighted UVB). However, calculating EUVB, which can be done by applying the erythemal weighted function on the intensity value in wavelength, requires specialized optical measurement devices, which cannot be easily accessed by the general public; furthermore, public institutions' UV information services do not offer EUVB information for individuals. Therefore, the present study proposes a UVI sensor-based portable measurement device, with which the general public can have easy access to UV-related information. The proposed device comprises a UVI sensor that can measure the intensity of erythemal UV radiation, a Bluetooth Low Energy (BLE) module that supports communication, and a micro controller unit (MCU) for key operations. In addition, it applies the ratio of EUVB by month/time, resulting from the actual analysis of natural light to calculate the EUVB and provides the amount of UVI and EUVB to check if they meet conditions required for outdoor activities through the device and smartphone applications. The applicability of the proposed device was verified by the measurement performance comparison test with the standard device, a spectrometer (CAS 140 CT), which showed an average error of 0.045 for UVI and 0.0014 W/m². The proposed device's offering of UV-related information such as UVI and EUVB to the user is expected to prevent potential damage due to exposure to UV and to support healthy outdoor activities.

Natural exposure to ultraviolet-B radiation in two species of chameleons from Madagascar.

Many reptiles require ultraviolet-B radiation between 290 and 315 nm (UV-B) to synthesize vitamin D3 and process dietary calcium. In captivity, exposure to too little or too much UV-B can result in health problems such as metabolic bone disease. While it is recognized that UV-B is necessary to successfully maintain many reptiles in captivity, the actual levels of UV-B that species are exposed to in nature is poorly known. We measured the UV-B exposure of two species of chameleon (Calumma brevicorne and C. nasutum) in the field in Madagascar over a period of four months. We found that both species were exposed to less UV radiation than that which was available in full sun. Only on rare occasions were chameleons observed in areas with a UV Index (UVI) greater than 3.0, and the median UVI for both species was only 0.3. There was no daily temporal pattern in UV exposure for C. nasutum, but C. brevicorne was found in areas with lower UV levels in the late afternoon when compared to late morning. Additionally, C. nasutum males showed higher UV exposure than females in late morning. Our results suggest that both C. brevicorne and C. nasutum can be classified as Ferguson Zone 1 species, and should be provided with a UV-B gradient in captivity that offers access to UV-B radiation as well as adequate shaded refuge.

Sex differences in the association of cutaneous melanoma incidence rates and geographic ultraviolet light exposure.

BACKGROUND: Cutaneous melanoma (CM) incidence rates continue to increase, and the reasons are unknown. Previously, we reported a unique age-specific sex difference in melanoma that suggested additional causes other than solar ultraviolet (UV) radiation. OBJECTIVE: This study attempted to understand whether and how UV radiation differentially impacts the CM incidence in men and women. METHODS: CM data and daily UV index (UVI) from 31 cancer registries were collected for association analysis. A second dataset from 42 US states was used for validation. RESULTS: There was no association between log-transformed female CM rates and levels of UVI, but there was a significant association between male rates and UVI and a significant association between overall rates and UVI. The 5-year age-specific rate-UVI association levels (represented by Pearson's coefficient ρ) increased with age in men, but age-specific ρ levels remained low and unchanged in women. The significant rate-UVI association in men and nonassociation in women was validated in a population of white residents of the United States. LIMITATIONS: Confounders, including temperature and latitude, are difficult to separate from UVI. CONCLUSIONS: Ambient UVI appears to be associated with melanoma incidence in males but not in females.

Association between unprotected ultraviolet radiation exposure and recurrence of ocular herpes simplex virus.

Studies have suggested that exposure to ultraviolet (UV) light may increase risk of herpes simplex virus (HSV) recurrence. Between 1993 and 1997, the Herpetic Eye Disease Study (HEDS) randomized 703 participants with ocular HSV to receipt of acyclovir or placebo for prevention of ocular HSV recurrence. Of these, 308 HEDS participants (48% female and 85% white; median age, 49 years) were included in a nested study of exposures thought to cause recurrence and were followed for up to 15 months. We matched weekly UV index values from the National Oceanic and Atmospheric Administration to each participant's study center and used marginal structural Cox models to account for time-varying psychological stress and contact lens use and selection bias from dropout. There were 44 recurrences of ocular HSV, yielding an incidence of 4.3 events per 1,000 person-weeks. Weighted hazard ratios comparing persons with ≥8 hours of time outdoors to those with less exposure were 0.84 (95% confidence interval (CI): 0.27, 2.63) and 3.10 (95% CI: 1.14, 8.48) for weeks with a UV index of <4 and ≥4, respectively (ratio of hazard ratios = 3.68, 95% CI: 0.43, 31.4). Though results were imprecise, when the UV index was higher (i.e., ≥4), spending 8 or more hours per week outdoors was associated with increased risk of ocular HSV recurrence.

The epidemiology of skin cancer by UV index: cross-sectional analysis from the 2019 behavioral risk factor surveillance survey.

The extent to which the Ultraviolet (UV) index is associated with the prevalence of melanoma and keratinocyte cancer in the United States is not clear. We conducted a cross-sectional study using the Center for Disease Control and Prevention's (CDC) 2019 Behavioral Risk Factor Surveillance System (BRFSS) telephone interview survey to investigate the epidemiology of skin cancer in the US including age, household income, education, and marital and employment status. Of non-Hispanic white respondents, 9.6% (N = 29,925) reported a being told of a skin cancer diagnosis. The prevalence of skin cancer was significantly higher in high UV (> / = 8) states (11.8%, N = 36,575) than in medium UV (6-7) (9.0%, N = 27,812) and lower UV (< / = 5) (7.8%, N = 24,083) states (p < .0001). Respondents from a medium UV or high UV state had higher odds (1.21 [1.15-2.27], 1.55[1.47-1.63], respectively) of reporting a skin cancer diagnosis than those from a low UV state. The association of UV index with lifetime skin cancer prevalence reinforces the importance of educating patients on preventive practices such as avoidance of tanning beds and usage of UV protection with clothing and sunscreen.

Sunscreen use amongst US adults: a national survey.

One in five Americans will develop skin cancer before the age of 70. Consistent sunscreen use can help decrease the prevalence of this. This study assesses the general knowledge of United States citizens on sunscreen use, frequency of usage, common behaviors of sunscreen usage, and use of sunscreen based on knowledge of sun protection. We created a 14-question anonymous web-based survey that was distributed amongst a third-party polling service. The polling service conducted random recruitment of participants based on inclusion criteria. Results from 200 participants were then analyzed using JMP Pro 16 for the Mac [11]. Fishers two tailed exact test was used along with Wilcoxon's rank- sum test. The results of the survey found that 11% of the participants report not wearing sunscreen at all, 13.5% wear sunscreen daily, the most common reason for sunscreen use was avoidance of sunburns (50%, n = 100), most people learn about the importance of sunscreen from their parents/family members (46.5%, n = 93), and 66.5% of the participants feel that sunscreen education should be included in schools (n = 133). Furthermore, the participants in the lowest income bracket were less likely to apply sunscreen. In conclusion, our survey found that most US residents are aware about sunscreen's role in protection from UV rays, however, most citizens continue to use it inconsistently.

The dynamic behaviour of sunscreens under in-service conditions.

Discussion continues over various aspects of sunscreen science: regulation, test methods, sun protection factor (SPF), labelling claims, potentially harmful components, among others. In this paper the UV transmission properties of a number of commercial sunscreens have been determined at constant sunscreen film thickness under different local UV Index conditions. The data demonstrate difficulties facing the public and the sunscreen industry as a whole, even though SPF values and other data stated on the sunscreen packaging are assumed to be correct according to standard testing methods. This work has shown that at realistic application rates the critical factors are the intensity of the incident solar radiation and the accumulated erythema UV dose transmitted over time. In one example, on 'Extreme' UV Index days, an SPF 30 sunscreen under test transmitted one minimal erythema dose (MED) of UV in only 35 min. In another example, although it should not, in theory, transmit one MED until several hours of exposure, this level was reached in 1 h by an SPF 50 sunscreen under these typical Australian summer conditions (UV Index 12) in Wollongong, NSW (34.4°S). Such properties could have severe consequnces if these sunscreens were used by individuals with Fitzpatrick Skin Type 1, organ transplant recipients or other immuno-compromised individuals.

On the global trends and spread of the COVID-19 outbreak: preliminary assessment of the potential relation between location-specific temperature and UV index.

The novel coronavirus, since its first outbreak in December, has, up till now, affected approximately 114,542 people across 115 countries. Many international agencies are devoting efforts to enhance the understanding of the evolving COVID-19 outbreak on an international level, its influences, and preparedness. At present, COVID-19 appears to affect individuals through person-to-person means, like other commonly found cold or influenza viruses. It is widely known and acknowledged that viruses causing influenza peak during cold temperatures and gradually subside in the warmer temperature, owing to their seasonality. Thus, COVID-19, due to its regular flu-like symptoms, is also expected to show similar seasonality and subside as the global temperatures rise in the northern hemisphere with the onset of spring. Despite these speculations, however, the systematic analysis in the global perspective of the relation between COVID-19 spread and meteorological parameters is unavailable. Here, by analyzing the region- and city-specific affected global data and corresponding meteorological parameters, we show that there is an optimum range of temperature and UV index strongly affecting the spread and survival of the virus, whereas precipitation, relative humidity, cloud cover, etc. have no effect on the virus. Unavailability of pharmaceutical interventions would require greater preparedness and alert for the effective control of COVID-19. Under these conditions, the information provided here could be very helpful for the global community struggling to fight this global crisis. It is, however, important to note that the information presented here clearly lacks any physiological evidences, which may merit further investigation. Thus, any attempt for management, implementation, and evaluation strategies responding to the crisis arising due to the COVID-19 outbreak must not consider the evaluation presented here as the foremost factor.

Evaluation of a Sunscreen Product Compared with Reference Standards P3, P5 and P8 in Outdoor Conditions: a Randomized, Double-Blinded, Intra-individual Study in Healthy Subjects.

INTRODUCTION: The shortcomings of standardized sunscreen testing have been discussed in recent years, noting differences between how sunscreens perform in indoor clinical (in vivo) laboratory testing compared with real-life conditions. We previously developed an outdoor clinical method for ranking sunscreens by performance level. We used this method to test the performance of a new broad-spectrum sunscreen against International Organization for Standardization (ISO) reference products P3, P5 and P8. METHODS: Sixty-five healthy volunteers with individual typology angle (ITA) ≥ 28° (light to intermediate skin colour) participated in an outdoor study in Mauritius. Test areas were marked on their backs, which were treated with the different products: one commercially available broad-spectrum sun protection factor (SPF) 50 sunscreen [investigational product (IP)] and the three reference products P3 (SPF 15), P5 (SPF 30) and P8 (SPF 50+) from ISO norm 24444:2019 for SPF testing. The test areas were exposed for 2-3 h, depending on the baseline skin colour. They were also compared with an unprotected positive control area and a non-exposed negative control area. Clinical and colorimetry assessment of erythema and pigmentation were performed at 24 h and 8 days, respectively. RESULTS: Overall, according to this outdoor clinical testing method, the sunscreens' efficacy was ranked in an appropriate order given their established SPF levels, with higher SPFs giving greater protection against erythema and pigmentation. Between the different levels of SPF, the differences were statistically significant, for both clinical and colorimetry assessments. The new broad-spectrum SPF 50 IP performed similarly to the SPF 50+ (P8) reference product. Even the highest SPF products, SPF 50 and SPF 50+, had some instances of photoprotection failure. CONCLUSION: These findings confirm the feasibility of this outdoor clinical testing method in ranking sunscreens and provide further evidence, in addition to standardized SPF and UVA protection factor (UVAPF) testing, on how this new broad-spectrum SPF 50 sunscreen performs in extreme outdoor solar exposure: in line with reference product P8 (SPF 50+). TRIAL REGISTRATION NO: ISRCTN95394014.