Standard Erythema Dose Research Articles

A One-Month Monitoring of Exposure to Solar UV Radiation of a Group of Construction Workers in Tuscany

Solar radiation exposure at work is a relevant heath risk in the construction sector. Our objective was to monitor for a full month the individual solar ultraviolet radiation (UVR) exposure of a group of three construction workers active in Siena (latitude = 43°19′ N), a town in Tuscany (Italy). We used personal electronic dosimeters “X-2012-10” (Gigahertz, Turkenfeld, Germany) to register the UV irradiance in the UVA and UVB/C regions separately and we consulted a specific database to retrieve the corresponding ambient erythemal UVR dose (cloud-free conditions). In spring, construction workers from central Italy received a quite variable UVR dose, between 0.9 standard erythemal doses (SED) and 15.6 SED/day, 5.7 on average. Considering the proportion with respect to the potential environmental exposure, personal exposure resulted between 2.7% and 31.2% of the ambient erythemal dose, with a mean value of 12.5%. Cumulatively, the three construction workers received in one working month a UVR dose of more than 120 SED. In a year, we estimated that a construction worker from Tuscany region is exposed to about 750 SED. This data demonstrates that construction workers in Italy are exposed to extremely high levels of solar UVR, with a relevant risk of developing adverse health effects related to the potential accumulation of UVR-induced damage in susceptible biological tissues, such as the skin and the eyes.

Solar UV Radiation in the Tropics: Human Exposure at Reunion Island (21° S, 55° E) during Summer Outdoor Activities.

Reunion Island is a popular tourist destination with sandy beaches, an active volcano (Piton de la Fournaise), and Piton des Neiges, the highest and most dominant geological feature on the island. Reunion is known to have high levels of solar ultraviolet radiation (UVR) with an ultraviolet index (UVI) which can reach 8 in winter and 16 in summer (climatological conditions). UVR has been linked to skin cancer, melanoma, and eye disease such as cataracts. The World Health Organization (WHO) devised the UVI as a tool for expressing UVR intensity. Thresholds ranging from low (UVI 1–2) to extreme (UVI > 11) were defined depending on the risk to human health. The purpose of the study was to assess UVR exposure levels over three of the busiest tourist sites on the island. UVR was measured over several hours along popular hiking trails around Piton de la Fournaise (PDF), Piton des Neiges (PDN), and St-Leu Beach (LEU). The results were compared with those recorded by the local UV station at Saint-Denis. In addition, cumulative standard erythemal dose (SED) was calculated. Results showed that UVI exposure at PDF, PDN, and LEU were extreme (>11) and reached maximum UVI levels of 21.1, 22.5, and 14.5, respectively. Cumulative SEDs were multiple times higher than the thresholds established by the Fitzpatrick skin phototype classification. UVI measurements at the three study sites showed that Reunion Island is exposed to extreme UVR conditions. Public awareness campaigns are needed to inform the population of the health risks related to UVR exposure.

"Beach Lifeguards' Sun Exposure and Sun Protection in Spain".

BackgroundSunburn is the main avoidable cause of skin cancer. Beach lifeguards spend many hours exposed to the effects of solar radiation during their work day, precisely at times of the year when levels of solar irradiation are highest. The aim of this study is to quantify the risk to beach lifeguards of sun exposure.MethodsA descriptive cross-sectional study was carried out in the Western Costa del Sol, southern Spain, during the summer of 2018. The research subjects were recruited during a skin cancer prevention course for beach lifeguards. All participants were invited to complete a questionnaire on their habits, attitudes, and knowledge related to sun exposure. In addition, ten were specially monitored using personal dosimeters for three consecutive days, and the results were recorded in a photoprotection diary. A descriptive analysis (mean and standard deviation for the quantitative variables) was performed, and inter-group differences were evaluated using the Mann–Whitney U test.ResultsTwo hundred fifteen lifeguards completed the questionnaire, and 109 met the criteria for inclusion in this analysis. The mean age was 23.8 years (SD: 5.1), 78.0% were male, 71.5% were phototype III or IV (Fitzpatrick's phototype), and 77.1% had experienced at least one painful sunburn during the previous summer. The mean daily personal ultraviolet exposure per day, the minimal erythema dose, and the standard erythema dose, in J/m2, were 634.7 [standard deviation (SD): 356.2], 2.5 (SD: 1.4) and 6.35 (SD: 3.6), respectively.ConclusionBeach lifeguards receive very high doses of solar radiation during the work day and experience correspondingly high rates of sunburn. Intervention strategies to modify their sun exposure behavior and working environment are necessary to reduce the risk of skin cancer for these workers and to promote early diagnosis of the disease.

Sex as a Risk Factor for Solar Ultraviolet Radiation Exposure?-Dosimetry in Danish Outdoor Workers.

Solar ultraviolet radiation (UVR) exposure is a known risk factor for the development of skin cancer. Heterogeneity in solar UVR exposure may explain the diversity in skin cancer incidence between men and women. This, however, has not previously been investigated in Danish outdoor workers using UVR dosimetry. The aim of this study was to evaluate sex differences in solar UVR dosimetry in Danish outdoor workers on working and leisure days. A cross‐sectional design was used to collect dosimetry data during the Danish summer season (May to September). Analysis was based on an electronic questionnaire and dosimetry data from 450 outdoor workers (88 women, 362 men). Dosimetry data were reported as standard erythema dose (SED). The daily median SED (Interquartile range) on working days was 1.6 (2.5) in men and 1.5 (2.1) in women while on leisure days it was 0.5 (1.4) in men and 0.6 (1.3) in women. Analysis by multiple linear regression did not show any association between daily median SED and sex on either working or leisure days. In conclusion, solar UVR exposure in Danish outdoor workers did not vary according to sex.

Strategic Task and Break Timing to Reduce Ultraviolet Radiation Exposure in Outdoor Workers.

Objectives: Public health messaging about sun avoidance strategies is often not practical for outdoor workers. The objective of this study was to use personal monitoring data to determine when peak UVR exposure occurs for outdoor workers, estimate how much UVR could be reduced by altering the timing of shady tasks or breaks during peak exposure times, and descriptively compare these to peak periods of ambient UVR. Ultimately, we aim to provide evidence-based sun avoidance recommendations for outdoor workers in British Columbia, Canada.Methods: UVR exposure data [standard erythemal dose (SED)] were collected during the 2013 summer months in Vancouver, using personal electronic dosimeters that sampled once per minute for an average of 4.4 working days (range: 1–7 days). Mixed-effect models were used to estimate the 60-, 30-, and 15-min time intervals at which maximum exposure occurred for the months of July and August. Using these time intervals, UVR exposure during peak periods was summarized as SED and as a percentage of the total daily exposure. Ambient UVR was also collected using data from the nearest Brewer spectrophotometer station and parallel analyses were conducted.Results: There were 73 workers and 321 participant-days available for analysis. Models indicated that periods of maximum exposure for 15-, 30-, and 60-min intervals began at 12:28, 12:17 pm, and 11:52 am, respectively, for sunny days in July. These periods were similar in August. The median exposure during these time periods and the potential for reducing UVR was 0.03 SED (2.8% potential daily exposure reduction), 0.09 SED (7.1%), and 0.18 SED (15.9%), respectively. However, there was a large range in exposure estimates as some workers experienced up to 84.8% of their exposure in the peak 60-min interval.Conclusion: Skin cancer prevention messaging does not include practical messages for outdoor workers and providing times of peak UVR help to identify times when the greatest reductions in exposure can occur. Prevention measures including shady breaks, increased sun protection, and task reorganization during these peak times are recommended during these peak times to reduce UVR exposure among those at highest risk.

Solar ultraviolet radiation exposure among outdoor workers in Alberta, Canada

BackgroundOutdoor workers are at risk of prolonged and high solar ultraviolet radiation (UVR) exposure, which is known to cause skin cancer. The objectives of this study were to characterize the UVR exposure levels of outdoor workers in Alberta, Canada, and to investigate what factors may contribute to their exposure. MethodsThis study collected objective solar UVR measurements from outdoor workers primarily in Alberta during the summer of 2019. Workers were recruited via the management or health and safety teams from building trade unions and employers. Calibrated, electronic UVR dosimeters were worn by workers on their hardhats, wrists, or lapels for five working days. Data on workers’ demographics, jobs, sun protection behaviors, and personal risk factors were collected using questionnaires, and meteorological data for each sampling day were noted. Mean daily exposure measured as the standard erythemal dose (SED) was calculated and compared to the international occupational exposure limit guideline (1.3 SED). Marginal models were developed to evaluate potential determinants of occupational solar UVR exposure. ResultsIn total, 883 measurements were collected from 179 workers. On average, workerswere exposed to 1.93 SED (range: 0.03–16.63 SED) per day. Just under half of workers (45%) were exposed to levels exceeding the international exposure limit guideline. In the bivariate analyses, landscape and maintenance workers, as well as trade and recreation workers, had the highest levels of exposure (average: 2.64 and 1.84 SED, respectively). Regional variations were observed, with the “other” cities/regions (outside of Edmonton and Calgary) experiencing the highest average levels (2.60 SED). Workers who placed the dosimeters on their hardhats experienced higher levels compared to the other groups. Exposure was highest on sunny and mixed days. Education, trade, city, dosimeter placement, forecast, hair colour, and number of hours outside were included in the final exposure model, of which trade, dosimeter placement, forecast, and number of hours outside at work were statistically significant. ConclusionsExposure to elevated solar UVR levels is common among outdoor workers in Alberta. The study findings can help inform future monitoring studies and exposure reduction initiatives aimed at protecting workers.

EFFICACY OF ORAL VITAMIN D SUPPLEMENTATION OR SIMULATED SUNLIGHT ON BONE DURING MILITARY TRAINING

25-hydroxyvitamin D (25(OH)D) ≥50 nmol·L-1 is essential for bone health. Vitamin D deficiency during arduous training has implications for increased stress fracture risk. Vitamin D is mainly synthesised from skin exposure to the sun; around 20% of vitamin D is obtained from the diet. PURPOSE: This study compared the efficacy of vitamin D supplementation by oral pill versus simulated sunlight on bone macro- and micro-architecture during a 13-week military training course in winter. METHODS: Eighty male infantry recruits (mean ± SD, age 22 ± 3 years, height 1.78 ± 0.07 m, body mass 77.9 ± 10.7 kg) received oral vitamin D3 (1,000 IU·D-1 for 4 weeks and then 400 IU·d-1 for 8 weeks, n = 21), an oral placebo (n = 19), solar-simulated radiation (SSR, 1.3 × standard erythemal dose in T-shirt and shorts, 3 d·wk-1 for 4 weeks and 1 d·wk-1 for 8 weeks, n = 22), or placebo SSR (n = 18). Total 25(OH)D was measured by LC-MS/MS in week 1, 5 and 13, and bone density and structure was assessed at the ultra-distal dominant tibia by HR-pQCT (Xtreme CTI, Scanco) in week 1 and 13. RESULTS: Oral vitamin D3 and SSR increased 25(OH)D from week 1 (51 ± 22 and 43 ± 21 nmol·L-1) to week 5 (78 ± 23 and 79 ± 15 nmol·L-1) and week 13 (75 ± 15 and 76 ± 12 nmol·L-1 , P < 0.001). The oral and SSR placebos did not change 25(OH)D from week 1 (51 ± 40 and 41 ± 17 nmol·L-1) to week 5 (45 ± 4 and 41 ± 16 nmol·L-1), but 25(OH)D increased in both groups by week 13 (60 ± 4 and 65 ± 15 nmol·L-1, P ≤ 0.010). Supplementation and training did not affect total, trabecular or cortical volumetric bone mineral density, cortical area, trabecular volume, number or thickness, or cortical pore diameter (main effects of time, P ≥ 0.105; group × time interactions, P ≥ 0.258). Training increased cortical thickness (1.30 ± 0.25 to 1.32 ± 0.25 mm), and reduced trabecular area (682 ± 133 to 680 ± 133 mm2) and spacing (360 ± 58 to 345 ± 71 μm, main effects of time, P ≤ 0.041), but supplementation had no effect (group × time interactions, P ≥ 0.181). There was a significant group × time interaction for cortical perimeter (P = 0.033) and porosity (P = 0.049); training had no effect on either measure for any group (P ≥ 0.068). CONCLUSION: Vitamin D supplementation in winter, using strategies to increase total 25(OH)D above 50 nmol·L-1, exerted no effect on bone macro- or micro-architecture beyond the osteogenic effects of exercise training.

The Melanoma Genomics Managing Your Risk Study randomised controlled trial: statistical analysis plan

BackgroundThe Melanoma Genomics Managing Your Risk Study is a randomised controlled trial that aims to evaluate the efficacy of providing information on personal genomic risk of melanoma in reducing ultraviolet radiation (UV) exposure, stratified by traditional risk group (low or high phenotypic risk) in the general population. The primary outcome is objectively measured total daily Standard Erythemal Doses at 12 months. Secondary outcomes include UV exposure at specific time periods, self-reported sun protection and skin-examination behaviours, psychosocial outcomes, and ethical considerations surrounding offering genomic testing at a population level. A within-trial and modelled economic evaluation will be undertaken from an Australian health system perspective to assess the cost-effectiveness of the intervention.ObjectiveTo publish the pre-determined statistical analysis plan (SAP) before database lock and the start of analysis.MethodsThis SAP describes the data synthesis, analysis principles and statistical procedures for analysing the outcomes from this trial. The SAP was approved after closure of recruitment and before completion of patient follow-up. It outlines the planned primary analyses and a range of subgroup and sensitivity analyses. Health economic outcomes are not included in this plan but will be analysed separately. The SAP will be adhered to for the final data analysis of this trial to avoid potential analysis bias that may arise from knowledge of the outcome data.ResultsThis SAP is consistent with best practice and should enable transparent reporting.ConclusionThis SAP has been developed for the Melanoma Genomics Managing Your Risk Study and will be followed to ensure high-quality standards of internal validity and to minimise analysis bias.Trial registrationProspectively registered with the Australian New Zealand Clinical Trials Registry, ID: ACTR N12617000691347. Registered on 15 May 2017.

A Comparison of Solar Ultraviolet Radiation Exposure in Urban Canyons in Venice, Italy and Johannesburg, South Africa

Urban environments can have high-risk spaces that can provide excess personal sun exposure, such as urban or street canyons, and the spaces between buildings, among others. In these urban spaces, sun exposure can be high or low depending on several factors. Polysulphone film (PSF) was used to assess possible daily solar ultraviolet radiation (UVR) exposure in urban canyons in Venice, Italy and, for the first time in Africa, in Johannesburg, South Africa. The photodegradation of PSF upon solar exposure was monitored at a wavelength of 330nm by ultraviolet-visible spectrophotometry, and the resultant change was converted to standard erythemal dose (SED) units (1 SED=100Jm-2 ). Mean daily ambient solar UVR exposure measured for Venice and Johannesburg ranged between 20-28 SED and 33-43 SED, respectively. Canyon-located PSF exposures were lower in Venice (1-9 SED) than those in Johannesburg (9-39 SED), depending mainly on the sky view factor and orientation to the sun. There was large variation in solar UVR exposure levels in different urban canyons. These preliminary results should be bolstered with additional studies for a better understanding of excess personal exposure risk in urban areas, especially in Africa.

Evaluation of Inflammation by Cytokine Production Following Combined Exposure to Ultraviolet and Radiofrequency Radiation of Mobile Phones on 3D Reconstructed Human Skin In Vitro.

The absorption of exposure to radiofrequency (RF) emitted by wireless devices leads to a high specific absorption rate in the skin. Ultraviolet (UV) radiation can induce several damages to the skin. The aim of this study was to examine whether combined, consecutive exposure to solar UV radiation and 1950 MHz RF exposure of third generation (3G) mobile system have any effect on inflammation processes in the skin. Under in vitro experiments, the inflammation process was examined by cytokines (IL-1α, IL-6, and IL-8) and MMP-1 enzyme secretion on 3D full thickness human skin model. The RF exposure was applied before or after UV irradiation, in order to study either the possible cooperative or protective effects of exposure to RF and UV. We did not find changes in cytokines due to exposure to RF alone. The RF exposure did not enhance the effects of UV radiation. There was a statistically not-significant decrease in cytokines when the skin tissues were pre-exposed to RF before being exposed to 4 standard erythemal dose (SED) UV compared to UV exposure alone. We found that RF exposure reduced the previously UV-treated MMP-1 enzyme concentration. This study might support the evaluation of the effects on the skin exposed to microwave radiation of 5G mobile technology.

Vitamin D and the hepatitis B vaccine response: a prospective cohort study and a randomized, placebo-controlled oral vitamin D3 and simulated sunlight supplementation trial in healthy adults

PurposeTo determine serum 25(OH)D and 1,25(OH)2D relationship with hepatitis B vaccination (study 1). Then, to investigate the effects on hepatitis B vaccination of achieving vitamin D sufficiency (serum 25(OH)D ≥ 50 nmol/L) by a unique comparison of simulated sunlight and oral vitamin D3 supplementation in wintertime (study 2).MethodsStudy 1 involved 447 adults. In study 2, 3 days after the initial hepatitis B vaccination, 119 men received either placebo, simulated sunlight (1.3 × standard-erythema dose, 3 × /week for 4 weeks and then 1 × /week for 8 weeks) or oral vitamin D3 (1000 IU/day for 4 weeks and 400 IU/day for 8 weeks). We measured hepatitis B vaccination efficacy as percentage of responders with anti-hepatitis B surface antigen immunoglobulin G ≥ 10 mIU/mL.ResultsIn study 1, vaccine response was poorer in persons with low vitamin D status (25(OH)D ≤ 40 vs 41–71 nmol/L mean difference [95% confidence interval] − 15% [− 26, − 3%]; 1,25(OH)2D ≤ 120 vs ≥ 157 pmol/L − 12% [− 24%, − 1%]). Vaccine response was also poorer in winter than summer (− 18% [− 31%, − 3%]), when serum 25(OH)D and 1,25(OH)2D were at seasonal nadirs, and 81% of persons had serum 25(OH)D < 50 nmol/L. In study 2, vitamin D supplementation strategies were similarly effective in achieving vitamin D sufficiency from the winter vitamin D nadir in almost all (~ 95%); however, the supplementation beginning 3 days after the initial vaccination did not effect the vaccine response (vitamin D vs placebo 4% [− 21%, 14%]).ConclusionLow vitamin D status at initial vaccination was associated with poorer hepatitis B vaccine response (study 1); however, vitamin D supplementation commencing 3 days after vaccination (study 2) did not influence the vaccination response.Clinical trial registry numberStudy 1 NCT02416895; https://clinicaltrials.gov/ct2/show/study/NCT02416895; Study 2 NCT03132103; https://clinicaltrials.gov/ct2/show/NCT03132103.

Measured UV Exposures of Ironman, Sprint and Olympic-Distance Triathlon Competitors

Triathletes present an extreme case of modelled behaviour in outdoor sport that favours enhanced exposure to solar ultraviolet radiation. This research presents personal solar ultraviolet exposures, measured using all-weather polysulphone film dosimeters, to triathletes during the distinct swimming, cycling and running stages of competitive Sprint, Olympic and Ironman events conducted within Australia and New Zealand. Measurements of exposure are made for each triathlon stage using film dosimeters fixed at a single site to the headwear of competing triathletes. Exposures are expressed relative to the local ambient and as absolute calibrated erythemally effective values across a total of eight triathlon courses (two Ironman, one half Ironman, one Olympic-distance, and four Sprint events). Competitor exposure results during training are also presented. Exposures range from between 0.2 to 6.8 SED/h (SED: standard erythema dose) depending upon the time of year, the local time of each event and cloud conditions. Cycle stage exposures can exceed 20 SED and represent the highest exposure fraction of any triathlon (average = 32%). The next highest stage exposure occurred during the swim (average = 28%), followed by the run (average = 26%). During an Ironman, personal competitor exposures exceed 30 SED, making triathlon a sporting discipline with potentially the highest personal ultraviolet exposure risk.

Exposure to Solar UV During Outdoor Construction Work in Britain.

Excessive exposure to ultraviolet (UV) radiation from the sun in summer can cause skin cancer and in Britain there are around 1500 new cases of non-melanoma skin cancer (NMSC) each year, caused by exposure to solar UV at work. Little is known about the magnitude of UV exposure amongst outdoor construction workers in Britain, although this is one of the main groups at risk. The aim of this paper is to summarise measurements of erythema-weighted UVB radiation amongst construction workers in Scotland and the Southeast of England and interpret the data in terms of the risk of NMSC. The measurements were made as part of an intervention study using short mobile phone text messages to alter worker behaviour to either reduce UV exposure in summer or increase serum vitamin D in winter; the intervention is only briefly reported here. Data were collected from 67 workers from 9 worksites, of whom 41 provided measures of UV exposure for 758 working days. Daily exposure ranged from 0 to 13.47 standard erythema dose (SED), with the mean exposure for outdoor workers being 2.0 SED and the corresponding value for indoor workers being 0.7 SED. These data were obtained from a sensor located on the back of the workers hard hat; others have measured exposure on the wrist or upper arm and these locations probably, on average, have higher levels of UV exposure. It is likely that an outdoor construction worker in Britain could accumulate sufficient solar UV exposure over 30-40 years of work to more than double their risk of NMSC. We argue that employers in Britain should take a more proactive approach to manage sun safety and they should take responsibility for skin health surveillance for their workers.

The Effect of Ultraviolet B Irradiation Compared with Oral Vitamin D Supplementation on the Well-being of Nursing Home Residents with Dementia: A Randomized Controlled Trial.

There are indications that ultraviolet B (UVB) exposure has beneficial effects on well-being through mechanisms other than vitamin D synthesis alone. We conducted a randomized controlled multicenter trial to compare the effects of UVB light and vitamin D supplementation (VD) in terms of the well-being of nursing home residents with dementia. Participants were randomly assigned to the intervention group (UVB group, n = 41; half-body UVB irradiation, twice weekly over 6 months, with 1 standard erythema dose (SED)) or to the control group (VD group, n = 37; 5600 International units (IU) cholecalciferol supplementation once a week). The main outcome was well-being, measured by the Cohen-Mansfield Agitation Inventory (CMAI) and the Cornell scale for depression in dementia at 0, 3, and 6 months. Secondary outcomes were QUALIDEM quality of life domains and biochemical parameters of bone homeostasis. Intention-to-treat analysis with linear mixed modeling showed no significant between-group differences on agitation (p = 0.431) or depressive symptoms (p = 0.982). At six months, the UVB group showed less restless/tense behavior compared to the VD group (mean difference of the mean change scores 2.2, 95% CI 0.8 to 3.6; p = 0.003 for group x time interaction) and lower serum 25(OH)D3 concentration (estimated mean difference - 21.9, 95% CI −32.6 to −11.2; p = 0.003 for group difference). The exposure of nursing home residents with dementia to UVB light showed no positive benefits in terms of wellbeing. UVB treatment may have a positive effect on the restless/tense behavior characteristic of advanced dementia but more research is needed to confirm this finding.

Effect of UVB light on vitamin D status in piglets and sows

Piglets are born with very low levels of vitamin D. Feed is the only source of vitamin D for pigs kept indoors, and the levels in feed are restricted by European legislation. We aimed to study the effect of lamps releasing ultraviolet type B (UVB) light on the vitamin D status (serum 25-hydroxyvitamin D) in sows and piglets in a Danish indoor herd.A randomized trial with a parallel group design was initiated with two groups receiving a daily UVB-dose of maximum 0.7 standard erythema dose (SED) or 1 SED, in addition to a control group. The three groups included in the study consisted of 15 sows and their 195 offspring. Blood samples were taken from the piglets and sows on day 1, 12, and 24. Results showed no difference between the groups in serum levels of 25(OH)D3 or vitamin D3 on day 1, with the mean (±SD) for piglets being 0.96 ± 0.26 ng/mL and 0.06 ± 0.04 ng/mL, respectively. For sows, the values were 16 ± 3 ng/mL 25(OH)D3 and 3 ± 0.8 ng/mL vitamin D3 on day 1. A significant difference (p < 0.001) in serum 25(OH)D3 between the groups receiving UVB light and the control group was observed on both day 12 and day 24. On day 24, the piglet control group had 5.5 ± 2 ng/mL 25(OH)D3 and 0.4 ± 0.2 ng/mL vitamin D3. For the UVB groups, the values were 21.6 ± 10. ng/mL 25(OH)D3 and 8.3 ± 2.5 ng/mL vitamin D3 for the 0.7 SED group and 19.5 ± 6.0 ng/mL 25(OH)D3 and 7.6 ± 3.4 ng/mL vitamin D3 for the 1 SED group. For the sows, the values were 25.6 ± 5.5 ng/mL 25(OH)D3 and 6.6 ± 1.2 ng/mL vitamin D3 for the control group, 66.7 ± 13.5 ng/mL 25(OH)D3 and 21.3 ± 2.9 ng/mL vitamin D3 for 0.7 SED group and 67 ± 15 ng/mL 25(OH)D3 and 25 ± 5 ng/mL vitamin D3 for the 1 SED. No significant difference was found between the two UVB groups for either piglets or sows. The use of lamps releasing UVB light is therefore suggested to be an efficient way to improve the vitamin D status of both sows and piglets.

Melanin has a Small Inhibitory Effect on Cutaneous Vitamin D Synthesis: A Comparison of Extreme Phenotypes

Epidemiology suggests that melanin inhibits cutaneous vitamin D3 synthesis by UVR. Laboratory investigations assessing the impact of melanin on vitamin D production have produced contradictory results. We determined the effect of melanin on vitamin D3 photosynthesis in healthy young volunteers (n= 102) of Fitzpatrick skin types II-VI (white to black). Participants, irrespective of skin type, were exposed to the same suberythemal UVR dose, to 85% body surface area, using solar simulated UVR or narrowband UVB (311 nm). This was repeated five times with intervals of 3-4 days between UVR exposures. Blood was taken before, during, and after the irradiation and assessed for serum 25-hydroxyvitamin D3 (25[OH]D3) as a marker of vitamin D3 status. Linear UVR dose-dependent increases in 25(OH)D3 were highly significant (P ≤ 7.7 x 10-11). The ratios of regression slopes of the different skin type groups were compared, and only skin type II was significantly steeper than the other groups. Comparisons between extreme skin types II and VI showed melanin inhibition factors of approximately 1.3-1.4, depending on the UVR source. We conclude that the inhibitory effect of melanin on vitamin D3 synthesis is small, compared with erythema, but that this difference may be sufficient to explain the epidemiological data.

Exposure to solar UV radiation in outdoor construction workers using personal dosimetry

Occupational exposure to solar UV radiation (SUVR), a Group 1 carcinogen according to the IARC classification is at high exposure levels in outdoor construction workers, usually above the suggested occupational limits. Furthermore, there are no regulations related to this exposure in the EU, except for the artificial UVR. Also, the use of the ICNIRP exposure guideline in an outdoor setting poses problems of adequate dose assessment.In this context, the main purpose of the study was to perform direct measurements of the SUVR dose in outdoor workers from the construction sector, using individual SUVR dosimeters (GENESIS-UV system), for a period of 7 months, from April to October, in a prospective, observational study in two groups of 10 outdoor workers in Romania, located at two different geographic sites.In term of cumulative standard erythema dose (SED), our study population of outdoor construction workers received high levels of solar UV radiation, ranging from 165 SED to 453 SED during 7 months of occupational activity, from April to October.Our results, ranging from 1.28 SED (standard erythema dose) per day to 6.4 SED per day pose an alarm signal to the national and European health authorities to take preventive action for outdoor workers, as the ICNIRP suggested limit value of 1.33 SED for mean daily erythemal UV exposure is vastly exceeded.We suggest that personal dosimetry for SUVR, from simple devices to complex systems as GENESIS-UV should be regularly and mandatory used in outdoor workers, similarly to the usage of personal dosimetry in occupational exposure to ionizing radiations, which could be included in European and national legislation to reduce both, the level of exposure and the detrimental effects on outdoor workers’ health.

Dose and time effects of solar‐simulated ultraviolet radiation on the in vivo human skin transcriptome

SummaryBackgroundTerrestrial ultraviolet (UV) radiation causes erythema, oxidative stress, DNA mutations and skin cancer. Skin can adapt to these adverse effects by DNA repair, apoptosis, keratinization and tanning.ObjectivesTo investigate the transcriptional response to fluorescent solar‐simulated radiation (FSSR) in sun‐sensitive human skin in vivo.MethodsSeven healthy male volunteers were exposed to 0, 3 and 6 standard erythemal doses (SED). Skin biopsies were taken at 6 h and 24 h after exposure. Gene and microRNA expression were quantified with next generation sequencing. A set of candidate genes was validated by quantitative polymerase chain reaction (qPCR); and wavelength dependence was examined in other volunteers through microarrays.ResultsThe number of differentially expressed genes increased with FSSR dose and decreased between 6 and 24 h. Six hours after 6 SED, 4071 genes were differentially expressed, but only 16 genes were affected at 24 h after 3 SED. Genes for apoptosis and keratinization were prominent at 6 h, whereas inflammation and immunoregulation genes were predominant at 24 h. Validation by qPCR confirmed the altered expression of nine genes detected under all conditions; genes related to DNA repair and apoptosis; immunity and inflammation; pigmentation; and vitamin D synthesis. In general, candidate genes also responded to UVA1 (340–400 nm) and/or UVB (300 nm), but with variations in wavelength dependence and peak expression time. Only four microRNAs were differentially expressed by FSSR.ConclusionsThe UV radiation doses of this acute study are readily achieved daily during holidays in the sun, suggesting that the skin transcriptional profile of ‘typical’ holiday makers is markedly deregulated. What's already known about this topic? The skin's transcriptional profile underpins its adverse (i.e. inflammation) and adaptive molecular, cellular and clinical responses (i.e. tanning, hyperkeratosis) to solar ultraviolet radiation.Few studies have assessed microRNA and gene expression in vivo in humans, and there is a lack of information on dose, time and waveband effects. What does this study add? Acute doses of fluorescent solar‐simulated radiation (FSSR), of similar magnitude to those received daily in holiday situations, markedly altered the skin's transcriptional profiles.The number of differentially expressed genes was FSSR‐dose‐dependent, reached a peak at 6 h and returned to baseline at 24 h.The initial transcriptional response involved apoptosis and keratinization, followed by inflammation and immune modulation. In these conditions, microRNA expression was less affected than gene expression.

Solar UV Radiation in Saint-Denis, La Réunion and Cape Town, South Africa: 10 years Climatology and Human Exposure Assessment at Altitude

Solar ultraviolet radiation (UVR) monitoring is important since it depends on several atmospheric parameters which are associated with climate change and since excess solar UVR exposure and has significant impacts on human health and wellbeing. The objective of this study was to investigate the trends in solar UVR during a decade (2009–2018) in Saint-Denis, Reunion Island (20.9°S, 55.5°E, 85 m ASL) and Cape Town, South Africa (33.97°S, 18.6°E, 42 m ASL). This comparison was done using total daily erythema exposure as derived from UVR sensors continuously at both sites. Climatology over the 10-year period showed extreme UVR exposure for both sites. Slight changes with opposite trends were found, +3.6% at Saint-Denis and −3.7% at Cape Town. However, these two sites often experience extreme weather conditions thereby making the trend evaluation difficult. Human exposure assessment was performed for hiking activities at two popular high-altitude hiking trails on the Maïdo–Grand Bénare (Reunion) and Table Mountain (Cape Town) with a handheld radiometer. Extreme exposure doses of 64 SED and 40 SED (Standard Erythemal Dose, 1 SED = 100 J.m−2) were recorded, respectively. These high exposure doses highlight the importance of raising public awareness on the risk related to excess UVR exposure at tourist sites, especially those at high altitude.

Occupational Exposure to Solar UV Radiation of a Group of Fishermen Working in the Italian North Adriatic Sea.

Occupational solar radiation exposure is a relevant heath risk in the fishing sector. Our aim was to provide a detailed evaluation of individual UV exposure in three different fishing activities in Italy, with personal UV dosimeters and a simple formula to calculate the fraction of ambient erythemal UV dose received by the workers. The potential individual UV exposure of the fishermen was between 65 and 542 Joules/m2. The percentages of the ambient exposure were estimated between 2.5% and 65.3%. Workers’ UV exposure was mainly influenced by the characteristics of the work activity, the postures adopted, and the type of boats. Overall, our data showed that 43% of the daily measurements could result largely above the occupational limits of 1–1.3 standard erythemal dose (i.e., 100 Joules/m2) per day, in case of exposure of uncovered skin areas. Measurements of individual UV exposure are important not only to assess the risk but also to increase workers’ perception and stimulate the adoption of preventive measures to reduce solar UV risk. Furthermore, the simple method proposed, linking ambient erythemal UV dose to the workers’ exposure, can be a promising tool for a reliable assessment of the UV risk, as time series of environmental UV dose are widely available.