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1.
Article de Anglais | MEDLINE | ID: mdl-31623384

RÉSUMÉ

Seasonality in glucose metabolism has been observed in adult populations; however, little is known of the associations between season and glucose metabolism in children. In this study, we examined whether markers of glucose metabolism (fasting glucose, insulin and HbA1c) varied by season in a paediatric population (6-13 years of age) located in Perth (Western Australia, n = 262) with data categorised by weight. Linear regression was used to analyse the nature of the relationships between mean daily levels of terrestrial ultraviolet radiation (UVR) (prior to the day of the blood test) and measures of glucose metabolism. Fasting blood glucose was significantly lower in autumn compared to spring, for children in combined, normal and obese weight categories. Fasting insulin was significantly lower in autumn and summer compared to winter for individuals of normal weight. HbA1c was significantly higher in summer (compared with winter and spring) in overweight children, which was in the opposite direction to other published findings in adults. In children with obesity, a strong inverse relationship (r = -0.67, p = 0.002) was observed for fasting glucose, and daily terrestrial UVR levels measured in the previous 6 months. Increased safe sun exposure in winter therefore represents a plausible means of reducing fasting blood sugar in children with obesity. However, further studies, using larger paediatric cohorts are required to confirm these relationships.


Sujet(s)
Exposition environnementale/effets indésirables , Jeûne/sang , Insuline/sang , Rayons ultraviolets/effets indésirables , Marqueurs biologiques/sang , Glycémie/métabolisme , Enfant , Femelle , Humains , Mâle , Saisons , Australie occidentale/épidémiologie
2.
Health Phys ; 114(1): 84-90, 2018 01.
Article de Anglais | MEDLINE | ID: mdl-30085971

RÉSUMÉ

The Global Solar UV Index was developed as an easy-to-understand measure of the amount of biologically-effective ambient solar ultraviolet radiation (UVR) at different locations on the earth's surface. Over the past few years, questions have been raised about the global applicability of the UV Index, about the evidence base for exposure risk thresholds and related protective measures, and about whether the overall impact of the UV Index could be improved with modifications. An international workshop was organized by several organizations, including the World Health Organization, to assess if current evidence was sufficiently strong to modify the UV Index and to discuss different ways it might be improved in order to influence sun-protective behavior. While some animal research suggests there may be no threshold effect, the relative importance of sub-erythemal doses of sunlight in causing skin cancer in humans remains unknown. Evidence suggests that regular use of sunscreen can prevent skin cancer and that sunglasses are an effective method of protecting the eyes from solar UVR. The UV Index as a risk communication tool continues to be useful for raising awareness and to support sun-protection behavior. Although there was agreement that guidance on the use of the UV Index could be improved, the workshop participants identified that strong health outcome-based human evidence would be needed as the basis for a revision. For the UV Index to be relevant in as many countries as possible, it should continue to be adapted to suit local conditions.


Sujet(s)
Lumière du soleil/effets indésirables , Rayons ultraviolets , Maladies de l'oeil/prévention et contrôle , Dispositifs de protection des yeux , Humains , Tumeurs radio-induites/prévention et contrôle , Risque , Tumeurs cutanées/étiologie , Tumeurs cutanées/prévention et contrôle , Produits antisolaires
3.
Photochem Photobiol ; 92(1): 208-14, 2016.
Article de Anglais | MEDLINE | ID: mdl-26575187

RÉSUMÉ

This study aimed to compare the validity, reliability and practicality of alternative portable methods for measuring erythemal UVR levels in passive recreation areas in public parks. UVR levels were measured for point in time comparisons between Solarmeter 6.5 handheld meters and time-stamped electronic dosimeters in a large central park in Melbourne, Australia. Observations were made at 20 locations in the park by two research assistants under two conditions: (1) matched shade (2) contrasting shade-no shade. Comparisons were also made with scientific instruments on the UVR monitoring station rooftop and by remotely selecting UV records and forecasts on cloud-free dates of park observations. There was good agreement between the portable UVR instruments in the park setting as confirmed via Bland Altman plots, while the dosimeter appeared less sensitive to change in shade conditions. The rooftop measurements showed that the Solarmeter 6.5 UVR readings were comparable to those of the adjacent rooftop instruments. The practicalities of using the dosimeters and Solarmeters for behavioral studies are discussed. These findings provide a basis for use of the Solarmeter 6.5 to measure changes in UVR levels due to different environmental conditions with relative accuracy for intervention studies in outdoor settings.


Sujet(s)
Électronique , Rayons ultraviolets , Relation dose-effet des rayonnements , Humains , Loisir
4.
Photochem Photobiol ; 91(5): 1237-46, 2015.
Article de Anglais | MEDLINE | ID: mdl-26147793

RÉSUMÉ

Monitoring ambient solar UVR levels provides information on how much there is in both real time and historically. Quality assurance of ambient measurements of solar UVR is critical to ensuring accuracy and stability and this can be achieved by regular intercomparisons of spectral measurement systems with those of other organizations. In October and November of 2013 a solar UVR spectroradiometer from Public Health England (PHE) was brought to Melbourne for a campaign of intercomparisons with a new Bentham spectrometer of Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) and one at the Australian Bureau of Meteorology (BOM), supported by New Zealand's National Institute for Water and Atmosphere (NIWA). Given all three spectroradiometers have calibrations that are traceable to various national standards, the intercomparison provides a chance to determine measurement uncertainties and traceability that support UV measurement networks in Australia, New Zealand and the UK. UV Index measurements from all three systems were compared and ratios determined for clear sky conditions when the scans from each instrument were within 2 min of each other. While wavelengths below 305 nm showed substantial differences between the PHE unit and the two other systems, overall the intercomparison results were encouraging, with mean differences in measured UV Index between the BOM/NIWA and those of PHE and ARPANSA of <0.1% and 7.5%, respectively.


Sujet(s)
Surveillance de l'environnement/instrumentation , Rayons ultraviolets , Australie , Humains
5.
BMC Public Health ; 15: 115, 2015 Feb 10.
Article de Anglais | MEDLINE | ID: mdl-25884724

RÉSUMÉ

BACKGROUND: Adults living in the sunny Australian climate are at high risk of skin cancer, but vitamin D deficiency (defined here as a serum 25-hydroxyvitamin D (25(OH)D) concentration of less than 50 nmol/L) is also common. Vitamin D deficiency may be a risk factor for a range of diseases. However, the optimal strategies to achieve and maintain vitamin D adequacy (sun exposure, vitamin D supplementation or both), and whether sun exposure itself has benefits over and above initiating synthesis of vitamin D, remain unclear. The Sun Exposure and Vitamin D Supplementation (SEDS) Study aims to compare the effectiveness of sun exposure and vitamin D supplementation for the management of vitamin D insufficiency, and to test whether these management strategies differentially affect markers of immune and cardio-metabolic function. METHODS/DESIGN: The SEDS Study is a multi-centre, randomised controlled trial of two different daily doses of vitamin D supplementation, and placebo, in conjunction with guidance on two different patterns of sun exposure. Participants recruited from across Australia are aged 18-64 years and have a recent vitamin D test result showing a serum 25(OH)D level of 40-60 nmol/L. DISCUSSION: This paper discusses the rationale behind the study design, and considers the challenges but necessity of data collection within a non-institutionalised adult population, in order to address the study aims. We also discuss the challenges of participant recruitment and retention, ongoing engagement of referring medical practitioners and address issues of compliance and participant retention. TRIAL REGISTRATION: Australia New Zealand Clinical Trials Registry: ACTRN12613000290796 Registered 14 March 2013.


Sujet(s)
Héliothérapie/méthodes , Carence en vitamine D/thérapie , Vitamine D/analogues et dérivés , Vitamines/administration et posologie , Adolescent , Adulte , Australie/épidémiologie , Climat , Compléments alimentaires , Relation dose-effet des médicaments , Femelle , Humains , Mâle , Adulte d'âge moyen , Nouvelle-Zélande/épidémiologie , Plan de recherche , Facteurs de risque , Saisons , Tumeurs cutanées/étiologie , Lumière du soleil/effets indésirables , Vitamine D/administration et posologie , Jeune adulte
6.
Australas J Dermatol ; 56(4): 275-8, 2015 Nov.
Article de Anglais | MEDLINE | ID: mdl-25496328

RÉSUMÉ

BACKGROUND: Australia has the highest incidence of skin cancer in the world, a preventable disease caused primarily by exposure to ultraviolet radiation (UVR) in sunlight. Health promotion strategies play a significant role in sun protection. OBJECTIVES: To assess the understanding of a population sample as to the time of year that the sun was 'at its most burning' in Melbourne, Australia. METHODS: A cross-sectional study was performed using questionnaires completed at corporate skin checks, conducted on 668 participants during 2011 to 2013. RESULTS: Only a minority (n = 82, 12%) gave the correct theoretical answer; the summer solstice or 21-22 December, while another 38% (n = 254) correctly named December and January as the times when the UVR is actually highest. In all, 18% (n = 122) said February was the month when the temperature is hottest and 170 (25%) either mentioned the period May-August when UVR is negligible in Melbourne or had no idea, including saying 'all year round'. There was no significant difference in this knowledge between different age groups. CONCLUSION: One-quarter of participants did not understand that sunburn was related to high levels of UVR, which occur in summer. Almost one-fifth associated the heat of February with the highest UVR. Understanding these concepts is important for Australians residing in cooler parts of southern Australia, as UVR levels may be high and yet the temperature may be relatively cool. There needs to be more emphasis on UVR in sun awareness campaigns to prompt sun-protective behaviour.


Sujet(s)
Exposition environnementale , Connaissances, attitudes et pratiques en santé , Saisons , Rayons ultraviolets/effets indésirables , Adulte , Études transversales , Femelle , Humains , Mâle , Adulte d'âge moyen , Coup de soleil/étiologie , Coup de soleil/prévention et contrôle , Température , Victoria , Jeune adulte
7.
J Neurol Neurosurg Psychiatry ; 86(2): 200-7, 2015 Feb.
Article de Anglais | MEDLINE | ID: mdl-24790215

RÉSUMÉ

BACKGROUND: Altered reactivity of peripheral blood mononuclear cells (PBMC) and their production of cytokines may affect multiple sclerosis (MS) clinical course. We assessed the relationship of stimulated PBMC-produced IFN-γ, TNF-α, IL-4 and IL-10 in modulating relapse risk using a prospective cohort with established relapsing-remitting MS. METHODS: Cytokine production from PBMCs taken in summer and winter was measured by ELISA. Predictors of cytokines assessed by multilevel mixed-effects linear regression. Predictors of relapse assessed by survival analysis. RESULTS: Increasing IFN-γ was associated with increasing relapse risk, while increasing TNF-α reduced relapse risk after adjusting for IFN-γ. IL-10 and IL4 were not consistently associated with relapse risk. IFN-γ's effects on relapse were greatly attenuated by immunomodulatory therapies, by summer season and by higher serum vitamin D, whereas TNF-α's inverse association with relapse was only present in these circumstances. The TNF-α inverse association with relapse was only present among persons carrying the wild-type of the functional SNP rs1800693 in TNFRSF1A that has been previously associated with MS risk. CONCLUSIONS: We found strong effects of IFN-γ and TNF-α on relapse risk, these differing by immunomodulatory therapy, season, and serum vitamin D, as well as by genotype. These results indicate altered reactivity of immune cells modulate MS disease.


Sujet(s)
Interféron gamma/sang , Agranulocytes/métabolisme , Sclérose en plaques récurrente-rémittente/sang , Facteur de nécrose tumorale alpha/sang , Adulte , Sujet âgé , Femelle , Génotype , Humains , Immunomodulation , Interféron gamma/métabolisme , Interleukine-10/sang , Interleukine-10/métabolisme , Interleukine-4/sang , Interleukine-4/métabolisme , Mâle , Adulte d'âge moyen , Sclérose en plaques récurrente-rémittente/traitement médicamenteux , Sclérose en plaques récurrente-rémittente/génétique , Sclérose en plaques récurrente-rémittente/métabolisme , Polymorphisme de nucléotide simple , Études prospectives , Récepteur au facteur de nécrose tumorale de type I/génétique , Récidive , Facteurs de risque , Saisons , Analyse de survie , Facteur de nécrose tumorale alpha/métabolisme , Vitamine D/sang , Jeune adulte
8.
Arch Osteoporos ; 9: 197, 2014.
Article de Anglais | MEDLINE | ID: mdl-25311734

RÉSUMÉ

UNLABELLED: The aim of this study was to determine the vitamin D response to sunlight ultraviolet radiation in older people. Increases in vitamin D depended on the season of exposure, but the changes were small. Natural sun exposure is not a practical intervention for vitamin D deficiency in this population. PURPOSE: The purpose of this study is to measure the ultraviolet radiation (UVR) exposure of those in residential aged care in an earlier trial of sunlight exposure and to determine its effect on their vitamin D response. METHODS: Attendance data, demographic, clinical and biochemical variables for 248 participants were used for a secondary analysis of a previous cluster randomized trial of sunlight exposure and falls. The ambient solar UV Index data were used to calculate the participants' UVR dose. Multiple linear regression was used to test if UVR exposure over 6 months, as measured by the standard erythemal dose (SED), was a predictor of vitamin D response, controlling for age, gender, BMI, calcium intake, baseline vitamin D and season of exposure. RESULTS: The median 25-hydroxyvitamin D (25OHD) was 32.4 nmol/L at baseline and 34.6 nmol/L at 6 months (p = 0.35). The significant predictors of 25OHD at 6 months were UVR exposures in spring-summer (coefficient = 0.105, 95 % confidence interval (CI) 0.001-0.209, p = 0.05) and autumn-winter (coefficient = 0.056, 95 % CI 0.005-0.107, p = 0.03) and baseline vitamin D (adjusted coefficient = 0.594, 95 % CI 0.465-0.724, p = 0.00). In those starting sunlight sessions in spring, an increase of 1 unit in log SED was associated with 11 % increase in 25OHD. CONCLUSIONS: Natural UVR exposure can increase 25OHD levels in older people in residential care, but depends on the season of exposure. However, due to inadequate sun exposure, 25OHD did not reach optimal levels. Nevertheless, where sun exposure is encouraged in this group, the focus for the start of exposure should be in the months of spring or autumn, as this timing was associated with a vitamin D response.


Sujet(s)
Lumière du soleil , Carence en vitamine D/prévention et contrôle , Vitamine D/analogues et dérivés , Sujet âgé de 80 ans ou plus , Calcium , Femelle , Humains , Mâle , Radiométrie , Vitamine D/sang
9.
Photochem Photobiol ; 90(6): 1455-61, 2014.
Article de Anglais | MEDLINE | ID: mdl-25244558

RÉSUMÉ

Vitamin D deficiency is more common in Northeast-Asian immigrants to western countries than in the local population; prevalence equalizes as immigrants adopt the host country's culture. In a community-based study of 100 Northeast-Asian immigrants in Canberra, Australia, we examined predictors of vitamin D status, its association with indicators of acculturation (English language use; time since migration) and mediators of that association. Participants completed a sun and physical activity diary and wore an electronic ultraviolet radiation (UVR) dosimeter for 7 days. Skin colour was measured by reflectance spectrophotometry. Serum concentrations of 25-hydroxyvitamin D (25(OH)D) and cardio-metabolic biomarkers were measured on fasting blood. In a multiple linear regression model, predictors for 25(OH)D concentration were season of blood collection, vitamin D supplementation, UVR exposure, body mass index, physical activity and having private health insurance (R(2) = 0.57). Greater acculturation was associated with lower risk of vitamin D deficiency (de-seasonalized 25(OH)D level <50 nmol L(-1)) (Adjusted Odds Ratio (AOR): 0.22 [95%CI 0.04-0.96]); this association was statistically mediated by physical activity and time outdoors. Vitamin D deficiency was associated with higher total cholesterol levels (>5.0 mmol L(-1)) (AOR: 7.48 [95%CI 1.51-37.0]). Targeted public health approaches are required to manage the high prevalence of vitamin D deficiency in migrants retaining a traditional lifestyle.


Sujet(s)
Lumière du soleil , Vitamine D/biosynthèse , Adolescent , Adulte , Asie/ethnologie , Australie , Exposition environnementale , Femelle , Humains , Mâle , Adulte d'âge moyen
10.
Photochem Photobiol ; 89(4): 968-73, 2013.
Article de Anglais | MEDLINE | ID: mdl-23565839

RÉSUMÉ

This study assessed the UVR protection provided by shade structures over toddler pools at swimming pool centers in Melbourne. The UVR protection was measured using a combination of UV sensitive polysulfone film to derive an average value during the middle of the day (1-2 P.M.) and handheld UV meters to derive the time variability in UV protection between 11 A.M. and 3 P.M. The amount of UVR protection provided by the shade structures depended upon a number of factors such as location, size, and materials used, but generally ranged from a protection factor (PF) of 2 to ~ 16. The higher PFs were generally for larger structures or where the shade had other structures nearby. The handheld UV meter measurements showed the UV protection varied with position under the shade structure as well as with time of day. While provision of shade structures is becoming more widespread around Australia, improving the shade availability at the pool centers overall, the application of recommendations regarding the provision of shade has been followed to a varying degree by many of the pools visited in this study. In many cases, continued further improvements can be made to provide more adequate protection and further reduce UV exposures.


Sujet(s)
Lumière du soleil/effets indésirables , Piscines , Australie , Obscurité , Humains , Nourrisson , Saisons , Rayons ultraviolets
11.
Photochem Photobiol ; 89(4): 984-94, 2013.
Article de Anglais | MEDLINE | ID: mdl-23550943

RÉSUMÉ

During August 2011 stratospheric ozone over much of Southern Australia dropped to very low levels (approximately 265 Dobson Units) for over a week above major population centers. The weather during this low ozone period was mostly clear and sunny, resulting in measured solar ultraviolet radiation (UVR) levels up to 40% higher than normal, with UV Index > 3 despite being winter. Satellite ozone measurements and meteorological assimilated data indicate that the event was likely due in large part to the anomalous southward movement over Australia of ozone-poor air in the lower stratosphere originating from tropical latitudes. At the time, a study measuring the UVR exposures of outdoor workers in Victoria was underway and a number of the workers recorded substantial UVR exposures and were sunburnt. Given the cities and populations involved (approximately 10 million people), it is likely that many people could have been exposed to anomalously high levels of solar UVR for that time of year, with resultant higher UVR exposures and sunburns to unacclimatized skin (often a problem transitioning from low winter to higher spring UVR levels). Reporting procedures have been modified to utilize ozone forecasts to warn the public of anomalously high UVR levels in the future.


Sujet(s)
Ozone , Lumière du soleil , Rayons ultraviolets , Atmosphère , Australie , Surveillance de l'environnement , Saisons , Coup de soleil/étiologie , Facteurs temps
12.
Photochem Photobiol ; 89(1): 219-26, 2013.
Article de Anglais | MEDLINE | ID: mdl-22891914

RÉSUMÉ

Self-reported sun exposure is commonly used in research, but how well this represents actual sun exposure is poorly understood. From February to July 2011, a volunteer sample (n = 47) of older adults (≥45 years) in Canberra, Australia, answered brief questions on time outdoors (weekdays and weekends) and natural skin color. They subsequently maintained a sun diary and wore an ultraviolet radiation (UVR) digital dosimeter for 7 days. Melanin density was estimated using reflectance spectrophotometry; lifetime sun damage was assessed using silicone casts of the back of the hand; and serum 25-hydroxyvitamin D (25(OH)D) concentration was assayed. Questionnaire-reported time outdoors correlated significantly with diary-recorded time outdoors (Spearman correlation r(s) = 0.66; 95% CI 0.46, 0.80; P < 0.001) and UVR dosimeter dose (r(s ) = 0.46; 95% CI 0.18, 0.68; P = 0.003), but not 25(OH)D concentration (r(s) = 0.24; 95% CI -0.05, 0.50; P = 0.10). Questionnaire-reported untanned skin color correlated significantly with measured melanin density at the inner upper arm (r(s) = 0.49; 95% CI 0.24, 0.68; P < 0.001). In a multiple linear regression model, statistically significant predictors of 25(OH)D concentration were self-reported frequency of physical activity, skin color and recent osteoporosis treatment (R(2) = 0.54). In this study, brief questionnaire items provided valid rankings of sun exposure and skin color, and enabled the development of a predictive model for 25(OH)D concentration.


Sujet(s)
Ostéoporose/sang , Radiométrie/instrumentation , Lumière du soleil , Enquêtes et questionnaires/normes , Vitamine D/analogues et dérivés , Sujet âgé , Agents de maintien de la densité osseuse/usage thérapeutique , Femelle , Humains , Modèles linéaires , Mâle , Mélanines/analyse , Adulte d'âge moyen , Ostéoporose/traitement médicamenteux , Dose de rayonnement , Pigmentation de la peau/effets des radiations , Spectrophotométrie , Facteurs temps , Vitamine D/sang
13.
Photochem Photobiol ; 87(1): 184-90, 2011.
Article de Anglais | MEDLINE | ID: mdl-21091485

RÉSUMÉ

To assist in the development of the 2008 Australian/New Zealand standard on solaria and related regulations, Australian Radiation Protection and Nuclear Safety Agency scientists visited a number of tanning establishments during 2008 to measure the intensity and spectral distribution of the ultraviolet radiation (UVR) emissions from a range of solaria. The 2002 Australian/New Zealand Standard "Solaria for cosmetic purposes" (AS/NZS 2635) allowed a maximum UVR output from solaria of UV Index 60, a compromise between the solarium industry who wanted no upper limit and the health agencies who wanted to limit intensity. Of the 20 solaria examined in detail, only one had emissions of intensity less than UV Index 12, typical of mid-latitude summer sunlight, 15 units emitted more than UV Index 20, while three units emitted at intensities above UV Index 36, the maximum allowed by the new standard, AS/NZS 2635 (2008) and would thus not comply. UVA emissions ranged from 98W·m(-2) up to a maximum of 438W·m(-2) , more than six times the UVA content of mid-latitude summer sunshine. The results indicate that solaria users in Australia have access to solaria that are high intensity units with both significantly higher UVB and UVA emissions than sunlight, with implications for resultant adverse health effects.


Sujet(s)
Rayons ultraviolets , Australie , Études de cohortes , Relation dose-effet des rayonnements , Humains
14.
Cancer Epidemiol Biomarkers Prev ; 19(12): 3005-12, 2010 Dec.
Article de Anglais | MEDLINE | ID: mdl-20940277

RÉSUMÉ

BACKGROUND: Reliance on verbal self-report of solar exposure in skin cancer prevention and epidemiologic studies may be problematic if self-report data are not valid due to systematic errors in recall, social desirability bias, or other reasons. METHODS: This study examines the validity of self-reports of exposure to ultraviolet radiation (UVR) compared to objectively measured exposure among children and adults in outdoor recreation settings in 4 regions of the United States. Objective UVR exposures of 515 participants were measured using polysulfone film badge UVR dosimeters on 2 days. The same subjects provided self-reported UVR exposure data on surveys and 4-day sun exposure diaries, for comparison to their objectively measured exposure. RESULTS: Dosimeter data showed that lifeguards had the greatest UVR exposure (24.5% of weekday ambient UVR), children the next highest exposures (10.3% ambient weekday UVR), and parents had the lowest (6.6% ambient weekday UVR). Similar patterns were observed in self-report data. Correlations between diary reports and dosimeter findings were fair to good and were highest for lifeguards (r = 0.38-0.57), followed by parents (r = 0.28-0.29) and children (r = 0.18-0.34). Correlations between survey and diary measures were moderate to good for lifeguards (r = 0.20-0.54) and children (r = 0.35-0.53). CONCLUSIONS: This is the largest study of its kind to date, and supports the utility of self-report measures of solar UVR exposure. IMPACT: Overall, self-reports of sun exposure produce valid measures of UVR exposure among parents, children, and lifeguards who work outdoors.


Sujet(s)
Dosimétrie photographique , Autorapport , Lumière du soleil , Rayons ultraviolets , Adolescent , Adulte , Enfant , Enfant d'âge préscolaire , Femelle , Humains , Mâle , Parents , Reproductibilité des résultats , Poids et mesures , Jeune adulte
15.
Ann Neurol ; 68(2): 193-203, 2010 Aug.
Article de Anglais | MEDLINE | ID: mdl-20695012

RÉSUMÉ

OBJECTIVE: A protective association between higher vitamin D levels and the onset of multiple sclerosis (MS) has been demonstrated; however, its role in modulating MS clinical course has been little studied. We investigated whether higher levels of serum 25-hydroxyvitamin D (25-OH-D) were associated with a lower risk of relapses in people with MS. METHODS: We conducted a prospective cohort study of 145 participants with relapsing-remitting MS from 2002 to 2005. Serum 25-OH-D levels were measured biannually, and the hazard of relapse was assessed using survival analysis. RESULTS: There was an inverse linear relationship between 25-OH-D levels and the hazard of relapse over the subsequent 6 months, with hazard ratio (HR) 0.91 (95% confidence interval [CI]: 0.85-0.97) per 10 nmol/l increase in 25-OH-D level (p = 0.006). When variation due to timing of blood collection was removed by estimating 25-OH-D at the start of each season, this association persisted, with HR 0.90 (95% CI, 0.83-0.98) per 10 nmol/l increase (p = 0.016). Taking into account the biological half-life of 25-OH-D, we estimated 25-OH-D at monthly intervals, resulting in a slightly enhanced association, with HR 0.88 (95% CI, 0.82-0.95) per 10 nmol/l increase (p = 0.001). Adjusting for potential confounders did not alter these findings. INTERPRETATION: In this prospective population-based cohort study, in a cohort largely on immunomodulatory therapy, higher 25-OH-D levels were associated with a reduced hazard of relapse. This occurred in a dose-dependent linear fashion, with each 10 nmol/l increase in 25-OH-D resulting in up to a 12% reduction in risk of relapse. Clinically, raising 25-OH-D levels by 50 nmol/l could halve the hazard of a relapse.


Sujet(s)
Sclérose en plaques récurrente-rémittente/sang , Sclérose en plaques récurrente-rémittente/épidémiologie , Vitamine D/analogues et dérivés , Adulte , Sujet âgé , Marqueurs biologiques/analyse , Marqueurs biologiques/sang , Femelle , Humains , Mâle , Adulte d'âge moyen , Sclérose en plaques récurrente-rémittente/diagnostic , Études prospectives , Récidive , Appréciation des risques , Facteurs de risque , Vitamine D/sang , Jeune adulte
16.
Photochem Photobiol ; 86(2): 445-8, 2010.
Article de Anglais | MEDLINE | ID: mdl-20113430

RÉSUMÉ

Generating accurate population-specific public health messages regarding sun protection requires knowledge about seasonal variation in sun exposure in different environments. To address this issue for a subtropical area of Australia, we used polysulphone badges to measure UVR for the township of Nambour (26 degrees latitude) and personal UVR exposure among Nambour residents who were taking part in a skin cancer prevention trial. Badges were worn by participants for two winter and two summer days. The ambient UVR was approximately three times as high in summer as in winter. However, participants received more than twice the proportion of available UVR in winter as in summer (6.5%vs 2.7%, P < 0.05), resulting in an average ratio of summer to winter personal UVR exposure of 1.35. The average absolute difference in daily dose between summer and winter was only one-seventh of a minimal erythemal dose. Extrapolating from our data, we estimate that ca. 42% of the total exposure received in the 6 months of winter (June-August) and summer (December-February) is received during the three winter months. Our data show that in Queensland a substantial proportion of people's annual UVR dose is obtained in winter, underscoring the need for dissemination of sun protection messages throughout the year in subtropical and tropical climates.


Sujet(s)
Exposition environnementale/statistiques et données numériques , Saisons , Lumière du soleil , Adulte , Australie , Humains , Dose de rayonnement , Tumeurs cutanées/prévention et contrôle , Rayons ultraviolets , Jeune adulte
17.
Photochem Photobiol ; 85(6): 1485-90, 2009.
Article de Anglais | MEDLINE | ID: mdl-19706145

RÉSUMÉ

A study to assess the potential exposure to solar UV radiation of expeditioners on Australian Antarctic resupply voyages was carried out over the Austral summers of 2004/2005 to 2006/2007. Subjects wore UVR-sensitive polysulphone (PS) badges on the chest for the duration of their working day, which generally ranged from 5 to 10 h, but could be as long as 14 h. Measurements were carried out during unloading of two vessels while they were at the three Australian Antarctic stations. The subjects wore standard Australian Antarctic Division clothing assemblages, although the face and hands and in some cases more of the limbs were uncovered and subjected to exposure to UVR. The badges worn by the subjects received exposures ranging from 0.2 to 18 standard erythemal doses (SEDs), with a median of 3.2 SEDs. However, comparison with occupational exposure limits showed that more than 80% of the subjects' PS badges received UVR exposures in excess of the limits while 31% received more than five times the limits. Despite sun protection being provided more than 70% of the workers reported mild erythema.


Sujet(s)
Exposition professionnelle , Contrôle des radiations , Rayons ultraviolets , Régions antarctiques , Australie , Érythème , Humains
18.
Am J Ind Med ; 52(8): 645-53, 2009 Aug.
Article de Anglais | MEDLINE | ID: mdl-19572325

RÉSUMÉ

BACKGROUND: The aim of this study was to measure ultraviolet radiation (UVR) exposures of lifeguards in pool settings and evaluate their personal UVR protective practices. METHODS: Lifeguards (n = 168) wore UVR sensitive polysulfone (PS) film badges in wrist bracelets on 2 days and completed a survey and diary covering sun protection use. Analyses were used to describe sun exposure and sun protection practices, to compare UVR exposure across locations, and to compare findings with recommended threshold limits for occupational exposure. RESULTS: The measured UVR exposures varied with location, ranging from high median UVR exposures of 6.2 standard erythemal doses (SEDs) to the lowest median of 1.7 SEDs. More than 74% of the lifeguards' PS badges showed UVR above recommended threshold limits for occupational exposure. Thirty-nine percent received more than four times the limit and 65% of cases were sufficient to induce sunburn. The most common protective behaviors were wearing sunglasses and using sunscreen, but sun protection was often inadequate. CONCLUSIONS: At-risk individuals were exposed to high levels of UVR in excess of occupational limits and though appropriate types of sun protection were used, it was not used consistently and more than 50% of lifeguards reported being sunburnt at least twice during the previous year.


Sujet(s)
Exposition professionnelle/effets indésirables , Système solaire , Coup de soleil/épidémiologie , Produits antisolaires , Piscines , Natation , Rayons ultraviolets/effets indésirables , Adulte , Collecte de données , Femelle , Humains , Mâle , Santé au travail , Radioprotecteurs , Prise de risque , Coup de soleil/prévention et contrôle , États-Unis/épidémiologie
19.
J Am Acad Dermatol ; 60(5): 739-44, 2009 May.
Article de Anglais | MEDLINE | ID: mdl-19278750

RÉSUMÉ

BACKGROUND: Few studies have reported the accuracy of measures used to assess sun-protection practices. Valid measures are critical to the internal validity and use of skin cancer control research. OBJECTIVES: We sought to validate self-reported covering-up practices of pool-goers. METHODS: A total of 162 lifeguards and 201 parent/child pairs from 16 pools in 4 metropolitan regions in the United States completed a survey and a 4-day sun-habits diary. Observations of sun-protective behaviors were conducted on two occasions. RESULTS: Agreement between observations and diaries ranged from slight to substantial, with most values in the fair to moderate range. Highest agreement was observed for parent hat use (kappa = 0.58-0.70). There was no systematic pattern of over- or under-reporting among the 3 study groups. LIMITATIONS: Potential reactivity and a relatively affluent sample are limitations. CONCLUSION: There was little over-reporting and no systematic bias, which increases confidence in reliance on verbal reports of these behaviors in surveys and intervention research.


Sujet(s)
Comportement en matière de santé , Tumeurs cutanées/prévention et contrôle , Coup de soleil/prévention et contrôle , Enfant , Enfant d'âge préscolaire , Collecte de données , Exposition environnementale/prévention et contrôle , Humains , Parents , Lumière du soleil/effets indésirables , Piscines , États-Unis
20.
Health Policy ; 89(3): 303-11, 2009 Mar.
Article de Anglais | MEDLINE | ID: mdl-18760857

RÉSUMÉ

OBJECTIVE: In Australia there is growing concern about the expanding solarium industry, and the additive effect of persons seeking exposure to artificial ultraviolet radiation (UVR) against already intense background levels of solar UVR. We estimated the numbers of potential skin cancers prevented through regulation of solaria and the associated cost-savings to the Federal Government. METHODS: A lifetime decision-analytic model was created using relative risk estimates based on a meta-analysis of the literature assessing the link between skin cancer risk and solarium use. The costs were limited to those incurred by Medicare Australia, for the medical care of individuals treated for skin cancer. RESULTS: With stricter regulations, we estimated between 18 and 31 melanomas, 200-251 squamous cell carcinomas and associated costs of $AU 256,054 would be avoided per 100,000 persons. Our base findings were sensitive to estimates for prevalence of use, skin cancer risk and discounting rates. CONCLUSIONS: Continued growth in the Australian solarium industry is likely to inflate the already substantial skin cancer burden. Subject to some limitations, our study indicates that by successfully enforcing solarium regulations to prohibit use by minors and by those with fair skin colour, the Federal Government could expect favourable cost and health benefits.


Sujet(s)
Réglementation gouvernementale , Tumeurs cutanées/prévention et contrôle , Bain de soleil/législation et jurisprudence , Adolescent , Australie , Commerce/législation et jurisprudence , Économies , Humains , Chaines de Markov , Rayons ultraviolets/effets indésirables , Jeune adulte
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