Kåre Edvardsen

Vitamin D-effective solar UV radiation, dietary vitamin D and breast cancer risk

Vitamin D is well known for its important role in calcium and phosphor homeostasis. Recent research suggests that vitamin D also prevent some type of cancers. We studied solar vitamin D effective UV radiation (VD dose), dietary vitamin D, sun‐seeking holidays, use of solarium, frequency of sunburn and breast cancer risk in a large population‐based cohort study. A total of 41,811 women from the prospective Norwegian Women and Cancer Study, aged 40–70 years at baseline, were followed from 1997/1998 to 2007. Dietary vitamin D intake was calculated at baseline. Information on historical VD dose was used as a proxy for cutaneously obtained vitamin D status. Cox proportional hazards model was used. We adjusted for age, height, BMI, baseline menopausal status, use of hormone replacement therapy, use of oral contraception, alcohol, mothers history of breast cancer, mammography and parity. During 8.5 years of follow‐up, 948 new cases of breast cancer were registered using data from the Norwegian Cancer Registry. We found no significant associations between VD dose, or vitamin D intake, or sun‐seeking holidays, or use of solarium, or frequency of sunburn, and breast cancer risk. Relative risks (95% confidence intervals) for highest versus lowest category were 1.17 (0.95–1.44), 0.95 (0.75–1.21), 1.07 (0.87–1.32), 0.93 (0.76–1.14) and 1.10 (0.89–1.36), respectively. Our results do not support an association between vitamin D status, and breast cancer risk.

The solar UV radiation level needed for cutaneous production of vitamin D3 in the face. A study conducted among subjects living at a high latitude (68° N)

Populations at high latitudes experience several winter months with insufficient UV solar radiation to induce a significant cutaneous production of vitamin D. This unique study was designed to pursue an in vivo threshold of UV radiation needed for cutaneous production of vitamin D to take place if only the face was exposed to UV radiation. The vitamin D status were measured by analyzing blood samples weekly from a study group of 15 subjects over a period of 2 months during late winter, when UV radiation can be expected to increase substantially from rising solar elevations. Statistical analysis showed no significant positive association between the mean UV radiation dose and the mean 25(OH)D (25-hydroxy vitamin D) for the group. On an individual basis, however, we found indications that subjects with very low initial concentration of 25(OH)D (<30 nmol l(-1)) seemed to respond to UV radiation as early as in the beginning of March. For other individuals diet seemed to be the dominant controlling factor for 25(OH)D levels.

Prevalence and trends of sunscreen use and sunburn among Norwegian women

Sunscreen is recommended to prevent sunburn and skin cancer.

Atmospheric monitoring at the Norwegian Antarctic station Troll: measurement programme and first results

The Troll Atmospheric Station in Antarctica (72°01′S, 2°32′E, 1309 m a.s.l.) was established and put into operation in early 2007. The main foci of the measurement programme are pollution and aerosols in the transition zone between the coastal zone and the inland ice plateau, complementing existing observation programmes along the Antarctic coast and on the Antarctic Plateau. After one year of operation, the monitoring programme is fully operative, and a comprehensive set of data is being analysed. As far as comparable data are available, there is satisfactory agreement between previous and new data. Both aerosol data and measurements of pollution indicate the episodic influence of coastal air masses throughout the year. Background values of medium long-lived pollutants such as CO, O3 and Hg are up to 50% lower than at corresponding Arctic sites (depending on the season), but are still significant. Total ozone and UV doses manifest the recurring Antarctic stratospheric ozone hole, which was moderately severe, but very persistent in 2007. Specific episodes of elevated aerosol concentration and mercury activation are currently under detailed investigation, and will be published separately.

Quality assurance of solar UV irradiance in the Arctic.

The first Arctic intercomparison of three solar ultraviolet (UV) spectroradiometers and two multifilter radiometers was held in May and June 2009 at Ny-Alesund, Svalbard, Norway. The transportable reference spectroradiometer QASUME acted as reference instrument for this intercomparison. The measurement period extended over eleven days, comprising clear sky and overcast weather conditions. Due to the high latitude, measurements could be performed throughout the day during this period. The intercomparison demonstrated that the solar UV measurements from all instruments agreed to within +/-15% during the whole measurement period, while the spectroradiometer from the Alfred-Wegener Institute agreed to better than +/-5%. This intercomparison has demonstrated that solar UV measurements can be performed reliably in the high-latitude Arctic environment with uncertainties comparable to mid-latitude sites.

Duration of vitamin D synthesis from weather model data for use in prospective epidemiological studies

In order to investigate the influence of solar radiation on vitamin D status and its association with different health outcomes in population based studies, appropriate estimates of the subjects’ UV radiation exposure are needed. This unique study describes a method that estimates the daily number of vitamin D effective hours (VD-hours) at arbitrary ground locations throughout the period 1957–2002. The method is particularly suited for large-scale prospective epidemiological studies with questionnaire-based information on sun exposure, and where blood measures of vitamin D status are not available. The model takes total cloud cover fraction and total ozone column at noon as input from the ERA-40 data series (i.e. the 40 + year European Centre for Medium-Range Weather Forecasts Re-Analysis archive). By comparing the model results against high accuracy measurements at two different locations in Norway, we found the method for estimating the number of VD-hours to be accurate within 2.5 ± 7% or better for moderate solar zenith angles (< 65°). For higher solar zenith angles (> 65°) the results are more variable, but the contribution to a population’s vitamin D level from solar radiation when the sun is this low in the sky is rather small. The program code to compute VD-hours from ERA–40 files is written in Perl (v 5.8.7) and may be obtained free of charge by contacting corresponding author.

Review of marine icing and anti-/de-icing systems

ABSTRACT The aim of this work is to review the phenomenon of icing in marine operations. The focus is on two main sources of icing, namely atmospheric and sea spray. The literature reveals that sea spray icing is the main contributor to marine icing. This work discusses the available ice accretion prediction models on ships and offshore structures. It also reviews the anti-/de-icing technologies that can be implemented on ships operating in cold climate regions. The significance of ice detection is acknowledged, and a brief review of various ice detection technologies is provided.

Determination of Thermal Properties of Fresh Water and Sea Water Ice using Multiphysics Analysis

The work reported in this paper is funded by the Norges forskningsrad, project no. 195153/160 in collaboration with Faroe Petroleum.

Multiphysics Simulation of Infrared Signature of an Ice Cube

Poster presented at The International Conference of Multiphysics, 10.12.15 - 11.12.15, London

Stratospheric ozone during the arctic winter: Brewer measurements in Ny-Ålesund

To restrict the human impact on the environment, many preventive actions have been adopted in recent decades e.g. the Vienna Convention (1985) and the Montreal Protocol (1987). So monitoring of the atmosphere assumes the important purpose to check the effectiveness of mitigation strategies. The studies on stratospheric ozone are relevant because of its filtering action for UV and its high sensitivity to CFC. During the past 20 years the trend of ozone depletion has been strongly negative, particularly in Polar Regions. Recently weak signals indicate that a recovery has started, even if to disguise anthropogenic impact from natural trend is difficult. So studies on stratospheric ozone during the polar night are important to understand the chemistry involved. This paper shows the results of a first polar winter campaign (September 2007 to March 2008) by Brewer spectrophotometer in Ny-Alesund, Norway, using solar UV reflected by the Moon. TOMS, MLS-AURA and SCIAMACHY data are also shown.