Ola Engelsen

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The dangers of overexposure to sunlight have been well publicized, but less attention has been given to an acknowledged benefit of exposure to UV radiation; that being the cutaneous synthesis of vitamin D3. Here we define a standard vitamin D dose on the basis of recently recommended requirements for vitamin D that take account of its risk reduction role in(More)
OBJECTIVE To determine the vitamin D status of middle-aged women living in the Norwegian arctic and its relationship with vitamin D intake and exposure to ultraviolet (UV) radiation. DESIGN Cross-sectional study. SUBJECTS AND SETTING This study is based on measurements of 25-hydroxyvitamin D (25(OH)D) levels in a sub-sample of the Norwegian component of(More)
BACKGROUND Inadequate sun exposure and dietary vitamin D intake can result in vitamin D insufficiency. However, limited data are available on actual vitamin D status and predictors in healthy individuals in different regions and by season. METHODS We compared vitamin D status [25-hydroxyvitamin D; 25(OH)D] in people < 60 years of age using data from(More)
Vitamin D production in human skin occurs only when incident UV radiation exceeds a certain threshold. From simulations of UV irradiances worldwide and throughout the year, we have studied the dependency of the extent and duration of cutaneous vitamin D production in terms of latitude, time, total ozone, clouds, aerosols, surface reflectivity and altitude.(More)
The main purpose with this study was to assess the seasonal variation in measured UV-radiation and its impact on vitamin D status throughout one year in subjects living at high latitude. Blood samples drawn from 60 volunteers (44 women, 16 men) living at Andenes (69 degrees N), Norway, were collected throughout one year, at two-month intervals. The blood(More)
BACKGROUND The relationship between oral vitamin D supplementation and cutaneous photosynthesis is not well understood. OBJECTIVE We sought to provide estimates of the equivalency of vitamin D production from natural sun exposure versus oral supplementation. METHODS Using the FastRT simulation tool, we determined sun exposure times needed to achieve(More)
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(More)
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(More)
Exposure to sunlight is a major source of vitamin D for most people yet public health advice focuses overwhelmingly on avoiding exposure of unprotected skin because of the risks oferythema and skin cancer. We have calculated the exposure required to gain a number of proposed oral-equivalent doses of vitamin D, as functions of latitude, season, skin type and(More)