Non-Melanoma Skin Cancer: determining whether the Beagley-Gibson system of scoring photodamage is a useful measure of risk within an age homogonous population.
INTRODUCTION
Ultraviolet radiation (UVR) is an extrinsic factor that can lead to several adverse health outcomes.1-6 Health affected by UVR exposure is measurable in histopathology,7 however it is not always feasible to use histopathology in epidemiological studies.2,8-12 Since it is known that UVR causes photodamage in the skin and is measurable according to the Beagley-Gibson scoring system, it may prove useful as a surrogate non-invasive measure of UVR exposure. 9,10,13 The aim of this study is to determine whether the Beagley-Gibson scoring system is a sensitive measure of risk in an age homogonous group, or whether further refinement of the scoring system is required.
ULTRAVIOLET RADIATION AND DISEASE
The primary source of ultraviolet radiation (UVR) is the sun. 14-17 Other sources include ultraviolet emitting lamps in tanning salons and to treat psoriasis and jaundice. UVR is divided into three categories: ultraviolet A (UVA) radiation, ultraviolet B (UVB) radiation and ultraviolet C (UVC) radiation. UVB radiation is considered more carcinogenic than UVA radiation, and the cause of most sunburns.4,18 The ozone layer prevents some UVR from passing through to the earth’s surface. Most UVA radiation reaches the earth’s surface; only some of UVB radiation and almost no UVC radiation does. 18 However, with recent environmental changes, there is concern that more UVB radiation is passing through the ozone layer.5,19-22
Environmental conditions, including the angle of the sun, clouds, dust and haze also alter the intensity and type of UVR reaching the earth’s surface. High altitudes and low latitudes have higher UVR intensity because there is less air mass for UVR to pass through.23-26 A UVR Index was developed as a guideline to inform the public about daily UVR intensity at a particular time...