Βιώματα και αντιδράσεις του πληθυσμού έναντι της ηλιακής ακτινοβολίας: ωφέλειες, βλάβες και προστασία του δέρματος: τυχαιοποιημένη έρευνα

Abstract

Introduction Apart from its beneficial effects, the sun has serious negative consequences, mostly resulting from excessive exposure to ultraviolet radiation. Short-term consequences include acute solar burn and aggravation of photosensitive diseases, while long-term consequences include photo-carcinogenesis and photo- aging. Skin cancer is the most common type of cancer in humans. Genetic, phenotypic and environmental factors, most importantly ultraviolet radiation, play a pivotal pathogenetic part. During the last decades, a dramatic increase in the incidence of both malignant melanoma and non-melanoma skin cancer has been observed worldwide. Climatic changes, the depletion of the stratospheric ozon and the fashion of sun tanning have all contributed significantly to this increase. Following the international trends, a respective rise in the incidence of skin cancer has been reported in Greece. Greece is privileged with a warm and sunny climate. Most of the population is exposed intensely to solar radiation during occupational or recreational activities, although the prevalent darker skin phototypes act protectively. Skin cancer is subjected to an effective primary prevention. The cornerstone for the prevention of skin cancer is photo-protection. The backbone of any preventive strategy is the education of the population, especially of the high risk groups. In the Western World, particularly in countries with the highest incidence of skin cancer, such as Australia, a lot of effort has been made and several measures have been taken for the prevention of skin cancer. In Greece, during the past two decades similar initiatives have been taken, mostly guided by the Hellenic Society of Dermatology and Venereology. In order to design and organize such preventive campaigns for skin cancer, it is a prerequisite to record the knowledge, the attitudes and behaviours of the population regarding sun exposure and its effects on the skin and photoprotection. Material and Methods The study was conducted by the 2nd Department of Dermatology and Venereology of the National University of Athens Medical School. Data was collected from unselected adult subjects attending the General University Hospital "Attikon" and the 6th IKA Hospital during a 2-year period (September 2006 - March 2009). The participants, after they had given the informed consent, completed a standardized questionnaire that included 30 multiple choice questions. Fifteen questions assessed participants' knowledge about the effects of solar radiation on the skin and the methods of sun protection, while 7 questions evaluated risk behaviours regarding sun exposure. Based on the number of correct answers a "knowledge index" and a "risk behaviour index" were calculated for its participant. On the basis of these indexes, subjects were categorized into low, medium and high level of knowledge groups, as well as into low, medium and high risk behaviour groups. Statistical analysis involved the statistical program SPSS 13.0. Statistical significance was set at the level of 0.05. In order to control type I statistical error Bonferroni's correction was used. For the knowledge index and the risk behaviour index, the mean value and standard deviation were estimated. For the comparison of ratios the X2 test was used. For the comparison of the knowledge index and the risk behaviour index between two or more groups the Student's t test and the ANOVA test were used. Results We recruited 4000 adult subjects, of whom 3680 completed the questionnaire. There were 1632 males (44.3%) and 2048 (55.7%) females. Of them 1616 (44,1%) were young adults (18-39 years), 1616 (44,1%) were middle-aged and 432 (11,8%) were elderly (>60 years). There were 208 (5.7%) skin phototype I persons, 576 (15.7%) skin phototype II, 2272 (61.7%) skin phototype III and 624 (17.0 %) skin phototype IV. Based on the calculated knowledge index, 1248 persons (33.9%) had a low level of knowledge, 2048 persons (56.1%) had a medium level of knowledge and 368 (10.0%) had a high level of knowledge. As far as risk behaviour is concerned, as assessed by the risk behaviour index, 1696 (46.1%) reported a low risk behaviour, 1840 (50,0%) a medium risk behaviour and 144 (3,9%) a high risk behaviour. Statistical analysis showed no correlation between the level of knowledge and the level of risk behaviour (Pearson's correlation factor=0.016, p=0.321). No correlation was found between the knowledge index or the risk behaviour index and various demographic parameters. Discussion As our results indicate, a very high percentage (90%) of the population surveyed had a low or a medium level of sun-related knowledge, while 54% exhibited a medium risk or a high risk behaviour. In accordance with the international literature, no correlation was found between the level of sun knowledge and the level of risk of sun behaviour. Males reported higher occupational and recreational sun exposure than women. Women are more frequent users of sunscreens and young people are more familiar with their proper use. The most common reason (70%) for not using a sunscreen was the desire for a sun tan. Two thirds of the participants still consider a sun tan as a sign of beauty and health. Sunbathing is more popular among young and middle aged persons regardless of sex. Men had a history of sunburn during childhood or adolescence more often than women. Younger individuals and women scored higher in several question regarding sun awareness. Most of the participants consider sun avoidance as the most important photoprotective measure, but failed to recognize the importance of a combination of measures that include protective clothing, as well as the proper use of sunscreens. A percentage as high as 84.3% use the sunscreen only at the beach. Only 14.8% knew what the sun protection factor (SPF) means. Surprisingly, more than 70% knew the acute and chronic effects of excessive sun exposure. The mass media were the major source of information among the participants in our study. Data from Greek adult population regarding sun exposure behaviour and sun protection practices are limited. An improvement of sun-related knowledge and practices has been observed among Greek children and their mothers between 1993 and 2002. Until today, international experience on this issue has yielded conflicting results. However, most studies show that primary prevention campaigns based on sun education lead to an improvement of sun-related knowledge. This is more evident in high risk groups, as well as among skin cancer patients (secondary prevention). Nevertheless, this improved knowledge, most often did not result in safer sun-related behaviours. Conclusions Skin cancer incidence is on the rise. Therefore, prevention campaigns should be continued and enforced. New approaches should be tried, aiming to change sun- related believes, rather than just to improve knowledge. In these efforts, dermatologists should play the leading part.