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Print version ISSN 0365-0596
On-line version ISSN 1806-4841
An. Bras. Dermatol. vol.78 no.6 Rio de Janeiro Nov./Dec. 2003
CLINICAL, LABORATORY AND THERAPEUTIC INVESTIGATION
Evaluation about knowledge of skin cancer prevention and its relation with sun exposure among gym members in the city of Recife*
Clarissa da HoraI; Conceição Virgínia Costa BatistaII; Patricia de Barros GuimarãesII; Roberta SiqueiraIII; Sarita MartinsIV
IIM.D., Specialists in Dermatology
IVM.D., Specialist in Dermatology, masters degree in Dermatology
The prevalence of skin cancer is rising worldwide. It is important to know
the level of understanding of the population in the city of Recife.
OBJECTIVE: Faced with the lack of statistical data on the knowledge and prevention of negative effects of sun exposure and especially skin cancer, an epidemiological study was carried out on members attending the main gyms located in the city of Recife. The study aimed at assessing their knowledge about skin cancer and its prevention.
METHOD: Five hundred questionnaires comprising 22 items were applied to obtain data on each individual, notably age, sex, family income, educational level and behavior regarding sun exposure. Karl Pearson's chi-square test was applied for the statistical analysis. The frequency of similar replies was grouped in graphs and tables that allowed a discussion and comparison of the results with the literature.
RESULTS: Of the females in the sample, the majority were under 40 years of age. There were more whites than blacks and family income was over 10 times the Brazilian legal minimum wages.
CONCLUSION: The majority knew about the risks and damage associated with sun exposure as well as the means to protect the skin, nevertheless, those interviewed exposed themselves to these risks, but adopted various protective measures.
Key-words: skin aging; skin neoplasms.
The incidence of skin cancer has been increasing all over the world in the last three decades,1,3,4 and is the most common form of cancer. Many causes have been indicated: changes of life style with excessive sun exposure; the thinning of the ozone layer;3,10 an aging population;8 and earlier diagnosis of these cancers.8,10 Among the more outstanding phenotypic factors that increase susceptibility to cutaneous cancer are: skin type, color of the eyes and hair, presence of freckles and nevus, and a personal or family history of cutaneous cancer.5
Ultraviolet radiation (UVR) is a complete carcinogen. It begins the process of malignancy through mutations in the DNA and promotes the development of cancer by an inflammatory process inherent to cumulative exposure to UVR.2
UVR contributes to the development of both forms of skin cancer: melanoma and nonmelanoma. Nonmelanoma cancer is associated with cumulative solar action, and melanoma, to intense episodes of excessive sun exposure, resulting in sunburn.5 It may be observed that cutaneous manifestations present an evolutionary order of emergence: sunburn, a thickening of the skin, hyperchromic stains, fine wrinkles, deep wrinkles, actinic keratosis and finally skin cancer.2
MATERIAL AND METHOD
The study was accomplished in the Service of Dermatology of the Hospital das Clinicas, Federal University of Pernambuco (UFPE). A questionnaire was used comprising 22 items. Of the questions asked, l0 were multiple choice and three were open. Data was gathered about personal identification, phenotypic characteristics, socioeconomic condition, educational level, knowledge on the noxious effects of UVR, inadequate habits regarding sun exposure and preventive measures relevant to excessive sun exposure and skin cancer.
A total of 1,000 questionnaires were completed by frequenters of the major gyms in the city of Recife, of which 500 were analyzed, as this was considered to be a number of sufficient statistical value.
A descriptive analysis of the data was carried out with the purpose of evaluating the knowledge of preventive measures in relation to sun exposure. Pearson's Chi-square test was applied to detect associations between variables, such as age group, sex and level of education. All tests were applied with a 95% confidence level. The significance tests for the data were calculated using EPIINFO version 6.00 software.
It should be noted, however, that since the present work used a sample of those frequenting gyms, it dealt with individuals concerned with their health and that, in general, try to keep informed on health-related matters.
Of the 1,000 questionnaires, 500 were analyzed. Some interviewees failed to answer all of the items; consequently the percentages are presented on the basis of the number of individuals that answered each question.
The age distribution of the participants showed that 49.1% (n = 245) were between 20 and 40 years of age; 32.1% (n = 160) under 20 years old; 15.2% (n = 76) between 41 and 60 years of age, and 3.6% (n = 18) were > 60 years old. Thus, the population had a higher proportion of adolescents and young adults, with 62.8% (n = 314) women and 37.2% men (n = 186).
In terms of skin color, 66.8% (n = 334) of the interviewees were white, 31.0% (n = 155) mixed race, 1.2% (n = 6) black and 1.0% (n = 5) were yellow. In regard to the color of the eyes, 74.6% (n = 373) were brown; 12.4% (n = 62) black; 10.4% (n = 52) green and 2.2% (n = 11) blue. As for hair color, 65.4% (n = 327) of the interviewees had brown hair; 23.6% (n = 118) black; 10% (n = 50) blond and 0.6% (n = 3) were red-haired. It was thus observed the predominance of light skinned individuals with dark hair and eyes.
Regarding family income, 75.4% (n = 365) received over ten times the country's legal minimum salary; 15.3% (n = 74) between seven and ten; 6.6% (n = 32) between four and six salaries; and 2.7% (n = 13) between one and three.
As for the educational level, about 99.4% (n = 492) of the interviewees had attained a fairly high educational level either in grade school or in high school. The percentage of individuals without education was insignificant.
When these individuals were questioned about the injuries or consequences of sun exposure, 87.3% (n = 426) answered that they were aware of them. Of these, 65.8% (n = 280) were women and 32.2% (n = 146) were men.
An open question was asked regarding what the harmful effects of the sun are. Of the answers, 91.1% mentioned skin cancer, 19.9%, dark spots on the skin, and a smaller percentage, early aging and heatstroke (Graph 1).
As for the frequency of sun exposure, the result was as follows: 48.5% (n = 240) of the subjects would expose themselves to sun radiation occasionally; 36.1% (n = 179) only on weekends; and 15.5% (n = 77) daily.
A relationship was noted between age and the frequency of photoexposure. As the age increased, the percentage of individuals that exposed themselves daily to the sun decreased. A greater frequency of photoexposure was observed in individuals below 40 years of age. Those with the most frequent daily risk were under 20 years of age (50.6%).
It was observed that 72.2% of the interviewees exposed themselves to the sun in the critical time period from 9 a.m. to 3 p.m., 24% were exposed in the early morning, and 5.2% after 3 p.m.
Of these, 79% were exposed to the sun for leisure, and 10.2%, due to occupational reasons (Graph 2).
Of those affirming they protected themselves from the sun: 76% (n = 368), 43.8% protected both face and body, 33.4%, only the face, and 7.8%, only the body.
Table 1 shows that there is a relationship between age group and the use of sun protection. It was observed that, as the age increases, the percentage of individuals that protect themselves from the sun increases, and it was notable that 40.4% (n = 63) of the individuals below 20 years of age do not use any means of protection.
In relation to gender, there was also a significant statistical difference, indicating that of those that do not protect themselves from the sun, 69.8% (n = 179) were male and 73.4% (n = 270) were female. In this case, sun protection was defined as the use of sunscreens, clothes, hats or caps.
The individuals were questioned as to which measures they used to protect themselves against the sun. The most frequent measures of photoprotection were sunscreens (92%), dark glasses (63%) and hats (50.5%) (Graph 3).
Of the individuals that used sun protection, 52.6% were in the age group from 21 to 40 years, and 72.1% were female.
As for the frequency of the use of some form of sun protection, the majority, 56.8% (n = 281) used it during exposure to the sun, and only 29.9% (n = 148) on a daily basis, while 13.3% (n = 66) of the interviewees did not use it on any occasion.
Of the ones that used daily protection, 91.9% (n = 136) were women, and of the ones that did not use it on any occasion, 80.3% (n = 53) were men.
Regarding the source of information in the choice of a sun protection, it was observed that 44.3% followed the advice of a dermatologist, and that a similar percentage (41%) used a protection of their own choice (Graph 4).
The investigation into the use of sunscreen indicated that this is a practice that seems to be diminishing; since 88.6% (n = 437) of the respondents do not use sunscreen, against only 11.4% (n = 61) that do. Of the ones that use sunscreen, 83.6% (n = 51) were female, this being a statistically significant difference in comparison with the male sex (Graph 5). With regard to the age group, most (57.4%) were between 21 and 40 years of age (Graphs 5 and 6).
As for family history, 83.9% (n = 417) of the interviewees did not present antecedents of cutaneous cancer, but 16.1% (n = 80) reported cases of dermatologic neoplasias in the family.
In the present study there was a female predominance of 62.8%, in comparison with 31.2% of the male sex. The majority of the interviewees were of white skin color with dark eyes and hair (66.8%). The predominant age was under 40 years. Family income was above seven times the country's minimum salary in 90.7% of the cases.
As for the knowledge of the dangers related to sun exposure, it was observed that 87.3% of the interviewees said they were aware of the negative effects of exposure. These results were similar to those obtained by Martin in a work done in the south of Australia, according to which 91.5% of the individuals could name some injury caused by the sun: skin cancer and among its variations, melanoma.1
Gebert,7 in a study accomplished at the National Institute of Cancer in the United States, found that 77% of the participants were aware that sun radiation increases the risk of cutaneous cancer. However, in that same study, only 10% of the respondents actively reduced or avoided sun exposure.7
The higher the educational degree achieved by individuals at school or university level, the greater the percentage of those knowledgeable of the damage or consequences of photoexposure.
Of the individuals with knowledge about photodamage, 65.8% were women. Of the ones that did not know, 58.1% were men. Perhaps this fact is probably due to the greater concern of women with esthetics and skin care.
In the sample analyzed, only 14% of the interviewees mentioned early cutaneous aging as a consequence of sun exposure. Porto and Tarlé, cited by Garrido et al., advise that injudicious exposure to the sun should be associated with extrinsic cutaneous manifestations of aging, besides the social importance attributed to these manifestations and by means of its prevention, reduce the risks of cutaneous cancer.8
The reasons for sun exposure were also analyzed, whether during leisure time or in the work place. It was found that 79% of the participants exposed themselves to the sun in moments of leisure, and 10.2% due to need of work. Correlating these results with the variable of gender, it was clear that most of those that were exposed in leisure were female (65.9%) and that, of the ones that are exposed at work, the majority were male, although this last result did not present a statistically significant difference (p <0.05). It is logical though, in spite of this small difference in the percentage, that there really exists a tendency for occupational exposure to be more frequent in male workers.
In the present work, 76% of the individuals in some way protect themselves from the sun, while 24% do not use any form of sun protection. A study carried out on swimming clubs in the USA showed that 91% of the clubs offered one or more protection items close to the swimming pool (sunscreen, beach umbrella, cover providing shade...).3
It was observed that in general adolescents and young adults do not protect themselves or do so in an inadequate manner, because in the results presented, 40.4% of the individuals under 20 years of age did not use any measure of protection. Regarding those that specifically did not use sun protection, 65,2% were less than 20 years old.
Rosemberg et al.3 demonstrated that children are not adequately protected against the sun. These authors point out the need for appropriate sun protection in childhood and adolescence. Due to the long latency phase of carcinogenesis and early aging related to exposure to UVR, such intervention appears to be more effective if initiated in infancy.3,10
The frequency of sun exposure was correlated with the variables of age and sex. Regarding age group, it was observed that as age increases, the percentage of individuals susceptible to daily solar radiation decreases. It was found that 83% of those that subjected themselves to daily solar radiation and 76% of those that were exposed on weekends, were less than 40 years old. These results are a matter of some concern because it is known that, although the clinical onset of skin tumors occurs predominantly in advanced ages, sun exposure is the major factor of environmental risk in the development of cutaneous neoplasias.11,12
Considering variable of sex, it was demonstrated that 59.7% of those that were exposed to UVR on a daily basis were men, this result being related to occupational exposure, which is usually greater among males.
Interviews carried out in Marseilles, regarding the habits of children and adolescents showed that 35% of the three-year-olds and 45% of the adolescents spent more than 15 hours a week exposed to the sun in the critical period between 11 a.m. and 4 p.m. That work showed that 78% of the mothers of small children and 61% of the adolescents were aware that sun exposure causes photoaging and cancer of the skin.13 These data demonstrate that knowledge alone does not necessarily lead to taking personal care with regard to sun exposure.
In the present study, the principal measure of protection used was a sunscreen (92.7%), followed by dark glasses (63%) and keeping under shade (50.5%). A similar work accomplished in Australia concluded also that the main measure of protection used was a sunscreen (73.7%), followed by appropriate clothing (53.9%) and shade (15.5%). In that work the greater use of sunscreen protection as a prevention measure was attributed to its lower cost, to the fact of it being a simple method, easy to use and effective.1
In the work presented here the same correlation can also be made, since sunscreen was the measure most used, and 70.4% of the interviewees answered that the price did not hinder its purchase.
The frequency of the use of a sun protection was also analyzed, and it was observed that, in spite of a high percentage (92.7%) utilizing some form of sun protection, the greater frequency of use is only during intentional exposure (56.8%). This is unfortunate because in areas such as the Northeast of Brazil the sun is prevalent all year around, and even on cloudy days the clouds allow the passage of 80% of the solar radiation. It is therefore prudent to use protection on a daily basis, a precaution taken by only 29.9% of the individuals interviewed.
A tendency to recognize the importance of dermatological recommendations when choosing a sun protection was verified, since 44% of the respondents followed the advices of their dermatologists. However, many individuals still make their own choice as to the protection they use.
Apparently at the present time the use of sunscreen products is being gradually abandoned. It was observed that only 11.4% of the sample actually used them, and, of those, 83.6% were women. These people are probably still caught up in the traditional concept of tanned skin being considered beautiful and "healthy".6
From a broad perspective, people have a notion of the malevolent effects caused by excessive exposure to the sun, but nevertheless are exposing themselves in varying frequencies and in the critical hours, the greatest exposure being among the younger generation and especially males.
Although protection measures were being used by most of the sample, these were applied in an inconsistent manner and then only when exposure to the sun was intentional. It is notable, however, that there have been results from the efforts of dermatologists, whether it be by individual contact in the clinics or through educational campaigns. It is essential to amplify the concepts and the knowledge of prevention in order to reduce the incidence and mortality of skin cancer in the population.
This work presents data regarding a situation little known in Brazil, in spite of the fact of having been widely studied in other countries.
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Patricia de Barros Guimarães
Rua da Harmonia 430 / 804
Casa Amarela Recife 52051-390
Tel/Fax: (81) 3441-5792
Received in June,
28th of 2002
Approved by the Consultive Council and accepted for publication in July, 08th of 2003
* Work done at "Hospital das Clínicas, Universidade Federal de Pernambuco".