Australas J. Dermatol 1991; 32: 21-25
SUNSCREEN USE ON QUEENSLAND BEACHES MATTHEW W. PINCUS, P. KARL ROLLINGS, ALLAN B. CRAFT AND ADELE GREEN
Brisbane SUMMARY
''"'
The prevalence of use of sunscreens was assessed in an environment of high ultraviolet (UV) exposure by surveying U7 males and 126females on two Queensland beaches. Using a questionnaire, information was obtained about their application of sunscreen on the day of participation in the study, thus eliminating recall error. It was found that 71% of the female and 68% of the male beach-goers sampled had applied sunscreen, 47% of which had the maximum Sun Protection Factor (15 +) rating. There was no significant association found between usage and either skin colour or socio-economic status. Although 88% used a waterproofformulation, only 61% reapplied the sunscreen directly after swimming. Sunscreen was not applied to all exposed body parts, with over half of the subjects neglecting ears and lower limbs. Reported major reasons for use were to avoid skin cancer (44%), and to avoid sunburn (43%). The results of this study can assist in evaluating the effectiveness ofpresent sun-protection campaigns in the short term. Key words: sunscreens, ultraviolet radiation, beach survey, skin cancer. sun, such as the national "Slip! Slop! Slap!" campaign. Current evaluation of such programmes is only possible by assessing behavioural end-points, given the absence of routine monitoring of non-melanocytic skin cancer in the community'. However few research data are available. In late 1986 and early 1987 Cockburn el al'' examined use of sun-protection measures in 2029 adolescents in New South Wales high schools. Sunscreens were rated as method of first choice by 44% of students, followed by wearing a shirt (35% of students). Borland et aP recently surveyed community awareness of the need for precautions against overexposure to the sun before and after a large public education campaign. They found high awareness matched by knowledge of appropriate behaviour and increased reporting of taking precautions.
INTRODUCTION
The consequences of excessive sun exposure represent a major public health problem in Australia. Latest national figures suggest that 140,000 Australians have non-melanocytic skin cancers treated each year, and over 200 cases prove fatal; total minimum costs to the community are estimated at $A50,000,000 per annum'. It would therefore seem desirable that persons susceptible to the long-term effects of sun exposure be aware of appropriate preventive action. When direct sun exposure cannot be avoided, the use of topical chemical sunscreens which filter solar ultraviolet (UV) radiation is an increasingly popular alternative. The effectiveness of sunscreens in reducing sunburn in humans is well-established-, and animal studies demonstrate that these agents reduce the risk of both UVinduced premature ageing' and UV-induced skin tumours^ Many public education campaigns in Australia aim to raise awareness of the need to use sunscreens and take other precautions against the
Few other relevant studies have been published. In particular, behaviour with regard to sunprotection while subjects are actually in the sun has never been systematically assessed. Consequently, trends in Australians' use of sunprotection and therefore the effect of domestic education campaigns in improving such behaviour are not accurately known. The purpose of this study was to provide some baseline data about people's use of chemical sunscreens in summer while sitting on the beach, where UV intensity is high, and sun-protection from shelter
Matthew W. Pincus, P. Karl Rollings and Allan B. Craft. Medical Students, Social and Preventive Medicine Department, University of Queensland Medical School. Adele Green, MBBS, MSc, PhD. Senior Research Fellow, Queensland Institute of Medical Research. Address for correspondence: Dr Adele Green, Queensland Institute of Medical Research, Bramston Terrace, Herston, Brisbane 4006, Queensland. (Fax 07-252-5499)
21
M.W. PiNCUS, P.K. ROLLINGS, or clothing is often minimal. In addition to ascertaining prevalence of use, we also wished to describe the general types of sunscreens used, the parts of the body to which sunscreen was being applied and to clarify reasons for use. SUBJECTS AND METHODS
Study Population People who were at one of two beach locations in south-east Queensland, Sunshine Beach or Surfers' Paradise-Main Beach, between the hours of 12.00 noon and 2.30 p.m. on random days in March, 1989 were eligible for study. These are popular patrolled beaches 120 kms north and 60 kms south of Brisbane respectively. Sampling Method On such patrolled beaches two lifesavers' flags indicate the safest swimming area and consequently define the area of beach with the greatest density of people. One flag was designated the starting point for ascertainment and the person nearest the flag was approached, followed by the person nearest this first person and so on, always working in the direction of the second flag. Once the second flag was reached, samphng was continued in the same direction outside the flagged area of the beach. No age limits or other restrictions were applied and there was a 100% response rate. Accompanying adults provided information for children under 10 years. Data Collected
Information obtained from the standard selfadministered questionnaire included age, sex, place of residence (including which Brisbane suburb if applicable) and skin colour on areas (the few) rarely exposed to the sun. Details of sunscreens included whether or not a sunscreen had been applied on the day of participation in the survey; the sun protection factor (SPF) rating of the sunscreen used; whether it was a waterproof formulation; whether or not sunscreen was normally applied directly after swimming; and exposed areas of the body to which sunscreen had not been applied. Users were also asked "What is the main reason you are wearing sunscreen?" and given five options: to avoid sunburn, to promote tanning, to avoid skin cancer, to prevent premature ageing or another reason. No information was gathered about other possible precautions taken such as hat wearing or sitting under beach umbrellas.
A . B . CRAFT AND
A.
GREEN
Analysis The significance of associations between use of sunscreen and factors from the questionnaire was assessed with the use of the chi-squared test for nominal variables, and for ordered or semiquantitative variables Kendall's rank correlation statistic* was used. Socio-economic status scores based on 1981 census information regarding Brisbane suburbs were allotted to Brisbane residents in the study'. RESULTS
A total of 243 questionnaires were distributed to people on the beach on six random days, four of which were sunny and two of which were lightly to moderately overcast. The mean maximum temperature in the Brisbane coastal region during the study month was 27.0''C. The age and sex distribution of respondents (Table 1) reflects that of a typical beach population in Queensland; the median age was 27 years (range 2 to 78 years). The majority (94%) were Australian residents, half of whom lived in Brisbane. Asked about natural skin colour, 44% of respondents rated theirs as medium, 37% as fair, and 19% said they had an olive or dark skin. On the day of their participation in the study, 70% of beach-goers were using a suncreen. Use varied sigificantly with age (p -^ 0.05) with maximum use in the 20-29 year age group (Table 1). Age patterns were similar in both sexes, apart from a lower prevalence of use (39%) among men than among women (85%) aged 40 years or more (Table 1). There were no significant differences in use according to skin colour although a trend was observed: 76% people with fair, 68% with medium, and 63% with olive or dark complexion types had applied sunscreens while on the beach. TABLE 1 Prevalence of sunscreen use among 243 beach-goers by sex and age Sex No. (Years) -* 10 10-19 20-29 30-39 tf 40 Total
22
Total % of Users
No.
Male % of Users
No.
Female % of Users
8
50
3
67
5
40
35
57
54
22
59
124 26
79 62
13 63
84
61
74
50
64
15 23
60 39
II 27
64 85
243
70
117
68
126
71
SUNSCREEN USE ON QUEENSLAND BEACHES
Socio-economic scores of users tended to be higher (non-significantly) than non-users. Slightly less than half (47%) of both male and female users had a sunscreen with SPF 15-I-. Sunscreen SPF level was not significantly associated with sex or age, though an increase in the prevalence of use of sunscreen of SPF 15-1- was observed from the 10-19 age group to the 20-29 age group. When SPF level was analysed in relation to complexion of users, patterns were similar for people with olive/dark skin and those with fair skin, with more than 50% of people using SPF 15-f in each of these categories. In comparison, those who described their complexion as medium tended to use the lower SPF formulations more often, with only 39% using
SPF 15-I-. Among users, 88% had a waterproof formulation; 61% of all users applied sunscreen directly after swimming. Over half of all users neglected to apply sunscreen to the ears or to the lower limbs (Table 2) while the face and shoulders were the most common sites of application. Almost half of the females reported prevention of cancer as their reason for sunscreen use, whereas over half of the males reported avoidance of sunburn as their reason for use (Table 3). Among females avoidance of cancer was given increasingly as the reason for sunscreen use with increasing age, and sunburn prevention as the reason for use decreased with age. No such trends were demonstrable for males (Table 3). There was no association between reason for use and socioeconomic status. : ,
TABLE 2 Percentages of sunscreen users who neglected exposed body areas during application
- / DISCUSSION - '':,-- . The principal aim of this survey was to obtain for the first time accurate data about prevalence of sunscreen use among people sitting on Queensland beaches. We found that 7 out of 10 people on the beaches surveyed had applied sunscreen formulations on the day they were questioned, with little difference in overall prevalence of use between the sexes. However, considering specific age-groups, women over 40 years were most likely to be users while men over 40 years were least likely to be users of sunscreens. Socio-economic status of users tended to be higher than non-users. No other studies are
Neglect of application n % of users
Body Area Nose Cheeks Ears Neck Shoulders Back Chest/abdomen Arms Front of legs Back of legs
15 22 93 46 27 42 42 48 87 99
8.8 13 55 27 16 25 25 28 51 58
TABLE 3 Main reasons for sunscreen use by sex and age Sex Male Age (years) 20-29 30-39 40 +
Reason Avoid sunburn n Avoid cancer n Promote tanning n Prevent ageing n Total t
, ,
Tolal
• 20
Female Age (years) 20-29 30-39 40 +
Total
6 (67)
27 (51)
6 (75)
5 (56)
44 (56)
10 (67)
13 (30)
2 (29)
4 (17)
29 (33)
3 (33)
23 (43)
2 (25)
3 (33)
31 (39)
4 (27)
19 (44)
4 (57)
16 (70)
43 (49)
0
3 (6)
0
4 (5)
1 (7)
6 (14)
0
(11)
2 (9)
9 (10)
0
0
0
0
0
0
9
53
8
9
79
15
5 (12) 43
1 (14) 7
1 (4) 23
7 (8) 88
fOne male and two females with missing information
.23
M.W. PiNcus, P.K. ROLLINGS, A.B. CRAFT AND A. GREEN available with findings which can be directly compared with ours, and we regard these as valuable baseline data about sun-protection use among Australian beach-goers. There are some considerations that may limit generalisation of these results, given that the method of sampling, while systematic, was not random. Possible selection bias may have occurred because it is common for people to sit in social groups on beaches, or because sampling may have been Influenced to some degree by the physical appearance of potential participants. Surfboard riders and others who spend much of their time in the water were probably underrepresented. Furthermore people who were on the beach during the study times of peak UV intenity could be different from those who sought shade at these times, perhaps in resonse to education campaigns. However, the internal validity of the data is not threatened. By questioning people only about sunscreen use at the time they were seen, information should be highly accurate since recall bias was obviated: people referred to the product they were carrying, and no opinions or judgements were sought which could vary. With regard to sun protection factor ratings of the sunscreen formulations, we found that overall 47% of users applied SPF 15-1- formulations (it is recommended that SPF 15+ formulations be used by all people whatever their skin types), with no statistically significant difference between the sexes with regard to SPF rating of the sunscreen used. Whether the tendency for people with medium complexions to use lower SPF sunscreens is indeed due to chance (p • 0.05), or if it is due to their desire to develop a darker skin colour whilst still getting some protection, or some other reason, is unknown. A waterproof formulation was used by 88% of sunscreen users, though fewer (61%) reapplied any screen directly after swimming. Thus it may be that although people are conscientious in their selection of waterproof sunscreens, they may not be aware of the need to reapply sunscreen (once they are dry) after a period in the water, since the effectiveness of "waterproof" formulations is decreased by swimming. When spending time on the beach, it is important that people should apply sunscreen to all exposed body parts if skin damage is to be avoided. We found that many people apply sunscreen to their nose, cheeks and shoulders, but neglect other areas, particularly the ears and
lower limbs (back and front) which more than half of the participants left unprotected. It may be that the sites ignored are those less often acutely sunburnt and hence perceived as being less vulnerable to chronic sun-induced skin damage than other skin areas. Finally it is useful to know the reasons for use of sunscreens. Our results indicate that the vast majority of people using sunscreen did so in order to prevent skin cancer (44%) or sunburn (43%). This is generally consistent with findings in Victoria'". On the basis that sound health education should be based on behaviourial theory. Hill et al'" examined psychological factors related to use of sun-protective measures in 150 volunteer adults. They found that the beliefs determining use of sunscreen were that it prevents skin cancer; it prevents general skin damage (especially women); and it assists getting a suntan (men only). Similarly, in California, Keesling and Friedman" studying psychological factors underlying sunbathing and sunscreens found that sunscreen use was determined by sex, knowledge of skin cancer and/or knowledge of other persons affected, and having a high level of anxiety. Although they surveyed beach-goers, their principal concern was to examine the psychology of sunbathing and they therefore selected participants in their study on the basis of their suntans. Among females in our survey, prevention of skin cancer assumed greater importance as a reason for use as they became older, suggesting that future skin cancers seem a remote hazard to young women. It may be that for teenagers and young adults, education campaigns can be made more effective by concentrating less on skin cancer, and more on other consequences of sun exposure such as premature ageing. The finding that socio-economic status and reasons for use were not associated suggests that current education campaigns reach social groups in the community equally. The results of this cross-sectional study form a useful baseline for evaluation of sun-protection campaigns, though information on long term use of sunscreens is needed. How sunscreens complement other protection measures is also of interest, given that even SPF 15+ formulations do not screen 100% of potentially harmful UV radiation. We have demonstrated that most beach-goers are using sunscreens. However, there are specific inadequacies including use of low SPF-rated sunscreens by susceptible persons, low 24
SUNSCREEN USE ON QUEENSLAND BEACHES Pathak MA. Sunscreens and their use in the preventive treatment of sunlight-induced skin damage. J Dermatol Surg Oncoi 1987; 13: 739-750. Green A, MacLennan R. Monitoring and surveillance of skin cancer. Trans Menzies Found 1989; 15: 193-199. Cockburn J, Hennrikus D, Scott R, Sanson-Fisher R. Adolescent use of sun-protection measures. Med J Ausi 1989; 151: 136-140. Borland R, Hill D, Noy S. Being Sun Smart: Changes in community awareness and reported behaviour following a primary prevention program for skin cancer control. Behav Change (in press). Kendall MG. Rank correlation methods: London: Chas Griffin, 1962. Siskind V, Najman JM, Copeman R. Infant mortality in socio-economically advantaged and disadvantaged areas of Brisbane. Comm Health Studies 1987; 1: 24-30. Hill D, Rassaby J, Gardner G. Determinants of intentions to take precautions against skin cancer. Comm Health Studies 1984; 8: 33-44. Keesling B, Friedman HS: Psychosocial factors in sunbathing and sunscreen use. Health Psychol 1987; 6: 477-493.
rates of reapplication following swimming and neglect of vulnerable sun-exposed areas of skin. It is perhaps time to focus on more subtle aspects of efficacious sunscreen use in education campaigns as well as continuing to emphasise the carcinogenic effect of sunlight. ACKNOWLEDGEMENTS
We are grateful to Dr Robin Marks for his helpful comments on the paper.
REFERENCES Giles GG, Marks R, Foley P. Incidence of non-melanocytic skin cancer treated in Australia. BrMedJ 1988; 296: 13-16. Cripps DJ, Hegedus S. Protection factor of sunscreens to monochrotnatic radiation. Arch Dermalol 1982; 7: 285-312. Kligman RH: Photoaging - manifestations, prevention, and treatment. Derm Clinics 1986; 4: 517-528.
BOOK REVIEW Clinical Dermatology JAA Hunter, JA Savin and MV Dahl. Blackwell Scientific Publications, England, 1989. 272 pages. RRP $56. General practitioners and medical students frequently ask dermatologists to recommend a dermatology book to which they can relate. Many such books are produced but few stand the test of time. "Clinical Dermatology" by Hunter Savin & Dahl is an attempt to reach this market on both sides of the Atlantic. It is jointly written by well-known dermatologists from the University of Edinburgh and the University of Minnesota and in large measures it achieves its aim. The book is well printed with excellent colour photographs. It opens with two introductory
chapters on structure function and immunology of the skin, and finishes with a section on treatment aimed at readers from both the United Kingdon and USA. In the rest of the 272 pages of the book there is a standard treatment of dermatology topics which is up to the minute and which contains useful tables and diagrams and helpful learning points. More emphasis on problem solving would have been of benefit and there is a tendency to include many rare conditions which may add to completeness but in a book of this type creates problems of emphasis. It is likely that this well produced book will have a significant appeal to its target audience. J.A.B. 25
SUNSCREEN USE ON QUEENSLAND BEACHES MATTHEW W. PINCUS, P. KARL ROLLINGS, ALLAN B. CRAFT AND ADELE GREEN
Brisbane SUMMARY
''"'
The prevalence of use of sunscreens was assessed in an environment of high ultraviolet (UV) exposure by surveying U7 males and 126females on two Queensland beaches. Using a questionnaire, information was obtained about their application of sunscreen on the day of participation in the study, thus eliminating recall error. It was found that 71% of the female and 68% of the male beach-goers sampled had applied sunscreen, 47% of which had the maximum Sun Protection Factor (15 +) rating. There was no significant association found between usage and either skin colour or socio-economic status. Although 88% used a waterproofformulation, only 61% reapplied the sunscreen directly after swimming. Sunscreen was not applied to all exposed body parts, with over half of the subjects neglecting ears and lower limbs. Reported major reasons for use were to avoid skin cancer (44%), and to avoid sunburn (43%). The results of this study can assist in evaluating the effectiveness ofpresent sun-protection campaigns in the short term. Key words: sunscreens, ultraviolet radiation, beach survey, skin cancer. sun, such as the national "Slip! Slop! Slap!" campaign. Current evaluation of such programmes is only possible by assessing behavioural end-points, given the absence of routine monitoring of non-melanocytic skin cancer in the community'. However few research data are available. In late 1986 and early 1987 Cockburn el al'' examined use of sun-protection measures in 2029 adolescents in New South Wales high schools. Sunscreens were rated as method of first choice by 44% of students, followed by wearing a shirt (35% of students). Borland et aP recently surveyed community awareness of the need for precautions against overexposure to the sun before and after a large public education campaign. They found high awareness matched by knowledge of appropriate behaviour and increased reporting of taking precautions.
INTRODUCTION
The consequences of excessive sun exposure represent a major public health problem in Australia. Latest national figures suggest that 140,000 Australians have non-melanocytic skin cancers treated each year, and over 200 cases prove fatal; total minimum costs to the community are estimated at $A50,000,000 per annum'. It would therefore seem desirable that persons susceptible to the long-term effects of sun exposure be aware of appropriate preventive action. When direct sun exposure cannot be avoided, the use of topical chemical sunscreens which filter solar ultraviolet (UV) radiation is an increasingly popular alternative. The effectiveness of sunscreens in reducing sunburn in humans is well-established-, and animal studies demonstrate that these agents reduce the risk of both UVinduced premature ageing' and UV-induced skin tumours^ Many public education campaigns in Australia aim to raise awareness of the need to use sunscreens and take other precautions against the
Few other relevant studies have been published. In particular, behaviour with regard to sunprotection while subjects are actually in the sun has never been systematically assessed. Consequently, trends in Australians' use of sunprotection and therefore the effect of domestic education campaigns in improving such behaviour are not accurately known. The purpose of this study was to provide some baseline data about people's use of chemical sunscreens in summer while sitting on the beach, where UV intensity is high, and sun-protection from shelter
Matthew W. Pincus, P. Karl Rollings and Allan B. Craft. Medical Students, Social and Preventive Medicine Department, University of Queensland Medical School. Adele Green, MBBS, MSc, PhD. Senior Research Fellow, Queensland Institute of Medical Research. Address for correspondence: Dr Adele Green, Queensland Institute of Medical Research, Bramston Terrace, Herston, Brisbane 4006, Queensland. (Fax 07-252-5499)
21
M.W. PiNCUS, P.K. ROLLINGS, or clothing is often minimal. In addition to ascertaining prevalence of use, we also wished to describe the general types of sunscreens used, the parts of the body to which sunscreen was being applied and to clarify reasons for use. SUBJECTS AND METHODS
Study Population People who were at one of two beach locations in south-east Queensland, Sunshine Beach or Surfers' Paradise-Main Beach, between the hours of 12.00 noon and 2.30 p.m. on random days in March, 1989 were eligible for study. These are popular patrolled beaches 120 kms north and 60 kms south of Brisbane respectively. Sampling Method On such patrolled beaches two lifesavers' flags indicate the safest swimming area and consequently define the area of beach with the greatest density of people. One flag was designated the starting point for ascertainment and the person nearest the flag was approached, followed by the person nearest this first person and so on, always working in the direction of the second flag. Once the second flag was reached, samphng was continued in the same direction outside the flagged area of the beach. No age limits or other restrictions were applied and there was a 100% response rate. Accompanying adults provided information for children under 10 years. Data Collected
Information obtained from the standard selfadministered questionnaire included age, sex, place of residence (including which Brisbane suburb if applicable) and skin colour on areas (the few) rarely exposed to the sun. Details of sunscreens included whether or not a sunscreen had been applied on the day of participation in the survey; the sun protection factor (SPF) rating of the sunscreen used; whether it was a waterproof formulation; whether or not sunscreen was normally applied directly after swimming; and exposed areas of the body to which sunscreen had not been applied. Users were also asked "What is the main reason you are wearing sunscreen?" and given five options: to avoid sunburn, to promote tanning, to avoid skin cancer, to prevent premature ageing or another reason. No information was gathered about other possible precautions taken such as hat wearing or sitting under beach umbrellas.
A . B . CRAFT AND
A.
GREEN
Analysis The significance of associations between use of sunscreen and factors from the questionnaire was assessed with the use of the chi-squared test for nominal variables, and for ordered or semiquantitative variables Kendall's rank correlation statistic* was used. Socio-economic status scores based on 1981 census information regarding Brisbane suburbs were allotted to Brisbane residents in the study'. RESULTS
A total of 243 questionnaires were distributed to people on the beach on six random days, four of which were sunny and two of which were lightly to moderately overcast. The mean maximum temperature in the Brisbane coastal region during the study month was 27.0''C. The age and sex distribution of respondents (Table 1) reflects that of a typical beach population in Queensland; the median age was 27 years (range 2 to 78 years). The majority (94%) were Australian residents, half of whom lived in Brisbane. Asked about natural skin colour, 44% of respondents rated theirs as medium, 37% as fair, and 19% said they had an olive or dark skin. On the day of their participation in the study, 70% of beach-goers were using a suncreen. Use varied sigificantly with age (p -^ 0.05) with maximum use in the 20-29 year age group (Table 1). Age patterns were similar in both sexes, apart from a lower prevalence of use (39%) among men than among women (85%) aged 40 years or more (Table 1). There were no significant differences in use according to skin colour although a trend was observed: 76% people with fair, 68% with medium, and 63% with olive or dark complexion types had applied sunscreens while on the beach. TABLE 1 Prevalence of sunscreen use among 243 beach-goers by sex and age Sex No. (Years) -* 10 10-19 20-29 30-39 tf 40 Total
22
Total % of Users
No.
Male % of Users
No.
Female % of Users
8
50
3
67
5
40
35
57
54
22
59
124 26
79 62
13 63
84
61
74
50
64
15 23
60 39
II 27
64 85
243
70
117
68
126
71
SUNSCREEN USE ON QUEENSLAND BEACHES
Socio-economic scores of users tended to be higher (non-significantly) than non-users. Slightly less than half (47%) of both male and female users had a sunscreen with SPF 15-I-. Sunscreen SPF level was not significantly associated with sex or age, though an increase in the prevalence of use of sunscreen of SPF 15-1- was observed from the 10-19 age group to the 20-29 age group. When SPF level was analysed in relation to complexion of users, patterns were similar for people with olive/dark skin and those with fair skin, with more than 50% of people using SPF 15-f in each of these categories. In comparison, those who described their complexion as medium tended to use the lower SPF formulations more often, with only 39% using
SPF 15-I-. Among users, 88% had a waterproof formulation; 61% of all users applied sunscreen directly after swimming. Over half of all users neglected to apply sunscreen to the ears or to the lower limbs (Table 2) while the face and shoulders were the most common sites of application. Almost half of the females reported prevention of cancer as their reason for sunscreen use, whereas over half of the males reported avoidance of sunburn as their reason for use (Table 3). Among females avoidance of cancer was given increasingly as the reason for sunscreen use with increasing age, and sunburn prevention as the reason for use decreased with age. No such trends were demonstrable for males (Table 3). There was no association between reason for use and socioeconomic status. : ,
TABLE 2 Percentages of sunscreen users who neglected exposed body areas during application
- / DISCUSSION - '':,-- . The principal aim of this survey was to obtain for the first time accurate data about prevalence of sunscreen use among people sitting on Queensland beaches. We found that 7 out of 10 people on the beaches surveyed had applied sunscreen formulations on the day they were questioned, with little difference in overall prevalence of use between the sexes. However, considering specific age-groups, women over 40 years were most likely to be users while men over 40 years were least likely to be users of sunscreens. Socio-economic status of users tended to be higher than non-users. No other studies are
Neglect of application n % of users
Body Area Nose Cheeks Ears Neck Shoulders Back Chest/abdomen Arms Front of legs Back of legs
15 22 93 46 27 42 42 48 87 99
8.8 13 55 27 16 25 25 28 51 58
TABLE 3 Main reasons for sunscreen use by sex and age Sex Male Age (years) 20-29 30-39 40 +
Reason Avoid sunburn n Avoid cancer n Promote tanning n Prevent ageing n Total t
, ,
Tolal
• 20
Female Age (years) 20-29 30-39 40 +
Total
6 (67)
27 (51)
6 (75)
5 (56)
44 (56)
10 (67)
13 (30)
2 (29)
4 (17)
29 (33)
3 (33)
23 (43)
2 (25)
3 (33)
31 (39)
4 (27)
19 (44)
4 (57)
16 (70)
43 (49)
0
3 (6)
0
4 (5)
1 (7)
6 (14)
0
(11)
2 (9)
9 (10)
0
0
0
0
0
0
9
53
8
9
79
15
5 (12) 43
1 (14) 7
1 (4) 23
7 (8) 88
fOne male and two females with missing information
.23
M.W. PiNcus, P.K. ROLLINGS, A.B. CRAFT AND A. GREEN available with findings which can be directly compared with ours, and we regard these as valuable baseline data about sun-protection use among Australian beach-goers. There are some considerations that may limit generalisation of these results, given that the method of sampling, while systematic, was not random. Possible selection bias may have occurred because it is common for people to sit in social groups on beaches, or because sampling may have been Influenced to some degree by the physical appearance of potential participants. Surfboard riders and others who spend much of their time in the water were probably underrepresented. Furthermore people who were on the beach during the study times of peak UV intenity could be different from those who sought shade at these times, perhaps in resonse to education campaigns. However, the internal validity of the data is not threatened. By questioning people only about sunscreen use at the time they were seen, information should be highly accurate since recall bias was obviated: people referred to the product they were carrying, and no opinions or judgements were sought which could vary. With regard to sun protection factor ratings of the sunscreen formulations, we found that overall 47% of users applied SPF 15-1- formulations (it is recommended that SPF 15+ formulations be used by all people whatever their skin types), with no statistically significant difference between the sexes with regard to SPF rating of the sunscreen used. Whether the tendency for people with medium complexions to use lower SPF sunscreens is indeed due to chance (p • 0.05), or if it is due to their desire to develop a darker skin colour whilst still getting some protection, or some other reason, is unknown. A waterproof formulation was used by 88% of sunscreen users, though fewer (61%) reapplied any screen directly after swimming. Thus it may be that although people are conscientious in their selection of waterproof sunscreens, they may not be aware of the need to reapply sunscreen (once they are dry) after a period in the water, since the effectiveness of "waterproof" formulations is decreased by swimming. When spending time on the beach, it is important that people should apply sunscreen to all exposed body parts if skin damage is to be avoided. We found that many people apply sunscreen to their nose, cheeks and shoulders, but neglect other areas, particularly the ears and
lower limbs (back and front) which more than half of the participants left unprotected. It may be that the sites ignored are those less often acutely sunburnt and hence perceived as being less vulnerable to chronic sun-induced skin damage than other skin areas. Finally it is useful to know the reasons for use of sunscreens. Our results indicate that the vast majority of people using sunscreen did so in order to prevent skin cancer (44%) or sunburn (43%). This is generally consistent with findings in Victoria'". On the basis that sound health education should be based on behaviourial theory. Hill et al'" examined psychological factors related to use of sun-protective measures in 150 volunteer adults. They found that the beliefs determining use of sunscreen were that it prevents skin cancer; it prevents general skin damage (especially women); and it assists getting a suntan (men only). Similarly, in California, Keesling and Friedman" studying psychological factors underlying sunbathing and sunscreens found that sunscreen use was determined by sex, knowledge of skin cancer and/or knowledge of other persons affected, and having a high level of anxiety. Although they surveyed beach-goers, their principal concern was to examine the psychology of sunbathing and they therefore selected participants in their study on the basis of their suntans. Among females in our survey, prevention of skin cancer assumed greater importance as a reason for use as they became older, suggesting that future skin cancers seem a remote hazard to young women. It may be that for teenagers and young adults, education campaigns can be made more effective by concentrating less on skin cancer, and more on other consequences of sun exposure such as premature ageing. The finding that socio-economic status and reasons for use were not associated suggests that current education campaigns reach social groups in the community equally. The results of this cross-sectional study form a useful baseline for evaluation of sun-protection campaigns, though information on long term use of sunscreens is needed. How sunscreens complement other protection measures is also of interest, given that even SPF 15+ formulations do not screen 100% of potentially harmful UV radiation. We have demonstrated that most beach-goers are using sunscreens. However, there are specific inadequacies including use of low SPF-rated sunscreens by susceptible persons, low 24
SUNSCREEN USE ON QUEENSLAND BEACHES Pathak MA. Sunscreens and their use in the preventive treatment of sunlight-induced skin damage. J Dermatol Surg Oncoi 1987; 13: 739-750. Green A, MacLennan R. Monitoring and surveillance of skin cancer. Trans Menzies Found 1989; 15: 193-199. Cockburn J, Hennrikus D, Scott R, Sanson-Fisher R. Adolescent use of sun-protection measures. Med J Ausi 1989; 151: 136-140. Borland R, Hill D, Noy S. Being Sun Smart: Changes in community awareness and reported behaviour following a primary prevention program for skin cancer control. Behav Change (in press). Kendall MG. Rank correlation methods: London: Chas Griffin, 1962. Siskind V, Najman JM, Copeman R. Infant mortality in socio-economically advantaged and disadvantaged areas of Brisbane. Comm Health Studies 1987; 1: 24-30. Hill D, Rassaby J, Gardner G. Determinants of intentions to take precautions against skin cancer. Comm Health Studies 1984; 8: 33-44. Keesling B, Friedman HS: Psychosocial factors in sunbathing and sunscreen use. Health Psychol 1987; 6: 477-493.
rates of reapplication following swimming and neglect of vulnerable sun-exposed areas of skin. It is perhaps time to focus on more subtle aspects of efficacious sunscreen use in education campaigns as well as continuing to emphasise the carcinogenic effect of sunlight. ACKNOWLEDGEMENTS
We are grateful to Dr Robin Marks for his helpful comments on the paper.
REFERENCES Giles GG, Marks R, Foley P. Incidence of non-melanocytic skin cancer treated in Australia. BrMedJ 1988; 296: 13-16. Cripps DJ, Hegedus S. Protection factor of sunscreens to monochrotnatic radiation. Arch Dermalol 1982; 7: 285-312. Kligman RH: Photoaging - manifestations, prevention, and treatment. Derm Clinics 1986; 4: 517-528.
BOOK REVIEW Clinical Dermatology JAA Hunter, JA Savin and MV Dahl. Blackwell Scientific Publications, England, 1989. 272 pages. RRP $56. General practitioners and medical students frequently ask dermatologists to recommend a dermatology book to which they can relate. Many such books are produced but few stand the test of time. "Clinical Dermatology" by Hunter Savin & Dahl is an attempt to reach this market on both sides of the Atlantic. It is jointly written by well-known dermatologists from the University of Edinburgh and the University of Minnesota and in large measures it achieves its aim. The book is well printed with excellent colour photographs. It opens with two introductory
chapters on structure function and immunology of the skin, and finishes with a section on treatment aimed at readers from both the United Kingdon and USA. In the rest of the 272 pages of the book there is a standard treatment of dermatology topics which is up to the minute and which contains useful tables and diagrams and helpful learning points. More emphasis on problem solving would have been of benefit and there is a tendency to include many rare conditions which may add to completeness but in a book of this type creates problems of emphasis. It is likely that this well produced book will have a significant appeal to its target audience. J.A.B. 25
