The Skin Cancer and Sun Knowledge (SCSK) Scale

Abstract

Increasing public knowledge remains one of the key aims of skin cancer awareness campaigns, yet diagnosis rates continue to rise. It is essential we measure skin cancer knowledge adequately so as to determine the nature of its relationship to sun-related behaviors. This study investigated the psychometric properties of a new measure of skin cancer knowledge, the Skin Cancer and Sun Knowledge (SCSK) scale. A total of 514 Western young adults (females n = 320, males n = 194) aged 18 to 26 years completed measures of skin type, skin cancer knowledge, tanning behavior, sun exposure, and sun protection. Two-week test–retest of the SCSK was conducted with 52 participants. Internal reliability of the SCSK scale was acceptable (KR-20 = .69), test–retest reliability was high (r = .83, n = 52), and acceptable levels of face, content, and incremental validity were demonstrated. Skin cancer knowledge (as measured by SCSK) correlated with sun protection, sun exposure, and tanning behaviors in the female sample, but not in the males. Skin cancer knowledge appears to be more relevant to the behavior of young women than that of young males. We recommend that future research establish the validity of the SCSK across a range of participant groups.

Keywords

knowledge skin cancer sun exposure sun protection tanning

Skin cancer remains a significant public health concern in Australia. Despite more than 30 years of public health messages surrounding skin cancer, the diagnosis rate continues to rise (Kasparian, McLoone, & Meiser, 2009). As basal and squamous cell carcinomas are not notifiable diseases in the majority of Australian states and territories it is difficult to obtain an accurate rate of skin cancer incidence; however, it is estimated that there are over 330,000 diagnoses of melanoma and nonmelanoma skin cancers annually (Australian Institute of Health and Welfare, 2011; Cancer Council Australia, 2013). Appropriate sun protection should prevent most cases of skin cancer, yet it is widely reported that people are failing to use, or inconsistently using, sun-protective methods (e.g., Kasparian et al., 2009). The incidence of melanoma also varies by sex and by age; among Australians aged 20 to 24 years, incidence of melanoma was nearly 30% higher in females than in males in 2008 although by age 50 to 59 years incidence of melanoma was almost 16% higher in males, suggesting sex and age differences in risk profile (e.g., Australian Institute of Health and Welfare, 2011).

The specific role of health knowledge in affecting behavior change has been debated across a number of health issues (e.g., smoking and binge drinking; Oncken, McKee, Krishnan-Sarin, O’Malley, & Mazure, 2005; Sandford, 2008). Perspectives vary among researchers regarding the utility of increasing skin cancer knowledge as a means to improving sun-related behaviors. Consequently, many studies that explore determinants of sun-related behaviors do not address skin cancer knowledge. Nonetheless, increasing public knowledge remains one of the key steps in the majority of public health campaigns, and it is essential that we understand the utility of information provision as a correlate of health promoting behavior.

A recent systematic review conducted by the authors of this study found that the relationship between skin cancer knowledge and sun-related behaviors is unclear, and more research is needed (Day, Wilson, Hutchinson, & Roberts, 2013). There appears to be a positive association between sun protection and skin cancer knowledge, and although there are limited data on the link between knowledge and sun tanning, there is some suggestion that the relationship acts in a counterintuitive direction, with skin cancer knowledge positively related to unhealthy tanning behaviors (Choi et al., 2010; Felts, Burke, Vail-Smith, & Whetstone, 2010; Sjöberg, Holm, Ullén, & Brandberg, 2004). The reasons for this are unclear. The recent review also revealed that the vast majority of measures of skin cancer knowledge do not have adequate validity or reliability. It is evident that there is need for research to (a) include skin cancer knowledge as a potential determinant of sun-related behaviors and (b) to measure skin cancer knowledge adequately and consistently.

Although skin cancer knowledge is unlikely to account for all the variance in the three sun-related behaviors linked to skin cancer (sun protection, “incidental” sun exposure, and the “deliberative sun exposure” of outdoor tanning), the construct has not been measured adequately in the past. Health research indicates that knowledge predicts intention to behave and is a necessary precursor to the contemplation of behavior change (Prochaska & Velicer, 1997). We would expect that skin cancer knowledge, should it be measured adequately, would be related to sun-related behaviors. Thus, it is essential that care be taken to measure this relevant construct adequately so as to determine the nature of its relationship to sun-related behaviors.

Study Aims

This study aims to examine the psychometric properties of the Skin Cancer and Sun Knowledge (SCSK) scale—a new, comprehensive measure of skin cancer and sun health knowledge—in young adults of Western background. Due to significant gender differences often found in sun-related behavior research, we will report the results by gender. It is hypothesized that the SCSK will be a valid and reliable measure of skin cancer knowledge. Furthermore, it is hypothesized that skin cancer knowledge (as measured by the SCSK) will be associated with frequency of sun-protective behavior, sun exposure, and outdoor tanning. Last, it is hypothesized that the SCSK will exhibit incremental validity over two existing measures of skin cancer knowledge, that is, the SCSK will explain more variance in frequency of sun-protective behavior, sun exposure, and outdoor tanning than both the single-item measure of skin cancer knowledge “Does the sun cause skin cancer?” as well as recently used knowledge measure (Patel et al., 2010).

Method

Participants

Participants were 514 undergraduate students aged between 18 and 26 (M = 20.60, SD = 2.06), recruited from The University of Adelaide. Using a student sample was appropriate as young adults are considered a high-risk group regarding sun-related behavior practices (Abroms, Jorgensen, Southwell, Geller, & Emmons, 2003; Cafri, Thompson, Jacobsen, & Hillhouse, 2009; Cottrell, McClamroch, & Bernard, 2005). Furthermore, a large proportion of literature in the area uses student populations, making comparisons meaningful (see Day et al., 2013).

Measures

Demographics

Participants were asked to indicate their age, gender, ethnicity, and skin type (as per the Fitzpatrick Classification Scale; Fitzpatrick, 1988). Participants were also asked about their history of skin cancer diagnosis (personal or familial).

Skin Cancer Knowledge

Skin Cancer and Sun Knowledge (SCSK) scale

This scale consists of 25 items that assess skin cancer and sun health knowledge. This measure was developed by the authors following a systematic review of the skin cancer knowledge literature and is based on existing scale items and current best practice research (for further details, see Day et al., 2013). A large proportion of commonly utilized theories of health psychology implicitly recognize the role of knowledge of the disease in perceiving susceptibility and severity, as well as actions that can be taken to reduce risk (e.g., the Health Belief Model, Becker, 1974; the theory of reasoned action, Fishbein & Ajzen, 1975; the transtheoretical model, Prochaska & Velicer, 1997; and the protection motivation theory, Rogers, 1975). Based on this theoretical background, the SCSK was developed to encompass five broad domains of knowledge: sun protection (Items 1, 4-7, 16-22), tanning (Items 2-12), skin cancer risk factors (Items 13-15, 23), prevalence of skin cancer (Items 15, 24), and signs of skin cancer (Item 25). A 25-item, pilot form of the measure was sent to four health professionals with experience in skin cancer research for review and feedback. As a result of this expert review, two items were reworded for clarity. The revised form of the measure was then piloted with 11 postgraduate psychology students, and based on feedback from this stage, a further two items were reworded into the form included in this article. The SCSK scale includes 15 true-false items and 10 multiple-choice items, with a possible score range of 0 to 25; a higher score indicating higher knowledge (see Table 1).

Table 1.

Skin Cancer and Sun Knowledge (SCSK) Scale Items.

1. I should stay out of the sun if my shadow is shorter than my body.	T	F
2. Sunbathing for only a couple of weeks a year (e.g., when on holiday) increases your likelihood of getting skin cancer.	T	F
3. Solariums/sun beds are a safe way to get a tan.	T	F
4. When using sunscreen, you can tan without any negative effects.	T	F
5. Having a tan protects my skin from the sun.	T	F
6. A fake/spray on tan provides me with no protection from the sun.	T	F
7. Keeping your skin tanned at a solarium during the winter protects it from sun damage during the summer.	T	F
8. Gradual tanning eliminates most of the negative effects of lengthy exposure to the sun.	T	F
9. A tan is a sign that the skin is damaged.	T	F
10. UVR (ultraviolet rays) from tanning beds is safer than UVR from the sun.	T	F
11. Tanning is an unsafe way to get the vitamin D your body needs.	T	F
12. A tan is a sign of good health.	T	F
13. If you are not usually exposed to the sun, being severely sunburned two or three times during your life will probably not increase your chances of skin disease.	T	F
14. The only way a person can get skin cancer is from too much exposure to the sun.	T	F
15. People with dark skin cannot get skin cancer.	T	F
16. When should sunscreen be applied for best protection?
a. Just before you go in the sun
b. 15-30 minutes before going in the sun
c. Within 15-30 minutes after going in the sun
17. How often should SPF 30 sunscreen be reapplied?
a. Every 30 minutes
b. Every 2-3 hours and more often if swimming or sweating
c. Neither of these options
18. When is the sun the strongest?
a. 9:00 a.m. to 12:00 p.m.
b. 10:00 a.m. to 4:00 p.m.^a
c. 2:00 p.m. to 5:00 p.m.
19. Damage caused by the sun can be repaired by:
a. After-sun lotions (e.g., Aloe Vera lotion)
b. Moisturizers
c. Both of these options
d. Neither of these options
20. What type of clothing usually blocks more UV radiation (from the sun)?
a. Lighter colored clothing
b. Darker colored clothing
c. Both of these options
d. Neither of these options
21. What does SPF 30 mean?
a. A sunscreen with a SPF of 30 means a person can stay in the sun 30 times longer without burning than he or she could if not wearing sunscreen
b. A sunscreen with a SPF of 30 provides twice as much protection as a sunscreen with a SPF of 15
c. Both of these options
d. Neither of these options
22. Can you get a sunburn . . .
a. In a snowy environment?
b. In an outdoor pool or the ocean?
c. Both of these places
d. Neither of these places
23. Which of the following increases your risk of skin cancer?
a. Having had three severe sunburns in your past
b. Having a family history of skin cancer
c. Both of these options
d. Neither of these options
24. What is the most common form of skin cancer?
a. Melanoma
b. Basal cell carcinoma
c. Squamous cell carcinoma
d. None of these options
25. Which of the following could be a sign of skin cancer?
a. A sudden or gradual change in a mole’s appearance
b. A sore that doesn’t heal
c. Both of these options
d. Neither of these options

Note. Correct answers are shown in boldface. An “I don’t know” option was included for all questions.

Different studies and cancer organizations cite different correct responses to this question (Q18). We have chosen the broadest time frame to allow for seasonal and atmospheric variation. When this study was conducted, Q22 (a) stated “At the snow.” This item has been reworded as a result of subsequent feedback.

Knowledge of Sun Protection Methods (KSPM)

The KSPM (Patel et al., 2010) is a nine-item, true or false measure assessing young adults’ knowledge of sun-protective methods (e.g., “If you apply sunscreen, you only need to apply it once a day”). Higher scores indicate a higher level of knowledge, and total score ranges from 0 to 9. This measure was included to test the incremental validity of the SCSK scale.

Single-item measure

A single, true-false item “Does sun exposure cause skin cancer?” was also included to establish incremental validity of the SCSK. This item has been utilized a number of times in the literature as the sole measure of skin cancer knowledge.

Tanning behavior

Participants were presented with the following definition of outdoor tanning: “Exposing your body to direct sunlight outside for the purpose of tanning your skin.” Participants were then asked to rate on a scale from 0 to 4 the frequency with which they engaged in outdoor tanning behavior over the past few years (never, once or twice, 3-5 times a year [i.e., once every month or two on average], 7-12 times a year [i.e., almost every month on average], more than once a month). As 57.7% of males (n = 112) reported never having deliberately outdoor tanned in this period, we recoded their responses into dichotomous yes/no format.

Sun exposure

This is a 2-item measure assessing participants’ sun exposure (Sun Habits; Glanz et al., 2008) during summer. Participants indicated their average frequency of hours spent outside per day between the hours of 10 a.m. and 4 p.m. on weekdays and weekends during the summer on a 7-point Likert-type scale. These two scores are combined and weighted (by 5 for weekdays and by 2 for weekends, then divided by 7) to enable an average daily sun exposure score ranging from 1 to 7 with higher scores reflecting greater levels of sun exposure.

Sun Protection Behavior Scale (SPBS)

This is a nine-item measure assessing the use of sun-protective behaviors (Weinstock, Rossi, Redding, & Maddock, 2002; Weinstock, Rossi, Redding, Maddock, & Cottrill, 2000) when in the sun for more than 15 minutes (e.g., frequency of wearing hats, time spent in the shade). Participants indicated the frequency with which they practiced sun protection on a 5-point Likert-type scale (never, rarely, sometimes, often, and always) with higher scores reflecting more frequent use of sun-protective behaviors (range was 9 to 45). Cronbach’s alpha for the SPBS has been reported at .83 in a U.S. study of beachgoers aged 12 to 65 (N = 2,324; Weinstock et al., 2000).

Characteristics of the measures used in this study are shown in Table 2.

Table 2.

Descriptive Statistics for the Study Measures Among Participants (N = 514).

		Females (n = 320)			Males (n = 194)
Variable	Number of Items	Mean (SD)	Range	α	Mean (SD)	Range	α
Sun-Protective Behavior	9	29.84 (5.56)	16-43	.76	27.68 (5.71)	13-40	.78
Sun Exposure	2	2.99 (1.33)	1-7	.76	2.82 (1.33)	1-7	.82
Outdoor Tanning	1	1.31 (1.24)	0-4	na	—	—	—
KSPM	9	8.68 (0.65)	6-9	.31^a	8.60 (0.70)	5-9	.30^a
SCSK	25	18.35 (3.12)	8-25	.70^a	18.06 (3.14)	8-24	.67^a

Note. α = Cronbach’s alpha for the present study. α could not be calculated for the Outdoor Tanning variable as it is a single-item measure. KSPM = Knowledge of Sun Protection Methods; SCSK = Skin Cancer and Sun Knowledge.

In the case of both the KSPM and SCSK scales, Kuder Richardson-20 is reported rather than Cronbach’s α because the items are scored dichotomously.

Procedure

On receiving institutional ethics approval, the study was advertised online on the university’s Research Central website to first-year Psychology students and on the university’s intranet home page to all undergraduate students (approximately 37,000 students have access to this page). Due to confidentiality constraints, we were unable to determine an accurate number of eligible first-year psychology students or undergraduate intranet users to calculate response rates. Sixty-four first-year psychology participants agreed to complete a partial retest of the survey (the SCSK scale) at a later date (when electing to participate, participants were unaware which section would be retested), and of these, 52 participated in retesting 2 weeks after the initial survey (retest response rate of 81%). Psychology participants received course credit in exchange for their participation; all other undergraduate student participants went into the draw for one of four $50 shopping vouchers.

Statistical Analysis

IBM SPSS Statistics 20.0 was used for all analyses. Regression analyses included skin type as a predictor of sun-related behaviors.

SCSK Analysis

The SCSK measure was subjected to exploratory factor analysis, using a principal axis extraction method (Fabrigar, Wegner, MacCallum, & Strahan, 1999). Based on the scree plot and Kaiser rule (eigenvalues >1) a single factor solution was retained, and no items were dropped. To evaluate the internal reliability of the SCSK scale, Kuder-Richardson-20 statistics were calculated. Test–retest reliability was assessed at 2 weeks in the subsample described above using Pearson’s product moment correlation.

Predictive Analysis

Preliminary analyses were conducted to ensure no violation of the assumptions of normality, linearity, homoscedasticity, and multicollinearity. One variable (KSPM) was transformed due to kurtosis; however, the subsequent data analysis revealed no significant difference in the results due to transformation, so the original variable was used in the analyses presented. Personal history of skin cancer was not included in the analyses as only n = 2 participants reported an experience. Sequential multiple regression analyses were performed to determine (a) whether the KSPM measure predicted each of the three sun-related behaviors (controlling for relevant variables in the first step) and (b) whether the SCSK scale explains incremental variance in sun-related behavior as compared to the KSPM measure alone. All procedures followed guidelines specified by Tabachnick and Fidell (2007).

Results

Demographic Information

Participants reported their ethnic background as follows; n = 332 (64.6%) Australian, n = 174 (33.8%) European, and n = 8 (1.6%) American. Two participants (0.6%) reported a personal history of skin cancer, with n = 182 (35.4%) reporting a family history. Participants reported their Fitzpatrick Skin Type as follows: n = 127 (24.7%) Skin Type I (fairest), n = 126 (24.5%) Skin Type II, n = 127 (24.7%) Skin Type III, n = 105 (20.4%) Skin Type IV, n = 27 (5.3%) Skin Type V, and n = 2 (0.4%) Skin Type VI (darkest).

Psychometric Analysis of the SCSK Scale

Internal reliability for the SCSK scale was acceptable (KR-20 = .69), and 2-week test–retest reliability was high, r = .83, n = 52 (p < .001). Both face and factorial validity were evidenced (see Method for details). Incremental validity was intended to be tested against the single true–false item “Does sun exposure cause skin cancer?” across the three sun-related behaviors; however, the single knowledge item was not correlated with any of the three sun-related outcomes (see Table 2), making formal regression testing unnecessary. The SCSK demonstrated incremental validity over the KSPM measure in predicting outdoor tanning, sun exposure, and sun protection (see section Knowledge as a Predictor of Sun-Related Behaviors below).

Predictive Analysis

Bivariate correlations among all variables of interest are presented in Table 3.

Table 3.

Intercorrelations Between Demographic, Independent, and Dependent Variables for Females (n = 320) and Males (n = 194).

Variable	1	2	3	4	5	6
Predictor variables
1. Age	1.00 (1.00)	.01 (.01)	.18** (.06)	.15** (.12)	−.19* (−.15*)	−.11 (—)
2. KSPM		1.00 (1.00)	.30 (.20)	.12* (.02)	−.12 (.07)	−.15** (—)
3. SCSK			1.00 (1.00)	.27** (.03)	−.25** (−.01)	−.21** (—)
Outcome variables
4. SBP				1.00 (1.00)	−.21** (−.04)	−.36** (—)
5. Sun Exposure					1.00 (1.00)	.35** (—)
6. Outdoor Tanning						1.00 (—)

Note. KSPM = Knowledge of Sun Protection Methods; SCSK = Skin Cancer and Sun Knowledge; SPB = Sun-Protective Behavior. The correlations are presented for both genders (male correlations are in parentheses).

p < .05. **p < .01.

Females

SCSK scores, F(4, 315) = 3.31, p = .01, sun-protective behavior, F(4, 315) = 5.34, p < .001, average sun exposure, F(4, 315) = 6.73, p < .001, and outdoor tanning, F(4, 315) = 21.32, p < .001, differed significantly as a function of reported skin type. Knowledge measured with the KPSM and age did not differ significantly between skin type groups.

On average, participants who reported a family history of skin cancer had significantly higher SCSK knowledge (M = 18.81, SD = 2.77) than those with no reported family history (M = 18.07, SD = 3.29), t(287) = 2.16, p = .03, Cohen’s d = .26. Those participants who reported a family history of skin cancer reported significantly lower levels of outdoor “deliberative” tanning (M = 1.06, SD = 1.07) than those with no reported family history (M = 1.46, SD = 1.31), t(292) = −2.98, p = .003, Cohen’s d = .34.

Males

Reported age, familial history of skin cancer, and knowledge measured with the KSPM and SCSK did not differ significantly as a function of reported outdoor tanning. As neither of the knowledge measures were associated with sun exposure, sun protection, or outdoor tanning, multiple regression analyses were not performed with this group.

Knowledge as a Predictor of Sun-Related Behaviors (Females)

Sun-Protective Behavior

The total variance explained was 12.3%, F(4, 315) = 11.03, p < .001. The SCSK scale explained an additional 3.6% of the variance in sun-protective behavior, after controlling for age, skin type, and the KSPM measure, F change (1, 315) = 13.00, p < .001. In the final model, only skin type and the SCSK scale were statistically significant.

Sun Exposure

The total variance explained was 13.8%, F(4, 315) = 12.58, p < .001. The SCSK scale accounted for an additional 2.4% of the variance in sun exposure, after controlling for age, skin type, and the KSPM measure, F change (1, 315) = 8.93, p = .003. Age, skin type, and the SCSK scale were statistically significant in the final model.

Outdoor Tanning

The total variance explained was 23.2%, F(4, 315) = 23.84, p < .001. The SCSK scale explained an additional 1.1% of the variance in outdoor tanning, after controlling for skin type, family history of skin cancer, and the KSPM measure, F change (1, 315) = 4.57, p =.03. Skin type and the SCSK scale were statistically significant in the final model.

Raw and standardized regression coefficients of each step of these analyses are presented in Table 4.

Table 4.

Summary of Sequential Multiple Regression Equations Predicting Frequency of Outdoor Tanning, Average Sun Exposure, and Sun-Protective Behavior With Demographic Variables and Skin Cancer Knowledge Measures for Females (n = 320).

	Sun-Protective Behavior			Average Sun Exposure			Frequency of Outdoor Tanning
Variable	B	SE B	β	B	SE B	β	B	SE B	β
Step 1
Age	0.39	0.15	.15**	−0.12	0.03	−.18**	—	—	—
FHx	—	—	—	—	—	—	−0.06	0.27	.07
Skin type	−1.07	0.25	−.23***	0.29	0.06	.26***	0.45	0.05	.44***
Step 2
Age	0.39	0.15	.14**	−0.12	0.03	−.18**	—	—	—
FHx	—	—	—	—	—	—	0.18	0.13	.07
Skin type	−1.04	0.25	−.22***	0.28	0.06	.25***	0.44	0.05	.43***
KSPM	0.88	0.46	.10	−0.20	0.11	−.10	−0.23	0.10	−.12*
Step 3
Age	0.29	0.15	.11*	−0.10	0.03	−.15**	—	—	—
FHx	—	—	—	—	—	—	0.16	0.13	.06
Skin type	−0.91	0.25	−.20***	0.26	0.06	.23***	0.43	0.05	.41***
KSPM	0.38	0.48	.04	−0.10	0.11	−.05	−0.17	0.10	−.09
SCSK	0.37	0.10	.20***	−0.07	0.02	−.17**	−0.04	0.02	−.11*

Note. FHx = Family history of skin cancer, KSPM = Knowledge of Sun-Protective Methods, SCSK = Skin Cancer and Sun Knowledge.

Sun-Protective Behavior: R² = .08 (p < .001) for Step 1, ΔR² = .01 (p = .06) for Step 2, ΔR² = .04 (p < .001) for Step 3. Average Sun Exposure: R² = .10 (p < .001) for Step 1, ΔR² = .01 (p = .07) for Step 2, ΔR² = .02 (p = .003) for Step 3. Frequency of Outdoor Tanning: R² = .21 (p < .001) for Step 1, ΔR² = .02 (p = .02) for Step 2, ΔR² = .01 (p = .03) for Step 3. *p < .05, **p < .01, ***p < .001.

Discussion

The present study examined the psychometric properties of a new, comprehensive measure of skin cancer and sun health knowledge in a sample of young adults of Western background. As hypothesized, in females skin cancer knowledge (as measured by SCSK) was associated with all three sun-related behaviors (i.e., outdoor tanning, sun exposure, and sun-protective behavior). Conversely, skin cancer knowledge was not associated with sun-related behaviors in the male sample.

Psychometric Properties of the SCSK Scale

The 25-item SCSK scale was found to have adequate internal reliability and good 2-week test–retest reliability. Furthermore, face and content validity were established through a rigorous development process outlined above. Due to the centrality of skin cancer knowledge in sun health promotion campaigns and interventions, it is essential that this construct is measured accurately and its relationship with sun-related behaviors be reported. The SCSK scale was found to have much higher internal validity than the KSPM measure (KR-20 = .69 vs. KR-20 = .30). Furthermore, the predictive power of the SCSK was stronger than the KSPM in the female group, correlating with all three sun-related behaviors whereas the KSPM was only associated, minimally, with two (sun-protective behavior and outdoor tanning). The single-item measure of skin cancer knowledge “Does sun exposure cause skin cancer?” was not associated with any of the sun-related behavioral outcomes. Hence, incremental validity was established for the SCSK across all three sun-related behavior outcomes in the female samples. These findings confirm the limitation associated with the use of single-item measures of skin cancer knowledge, the need for skin cancer knowledge to be measured comprehensively, and suggests the utility of the newly developed SCSK scale.

Knowledge as a Predictor of Sun-Related Behaviors

While the SCSK scale was found to be a reliable and valid measure of skin cancer knowledge in young adult males, knowledge (measured by the single-item measure, the KSPM, and the SCSK) was not associated with any of the sun-related behavior outcomes in this group. This suggests that knowledge is not a relevant factor in the sun-related choices of Australian young adult males. Previous studies in the area have almost all failed to report the relationship between skin cancer knowledge and sun-related behaviors by gender, and it may be that the nonassociation in those male groups was inadvertently “hidden” by the often high proportion of females in the sample (see data in Day et al., 2013). In a U.S. sample of male farmers, sun-protective knowledge was associated with behavior (Parrott & Lemieux, 2003); however, this contrasting result may be due to age of participants or the additional occupational UV risk they faced. Our male sample size was fairly modest (n = 194), and future research focusing on males may provide different results. The young males in our sample reported suboptimal levels of sun-protective behavior, and 42.3% reported deliberate outdoor tanning behavior in the past few years. Young adult males spend a lot of time participating in outdoor activities, and research suggests they engage in lower levels of sun-protection than their female counterparts (Buller et al., 2011; Wickenheiser, Baker, Gaber, Blatt, & Robinson, 2013). Given our findings, we recommend that future research explore other factors relevant to sun-related behaviors, such as appearance motivations for tanning and social norms around sun protection, in this at-risk group.

As hypothesized, our measure of skin cancer knowledge (SCSK) was associated with all three sun-related behaviors in the female sample. Sun-protective behavior was positively associated with skin cancer knowledge, with a moderate effect. This result is consistent with results from a recent systematic review (Day et al., 2013). The effect found in this study was of similar size to those found in similar studies (e.g., Castle, Skinner, & Hampson, 1999; De Vries, Lezwijn, Hol, & Honing, 2005; Martin, 1995). Higher levels of skin cancer knowledge were associated with lower levels of sun exposure and outdoor tanning. The strength of both these effects in the present study was moderate. Keesling and Friedman (1987) found a similar relationship for sun exposure in adults of both genders; however, a nonsignificant relationship was reported in a study including participants of mixed gender and unknown age (Berwick, Fine, & Bolognia, 1992). The outdoor tanning finding contrasts with a number of studies that found no significant relationship in a sample of similar age; however, those studies included both males and females (Felts et al., 2010; Keesling & Friedman, 1987; Vail-Smith & Felts, 1993). The comparisons of the findings in this study to previous works need to be considered in light of the measurement differences in skin cancer knowledge. We recommend that future research utilize the SCSK with other samples to establish the generality of the reported relationship between knowledge and behavior.

Previous research has found a number of other predictors of sun-related behaviors. These include appearance motivation and sociocultural influence, perceived risk, and self-efficacy (see reviews by Holman & Watson, 2013; Kasparian et al., 2009; Reynolds, 2007). We recommend that future research measures skin cancer and sun health knowledge in addition to other predictors in order have a more comprehensive understanding of the influence of skin cancer knowledge on sun-related behaviors. It is possible, for example, that skin cancer knowledge moderates the relationship between other predictors, such as self-efficacy, and sun-related behavior.

Limitations

The findings of this study are subject to some limitations. Generalizability is restricted to university students; however, other studies reporting similar information have also used university student samples, which makes research comparisons meaningful. As we were unable to determine an accurate response rate (see Method), sampling bias cannot be ruled out. The study was predominantly focused on testing a new measure of skin cancer and sun health knowledge, and model testing was limited to the inclusion of history of skin cancer and skin type. There are a number of other factors that have been found to be associated with sun-related behaviors, including appearance motivation and unrealistic optimism. Including these variables in multiple regression analyses is likely to give a more complete picture of the influence of skin cancer knowledge on sun-related behaviors.

Last, the appeal of tanned skin is unique to Western cultures, particularly Caucasians, and in a number of Asian cultures pale skin is commonly desired (Hunt, Auguston, Rutten, Moser, & Yaroch, 2012). Culture, therefore, would affect sun-related behaviors, and possibly knowledge. Based on ethnicity data collected, it appears unlikely that a significant portion of our sample would identify as non-Western; however, the lack of an explicit measure of acculturation is a limitation of this work.

Conclusion

Despite the centrality of skin cancer knowledge in prevention campaigns and interventions, many different approaches to its measurement are reported in the literature. There are a number of studies that highlight the importance of continuing to include skin cancer knowledge as a predictor of sun-related behavior and the need for a demonstrably valid and reliable measure (see review by Day et al., 2013). The current results indicate that the 25-item SCSK scale has demonstrated reliability and validity and is associated with sun exposure, outdoor tanning, and sun protection in a group of Western women. We recommend that the SCSK be utilized in future skin cancer and sun tanning research, across a range of participant groups. In the female sample, skin cancer knowledge, skin type, and demographic variables accounted for a fairly modest amount of variance in sun-related behaviors, and in the male sample skin cancer knowledge was not associated with sun-related behaviors. Therefore, continued exploration of other factors is important.

Footnotes

Declaration of Conflicting Interests

The authors declared no potential conflicts of interests with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

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