Background
Skin cancer is the most common form of cancer, with over a million new cases diagnosed annually in the United States [
1]. The prevalence of melanoma, the deadliest form of skin cancer, has been increasing over the past 30 years [
2] and is now the second most common cancer among women in their twenties [
3]. However, skin cancers are largely preventable with engagement in recommended protective practices, such as limiting ultraviolet radiation (UV) exposure, wearing sun-protective clothing, and using sunscreen. Long-term use of sunscreen is associated with decreased risk of non-melanoma skin cancers [
4]. Results of research studies examining the association between sunscreen use and melanoma risk have been mixed [
4,
5]. However, these studies have typically been limited by a number of methodological issues, including retrospective reports of sunscreen use and the use of non-randomized designs. The results of a recent prospective randomized controlled trial of sunscreen use found a lower incidence of invasive melanoma among individuals assigned to a sunscreen intervention compared to those in the control condition [
6]. Promoting routine sunscreen use as a component of skin protection is a critical aspect of public health approaches designed to reduce the incidence of skin cancer [
7].
Skin protection is especially important for children and adolescents. Early intense exposure to UV radiation is associated with higher rates of skin cancer [
8‐
12], and regular sunscreen use during childhood and adolescence could reduce lifetime incidence of non-melanoma skin cancers by approximately 78% [
13]. Adolescence, in particular, is a critical period for skin cancer prevention because adolescents and young adults have the lowest skin protection rates of all age groups [
14], receive large amounts of UV radiation [
15‐
17], and increase their UV exposure habits as they move into adulthood and are less influenced by their parents [
10,
18]. In 2003, only 14% of US high school students reported routine sunscreen use [
19]. In some cases, higher risk adolescents are less likely to protect their skin. For example, White Hispanic high school students in Miami, Florida were twice as likely to never or rarely wear sunscreen as non-White Hispanics [
20]. While several interventions have been found to produce short-term increases in sunscreen use among children, their long-term effect among adolescents is questionable [
18]. Thus, it is important to better understand the factors underlying adolescents' use of sunscreen and other skin protection behaviors so that we can intervene more effectively with those at highest-risk of developing skin cancer.
Fishbein's Integrative Model (IM; [
21]) provides a comprehensive theoretical framework to describe the relationships among variables predicting adolescents' skin protection intentions and behavior. Drawing from several empirically-validated health behavior theories, the IM includes multiple categories of predictor variables, including: background/individual difference variables, beliefs, norms, self-efficacy, intentions, contextual factors, and behavior. The beliefs category includes behavioral outcome beliefs, defined as beliefs about the consequences of performing the behavior (i.e., what will happen if I apply sunscreen), and outcome evaluations, defined as subjective evaluations or favorability of these consequences. Norms can include prototypes (evaluation of the typical person who engages in the behavior) and subjective norms (the extent to which associates engage in the behavior), as well as motivation to comply with these norms. Self-efficacy includes perceived control over the behavior and self-efficacy to perform the behavior. Contextual factors include environmental cues to engaging in the behavior. These beliefs, norms, self-efficacy, and cues contribute to behavioral intentions, which in turn influence behavior.
Prior research studies have identified associations between adolescent skin protection including sunscreen use and several variables drawn from the IM; however, no prior study has evaluated the full IM within the same study and sample. In terms of
background and individual difference variables, factors that have been found to be associated with greater sunscreen use among adolescents include white race, female gender, younger age, higher skin sensitivity, greater knowledge of sun protection recommendations, and a family history of skin cancer [
22‐
25].
Behavioral beliefs associated with adolescent sunscreen use include a preference for natural/light skin, greater perceived benefits of sun protection, believing that it is not worth burning to get a tan, and perceiving shorter sun exposures as "safer" than longer ones [
24].
Normative factors linked with adolescents' use of sunscreen include sunscreen information and modeling by friends, parental information provision and insistence on sunscreen use, and receipt of sun protection advice from health care providers [
24].
Self-efficacy for skin protection is one of the variables that has been found to be most strongly associated with engagement in skin cancer protection, including among adolescents and young adults [
26‐
29]. Perceived behavioral control over skin protection has also been found to be associated with skin protection [
30]. No prior study has examined the association between sunscreen use and sunscreen-related
cues or availability. The only IM construct that we did not include in this study was skills, since we did not expect there to be much variability in perceived skill level for sunscreen application. Among adolescents and young adults, skin protection
intentions are associated with skin protection
behaviors including sunscreen use [
31‐
35].
The purpose of the current study was to determine which of the IM constructs are most closely associated with sunscreen use among adolescent high school students. Based on prior research, we expected that background/individual differences, beliefs, norms, and self-efficacy would all contribute to adolescent sunscreen use. However, in the current study, we included several novel variables within these domains that have not been investigated previously among high school students. These variables included beliefs about general health (i.e., health consciousness), sunscreen user prototype, as well as body image self-efficacy and emotional coping self-efficacy. Additionally, although not previously included in sun protection research, we expected cues and availability to be related to sunscreen use. Finally, we expected that intentions to use sunscreen would mediate the relationships between the IM variables and sunscreen use.
Results
The characteristics of the study sample are shown in Table
1. The participants were 59% female and 86% non-Hispanic white. Almost half of the students reported knowing at least one person who had been diagnosed with skin cancer. Knowledge of skin cancer and its prevention was moderately high, with an average score of 4.36 correct out of the six items. The mean score on the intentions to use sunscreen measure was 3.46 (on a 1 to 7 scale) and the standard deviation was 1.45. For the measure of sunscreen use (which used a 1 to 5 scale), the mean and standard deviation were 2.86 and 1.04, respectively. The correlation between sunscreen intentions and use of sunscreen was
r = .49 (
p < .001). The results of the regression analyses examining correlates of sunscreen use are shown in Table
2 and summarized in the following sections.
Table 1
Characteristics of Study Sample (N = 242)
Sex | |
Male | 40.9 |
Female | 59.1 |
High school grade | |
9th
| 38.8 |
10th
| 5.0 |
11th
| 26.0 |
12th
| 30.2 |
Race/ethnicity | |
Hispanic | 5.4 |
Non-Hispanic white | 86.4 |
Non-Hispanic Asian | 3.7 |
Non-Hispanic black | 1.2 |
Non-Hispanic other | 3.3 |
Fitzpatrick skin type | |
I | 11.6 |
II | 12.5 |
III | 18.3 |
IV | 34.9 |
V | 17.8 |
VI | 5.0 |
Number of people know with skin cancer | |
0 | 52.5 |
1 | 43.8 |
2 | 3.3 |
3 | 0.4 |
Knowledge of skin cancer and its prevention (M = 4.36, SD = 1.47) | |
0 | 2.9 |
1 | 2.1 |
2 | 5.8 |
3 | 13.6 |
4 | 21.5 |
5 | 29.8 |
6 | 24.4 |
Table 2
Multiple Linear Regression Analyses and Bootstrapping Tests of Indirect Effects of Correlates of Sunscreen Use
Demographics and Individual Differences | .17 | | | |
Sexa
| | -0.38 (-0.64, -0.12) | .004 | -0.14 (-0.28, -0.02) |
High school grade | | -0.05 (-0.15, 0.04) | .291 | |
Raceb
| | 0.03 (-0.36, 0.42) | .891 | |
Fitzpatrick skin type | | -0.25 (-0.35, -0.16) | < .001 | -0.08 (-0.14, -0.03) |
Know someone diagnosed with skin cancer | | -0.10 (-0.36, 0.16) | .429 | |
Knowledge of skin cancer and its prevention | | 0.06 (-0.03, 0.14) | .187 | |
Behavioral Beliefs and Outcome Evaluations | .34 | | | |
Sunscreen benefits | | 0.58 (0.41, 0.74) | < .001 | 0.13 (0.06, 0.23) |
Importance of protecting skin | | 0.28 (0.18, 0.39) | < .001 | 0.07 (0.03, 0.14) |
Perceived risk of skin cancer/premature aging | | 0.11 (-0.01, 0.23) | .069 | |
Perceived severity of skin cancer/premature aging | | 0.05 (-0.10, 0.20) | .523 | |
Appearance orientation | | 0.10 (-0.07, 0.26) | .264 | |
Health consciousness | | -0.03 (-0.16, 0.10) | .640 | |
Normative Beliefs | .12 | | | |
Sunscreen user prototype | | 0.15 (0.04, 0.27) | .008 | 0.04 (-0.01, 0.10) |
Tanning norms | | -0.01 (-0.19, 0.18) | .954 | |
Skin protection norms | | 0.01 (0.01, 0.02) | < .001 | 0.005 (0.002, 0.009) |
Self-Efficacy | .30 | | | |
Perceived behavioral control | | 0.09 (0.02, 0.17) | .019 | 0.00 (-0.02, 0.02) |
Sunscreen self-efficacy | | 0.50 (0.37, 0.62) | < .001 | 0.17 (0.08, 0.29) |
Body image self-efficacy | | -0.15 (-0.29, 0.00) | .044 | -0.01 (-0.06, 0.03) |
Emotional coping self-efficacy | | 0.02 (-0.02, 0.05) | .247 | |
Sunscreen Cues and Availabilityc
| .28 | | | |
Expected to wear it by parents/guardians | | 0.41 (0.07, 0.75) | .018 | 0.15 (0.02, 0.33) |
Always bring some | | 0.73 (0.44, 1.01) | < .001 | 0.19 (0.07, 0.35) |
Purposely brought some | | 0.20 (-0.08, 0.47) | .161 | |
Happened to have some | | -0.18 (-0.42, 0.07) | .165 | |
Borrowed some from someone else | | 0.08 (-0.17, 0.32) | .535 | |
Bought some because it was convenient to buy | | 0.33 (-0.02, 0.69) | .068 | |
Bought some because it was inexpensive | | 0.06 (-0.28, 0.40) | .737 | |
Correlates of Sunscreen Use: Demographic and Individual Difference Variables
Among the demographic and individual difference variables, greater use of sunscreen was reported by female students and those with more sensitive skin. As shown in the final column of Table
2, each of these associations was mediated by sunscreen intentions, such that female students and those with more sensitive skin had higher sunscreen intentions, which in turn were positively associated with sunscreen use. Sunscreen use was not associated with high school grade, race, knowing someone with skin cancer, or knowledge of skin cancer and its prevention.
Correlates of Sunscreen Use: Behavioral Beliefs and Outcome Evaluations
Individuals with stronger perceptions of sunscreen benefits or importance of protecting their skin were more likely to use sunscreen. Each of these associations was mediated by sunscreen intentions, with higher intentions among those reporting greater perceived sunscreen benefits or importance of skin protection. Sunscreen use was not associated with the perceived risk or severity of skin cancer and premature aging, appearance orientation, or health consciousness.
Correlates of Sunscreen Use: Normative Beliefs
Students who had stronger skin protection norms or a more positive sunscreen user prototype reported greater sunscreen use. The association between skin protection norms and sunscreen use was mediated by sunscreen intentions, such that intentions were higher among those with stronger skin protection norms. Tanning norms were not associated with sunscreen use.
Correlates of Sunscreen Use: Self-Efficacy
Students reported greater sunscreen use if they had a higher level of perceived behavioral control over skin protection or sunscreen self-efficacy, or a lower level of body image self-efficacy. The association between sunscreen self-efficacy and sunscreen use was mediated by sunscreen intentions, with higher intentions among those with greater sunscreen self-efficacy. Emotional coping self-efficacy was not associated with sunscreen use.
Correlates of Sunscreen Use: Sunscreen Cues and Availability
Of the sunscreen cues and availability variables examined, students reported greater sunscreen use if they indicated that they were expected to wear it by their parents/guardians or if they always bring some with them when planning to be out in the sun. Each of these associations was mediated by sunscreen intentions, such that intentions were higher among individuals endorsing each item. Sunscreen use was not associated with the remaining sunscreen cues and availability variables examined.
Discussion
The current study consisted of a survey of sunscreen use and its potential correlates among high school students. Consistent with the IM and prior research, sunscreen use was associated with female gender, greater perceived skin sensitivity, higher perceived sunscreen benefits, higher skin protection importance, stronger skin protection norms, greater perceived skin protection behavioral control, and higher sunscreen self-efficacy [
23,
24,
26,
28,
62‐
65]. Prior studies have found sunscreen use to be associated with race and age, but not necessarily in consistent directions [
22,
23,
66]. In the current study, there may not have been enough variability or a large enough sample of certain subgroups to identify such associations. We did not find sunscreen use to be associated with knowledge of skin cancer, knowing someone with skin cancer, perceived risk or severity of skin cancer and premature aging, appearance or health orientation, tanning norms, or emotional coping self-efficacy as it has been in some prior reports [
23,
25,
66]. Overall, sunscreen use was more likely to be associated with positive attitudes and normative beliefs about sunscreen use and skin protection as opposed to negative attitudes toward skin cancer or photo-aging risks. One prior study found that gain-framed messages had a greater impact on increasing sunscreen use among beachgoers than loss-framed messages [
67].
A novel finding of the study is the association of adolescent sunscreen use with a more favorable sunscreen user prototype. A prototype refers to an "image" norm (i.e., appeal of sunscreen users) as opposed to a "statistical" norm (i.e., how many of my friends wear sunscreen). Further exploration of perceived positive and negative characteristics of typical sunscreen users could be informative. Additionally, future research should explore whether role modeling and portraying sunscreen users as appealing could enhance skin protection interventions.
Interestingly, sunscreen use was associated with a low level of body image self-efficacy. Adolescents and young adults experience considerable pressure to appear tan and attractive [
62,
68,
69]. Due to these societal norms for tan skin, body image self-efficacy may be lower among individuals with fair skin who cannot tan effectively and who must use sunscreen or other skin protection more often than others in order to prevent sunburns. On the other hand, individuals who can tan may do so in order to improve their body image. Thus, they may wear sunscreen more frequently simply because they are more frequently exposed to the sun. In a study of patients with body dysmorphic disorder, twenty-five percent reported tanning to address their body image concerns [
70]. Additionally, low perceived physical attractiveness was found to be 'associated with indoor tanning among Swedish adolescents [
71]. Thus, a focus on body image may be an important component of skin protection interventions for adolescents. Emotional coping self-efficacy was not associated with sunscreen use in the current sample, suggesting that skin exposure and protection are separate constructs rather than two ends of a continuum.
In terms of contextual factors, we found that always carrying sunscreen and parental expectations for wearing sunscreen were associated with sunscreen use among students. However, most of the sunscreen contextual items were not significantly associated with sunscreen use. The items that were significantly associated with sunscreen use pertained to norms and habits as opposed to availability and convenience, which may be important distinctions for future intervention efforts.
We found variables from all of the IM [
22] construct categories to be associated with sunscreen use. Consistent with some prior research [
27,
33,
66], most of the statistically significant associations between the correlates and sunscreen use were mediated by intentions. However, the relationships between sunscreen use and sunscreen user prototype, skin protection behavioral control, and body image self-efficacy were not mediated by intentions. This suggests that these correlates may be more proximal determinants of sunscreen use or that their associations may be mediated by factors other than sunscreen intentions. For example, adolescents may emulate the behavior of an appealing prototypical sunscreen user because they perceive him/her to be smart, attractive, and so on, but this may not necessarily be mediated by sunscreen intentions per se. Future research, particularly longitudinal studies, is warranted to examine this issue.
Strengths of the current study include the use of the IM as a comprehensive conceptual framework and inclusion of several novel correlates not previously examined in the context of skin cancer prevention. Limitations include the use of a sample of students from a single high school, the cross-sectional design which limits our ability to make causal inferences from the mediational analyses, and self-report of sunscreen use. However, most skin cancer prevention studies use self-report measures, and several studies have demonstrated the internal and test-retest reliability and criterion and concurrent validity of self-report skin protection behavior compared to observation and objective measures, with no systematic bias identified among various populations [
72‐
74]. Participants may have had some difficulty accurately recalling summer sunscreen use in April; however, this factor was consistent across participants. The lecture may have affected the extent to which students endorsed some of the questionnaire items due to social desirability or a change in beliefs about skin cancer or sunscreen use. However, all students who took the survey had been exposed to the lecture, and the lecture would not be expected to influence the relationship among the variables, which was the primary focus of the study.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
CJH was responsible for data acquisition. EJC was responsible for data analysis. Both authors made substantial contributions to conception and design as well as interpretation of data; were involved in drafting the manuscript and revising it critically for important intellectual content; and have given final approval of the version to be published.