Sun Protective Behaviors and Attitudes of Runners

Sun exposure is a risk factor for skin cancer. Knowledge and behaviors around sun exposure protective measures are poorly described in athletes including runners. Our primary objective was to describe sun exposure behaviors and knowledge in a population of runners. A cross-sectional online survey was administered to 697 runners to measure the frequency of seven sun protective behaviors: sunscreen use on the face or body; wearing a hat, sunglasses, or long sleeves; running in shade; and avoidance of midday running. Between 54% and 84% of runners reported that they engaged in these behaviors at least sometimes, but only 7% to 45% reported frequent use. Of 525 runners who gave a primary reason for not using sunscreen regularly, 49.0% cited forgetfulness; 17.3% cited discomfort; and only a small percentage cited maintaining a tan (6.1%) or optimizing vitamin D (5.1%). Of 689 runners who responded to a question about what factor most influences their overall sun exposure habits, 39.2% cited fear of skin cancer, 28.7% cited comfort level, and 15.8% cited fear of skin aging. In addition to the seven individual behaviors, we also asked runners how frequently they took precautions to protect against the sun overall. We explored associations between participant characteristics and the overall use of sun protection using ordinal logistic regression. Overall, sun protection was used more frequently in runners who were female, older, or had a history of skin cancer. Runners appear to recognize the importance of sun protection and the potential consequences of not using it, but report forgetfulness and discomfort as the biggest barriers to consistent use. Interventions using habit-formation strategies and self-regulation training may prove to be most useful in closing this gap between knowledge and practice.


Introduction
Skin cancer is a common form of malignancy in the United States. Outdoor athletes such as runners are at increased risk of skin cancer resulting from high sun exposure related to sports participation, especially during peak hours of ultraviolet (UV) radiation [1][2][3][4]. For example, National Collegiate Athlete Association (NCAA) division athletes may experience approximately 1000 h of sun exposure annually [5]. UV exposure results in a dose-and time-dependent induction of DNA damage [6], and sweating may intensify this effect [3]. Further, immunosuppression associated with overtraining syndrome in athletes has been proposed as a risk factor for the development of melanoma [7,8]. Compared with the general population, marathon runners present with more atypical nevi, especially those with highest training intensity [9]. These skin changes have been shown to be indicators of an increased risk for the development of melanoma [10,11].
Sun protective behaviors in the general population were reported in the U.S. National Health and Nutrition Examination Survey 2003-2006 [12]. In this study, 56% of Caucasians self-reported at least moderate (sometimes, most of the time, or always) use of sunscreen,

Materials and Methods
We recruited subjects through the Pacific Association of USA Track and Field organization between January 2010 and March 2011. The association members are primarily from Northern California and part of Nevada. To be eligible, participants were 18 years of age or older and provided online consent prior to participation. The Stanford Institutional Review Board (protocol #17950) approved the research protocol.
The electronic online survey was designed to assess self-reported frequency and influence of behaviors related to sun protection, graded in categories with ability to select one response per question: never, seldom, sometimes, almost always, and always. Participants were asked about their use of 7 individual sun protective behaviors (wearing sunglasses, sun hat, or long sleeves; using sunscreen on the body or face; avoiding midday running; and running in the shade) as well as their use of sun protection overall (e.g., taking some precaution) when running outdoors during daylight hours. Additionally, subjects were asked to choose their primary reason for not using sunscreen if they do not use sunscreen regularly (from a menu of 7 choices), and they were asked to choose a primary influence on their sun exposure habits (from a menu of 5 choices). The questions are included in an Appendix A.
For descriptive purposes, we report frequencies and percentages in three categories: rare (never or seldom), sometimes, and frequent (almost always and always). We also created a composite variable of the 7 individual behaviors using principal components analysis. We calculated the Pearson's correlation coefficient between this composite variable and the overall question to check for consistency. To explore the associations between participant characteristics and overall use of sun protection, we used ordinal logistic regression and included all 5 ordinal categories. We additionally used multiple linear regression to explore the associations between the participant characteristics and the composite of the 7 individual sun protective behaviors.

Participants
In total, 697 runners (406 women and 291 men) participated in the study. At time of survey completion, runners were 42.3 ± 13.1 years old, ran 37.4 ± 17.7 miles per week in the past year, and had a body mass index of 21.9 ± 2.6 kg/m 2 . The full data set and statistical code is available as Supplementary File S1 and Supplementary Table S1.

Sun Protective Behaviors
The majority of runners reported using each of the seven assessed sun protective behaviors at least sometimes (Table 1); however, less than half reported frequent use (always or almost always) of each of the behaviors. Runners were most likely to frequently use sunglasses (45%), and least likely to frequently wear long sleeves (7%). Facial protection (sunglasses, facial sunscreen, hat) was more consistently used than full-body protection (sunscreen on the body, long sleeves). Table 1. Runners' frequency of use of sun protective behaviors while running. Frequent includes "always" or "almost always" and rare includes "never" or "seldom".

Behavior Frequent Sometimes Rare
Wear Sunglasses 45% 25% 30% Avoid mid-day sun exposure ( A separate question characterized the primary reason for not using sunscreen while running. Of 525 runners who responded to this question, most cited forgetfulness (49%) or discomfort (17.3%), and only a small percentage cited maintaining a tan (6.1%) or optimizing vitamin D (5.1%) ( Table 2). In total, 689 runners responded to a question about what factor most influences their overall sunscreen use and 39.2% cited fear of skin cancer, 28.7% cited comfort level, and 15.8% cited fear of skin aging (Table 3).

Factors Associated with Overall Use of Sun Protection
On the overall use of sun protection question, only 36% of runners reported frequently using sun protection, 35% reported sometimes using, and 29% reported rarely using. The composite measure of the seven individual behaviors using principal components analysis resulted in correlation between the overall sun protection question and this composite measure was 0.74.
We explored the association between participant characteristics and the frequency of use of sun protection. In univariable analyses, use of any sun protection was more frequent among females (p < 0.001), older runners (p = 0.008), those who ran fewer miles per week (p = 0.018), those with lower BMI (p = 0.007), and those who had a history of skin cancer (p < 0.001) (Table 4). However, mileage and BMI were no longer significant after adjusting for gender and age. A final multivariable model included: female gender (OR = 2.93, p < 0.001); older age (OR = 1.02 per year, p = 0.005); and a history of skin cancer (OR = 3.39, p < 0.001). In a multiple linear regression model that used the composite variable as the dependent variable, age, female gender, and history of skin cancer were also all robust predictors (p < 0.001 for all three variables).

Discussion
This study adds to limited knowledge on sun protective behaviors and attitudes among runners. A majority of runners used each of the seven sun protective behaviors at least sometimes. These rates are higher than have been reported in previous surveys of collegiate runners [5], other collegiate athletes [16], or in the general U.S. population [12]. Our population also appeared to be knowledgeable about the potential risks of sun exposure, identifying concerns for skin cancer or skin aging as the primary influence of their sun exposure behavior. However, a minority of runners reported frequent use of each of the seven sun protective behaviors or reported regular use of some form of sun protection.
Thus, there appears to be a gap between knowledge and practice. Forgetfulness, discomfort, and inconvenience may be reasons for inconsistent use. Runners reported more consistent use for facial protection (facial sunscreen, hat, sunglasses) than for full-body protection (sunscreen on all exposed areas, wearing long sleeves).
Runners who were most likely to engage in sun protection included women, older runners, and those with history of skin cancer. The finding that women and older runners were more likely to use sun protection is consistent with prior reports [13,17,18]. It is also not surprising to identify that those with history of skin cancer reported greater sun protection behaviors. Similar to previous studies [5,13,18,19], we found less consistent sun protective use in males and younger runners, which suggests that intervention efforts that target these populations are needed.
Increases in knowledge about sun protection are not always tied to improvements in those behaviors [20]. Simple and effective methods that increase accessibility have been shown to increase sunscreen use, such as improved availability [16,21], text-message reminders [22], appearance-based interventions [23] (e.g., being shown a personal ultraviolet facial photograph) [24][25][26]. Our results similarly suggest that interventions that address issues of forgetfulness, comfort, and convenience may be effective. Further, the benefits of habit formation strategies and self-regulation training are a promising area of current research [27].
We note that the reported frequency of the overall use of sun protection is lower than the reported use of some specific individual behaviors (such as use of sunglasses). This may reflect differences in recall when asked to report an overall behavior versus individual behaviors. Runners may also engage in some protective behaviors for reasons other than sun protection; for example, they may wear sunglasses for visibility or appearance reasons. However, our sub-analysis does suggest good correspondence between the overall question and individual behaviors, suggesting internal validity of survey responses and that our survey is likely capturing the most common sun exposure protection strategies employed by runners.
While this is the largest study to understand health behaviors in recreational runners in the United States, we do recognize study limitations. We recruited from a running organization primarily based in Western United States with high sun exposure; thus, behaviors in our population may not be generalizable to runners in regions with different sun exposure. Further limitations may result from use of a convenience sample and selfreported behaviors. There is no established questionnaire on sun behaviors in runners and we did not validate our survey measures. To account for this, we measured individual responses to sun exposure behaviors to overall use of some form of sun protection and found strong agreement on principle component analysis. We collected responses in a finite time period and cannot verify whether more recent behaviors around sun protection have changed. Despite these limitations, our findings are novel in an understudied population and suggest runners may benefit from further efforts to reduce risks with sun exposure and develop further measures to evaluate changes in behavior that promote health.

Conclusions
Runners in this population fail to consistently use sun protection despite apparent recognition of the importance and potential consequences of not using it, reporting forgetfulness and discomfort as the biggest barriers to consistent use. Interventions utilizing habit-formation strategies and self-regulation training may prove to be most useful in closing this gap between knowledge and practice.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during daylight hours. How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Never How often do you wear sunscreen on all exposed skin? Statistical code for analysis, Statistical code for analysis, Table S1: Deiden Author Contributions: Conceptualization an ware and formal analysis K.L.S.; writing-o editing A.S.T., M.F., K.E.S.T. and K.L.S. All a of the manuscript. closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, File S1: Statistical code for analysis, Table S1: Deidentified data from participants. Funding: This research received no external funding.

Institutional Review Board Statement:
The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board of Stanford University (protocol #17950).

Informed Consent Statement:
Informed consent was obtained from all subjects involved in the study.

Data Availability Statement:
Deidentified data used in the study, as well as code for reproducing the statistics in the paper, are available in the supplement of this paper. Always closing this gap between knowledge and practice.

Appendix A. Questionnaire on Sun Exposure Behaviors
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, Fi Statistical code for analysis, Table S1: Deidentified data from participants.
Author Contributions: Conceptualization and methodology A.S.T., M.F., K.E.S.T. and K.L.S. ware and formal analysis K.L.S.; writing-original draft preparation A.S.T.; writing-review editing A.S.T., M.F., K.E.S.T. and K.L.S. All authors have read and agreed to the published ve of the manuscript.
Funding: This research received no external funding.

Institutional Review Board Statement:
The study was conducted according to the guidelines Declaration of Helsinki, and approved by the Institutional Review Board of Stanford Univ (protocol #17950).

Informed Consent Statement:
Informed consent was obtained from all subjects involved i study.
Data Availability Statement: Deidentified data used in the study, as well as code for reprod the statistics in the paper, are available in the supplement of this paper. recognition of the importance and potential consequences of not using it, reporting forgetfulness and discomfort as the biggest barriers to consistent use. Interventions utilizing habit-formation strategies and self-regulation training may prove to be most useful in closing this gap between knowledge and practice.

Appendix A. Questionnaire on Sun Exposure Behaviors
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, File S1: Statistical code for analysis, Table S1: Deidentified data from participants. Always recognition of the importance and potential consequences of not using it, reporting getfulness and discomfort as the biggest barriers to consistent use. Interventions util habit-formation strategies and self-regulation training may prove to be most usef closing this gap between knowledge and practice. recognition of the importance and potential consequences of not getfulness and discomfort as the biggest barriers to consistent use. habit-formation strategies and self-regulation training may prov closing this gap between knowledge and practice. Sometimes recognition of the importance and potential conseq getfulness and discomfort as the biggest barriers to habit-formation strategies and self-regulation train closing this gap between knowledge and practice.

Conclusions
Runners in this population fail to consistently use sun protection despite apparent recognition of the importance and potential consequences of not using it, reporting forgetfulness and discomfort as the biggest barriers to consistent use. Interventions utilizing habit-formation strategies and self-regulation training may prove to be most useful in closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, File S1: Statistical code for analysis, Table S1: Deidentified data from participants. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.

Data Availability Statement:
Deidentified data used in the study, as well as code for reproducing the statistics in the paper, are available in the supplement of this paper.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during daylight hours. How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Never How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently use sun protection despite app recognition of the importance and potential consequences of not using it, reporting getfulness and discomfort as the biggest barriers to consistent use. Interventions util habit-formation strategies and self-regulation training may prove to be most usef closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, Fi Statistical code for analysis, Table S1: Deidentified data from participants. Informed Consent Statement: Informed consent was obtained from all subjects involved i study.

Data Availability Statement:
Deidentified data used in the study, as well as code for reprod the statistics in the paper, are available in the supplement of this paper.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during daylight hours. How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Never How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently use sun prote recognition of the importance and potential consequences of not getfulness and discomfort as the biggest barriers to consistent use. habit-formation strategies and self-regulation training may prov closing this gap between knowledge and practice.

Data Availability Statement:
Deidentified data used in the study, as wel the statistics in the paper, are available in the supplement of this paper.

Acknowledgments:
We are grateful to the Pacific Association USA Track Herman for her support of our study, and are grateful for all participant possible. We acknowledge efforts by Adam Daoud for preliminary analys

Conflicts of Interest:
The authors declare no conflict of interest.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Ne How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently recognition of the importance and potential conseq getfulness and discomfort as the biggest barriers to habit-formation strategies and self-regulation train closing this gap between knowledge and practice.

Conclusions
Runners in this population fail to c recognition of the importance and poten getfulness and discomfort as the biggest habit-formation strategies and self-regu closing this gap between knowledge and Supplementary Materials: The following ar Statistical code for analysis, Table S1

Conclusions
Runners in this population fail to consistently use sun protection despite apparent recognition of the importance and potential consequences of not using it, reporting forgetfulness and discomfort as the biggest barriers to consistent use. Interventions utilizing habit-formation strategies and self-regulation training may prove to be most useful in closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, File S1: Statistical code for analysis, Table S1: Deidentified data from participants.

Informed Consent Statement:
Informed consent was obtained from all subjects involved in the study.

Data Availability Statement:
Deidentified data used in the study, as well as code for reproducing the statistics in the paper, are available in the supplement of this paper.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during daylight hours. How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Never How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently use sun protection despite app recognition of the importance and potential consequences of not using it, reporting getfulness and discomfort as the biggest barriers to consistent use. Interventions util habit-formation strategies and self-regulation training may prove to be most usef closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, Fi Statistical code for analysis, Table S1: Deidentified data from participants. Institutional Review Board Statement: The study was conducted according to the guidelines Declaration of Helsinki, and approved by the Institutional Review Board of Stanford Univ (protocol #17950).

Informed Consent Statement:
Informed consent was obtained from all subjects involved i study.

Data Availability Statement:
Deidentified data used in the study, as well as code for reprod the statistics in the paper, are available in the supplement of this paper.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during daylight hours. How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Never How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently use sun prote recognition of the importance and potential consequences of not getfulness and discomfort as the biggest barriers to consistent use. habit-formation strategies and self-regulation training may prov closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.m Statistical code for analysis, Table S1: Deidentified data from participants Data Availability Statement: Deidentified data used in the study, as wel the statistics in the paper, are available in the supplement of this paper.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Ne How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently recognition of the importance and potential conseq getfulness and discomfort as the biggest barriers to habit-formation strategies and self-regulation train closing this gap between knowledge and practice.

Conclusions
Runners in this population fail to c recognition of the importance and poten getfulness and discomfort as the biggest habit-formation strategies and self-regu closing this gap between knowledge and Supplementary Materials: The following ar Statistical code for analysis, Table S1

Conclusions
Runners in this population fail to consistently use sun protection despite apparent recognition of the importance and potential consequences of not using it, reporting forgetfulness and discomfort as the biggest barriers to consistent use. Interventions utilizing habit-formation strategies and self-regulation training may prove to be most useful in closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, File S1: Statistical code for analysis, Table S1: Deidentified data from participants.  Data Availability Statement: Deidentified data used in the study, as well as code for reproducing the statistics in the paper, are available in the supplement of this paper.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during daylight hours. How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Never How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently use sun protection despite app recognition of the importance and potential consequences of not using it, reporting getfulness and discomfort as the biggest barriers to consistent use. Interventions util habit-formation strategies and self-regulation training may prove to be most usef closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, Fi Statistical code for analysis, Table S1: Deidentified data from participants.

Institutional Review Board Statement:
The study was conducted according to the guidelines Declaration of Helsinki, and approved by the Institutional Review Board of Stanford Univ (protocol #17950).

Informed Consent Statement:
Informed consent was obtained from all subjects involved i study.

Data Availability Statement:
Deidentified data used in the study, as well as code for reprod the statistics in the paper, are available in the supplement of this paper.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during daylight hours. How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Never How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently use sun prote recognition of the importance and potential consequences of not getfulness and discomfort as the biggest barriers to consistent use. habit-formation strategies and self-regulation training may prov closing this gap between knowledge and practice.

Institutional Review Board Statement:
The study was conducted accordi Declaration of Helsinki, and approved by the Institutional Review Boar (protocol #17950).

Informed Consent Statement:
Informed consent was obtained from all study.

Data Availability Statement:
Deidentified data used in the study, as wel the statistics in the paper, are available in the supplement of this paper.

Appendix A. Questionnaire on Sun Exposure Behaviors
Answer questions for times when you are running outside during How often do you wear sunscreen on your face?

Always
Almost always Sometimes Seldom Ne How often do you wear sunscreen on all exposed skin?

Conclusions
Runners in this population fail to consistently recognition of the importance and potential conseq getfulness and discomfort as the biggest barriers to habit-formation strategies and self-regulation train closing this gap between knowledge and practice.

Conclusions
Runners in this population fail to c recognition of the importance and poten getfulness and discomfort as the biggest habit-formation strategies and self-regu closing this gap between knowledge and Supplementary Materials: The following ar Statistical code for analysis, Table S1

Conclusions
Runners in this population fail to consistently use sun protection despite apparent recognition of the importance and potential consequences of not using it, reporting forgetfulness and discomfort as the biggest barriers to consistent use. Interventions utilizing habit-formation strategies and self-regulation training may prove to be most useful in closing this gap between knowledge and practice.
Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, File S1: Statistical code for analysis, Table S1: Deidentified data from participants. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.

Data Availability Statement:
Deidentified data used in the study, as well as code for reproducing the statistics in the paper, are available in the supplement of this paper.