Prevalence and Predictors of the Use of Sunscreen Amongst Medical Students: A Multi-center Cross-sectional Study

Objective Sun exposure is a primary preventable risk factor for skin cancer. Sunscreen has been shown to reduce the risk of certain skin cancers such as squamous cell carcinoma and melanoma. We aimed to assess the prevalence and predictors of sunscreen use among medical students in Karachi. Methods A multi-center cross-sectional study was conducted among 578 students from multiple medical universities in Karachi, Pakistan. The levels of use of sunscreen were recorded using a comprehensive questionnaire consisting of 29 questions. Descriptive statistics were used and p-values less than 0.05 calculated using the chi-square test were considered significant. Results A majority (n=441, 73.9%) of the participants in this study were female students. Sunscreen use was prevalent in 415 (69.5%) participants. Female students were more aware of the risk of skin cancer from extended sun exposure (n=186, 72.4%). Sunscreen use was significantly associated with gender (p<0.001) and the propensity to get sunburned easily (p=0.001). Few (n=19, 5.0%) students reported being well-versed regarding skin cancer and its risk factors. Most participants were aware of the use of sunscreen for sunburn prevention (n=473, 79.2%), though knowledge of the additional benefits of sunscreen, such as the prevention of skin cancer (n=257, 43.0%) and aging (n=199, 33.3%), was lacking. Conclusion There is an evident lack of knowledge of the importance of sunscreen protection among medical students, particularly regarding the prevention of skin cancer and skin aging. However, an overall positive attitude was observed regarding the use of sunscreen among female students. Medical students are an imperative part of our future healthcare system and should be adequately informed on sunscreen benefits and skin cancer prevention.


Introduction
Skin cancer is regarded as one of the most common types of cancer globally, with an especially high incidence rate amongst fair-skinned individuals. Although the incidence rate of skin cancer is significantly lower amongst Africans, Asians and those of Latin American, or American-Indian descent, it manifests with significant mortality due to the atypical presentations of these cases [1]. Of particular concern is the fact that there have been increasing occurrences in both melanoma and non-melanoma skin cancers worldwide. The southern city of Karachi is regarded as a cornerstone of Pakistan's economy, with an estimated population of over 17 million people, with a gross domestic product of approximately $144 billion [11][12].
The prevention of cancer in the workforce of Karachi is therefore of tantamount importance to Pakistan's economy as a whole. Furthermore, being located closer to the equator, the city of Karachi receives higher UVR levels, placing its denizens at more risk [13]. Medical students are exposed to harmful UV-A and UV-B radiation during transportation and whilst walking to classes or taking part in summer activities. Use of sunscreen has also been tied to factors such as gender and nationality. A study amongst European university students from 13 different countries found that 83.0% of men and 94.0% of women were sunbathed, and that sun protection use whilst sunbathing was 63.0% in men and 87.0% in women [14]. Furthermore, there has never been a study of this scope conducted within Pakistan regarding the use of sunscreen and its predictors. Thus, our study aims to fill this gap in research by uncovering such predictors and also by evaluating the frequency of sunscreen use by medical students in day-to-day work. In a developing country like Pakistan which is already plagued by multifarious problems, the increasing incidence of melanomas is an additional burden on human and socio-economic resources. Hence, the collected data and its findings could be used to subsequently create policies to combat conditions caused by UVR, and thus alleviate some of the burden placed on the Pakistani healthcare system.

Study Design and Participants
A multi-center cross-sectional study was conducted from April to May 2018 in Karachi. Using the random sampling technique, self-administered questionnaires were distributed amongst students of multiple medical universities in Karachi and a total of 578 responses were received. The participants gave informed consent in writing, and were assured that participation in the study was voluntary and anonymity would be maintained. Only students enrolled in the Bachelors of Medicine and Bachelors of Surgery (MBBS) programs of these universities were included in this study.

Questionnaire
A literature search was done for studies related to sun awareness and sunscreen use before crafting the questionnaire. The questionnaire comprised three sections with a total of 32 questions. The first section collected information on demographics: age, gender, university, and socio-economic level. The second section included a set of questions investigating skin type using the Fitzpatrick scale [15], sun exposure and sun protection habits, knowledge regarding sun exposure, sunscreen and skin cancer and whether this knowledge had any effect on their sun protection habits. In the second section, the participants were also asked what factors would encourage them to use sunscreen as an open-ended question. The third section was designed for sunscreen users and contained questions inquiring about the reason of use, the frequency of application, the type and sun protection factor (SPF) value of the sunscreen used, and on what basis it was chosen.

Statistical Analysis
The data were entered and analyzed using SPSS version 24.0 (IBM, Armonk, NY). Basic descriptive analyses were performed for all independent variables. Differences in personal preferences and habits regarding sun exposure and sun protection were analyzed using the chi-squared test. P-values less than 0.05 were taken as significant.

TABLE 3: Knowledge of Sunscreen and Sun Exposure Characteristics Amongst Medical Students
Significantly more females were knowledgeable regarding the effectiveness of sunscreen in preventing sunburn (p=0.017) and aging (p<0.001). A significant association was also found between gender and the use of sunscreen, with females showing a much higher use of sunscreen as a protection method. Increased use of sunscreen, due to awareness of skin cancer from sun exposure, was also significantly associated with gender (   Factors which were associated with the use of sunscreen included gender (p<0.001) and the risk of getting sunburned easily (p=0.001) as observed in Table 6. Other variables tested included skin type, length of sun exposure, time spent swimming and playing sports, time spent on social media, tan preference and a family history of skin disorders. These variables did not show a significant association with sunscreen use ( Table 6).

Discussion
This cross-sectional study comprising 597 medical students sought to assess the knowledge, attitudes and practices of these students regarding sunscreen. We found varying levels of knowledge of the protective effects of sunscreen, with an overall intermediate to poor understanding among students. Less than half of the students were aware of the ability of sunscreen to prevent skin cancer and aging [16][17][18], while only 9.5% of participants knew that sunscreen can reverse the signs of aging [19]. Furthermore, female students were significantly more aware of the protection offered by sunscreen against sunburn and skin aging, and were compelled to utilize sunscreen due to their knowledge more than their male colleagues. This is in concert with previously published studies [20][21][22]. A possible explanation for this could be the more image-conscious and appearance-focused nature of women compared with men [23].
Moreover, around three-fifths of the students in our study liked themselves most when they were not tanned, which is in concordance with another Asian study [24]. Consequently, avoidance of tanning and sunburn were cited as the major reasons for sunscreen use by our cohort. This is in contrast to the study conducted by Awadh et al. [25], in which medical students cited friends and media as the main influencers of sunscreen use. Surprisingly, half of the students in our sample avoided sunscreen as they claimed it made their skin looks "greasy/oily." The prevalence of sunscreen use was 69.5% in our population, which was slightly higher than the 61.0% and 59.0% prevalence reported by Jerkegren et al. [26] and Alberg et al. [27], respectively. The hot and humid climate of Karachi might play a part in this elevated prevalence of sunscreen use. Furthermore, data were collected during the summer months of April to May which could also contribute to the increased sunscreen use observed in our study. About half of students who reported sunscreen use applied it at least 30 minutes before sun exposure, which is recommended for adequate binding to the skin [28 -29].
Given the lack of awareness regarding the protective effects of sunscreen against skin cancer and aging, medical students should be educated with the help of awareness campaigns and initiatives. Medical students represent a vital asset to society as future health care providers; hence, equipping them with adequate knowledge on sunscreen benefits would ultimately lead to increased sunscreen use among both patients and the general population.

Limitations
Our study has some limitations. Convenience sampling was used, which may introduce selection bias. Sunscreen use was self-reported by the participants and could not be verified. Questionnaires were filled during the summer months of April to May which may not reflect sunscreen use attitudes and practices throughout the year. The frequency of sunscreen use per day was not recorded and should be explored in future studies.

Conclusions
Sunscreen use was prevalent among a significant majority of medical students. However, knowledge regarding the protective effects of sunscreen, particularly against skin cancer and aging, was observed to be deficient in our cohort. The strongest predictors of sunscreen use were observed to be prevention of tanning and sunburn. Further measures to educate medical students in regard to the benefits of sunscreen should be undertaken to ultimately increase its use.

Additional Information Disclosures
Human subjects: Consent was obtained by all participants in this study. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work.
Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.